(draft) eia report for exploratory drilling - oil india ltd

Draft Environmental Impact Assessment Report

For

Exploratory Drilling In

Block MZ-ONN-2004/1 (Mizoram)

Oil India Limited Duliajan, Assam

GREEN TECH ENVIRONMENTAL ENGINEER & CONSULTANTS

Guwahati-28 Assam

www.greentecheec.org

I

EXECUTIVE SUMMARY PROJECT HIGHLIGHTS

The On-Shore NELP –VI BLOCK: MZ-ONN-2004/1 located in the Aizwal, Lunglei, and Mamit

and Serchhip districts of Mizoram has been allotted by Government of India to Oil India Limited (OIL) and M/S Shiv–Vani Oil & Gas Exploration Services Ltd. for exploration and production of hydrocarbons. OIL is the Operator of the onshore block.

The area of the block MZ-ONN-2004/1 is 3213 sq. km. and has the following coordinates:

Point Latitude, N Longitude, E A 23040’00.00” 92032’54.85” B 23000’00.00” 92035’58.00” C 23000’00.00” 93000’00.00” D 23040’00.00” 93000’00.00” A 23040’00.00” 92032’54.85”

The Block map is enclosed. As per the Minimum Work Program (MWP) of the Production Sharing Contract (PSC) signed with

the Government of India, OIL is required to Drill 06 (Six) wells .Three locations have been identified for drilling. The other three locations will be selected after further geo scientific studies and results of the drilled wells.

Each drilling location is finalized based on analysis of the seismic and other geo scientific data.

Sequential drilling of 06 (six) wells is planned. Tentative time of commencement of drilling is 2012. Drilling and testing of each well is expected to be completed in about 150 days.

In order to obtain the Environmental Clearance (EC) from the Ministry of Environment and Forests

(MoEF), OIL is required to carry out an Environmental Impact Assessment (EIA) study in the block to establish present baseline environmental scenario and the likely impact on the same as a result of proposed exploratory drilling and testing of the wells.

EIA report is prepared using primary baseline data collected at the site for nearly 5 weeks in non-

monsoon season (March and April, 2011) and secondary data collected from various sources in public domain as well as the project information provided by OIL.

Drilling rig and associated system will be used for drilling of the exploratory wells. Water Based

Mud (WBM) will be used as drilling fluid which is intrinsically safe and causes minimum environmental disturbances. Facilities for production testing will be created within each exploratory well site.

The block and adjoining areas belong to warm per-humid eco-region of North-Eastern Hills in Mizoram with red and laterite soils.

II

Tuirial, Mat, Tuikum, Tut and Tuichang rivers flow through and close to the block area. The block area is tortuous undulated forested terrain along with some thinly populated villages/towns and some agricultural fields in the plains portion of the block. Pollution Sources

Use of WBM for drilling is very eco-friendly and will cause minimum environmental disturbances.

Major liquid effluents during exploratory drilling and testing will be drilling discharges, drainage discharges, used/wasted WBM and domestic waste water.

Drilling discharges will have rock cuttings of sandstone, shale, etc. Wasted WBM will have

bentonite clay, barite and other nontoxic ingredients. Liquid effluents from effluent pits before discharge will be treated in Effluent Treatment Plant (ETP)

to meet on-shore discharge limits and treated effluents will be discharged in nearby river/nullah at a controlled rate, if required.

Gaseous emissions will be primarily exhaust gases produced from diesel driven power generators for

drilling rig operation and for other uses as well as diesel driven vehicles. These exhaust emissions will primarily contain SO2, NOx, CO, unburnt hydrocarbons etc. Dust will also be generated from vehicular movement on unpaved roads in the block area.

Formation fluids (Oil/Gas) generated from the exploratory wells will be tested at site for 3 to 4 days

to establish the hydrocarbon production potential.

Pollution Control Liquid effluents will be stored in HDPE lined shallow pits constructed within the exploratory drilling

location to prevent contamination of ground aquifers.

On well completion, effluent pits will be filled with drill cuttings and solid debris, covered with HDPE sheet and thick layer of soil to form a small mound with proper slope for rain water drainage.

Organic solid wastes including sewage and food leftovers generated at temporary camp facilities at

the exploratory well site will be disposed off as per approved procedure. Exhaust gases from various power generators will be discharged from stacks of appropriate heights

for dispersion in a wider area by atmospheric dispersion process and will result in extremely low incremental ground level concentrations of pollutants in nearby area only.

Formation water (if any) produced with oil during exploratory production testing of oil/gas will be

treated in a clarification system and treated effluents meeting the on-shore discharge standards will be discharged in nearby river/nullah at a controlled rate, if necessary.

Associated gas produced with oil during testing shall be separated and flared.

III

Project Benefits Oil and gas production, if commercially viable, will result in additional revenue generation for the

State and Central Governments and will assist in providing energy security to the country. It will also generate some employment potential and lead to infrastructure development of the block area.

BASELINE ENVIRONMENTAL CONDITIONS

Physiography and Topography

The block and surrounding area is a undulated forested terrain. Tuirial, Mat Tuikum, Tut and

Tuichang rivers flow through or close to the block area. Some agricultural fields are observed in the plains section of the block area along with some thinly populated villages/towns. Wild life Sanctuaries

Dampa Tiger Reserve forest is outside the block boundary and more than 20km away from the proposed location of OIL 4 & 5.

Tawi Wildlife Sanctuary is about 15 km from the proposed location OIL 2.

Khawnglung Wildlife Sanctuary is more than 40 Km away from the proposed location OIL 8.

Soils Area has soils derived from siltstones, shales and sandstones having sufficient water holding capacity

with relatively low fertility. Water Resources and Water Quality

Surface water is a perennial source of fresh water. The Tuirial, Mat, Tuikum, Tut and Tuichang rivers flow through the block area.

The monitored water quality indicates that surface water (rivers,streams) and ground water (handpump and spring) samples meet desirable limits for potable water and is fit for drinking.

Climatology and Meteorology

April is the hottest month and January is the coldest month with monthly mean maximum and minimum daily temperatures of nearly 27.2 and 17.90C, and 20.4 and 11.40C, respectively.

Average annual rainfall is 2244.7 mm. June month alone accounts for nearly 21.3% and December to

January month’s together account for only 0.6% of annual rainfall at Aizawl.

Ambient Air Quality

National ambient air quality standards for residential rural and other area are always met for PM10, PM2.5, SO2 NOx, VOC and Methane at all the locations.

IV

Land Use

The land use pattern indicates the presence of open forest.

Terrestrial Flora

Warm per-humid climate with moderate to heavy rainfall support a wide range of vegetation in the study area. Different types of orchids are also present.

Terrestrial Fauna

Existence of extensive forest ranges support fairly large variety of wildlife.

Agricultural Crops

Paddy, maize, oil seeds, pulses, vegetables, etc. are grown to limited extent in the block area.

Demographic and Socio-Economic

As per Census 2001, the sex ratio is 958 and literacy rate is 72.29%.

The study area has 47.06% main workers out of which 78.74% are cultivators, 1.94% are agricultural labourers, 1.70% are household industry workers and rest 17.62% are other workers. It is pertinent to note that agricultural activities are the main occupation in the block area.

There is essentially negligible industrial or commercial activity in the block.

ENVIRONMENTAL IMPACT ASSESSMENT Topography and Physiography Exploratory drilling and testing of the 06 (Six) wells for oil and gas will have negligible impact on

topography and physiography of the area.

Soils There will be no impact on soils of the area except for the collection of rock cuttings, bentonite

clay and other non-toxic ingredients of wasted WBM in HDPE lined effluents pits due to drilling of the wells.

Water Resources and Quality Tuirial, Mat Tuikum, Tut and Tuichang rivers are perennial rivers flowing in and close to the block

area. Water requirement is expected to be about 40 m3/d to meet drilling operations and 10 m3/d during testing operation at each well for a limited period. Further, recycling of treated water is likely to reduce the water requirement by about 10 m3/day.

The construction of HDPE lined shallow effluents pits will ensure that there is no adverse impact on

ground water or surface water quality of the block area. The discharge, if required, of treated effluents meeting on-shore discharge standards at a controlled rate will ensure that there is no perceptible adverse impact on surface water quality of nearby nullah/river.

V

Ambient Air Quality

Discharge of exhaust gas emissions from the DG Sets of the drilling rig and due to ground flaring of gaseous hydrocarbons produced during exploratory testing for 3 to 4 days at each of the wells using a properly designed flare pit will ensure that the impact of gaseous pollutants in exhaust emissions is insignificant in surrounding area.

Dust generated due to vehicular movement on unpaved roads will settle quickly and will not cause any dust problem in the area.

Noise

Suitable Acoustic enclosure will ensure that the noise levels at the boundary of well site operational area does not exceed 75 dB(A) during exploratory drilling and testing of the wells and this will ensure that there is insignificant impact of drilling on noise levels during day- and night-time in the surrounding village areas, if any . Land Use

There will be negligible impact on land use of the area because total land requirement for each

drilling location is expected to be only about 1.65 hectares. However, some additional land would also be required for making approach road to the drilling site.

Terrestrial Flora and Fauna

There will not be any perceptible adverse impact on the terrestrial flora and fauna of the area due to

exploratory drilling and testing activities.

Demographic and Socio-Economic The demography of the area will not be affected by temporary presence of nearly 40 to 50 persons

during drilling and testing operations for about 150 days at each location. No adverse impact can be expected on socio-economic conditions of the area during exploratory

drilling and testing operations. Slight beneficial impact on job opportunity may be expected because some local persons may get temporary employment as unskilled or semi-skilled workers during the drilling phase.

VI

Conclusions

The impact due to exploratory drilling and testing of the wells on various attributes of environment is

summarized below:

PROJECT ACTIVITY IMPACT Proposed access Some cutting of trees and earth

excavation/filling may be inevitable. Clearing and timber salvage Cutting of some trees and salvage of timber

may be involved for preparation of the drill site and approach road.

Wild life and habitat protection MoEF guidelines will be followed Fuel storage and handling Insignificant impact. Camps and staging Temporary mobile camp facilities will be

used for drilling operations. Liquid and solid waste disposal Insignificant temporary localized impact Cultural and archaeological sites

Not applicable

Selection of drilling sites The exploratory well sites will be selected after analysis of seismic & other Geo Scientific data.

Terrain stabilization Not applicable Protection of fresh water horizons

Not applicable since drilling effluents will be stored in HDPE lined shallow pits and well casing will protect deeper fresh water horizons.

Blowout prevention plan Necessary care will be taken during drilling and blowout preventors (BOP) will be installed at well mouth for any emergency

Flaring during completion and production testing

Separated gases will be flared in suitably designed ground flare pit to minimize adverse impact.

Abandonment of wells Will be applicable only if commercial production of oil/gas is unviable from the exploratory well.

Reclamation for abandonment Not applicable at present Noise control Necessary measures will be adopted Debris disposal Insignificant localized impact Protection of natural drainage and water flow

Natural drainage will be protected

VII

RISK ANALYSIS AND DISASTER MANAGEMENT PLAN Occurrence of blowout is the major hazard during drilling. However, Blow out preventer (BOP) shall

be installed on well head to prevent the same. Since only sweet oil and gas is expected in the block area, hazard due to occurrence of H2S is not

likely. Adequate fire fighting facilities will be deployed and suitable personal protective equipments

including breathing masks will be available at the drilling site. Doctor and First aid facility will be available at drilling site and a 24 hour standby vehicle

(ambulance) will also be available at the site for transport of injured persons to nearest hospital. Quantitative risk assessment indicates that three phase separator during exploratory well testing and

HSD storage tanks will have light fire and explosion hazard potential and low toxicity hazard potential.

On-site disaster management plan is suggested for quick and efficient emergency handling even

though OIL already has well formulated on-site and off-site emergency plans. ENVIRONMENTAL MANAGEMENT PLAN

Use of Water Base Mud (WBM) is very eco-friendly as a drilling fluid and does not require any

elaborate environmental management plan. Production testing for oil and gas at the exploratory wells will also not require any specific management plan.

Effluents pits will be shallow and HDPE lined to avoid contamination of ground aquifers. Cutting of some trees and earth cutting/filling, if considered necessary, should be minimized as far as

possible for exploratory drilling operational area and for making approach road for the movement of vehicles.

Personal protective equipments for dust and noise should be used whenever required.

Efforts should be made by OIL and its contractors to employ local persons for unskilled and semi-

skilled jobs and support activities.

An appropriate environmental monitoring programme during drilling and testing of wells is recommended.

************

INDEX

CHAPTER CONTENT PAGE NO.

1.

INTRODUCTION

1.1 INTRODUCTION 1-1 1.2 OIL INDIA. LTD. 1-1

1.2.1 CORPORATE OBJECTIVES OF OIL 1-2

1.2.2 ACTIVITIES OF OIL 1-2 1.3 OBJECTIVE OF EIA STUDY 1-3

1.4 SCOPE OF EIA STUDY 1-4

1.4.1 INTRODUCTION 1-4

1.5 BLOCK AREA/STUDY AREA 1-4

2.

POLICY FRAMEWORK

2.1 INTRODUCTION 2-1

2.2 OBJECTIVE OF EIA STUDY 2-1

2.3 PROTECTION OF ENVIRONMENT UNDER NELP / NOMINATION 2-2

2.4 ENVIRONMENTAL CLEARANCE PROCEDURE UNDER EIA 2006 2-3 2.5 STANDARDS FOR EMISSIONS AND DISCHARGE OF

ENVIRONMENTAL POLLUTANTS 2-5

2.5.1 LIQUID EFFLUENTS 2-5

2.5.2 GASEOUS EMISSIONS 2-6 2.5.2.1 DG SETS 2-6

2.5.2.2 ELEVATED / GROUND FLARES 2-6

2.5.3 DISPOSAL OF DRILL CUTTING AND DRILLING FLUIDS 2-6

3.

PROJECT DESCRIPTION


3.2 BLOCK MZ-ONN-2004/1 3-1

3.3 JUSTIFICATION AND BENEFITS OF THE PROJECT 3-2

3.4 BENEFITS OF THE PROJECT 3-2 3.5 DRILLING OF EXPLORATORY WELLS 3-3

3.6 OIL WELL DRILLING ACTIVITIES 3-4

3.7 RIG SELECTION 3-5 3.8 DRILLING OF OIL/GAS WELL 3-9

3.9 WELL EVALUATION 3-17

3.10 COMPLETION OF DRILLING 3-18

3.11 RIG DEMOBILIZATION 3-19

3.12 MANPOWER AND OTHER REQUIREMENTS 3-19 3.13 EXPLORATORY DRILLING POLLUTION SOURCES 3-22

3.14 TREATMENT AND DISPOSAL STRATEGY FOR POLLUTANTS 3-24

3.15 ANALYSIS OF ALTERNATIVES 3-26

4.

BASELINE ENVIRONMENTAL CONDITIONS: PHYSICAL, BIOLIGICAL, DEMOGRAPHIC AND SOCIO-ECONOMIC


4.2 SAMPLING/MONITORING LOCATIONS 4-1 4.3 PHYSICAL ENVIRONMENT 4-1

4.3.1 TOPOGRAPHY AND PHYSIOGRAPHY 4-1

4.3.2 SOILS 4-2 4.3.3 WATER RESOURCES AND WATER QUALITY 4-4

4.3.3.1 WATER RESOURCES 4-4

4.3.3.2 RAINFALL IN THE STUDY AREA 4-4 4.3.3.3 SURFACE AND GROUND WATER RESOURCES 4-4

4.3.3.4 WATER QUALITY IN STUDY AREA 4-6

4.3.4 CLIMATOLOGY AND METEOROLOGY 4-7 4.3.4.1 INTRODUCTION 4-7

4.3.5 AMBIENT AIR QUALITY 4-8

4.3.5.1 INTRODUCTION 4-8

4.3.5.2 METHODOLOGY OF MONITORING AND ANALYSIS 4-8

4.3.5.3 AMBIENT AIR QUALITY 4-9

4.3.5.4 AMBIENT AIR QUALITY STATUS 4-9 4.3.6 AMBIENT NOISE LEVELS 4-11

4.3.6.1 INTRODUCTION 4-11

4.3.6.2 METHODOLOGY 4-11

4.3.6.3 EQUIVALENT SOUND ENERGY LEVEL OR LEQ 4-12

4.3.6.4 AMBIENT AIR QUALITY STANDARDS IN RESPECT OF NOISE 4-12

4.3.6.5 LAND USE 4-13

4.3.6.6 LAND USE: SCOPE AND LIMITATIONS 4-13 4.4 BIOLOGICAL ENVIRONMENT 4-23


4.4.2 TERRESTRIAL FLORA 4-24 4.4.3 TERRESTRIAL FAUNA 4-31

4.4.4 AGRICULTURAL CROPS IN THE STUDY AREA 4-39

4.5 DEMOGRAPHIC ENVIRONMENT 4-40


4.5.2 POPULATION 4-40 4.5.3 POPULATION DENSITY 4-41

4.5.4 SEX RATIO 4-41

4.5.5 SCHEDULED CASTES AND SCHEDULED TRIBES 4-42 4.5.6 LITERACY 4-42

4.6 SOCIO-ECONOMIC ENVIRONMENT 4-43


4.6.2 EMPLOYMENT PATTERN 4-43 4.6.3.1 EDUCATIONAL FACILITIES 4-45

4.6.3.2 MEDICAL FACILITIES 4-45

4.6.5 INDUSTRIAL AND COMMERCIAL ACTIVITIES 4-45

5.

ENVIRONMENTAL IMPACT ASSESSMENT

5.1 INTRODUCTION 5-1 5.2 TOPOGRAPHY AND PHYSIOGRAPHY 5-1

5.3 SOILS 5-1

5.4 WATER RESOURCE AND WATER QUALITY 5-2

5.5 CLIMATOLOGY AND METEOROLOGY 5-2

5.6 AMBIENT AIR QUALITY 5-3

5.7 NOISE AND VIBRATIONS 5-4 5.8 LAND USE 5-4

5.9 BIOLOGICAL ENVIRONMENT 5-5

5.9.1 TERRESTRIAL FLORA 5-5 5.9.2 TERRESTRIAL FAUNA 5-6

5.10 DEMOGRAPHIC AND SOCIO-ECONOMIC ENVIRONMENT 5-7

5.11 CONCLUSIONS 5-7

6.

RISK ASSESSMENT AND CONSEQUENCE ANALYSIS

6.1 RISK ASSESSMENT, CONSEQUENCE ANALYSIS AND OCCUPATIONAL SAFETY DURING DRILLING AND PRODUCTION TESTING

6-1


6.1.2 IDENTIFICATION OF HAZARDS IN DRILLING AND PRODUCTION TESTING

6-2

6.1.2.1 MINOR OIL SPILL 6-2 6.1.2.2 MAJOR OIL SPILL 6-2

6.1.2.3 BLOWOUT 6-3

6.1.2.4 HYDROGEN SULPHIDE (H2S) 6-3

6.1.3 CONTROL MEASURES FOR MAJOR HAZARDS 6-4

6.1.3.1 BLOWOUT 6-4 6.1.3.2 CONTROL MEASURES FOR H2S DURING DRILLING 6-7

6.1.3.3 CONTROL MEASURES FOR H2S DURING PRODUCTION TESTING 6-9

6.1.4 FIRE FIGHTING FACILITY 6-9 6.1.4.1 FIRE WATER SYSTEM 6-9

6.1.4.2 FIRST AID FIRE FIGHTING EQUIPMENTS AT DRILLING RIG 6-9

6.2 FIRE FIGHTING EQUIPMENTS FOR PRODUCTION TESTING FACILITIES

6-11

6.3 MEDICAL FACILITIES 6-12 6.4 QUANTATIVE RISK ASSESSMENT 6-12

6.4.1 FIRE AND EXPLOSION INDEX & TOXICITY INDEX 6-12

6.4.1.1 HAZARDOUS MATERIAL IDENTIFICATION METHODOLOGY 6-13 6.4.1.2 F&EI COMPUTATION 6-14

6.4.1.3 TOXICITY INDEX (TI) 6-14

6.4.1.4 HAZARDS RANKING 6-14

6.4.2 CONSEQUENCE ANALYSIS 6-14

6.4.2.1 CONCLUSIONS 6-15

6.4.2.2 RECOMMENDATIONS FOR RISK REDUCTION 6-15

7

DISASTER MANAGEMENT PLAN


7.2 CRISIS MANAGEMENT TEAM OF OIL 7-2

7.3 EMERGENCY CLASSIFICATION 7-2

7.3.1 LEVEL 1 EMERGENCY 7-2 7.3.2 LEVEL 2 EMERGENCY 7-3

7.3.3 LEVEL 3 EMERGENCY 7-3

7.4 METHODOLOGY OF DMP PREPARATION 7-3

7.5 ON-SITE DISASTER MANAGEMENT PLAN 7-4

7.5.1 SITE MAIN CONTROLLER 7-4

7.5.2 THE SITE INCIDENT CONTROLLER TEAM 7-4

7.5.3 THE AUXILIARY TEAM 7-4 7.5.4 RESPONSIBILITIES OF SITE MAIN CONTROLLER (SMC) 7-4

7.5.5 RESPONSIBILITIES OF SITE INCIDENT CONTROLLER (SIC) 7-5

7.5.6 RESPONSIBILITIES OF AUXILIARY TEAM CONTROLLER (ATC) 7-5 7.5.7 RESPONSIBILITIES OF SIC SUPERVISORS 7-6

7.5.8 RESPONSIBILITIES OF ATC SUPERVISORS 7-6

7.5.9 WARNING SYSTEM 7-6

7.5.10 EMERGENCY PLAN INITIATION 7-7

7.5.11 EMERGENCY PROCEDURES 7-7 7.5.11.1 LEVEL 1 EMERGENCIES 7-7

7.5.11.2 LEVEL 2 EMERGENCIES 7-7

7.5.11.3 LEVEL 3 EMERGENCIES 7-7 7.5.12 ACCIDENT SITE CLEAN UP 7-8

7.5.13 EMERGENCY RESPONSE PERSONNEL SAFETY 7-8

7.6 ALL CLEAR SIGNAL AND PUBLIC STATEMENT 7-8

8

ENVIRONMENTAL MANAGEMENT PLAN


8.2 MITIGATIVE MEASURES FOR MINIMISING ENVIRONMENTAL IMPACTS

8-1

8.2.1 GENERAL MEASURES REQUIRED DURING DRILLING AND TESTING

8-1

8.2.2 SPECIFIC MEASURES REQUIRED DURING DRILLING AND PRODUCTION TESTING

8-2

8.2.3 ENVIRONMENTAL MONITORING 8-4

8.2.4 OCCUPATIONAL HEALTH SURVEILLANCE PROGRAMME 8-4

9

CONSULTANTS ENGAGED

9-1

LIST OF TABLES

TABLE 4.1 SOIL CHARACTERISTICS IN STUDY AREA 4-3

TABLE 4.2 DISTRICT –WISE MONTHLY AVERAGE RAINFALL 4-2

TABLE 4.3 WATER QUALITY AT STUDY AREA 4-7

TABLE 4.4 AMBIENT AIR QUALITY IN MIZORAM BLOCK 4-10

TABLE 4.5 AMBIENT AIR QUALITY IN MIZORAM BLOCK( VOC) 4.11

TABLE 4.5 AMBIENT STANDARDS IN RESPECT OF NOISE 4-12

TABLE 4.6(a) LIST OF FLORA IN STUDY AREA 4-24

TABLE 4.6(b) LIST OF FAUNA STUDY AREA 4-31

TABLE 4.7(a) POPULATION OF STUDY AREA (2001) 4-40

TABLE 4.7(b) HOUSEHOLD AND HOUSEHOLD SIZE OF STUDY AREA (2001) 4-41

TABLE 4.8 EDUCATION LEVEL AND WORK STATUS 4-42

TABLE 4.9 EMPLOYMENT PATTERN 4.43

TABLE 6.1 CHARACTERISTICS OF H2S GAS 6-17

TABLE 6.2 DETERMINATION OF THE FIRE AND EXPLOSION INDEX AND OF THE TOXICITY INDEX

6-18

TABLE 6.3 HAZARD RANKING 6-20

TABLE 6.4 TOLERABLE RADIATION INTENSITIES FOR VARIOUS OBJECTS 6-20

TABLE 6.5 DAMAGE DUE TO INCIDENT RADIATION INTENSITY 6-21

LIST OF PLATES

PLATE 4.1 CARRYING OF WATER IN CART 4-5

PLATE 4.2 HUMAN SETTLEMENT 4-23

PLATE 4.3 OPEN FOREST 4-23

LIST OF FIGURES

FIG 1.1 LOCATION MAP OF THE PROPOSED PROJECT SITE WITH ROAD NETWORK 1-6

FIG 1.2 LAYOUT MAP OF BLOCK MZ-ONN-2004/1 1-7

FIG 3.1 DRILLING RIG AND ALLIED EQUIPMENTS 3-5

FIG 3.2 DRILLING RIG 3-8

FIG 3.3 WELL BORE DIAGRAM 3-10

FIG 3.4 A TYPICAL BOP STACK 3-16

FIG 4.1 LOCATION MAP OF PROPOSED SITE 4-14

FIG 4.2 ETM 4-15

FIG 4.3 LAND USE CLASSES AROUND THE PROPOSED PROJECT 4-16

FIG 4.4 LOCATION MAP OF LOCATION 4 AND 5 4-17

FIG 4.5 ETM OF LOCATION 4 AND 5 4-18

FIG 4.6 LAND USE CLASSES AROUND LOCATION 4 AND 5 4-19

FIG 4.7 LOCATION MAP OF LOCATION 8 4-20

FIG 4.8 ETM OF LOCATION 8 4-21

FIG 4.9 LAND USE CLASSES AROUND LOCATION 8 4-22

EIA for Exploratory Drilling & Testing in Block MZ-ONN-2004/1 (Mizoram) 1-1

GREEN TECH Environmental Engineer & Consultants

CHAPTER 1: INTRODUCTION

1.1 INTRODUCTION

A consortium of Oil India Ltd. (OIL) with 75% participating interest (PI), Shiv-Vani

Oil & Gas Exploration Services with 15% PI and Suntera Resources Ltd. with 10% PI

has signed a production sharing contract (PSC) with the Government of India for the

exploration and production of hydrocarbons in the Exploration Block MZ-ONN-2004/1

falling in Lunglei, Serchhip, Aizawl and Mamit districts in Mizoram under NELP-VI.

