project report ongc

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1 | D E V A N A N D J H A ( 0 0 1 1 3 1 0 3 6 1 1 ) G G S I P U D E L H I

ABOUT THE COMPANY

Oil and Natural Gas Corporation Limited (ONGC) is

an Indian multinational oil and gas company headquartered in

Dehradun, India. It is a Public Sector Undertaking (PSU) of the

Government of India, under the administrative control of the Ministry

of Petroleum and Natural Gas. It is India's largest oil and gas

exploration and production company. It produces around 69% of

India's crude oil (equivalent to around 30% of the country's total

demand) and around 62% of its natural gas.On 31 March 2013, its market capitalisation was INR 2.6 trillion (US$

48.98 billion), making it India's second largest publicly traded

company. In a government survey for FY 2011-12, it was ranked as the

largest profit making PSU in India. ONGC has been ranked 357th in

the Fortune Global 500 list of the world's biggest corporations for the

year 2012. It is ranked 22nd among the Top 250 Global Energy

Companies by Platts.ONGC was founded on 14 August 1956 by Government of India, which

currently holds a 69.23% equity stake. It is involved in exploring for

and exploiting hydrocarbons in 26 sedimentary basins of India, and

owns and operates over 11,000 kilometers of pipelines in the country.

Its international subsidiary ONGC Videsh currently has projects in 15

countries. ONGC has discovered 6 of the 7 commercially-producing

Indian Basins, in the last 50 years, adding over 7.1 billion tonnes of In- place Oil & Gas volume of hydrocarbons in Indian basins. Against a

global decline of production from matured fields, ONGC has

maintained production from its brownfields like Mumbai High, with

the help of aggressive investments in various IOR (Improved Oil

Recovery) and EOR (Enhanced Oil Recovery) schemes. ONGC has

many matured fields with a current recovery factor of 25-33%. Its

Reserve Replacement Ratio for between 2005 and 2013, has been more

than one.[1] During FY 2012-13, ONGC had to share the highest ever




under-recovery of INR 494.2 million (an increase of INR 49.6 million

over the previous financial year) towards the under-recoveries of Oil

Marketing Companies (IOC, BPCL and HPCL).

PROFILE

ONGC is world's no.3 E&P Company as per prestigious Plattsranking and is 22nd among Platts Top 250 global companies

o Ranked 21st among global Oil and Gas Operations industry inForbes Global 2000 list of the World's biggest companies for 2014;Ranked 176 in the overall list - based on Sales (US$ 29.6 billion),

Profits (US$ 4.5 billion), Assets (US$ 53.8 billion) and MarketValue (US$ 46.4 billion).

o Only Indian energy major in Fortune's Most Admired List 2014under 'Mining, Crude Oil Production' category (No. 7 worldwide -Up 3 places from previous year)

o

Stands at 369 in Fortune Global 500 for year 2013

o Ranked 39 among the world's 105 largest listed companies in

'transparency in corporate reporting' by Transparency Internationalmaking it the most transparent company in India

o Ranked 386 in the Newsweek Green Rankings 2012 Global 500Companies

HISTORY

1947 – 1960During pre-independence, the Assam Oil Company in the North-

Eastern and Attock Oil company in North-Western part of undividedIndia were the only oil companies producing oil in the country. Themajor part of Indian sedimentary basins was deemed to be unfit fordevelopment of oil and gas resources.Aft.er independence, the Government realized the importance of oiland gas for rapid industrial development and its strategic rolein defence. Consequently, while framing the Industrial PolicyStatement of 1948, the development of the hydrocarbon industry in the

country was considered to be of utmost necessity.




Until 1955, private oil companies mainly carried out exploration ofhydrocarbon resources of India. Assam Oil Company was producingoil at Digboi, Assam (discovered in 1889) and the Oil India Ltd. (a 50% joint venture between Government of India and Burmah Oil Company)was engaged in developing two fields Naharkatiya and Moran inAssam. In West Bengal, the Indo-Stanvac Petroleum project (a jointventure between Government of India and Standard Vacuum OilCompany of USA) was engaged in exploration work. The vastsedimentary tract in other parts of India and adjoining offshoreremained largely unexplored.In 1955, Government of India decided to develop the oil and naturalgas resources in the various regions of the country as part of Public