PSC designates OIL as the Operator of the block. The block is located in central part of

Mizoram primarily within Lunglei, Serchhip and Aizawl districts eventhough a small

portion falls in Mamit district. The total area of the block is 3213 sq. km and lies

towards south of Aizawl, the capital city of Mizoram. To best of our knowledge,

exploratory drilling has not been carried at any place in the block so far.

Acquisition, processing and interpretation of 2-D and 3-D Seismic Survey, Gravity

Magnetic Survey, Geochemical Survey are in progress for the block MZ-ONN-2004/1.

Based on seismic data analysis, OIL is planning to carry out exploratory drilling and

testing at 5 promising locations in Phase I within 2007-2012 and at 1 location in Phase

II during 2012-15 period within the block area as per the minimum work programme

(MWP) outlined in PSC to establish the techno-economic viability for production of

hydrocarbons in the block area within a period of 8 years, that is, 2007-15. In addition

to these exploratory wells, as per PSC requirement, additional appraisal/delineation

wells need to be drilled for commercial production in case of discovery of oil/gas. The

location of block MZ-ONN-2004/1 in administrative map of Mizoram, capital city

Aizawl and other important town/villages are shown in Fig. 1.1. The Capital city

Aizawl is nearly 5 km north of the northern boundary of the block.

1.2 OIL INDIA LTD.

The story of Oil India Limited (OIL) symbolizes and traces the development and

growth of India’s petroleum industry. From the first commercial discovery of crude oil

in the far east of India at Digboi (Assam) to becoming a fully integrated upstream

petroleum company, OIL has traversed a great distance. In the process, it has crossed

many a milestone.

In 1889, crude oil was first discovered in the fields of Digboi. On 18th February, 1959,

Oil India Private Limited was incorporated to expand and develop the newly discovered

oil fields of Naharkatiya and Moran in the North East of India. In 1961, OIL became a



joint venture company between the Government of India and Burmah Oil Company

Limited, UK.

Two decades later, in 1981, Oil India Limited became a wholly owned Government of

India enterprise. Today, Oil India Limited (OIL) is a premier Indian National Oil

Company engaged in the business of Exploration, Development and Production of

Crude Oil and Natural Gas, Transportation of Crude Oil and Production of LPG. The

Company also provides various E&P related services to the industry and holds 26%

equity in Numaligarh Refinery Ltd.

1.2.1 Corporate Objectives of OIL

Exploration for new oil and gas reserves.

Development of discovered oil fields and increased recovery from matured and

developed fields.

Acquisition of new exploration acreage and oil and gas producing properties.

Venturing into oil fields service sector and participation in mainstream activities.

Enhanced implementation of EHS measures in operations.

Sustain and promote environmental protection.

Optimum utilization of human resources.

Engage in Corporate Social Responsibility activities in operational areas.

Ensure reasonable return on capital and optimize cost of production.

1.2.2 Activities of OIL

OIL is operating in 53 blocks and has participating interest in another 16 blocks with a

total of over 1,00,000 sq. km of licensed areas. It produces 70,000 bbls/day of crude oil

and 260 MMSCFD of natural gas, with a total production of oil and oil equivalent of

1,11,000 bbls/day.

To achieve its vision to be the fastest growing company, the company has realized the

need to look beyond the shores of India. Aggressively seeking for overseas business

opportunity is one of the strategic goals of OIL. Within a short span of 4-5 years, OIL is

already present in 6 countries like Iran, Libya, Gabon, Sudan, Yemen and Nigeria. The

focus is also on West Africa, CIS countries, Middle-East countries, etc. With the

discovery of heavy oil in Farsi Block in Iran, OIL already has tasted its first success

overseas.



1.3 OBJECTIVE OF EIA STUDY

It is recognized that the petroleum operations, such as, exploration for oil and gas and

their production, transportation and storage will cause some impact on the environment

of the block area and its surrounding area. It is, therefore, expected that the petroleum

operations shall be carried out with proper regard to concerns with respect to protection

of the environment and conservation of natural resources in the contract and

surrounding areas. Accordingly, the Government of India issued guidelines to the

contractor of exploration block for execution of environmental work as a part of the

production sharing contract (PSC). Briefly these are as follows:

use of advanced techniques, practices and methods of operation to prevent

environmental damage;

take measures, in consultation with the Government to minimize adverse impact on

the environment where some adverse impact on the environment is unavoidable;

prepare contingency plan for oil spills, fires and other emergencies before

commencement of drilling operations; and

remove installation and restore site after the expiry of contract.

OIL desires that the environmental impact assessment (EIA) study should not be limited

to areas close to 6 exploratory wells where drilling is likely to commence in the year

2011 but should also include other block area because exact locations are not yet

identified and will be finalized only after completion of seismic, gravity magnetic and

geochemical data acquisition, processing and interpretation well before the tentative

commencement of exploratory drilling in the year 2011. Furthermore, the selection of

promising locations is a dynamic process resulting in changes in coordinates of drilling

locations on the basis of results of testing of wells already drilled as well as further

analysis of seismic and other data. Drilling operation is planned sequentially. EIA study

related to exploration drilling and testing operations is required to be completed before

commencement of drilling operations under E&P programme and shall be submitted by

the Operator and specific approval, that is, environmental clearance (EC) from Ministry

of Environment and Forests (MoEF), Government of India, and consent to establish

(NOC) and consent to operate under Air and Water Acts from MSPCB will be required

as per EIA notification dated 14th September 2006 (EIA 2006).



1.4 SCOPE OF EIA STUDY

1.4.1 Introduction

The purpose of REIA is to identify and evaluate the potential impacts (beneficial and

adverse) of proposed drilling of 8 exploratory wells within 2012 in Phase I and 1 more

exploratory well during 2012-15 period in Phase II as a part of proposed E&P

programme in the block MZ-ONN-2004/1.The EIA Study to be carried out as per TORs

F.No.J-11011/877/2007-IA II (I) dated 24th Dec, 2007

1.5 BLOCK AREA/STUDY AREA

Fig. 1.1 shows the administrative map of Mizoram and the location of block MZ-ONN-

2004/1 in Mamit, Aizawl, Serchhip and Lunglei districts.

The block lies in the central part of Mizoram. Mizoram has Bangladesh towards west

and Myanmar towards south and east. The block area is well connected by NH-54 and a

network of other all weather roads though journey time is quite large due to tortuous

undulated forested terrain. The nearest railhead is Silchar in Assam. National Highway

(NH-54) runs north-to-south connecting Silchar to Aizawl, Serchhip, Lunglei,

Lawngtlai, Saiha and Tuipang V. Aizawl is the capital city of Mizoram and is nearly 5

km north of northern boundary A-D of the block. Aizawl is linked by air to the rest of

India and the nearest international airport is located at Kolkata in West Bengal.

Fig. 1.2 shows the lay out map of the block MZ-ONN-2004/1.

The block has a trapezium shape and lies between 23000’00” to 23040’00” N latitude

and 92032’54.85” to 93000’00.00” E longitude and is located on Survey of India

toposheets 84 A/10, 11, 12, 14, 15 and 16 (all restricted). The block coordinates are as

follows:

Point Latitude, N Longitude, E

A 23040’00.00” 92032’54.85”

B 23000’00.00” 92035’58.00”

C 23000’00.00” 93000’00.00”

D 23040’00.00” 93000’00.00”

A 23040’00.00” 92032’54.85”

Agro-ecologically the block area is North-eastern Hills (Purvanchal), warm, perhumid

ecoregion, with red and lateritic soils. Soils have been derived from siltstones,



sandstones and shales. The climate is tropical warm and per-humid with an average

annual rainfall of nearly 2400 to 3500 mm. However, due to complexity of

physiography various microclimates prevail from high elevation to low elevation.

Since 2-D and 3-D seismic survey, gravity magnetic survey and geochemical survey are

likely to cover the entire block area except area under wildlife sanctuary/national park,

if any, the entire block area of 3213 sq. km is considered as the study area. The area

is thinly populated undulating forested terrain interspersed with rivers/nullahs with

some agricultural fields existing in plains section of the block area.



FIG 1.1: LOCATION MAP OF THE PROPOSED PROJECT SITE WITH

ROAD NETWORK



FIG 1.2: LAY OUT MAP OF THE BLOCK MZ-ONN-2004/1



CHAPTER 2: POLICY FRAMEWORK

2.1 INTRODUCTION

In India, Environment Impact Assessment (EIA) was made mandatory as per

Environmental Impact Assessment notification dated 27.01.1994 (EIA 1994).

Ministry of Environment and Forests (MoEF) issued a new EIA notification

on 14.09.2006 (EIA 2006) which supersedes EIA 1994 under the purview of

Environmental (Protection) Act of 1986 with the following objectives:

Identify and predict likely impacts based on activities of those components

of project which directly interact with the environment.

Find ways and means to reduce adverse impacts.

Shape the projects to suit local environment.

Present the predictions and options to the decision-makers or statutory

bodies, such as, State Pollution Control Board, Ministry of Environment &

Forests (MoEF), Government of India, Director General of Hydrocarbons

(DGH), etc.

2.2 OBJECTIVE OF EIA STUDY

The EIA study is expected to cover at least the following matters:

Description of the proposed activities including likely waste generation

and measures incorporated to meet environmental standards.

Description of the base environmental and climatic conditions.

Analysis of land use pattern, water consumption (and water balance),

power consumption, etc. along with the social and health impacts.

An assessment of likely or potential environmental impacts of the

proposed activity (like air, water and soil pollution, noise generation) and

the alternatives, including the direct or indirect, cumulative, short-term and

long-term effects.

An environmental management plan to mitigate or ameliorate negative

effects on environment including post implementation monitoring

programme.

The EIA report for all offshore and onshore oil and gas exploration,

development and production projects shall be submitted to MoEF for



environmental clearance following the procedure prescribed in EIA 2006. The

EIA report shall also be submitted to DGH for approval.

2.3 PROTECTION OF ENVIRONMENT UNDER NELP/NOMINATION

In early 1990s, Government of India (GOI) formulated a New Exploration

Licensing Policy (NELP) under Ministry of Petroleum and Natural Gas

(MoP&NG) to encourage private sector participation for exploration and

production (E&P) of oil and gas both by Indian and foreign E&P operators on

Production Sharing Contract (PSC) basis to meet ever rising demand of

petroleum products in India. The PSC is a mutual agreement between GOI and

an Operator. Article 14 on Protection of Environment is now also applicable to

old blocks/areas which were awarded prior to the formulation of NELP for

exploration and production of oil and gas and are not under PSC.

As per Article 14 on Protection of Environment, the Government and the

Contactor (OIL) recognize that the petroleum operations will cause some

impact on the environment in the contract or license area. Accordingly in

performance of the contract the operator shall conduct its petroleum operations

with due regard to concerns with respect to protection of the environment and

conservation of natural resources.

Environmental clearance is now necessary from the regulatory authority

(MoEF) for exploratory surveys and drilling as well as production to be

undertaken by the Operator. Conditions as applicable under such

environmental clearance based on the Environmental Impact Assessment

reports are required to be followed by the Operator. GOI monitors the

implementation of these conditions. Some of the conditions include:

1. No survey or drilling or production activity can be conducted in national

parks, sanctuaries, mangroves, wetlands of national importance, bios-

sphere reserves and other biologically sensitive areas.

2. Passage through national parks, sanctuaries, mangroves and wetlands of

national importance and biosphere reserves would not be permitted.

However, if there is no passage other than through these places to reach a

particular point of survey or drilling or production beyond, then the



Operator may obtain the permission of the concerned authorities (Chief

Wildlife Warden/ Director of the Biosphere Reserve)

3. In case cutting of trees being involved for survey or drilling or production

purpose, compensatory afforestation would be done within a time frame.

4. Approval for diversification of forest land involved, if any, would have to

be obtained specifically in each case.

5. Advanced techniques, practices and methods are to be used to prevent

environmental damage.

6. Measures are to be taken in consultation with the Government to minimize

adverse impact on the environment where some adverse impact on the

environment is unavoidable.

7. Three EIA studies are to be carried out as under:

First EIA study is to be carried out before any field work relating to

seismic or other survey;

Second EIA study is to be carried out before commencement of

exploration drilling operations; and

Third EIA study is to be carried out before commencement of

production operations.

8. Contingency plan for oil spills, fires and other emergencies is to be

prepared before commencement of drilling and production operations.

9. Installation is to be removed and site is to be restored after the expiry of

contract.

10. The Government may revoke clearance if implementation of the above

conditions is not satisfactory.

11. The above conditions will be enforced inter alia under the provisions of the

Water (Prevention and Control of Pollution) Act 1974, Air (Prevention and

Control of pollution) Act 1981 and the Environment (Protection) Act,

1986 and the Public Liability Insurance Act, 1991 along with their

amendments and rules.

2.4 ENVIRONMENTAL CLEARANCE PROCEDURE UNDER EIA 2006

EIA 2006 categorizes all oil and gas exploration, development and production

projects under category A, except for seismic and other exploratory surveys,



and require project proponents to apply on prescribed Form 1 for prior

environmental clearance (EC) to MoEF before commencing any construction

activity or preparation of land at the site. EC process will involve three stages,

namely, Scoping, Public Consultation and Appraisal. Scoping involves

finalization of comprehensive terms of reference (ToR) for the preparation of

draft EIA report by the Expert Appraisal Committee (EAC) of MoEF. Public

Consultation, except for seismic and other exploratory, survey will be carried

out by the State Pollution Control Board to ascertain the concerns of local

affected persons and others who have plausible stake in the environmental

impact of the project by making available the Summary of EIA Report and

holding a Public Hearing as per the prescribed procedure. EAC will then carry

out the appraisal of the application including final EIA report and outcome of

public consultation including public hearing proceedings for grant of EC.

Environment Impact Assessment Authority (EIAA), that is, MoEF will then

consider the recommendation of EAC for the grant of EC. Prescribed time

frame for various stages for EC are: 60 days by EAC for finalization of TOR

after submission of application on Form 1, 45 days for public consultation

after receiving request for the same from project proponent along with EIA

report and summary of the EIA report, 60 days by EAC for appraisal after

receipt of final EIA report and proceeding of public hearing, and 45 days by

MoEF for considering the recommendation of EAC for the grant of EC. It is

presumed that the baseline data collection will start after finalization of ToR

and time required for the same and for the preparation of draft EIA report as

well as that required for preparation of final EIA report after considering

material environmental concerns expressed during public consultation will be

in addition to the prescribed time frame specified above.

2.5 STANDARDS FOR EMISSIONS AND DISCHARGE OF ENVIRONMENTAL POLLUTANTS

For the purposes of protecting and improving the quality of the environment

and preventing and abating environmental pollution, the standards for

emissions and discharge of environmental pollutants from Oil Drilling and

Gas Extraction Industry situated on land and away from saline water sink

specified by MoEF are as follows



2.5.1 Liquid Effluents

Industry may opt either for disposal of treated water by on-shore disposal or

by re-injection in abandoned well, which is allowed only below a depth of

1000 metres from the ground level. In case of re-injection in abandoned well

the effluent have to comply only with respect to suspended solids and oil and

grease at 100 mg/l and 10 mg/l, respectively. For on-shore disposal, the

permissible limits are given below:

Sl.

No.

Parameter On-shore discharge standards

(Not to Exceed)

1. pH 5.5 - 9.0

2. Temperature 400C

3. Suspended Solids 100 mg/l

4. Zinc 2 mg /l

5. BOD 30 mg/l

6. COD 100 mg/l

7. Chlorides 600 mg/l

8. Sulphates 1000 mg/l

9. TDS 2100 mg/l

10. % Sodium 60 mg/l

11. Oil and Grease 10 mg/l

12. Phenolics 1.2 mg/l

13. Cyanides 0.2 mg/l

14. Fluorides 1.5 mg/l

15. Sulphides 2.0 mg/l

16. Chromium (Cr+6) 0.1 mg/l

17. Chromium (Total) 1.0 mg/l

18. Copper 0.2 mg/l

19. Lead 0.1 mg/l

20. Mercury 0.01 mg/l

21. Nickel 3.0 mg/l



2.5.2 Gaseous Emissions

2.5.2.1 DG Sets

DG sets at drill site as well as production station shall conform with the norm

notified under the Environment (Protection) Act, 1986.

2.5.2.2 Elevated/Ground Flares

A. Cold Venting of gases shall never be resorted to and all the gaseous

emissions are to be flared.

B. All flaring shall be done by elevated flares except where there is any effect

on crop production in adjoining areas due to the flaring. In such cases, one

may adopt ground flaring.

C. In case of ground flare, to minimize the effects of flaring, the flare pit at

Group Gathering Station (GGS), Oil Collecting Station (OCS) and Group

Collection Station (GCS) shall be made of RCC surrounded by a

permanent wall (made of refractory brick) of minimum 5 m height to

reduce the radiation and glaring effects in the adjoining areas.

D. A green belt of 100 m width may be developed around the flare after the

refractory wall in case of ground flaring.

E. If the ground flaring with provision of green belt is not feasible, enclosed

ground flare system shall be adopted, and be designed with proper

enclosure height, to meet the ground level concentration (GLC)

requirement.

F. In case of elevated flaring, the minimum stack height shall be 30 m.

Height of the stack shall be such that the maximum GLC never exceeds

the prescribed ambient air quality limit.

G. Burning of effluent in the pits shall not be carried out at any stage.

2.5.3 Disposal of Drill Cutting and Drilling Fluids

A. Drill Cuttings (DC) originating from on-shore or locations close to shore

line and separated from Water Base Mud (WBM) should be properly

washed and unusable drilling fluids (DF) such as WBM, Oil Base Mud

(OBM), Synthetic Base Mud (SBM) should be disposed off in a well

designed pit lined with impervious liner located off-site or on-site. The



disposal pit should be provided additionally with leachate collection

system.

Design aspects of the impervious waste disposal pit; capping of disposal

pit should be informed by the oil industry to State Pollution Control Board

(SPCB) at the time of obtaining consent.

B. Use of diesel base mud is prohibited. Only WBM should be used for on-

shore oil drilling operations.

C. In case of any problem due to geological formation for drilling, low

toxicity OBM having aromatic content <1% should be used. If the

operators intend to use such OBM to mitigate specific well problem/SBM

it should be intimated to Ministry of Environment and Forests/State

Pollution Control Board.

D. The chemical additives used for the preparation of DF should have low

toxicity i.e. 96 hr LC50 > 30, 000 mg/l as per mysid toxicity or toxicity test

conducted on locally available sensitive fish species. The chemicals used

(mainly organic constituents) should be biodegradable.

E. DC separated from OBM after washing should have oil content at < 10

gm/kg for disposal into disposal pit.

F. The waste pit after it is filled up shall be covered with impervious liner,

over which, a thick layer of native soil with proper top slope is provided.

G. Low toxicity OBM should be made available at installation during drilling

operation.

H. Drilling wastewater including DC wash water should be collected in the

disposal pit evaporated or treated and should comply with the notified

standards for on-shore disposal.

I. Barite used in preparation of DF shall not contain Hg >1 mg/kg and Cd > 3

mg/kg.

J. Total material acquired for preparation of drill site must be restored after

completion of drilling operation leaving no waste material at site. SPCB

should be informed about the restoration work.

K. In case, environmentally acceptable methods for disposal of drill waste

such as (a) injection to a formation through casing annuals, if conditions

allow (b) land farming at suitable location (c) bio-remediation (d)



incineration or (e) solidification can be considered, in such cases oil

industry is required to submit proposal to Ministry of Environment and

Forests/State Pollution Control Board (MoEF/SPCB) for approval.

EIA for Exploratory Drilling in MZ-ONN-2004/1 NELP Block 3-1


CHAPTER 3: PROJECT DESCRIPTION

3.1 INTRODUCTION

The On-Shore NELP –VI BLOCK: MZ-ONN-2004/1 located in the Aizwal, Lunglei, Mamit and Serchhip districts of Mizoram has been allotted by Government of India to Oil India Limited (OIL) and M/S Shiv–Vani Oil & Gas Exploration Services Ltd. for exploration and production of hydrocarbons. OIL is the Operator of the block.

As per the Minimum Work Program (MWP) of the Production Sharing Contract (PSC)

signed with the Government of India, OIL is required to Drill 06 (Six) wells .Three locations have been identified for drilling. The other three locations will be selected after further geo scientific studies and data gathered from the drilled wells.

Salient features of the project :

Number of wells

Five (05) Nos. in phase I

One (01) No. in phase II

The above is as per MWP

Name and area of Block MZ-ONN-2004/1 and 3213 Km2

District(s) Aizawl, Mamit, Serchhip and Lunglei

Districts.

State Mizoram

Depth 4000 - 5500m ( tentative)

Estimated drilling Period 150 days (approx) for each well

Type of Hydrocarbon expected Oil/Gas

Cost of Project INR 300 crores (approx) for Six Wells

3.2 BLOCK MZ-ONN-2004/1 AREA

The block covers an area of 3213 km2 in the central part of the state. It starts from

about 5 kms South of Aizawl and ends 6 kms. East of Hnahthial Town, covering four

districts, viz. Aizawl. Sechhip, Mamit and Lunglei Districts. The coordinates are given

below.



POINTS LATITUDE LONGITUDE DEG MIN SEC DEG MIN SEC

A 23 40 00 92 32 54.85 B 23 00 00 92 35 58 C 23 00 00 93 00 00 D 23 40 00 93 00 00 A 23 40 00 92 32 54.85

Drilling Locations

Coordinates of the drilling locations which have been released are as follows:

Sl. No. LOCATION

CO-ORDINATES Easting Northing Longitude Latitude

1 OIL 2 3034138 650176 92o51’06.49” 23o35’00.87” 2 OIL 4 3009334 638426 92o36’23.21” 23o28’55.71” 3 OIL 5 3008350 635893 92o35’46.75” 23o27’33.99” 4 OIL 8 3027949 618948 92o47’04.69” 23o18’10.04”

3.3 JUSTIFICATION OF THE PROJECT

To determine the presence of hydrocarbons and to evaluate the recoverable reserves in

the Mizoram Block, 2D seismic surveys and other Geo-scientific studies have been

carried out. OIL is now planning to drill six (6) exploratory wells for obtaining more

precise estimate of expected total reserves of hydrocarbon and techno-economic

viability of Oil/gas production.

3.4 BENEFITS OF THE PROJECT

Commercially viable production of Oil / Gas from the block is likely to render the

following benefits

i) Economic assistance to the Govt. of Mizoram from more royalty.

ii) Employment potential for local people.

iii) Overall infrastructure development.

iv) Increase in business opportunities.

v) More assistance from OIL towards Corporate Social Responsibility (CSR).

vi) More cess to central Govt.

vii) Overall societal benefit.



3.5 DRILLING OF EXPLORATORY WELL

Introduction

To establish the presence of hydrocarbon and evaluate its commercial viability Oil/Gas

has to be flown from the underground hydrocarbon bearing reservoir to the surface.

This is achieved by drilling an oil well. OIL is planning to drill six (6) wells to

determine the hydrocarbon prospects and reserves. Drilling operations will be carried

out up to a depth range of 4000m to 5000m (approx). The lithological details at the

proposed drilling locations are expected to be as follows:

Tentative Stratigraphy of Mizoram area

Age Group Formation Intervals (m)

Lithology

Mio

cene

Surm

a

Upper Bhuban

Surface-1200

Thin bedded to massive s.st.

Middle Buhban 1200-3200

Grossly s.st with interlaminated silt st & shale.

Lower Bhuban 3200-4200 Thin bedded shales, s.st &

silt st.

Olig

ocen

e

Bara

il

Renji 4200-5000 Predominantly shale with thin beds of s.st & silt st.

Jenam 5000-6200 Dominantly carbonaceous shales, silt st & s.st.

Laisong 6200-7700 Thin bedded s.st, silt st, shales & carbonaceous shale.

Palaeocene-Eocene

Disang Group

Up. Disang

7700-11000

Predominantly thick unit of dark, indurated shale interbedded with occasional bands of s.st & L.st.

Lr. Disang

Pre-cambrian

Basement



3.6 OIL WELL DRILLING ACTIVITIES

Planning and execution of an exploratory drilling well involves the following activities:

Geo scientific data acquisition, processing, interpretation / analysis and release of

drilling location by Geo-science team.

Site survey and access road alignment (if any) - will be undertaken through

consultants/contractors.

Land acquisition and removal of vegetation- Necessary approvals and compensatory

afforestation etc through concerned forest department.

Access road and well site preparation by civil contractors.

Well design & Planning

Rig Selection

Oil well Drilling.

Production Testing.

Well site restoration.

Rig movement

SITE SELECTION

The location of the exploratory wells have been released by Geo-science department of

OIL based on the geo-scientific survey/studies. Thereafter, the site survey was carried

out by approved consultant/contractor and site was finalized considering the following

environmental factors:

At a reasonable distance (minimum 500m) from any river or stream.

Minimise cutting of trees and alteration of natural contours.

Avoid National Park/ Wild Life Sanctuary/ Eco-sensitive area.

Without affecting drainage

Avoid or minimize detrimental effects on the surrounding environment

The exploratory oil well drilling would be a short duration (about150days) activity at

each location.

SITE ACQUISITION AND SITE PREPARATION



A flat drilling site of about 2.781 hectares of land which is almost rectangular in

shape (175mX140m) would be required to accommodate the drilling rig and allied

equipment, effluent pit, flare pit, boiler, office bunk houses etc.Some additional land

would also be required for preparation of approach road.