Sector development. With this objective, an Oil and Natural GasDirectorate was set up in 1955 under the then Ministry of NaturalResources and Scientific Research. The department was constitutedwith a nucleus of geoscientists from the Geological survey of India.A delegation under the leadership of Mr. K D Malviya, the thenMinister of Natural Resources, visited several countries to study the oilindustry and to facilitate the training of Indian professionals forexploring potential oil and gas reserves. Foreign experts from USA,

West Germany, Romania and erstwhile USSR visited India and helpedthe government with their expertise. Finally, the visiting Soviet expertsdrew up a detailed plan for geological and geophysical surveys anddrilling operations to be carried out in the 2ndFive Year Plan (1956-57to 1960-61).In April 1956, the Government of India adopted the Industrial PolicyResolution, which placed mineral oil industry amongst the Schedule 'A'industries, the future development of which was to be the sole and

exclusive responsibility of the state.Soon, aft.er the formation of the Oil and Natural Gas Directorate, it became apparent that it would not be possible for the Directorate withlimited financial and administrative powers to function efficiently. Soin August, 1956, the Directorate was raised to the status of acommission with enhanced powers, although it continued to be underthe government. In October 1959, the Commission was converted intoa statutory body by an act of Parliament, which enhanced powers of the

commission further. The main functions of the Oil and Natural Gas




Commission subject to the provisions of the Act, were "to plan, promote, organize and implement programmes for development ofPetroleum Resources and the production and sale of petroleum and petroleum products produced by it, and to perform such other functionsas the Central Government may, from time to time, assign to it". Theact further outlined the activities and steps to be taken by ONGC infulfilling its mandate.

1961 – 1990

Since its inception, ONGC has been instrumental in transforming thecountry's limited upstream sector into a large viable playing field, withits activities spread throughout India and significantly in overseasterritories. In the inland areas, ONGC not only found new resources in

Assam but also established new oil province in Cambay basin(Gujarat), while adding new petroliferous areas in the Assam-ArakanFold Belt and East coast basins (both inland and offshore).ONGC went offshore in early 70's and discovered a giant oil field inthe form of Bombay High, now known as Mumbai High. Thisdiscovery, along with subsequent discoveries of huge oil and gas fieldsin Western offshore changed the oil scenario of the country.Subsequently, over 5 billion tonnes of hydrocarbons, which were

present in the country, were discovered. The most importantcontribution of ONGC, however, is its self-reliance and developmentof core competence in E&P activities at a globally competitive level.

After 1990The liberalized economic policy, adopted by the Government of Indiain July 1991, sought to deregulate and de-license the core sectors(including petroleum sector) with partial disinvestments of governmentequity in Public Sector Undertakings and other measures. As a

consequence thereof, ONGC was re-organized as a limited Companyunder the Company's Act, 1956 in February 1994.Aft.er the conversion of business of the erstwhile Oil & Natural GasCommission to that of Oil & Natural Gas Corporation Limited in 1993,the Government disinvested 2 per cent of its shares through competitive bidding. Subsequently, ONGC expanded its equity by another 2 percent by offering shares to its employees.During March 1999, ONGC, Indian Oil Corporation (IOC) - a

downstream giant and Gas Authority of India Limited (GAIL) - the




only gas marketing company, agreed to have cross holding in eachother's stock. This paved the way for long-term strategic alliances bothfor the domestic and overseas business opportunities in the energyvalue chain, amongst themselves. Consequent to this the Governmentsold off 10 per cent of its share holding in ONGC to IOC and 2.5 percent to GAIL. With this, the Government holding in ONGC came downto 84.11 per cent.In the year 2002-03, aft.er taking over MRPL from the A V BirlaGroup, ONGC diversified into the downstream sector. ONGC has alsoentered the global field through its subsidiary, ONGC Videsh Ltd.(OVL). ONGC has made major investments in Vietnam, Sakhalin,Columbia, Venezuela, Sudan, etc. and earned its first hydrocarbon

overseas revenue from its investment in Vietnam.SynopsisONGC was set up under the visionary leadership of Pandit Jawahar Lal Nehru. Pandit Nehru reposed faith in ShriKeshavDevMalviya who laidthe foundation of ONGC in the form of Oil and Gas division, underGeological Survey of India, in 1955. A few months later, it wasconverted into an Oil and Natural Gas Directorate. The Directorate wasconverted into Commission and christened Oil & Natural Gas