WELL DESIGN & PLANNING

Before commencing drilling operations the following need to be designed and planned

taking into consideration the vital geo-scientific information

Type of well- (Vertical or deviated) & Total depth.

Well bore sizes & Casing setting depths, sizes and grades.

Drill string confugaration.

Drilling fluid (mud) and Hydraulics programme.

Cementing programme

Wire line logging programme.

Well testing programme.

Procurement of various consumables like bits, casing pipes, chemicals, cements etc.

3.7 RIG SELECTION

The Drilling Rig and allied equipment are selected as a package on the basis of total

depth of the wells to be drilled, geological formations, downhole pressures and

complications that are likely to be encountered. OIL is planning to deploy a suitable

2000HP Diesel- Electric AC SCR Rig. Schematic diagram of rig operation is given

below:



The Rig to be deployed would be required to have the following equipment and rating/

specification.

DRAW WORKS

- Input horse power (HP) rating - 2000 HP (minimum) with nominal depth rating

5500 m (minimum) with 5” OD drill pipes.

- Draw works will be operated by minimum two DC motors of GE-752 make or

equivalent.

MAST & SUB-STRUCTURE

Swing lift cantilever type self elevating mast & substructure with minimum clear

height of 147 feet. It will have a hook load capacity (derrick capacity) of 1,000,000

lbs (1000 KPS).Casing capacity 800,000lbs(apprx) simultaneously with 550,000lbs

of racked pipes. Substructure to have a clearance of minimum25 feet from ground

level to underneath of the rotary table beam.

ROTARY SWIVEL

Rotary Swivel to have a minimum API dead load rating of 500 Tons with 5000 Psi

working pressure (minimum).

TRAVELLING BLOCK

Unitized traveling block and hook assembly of 500 Tons capacity with 6 sheaves

grooved suitable for drill line and with minimum 12 lines operation.

POWER PACK

Engines minimum 4 (four) numbers turbocharged, after cooled, air start, diesel

driven, 1010 hp@1500 rpm. Generators – 1500 kVA (each), 600 V, 1500 rpm, 0.7

PF, 50 Hz.

SCR SYSTEM

One RIGHILL electrical SCR system

MUD PUMP



Two nos of triplex single acting mud pumps with input horse power rating of 1600

(minimum) each driven by 2 DC motors of matching HP rating or equivalent.

DRILL PIPES

A minimum of 6000 m of 5” OD drill pipe consisting of 19.5 PPF Grade ‘G’

flash/friction welded, tapered or square shoulder, in range 2 length.

DRILL COLLARS

Suitable size and numbers of Drill Collars to be used.

BOP CONTROL UNIT

Proper BOP (Blow Out Preventer) stack and associated Well Control Equipment (as

per applicable API specification) will be used for the drilling operation to contain

any unexpected pressures from the well.

TOTAL TANK VOLUME

A mud system having an active capacity of 220 m3 and gross capacity of about 400

m3, including reserve capacity will be used for drilling operation.

Emergency Systems – this includes fire & other hazard detection and protection

equipment. MBBS Doctor and an ambulance will be available at site for

emergency medical attention, round the clock.

Safety/protective appliances – all the personnel working in the drill site will be

provided with safety & protective appliances like helmet,safety boots,hand gloves

,goggles , etc. as per the OMR and other Govt. regulations.

Environmental Protection – Blow Out Prevention (BOP) system, drill cuttings

handling equipment, effluent pit with recycling arrangement and other facilities

which may be required for protection of environment will be in place.

SUPPORT SYSTEM

- Portable Living Quarters – to house essential personnel on site on a 24 hour

basis. These units are provided with Bath/Washroom.

- Crane-age – cranes for loading/off loading equipment and supplies.

- Vehicle requirement for inter location movement (ILM)- The Drilling rig

components including associated equipment etc comprise of about 90

truck/trailer loads.



TYPICAL DRILLING RIG AND ASSOCIATED SYSTEM

3.8 DRILLING OF OIL/GAS WELL

Well construction: Drilling wells are drilled in sections, with the diameter of each

section decreasing with increasing depth. The lengths and diameters of each section of

the well are determined prior to drilling through well design. The profile of a typical

well ( 5000m) is given below.

Hole Size

(Inch)

Casing Size

(Inch)

Depth of Shoe

(meters below rotary table)

26” 20” 0- 150

17-1/2” 13⅜” 0 - 900

12 -1/4” 9⅝” 0-3000

8-1/2” 7” 3000- 4200

5-7/8” 4-1/2” 4200-5000

Well spudding is the start of drilling activity. Top-hole section will be drilled to a

desired depth based on well design. After drilling top-hole section, it will be cased with

a pipe called "Casing". The casing provides support to the drill hole wall and secures

the hole-section. Other than this, it isolates problematic hole-sections such as loose

zones, shale sections, over pressurized formations, etc. After running casing, the space

between hole wall and casing (annulus) will be cemented. This process of drilling and

casing the hole-sections as per the well design until the final well depth ( target) is

achieved.



Drilling Fluid Plan

During drilling operations a fluid known as drilling fluid (mud) is pumped through the

drill string down to the drilling bit and returns between the drill pipe and hole / casing

annulus up to surface back into the circulation system after separation of drill cuttings /

solids through solids control equipment. Drilling fluid is essential to the drilling

operation and performs the following functions:

Cleans the bottom of the hole by removing the cuttings and carrying them to

surface.

Cools and lubricates drill bit and string.

Continuously builds a wall around the inside of the hole which prevents the hole

from caving in.

Counters natural formation pressures, preventing the uncontrolled flow of

oil, gas, or water into the borehole.

Holds cuttings and weight material in suspension, when circulation is stopped.

Supports part of the weight of drill pipes, casing ,tubing,etc.

Transmits hydraulic horse power to the bit.

Acts as medium for electrical well logging.

Ensures maximum information about the formations penetrated.

Prevents corrosion of tubulars

TYPE OF DRILLING FLUID (MUD)

An environment-friendly Water-Based Mud (WBM) system will be used for drilling

of the proposed wells.It may be noted that a typical WBM may contain nearly 80%

water and 20% clay plus chemicals by weight.

Some of the typical chemicals including several bio-degradable chemicals which are

planned to be used for the drilling campaign are as follows:



Chemicals Chemical Characteristics

- Barytes Inert

- Bentonite Clay

- CMC (H) Bio-degradable

- Guar Gum Bio-degradable

- PAC (SL) Bio-degradable

- CMC (SL) Bio-degradable

- CMC (L) Bio-degradable

- PAC (R) Bio-degradable

- XC-Polymer Bio-degradable

- Linseed Oil Bio-degradable

- EP-Lube veg-oil lubricant

- Drilling Det Bio Degradable

The above list of drilling fluid chemical requirements may vary considering situations

encountered during drilling. During the operation phase however, chemical usage will

be monitored and efforts will be made to conserve or reuse chemicals as much as

technically possible.



Mud Circulation & Solid Control System

The drilling fluid circulation system consists of several items of equipment as given

below:

The mud pumps take drilling fluid from tanks and pump the same to the bit through

drill pipes. The mud leaves the well bore through annulus and finally falls over the

shale shaker. The mud used during the operation will flush out formation cuttings from

the well bore which will be separated from the fluid using solids control system. This

will include shale shakers, desanders and. desilters. The process of reusing the drilling

fluid during drilling operation is commonly known as “closed loop system”. The

system is ideal for drilling operations in sensitive environments as it cuts down

immensely on the total water consumption for the formulation of drilling mud and also

saves on the consumption of the chemicals.

Special applications of Drilling Fluid

To overcome various types of well problems, specific components are added to the

mud to adjust the properties to ensure that following functions are met:



Fluid loss control: Bentonite as well as naturally occurring additives such as

starch and cellulose are added to the drilling mud to retard fluid loss to the

formation.

Lost circulation: Naturally occurring fibrous, granular or flaky materials are used

to stop lost circulation when the drill bit enters a highly porous or fractured

formation. Typical materials include sawdust, groundnut shells, mica etc.

Lubricity: Normally the drilling fluid is sufficient to lubricate and cool the bit.

However, under extreme loading, other lubricants such as EP lube, Linseed oil etc

are added to prevent the drill string from becoming stuck.

Shale Control: To control caving, sloughing etc of the well bore shale stabilizer

(e.g magcoasphasol) is used.

pH control: Caustic Soda is used to control the alkalinity of the drilling fluid in the

range of pH of 9 to 10. This ensures the optimum performance of the polymers in

the fluid and controls bacterial activity.

Pressure control: Barite is generally used as a weighting material to control down-

hole formation pressure and to prevent the ingress of formation fluid into well bore.

The essential ingredients of the WBM are all low toxicity materials, rated either as

Grade E products (according to the new OCNS grading system), or Grade O (according

to the former OCNS system). These are the two lowest toxicity categories. A variety of

other products will be available for various contingencies. Thinners such as chrome free

ligno-sulphonates (CFLS) and lignin compounds may be used to control rheology.

CEMENTING PROGRAM

Oilwell cementing is the process of preparing a slurry of API Class G cement with

water and various additives in required quantities as accelerators/ retarders, density

adjusters, dispersants, fluid loss additives, anti gas migration additives, etc. This slurry

is pumped down through steel casing to cover the critical points in the annulus around

the casing in the open hole.

Functions of the cementing process

Bond and support the casing strings

Isolate oil, gas and water bearing zones.

Protect fresh water bearing zone from contamination.



Prevent Blowouts by quickly forming a seal.

Seal off zones of lost –circulation or thief zones.

Protect casing from corrosion.

Protect casing from shock loads.

DRILLING RIG & EQUIPMENT LAYOUT

Suitable Diesel- Electrical 2000HP Rig will be used for drilling the proposed well.

Cellar of the rig will occupy nearly 2m x 2m and overall exploratory well plinth will be

nearly 2.781 hectares. Close to the rig, tanks for recycling of the drilling mud,

appropriate waste disposal facilities, suitable storage facilities for chemicals and diesel

fuel, office bunk houses etc will be arranged. A typical layout plan of OIL drilling rig

and associated facilities is enclosed.

WELL CONTROL - BLOWOUT PREVENTION

Well control procedures will be conducted as per API 6A and API RP 53 standards.

Well control occurs in two forms, namely, primary and secondary.

Primary: The influx of formation fluids is prevented by maintaining sufficient down

hole pressure with drilling mud of appropriate weight.

Secondary: This is applied when primary control has failed and fluids have entered the

well bore from a formation. The aim of secondary control is to safely discharge the

fluids at the surface while preventing further influx down the hole. This is achieved by

using blow out preventors (BOPs). A BOP stack is usually formed of three or more

separate hydraulically operated preventors, of which there are two main types:

Annular; and

Ram type.

The BOP stack arrangement is selected depending on the expected well pressure. Once

assembled, the stack is placed on the well mouth and pressure tested before

commencement of drilling.



A TYPICAL BOP STACK

DERRICK FLOOR



3.9 WELL EVALUATION

Conventional Coring

Conventional cores of sub-surface formations are taken on selective basis to carry out

Petrophysical and Geoscientific studies.

Well Logging

Wireline logging operations are undertaken with specialisd equipment mounted on

custom built trucks to provide information on the potential type and quantities of

hydrocarbons present in the prospective formations.

There are different well logging techniques including electric, electronic, sonic,

radioactive logging etc. Logging instruments (sensors) are attached to the bottom of a

wire line and lowered to the bottom of the well. They are then slowly brought back, the

devices reading different geoscientific parameters as they pass each formation and

recording the corresponding data on graphs, which can be interpreted by the exploration

team. There are no emissions to the environment associated with wire line logging

operations. The radioactive sources required for well logging operations will be kept in

specially designed containers, if used.

Well Testing

In the event that presence of hydrocarbons is detected in reasonable quantities, as

determined by wire line logs and other geoscientific techniques production testing of

well is undertaken. During testing, pressure control Christmas tree at well head is

installed and other well testing equipment are lined up to test the well in a controlled

manner. The main purpose of testing the exploratory well is to determine the quality,

quantity and commercial viability of oil/gas production. This is done by bringing a

controlled flow of well fluids (oil,gas,water) to the surface through a nozzle (called

Bean) of appropriate diameter in the flowline of the well.

Then the recovered oil/gas along with formation water will be flowed through the

piping system to the Separator and other production testing equipment. Hydrocarbon

gases will be flared in a suitably designed Flare Pit.



3.10 COMPLETION OF DRILLING

On completion of exploratory drilling activities wellsite restoration plan will be

prepared for the following two scenarios:

i) Commercially viable Hydrocarbons are discovered

In the event that economic quantities of hydrocarbons are found, the well will be shut in

with a wellhead / X-mas tree in place, but all other equipment and materials will be

removed from present location to the next drilling site. At the end of well testing at

each drilling site, the HDPE Lined Secured Pits for Drill Cuttings and Drilling Mud

will be covered with a top HDPE lining. The pit will then be backfilled with minimum

300 mm layer of soil.

ii) Economic Quantities of Hydrocarbons are not Found

In the event that economic quantities of hydrocarbons are not found an abandonment

plan will be implemented for the drilling sites in accordance with the applicable Indian

regulations, OISD , Oil Mines Regulation(OMR) etc. Plugging requirement of

abandoned wells as per Oil Mines Regulation, 1984 are as follows: When it is intended

to abandon a well.

1. All permeable formations shall be isolated with cement

2. A cement plug of minimum length of 50 m shall be placed at the bottom of the well

3. A cement plug of a minimum length of 50 m shall be placed across the shoe of

surface casing

4. The cellar pit around the well shall be filled up and the land shall be restored to the

original level

5. Cased wells may be abandoned by placing a bridge-plug above the top of

perforations capped with three-metre cement plug.

6. Every abandoned well shall be clearly identified at site.

In addition to the above, guidelines as advised by MoEF, New Delhi and SPCB,

Mizoram shall also be followed.

The overriding principle is that the environment should, with time be reinstated broadly

to its original condition. Until such time as this is achieved, OIL would actively manage

the reinstatement process.



3.11 RIG DEMOBILIZATION

Demobilisation would involve dismantling of the drilling rig, all associated equipments,

campsite etc and transporting it out of the last drilling location. Demobilisation process

is expected to take about 20 to 30days (Approx) and would require about 90

truck/trailer loads.

3.12 MANPOWER AND OTHER REQUIREMENTS

Manpower Requirement

Under normal operation, the project work force will consist of nearly 65 persons

distributed as follows:

Location Manpower Total Technical Non-Technical

Base Office 5 -- 5 Camp Office 20 10 30 Well Site 20 10 30

Total 45 20 65 Workers will be required to work in 2 shifts on 12-hour basis. At any one time there

will be nearly 30 persons at the well site and will be accommodated at the temporary

camp/area facilities near the well site. A catering company will be contracted to provide

the messing facilities.

Vehicles Requirement

The following type of vehicles will be required during drilling and testing operations

for movement of men and material as detailed below:

Sl. No. Vehicle Number Purpose 1. Ambulance 1 Standby at site for emergency. 2. TATA Sumo or

equivalent 1 For meeting domestic requirements of

the camp site personnel. 3. Truck 1 For transporting cement, chemicals,

etc to well site as and when required from base camp godown.

4. Trailer 1 For transporting casing pipes, tubulars, other heavy equipment to well site from base camp godown.



Time Requirement

Time required for actual drilling and completion of one well upto a depth range of 4000

m to 4500m will be nearly five months (150 days).In addition, about 15 to 20 days may

be required at each well site for rig & equipment assembling before commencement of

drilling and dismantling after completion of drilling..

Water Requirement and Water Balance

The water requirement during drilling of exploratory well will be small and is likely to

range from 30 to 50 klpd with an average of 40 klpd. Water usage and water balance

are as follows:

Item Inflow Loss

klpd

Outflow

Amount

klpd

Basis Amount

klpd

Disposal

WBM Make-up 10.0 Assumed 5.0 5.0 Effluent Pit

Fire Water Make-

up/Equipment/Floor

Washing and Other

Uses

20.0 Assumed 7.5 12.5 Effluent Pit

Domestic 4.0 For 40

persons

@ 100

lpd per

person

1.5 2.5 Waste Water &

Sewage Disposal

Facilities/Soak Pit

Storage and Other

Losses

6.0 Assumed

@ 15%

6.0 -- --

Total 40.0 20.0 20.0

Water requirement during production testing period will be very small and may not

exceed 10 klpd



Source of water

Water for drilling and testing will be supplied by road tankers from nearest sources to

drilling site without affecting competitive users.

Power Requirement

Drilling rig and associated systems will have 4 DG sets, each of 1000 hp (or 750 kW)

to meet the total power requirement including drill site & campsite requirement during

drilling. A 50 kw DG set will be used to meet power requirement during well testing

operations.

Fuel Requirement

High speed diesel (HSD) requirement will be nearly 3 to 5 klpd during drilling and 1 to

2 klpd during well testing for the operation of drilling rig and to meet other power

requirements at drilling site as well as for vehicles used for transport of personnel and

material. Diesel will be stored at drilling site in covered MS tanks of 20 to 30 kl

capacity. Only low sulphur (<0.05%) HSD will be used.

Chemical Requirement

Various chemicals that are likely to be used have been listed in Drilling Fluid Plan

section. At the planning stage, an estimate of the potential usage for every chemical

will be made. During the operation phase chemical usage will be monitored and efforts

will be made to reduce or conserve chemical consumption as much as technically

possible. Bentonite and barite will be stored in sheds while expensive chemicals

required in smaller quantities will be stored in godowns.

Storage of Supplies

The supplies during well drilling and testing include all fuels and oils, chemicals for

drilling mud, spare parts for the rig and vehicles, and food and other supplies for the

camp site. Fuels, oils, and chemicals will be unloaded in designated areas with

impermeable floors (either concrete or covered with an impermeable material) and

lined by dykes or walls to prevent soil and water contamination from spills.

Material Supply System

Supply of materials, such as, diesel fuel, drilling chemicals, provisions and other

supplies to the drilling site will be made by road transport. Road tankers will be used



for supply of diesel fuel to storage facilities at drilling site. Provisions and other

supplies to drilling site will be made by light vehicle. Road transport will also be used

for supply of materials and transport of personnel to drilling sites.

3.13 EXPLORATORY DRILLING POLLUTION SOURCES

During drilling and testing of oil/gas at exploratory locations it is unavoidable that there

will be requirement for the discharge of waste materials to the environment. The

sources and types of wastes that may be generated are noted in the following sub-

sections.

Waste generation during drilling operation

Solid waste - Nearly 130-150m3 of drill cuttings comprising of clay, sandstone shale,

etc. are expected to be generated in the course of drilling of the well. The drill cuttings

will be retained in the cuttings retainer pit

Liquid waste- Nearly 50 to 75 m3 of wasted WBM is expected to be generated during

drilling operation. The same will be disposed in the HDPE lined effluent pit within the

drill site area.

Drainage Discharges

Drainage discharges will occur from a variety of sources .These include:

Cleaning at derrick floor area

Machine area floor drains;

Cleaning of shale shaker screens

General washing/cleaning in the labs, offices, etc.

Domestic Waste Water

Domestic wastewater will be generated by general use by work force during drilling

and testing operations at the exploratory well site. As part of the site preparation stage,

a drainage and sewerage system will be constructed for the camp and the rig. The

sewerage system will consist of soak pits for the collection and treatment of wastewater

from the camp kitchen, laundry, and showers. Soak pits will be constructed in such a

manner so as to avoid any seepage in any surface or ground water source.

Gaseous Emissions

Emissions generated in a drilling site will consist of the following:



Exhaust gases from the diesel driven power generators - will include SPM, CO2,

NOx, SO2, CO and unburnt hydrocarbons (UHC). HSD with low sulphur content

(<0.05%) will be consumed during drilling operation. Exhaust emissions will be

discharged from stacks of appropriate heights (5 m or more) for adequate natural

dispersion from DG sets.

Emissions from flaring of hydrocarbons during well testing - will release NOx,

CO2, and SO2. Flare gas quantity will depend upon the extent of gaseous hydrocarbons

generated during approximately 5 to 10 days period of testing of oil and gas at each

exploratory location. About 10000 m3/d of associated gas is likely to be flared for about

3 to 4 days at one well.

Exhaust fumes & dust emission from vehicles –movement of about 3 to 4 passenger

and heavy vehicles in a day is not likely to have any adverse impact on the

environment.

Miscellaneous Emissions - Minor gaseous releases may occur from venting of the

tanks, such as, test tank & oil storage tank. Small methane releases may also occur in

association with water based mud sediments and it will be released to the atmosphere.

Unless significant quantity of methane is released, even on a calm day, it will not

constitute a viable combustion hazard because lower flammability limit for methane in

air is 5%.

Noise

Sources of noise at the drilling site include :

- Diesel powered generators

- Rig pumps

- Rotating equipment such as electric motors, mud tank agitators, rotary table, draw

works, etc.

Noise level at the periphery of the drilling well plinth will not exceed 75 dB (A) and

will decrease rapidly on moving away from the well site. . Vehicular traffic on access

road is expected to generate temporary noise level of less than 70 dB (A) at about 10 m

distance.



Heat Generation

The drilling work will generate heat which will be dissipated to the WBM (about 500C

at surface) and then to the atmosphere. Hence it is unlikely to have any noticeable

effect in the area surrounding the drilling rig.

3.14 TREATMENT AND DISPOSAL STRATEGY FOR POLLUTANTS

Drilling Discharges

Drill Cuttings

The accumulation of drilled cuttings at the drilling site is unavoidable in any drilling

operation. Rock/drill cuttings generated during drilling will be carried to surface with

drilling mud where they will be separated from the drilling fluid and cleaned followed

by Solar drying. On completion of drilling approximately 130 to 150 m3 will be

generated. Attempt is always made to use these cuttings for well plinth/road

maintenance, landfill etc. The remaining quantity of cuttings will be placed in HDPE

lined impervious effluent pit, covered with HDPE sheet and then with compacted

cover of soil and capped as per regulatory pit closure protocol.

Wasted WBM

About 50 to 75 m3 of WBM is likely to be wasted at each drilling site. Due to moderate

to heavy rainfall and humid climate solar drying may not be always possible. Since it is

non-toxic, it will be diluted with water and disposed off in HDPE lined mud pit. Pits

will be constructed of sufficient capacity to provide safe storage and prevent

contamination of surface and ground water. Subsequently, the diluted mud will be

treated in the ETP and treated water shall be disposed off suitably.

Waste Water Recycling

Wastewater from drilling rig drainage discharges and rainwater will be sent to a settling

pit, where suspended solids in wastewater will settle. The supernatant will be drained to

the second pit for further settling of suspended solids. Subsequently, the supernatant of

the second pit will be drained into the third pit. Most of this water will then be reused in

washing, process operations, dust suppression, etc.



Domestic Waste Water

Domestic waste water disposal for residential facilities at the well site will be handled

in a well designed drainage and sewerage system.

Used Oil

Spent oil generated from oil changes or leakage from equipment or diesel storage tanks,

used lubricating oil (from engine oil changes) is designated as hazardous and shall be

disposed as per approved guidelines of MOEF.

Medical Waste

Small amounts of medical waste like used syringes, bandages, empty medicinal bottles,

etc. This waste will be treated as per CPCB Guidelines.

Camp and Sewage Waste

All biodegradable waste (food, kitchen waste etc) will be disposed off into small humus

pits in campsite area away from use by rig crew members. The pits are to be covered to

avoid any odour nuisance and check contact with flies or insects. The sewerage system

will consist of soak pits for collection of waste water from the camp kitchen, laundry

and showers .Sewage from toilets will go into septic tanks.

Gaseous Emissions

The exhaust gases from diesel driven power generators and diesel-powered equipment

on the rig will be discharged through stacks of appropriate heights (5 m or more) to

achieve adequate natural dispersion. Only low sulphur (<0.05%) HSD will be used.

Gaseous hydrocarbons produced during testing will be flared in a multiheader flare pit

at a distance of about 90m from well centre. Ground flare will be properly designed and

will be surrounded by heat resistant wall as shown in figure enclosed.

Small methane releases from drill cuttings and mud sediments at the WBM

recirculation tank will rise to surface and will readily transfer to the atmosphere without

constituting a viable combustion hazard.

Noise

Noise level at the periphery of drilling location plinth does not exceed 75 dB.



Heat Generation

Natural heat losses from recirculating WBM will rapidly dissipate the heat generated

due to drilling operation to a large mass of WBM and to the atmosphere.

Potential Accidental Events

Due to observation of necessary safety requirements as per OMR,OISD and other

regulations chances of accident occurring are negligible. However, in all aspects of

hydrocarbon exploration, there is always a risk of non-routine or accidental events such

as

Occurrence of blow out

Occurrence of sour gas (H2S)

Blow out followed by ignition can be extremely hazardous. Sour gas (H2S) may also be

released from the well along with gaseous hydrocarbons.. However, it is known that

crude oil/gas in this region is sweet in nature, i.e there is no presence of H2S in

produced oil/gas.

Spillage of diesel fuel is neglibile from storage facilities at the drilling site.

A brief account of these hazards and general safety measures likely to be adopted

during drilling and initial testing of the exploratory well is presented in Chapter 6 of

this report.

3.15 ANALYSIS OF ALTERNATIVES

Site Alternative

The precise location of a vertical well is dependent upon the characteristics of the

underlying geological formations on complete analysis of seismic survey data and other

relevant information by OIL.

However, in case of logistic problems and other reasons the area from which the

prospect can be drilled is restricted to a radius of about 500 m.

Technical Alternatives

The approach followed in executing the exploratory drilling and testing programme has

been to adopt cost effective and environment friendly drilling and testing programmes

and equipment.



CHAPTER 4: BASELINE ENVIRONMENTAL CONDITIONS:

PHYSICAL, BIOLOGICAL, DEMOGRAPHIC AND

SOCIO-ECONOMIC

4.1 INTRODUCTION

The field studies were carried out in and around the block MZ-ONN-2004/1

for a period of nearly 5 weeks from 24th March’2011 to 30th April’2011 for

the Rapid Environmental Impact Assessment (REIA) studies to get necessary

baseline data for the present environmental scenario in the study area.