Commission on 14th August 1956. In 1994, Oil and Natural GasCommission was converted in to a Corporation, and in 1997 it wasrecognized as one of the Navratnas by the Government of India.Subsequently, it has been conferred with Maharatna status in the year2010.Over 56 years of its existence ONGC has crossed many a milestone torealize the energy dreams of India. The journey of ONGC, over theseyears, has been a tale of conviction, courage and commitment. ONGCs’

superlative efforts have resulted in converting earlier frontier areas intonew hydrocarbon provinces. From a modest beginning, ONGC hasgrown to be one of the largest E&P companies in the world in terms ofreserves and production.ONGC as an integrated Oil & Gas Corporate has developed in-housecapability in all aspects of exploration and production business i.e.,Acquisition, Processing & Interpretation (API) of Seismic data,drilling, work-over and well stimulation operations, engineering &




construction, production, processing, refining, transportation,marketing, applied R&D and training, etc.Today, Oil and Natural Gas Corporation Ltd. (ONGC) is, the leader inExploration & Production (E&P) activities in India having 72%contribution to India’s total production of crude oil and 48% of natural

gas. ONGC has established more than 7 Billion Tonnes of in-placehydrocarbon reserves in the country. In fact, six out of seven producing basins in India have been discovered by ONGC. ONGC produces morethan 1.27 million Barrels of Oil Equivalent (BOE) per day. It alsocontributes over three million tonnes per annum of Value-Added-Products including LPG, C2 - C3, Naphtha, MS, HSD, Aviation Fuel,SKO etc.

VISION & MISSION

To be global leader in integrated energy business through

sustainable growth, knowledge excellence and exemplary

governance practices. World Class

Dedicated to excellence by leveraging competitive advantages inR&D and technology with involved people.

Imbibe high standards of business ethics and organizational values.

Abiding commitment to safety, health and environment to enrichquality of community life.

Foster a culture of trust, openness and mutual concern to makeworking a stimulating and challenging experience for our people.

Strive for customer delight through quality products and services.

Integrated In Energy Business

Focus on domestic and international oil and gas exploration and

production business opportunities.

Provide value linkages in other sectors of energy business.

Create growth opportunities and maximize shareholder value.

Dominant Indian Leadership

Retain dominant position in Indian petroleum sector and enhanceIndia's energy availability.




ONGC WSS

MORE OIL “WSS” Introduction:

In well production stage if the well gets depleted by any reason, itresults in low pressure of formation conditions of that well. Thus WSSmethods are used for enhancement of productivity of the well. TheWSS technique to be applied depends on reservoir history andformation characteristics.

SERVICES OFFERED:There are different services which we can include in WSS are

Hydraulic Fracture, Acid Treatment, Sand Control, Nitrogen Injectionand Coiled Tubing Unit.




Hydraulic Fracturing:A tube of smaller diameter like 1¼”, 1½” has been inserted into the

drilled well for stimulation. We make a special gel and slurry whichcan be inserted into the well to open the chocked production casing.Depending on pressure, temperature and depth we should make thesethings. By inserting the gel into the cracks we remove the blockage andhence create a path to let the hydrocarbon flow. Aft.er it we remove gelfrom the production pipe and again we got the normal production orProduction of hydrocarbon fluid with some reduced pressure.

Acid Treatment:

When damage in formation occurs we do Acid Treatment for removethe damaged part and its used for deeper where the well bore is awayfrom the formation region. We pressurized the annuals and then acid is pumped into the well and this way we can open the production path forthe hydrocarbon fluid.

Sand Control:When in unconsolidated part the sand collapse occur sand controlmethods uses to protect the wall and hence we can isolate the system.

Nitrogen Injection:In Nitrogen Injection is we convert the liquid nitrogen into hot nitrogengas and inject into the well so that blockage of sand and other particleshas been removed and the clear path is made to flow the hydrocarbonfluid.

CTU (Coiled Tubing Unit):

It’s a two tubing operation for removal of sand from the Formation.Used to avoid installation of a particular rig for particular well. Process

carried out by lowering coiled tube inside production tubing and clearobstruction that reduces flow. Also known as foam treatment.

Hot oil circulation:Hot oil with temp around 82 degree centigrade is circulated through thewell to clear wax and sand formations from the tubing.




MAINTENANCE

What is maintenance and why is it performed?