4.2 SAMPLING/MONITORING LOCATIONS

Baseline primary data collection was carried out within the block area as

indicated in Sub-section 1.4.3.2 B (I) in Chapter 1. Baseline

sampling/monitoring was carried out as tabulated below:

Baseline sampling/monitoring was carried out as tabulated below:

Parameter Location

Soil Serchhip, Khwalailung, Buarpui, Thenzawl, Chhingchhip,

Tlungvel, Aibawk and Sialsuk Fig-4.1

Water Tap: Aibawk and Serchhip

River: Turial, Tlawng GPS Map in Fig-4.3

Ground Water : GPS Map in Fig-4.3

Ambient Air 10 location GPS Location Map in Fig-4.2

Noise 10 location GPS Location Map in Fig- 4.3

4.3 PHYSICAL ENVIRONMENT

4.3.1 Topography and Physiography

The block MZ-ONN-2004/1 falling in Mamit, Aizawl, Serchhip and Lunglei

districts of Mizoram having a total area of 3213 sq. km is covered with hilly

terrain and is forested. Most of the area falls under reserve forests. The rivers

Mat, Tuirial, Tuikum, Tut, Tlawng and Tuichang flow through the block area

and are perennial. The area is interspersed with nullahs which are dry in winter

and have fordable rain water during monsoon. The area is undulating with

topographic lows and highs with elevations reaching approximately upto 1500

m above mean sea level. Some agricultural fields can be found in plains



section of the block area and the population is thinly dispersed in small towns

and villages across the area generally close to roads. The Khawanglung

Wildlife Sanctuary having an area of 35 sq. km is located in south-eastern part

of the block. The proposed area is well connected by a network of all weather

roads which generally run from north to south.

4.3.2 Soils

The block area has soils derived from siltstones, shales and sandstones of the

Surma and Barail groups. Soils which are derived from sandstone are usually

coarse textured, deep and permeable while those derived from shales and

siltstones are medium to heavy-textured, moderately deep or shallow and are

moderately to slowly permeable. Soils are non-calcareous, acidic and rich in

organic carbon. The available phosphate content is usually low. The content of

available potash is medium.

To understand the soil quality in the study area, soil samples were collected

from 8 villages/towns of the block. The soil sampling locations are shown in

Fig. 4.1. Composite soil sampling (10-15 cm depth) was carried out at each

location.

The value of important physical and chemical parameters of these soil samples

are given in Table 4.1. From the tabulated values, the following conclusions

can be made about the physical and chemical characteristics of the soil

samples.

A. Physical Parameters

The important physical characteristics of soils are bulk density, moisture

content, water holding capacity and texture. The results of analysis are given

in Table 4.1 and brief summary of physical characteristics are given below:

Moisture Content: Moisture content of soils of the study area ranges from 2.4

to 3.1%.

Bulk Density: Bulk Density of soils in the study area is found to be in the

range from 1.14 to 1.36 g/cm3.

Water Holding Capacity (WHC): Water holding capacity (WHC) of soil

samples of the study area ranges between 31.4 to 33.6 percent and these soils

are capable of retaining sufficient water quantity during rainfall for facilitation

of plant growth.



Texture: Soil samples from all locations are loam to sandy loam in texture.

B. Chemical Parameters

The results of important chemical parameters of soils of the block and

surrounding areas are also given in Table 4.1 (annexure II) and a brief

summary of chemical characteristics are given below:

pH: pH was determined by taking 1:5 ratio of soil and distilled water. pH of

soils in the study area is found to be slightly acidic (pH 5.5 to 6.5) to neutral

(pH 6.5 to 7.5) in the range of 6.4 to 6.9.

Calcium: Soluble calcium is a highly essential nutrient to plants and affects

the activities of certain enzymes. The soluble calcium content as Ca in the soil

samples of study area is found to be in the range of 11.2 to 20.0 mg/100g.

Magnesium: Soluble magnesium is used in plant growth in appreciable

amount. It is also active in enzyme system and has a vital part in

photosynthetic process. Soluble magnesium content as Mg in the soil samples

of study area ranges from 3.9 to 6.3 mg/100g.

Chloride: The role of chloride in plant metabolism is not established but the

presence of minute amount of chloride ion is essential. Soluble chloride

content in soils of the study area is found to be in the range of 15.6 to 19.9

mg/100g.

Alkalinity: Total alkalinity as CaCO3 of soil samples of the study area ranges

from 110 to 150 mg/100g.

Available Phosphorous: Available phosphorous as PO4 of soil samples of the

study area is high (>2.99 mg/100g) and ranges from 3.6 to 7.8 mg/100g.

Phosphate is an essential nutrient for agricultural production.



Sulphate: Soluble sulphate content in soil samples of the study area as SO4 is

found in the range of 4.5 to 7.7 mg/100g.

Potassium: Potassium content as K in soil samples varies from 11.7 to 29.7

mg/100g and soil can be categorized to have high K (>11.12 mg/100g).

Availability of potassium in soil is essential for agricultural production.

Total Kjeldahl Nitrogen (TKN): TKN concentration in soil samples varies in

the range of 0.075 to 0.118%. Availability of nitrogen in soils is one of the

main factor in agricultural production.

Total Organic Carbon (TOC): Total organic carbon content in soil samples

of the study area is found to be low (<0.5%) in the range from 0.20 to 0.23%.

Total Organic Matter (TOM): Total organic matter content in soil samples

of the study area is found to be in the range of 0.34 to 0.40%. It may be noted

that higher organic carbon content in soil shows higher microbial activities

and higher availability of nutrients to crop.

Cation Exchange Capacity (CEC): CEC value in soil samples is found to be

in a range of 9.25 to 15.54 meq/100g and indicates very low (CEC <10

meq/100g) to low (10 to 20 meq/100g CEC) productivity.

Conclusions: Soils of the study area have low fertility but are suitable for

cultivation.

4.3.3 Water Resources And Water Quality

4.3.3.1 Water Resources

Water resource of the study area is classified into following categories:

a) Surface Water Resources: River, nadi, nullah, ponds, etc.

b) Ground Water Resources: Accumulation of water in deeper strata of

ground.

The only source of recharging for surface water and ground water is from the

atmospheric precipitation, which is in the form of rainfall.

4.3.3.2 Rainfall in the Study Area

The monthly rainfall data from 2007 to 2009 are given for Aizawl, Mamit and

Lunglei and Serchhip in Table 4.2.Tabulated data shows that the annual

average rainfall for the period was as high as 3429.2.5 mm at Lunglei and as

low as 1486.52 mm at Serchhip. The study area generally receives maximum



rainfall during June and July (nearly 30 to 41% of annual rainfall) from south-

west monsoon, but it may be observed that rainfall is fairly good throughout

the year except for three months of winter season from December to February

which account for only about 0.07 to 1.7% of annual rainfall. The study area

can be categorized as heavy rainfall area.

Table 4.2:DISTRICTS–WISE MONTHLY AVERAGE RAINFALL DURING 2007-2009 (in mm)

Sl. No.

District Year Jan Feb Mar April May June July Aug Sept Oct Nov

Dec

1 Aizawl

2007 0.0 73.37 18.50 283.25 321.97 508.03 341.47 376.80 605.30 130.80 107.45 10.00

2008 36.65 44.75 30.78 107.53 248.46 256.18 262.98 343.78 327.25 101.40 30.50 0.0

2009 0.0 1.38 26.78 152.47 169.65 219.50 279.05 426.25 223.53 168.53 9.50 0.0

2 Lunglei

2007 0.0 47.10 28.33 160.93 378.00 558.83 548.86 584.86 813.43 229.10 86.03 0.0

2008 61. 67 9.43 19.00 19.00 186.00 256.37 393.00 498.37 328.70 88.77 16.77 0.06

2009 0.0 0.0 0.0 86.80 102.37 398.63 502.67 539.33 431.13 163.73 89.33 0.0

3 Mamit

2007 0.0 37.33 76.50 266.66 348.50 425.33 349.36 411.16 605.66 207.83 67.00 0.0

2008 48.25 13.50 105.00 279.50 242.00 223.75 647.25 216.00 285.50 257.00 0.0 0.0

2009 2.33 0.17 48.50 297.67 206.50 379.67 289.47 577.53 549.33 252.91 58.00 0.0

4 Serchhip

2007 0.0 58.50 12.50 270.00 348.00 524.50 446.00 372.50 485.50 303.55 121.50 0.0

2008 94.50 7.50 27.00 27.00 194.50 219.00 330.52 478.02 346.35 131.95 31.00 0.0

2009 0.0 0.0 13.00 66.40 147.00 258.04 292.06 420.40 120.40 126.00 34.02 0.0

SOURCE: Meteorological Data of Mizoram for the Year 2009 published by the Directorate of Economics & Statistics,Mizoram.

4.3.3.3 Surface and Ground Water Resources

Plate:4:1 Women carrying water in Cart

In Mizoram Life revolves around availability of Water. The Tuirial, Mat,

Tuikum, Tut, Tlawng and Tuichang rivers along with many nullahs are the

major surface water sources in the block and study area. All of them are north



flowing river having high gradient in bed rock channel without alluvial

development and virtually nonexistent of flood plain which leads to none

retaining of water around river. There is Surface water in the river in the rainy

season and they are virtually dry in the lean seasons.

Ground water availability in the study area is scares due to

1. Due to High relief ,the surface runoff is not retained

2. Deep topographic gradient facilitate quick and fast transfer of surface

runoff.

These factors inhabit retaining and replenishment of ground water.

There is shortage of water in the region. The People in the region rely on water

harvesting and water supply by the government agencies.

Tap water supply (river water) is available in the villages/locality for few

hours in a day through common taps. In the absence of tap water supply

villagers commonly use water from spring and river for drinking and other

domestic use.

4.3.3.4 Water Quality In Study Area

A. Introduction

Under natural conditions, surface water quality reflects environmental

conditions to a great extent. Hydro-geochemical factors influence color, odour,

taste, temperature and the degree of mineralization of water derived from

surface run off, springs, etc. Besides, human settlements, overall land use,

morphology of the basin area, seasonal distribution of rainfall and winds,

disposal of industrial effluents and sewage, etc. contribute a great deal in

determining the quality of water.

The quality of ground water is influenced by surface and sub-surface

environmental conditions. The quantity and quality of water entering the

underground regime is another important parameter which influences

underground water quality. Rainfall absorbs atmospheric pollutants during its

descent through the atmosphere.

B. Characteristics of Water Samples

The collected water samples were analyzed for selected physical and chemical

parameters. Table 4.3 (annexure III) gives the results of water quality

analysis.



D. Conclusion

Water, both surface and ground, quality in the block and surrounding area is

extremely good because all parameter values for all water samples meet

desirable limits wherever specified.

4.3.4 Climatology and Meteorology

4.3.4.1 Introduction

The meteorological parameters play a vital role in transport and dispersion of

pollutants in the atmosphere. The collection and analysis of meteorological

data, therefore, is an essential component of environmental impact assessment

studies. The long-term and short-term impact assessments could be made

through utilization and interpretation of meteorological data collected over

long and short periods.

Since the meteorological parameters exhibit significant variation in time and

space, meaningful interpretation can only be drawn through a careful analysis

of reliable data collected very close to the site.

Climatological (long-term) data is obtained from the closest India

Meteorological Department (IMD) station or from any other nearby station

which has been collecting meteorological data.

Aizawl meteorological station is the closest IMD station and is located at a

distance of nearly 5 km in northern direction from the northern boundary of

the block MZ-ONN-2004/1. Aizawl IMD station is collecting meteorological

data since December 1937. Climatological data of Mizoram is sourced from



Meteorological Data of Mizoram for the Year 2009 published by the

Directorate of Economics and Statistics, Mizoram

4.3.5 Ambient Air Quality


To get an idea of baseline air quality scenario in the study areas eight ambient

air quality monitoring (AAQM) stations were selected as described in Section

4.2. AAQM locations were largely based on settlement population in different

direction and distance to cover the entire block area.

Fig. 4.1(Annexure IV) indicates the locations of AAQM stations.

4.3.5.2 Methodology of Monitoring and Analysis

Polltech PM2.5 & PM10 Fine Dust Sampler was deployed for ambient air

quality monitoring and monitoring was carried out for three days at each

AAQM station in view of topography of the area and distances involved. The

Fine Dust Sampler has been located at ground levels where suitable concrete

slab roof top was not available at any location in the study area. The VOC and

the Methane was collected with hand held portable equipments.

Bureau of Indian Standards codes 1S-5182, parts 2, 4, 6 and 14 were used for

collection and analysis of samples.



4.3.5.3 Ambient Air Quality

The results of 24-hourly SO2, NOx, PM2.5 and PM10 concentration

measurements during the study period are presented in Table 4.4. On the basis

of tabulated data following observations can be made.

4.3.5.4 Particulate Matter (Size less than 10 m) PM10

The 24-hourly PM10 concentration at all AAQM locations is fairly low and

varies in a range from 29 to 42 g/m3. Highest 24-hourly concentration of 42

g/m3 is observed at Keifang town. Average 24-houly PM10 concentration is

highest at Keifang town (35 g/m3)

B. Particulate Matter (Size less than 2.5 m) PM2.5

The PM2.5 24-hourly concentration at all AAQM locations is fairly low and

varies in a range from 22 to 32 g/m3. Highest 24-hourly PM2.5 concentration

of 32 g/m3 is observed at Thiak.

C. Sulphur Dioxide (SO2)

The 24-hourly concentration of SO2 at all AAQM locations is quite low and

varies in a range of 7 to 15 g/m3. Highest average SO2 value of 15 g/m3 is

observed at Tlungvel.

D. Nitrogen Oxide (Nox)

The 24-hourly concentration of Nox at all AAQM locations is quite low and

varies in a range of 7 to 12.0 g/m3. Highest 24-hourly average Nox value of

12 g/m3 is observed at Tlungvel.

G. Methane (CH4)

Concentration of grab sample of CH4 for all AAQM locations is BDL in all

the locations

E. VOC (Volatile Organic Carbon)

The concentration of Volatile Organic Carbon in the study area varies in a

range of BDL to 2 ppm.

4.3.5.5 Ambient Air Quality Status



National ambient air quality standards for PM2.5, PM10, SO2, and Nox are

given in Table 4.4 and the Hydrocarbon and VOCs in Table 4.5

TABLE 4.4: AMBIENT AIR QUALITY IN MIZORAM BLOCK

Sl. No. SAMPLING LOCATION

Observed Value in µg/m3

PM10 PM2.5 SO2 NOx

Mean Max Mean Max Mean Max Mean Max

1

KEIFANG (A1) N 230 40 8” E 920 57 46”

35 42 24 28 10 13 7 10

2

KEIFANG (A2) N230 40 26” E920 57ˊ44” 34 36 23 26 11 12 8 9

3 KEIFANG(A 3) N230 39ˊ45” E920 57ˊ 38”

32 34 22 24 11 14 7 11

4 TLUNGVEL (A 4) N230 36ˊ24” E920 51 13”

31 33 24 26 12 15 7 10

5 TLUNGVEL (A 5) N230 36 47” E920 51 18.6”

30 32 26 28 9 11 8 12

6

DARLUNG (A 6) N230 27 47” E 920 36 20” 28 31 24 27 10 12 7 11

7 DARLUNG (A 7) N230 27 46” E92036 20”

27 29 22 28 11 11 7 11

8 S SABUAL (A8), N 230 26ˊ 59” E 920 35ˊ57”

26 32 23 29 9 12 8 12

9 THIAK (A 9) N230 28ˊ30” E920 42ˊ45”

28 34 26 32 10 11 9 11

10

SIALSUK(A 10) N230 24ˊ10” E920 44 ˊ52”

32 36 22 26 9 11 7 12

11 THENZAWL N 230 17 24" E 920 46 59"

32 35 21 24 9 12 8 11



TABLE 4.5: AMBIENT AIR QUALITY IN MIZORAM BLOCK

Sl. No. SAMPLING LOCATION

Observed Value in ppm

VOC CH4

1

KEIFANG (A1) N 230 40 8" E 920 57 46"

BDL BDL

2

TLUNGVEL (A 4) N230 36ˊ24" E920 51 13"

2 BDL

3

DARLUNG (A 7) N230 27 46" E92036 20"

BDL BDL

4

S SABUAL (A8), N 230 26ˊ 59" E 920 35ˊ57"

1 BDL

5 THIAK (A 9) N230 28ˊ30" E920 42ˊ45"

BDL BDL

6

SIALSUK(A 10) N230 24ˊ10" E920 44 ˊ52"

BDL BDL

4.3.6 Ambient Noise Levels


Noise can be defined as an unwanted sound. It interferes with speech and

hearing and if intense enough can damage hearing or is otherwise annoying.

The definition of noise as unwanted sound implies that it has an adverse effect

on human beings and their environment. Noise can also disturb natural

wildlife and ecological system.

4.3.6.2 Methodology

To understand the noise environment in the study area, a noise survey was

conducted using Sound Level Meter 100 manufactured by Envirotech , New

Delhi. Noise measurements were carried out at eight locations as described in

Section 4.1.2.



4.3.6.3 Equivalent Sound Energy Level or Leq

In most of the acoustic environments, the sound pressure level fluctuates with

time due to changes in noise generation sources. The fluctuating noise levels

are reported as equivalent sound energy level or Leq. It is defined as the

steady sound pressure levels which would have given the same total energy as

the actual time varying sound pressure level over the given time period.

4.3.6.4 Ambient Air Quality Standards in Respect of Noise

Ministry of Environment and Forest has notified the ambient standards in

respect of noise and these standards are given in Table 4.5.

Table 4.5 Ambient Standards In Respect Of Noise

Area Code

Category of Area Leq. Limits in dB(A)

Day Time Night Time

A Industrial Area 75 70

B Commercial Area 65 55

C Residential Area 55 45

D Silence Zone 50 40

Note: 1. Day time is reckoned in between 6:00 a.m and 10:00 p.m.

2. Night time is reckoned is between 10:00 p.m and 6.00 a.m.

3. Silence Zone is defined as areas upto 100 m around such

premises as hospitals, educational, institutions and Courts. The

Silence Zones are to be declared by the competent authority.

Source: Pollution Control Acts, Rules and Notifications Issued Thereunder, Central Pollution Control Board, Delhi, May 1998.

Ambient standards in respect of noise both for Lday and Lnight with respect to

noise applicable for residential area during day-time [55 dB(A)] and night-

time [45.0 dB(A)] are met at all locations.



TABLE 4.5 (a) NOISE LEVELS IN STUDY AREA

Sl. No.

Location Leq in dBA (Day time) (0600 to 2100 hrs)

Leq in dBA (Night time) (2100 to 0600 hrs)

1 KEIFANG (A1) N 230 40 8" E 920 57 46"

43.8 40.2

2 KEIFANG (A2) N230 40 26" E920 57ˊ44"

50.9 38.8

3 KEIFANG(A 3) N230 39ˊ45" E920 57ˊ 38"

48.9 37.2

4 TLUNGVEL (A 4) N230 36ˊ24" E920 51 13"

42.5 39.6

5 TLUNGVEL (A 5) N230 36 47" E920 51 18.6"

52.4 39.5

6 DARLUNG (A 6) N230 27 47" E 920 36 20"

46.2 38.1

7 DARLUNG (A 7) N230 27 46" E92036 20"

44.6 38.9

8 S SABUAL (A8), N 230 26ˊ 59" E 920 35ˊ57"

42.6 40

9 THIAK (A 9) N230 28ˊ30" E920 42ˊ45"

43.8 41

10 SIALSUK(A 10) N230 24ˊ10" E920 44 ˊ52"

45 38

11 THENZAWL N 230 17 24" E 920 46 59"

54 42

4.3.6.5 Land Use

4.3.6.6 Land Use: Scope And Limitations

The land use pattern indicates the manner in which parts of land in an area is

being utilized or non-utilized. It is an important indicator of environmental

health, human activity and a degree of interplay between these two. Even

though the soil quality, water availability and climate have strong influence on



the state of agriculture and vegetation, but the human activity may alter the

natural environment to large extent to suit human needs. Unsuitable land use

often triggers rapid environmental deterioration and disturbs ecological

balance.

FIG 4.1: LOCATION MAP OF PROPOSED LOCATION E

92º51´06.49″ N 23º 35´00.87″



FIG 4.2: ETM E 92º51´06.49″ N 23º 35´00.87″



FIG 4.3: LANDUSE CLASSES AROUND THE PROPOSED

PROJECT SITE AS INTERPRETED FROM SATELLITE DATA



FIG 4.4 : LOCATION MAP OF PROPOSED LOCATION 3

E 92°42’20.01” N 23°29’17.12”



FIG 4.5 : ETM 4 AROUND 10 KM RADIUS PROPOSED

LOCATION 3 E 92°42’20.01” N 23°29’17.12”



FIG 4.6: LOCATION MAP OF PROPOSED LOCATION 4 (E

92°36´23.21″ N 23°28´55.71″) AND LOCATION 5 (E 92°35´46.75″

N 23°27´33.99″)



FIG 4.7: ETM 4 LOCATION 4 (E 92°36´23.21″ N 23°28´55.71″)

AND LOCATION 5 (E 92°35´46.75″ N 23°27´33.99″)



FIG 4.8: LANDUSE CLASSES AROUND THE PROPOSED PROJECT

SITE AS INTERPRETED FROM SATELLITE DATA AT

LOCATION 4 (E 92°36´23.21″ N 23°28´55.71″) AND LOCATION 5 (E

92°35´46.75″ N 23°27´33.99″)



FIG 4.9: LOCATION MAP OF PROPOSED LOCATION 8 E

92°47´04.69″ N 23°18´10.04″



FIG 4.10: ETM 4 AROUND 10 KM RADIUS PROPOSED

LOCATION 8 E 92°47´04.69″ N 23°18´10.04″



FIG 4.11: LANDUSE CLASSES AROUND THE PROPOSED PROJECT

SITE AS INTERPRETED FROM SATELLITE DATA AT E

92°47´04.69″ N 23°18´10.04″



Plate 4.2 Human settlement (Built Up)

Plate 4.3 Open Forest

4.4 BIOLOGICAL ENVIRONMENT

4.4.1 Introduction

The structure and type of vegetation depends on climatic conditions and

physiography as well as the requirements of the local inhabitants of an area.

The study area is warm per-humid ecoregion with large area under tropical

semi-evergreen forests and montane sub-tropical forests. Earlier forests were

dense but due to traditional practice of jhumming cultivation from time

immemorial, large areas of forests are being converted into barren land.

However, forest department is taking steps to regenerate the forest area either

naturally and/or artificially through plantation.



4.4.2 Terrestrial Flora

The study areas are charactorized as warm per-humid eco-region with red and

laterite soils with heavy rainfall and is generally suitable for growth of all

types of forest vegetation. Table 4.14 gives the list of trees found in the study

area as obtained from the Divisional Forest Office, Aizawl.

TABLE 4.6: LIST OF FLORA IN STUDY AREA

SL. NO. ENGLISH OR COMMON NAME

MIZO NAME BOTANICAL NAME

1. Australian Wattle Kalsiamthing Acacia auriculiformis

2. -- Vawkpui-ruangruh Acacia caesia

3. Catechu or Khair Lawi-thing Acacia spp.

4. Soap pod/Shikakai Khang-thur Acacia sinuate

5. Indian Acalypha Thing-thei-hmu-par Acalypha indica

6. Putli Thing-khim Acer laevigatum

7. -- Thing-phing-phi-hlip Acer oblongum

8. -- Tu-khau Acer thomsoni

9. Chaff-flower Ui-hlo/Ui-ze-hlo Achyranthes aspera

10. -- Vang-vat-tur/Vang-vat-hlo Achyranthes bidentata

11. Mundani or Shingle Nganbawm Acrocarpus fraxinifolius

12. -- Rah-var/Par-arsi Acronychia pedunculata

13. -- Pem-hlek damdawi/Telenga-mai

Actephila excelsa

14. Red wood Senmaltet Adenanthera pavonina

15. Forest Ghost Flower Sa-nghar-vai-bel Aeginetia indica

16. Bael tree or Golden apple Bel-thei Aegle marmelos

17. Century Plant Kumza-pal/Sai-dai Agave americana

18. Goat-weed Vai(h)len-hlo Ageratum conyzoides

19. Aglaia or Amari Sa-ha-tah Aglaia pervirides

20. Gokul Phuan-berh-pui/Thing-ar-thau

Ailanthus integrifolia spp. calycina

21. Siris Vang Albizzia chinensis

22. Siris or Kokko Thing-chawk-e Albizzia lebbeck

23. Allamanda Hrui-pang-par Allamanda cathartica

24. Shallot Kawl-pu-run/Pu-run-var-sen Allium cepa var. aggregatum

25. Onion Purun-sen Allium cepa var. cepa



26. Garlic Pu-run-var Allium sativum

27. -- Arhrik-bona Allophylus zeylanicus

28. Alder or Utis Hriangpui Alnus nepalensis

29. Gaint taro Sai-dawl/Vandawl Alocasia macrorhiza

30. Java galangal Ai-chal Alpina galangal

31. Scholar or Devil tree Thuamriat Alstonia scholaris

32. Tangle Mat An-ngha-ril/Nghate-ril Alternanthera sessilis

33. Prickly Amaranth Len-hling Amaranthus spinosus

34. -- Ai-du Amomum dealbatum

35. -- The-hlei-khak Amoora chittagonga

36. Whitespot arum Ba-tel-hawng/Tel-hawngbal Amorphophallus paeonifolius

37. Cashew-nut tree Sa-zu-pum-pui-thei Anacardium occidentale

38. Pineapple La-khuih-thei Ananas comosus

39. Castard apple Thei-ar-bawm Annona squamosa

40. -- Thei-kel-ki-suak Anodendron paniculatum

41. Jewel Orchid Hnah-mawi Anoectochilus luteus

42. Kadam Banphar Anthocephalus chinensis

43. Amti Thurte-an Antidesma acidium

44. Chinese laurel Tuai-tit Antidesma bunius

45. -- Thei-she-ret Aphananthe cuspidata

46. Agarwood Thingrai Aquilaria malaccensis

47. Groundnut or Peanut Badam Arachis hypogaea

48. -- Va-hrit-thei Ardisia macrocarpa

49. -- Nau-nuar Ardisia paniculata

50. Betel-nut-palm Kuhva-kung Areca catechu

51. Malay Sago Palm Thangtung Arenga pinnata

52. -- Phel-phek Argyreia splendens

53. Indian Worm-wood or Sai Artemisia vulgaris

54. Chaplash Tat-kawng Artocarpus chama

55. Jack fruit tree Lamkhuang/La-ui Artocarpus integrifolia

56. Monkey Jack or Lakooch Thei-tat Artocarpus lakoocha

57. Gaint reed Pum-phir Arundo donax

58. Blood-flower Dingdi Asclepias curassavica

59. Spiny Asparagus or Satawar Ar-ke-bawk Asparagus racemosus

60. Wild-lime Ram-ser Atalantia monophylla



61. Carambola tree Thei-her-awt Averrhoa carambola

62. Neem or Margosa tree Nim-thing Azadirachta indica

63. Lutqua or Bhooby tree Pang-kai Baccaurea ramiflora

64. Spiny or Thorny Bamboo Vai-rua Bambusa bambos

65. Tulda Raw-lak Bambusa tulda

66. Butterfly tree Vau-fa-vang Bauhinia purpurea

67. Snake climber Zawng-a-lei-lawn Bauhinia scandens

68. Kanchan Vau-be Bauhinia variegata

69. -- Lalruanga-dar-nawhna Begonia lusshaiensis (Rare)

70. Begonia Begonia wengeri (Intermediate)

71. -- Khuang-hlang Beilschmiedia gammieana

72. -- Khuang-hlang Beilschmiedia roxburghii

73. Ash gourd or Ash Pumpkin Mai-pawl Benincasa hispida

74. Stone crusher plant Kham-dam-dawi/Pan-dam-dawi

Bergenia ciliata

75. Alder birch Hriang Betula alnoides

76. Darjeeling birch Hriang-zau Betula cylindrostachys

77. Bishop wood or Uriam Khuang-thli Bischofia javanica

78. Silk cotton tree or Semul Phun-chawng Bombax malabaricum

79. Didu Pang Bombax insigne

80. Palmyra or Toddy Palm Sial-lu Borassus flabellifer

81. Bougainvillea Sa-rawn Bougainvillea spectabilis

82. Mustard An-tam Brassica juncea

83. Cauliflower Par-bawr Brassica oleracea var. botrytis

84. Cabbage Zik-hlum Brassica oleracea var. capitata

85. Knol-kohl or Kohlrabi Bul-bawk Brassica oleracea var. gongylodes

86. Broccoli Brokoli Brassica oleracea var. italica

87. Mustard or Chinese Cabbage An tam Brassica rapa

88. Kasi Thing-phak-tel Bridelia squamosa

89. Trumpet flower Tawtawrawt par Brugmansia suaveolens

90. -- Thual-thu Butea buteiformis

91. -- Za-thoh/Ngawi-hrui Butea parviflora

92. -- Hling-khang Caesalpinia spp.

93. Lentil or Pigeon pea Be-hliang Cajanus cajan

94. Gouri bet Mit-perh Calamus acanthospathus



95. -- Mawt Calamus andamanicus

96. Kadam bet Hrui-pui Calamus erectus

97. Sundi bet Tai-te/Tai-rua Calamus guruba

98. Jali or Jalla bet Thil-te Calamus tenuis

99. -- Hnah-kiah Callicarpa arborea

100. Bottle-brush tree Botol-bras Callistemon citrinus

101. Madar or Crown plant Hnah-pawl Calotropis gigantea

102. Kissi Lal-lai Camellia kissi

103. Tea-plant Thing-pui Camellia sinensis

104. Chilli or Red pepper Hmar-cha Capsicum annum

105. Sweet pepper Hmarchapui Capsicum frutescens

106. Carallia or Maniawga Thei-ria Carallia brachiata

107. Payaya or Papaw-tree Thing-fang-hma/Nu-hnun Carica papaya

108. -- Lalruang-beh-thi Caryopteris paniculata

109. Palm tree Mei-hle Caryota mitis

110. Fishtail-palm Tum Caryota urens

111. Ringworm shrub Da-du-hlo/Kel-be-bui/ Cassia alata

112. Indian Laburnum or Amaltas Ngai-ngaw/Phung-ril Cassia fistula

113. Pink and White shower Mak-pa-zang-kang Cassia nodosa

114. Coffee senna Reng-an Cassia occidentalis

115. -- Mitthi-zawng-tah/Se-be-hliang

Cassia timoriensis

116. Cassia floribunda

117. Foetid cassia Kel-be Cassia tora

118. -- Then-ngo/Then-mm Castanopsis echinocarpa

119. -- Rem-te Cayratia mollis

120. -- Puar-peng Cayratia obovata

121. White cotton tree or Kapok Japan-pang Ceiba pentandra

122. Cock’s comb Zo-ar-chhuang Celosia argentea fa. cristata

123. Nettle tree or Caltis An-ku/Vai-bawng-chaw Celtis australis

124. Pennywort Lam-bak/Dar-beng-bur Centella asiatica

125. Plum-yew Tu-far/Leh-ngo-far Cephalotaxus griffithii

126. Labshi Thei-khuang-chawm Choerospondias axillaris

127. Common Floss Flower Tlang-sam/Pho-leng Chromolaena odorata

128. Chrysanthemum October-par Chrysanthemum indicum

129. Bay leaf or Tejpat Tespata/Hnah-rimtui Cinnamomum tamala



130. True cinnamon or Dalchini Thak-thing Cinnamomum verum

131. -- Len-hling/Zo-len-hling Cirsium chinense

132. Water melon Dawn-fawh Citrullus lanatus

133. Acid lime Ser-tui-bur/Ser-sawr Citrus acida

134. Sour lime or Kagzinebu Serte/Champara Citrus aurantifolia

135. Pumelo or Shaddock Ser-tawk/Sai-ser/Sa-hawk Citrus grandis

136. Wild Orange Ser Citrus indica

137. Lemon or Bara Nimbu Ser (Ser-fang) Citrus limon

138. Acid or Sour Lime or Nimbu Limbu Citrus medica var. acida

139. Orange or Kamala Serthlum Citrus reticulata

140. -- Phui-hnam Clerodendrum colebrookianum

141. Bharangi Lei-dum-suak Clerodendrum serratum

142. -- Lei-dum Clerodendrum venosum

143. Hill clerodendrum Phui-hnam-chhia Clerodendrum viscosum

144. -- -- Clerodendrum wallichii

145. Coconut palm Na-rial-thing Cocos nucifera

146. Orchid Coelogyne rossiana (Vulnerable)

147. Coffee Coffee-thing Coffea arabica

148. -- Chep-ngul Coffea khasiana

149. Taro Bal/Dawl Colocasia esculenta

150. Sebestens Muk-fang Cordia dichotoma

151. Kew Sum-bul Costus speciosus

152. Sunn hemp Tum-thang Crotalaria juncea

153. -- Ba-pui-ken-hnah-hlai Croton roxburghii

154. Japanese cedar or Suji Japan-far Cryptomeria japonica

155. Sweet or Honey-dew melon Hma-zil Cucumis melo var. saccharinus

156. Cucumber Fang-hma Cucumis sativus

157. Pumpkin or Winter squash Mai/Mai-an Cucurbita maxima

158. Black zedoary or Kalahaldi Ai-lai-dum Curcuma caesia

159. Turmeric plant or Haldi Ai-eng Curcuma longa

160. -- Ai-thur Curcumorpha longiflora

161. Dodder plant Bawirai ral Cuscuta reflexa

162. Java citronella Di-rim-tui/Di-leng-ser Cymbopogon winterianus

163. Dog grass or Dub-grass Phai-tual-hlo Cynodon dactylon

164. Tree tomato Thing-tomato/Thing-be-ra Cyphomandra betacea



165. Gola bet Raichhawk Daemonorops jenkinsianus

166. Burma rosewood Khum Dalbergia oliveri

167. Carrot Carrot Daucus carota

168. Gulmohur April-par Delonix regia

169. Orchid Dang-hang/Lik-dum-dial Dendrobium spp.

170. Giant Bamboo Vai-mau Dendrocalamus giganteus

171. Rhino bamboo Phul-rua Dendrocalamus hamiltonii

172. Male Bamboo An-kuang & Tur-sing Dendrocalamus strictus

173. Devil or fever nettle Thak-pui Dendrocnide sinuata

174. Telegraph Plant Tuan-i-them-tang Desmodium motorium

175. Elephant apple Kawr-thin-deng Dillenia indica

176. White or Winged Yam Ba-chhim & Rambachhim Dioscorea alata

177. Chinese Yam Hra-kai Dioscorea belophylla

178. Bulb bearing yam Vawkpui-ba-hra Dioscorea bulbifera

179. Ebony Thei-kum Diospyros spp.

180. Wood oil tree or Gurjan Lawng-thing Dipterocarpus indicus

181. Hollong Thing-sen Dipterocarpus retusus

182. Indian Crab Apple Sun-hlu-pui Docynia indica

183. Lampati Zuang Duabanga grandiflora

184. -- Vai-thei-hmu/Lei-thei-hmu Duchesnea indica

185. Sky flower Hling-dai/Kawl-dai-hling Duranta repens

186. Devdam Sa-ha-tah Dysoxylum binectariferum

187. Cardamom or Elaichi Alaichi Elettaria cardamomum

188. Amla Sun-hlu Emblica officinalis

189. Gaint’s Rattle Kawi-hrui Entada scandens

190. -- Nghal-chhun Eriobotrya bengalensis

191. -- Kal Eriolaena spectabilis

192. Wild Coriander Bah-khawr/Ba-chi-khawm Eryngium foetidum

193. Coral Tree Far-tuah Erythrina variegata

194. Lemon-scented gum Naw-alh-thing Eucalyptus citriodora

195. Blue gum Naw-alh-thing Eucalyptus globulus

196. Lal dhudi or Common

spurge

Hnute-tui-tam-na Euphorbia hirta

197. Poinsettia Mas-par/Hnah-sen Euphorbia pulcherrima

198. Banyan tree Bung Ficus benghalensis



199. Java fig Za-man-hmawng Ficus benjamina

200. Indian rubber Thel-ret/Thial-ret Ficus elastica

201. Cluster fig Thei-chek & Chho-he Ficus racemosa

202. Pipal Hmawng Ficus religiosa

203. Gamboge tree Kawr-vawm-va Garcinia morella

204. Soyabean Be-kang Glycine max

205. Gmelina or Gamari Thlan-vawng Gmelina arborea

206. -- Pelh Gnetum gnemon

207. -- Thal-ping Gnetum montanum

208. Tree cotton La Gossypium arboreum

209. Silver Oak Silver Oak Grevillea robusta

210. Chaulmurga Sai-thei Gynocardia odorata

211. Haldu Lung-khup Haldina cordifolia

212. Butterfly Lily Ai-nawn Hedychium coronarium

213. Spiked Ginger Lily Ai-thur Hedychium spicatum

214. -- Kel-hnam-tur Hedyotis scandens

215. Sunflower Ni-hawi Helianthus annuus

216. Bird of Paradise Chang-el-par Heliconia angustiflolia

217. China Rose Hibiscus spp.

218. Chalmoogra Hydnocarpus kurzii

219. Chameli Jasminum scandens

220. Flame of forest Lagerstroemia flosreginae

221. Champa Magnolia spp.

222. Mango Mangifera indica

223. Jungli neem Neem thing Melia azedarach

224. Sairil Melocalamus compactiflorus

225. Ironwood Mesua ferrea

226. Champa Michelia champaka

227. Mulberry Morus indica

228. -- Saisu Musa superba

229. Mussaenda Mussaenda spp.

230. Patabahar Paederia foetida

231. Orchid Paphiopedilum hirsutissimum (Rare)

232. Orchid Paphiopedilum villosom (Vulnerable)



233. Amla Phyllanthus spp.

234. Pepper Piper bettleiodes

235. Orchid Renanthera imschootiana (Endangered)

236. Sal Shorea robusta

237. Amra Spondiais pinnata

238. Hogplum tree Taitaw Sondia pinnata

239. Teak Tectona grandis

240. Vanda orchid Vanda coerulea

241. Lalruanga Dawi bur Zanonia spp.

242. Ginger Zingiber officinale

4.4.3 TERRESTRIAL FAUNA

Since the study area has extensive forests, the area can support fairly large

variety of wild life. Table 4.6 gives the list of wild animals and birds

commonly found in the forests of the study area as obtained from the

Divisional Forest Office, Aizawl.

TABLE 4.6 FAUNA IN STUDY AREA

SL. NO. COMMON NAME MIZO NAME SCIENTIFIC NAME

ANIMALS

1. Clawless Otter Sa-hram (Hram-te) Aonix cinerea

2. Binturong or Bear-cat Zam-phu Arctictis binturong

3. Hog-badger Phi-vawk Arctoryx collaris

4. Indian Mole-rat Sa-zu (Zu-pawl) Bandicota bengalensis

5. Large Bandicoot Rat Tam-pui Bandicota indica

6. Bison or Gaur Ram-sial Bos gaurus

7. Red-bellied Palla’s Squirrel

Hlei-kap-sen Callosciurus erythraeus

8. Himalayan Striped Squirrel

Hlei-mual-rang/Hlei-te Callosciurus macclellandi

9. Himalayan Hoary bellied Squirrel

Hlei-zawng Callosciurus pygerythrus

10. Jackal Si-hal Canis aureus



11. Bay Bamboo Rat or Lesser Bamboo Rat

Bui-sen Cannomys badius

12. Sero Sa-za Capricornis sumatraensis

13. Sambar Sa-zuk Cervus unicolor

14. Dhole or Wild Dog Ching-hnia Cuon alpinus

15. Orange-bellied Himalayan Squirrel

Hlei-lu-bial Dremomys lokriah

16. Leopard Cat Sa-nghar Felis bengalensis (SCARCE)

17. Jungle Cat Nghar-bawr/sa-uak Felis chaus

18. Golden Cat Kei-sen Felis temmincki

19. Fishing Cat Nghar-buang Felis viverrina

20. Small Indian Mongoose -- Herpestes auropunctatus (SCARCE)

21. Crab-eating Mongoose Sa-phai-ruang Herpestes urva

22. Hoolock Gibbon Hau-huk Hylobates hoolock

23. Particoloured Flying Squirrel

Biang Hylopetes alboniger

24. Crestless Himalayan Porcdupine or Chinese Porcupine

Sa-kuh Hystrix brachyuran

25. Common Otter Sa-hram (Hram-pui) Lutra lutra

26. Stump-tailed Macaque Zawng-mawt Macaca arctoides

27. Assamese Macaque Zozawng/Khamzawng Macaca assamensis

28. Rhesus Macaque Phai-zawng Macaca mulatta

29. Pig-tailed Macaque Zawng-hmel-tha/ Zawng-bak-buk

Macaca nemestrina

30. Chinese Pangolin Saphu Manis pentadactyla

31. Yellow-throated Marten Sa-fia/Sa-fe-tum-bung-rang

Martes flavigula

32. Chinese Ferret-badger Sa-hmai-tha Melogale moschato

33. Barking Deer or Muntjak

Sa-khi Muntiacus muntjak

34. Yellow-bellied Weasel Sa-ri-vai-thun Mustela kathiah

35. Stripedbacked Weasel Sa-ri-vai-thun Mustela strigidorsa

36. Goral Sa-thar Nemorhaedus goral

37. Clouded Leopard Kel-ral/Zawng-ral Neofelis nebulosa



38. Slow Loris Sa-huai Nycticebus coucang (SCARCE)

39. Himalayan Palm Civet Sa-zaw (Zaw-buang) Paguma larvata

40. Leopard or Panther Kei-te Panthera pardus (SCARCE)

41. Toddy Cat or Common Palm Civet

Sa-zaw (Zaw-hang) Paradoxurus hermaphroditus

42. Common Giant Flying Squirrel Red Flying Squirrel

Va-hluk Petaurista petaurista

43. Silvered Leaf Monkey Ngau Presbytis geei

44. Golden Langur Ngau-sen/Ngau-ir-eng Presbytis phayrei

45. Capped Langur Ngau-buang Presbytis pileatus (SCARCE)

46. Spotted Linsang or

Tiger-civet

Nghar-thing-awn Prionodon pardicolor

47. Indian Flying Fox Bak-sai Pteropus giganteus

48. White-tailed Wood Rat Zu-thel Rattus blanfordi

49. House Rat or Black Rat Sa-zu Rattus rattus

50. Malayan Giant Squirrel Awr-rang Ratufa bicolor

51. Red-cheeked Bamboo Rat

Bui-pui Rhizomys erythrogenys

52. Hoary Bamboo Rat Bui-luang-par Rhizomys pruinosus

53. Grey Musk Shrew Chhim-tir Suncus murinus

54. Wild Boar or Wild Pig Sa-nghal Sus scrofa

55. Short-tailed Mole Bui-ke-lek Talpa micrura

56. Northern Tree-shrew Che-pa Tupaia belangeri

57. Malayan Sun Bear Mang-tir/Sa-mang Ursus malayanus

58. Himalayan Black Bear Vawm-sai/Vawmkhang Ursus thibetanus

59. Sloth Bear Sa-vawm-bak-buk Ursus ursinus

60. Longtailed Tree Mouse Chim-buang Vandeleuria oleracea

61. Large Indian Civet Tlum-pui Viverra zibetha (SCARCE)

62. Small Indian Civet Tlum-therh Viverricula indica (SCARCE)

BIRDS

63. Warbler Va-te Abroscopus spp.

64. Shikra Mu-te Accipiter badius



65. Besra Mu-te Accipiter virgatus

66. Rufous-necked Hornbill Va-awk Acerois nipalensis (ENDANGERED)

67. Common Myna In-vai-va/Phai-vai-va Acridotheres tristis

68. Rusty-fronted Barwing Zo-va-lu-buk Actinodura egertoni

69. Redheaded Tit Ram-chawngzawng Aegithalos concinnus

70. Common Iora Zai-rum-va Aegithina tiphia

71. Common or Small Blue Kingfisher

Kai-kuang-ral-te-chi Alcedo atthis

72. Rufous-winged Fulvetta Vate chi khat Alcippe castaneceps

73. White-breasted Waterhen Tui-ar Amaurornis phoenicurus

74. Golden-crested Myna Vai-va-bawi Ampeliceps coronatus

75. Common Pintail Tui-va-rak Anas acuta

76. Oriental Darter Va-ching-ring-

diau/Vara

Anhinga melanogaster

77. Indian Pied Hornbill Va-hai Anthracoceros albirostris (ENDANGERED)

78. Ruby-cheeked Sunbird Va-te Anthreptes singalensis

79. Streaked Spiderhunter Ki-reuh Arachnothera magna

80. Darkbacked Swift Kham-va-mur Apus acuticauda

81. House Swift Va-mur-ngum-var Apus affinis

82. White-cheeked Partridge Va-rung Arborophila spp.

83. Heron Ngawi-hup/Kawl-pui-sa-ruh-hak

Ardea spp.

84. Ashy Swallow-shrike Leng-der/Mur-pawl/Len-thiam

Artamus fuscus

85. Jerdon’s Baza Mu-chi-khat Aviceda jerdoni

86. Black Baza Mu-kel-rang Aviceda leuphotes

87. Chinese Babax Zova lei-sawt/Ngal-va-pual-nu

Babax ianceolatus

88. Assam Bamboo Partridge Va-hlah Bambusicola fytchii hopkinsoni

89. Hodgson’s Frogmouth Va-bak-chi-khat Batrachostomus hodgsoni

90. Bay Woodpecker Fang-hmir-thloh Blythipicus pyrrhotis

91. Lesser Shortwing Hmun-chhe-ar-pui Brachypteryx leucophrys

92. Forest or Spot-bellied Chhim-buk-pui Bubo nipalensis



Eagle-owl (ENDANGERED)

93. Brown Fish Owl Tui-tu Bubo zeylonensis

94. Great Hornbill Va-pual Buceros bicornis (ENDANGERED)

95. Common Buzzard Mu Buteo buteo

96. Plaintive Cuckoo Mawntaipirtliak Cacomantis merulinus

97. Nightjar Va-lam-bawk/Va-bak Caprimulgus spp.

98. Yellow-breasted Green-finch

Tep Cardeulis spinoides

99. Common Rosefinch Va-suih Carpodacus erythrinus

100. Lesser Coucal Va-dar-khuang/Lalruang-se-hnawt-te-chi

Centropus bengalensis

101. Greater Coucal Lalruanga-se-hnawt Centropus sinensis

102. Brown-throated Tree-creeper

Va-lim-chho Certhia discolor

103. Crested Kingfisher Kai-kuang-ral Ceryle lugubris (ENDANGERED)

104. Leafbird Chhawl-hring Chloropsis spp.

105. Violet Cuckoo -- Chrysococcyx xanthorhynchus

106. Large Goldenbacked Woodpecker

Thloh-pui Chrysocolaptes lucidus

107. Whitetailed Blue Robin Ka-pi-tui-bur-kei-ve Cinclidium leucurum

108. Green Magpie Dawn-tliang Cissa chinensis

109. Redwinged Crested Cuckoo

-- Clamator coromandus

110. Green Cochoa Zo-va-chan Cochoa viridis

111. Himalayan Swiftlet Ram-va-mur Collocalia brevirostris

112. Speckled Wood Pigeon Zo-bul-lut/Bul-lut-tial Columba hodgsonii

113. Magpie Robin Chang-er/Khawmual-chinrang

Copsychus saularis

114. Indian Roller Va-pui Coracia benghalensis

115. Jungle Crow Cho-ak Corvus macrorhynchos

116. White-throated Bulbul Daw-kek Criniger flaveolus

117. Common Cuckoo Riak-maw Cuculus canorus

118. Nepal Cutia -- Cutia nipalensis



119. Palm Swift In-va-mur Cypsiurus parvus infumatus

120. Common-House-Martin Fuanhawr Delichon urbica

121. Grey Tree-Pie Bem-kawng Dendrocitta formosae

122. Flower pecker Va-te-awm-tial/Tek-tek-awm-tial

Dicaem spp.

123. Drongo Kul-herh Dicrurus hottentottus

124. Green Imperial Pigeon Phai-bul-lut Ducula aenea (ENDANGERED)

125. Imperial Pigeon Bul-lut Ducula badia (ENDANGERED)

126. Little Bunting Chip-te Emberiza pusilla

127. Forktail Chin-rang Enicurus spp.

128. Siberian Rubythroat Tawk-tawk-awr-sen Erithacus calliope

129. Great Eared Nightjar Va-lam-bawk/Va-bak Eurostopodus macrotis

130. Broad-billed Roller Va-kek/Va-pui-hmui-sen

Eurystomus orientalis

131. Falcon Mu-ngek Falco peregrines

132. Flycatcher Va-dum-de-leng-chi-khat

Ficedula spp.

133. Common Moorhen Dil-ar/Tui-va-rung Gallinula chloropus

134. Snipe Chirh-dawt Gallinago gallinago

135. Red Junglefowl Ram-ar Gallus gallus

136. White-headed Shrike-babbler

Phai-ko-ro Gampsorhynchus rufulus

137. East Himalayan Redcrowned Jay

Va-far Garrulus glandarius

interstinctus

138. Pale-headed Woodpecker Fang-hmir-thloh Gecinulus grantia

139. Owlet Hrang-kir/Phawng-phaw-dawt

Glaucidium brodiei

140. Barred Owlet Chhim-buk-te (Vawk-chhuk)

Glaucidium cuculoides

141. Tiger Bittern -- Gorsachius melanolophus

142. Hill Myna Vai-va/Ram-vai-va Gracula religiosa

143. White-rumped Vulture Mu-lu-kawlh Gyps bengalensis

144. Scarlet Finch Suipui/Va-suiphi Haematospiza sipahi

145. Bar-winged Flycatcher-shrike

-- Hemipus picatus



146. Sibia Sir-bial/Sir-lu-bial/Sir-bawl

Heterophasia spp.

147. Eagle Mu-ar-la Hieraaetus kienerii

148. Needletail Mur-pui Hirundapus spp.

149. Red-rumped Swallow Va-mur-ngum-sen Hirundo daurica

150. Black-naped Flycatcher Va pawl Hypothymis azurea

151. Bulbul Va-rit/Lian-do-rit/Hmui-sen/ Vachiap

Hypsipetes spp.

152. Black Eagle Lung-dup Ictinaetus malayensis

153. Yellow-rumped Honeyguide

Tep-Va-te-ngum-eng Indicator xanthonotus

154. Fairly Bluebird Va-dar-tle Irena peulla

155. Black Headed Shrike Chhem-hur Lanius schach tricolor

156. Assam Silver-eared Mesia

Thlangvaharbeh/Dawk-

vel

Leiothrix argentauris

aureigularis

157. Munia Pit-sen/Pit-lu-dum Lonchura spp.

158. Yellow-breasted Babbler Va-te-chi-khat Macronous gularis

159. Blue throated Barbet Tuk-lo Megalaima asiatica

160. Sultan Tit Va-kel-chal Melanochlora sultanea

161. Crested Bunting Phai-tep Melophus lathami

162. Chestnutheaded Bee-eater

Tlak-awrh-lu-sen Merops spp.