Past and current maintenance practices in both the private and

government sectors would imply that maintenance is the actions

associated with equipment repair after it is broken. The dictionary

defines maintenance as follows: “the work of keeping something in

proper condition; upkeep.” This would imply that maintenance should

be actions taken to prevent a device or component from failing or to

repair normal equipment degradation experienced with the operation of

the device to keep it in proper working order. Unfortunately, data

obtained in many studies over the past decade indicates that most

private and government facilities do not expend the necessary resources

to maintain equipment in proper working order. Rather, they wait for

equipment failure to occur and then take whatever actions are necessary

to repair or replace the equipment. Nothing lasts forever and all

equipment has associated with it some predefined life expectancy oroperational life. For example, equipment may be designed to operate at




full design load for 5,000 hours and may be designed to go through

15,000 start and stop cycles.

Types of Maintenance

1. Breakdown maintenance

It means that people waits until equipment fails and repair it. Such a

thing could be used when the equipment failure does not significantly

affect the operation or production or generate any significant loss other

than repair cost.

2. Preventive maintenance

It is a daily maintenance (cleaning, inspection, oiling and re-

tightening), design to retain the healthy condition of equipment and

prevent failure through the prevention of deterioration, periodic

inspection or equipment condition diagnosis, to measure deterioration.

It is further divided into periodic maintenance and predictive

maintenance. Just like human life is extended by preventive medicine,

the equipment service life can be prolonged by doing preventive

maintenance.

2a. Periodic maintenance (Time based maintenance - TBM)

Time based maintenance consists of periodically inspecting, servicing

and cleaning equipment and replacing parts to prevent sudden failure

and process problems.

2b. Predictive maintenance

This is a method in which the service life of important part is predicted based on inspection or diagnosis, in order to use the parts to the limit

of their service life. Compared to periodic maintenance, predictive

maintenance is condition based maintenance. It manages trend values,

by measuring and analyzing data about deterioration and employs a

surveillance system, designed to monitor conditions through an on-line

system.




3. Corrective maintenance

It improves equipment and its components so that preventive

maintenance can be carried out reliably. Equipment with design

weakness must be redesigned to improve reliability or improvingmaintainability

4. Maintenance prevention

It indicates the design of a new equipment. Weakness of current

machines are sufficiently studied (on site information leading to failure

prevention, easier maintenance and prevents of defects, safety and easeof manufacturing) and are incorporated before commissioning a new

equipment.

List of truck maintained at WSS Ahmedabad

Saij base:-

S.no Vehicle type Vehicle registration no.

1. LN2 Pumper 1.GJ-1-R 15402.GJ-18-A 850

2. Acid pumper 1.GJ-18-H 75492.GJ-18-H 77113.GJ-1-R 1426

Frac pumper 1.GJ-1-R-13812.GJ-18-A-7653

3. Send blender 1.GJ-1-BK-8072

2.GJ-18-H-9007

4. Sand dumper 1.GJ-1XX-49722.GJ-1-U-51433.GJ-18-H-7695

5. Coil Tubing Unit(CTU) 1.GJ-1R-1139




Description of above mentioned vehicle:-

LN2 Pumper :-

LN2 pumper carries a cryovessel at back side and a pump on chassis it

carries liquid nitrogen which is used for stimulation purpose which will

be discussed later on nitrogen section.

Acid pumper:-

Acid pumper is used for acid job for pumping acid into the well for

stimulation purposes an Acid pumper carries two tankers on chassis

along with a triplex pump behind the tankers. Two of the tankers carries




HCl and HF respectively actual function of Acid pumper will be

discussed in Acid job section.

Sand blender:-

Sand blender is used for blending of sand during hydraulic fracturing

at job side, sand flows upwards through two conveyer located at back

side of blender after that sand is added with additives like gel and

chemicals.

Coil Tubing Unit (CTU):-

CTU is used to forcefully pump the additives/chemicals into the well

when it is normally not injecting effectively into well due to action of

gravity.




Multipurpose pumping unit :-

Multipurpose pumping unit is used for pumping purposes generally

during Gravel packing and sand control operations. The main function

of unit will be discussed later on gravel pack section.

BASICS OF AUTOMOBILE ENGINEERINGGENERAL LAYOUT OF AN AUTOBOBI LE:-

Main components of a basic automobile:-

Engine – An engine is a machine designed to convert energy into

useful mechanical motion. Heat engines, including internal

combustion engines and external combustion engines (such as steamengines) burn a fuel to create heat, which then creates motion.