163. Rufous Woodpecker Thloh-kawr-ha Micropternus brachyurus

164. Bluewinged Siva Chang-rual/Dar-hnawk/Saivate

Milna cyanouroptera

165. Blackeared or Large Indian Kite

Mu-chhia Milvus migrans

166. White Wagtail Lailen Motacilla spp.

167. Great Slaty Woodpecker Thloh-sai Mulleripicus pulverulentus

168. Large Niltava Va-pawl/Va-dum-de-leng

Niltava grandis

169. Night Heron Tui-sa-va-var-zang-hang

Nycticorax nycticorax

170. Slender-billed Oriole Va-mai-tai/Bawngpui Oriolus tenuirostris

171. Blacknecked Tailor-bird Hnah-khawr/Hnah-fun/Che-de-de

Orthotomus atrogularis

172. Owl Chhim-buk Otus spilocephalus



173. Grey-headed Parrotbill Va-hnang-hlai Paradoxornis gularis

174. Burmese Black-spotted Yellow Tit

Zo-va-kel-chal Parus spilonotus subviridis

175. House Sparrow Chawngzawng Passer domesticus

176. Minivet Bawng Pericrocotus spp.

177. Green-billed Malkoha Va-zun/Va-uk Phaenicophaeus tristis

178. Bay-owl Tah-ngai-beng-nei Phodilus badius

179. Woodpecker Thloh-kawr-ha Picoides atratus

180. Speckled Piculet Thloh-kawr-ha Picumnus innominatus malayorum

181. Woodpecker Thloh-lu-par Picus spp.

182. Hume’s Pheasant Va-ri-haw Polyplectron bicalcaratum bakeri (ENDANGERED)

183. Mizo Coral-billed

Scimitar-babbler

Ngal-va-pual Pomatorhinus ferruginosus phayrei

184. Purple Moorhen Dum-sava Porphyrio porphyrio poliocephalus

185. Assam Blackthroated Hill Warbler

Zir-ziak Prinia atroigularis khasiana

186. Assam Brown Hill Warbler

Chang-dawt Prinia criniger catharia

187. Longtailed Broadbill Thi-zil Psarisomus dalhousiae

188. Alexandrine Parakeet Va-ki Psittacula spp.

189. White Throated Brown Hornbill

Va-khaw-pui/Va-ngai Ptiloaemus tickelli

190. Bulbul Tlai-berh/Se-tawt Pycnonotus spp.

191. Wreathed Hornbill Kawl-hawk Rhyticeros undulates

192. Longbilled Wren-babbler Hmun-chhe-ar-pui Rikmator malacoptilus

193. Rufous Piculet Luang-tu-bek/Mau-thloh

Sasia ochracea reichenowi

194. Woodcock Chirh-dawt-lian-chi Scolopax rusticola

195. Silver-breasted Broadbill Thi-zil-chi-khat Serilophus lunatus

196. Eastern Chestnut-bellied Nuthatch

Suk-let Sitta castanea cinnamoventris

197. Chin Hills Long tailed Wren-babbler

Valeisawt Spelaeornis chocolatinus

oatesi

198. Crested Serpent Eagle Mu-van-lai Spilornis cheela



(ENDANGERED) 199. Golden Babbler Va-te-chi-khat Stachyris chrysaea

200. Burmese Spotted Dove Thu-ro-nghawng-tial/Chuk-chu-ru-kuri-nu

Streptopelia chinensis tigrina

201. Rufous Turtle Dove Mim-siri-kut Streptopelia orientalis agricola

202. Himalayan Wood Owl Ching-pi-ri-nu-chi-khat Strix aluco nivicola

203. Myna Vai-va Sturnus spp.

204. Drongo Cuckoo Tui-mal-far-fep-fep Surniculus lugubris

205. Bhutan Peacock Pheasant Va-vu Syrmaticus humiae humiae (ENDANGERED)

206. Large Wood-shrike Thlek-bur Tephrodornis virgatus

207. East Himalayan Paradise Flycatcher

Thleh-hniar Terpsiphone paradise saturatior

208. Tesia Va-te-mei tawi Tesia castaneocoronata

209. River Chat Va-tui-heng khum/ Va-chal-de

Thamnolaea leucocephala

210. Red-capped Babbler Tek-tek Timalia pileata

211. Blyth’s or Greybellied Tragopan

Va-nga/Va-ngai/Vung-ar

Tragopan blythii (ENDANGERED)

212. Wedge-tailed Pigeon Va-hui-(Hui-pui-thla-ki-sen)

Treron sphenura

213. Grey-winged Blackbird Va-dar-tle/ Chip-pui-thla-rang

Turdus boulboul

214. Burmese Yellowlegged Buttonquail

Va-hmim Turnix tanki blanfordii

215. Barn Owl Tah-ngai Tyto alba stertens

216. Assam Slender-billed Scimitar-babbler

Ngalvapual Xiphirhynchus superciliaris

217. Smallbilled Mountain Thrush

Ar-chham Zoothera dauma

4.4.4 AGRICULTURAL CROPS IN THE STUDY AREA

Jhumming and shifting cultivation is the principal method of cultivation and

about 80% of the rural population is engaged in cultivation. Paddy, maize,

wheat, oil seeds, pulses, peas, groundnut and some cash crops like cotton,

sugarcane, potato and pioca and vegetables are grown to some extent in the

study area.



4.5 DEMOGRAPHIC ENVIRONMENT

4.5.1 Introduction

Baseline environmental scenario in the study area with respect to demographic

and socio-economic conditions has been discussed in the subsequent sections

of this chapter.

Data on number of villages, number of households, population, schedule

castes and scheduled tribe population and literacy rate in each village in the

block/study area has been obtained from Soft Copy (CD) of Primary Census of

Mamit, Aizawl, Serchhip and Lunglei Districts (2001). Demographic details of

105 villages and 2 notified towns, namely, Serchhip and Thenzawl falling in

the study area are given in Table 4.7 (a) & (b)

4.5.2 Population

Table 4.7 (a) & (b)

gives the data on village/town name, number of households and population

distribution by sex as per 2001 census records for all villages/towns in the

study area.

The study area sustains a total population of 95,698 as per 2001 census

records. Urban population in 2 notified towns is 22,603 (23.62%) and rural

population in 105 villages is 73,095 (76.38%). The male population

constitutes nearly 51.08% while female population is 48.92% of the total

population in the study area.

TABLE 4.7 (a) : POPULATION OF THE STUDY AREA

Sl. No. District TRU Persons Males Females ST

Population SC

Population 1. Aizawl Total 325,676 166,877 158,799 303,641 182

2. Aizawl Rural 77,531 40,333 37,198 75,024 28

3. Aizawl Urban 248,145 126,544 121,601 228,617 154

4. Lunglei Total 137,223 71,402 65,821 130,768 33

5. Lunglei Rural 79,267 41,283 37,984 76,971 5

6. Lunglei Urban 57,956 30,119 27,837 53,797 28



7. Mamit Total 62,785 33,114 29,671 58,950 18

8. Mamit Rural 52,132 27,603 24,529 49,465 16

9. Mamit Urban 10,653 5,511 5,142 9,485 2

10. Serchhip Total 53,861 27,380 26,481 52,830 5

11. Serchhip Rural 27,983 14,369 13,614 27,398 5

12. Serchhip Urban 25,878 13,011 12,867 25,432 0

TABLE 4.7 (b) : NUMBER OF HOUSEHOLDS AND AVERAGE HOUSEHOLD SIZE OF THE STUDY AREA

Sl. No. District TRU No. of households Average household size

1. Aizawl Total 64,395 5.0

2. Aizawl Rural 15,546 5.0

3. Aizawl Urban 48,849 5.0

4. Lunglei Total 27,832 4.9

5. Lunglei Rural 15,516 5.1

6. Lunglei Urban 12,316 4.6

7. Mamit Total 12,201 5.1

8. Mamit Rural 10,060 5.1

9. Mamit Urban 2,141 5.0

10. Serchhip Total 10,102 5.3

11. Serchhip Rural 5,205 5.4

12. Serchhip Urban 4,897 5.3

4.5.3 Population Density

Since village land area data is not available, population density in inhabited

villages cannot be determined. However, on the basis of total block area of

3213 sq. km, the population density is found to be only 29.8 persons/sq. km.

4.5.4 Sex Ratio

As per 2001 census records, sex ratio defined as the number of females per



1000 males for the study area is nearly 958.

4.5.5 Scheduled Castes/Tribes

As per 2001 census records, scheduled castes population is merely 0.03%

(0.06% males and 0.00% females) while scheduled tribes population is

98.43% (97.63% males and 99.25% females).

4.5.6 Literacy

As per 2001 census records, 79.29% population of the study area of is literate,

80.44% males and 78.09% females.

TABLE 4.8 : EDUCATIONAL LEVEL AND WORK STATUS OF MIZORAM

SL.

NO. TRU EDUCATIONAL LEVEL PERSONS MALES FEMALES

1 Total Total 362,450 225,428 137,022

2 Rural Total 201,599 120,662 80,937

3 Urban Total 160,851 104,766 56,085

4 Total Illiterate 39,474 20,609 18,865

5 Rural Illiterate 33,783 16,782 17,001

6 Urban Illiterate 5,691 3,827 1,864

7 Total Literate 322,976 204,819 118,157

8 Rural Literate 167,816 103,880 63,936

9 Urban Literate 155,160 100,939 54,221

10 Total Literate but below matric/secondary 251,695 155,864 95,831

11 Rural Literate but below matric/secondary 143,427 86,210 57,217

12 Urban Literate but below matric/secondary 108,268 69,654 38,614

13 Total Matric/secondary but below graduate 42,932 29,372 13,560

14 Rural Matric/secondary but below graduate 14,123 10,512 3,611

15 Urban Matric/secondary but below graduate 28,809 18,860 9,949

16 Total Technical diploma or certificate not equal to degree

834 682 152



17 Rural Technical diploma or certificate not equal to degree

180 166 14

18 Urban Technical diploma or certificate not equal to degree

654 516 138

19 Total Graduate and above other than technical degree

15,802 11,091 4,711

20 Rural Graduate and above other than technical degree

3,143 2,575 568

21 Urban Graduate and above other than technical degree

12,659 8,516 4,143

22 Total Technical degree or diploma equal to degree or post-graduate degree

3,212 2,549 663

23 Rural Technical degree or diploma equal to degree or post-graduate degree

834 751 83

24 Urban Technical degree or diploma equal to degree or post-graduate degree

2,378 1,798 580

4.6 SOCIO-ECONOMIC ENVIRONMENT

4.6.1 Introduction

Data on employment pattern and infrastructure facilities in each of the

villages/towns of the study area has been obtained from of Census of Mamit,

Aizawl, Serchhip and Lunglei districts (2001).

4.6.2 Employment Pattern

The employment pattern in the study area is an indicator of number of persons

employed in various sectors. It also indicates the various categories of

employment flourishing in the area. The employment pattern in the study area

is presented in Table 4.9 as per Census 2001.

TABLE: 4.9 EMPLOYMENT PATTERN

EMPLOYMENT PATTERN DISTRICT PERSONS MALES FEMALES

TOTAL WORKERRS

Aizawl 162,961 94,481 68,480 Lunglei 71,792 40,907 30,885 Mamit 35,165 19,404 15,761 Serchhip 32,523 17,104 15,419



TOTAL MAIN WORKERS


TOTAL MARGINAL WORKERS


TOTAL NON - WORKERS


WORK PARTICIPATION

RATE

Aizawl 50.0 56.6 43.1 Lunglei 52.3 57.3 46.9 Mamit 56.0 58.6 53.1 Serchhip 60.4 62.5 58.2

NO. OF CULTIVATORS


NO. OF AGRICULTURAL

LABOURERS

Aizawl 6,751 3,260 3,491 Lunglei 2,781 1,307 1,474 Mamit 2,229 1,075 1,154 Serchhip 1,420 725 695

HOUSEHOLD INDUSTRY WORKER

Aizawl 3,029 1,460 1,569 Lunglei 597 325 272 Mamit 315 204 111 Serchhip 893 357 536

NO. OF OTHER WORKERS


In the study area, total main workers account for 47.06% (53.00% male and

40.86% female) and whereas marginal workers and non-workers respectively

account for 14.12% (10.30% males and 18.11% females) and 38.82% (36.70%

males and 41.03% females).



In the study area, out of main workers, cultivators account for 78.74%

(74.65% males and 84.27% females) followed by agricultural labourers at

1.94% (1.97% males and 1.90% females), household industry workers at

1.70% (1.48% males and 2.00% females) and the rest 17.62% are other

workers (21.90% males and 11.83% females). It is, therefore, clear that most

of the main workers are engaged in agricultural activities as cultivators.

In may be noted that the definition of non-workers in census records includes

person engaged in household duties or an infant, or is a student, or a

dependent, or a retired person, or a beggar, or engaged in other non-productive

economic activity.

4.6.3.1 Educational Facilities

As per 2001 Census, out of 105 inhabited villages, 101 villages have one or

more primary schools, 88 villages have one or more middle schools, 47

villages have one or more secondary schools and 1 village has senior

secondary schools. Only 4 villages do not have any educational facility and

can have access to primary school at a distance of 5 to 10 /10+ km.

4.6.3.2 Medical Facilities

As per 2001 census records, only 3 villages have health centres, 14 villages

have primary health centres and 49 villages have primary health sub-centres.

Other villages in the study area can have access to these facilities at a distance

of 5 to 10 /+ 10 km.

4.6.5 INDUSTRIAL AND COMMERCIAL ACTIVITIES

The study area does not have any important industrial or commercial activity.

EIA for Exploratory Drilling & Testing in Block MZ-ONN-2004/1(Mizoram) 5-1


CHAPTER 5: ENVIRONMENTAL IMPACT ASSESSMENT

5.1 INTRODUCTION

For proper assessment of impact it becomes essential to understand various

activities which may result in environmental pollution during drilling and

testing at the promising locations for hydrocarbons availability of the block

area.

It may be noted that drilling and testing of the exploratory wells are proposed

to be carried out within the block area having forested hilly terrain along with

valleys of many rivers and some thinly populated villages/towns close to

major roads in the block area. Locations of proposed wells are not finalized so

far and, therefore, the entire area of the block has been covered in this study.

Normal operational pollution sources during drilling and testing are: drilling

discharges, drainage discharges, gaseous emissions due to operation of DG

sets and movement of vehicles, domestic wastewater, noise and heat

generation as well as formation water and gaseous emissions from flare

generated during assessment testing for oil and gas. The use of relatively eco-

friendly water based mud (WBM) as a drilling fluid and adoption of

appropriate strategy for abatement and control of pollution by OIL are

expected to minimize the impact of drilling and exploratory testing operations

on the surrounding environment of drilling sites. An objective assessment is

made in the following sections both for adverse and beneficial impacts on

various environmental parameters in the study area due to drilling and testing

operations.

5.2 TOPOGRAPHY AND PHYSIOGRAPHY

There will be no impact of drilling at the exploratory locations and assessment

testing for oil and gas on topography and physiography of the study area.

5.3 SOILS

Mast cellar of the rig will occupy nearly 5 m x 5 m area and overall

operational area at one exploratory drilling site will be nearly 110 m x 150 m

(1.65 ha). Therefore, alluvium derived soils of only 1.65 hectare are likely to



be affected around each of the exploratory drilling locations due to site

preparation for drilling and assessment testing activities.

Drilling discharges, drainage discharges and wasted WBM will be collected in

shallow pits to be located close to the exploratory drilling locations. These

shallow effluent pits will have HDPE lining to prevent seepage of effluents

into ground aquifers. Clarified water at the top of effluent pits will partly

evaporate especially in non-rainy period and remaining treated effluents

meeting the discharge limits for on-shore discharge will be discharged in

nearby nullah/river at controlled rate, if required. Domestic waste water

generated at temporary camp facility in the block will be disposed in septic

tank and soak pits. Therefore, soils of the study area may not undergo any

adverse impact due to discharge and storage in HDPE lined pits and also if any

treated effluents meeting on-shore discharge standards are discharged in

nearby nullah/river or by discharge of treated domestic waste water in soak

pits near drilling sites.

5.4 WATER RESOURCE AND WATER QUALITY

Total water need of 40 m3/d during drilling for nearly 150 days and only 10

m3/d during assessment testing of 5 to 10 days. Therefore, water resources of

the area will not have any adverse impact due to temporary additional water

requirement during drilling and assessment testing operations of the wells in

during 2011-15 periods.

Since the effluents generated during drilling will be stored in shallow HDPE

lined effluent pits, no seepage to ground aquifers can occur. Furthermore,

treated effluents meeting on-shore discharge limits from drilling sites will be

discharged at a low rate in nearby nullah/river, if required. Therefore, no

adverse impact either on ground or surface water quality is likely in the study

area in view of heavy rainfall and perennial rivers with large flow in the block

area.



5.5 CLIMATOLOGY AND METEOROLOGY

There will be no impact of exploratory drilling and assessment testing

operations on climatology and meteorology of the study area.

5.6 AMBIENT AIR QUALITY

Major sources of gaseous pollution from drilling operations will be the

exhaust gases from diesel driven power generators. Major sources of the

gaseous pollution from exploratory testing for oil and gas from the exploratory

wells will be the exhaust gases from flaring of associated gases produced

along with oil for nearly 3 to 4 days at each well. Major pollutants in exhaust

gases from these sources will be SO2 and NOx with some CO, unburnt

hydrocarbons and soot. These will be discharged from stacks of appropriate

heights meeting the statutory requirements. Dispersion and transport of

pollutants discharged in exhaust gases from stacks of appropriate heights

through ambient air in a largely forested area far away from populated area of

villages/towns having an overall population density of only 47.7 persons/km2

are unlikely to have any perceptible adverse impact on the ambient air quality

at a distance beyond 500 m from the emission sources. Since the monitored

24-hourly average concentrations of PM10, PM2.5 ,SO2 and NOx in most

populated villages/towns in the block area are relatively quite low (refer Sub-

section 4.3.5.3 in Chapter 4) and wells are proposed to be drilled away from

populated areas, therefore, some temporary increase in ground level

concentration due to emission of pollutants from stacks of appropriate heights

in a forested hilly area away from populated places due to proposed drilling

and testing operations will have essentially insignificant adverse impact on

ambient air quality in the study area.

Use of few diesel driven vehicles for transport of drilling equipments,

personnel and material will also generate exhaust gases as well as some dust

from unpaved roads. Gaseous pollutants in vehicular exhausts will disperse

quickly. Dust generated due to vehicular movement on unpaved roads will be

relatively coarse and will settle quickly. The impact of vehicular movement is



likely to be confined to a distance of nearly 100 m from the source. Therefore,

PM10, PM2.5, SO2, NOx, CO and hydrocarbons emissions due to vehicular

movement during drilling and testing operations will have essentially no

adverse impact in the study area.

Furthermore, existence of appreciable number of trees with extensive leaf area

in the block area will act as a sink for gaseous and particulate pollutants from

vehicular movement as well as drilling and assessment testing operations.

Since crude oil and/or natural gas likely to be found in the area is expected to

be sweet with essentially no sulphur content, there will be no emission of toxic

H2S to cause any hazard in the drilling area of the exploratory wells.

5.7 NOISE AND VIBRATIONS

Ambient noise levels are likely to increase temporarily over localized area due

to movement of trucks and other vehicles.

The built-in shock absorbing system in rig will reduce vibration and noise

from rotating equipment to ensure that noise level at the periphery of the

drilling well operational area does not exceed 75 dB (A). Noise levels

generated by the operation of DG sets for power supply at drilling site will

also attenuate to about 75 dB(A) at the periphery of the drilling

site/operational area. Assuming that the drilling well site operational area

periphery is at a minimum distance of 20 m from noise sources and noting that

the noise level decreases by nearly 6 dB (A) with each doubling of distance

with no excess attenuation, the noise levels at different distances from a free

field noise level of 75 dB (A) at a distance of 20 m from the source are given

below:

Distance, m 40 80 160 320 640 1280 2560

Noise Level, dB (A) 69 63 57 51 45 39 33

Day-time (Lday) monitored ambient noise levels at populated locations in block

area varies from to 42.5 to 54 (refer Sub-section 4.3.6.4 in Chapter 4).

Therefore, during exploratory drilling and testing, noise levels in populated



areas lying beyond 475 m from drilling site operational area boundary will

remain unaffected during day-time, if baseline noise levels at that position is

43.8 dB(A) or more due to masking effect. Night-time noise levels (Lnight)

monitored in the area varies from 37.2 to 42 dB (A). Therefore, only

populated areas lying much beyond 2637 m from drilling site are expected to

remain unaffected during night-time as a result of drilling operations due to

masking effect. Therefore, only those populated village areas lying within 475

m distance are likely to experience some increase in noise levels during day-

time due to drilling operations if baseline noise levels are less than 47.5

dB(A). However, Lday noise levels in villages will be within the residential

area limit of 55 dB(A) at day-time at a distance beyond 200 m from drilling

site periphery if baseline Lday value is 55 dB(A) or less. Furthermore, Lnight

noise level in village area will be within the residential area limit of 45 dB(A)

at night-time at a distance beyond 640 m if baseline Lnight value is 45 dB(A)

or less at that position.

5.8 LAND USE

Since the land requirement for the drilling is only about 110 m x 150 m (1.65

hectare) at each of the exploratory locations the impact on land use in the

study area is expected to be insignificant since exploratory drilling is likely to

be carried out in non-populated areas only. For drilling location and access

roads falling within the forest area, then necessary permission will be obtained

from District Forest Officer for diversion of forest land for industrial activity

before commencing any drilling activity. It is, however, recommended that the

alignment of access roads and lay-out of drilling site area be so chosen that the

cutting of trees may be minimized to the extent possible.

If any area chosen for exploratory drilling has agricultural crops, the crops

may be affected to some extent due to drilling/testing activities and movement

of vehicles, etc. in the area. In all such cases, OIL will adequately compensate

owners of damaged crops.



5.9 BIOLOGICAL ENVIRONMENT

5.9.1 Terrestrial Flora

The movement of trucks and other vehicles carrying men and material may

require access cutting and clearing of trees in the block area and may,

therefore, require timber salvage. These trucks/vehicles can be easily

maneuvered and removal of tree/shrub/tall grass lying in path can be avoided

to some extent.

Some damage of existing crops at some locations in cultivated area may

become inevitable for carrying out drilling. However, adequate compensation

will be paid to the cultivator by OIL for all such cases depending upon the

extent of crop loss or loss of opportunity of cultivation.

The drilling of the exploratory wells in during 2011-15 period is not likely to

have any significant adverse impact on the flora of the block/study area

because only very few trees are likely to be cut in the block area of drilling

location for the preparation of the drilling sites and for making suitable

passage for the movement of heavy vehicles through the block area to drilling

sites. It is, however, recommended that the lay-out plan of drilling sites and

alignment of passage for vehicle movement at each drilling location should be

so chosen so as to reduce the cutting of trees to bare minimum. OIL will,

however, carry out compensatory plantation through Forest Department of

Aizawl near each drilling site or at other appropriate locations on completion

of drilling and testing, if considered necessary.

Flaring of gas produced during assessment testing will be minimized because

exploratory testing will be carried out only for about 3 to 4 days at each site

and quantity of natural gas likely to be flared will be nearly 10000 m3/d in a

properly designed flare pit.

5.9.2 Terrestrial Fauna

Drilling activities will generate some noise in an area at least upto 500 m from

drilling site. Flaring of gas in a flare during exploratory testing will be fairly

small. Noise due to drilling activity may have some adverse impact on



terrestrial fauna at least upto 500 m from drilling site for the duration of

drilling. However, heat radiation and glare effect, if any, will be significantly

moderated due to existence of dense vegetation cover in forested area around

drilling location.

5.10 DEMOGRAPHIC AND SOCIO-ECONOMIC ENVIRONMENT

Temporary presence of nearly 60 persons in the study area during drilling for a

limited period of nearly 150 days at each site is unlikely to have any adverse

impact on the demographic environment of the thinly populated villages in the

block and surrounding area. No adverse impact can be expected on socio-

economic conditions of the area during the drilling and testing operations. It is,

however, possible that some local persons may find temporary direct

employment as unskilled labour and some more may find indirect employment

for transportation of material and personnel during drilling and testing period

at each location which will be of significant economic support to residents in

the study area having limited job opportunity.

5.11 CONCLUSIONS

The detailed discussions of impact on various attributes of environment due to

drilling and testing operations in previous sections clearly indicate that these

activities will not cause any perceptible damage to environment of the study

area, as delineated below:

No soil erosion;

Insignificant temporary localized air pollution due to exhaust emissions

from the diesel driven power generators needed for drilling rig operation at

the exploratory locations and DG sets for supplying electric power to meet

other project requirements as well as from vehicular movement resulting in

some localized SO2, NOx and dust generation;

No contamination of soils because drilling discharges with nontoxic

materials will be collected in HDPE lined effluent pits;

Insignificant temporary localized generation of small amount of domestic

effluents and solid wastes due to establishment of temporary mobile camp

facilities in the block/area;



Insignificant temporary localized generation of noise due to operation of

power generators, drilling rig and other machines as well as from vehicular

movement;

Insignificant surface or ground water pollution since drilling and testing

effluents will be treated to meet on-shore discharge standards before their

discharge, if any, in nearby nullah/river at controlled rate;

No disruption of water supply or natural drainage;

No impact on local water availability;

No damage to archaeological, cultural or paleontological sites; and

Only small minor temporary impact on flora and fauna in a limited

forested area close to drilling location is anticipated.

Some cutting of trees for site preparation in a maximum land area of nearly

1.65 hectare around each exploratory drilling location as well as in the area

required for making suitable access routes for movement of heavy vehicles

may take place for which adequate compensatory plantation is proposed to be

arranged by OIL through Forest Department, Aizawl. Temporary employment

of some local persons directly as unskilled labour for project activities and

indirect employment for project related work may benefit the local population.

The impact due to drilling of the exploratory wells for exploratory

hydrocarbons production in the block area is summarized below in a tabular

form:

Environmental Attribute/ Project Activity

Impact

Proposed access cutting Some cutting of trees may be inevitable.

Clearing and timber salvage

Cutting of some trees and timber salvage may be necessary.

Wild life and habitat protection

Minor adverse impact upto 500 m from drilling site in forested area is likely.

Fuel storage and handling Insignificant impact.

Camps and staging Insignificant impact since temporary mobile camp facilities in block area will be used. However,



cutting of some trees may be necessary.

Liquid and solid wastes disposal

Insignificant temporary localized impact is likely.

Cultural and archaeological sites

Not applicable.

Selection of sites Two numbers Exploratory drilling sites are identified. The remaining four sites are yet selected.

Terrain stabilization Not applicable.

Protection of fresh water horizons

Not applicable since effluents will be stored in HDPE lined shallow pits and well casing will protect water horizons in the drilled well.

Blowout prevention plan Necessary care will be taken during drilling and blowout preventors will be installed before drilling to take care of any emergency.

Flaring during drilling and production

Ground flare will be used with appropriate control measures.

Abandonment of well Will be applicable only if commercial production of oil and/or gas is unviable from any exploratory well.

Rig dismantling and site completion

Insignificant localized impact in 5 m x 5 m rig area.

Reclamation for abandonment

Not applicable at present.

Noise Insignificant temporary localized impact.

Debris disposal Insignificant localized impact.

Protection of natural drainage and water flow

Natural drainage and water flow will be protected.



CHAPTER 6: RISK ASSESSMENT AND CONSEQUENCE ANALYSIS

6.1 RISK ASSESSMENT, CONSEQUENCE ANALYSIS AND OCCUPATIONAL SAFETY DURING DRILLING AND PRODUCTION TESTING

6.1.1 INTRODUCTION

Hydrocarbon operations are generally hazardous in nature by virtue of

intrinsic chemical properties of hydrocarbons or their temperature or pressure

of operation or a combination of these. Fire, explosion, hazardous release or a

combination of these are the hazards associated with hydrocarbon operations.

These have resulted in the development of more comprehensive, systematic

and sophisticated methods of Safety Engineering, such as, Hazard Analysis

and Risk Assessment to improve upon the integrity, reliability and safety of

hydrocarbon operations.

The primary emphasis in safety engineering is to reduce risk to human life and

environment. The broad tools attempt to minimize the chances of accidents

occurring. Yet, there always exists, no matter how remote, that small

probability of a major accident occurring. If the accident involves

hydrocarbons in sufficient large quantities, the consequences may be serious

to the project, to surrounding area and the population therein.

Derrick floor is the center stage of all the drilling operations and it is most

susceptible to accidents. Safety precautions with utmost care are required to be

taken during drilling as per the prevailing regulations and practices so that

accidents can be avoided. Due to advancement in technology, a number of

equipments have been developed over a period of time to cater the need of

smooth operation on derrick floor. Various standards are required to be

referred to cover the variety of equipments used for safe operation in drilling

and it is desirable to use a properly prepared manual for occupational safety

while working or drilling over a rig. Since drilling of wells is to be carried out

by an expert external agency, safety system for drilling rigs and safe working

conditions and practices to be adopted during drilling operations and those



related to drill stem test, well completion by perforation and well testing and

activation are not discussed in this section. Safety systems for exploratory

production testing are discussed only briefly in this section because the same

will be carried out at each exploratory drilling location. It may, however, be

noted that well testing and exploratory production of hydrocarbons require

proper analysis of hazards involved in production testing operations and

preparation of an appropriate emergency control plan.

6.1.2 IDENTIFICATION OF HAZARDS IN DRILLING AND PRODUCTION TESTING OPERATIONS

Various hazards associated with drilling and testing operations of

hydrocarbons are briefly described in following sub-sections.

6.1.2.1 Minor Oil Spill

A minor oil spill is confined within the well site area. The conditions which

can result in minor oil spill are as follows:

Diesel Fuel Storage System: Oil spillage from tanker unloading, leaking

valves, lines and storage tank.

Exploration or Testing Well Site: Drill stem testing leading to an oil

spillage from lines, valves, separator and tank failure.

During the well testing operation, there exists a possibility of hydrocarbon

gases being released from a failure upstream of crude stabilization facilities at

the exploratory drilling location. Once the flow of oil from well is stopped,

then on-site access for clean-up is possible. If flow from well can not be

stopped, a blowout situation exists.

6.1.2.2 Major Oil Spill

Significant hydrocarbon inventories will not be maintained at a well site since

only exploratory production testing is involved at present for 5 to 10 days at

each well site. A major spill can, therefore, only arise as a result of an

uncontrolled flow from a well either during drilling or exploratory production

test resulting from a failure of the surface equipment.

For this to occur would require a combination of mechanical damage, such as,

ruptured flow line coupled with failure of the emergency shut down (ESD)

system. Oil is produced with some associated gas, therefore, an oil spill arising



from a failure of the surface equipment upstream of the crude stabilization

facilities will result in the release to atmosphere of hydrocarbon vapours

together with oil droplets in the form of a mist.

Provided that ignition does not take place and the well head is not obstructed

the well can be shut in manually at the wellhead. If ignition occurs or other

damage prevents access to the wellhead then a blowout situation exists and

appropriate measures must be implemented.

6.1.2.3 Blowout

Blowout means uncontrolled violent escape of hydrocarbon fluids from a well.

Blowout followed by ignition which prevents access to the wellhead is a major

hazard. Contributors to blowout are:

Primary

Failure to keep the hole full;

Mud weight too low;

Swabbing during trips;

Lost circulation; and

Failure of differential fill-up equipment.

Secondary

Failure to detect and control a kick as quickly as possible;

Mechanical failure of BOP;

Failure to test BOP equipment properly;

Damage to or failure of wellhead equipment;

Failure of casing; and

Failure of formation or cement bond around casing.

If the hydrostatic head exerted by the column of drilling fluid is allowed to

drop below the formation pressure then formation fluids will enter the

wellbore (this is known as a kick) and a potential blowout situation has

developed.

Fast and efficient action by operating personnel in recognizing the above

situations and taking precautionary measure can avert a blowout.

6.1.2.4 Hydrogen Sulphide (H2S)



Hydrogen sulphide gas (H2S) is extremely toxic, even very low concentrations

can be lethal depending upon the duration of exposure. Without any warning,

H2S may render victims unconscious and death can follow shortly afterwards.

In addition, it is corrosive and can lead to failure of the drill string or other

tubular components in a well. Fortunately, crude oil and natural gas is likely to

be sweet, that is, without any sulphur compounds including H2S in the block

area. However, following safety measures may become necessary as and when

H2S is detected while drilling and testing the exploratory wells in the block

area and these are presented.

The Occupational Safety and Health Act (OSHA regulations) has set a 10 ppm

ceiling for an eight hourly continuous exposure (TWA limit), a 15 ppm

concentration for short term exposure limit for 15 minutes (STEL) and a peak

exposure of 50 ppm for 10 minutes for H2S.

Important characteristics of H2S gas are given in the Table 6.1.

6.1.3 CONTROL MEASURES FOR MAJOR HAZARDS

Out of four hazards described in Sub-sections 6.1.2.1 to 6.1.2.4, occurrence of

(a) blowout and (b) sour gas (H2S) are the two major hazards. Occurrence of

H2S along with oil and gas, if detected in any well, is the major hazard during

exploratory production testing of the well. Control measures for occurrence of

blowout and H2S gas are discussed in following sub-sections:

6.1.3.1 Blowout

The precautionary and control measures used for blowout prevention are

discussed below:

A. Precaution Against Blowout

1. The following control equipments for drilling mud system shall be

installed and kept in use during drilling operations to prevent the blowout:

A pit level indicator registering increase or reduction in the drilling

mud volume and shall include a visual and audio –warning device near

the driller stand.

A device to accurately measure the volume of mud required to keep the

well filled at all times.



A gas detector or explosimeter at the primary shale shaker and

connected to audible or visual alarm near the driller stand.

A device to ensure filling of well with mud when the string is being

pulled out.

A control device near driller stand to close the mud pump when well

kicks.

2. Blowout prevention drill shall be carried out once every week near the

well during drilling.

3. Suitable control valves shall be kept available near the well which can be

used in case of emergency to control the well.

4. When running in or pulling out tubing, gate valve and tubing hanger shall

be pre- assembled and kept readily available at the well.

B. Precaution after Blowout

On appearance of any sign indicating the blowout of well, all persons, other

than those whose presence is deemed necessary for controlling blowout, shall

be withdrawn from the well.

During the whole time while any work of controlling a blowout is in progress,

the following precautions shall be taken:

1. A competent person shall be present on the spot throughout.

2. An area within the 500 meters of the well in the down wind direction shall

be demarcated as danger zone.

All electrical installations shall be de-energized.

Approved safety lamps or torches shall only be used within the danger

zone.

No naked light or vehicular traffic shall be permitted within the danger

zone.

3. A competent person shall ascertain the condition of ventilation and

presence of gases with an approved instrument as far as safety of persons

is concerned.



4. There shall be available at or near the place, two approved type of self

containing breathing apparatus or any other breathing apparatus of

approved type for use in an emergency.

5. Adequate fire fighting equipment shall be kept readily available for

immediate use.

C. Blowout Preventor Assembly

To prevent the blow out during drilling operations following steps are taken:

1. After the surface casing is set in a well no drilling shall be carried out

unless blowout preventor assembly is securely installed and maintained.

2. Blowout preventor assembly shall consist of :

On bag type of preventor for closing regardless whether drilling

equipment is in the hole or not.

One blind ram preventor closing against an open hole.

One pipe ram preventor closing against drill pipe in use in the hole.

3. In blow out preventor assembly, there shall be provided two seamless steel

pipes at least 50 mm of diameter connected below each set of blow out

preventor one for bleeding off pressure and the other for killing the well.

These pipes shall be straight and lead directly in the well.

4. Each pipeline shall consist of component having a working pressure equal

to that of the blowout preventor.

D. Blowout Preventor (BOP) Control Units: Location and Conditions

1. BOP control units should be located at a distance of nearly 30 m from well

center.

2. Status of following should be checked and maintained in good condition:

Pressure Gauges;

Pressure steel lines/fire resistant hoses;

Level of hydraulic oil;

Charging of unit; and

Availability of sufficient number of charged bottles.

E. Control System for Blowout Preventors



1. All manual control for manually operated blowout preventor shall be

located at least 0.60 meters out side the derrick substructures. Instructions

for operating the controls shall be posted prominently near the control

wheel.

2. A control of power operated blowout preventor shall be located within

easy reach of driller floor:

3. A remote control panel for blowout preventors shall also be installed

around floor level at a safe distance from the derrick floor.

4. All control for blow out preventors shall be clearly identified with suitable

markers.

6.1.3.2 Control Measures for H2S During Drilling

The following control measures for H2S will become necessary if presence of

H2S is detected at an exploratory well.

A. H2S Detection System Presence

A four channels H2S gas detection system should be provided. Sensors should

be positioned at optimum points for detection, actual locations being decided

on site but are likely to be:

Well Nipple

Rig Floor

Shaker header tank

Substructure cellar

The detection system should be connected to an audio visual (siren and lights)

alarm system. This system should be set to be activated at a concentration of

15 ppm H2S.

The mud logging will have a completely independent detection system which

is connected to an alarm in the cabin. This system will be adjusted to sound an

alarm at a concentration level of 10 ppm H2S as suggested in the Drilling and

Production Safety Code for Onshore Operators issued by The Institute of

Petroleum.

A stock of H2S scavenger will be kept ready at drilling site for emergency use.



B. Small Levels of H2S

Small levels of H2S (less than 10 ppm) will not activate the well site alarms.

Such levels do not create an immediate safety hazard but could be a first

indication of high levels of H2S to follow.

H2S will cause a sudden drop of mud pH. The mud man will, therefore,

organize and supervise continuous pH checks while drilling. Checks should be

as frequent as required depending on ROP and always made following a

formation change.

Following control measures will be taken in case of small level of detection:

Add H2S scavenger to mud.

Check H2S levels at regular intervals for possible increase.

Inform all personnel of the rig about the presence of H2S and current wind

direction.

Commence operations in pairs.

Render sub base and cellar out-of-bounds without further checking levels

in this area.

C. High Levels of H2S

Higher levels of H2S (greater than 10 ppm) do not necessarily cause an

immediate safety hazard. However some risk does exist and, therefore, any

levels grater than 10 ppm should be treated in the same manner. Occurrence

of 10 ppm or greater H2S concentration will sound an alarm in the mud

logging unit.

If higher levels of H2S greater than 10 ppm are found, following steps will be

taken:

One pre-assigned roughneck will go to doghouse and put on breathing

apparatus. All other rig personnel will evacuate the rig and move in up-wind

direction to designated muster point.

Driller and roughneck will return to the rig floor and commence circulating

H2S scavenger slowly.



The level of H2S will be checked in all work areas. H2S scavenger will be

added to the mud and circulated. If H2S levels drop, drilling will be continued

with scavenger in the mud. Approximately 30 % of hydrogen peroxide (H2O2)

solution will neutralize H2S gas in the mud at 20 gallons of H2O2 per 100

barrels of mud.

6.1.3.3 Control Measures for H2S During Production Testing

H2S scavenging chemicals (caustic soda solution, calcium hydroxide or iron

oxide slurry) are to be continuously injected in the recovered gas/oil/formation

water after pressure reduction through choke before sending the same to

separator, if H2S is detected during drilling of any exploratory well.

6.1.4 FIRE FIGHTING FACILITY

As per Oil Industry Safety Directorate (OISD) Standard, August 2000, for the

drilling rigs and well testing following fire fighting system/equipments should

be provided:

Fire water system; and

First aid fire fighting system.

6.1.4.1 Fire Water System

One water tank/pit of minimum capacity of 50 kl should be located at the

approach of the drilling site.

For production testing, one additional tank/pit of 50 kl should be provided.

One diesel engine driven trailer fire pump of capacity 1800 lpm should be

placed at the approach area of drilling site.

One fire water distribution single line with minimum 4 “ size pipe/casing

should be installed at drilling site with a minimum distance of 15 m from

the well.

6.1.4.2 First Aid Fire Fighting Equipments at Drilling Rig



Portable fire extinguisher will be installed as per IS: 2190 on the drilling rig.

The minimum quantities of fire extinguishers at various locations should be

provided as per the following:

Sl. Type of Area Portable Fire Extinguisher

1. Derrick floor 2 nos. 10 kg DCP type extinguisher

2. Main Engine Area 1 no. 10 kg DCP type extinguisher for each

engine

3. Electrical motor/pumps

for water circulation

for mud pump

1 no. 10 kg DCP type extinguisher

4. Mud gunning pump 1 no.10 kg DCP type extinguisher

5. Electrical Control

Room

1 no. 6.8 kg CO2 type extinguisher for each

unit

6. Mud mixing tank area 1 no. 10 kg DCP type extinguisher

7. Diesel storage area 1 no. 50 lit mechanical foam


2 nos. 10 kg DCP type extinguisher

2 nos. sand bucket or ½ sand drum with

spade

8. Lube Storage Area 1 no. 10 kg DCP type extinguisher

1 no. sand bucket

9. Air Compressor area 1 no. 10 kg DCP type extinguisher

10. Fire pump area 1 no. 10 kg DCP type extinguisher

11. Near Dill In-charge

Office

One fire extinguisher/shed with 3 nos. 10 kg

DCP type extinguisher and 2 sand buckets

12. Fire bell near bunk

house




6.2 FIRE FIGHTING EQUIPMENTS FOR PRODUCTION

TESTING FACILITIES

During production testing for an exploratory well, pressure control Christmas

tree at well head to test the well at a controlled rate is placed. A flare pit is to

be kept ready at a suitable place away from the exploration well at a safe

distance as per safety requirement for ground flaring of associated gas

especially in case of gas strike.

A temporary closed grid hydrant system with monitors, hydrant points and fire

hose boxes should be installed to cover the exploratory well as per the need.

Portable fire extinguishers of DCP, mechanical foam and CO2 types of

sufficient capacity and in sufficient numbers along with sand buckets should

be placed at strategic locations at the exploratory drilling location.

Electrical and manual siren systems should be provided close to the

exploratory production testing facility at the exploratory well. Electrically

operated siren of 2000 to 3000 m range along with push buttons at appropriate

location to operate the same should be installed and a manual siren of 1000 m

range should also be available at the exploratory well site for emergency use.

Adequate personal protective equipments including sufficient number of

breathing apparatus are to be kept ready in proper working condition.

It may be noted that the fire station may not be available anywhere near the

exploratory well site in the block area except at major towns, namely, Aizawl

and Serchhip. But these fire stations may require at least ½ to 1 hour to reach

exploratory drilling well location to provide meaningful assistance. It is,

therefore, necessary that adequate fire fighting facilities are kept in operating

condition at the exploratory well site to take care of any emergency.

Assistance for fire fighting can also be taken, if required, from following fire

stations located within 100 km distance from Mizoram block MZ-ONN-

2004/1:

1. Serchhip Fire Station, Mizoram

2. Aizawl Fire Station, Mizoram

For further assistance in an emergency, General Manager (NEF Project) at

Duliajan can also be contacted on telephone No. 0374-2800405.



6.3 MEDICAL FACILITES

Eventhough negligible accident occurs during drilling and production testing

at the well site since observation of necessary safety requirements has to be

strictly followed. However, first aid should be made available at the drilling

site and a 24 hour standby vehicle (ambulance) should also be available at the

well site for quick transfer of any injured personnel to the nearest hospital, in

case an accident occurs and medical emergency arises.

6.4 QUANTATIVE RISK ASSESSMENT

Quantitative risk assessment (QRA) is a formal systemized approach for

hazards identification and ranking. The final rating number provides a relative

ranking of the hazards. Fire and Explosion Index (F&EI) is an important

technique employed for hazards identification process. Consequence analysis

then quantifies the vulnerable zone for a conceived incident. Once vulnerable

zone is identified for an incident, measures can be formulated to eliminate or

reduce damage to plant and potential injury to personnel.

6.4.1 FIRE AND EXPLOSION INDEX & TOXICITY INDEX

Rapid ranking of hazard of an entire installation, if it is small, or a portion of

it, if it is large, is often done to obtain a quick assessment of degree of the risk

involved. The Dow Fire and Explosion Index (F&EI) and Toxicity Index (TI)

are the most popular methods for Rapid Hazard Ranking. These are based on a

formal systematized approach, mostly independent of judgemental factors, for

determining the relative magnitude of the hazards in an installation using

hazardous (inflammable, explosive and toxic) materials.

The steps involved in the determination of the F&EI and TI are:

Selection of a pertinent process unit

Determination of the Material Factor (MF)

Determination of the Toxicity Factor (Th)

Determination of the Supplement to Maximum Allowable Concentration

(Ts)

Determination of the General Process Hazard Factor (GPH)



Determination of the Special Process Hazard Factor (SPH)

Determination of the F&EI value

Determination of the TI value

Determination of the Exposure Area

6.4.1.1 Hazardous Material Identification Methodology

From the preliminary appraisal of Material Safety Data Sheet, it is observed

that both crude oil and natural gas are inflammable and hazardous.

Furthermore, three phase separator (TPS) containing gas, oil and water may

operate at above atmospheric temperature and large quantity (20 kl) of HSD

will be stored at the drilling site. In view of hazards associated with TPS

operation and large storage inventory (20 kl) of HSD, F&EI and TI values

have been computed for these two units, TPS and HSD storage tanks.

In general, the higher is the value of material factor (MF), the more

inflammable and explosive is the material. Similarly, higher values of toxicity

factor (Th) and supplement to maximum allowable concentration (Ts) indicate

higher toxicity of the material. The tabulated values of MF, Th and Ts are

given in Dows Fire and Explosion Index Hazard Classification Guide. For

compounds not listed in Dow reference, MF can be computed from the

knowledge of flammability and reactivity classification, Th can be computed

from the knowledge of the National Fire Protection Association (NFPA) Index

and Ts can be obtained from the knowledge of maximum allowable

concentration (MAC) values. The MF, Th and Ts values are respectively 16, 0

and 50 for crude oil, 21, 0 and 50 for natural gas, and 10, 0 and 50 for HSD.

General process hazards (GPH) are computed by adding the penalties applied

for the various process factor.

Special process hazards (SPH) are computed by adding the penalties applied

for the process and natural factors.

Both General process hazards and Special process hazards corresponding to

various process and natural factors are used with MF to compute F&EI value

and with Th and Ts to compute TI value.



6.4.1.2 F&EI Computation

F&EI value computed for TPS and CTT from GPH and SPH values using the

following formula are given in Table 6.1:

F&EI = MF x [1 + GPH (total)] x [1 + SPH (total)]

6.4.1.3 Toxicity Index (TI)

Toxicity index (TI) is computed from toxicity factor (Th) and supplement to

maximum allowable concentrations (Ts) using the following relationship:

TI = (Th + Ts) x [1 + GPH (total) + SPH (total)]/100

Table 6.2 also gives the toxicity index (TI) value for two units considered

most hazardous at drilling site operational area.

6.4.1.4 Hazards Ranking

Table 6.3 gives the hazard ranking based on F&EI values and also on toxicity

index values. Table 6.2 shows that for the two process units analyzed, the

largest F&EI (48.51) and TI value (1.48) are obtained respectively for TPS in

exploratory production testing area and HSD tank (20 kl) in fuel storage area.

Therefore, both areas have Light Hazard Potential based on F&EI and Low

Hazard Potential based on TI values.

In the present case since hazard potential is light/low, there is no cause for any

concern.

6.4.2 CONSEQUENCE ANALYSIS

Consequence analysis quantifies vulnerable zone for a conceived incident and

once the vulnerable zone is identified for an incident, measures can be

proposed to eliminate damage to plant and potential injury to personnel. For

consequence analysis both units chosen for hazards analysis are considered.

The following likely scenarios considered for hazard analysis

1. Rupture of one of the nozzle of HSD storage tank in fuel storage area.



2. Bursting / catastrophic rupture of a three phase separator (TPS) at

exploratory production testing area.

indicates that these incidents have light/low hazards potential and also have

<10-6 per tank per year frequency of occurrence which will be reduced further

by OIL by ensuring safe design and operating procedures. Therefore, detailed

calculations for vulnerable zone analysis are not considered necessary. It may,

however, be noted that the vulnerable zones for these accident scenarios are

unlikely to extend beyond 40 m from HSD tank dyke or BLEVE fire ball

boundary and, therefore, may not extend much beyond the drilling area plinth

boundary for each of the exploratory well proposed for drilling and testing

during 2007-14 period. Furthermore, well testing is planned for a maximum of

5 to 10 days at each locations, therefore, chances of TPS rupture is further

reduced.

6.4.2.1 Conclusions

Quantitative risk analysis presented above leads to following conclusions:

Storage of HSD in 20 kl HSD storage tank area has a computed F&EI

value of 37.60 and TI value of 1.48 and, therefore, indicates light fire and

explosion hazard as well as low toxicity hazard.

Operation in three phase separator in testing area has a computed F&EI

value of 48.51 and TI value of 1.10 and, therefore, indicates light fire and

explosion hazard as well as low toxicity hazard.

6.4.2.2 Recommendations for Risk Reduction

Hydrocarbon vapour concentration detector should be installed at some

critical locations near three phase separator. Lower flammability limits

(LFL) and upper flammability limits (UFL) for some gaseous

hydrocarbons are as under:

Compound LFL (% in air) UFL (% in air)

Methane 5.0 15.0

Ethane 3.0 12.5

Propane 2.1 9.5

Butane 1.6 8.4



Smoke sensors and thermal detectors may be installed at HSD storage tank

area.

Proper fire fighting system (hydrant and fire extinguishers) must be

provided for drilling rig, exploratory testing and fuel storage area.

Proper deluge system should be provided to all critical units, such as, three

phase separator, HSD storage tank and crude oil storage test tank to avoid

cascading effect of fire.



Table 6.1: Characteristics of H2S Gas

1. H2S is a toxic colourless gas heavier than air.

2. It has an odour of rotten eggs but see ‘point 6’ below.

3. In concentrations greater than 100 ppm, it will cause loss of senses in 3 to 15

minutes and death within 48 hours.

4. In concentrations greater than 600 ppm death occurs in less than 2 minutes.

5. The safe concentration for a normal working period without protection is 10

ppm.

6. In concentration greater than 10 ppm, the oil factory sense to smell the gas is

lost, the need for detectors is apparent.

7. It attacks the body through the respiratory organs.

8. It dissolves in the blood and attacks through the nervous system.

9. It is very irritating for the eyes as it forms sulphurous acid together with water.

10. The Occupational Safety and Health Act (OSHA) sets a 10 ppm ceiling for an

8 (eight) hour continuous exposure (TWA limit), a limit of 15 ppm for short

term exposure limit for 15 minutes (STEL) and a peak exposure concentration

of 50 ppm for 10 minutes.

11. The best protection is breathing apparatus, with mask covering the whole face

and a bottle containing breathing air.

12. It burns with a blue flame to sulphur dioxide which is almost as dangerous as

H2S.

13. It forms an explosive mixture with air at concentrations from 4% to 46%.

14. Short exposure of high tensile steel to as little as 1 ppm in aqueous solution

can cause failures.

15. Concentrations greater than 15 ppm can cause failure to steel harder than

Rockwell C-22. High stress levels and corrosive environments accelerate

failures.

16. When pH is above 9 and solubility is relatively high, it is readily soluble in

mud and especially in oil muds.

17. The compressibility factor (Z) is higher than that for natural gas and H2S will

thus expand at rather lower pressures; or further up in the bore hole than

natural gas.



18. A 35% hydrogen peroxide solution will neutralize H2S gas in the mud or 20

gallons of H2O2 per 100 barrels of mud.

19. It occurs together with natural gas in all oil provinces of the world.

20. In characteristic H2S gas areas concentration above 42% in natural gas have

been reported.

21. H2S may also be formed in significant amounts from the degradation of

modified lignosulphonates at temperatures exceeding 4000F or 2040C.

22. Coughing, eye burning and pain, throat irritation, and sleepiness are observed

from exposure to low concentrations of H2S.

23. Exposure to high concentrations of H2S produces systems such as panting,

pallor, cramps, paralysis of the pupil and loss of speech. This is generally

followed by immediate loss of consciousness. Death may occur quickly from

respiratory and cardiac paralysis.

Table 6.2: Determination of the Fire and Explosion Index and of the Toxicity Index

Crude Oil/Natural Gas in Three Phase

Separator

HSD Storage Tanks

MATERIAL FACTOR (MF) 16/21 10

GENERAL PROCESS HAZARDS (GPH)

Exothermic Reactions (Condensation/Hydrolysis) 0 0

Endothermic Reactions 0 0

Material Handling and Transfer 0 0.50

Process Units within a Building 0 0

Centrifuging 0 0

Limited Access 0 0

Poor Drainage 0.10 0.10

Add: GPH(total) 0.10 0.60

[(1+GPH(total)] x Material Factor = sub-factor 23.1 16.0

SPECIAL PROCESS HAZARDS (SPH)

Process Temperature (use highest penalty only)

- above flash point 0.25 0.25



- above boiling point 0 0

- above auto ignition 0 0

Low Pressure (atmospheric/sub-atmospheric)

- Hazard of Peroxide Formation 0 0

- Hydrogen Collection Systems 0 0

- Vacuum Distillation at less than 0.67 bar abs. 0 0

Operation in or near Flammable Range

- Storage of Flammable Liquids and LPGs outdoor

0 0.50

- Reliance on Instrumentation and/or Air Purging to stay out Flammable Range

0 0

- Always in Flammable Range 0 0

Operating Pressure 0 0

Low Temperature 0 0

- Between 0 and –30 deg. C 0 0

- Below –30 deg. C 0 0

Quantity of Flammable Material

- In Process 0.65 0

- Storage 0 0.50

Corrosion and Erosion 0.10 --

Leakage joints and packing 0.10 0.10

Add: SPH 1.1 1.35

[(1+SPH(total)] x sub-factor = F&EI 48.51 37.60

TOXICITY INDEX TI

Toxicity Factor

(Th) 0 0

(Ts) 50 50

(Ts + Th) ---------- x [(1 + GPH(total) + SPH(total)] = 100 Toxicity Index TI

1.10 1.48

Note 1. The term “process” includes handling as well as storage.

2. For a number of process hazard the penalty to be used is fixed and can be taken from the preceding column “penalty”.



Table 6.3: Hazard Ranking

I. Based on Dow Fire and Explosion Index (F & EI)

F & EI Value Hazard Ranking

1-60 Light

61-96 Moderate

97-127 Intermediate

128-158 Heavy

159-up Severe

II. Based on Toxicity Index (TI)

TI Value Hazard Ranking

< 6 Low

6 – 10 Moderate

10 – up High

Table 6.4: Tolerable Radiation Intensities For Various Objects

Object Tolerable Radiation Intensity (kW/m2)

Drenched Tank 38

Special Buildings (No windows, fire

proof doors)

25

Normal Buildings 14

Vegetation 10-12

Escape Route 6 (upto 30 seconds)

Personnel in Emergencies 6 (upto 30 seconds)

Plastic Cables 2

Stationary Personnel 1.5



Table 6.5: Damage Due to Incident Radiation Intensity

Incident Radiation Intensity (kW/m2)

Type of Damage

62 Spontaneous ignition of wood

38 Sufficient to cause damage to process equipment

25 Minimum energy required to ignite wood at infinitely long

exposure (non piloted)

12.5 Minimum energy required for piloted ignition of wood,

melting of plastic tubing, etc.

4.5 Sufficient to cause pain to personnel unable to reach cover

within 20 seconds, blistering of skin (1st degree burns) is

likely.

1.5 Will cause no discomfort for exposure upto 60 seconds.



CHAPTER 7: DISASTER MANAGEMENT PLAN

7.1 INTRODUCTION

For meeting the emergencies caused by major accidents, planning response

strategies are termed as Disaster Management Plans (DMPs). DMPs cannot

be considered in isolation or act as a substitute for maintaining good safety

standards in a plant. The best way to protect against major accidents

occurrence is by maintaining very high levels of safety standards.

Generally, the following five phases are involved in an emergency:

Discovery and Notification: An event with an imminent threat of turning into

an accident must first be discovered and the discoverer quickly notifies the

same to the plant safety officer.

Evaluation and Accident Control Initiation: Based on the evaluation of

available information, the safety officer makes a rapid assessment of the

severity of the likely accident and initiates the best course of action.

Containment and Counter Measures: Action is first taken to contain

and control the accident by eliminating the causes which may lead to the

spread of accident. Measures are also taken to minimize the damage to

personnel, property and environment.

Cleanup and Disposal: After the accident is effectively contained and

controlled, the cleanup of the site of the accident and safe disposal of

waste generated due to the accident are undertaken.

Documentation: All aspects of accidents, including the way it started and

progressed as well as the steps taken to contain and the extent of the

damage and injury, must be documented for subsequent analysis of

accident for prevention in future, damage estimation, insurance recovery

and compensation payment. It may be noted that some aspects of

documentation, such as, photographs of the site of accident and main

objects involved in the accident, survey for damage estimation, etc. may

have to be carried out before the cleanup and disposal phase. However,

the effort in all cases is to recommence the operation as soon as possible.



7.2 CRISIS MANAGEMENT TEAM OF OIL

OIL has developed on site and off site emergency plan. These plans will

consider linkages with local administration, local communities, Forest and

Wildlife Departments and other operators in the area to provide necessary

support to OIL to manage the emergency and also to disseminate information

on the hazards associated with the emergency.

OIL already has a competent and well trained Crisis Management Team

constituted at its NEF Project Office at Duliajan and the same can take control

of the situation at drilling site in Mizoram block, if necessary, soon after

receiving the information from drill site. Contact person and telephone number

at Duliajan for any emergency are:

General Manager (NEF Project), Duliajan

Telephone No.: 0374-2800405

Oil will set up emergency response team in Mizoram

Even though OIL follows well formulated safety guidelines and emergency

response procedures as per the detailed regulations given in the Oil Mines

Regulation 1984 and Oil Industry Safety Directorate Standard 2000, but it is

still considered appropriate to provide a brief outline of a desirable on-site

Disaster Management Plan (DMP) to augment the procedures followed by

OIL, if considered necessary. Proposed on site DMP is discussed in the

following sub-sections.

7.3 EMERGENCY CLASSIFICATION

Severity of accident and its likely impact area will determine the level of

emergency and the disaster management plan required for appropriate

handling of an emergency. Emergency levels and the action needed for each

level are indicated below:

7.3.1 Level 1 Emergency

A local accident with a likely impact only to immediate surroundings of

accident site, such as, local fires and limited release of inflammable material.

The impact distance may not be more than 15 m from the site of primary



accident and may require evacuation of the building/area where accident

occurred and utmost the adjacent building/area.


A major accident with potential threats to life and property upto 500 m

distance requiring the evacuation of all personnel from the threatened area

except the emergency response personnel. Larger fires, release of large

quantities of inflammable materials may belong to emergency level 2.


An accident involving a very serious hazard and with likely impact area

extending beyond 500 m from the operational area, that is, drilling area limits,

such as, major fire, very large release of inflammable material. Major fires

will usually have the triggering effect resulting in the propagation of

explosion. In a level 3 emergency, evacuation of population in villages, if any,

adjoining the operational area may sometime become necessary if threatened

area extend to populated village area adjoining the site of the primary accident

in a direction of maximum impact.

On-site Disaster Management Plan (DMP) will meet the hazards created due

to all Level 1 emergencies and most of the Level 2 emergencies. In addition to

on-site DMP, off-site DMP may also have to be put into operation for some

Level 2 and all Level 3 emergencies.

7.4 METHODOLOGY OF DMP PREPARATION

A DMP is usually prepared in two parts: On-site DMP and Off-site DMP. The

On-site DMP is administered by the owner or occupier of the hazardous

plant/installation, OIL in the present case. OIL management may seek the

assistance of other agencies, namely, fire brigade, police and health

authorities, if considered necessary. The Off-site DMP is normally

administered by the District Magistrate with the assistance of other relevant

authorities.

Luckily the maximum vulnerable zone may not extend much beyond

exploratory drilling and testing area due to BLEVE around TPS area and fire

around HSD storage area in a sparsely populated area around chosen drilling

locations. Therefore, Level 3 Emergency requiring evacuation of surrounding



village population is not applicable in case of drilling and testing area. Even

the Level 2 emergency is likely to be confined within a limited distance from

the TPS area and HSD storage area, the evacuation of personnel only from

affected area will be required. Even under the worst accident scenario,

evacuation of less than 30 persons may be involved and damage, if any, to

nearby installations is expected to remain confined within the operational area.

7.5 ON-SITE DISASTER MANAGEMENT PLAN

7.5.1 Site Main Controller

Fig. 7.1 depicts the organizational setup for the on-site DMP. The Party Chief,

or the senior most officer in the absence of the Party Chief, will lead this

organization as the Site Main Controller (SMC). The SMC will have the

following two teams working under him:

Site Incident Controller Team

Auxiliary Team

7.5.2 The Site Incident Controller Team

This team will be lead by the Site Incident Controller (SIC) and will consist of

five supervisors and other supporting personnel. The Site Emergency

Controller, or in his absence the HSE Supervisor, will act as SIC. As far as

possible, the supervisors should be drawn from the unit in which the primary

accident has occurred.

7.5.3 The Auxiliary Team

This team will be lead by the Auxiliary Team Controller (ATC) and will

consist of five supervisors and other supporting personnel. The Manager-

Administration and Security, or in his absence Administrative Officer will act

as ATC.

7.5.4 Responsibilities of Site Main Controller (SMC)

The responsibilities of SMC will be as under:

Set up Emergency Control Centre (ECC) to direct emergency operations.

Determine the severity of an accident, declare appropriate emergency

level and changing the emergency level, if considered essential.

Exercise direct control of units not affected by accident.



Determine most probable course of events by continuously reviewing and

assessing the developments.

Direct the safe shutting down of the installations in consultation with SIC,

ATC and other important officers, if necessary.

Ensure proper evacuation and treatment to injured personnel.

Liaison with District Magistrate, Police, Fire Brigade and other agencies,

if necessary.

Maintain emergency logbook.

Issue authorized statements to media.

Look after safe operation of the plant and rehabilitation of affected

persons.

Declare all clear situation after the emergency is cover.

7.5.5 Responsibilities of Site Incident Controller (SIC)

The responsibilities of SIC be as under:

Assess the severity of the accident.

Initiate emergency actions to ensure the safety of personnel and minimum

damage to the installations and material.

Direct rescue and fire fighting operation.

Search for casualties.

Evacuation of non-essential personnel to assembly area.

Setup communication with SMC and ATC.

Look after the responsibilities of SMC in his absence.

Give information and advice to external emergency services working at

the site.

7.5.6 Responsibilities of Auxiliary Team Controller (ATC)

The responsibilities of ATC will be as under:

Provide all possible services to SIC so as to enable him to concentrate

fully to handle the emergency.

Provide first aid to injured persons.

Evacuate seriously injured persons to hospitals.

Ensure safe shut down of the installations, if necessary.



Direct precautionary measures to eliminate propagation of accident in

unaffected areas.

Ensure availability of water, power, necessary equipments and materials

for tackling emergency.

Organize an efficient communication system within the project site and

between project site and outside agencies.

Regulate movement of emergency services in and out of the operational

area.

7.5.7 Responsibilities of SIC Supervisors

Five SIC supervisors will have the following responsibilities:

S1 - Control of emergency including fire fighting

S2 - Search, rescue and evacuation.

S3 - Communication with Emergency Control Centre.

S4 - Liaison with external emergency services, if required.

S5 - Available for deployment as per the need.

7.5.8 Responsibilities of ATC Supervisors

A1 - First aid to injured personnel.

A2 - Evacuation of seriously injured persons to hospital.

A3 - Ensure safe shut down of the installations and take steps to prevent

propagation of accident.

A4 - Ensure availability of critical facilities, equipments and materials for

tackling emergency.

A5 - Communication within the plant and with outside agencies.

7.5.9 Warning System

A high pitch warning system may be installed at exploratory drilling and

testing site for announcing the emergency and giving the all clear signal. SMC

will declare the emergency level and operational personnel and, if necessary,



public in surrounding villages will be notified about the nature of the

emergency by using alarm system in the following manner:

Level 1 Emergency – Single beep every five seconds

Level 2 Emergency – Double beep every five seconds

Level 3 Emergency – Continuous wailing of alarm

7.5.10 Emergency Plan Initiation

On declaration of emergency, SMC, SIC and ATC will take charge in their

respective control rooms and confer with one another about the best way to

deal with the emergency. Emergency response personnel will report to their

respective control centers and immediately take charge of their duties as

enumerated in Sections 7.5.4 to 7.5.8. It is of paramount importance that the

measures to contain and control the accident as well as those for rescue and

evacuation are implemented immediately.

7.5.11 Emergency Procedures

7.5.11.1 Level 1 Emergencies

Accident is small and isolated and may not require the shut down of any

installation/unit at the drilling/testing site. Effort shall be made to arrest its

propagation. Level 1 fire may be extinguished with water, sand, earth or fire

extinguishers. Level 1 hazardous chemical release, if any, can be contained

and controlled quickly without requiring shut down of any installation/unit or

the evacuation of persons working in the affected area.


The affected unit will be brought to a safe shut down while continuing

emergency supplies of water and power. Level 2 fires will be extinguished by

mobilizing fire tenders and foam extinguishers. Level 2 hazardous chemical

release, if any, will require evacuation of personnel including those working in

downwind direction towards upwind or cross wind direction to minimize the

injurious effect of hazardous gas release.




Level 3 emergencies are not applicable to drilling and testing operational area

as indicated in Section 7.3.

7.5.12 Accident Site Clean Up

While cleaning the site after explosion and fire accidents, care shall be taken

against the probability of fire of flammable material lying buried in the debris

of fire accident. Information regarding the cleaning up of spills of hazardous

materials, if used, is available in material safety data sheets.

7.5.13 Emergency Response Personnel Safety

All emergency response personnel from the OIL and outside agencies shall

enter the accident site under instruction of SIC. These persons shall invariably

wear appropriate protective gear, such as, fire suits, helmets, boots, respirators

and gas masks, before entering the accident site.

7.6 ALL CLEAR SIGNAL AND PUBLIC STATEMENT

For Level 1 and 2 emergencies Site Main Controller will authorize an all clear

signal in the form of long high pitched alarm with intermittent pauses, say,

two minutes alarm followed by one minute pause repeatedly. Public

statements regarding the emergency will be issued only by SMC.



CHAPTER 8: ENVIRONMENTAL MANAGEMENT PLAN

8.1 INTRODUCTION

After the Environmental Impact Assessment process of the proposed

exploratory drilling and assessment testing operations for the wells, it is

essential to identify project specific actions for implementation during

exploratory drilling and assessment testing operations. These actions are

compiled in the form of an Environment Management Plan (EMP) which

delineates the mitigation measures. Though most of the environmental impacts

identified in the proposed exploratory drilling and assessment testing are

temporary and localized, project specific recommendations are given below

for implementation.

8.2 MITIGATIVE MEASURES FOR MINIMISING

ENVIRONMENTAL IMPACTS

8.2.1 General Measures Required During Drilling and Assessment

Testing

The following environmental management requirements are to be

implemented by the exploratory drilling and production testing personnel:

1. Cutting of trees/shrubs/tall grasses and damage to agricultural crops should

be avoided as far as possible.

2. Any loss of agricultural crops due to drilling activities should be

compensated.

3. Khawnglang Wildlife Sanctuary lies in the south-eastern part of the block

area and no drilling activity should be carried out by OIL in the same. In

the forested area chosen for drilling necessary approvals from Chief

Conservator of Forests, Mamit, Aizawl, Serchhip and Lunglei districts,

shall be taken for the entries into designed forest areas and felling of

minimum number of trees necessary for carrying out exploratory/appraisal

drilling at each location. Compensatory afforestation should also be

planned close to each drilling site through District Forest Departments as

per the statutory requirements.



4. Domestic waste water as well as food left-over and other organic solid

wastes generated in temporary camp facilities at operational area should be

disposed off in safe manner as per the approved procedures.

5. Appropriate arrangements should be made for sewage disposal for

maintaining hygienic conditions at temporary camp facilities site for

exploratory drilling and production testing personnel.

6. Plastic and other hazardous wastes, such as, spent batteries and waste oil,

should be disposed off as per approved safe procedures.

7. Transfer of HSD required for trucks/vehicles from storage tank or road

tanker should be leak proof to avoid contamination of soil by HSD.

8. Only HSD of low sulphur (0.25% maxm.) content should be used for DG

sets and vehicles needed during exploratory drilling and assessment testing

operations.

9. Persons working in high noise area should be advised to use ear

muffs/plugs.

10. Whenever ambient dust levels in work area become very high and above

the safe limit due to natural cause and/or exploratory drilling and testing

activities, workers should be encouraged to use dust mask.

11. Workers should not engage in hunting of any wild animal/bird for their

meat in the exploratory drilling and adjoining areas.

12. Local persons should be engaged preferably as unskilled and/or semi-

skilled labour during project period as far as possible.

8.2.2 Specific Measures Required During Exploratory Drilling and

Production Testing

The following environmental management measures are to be implemented by

exploratory drilling and assessment testing personnel:

1. Drilling discharges (rock cuttings) and wasted drilling fluid (WBM) shall

always be discharged in HDPE lined impervious shallow effluent pits to be

constructed near shale shaker of WBM treatment and recycling system at

drilling site.



2. On-shore discharge standards should always be met before discharging

any treated liquid effluent from effluent pits to nearby nullah/river. The

discharge should be at a controlled rate to ensure that the water quality of

the nullah/river as a result of discharge of treated effluents is not adversely

affected. The treated water from ETP will be recycled and will be used for

drilling activities.

3. Because of bedded nature fissility and high angle of dip there may be

requirement of grouting in the ETP pits to prevent leaching and

contamination of soil and water. .

4. Consumption of water for drilling activities should be minimized which

will automatically minimize liquid effluent generation rate. Since the

drilling action will require huge amount of water and exploiting ground

water seems to be a difficult proposition and only viable option is to tap

the monsoonal flow by constructing a series of check dams along the

feeder channels.

5. Oil based mud, if used during emergency, should not be discharged in the

effluent pits. It should be stored in steel barrels and brought to the base

camp for proper disposal.

6. On completion of exploratory drilling and testing of the well, all drill

cuttings and other oily solid wastes after requisite treatment should be put

in HDPE lined effluent pit, covered on top with HDPE sheet and then with

a thick layer of soil and sealed to form a mound with proper slope to

prevent rainwater seepage and water source contamination in nearby area.

7. In order to avoid any adverse impact on populated areas of villages, it is

desirable to choose drilling locations at 500 m or more but in no case less

than 300 m from such an area.

8. Compensatory plantation through the district forest department should be

carried out if cutting of significant number of trees and shrubs at road side,

agricultural fields and community places becomes necessary.



8.2.3 Environmental Monitoring

Monitoring programme is summarized below and should be finalized in

consultation with Assam State Pollution Control Board to meet the

requirement during exploratory drilling/testing.

Sl. No. Description Number of Locations

Parameter to be Monitored

Frequency

1. Ambient Air Quality

3 near operational area

As per MPCB and CPCB guidelines

Quarterly

2. Water Quality 3 to 4 near exploratory well drilling


Quarterly

3. Soil Quality 2 to 3 near exploratory well drilling


Quarterly

4. Noise Level 2 to 3 near operational area


Quarterly

Post project monitoring programme will depend upon the techno-commercial

viability of hydrocarbons production from the exploratory well. If economic

quantities of hydrocarbons are not found, then the drilled well will be plugged,

clearly identified at site and abandoned after reinstating the drilling site to its

near original condition and handing over the same to its owner. Until such

time, the monitoring programme summarized above will continue by OIL. If

economic quantities of hydrocarbons are found, the well will be suspended

with a well head/X-mas tree in place, but all other equipment and material will

be removed from the site. HDPE lined Secured Pits will be covered with a top

HDPE liner of 1500 microns. The pit will then be backfilled with minimum of

300 mm compacted layer of local top soil to seal the pits as per the regulatory

requirement. Further monitoring programme will be decided on the basis of

further drilling requirement for hydrocarbons production in the area after

obtaining environmental clearance for developmental activities from MoEF.

8.2.4 Occupational Health Surveillance Programme



Exploration and production (E&P) activities do not have any specific

occupational health hazards and OIL has proposed to provide health

surveillance programme for the officers and workers engaged for exploratory

drilling/testing operations consisting of the following:

1. General Health Check-up.

2. Health Awareness Instructions and Suggestions.



CHAPTER 9: CONSULTANTS ENGAGED Environmental Impact Assessment study for proposed EXPLORATORY DRILLING IN

BLOCK MZ-ONN-2004/1(MIZORAM) of OIL INDIA LTD. DULIAJAN, ASSAM was

conducted by GREEN TECH Environmental Engineer & Consultants, Assam(Sl.No.165 of

QCI/NABET List of Applicants). GREENTECH Environmental Engineer & Consultants was

set up in the year 1997-98 to fill up the need of environmental parameter monitoring services.

The organization started its activities from Sivasagar town in the upper Assam district of

Sivasagar and later set up a branch office in Guwahati during 2000-2001. GREENTECH

Environmental Engineer & Consultants is offering Environmental Consultancy Services in

different sectors spread over the entire North Eastern states. The following personnel were

involved in preparing the present report:

SL. NO. NAME QUALIFICATION

1 Mr. Pranjal Buragohain BE (Civil)

2 Dr.(Mrs.) Belinda Lahon Buragoahin PhD (Science)

3 Mr. Soumyendra Nath Dutta M.Sc. (Agri. Botany)

4 Mr. Paresh Chandra Baruah BE (Chemical)

5 Dr. Ratul Mahanta PhD (Social Science)

6 Mr. K. G. Dev Krori BE (Civil)

7 Mr. Khira Saikia BE (Chemical)

8 Mr. Devendra Nath Kalita BE (Civil)

9 Mr. Himanshu Phukan BE (Chemical)

10 Dr. Debraj Das PhD (Economics)

11 Mr. Sanjib Rajkhowa B.Sc. (Geology)

12 Mr. Rupam Baruah B.Sc. (Chemistry)

13 Mr. Abhijit Rajkonwar HS

TABLE 4.4 WATER QUALITY IN THE STUDY AREA

Sl. No. Characteristics Unit

Ground Water Surface Water FROM PUBLIC WATER POINT CONSTRUCTED BY SOIL DEPARTMENT N 230 41 41" E920 53 46" (Road KEIFANG to AIZAL)

Darlung Road N 230 30 18" E 920 37 24"

Turial River in Turial (N 230 43 39" E92 48.214)

Tlawng (N 230 31ˊ 32" E 920 38ˊ 18")

River GW1 GW2 SW1 SW2

1. Colour -- Colourless Colourless Colourless

Colourless

2. Odour -- Odourless Odourless Odourless Odourless

3. pH -- 6.9 7.2 6.9 7.78 4. Total Hardness (as

CaCO3) mg/l 116 124 62.5 92

5. Iron mg/l 0.26 0.21 .12 .14 6. Chlorides as Cl mg/l 36.9 39.8 12.6 16 7. Total Dissolved Solids

(TDS) mg/l 166 188 102

8. Calcium as Ca mg/l 19.2 22.4 9.66 9.36 9. Magnesium as Mg mg/l 16.6 16.6 8.34 14.6 10. Sulphate as SO4 mg/l 2.5 5.8 4.4 3.6 11. Nitrate as NO3 mg/l .321 .264 .198 .136 12. Total Alkalinity as CaCO3 mg/l 110 120 86.8 59.8 16. Phosphate as PO4 mg/l 0.29 0.30 .075 .05 17. Dissolved Oxygen mg/l 1.4 1.64 6.4 6.2 18. BOD mg/l 3.2 2.8 1.1 2.4 20. Total Suspended Solids

(TSS) mg/l 40 24 112 54.4

Water samples were collected on 7th & 8th April 2011

TABLE 4.1: SOIL CHARACTERISTICS IN STUDY AREA

Sl. No. Parameters

Unit Serchhip Khwalailung Buarpui Thenzawl Chhingchhip Tlungvel Aibawk Sialsuk S1 S2 S3 S4 S5 S6 S7 S8

Physical Parameters 1. Colour -- Brown Light Brown Greenish Grey Brown Gray Gray Gray Light Brown 2. Moisture Content % 3.1 2.4 2.6 2.7 2.5 3.1 2.6 2.8 3. Water Holding

Capacity % 32.6 31.4 32.6 33.1 33.6 32.2 31.9 32.7

4. Bulk Density g/cc 1.21 1.22 1.36 1.27 1.14 1.16 1.22 1.15 Chemical Parameters 5. pH -- 6.6 6.5 6.9 6.7 6.5 6.4 6.6 6.7 6. Calcium (as Ca+) mg/100g 11.2 19.2 16.8 14.4 18.4 19.2 20.0 19.2 7. Magnesium (as Mg+) mg/100g 5.9 5.8 6.3 4.9 3.9 5.8 5.4 5.4 8. Chloride mg/100g 15.6 18.5 19.9 17.0 22.7 18.5 18.5 15.6 9. Total Alkalinity mg/100g 150 110 120 130 120 150 140 130 10. Available Phosphorous mg/100g 3.6 6.6 7.8 6.6 7.0 6.0 5.0 6.0 11. Sulphate mg/100g 4.5 4.8 4.6 5.1 5.8 6.2 6.5 7.7 12. Potassium (as K) mg/100g 29.7 11.7 20.8 27.8 21.4 23.9 24.5 26.2 13. Kjeldahl Nitrogen (as

N) % w/w 0.098 0.118 0.102 0.076 0.104 0.050 0.102 0.075

14. Organic Carbon % 0.21 0.22 0.22 0.20 0.22 0.20 0.23 0.23 15. Organic Matter % 0.36 0.38 0.38 0.34 0.38 0.34 0.40 0.40 16. Cation Exchange

Capacity meq/100g 11.62 12.47 13.10 15.54 12.52 14.35 10.40 9.25

(draft) eia report for exploratory drilling - oil india ltd

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