Flywheel:- flywheel is a rotating mechanical device that is used to

store rotational energy. Flywheels have a significant moment of

inertia and thus resist changes in rotational speed. The amount of

energy stored in a flywheel is proportional to the square of itsrotational speed. Energy is transferred to a flywheel by applying

torque to it, thereby increasing its rotational speed, and hence its

stored energy. Conversely, a flywheel releases stored energy by

applying torque to a mechanical load, thereby decreasing its rotational

speed.

Common uses of a flywheel includeProviding continuous

energy when the energy source is discontinuous. For example,flywheels are used in reciprocating engines because the energy

source, torque from the engine, is intermittent.

Delivering energy at rates beyond the ability of a continuous

energy source. This is achieved by collecting energy in the

flywheel over time and then releasing the energy quickly, at

rates that exceed the abilities of the energy source.

Controlling the orientation of a mechanical system. In suchapplications, the angular momentum of a flywheel is purposely

transferred to a load when energy is transferred to or from the

flywheel.

Clutch:- A clutch is a mechanical device that engages and

disengages the power transmission, especially from driving shaft to

driven shaft. Clutches are used whenever the transmission of power

or motion must be controlled either in amount or over time

Gear box:- A machine consists of a power source and a power

transmission system, which provides controlled application of the

power. The most common use is in motor vehicles, where the

transmission adapts the output of the internal combustion engine to

the drive wheels. Such engines need to operate at a relatively high

rotational speed, which is inappropriate for starting, stopping, and




slower travel. The transmission reduces the higher engine speed to

the slower wheel speed, increasing torque in the process.

Differential :- Differential gear, in automotive mechanics, gear

arrangement that permits power from the engine to be transmittedto a pair of driving wheels, dividing the force equally between

them but permitting them to follow paths of different lengths, as

when turning a corner or traversing an uneven road. On a straight

road the wheels rotate at the same speed; when turning a corner the

outside wheel has farther to go and will turn faster than the inner

wheel if unrestrained.

Brake:-A brake is a mechanical device which inhibits motion

Types of braking system:-

Disc Brake

Drum Brake

Single-Circuit Hydraulic Brake

Dual-Circuit Hydraulic Brake

Brake-by-wire Antilock Braking System (ABS)

Power Brake Booster

Air Brakes

Advanced Emergency Braking System (AEBS)

TYPES OF ENGINE :-

http://en.wikipedia.org/wiki/Machine







Main mechanism used to transfer power from one part to another

part:-

Propeller shaft

Belt drive

Pneumatic system(uses air)

Hydraulic system(uses liquid generally oil)

Main components of Kenworth truck

used at WSS Saij base:-

Some of the basic component we discussed earlier now we will

discuss those component which plays vital role to help in various

application for oil and natural gas production

PUMPS:- These pumps are frequently used in Kenworth trucks

which is used at WSS Ahmedabad for Oil and Natural Gas production

1. Centrifugal Pump: - A centrifugal pump converts the input

power to kinetic energy in the liquid by accelerating the liquid by

a revolving device (centrifugal action) - an impeller. The most

common type is the volute pump. Fluid enters the pump through

the eye of the impeller which rotates at high speed. The fluid is

accelerated radially outward from the pump chasing. A vacuum

is created at the impellers eye that continuously draws more fluid

into the pump.

Principle –“An increase in the fluid pressure from the pump inlet to its

outlet is created when the pump is in operation. This pressure difference

drives the fluid through the system or plant. The centrifugal pump

creates an increase in pressure by transferring mechanical energy from

the motor to the fluid through the rotating impeller. The fluid flows

from the inlet to the impeller centre and out along its blades. The

centrifugal force hereby increases the fluid velocity and consequently

also the kinetic energy is transformed to pressure.”




Types of impeller:-

Open

Semi Open

Closed or Shrouded

2.

Triplex pump:- It is mounted on back side of an Acid pumper having three cylinders. A triplex pump is a reciprocating piston/plunger device designed to circulate drilling fluid underhigh pressure (up to 7,500 psi (52,000 kPa) ) down the drillstring and back up the annulus. Triplex pump is a largereciprocating pump used to circulate the acid on a well. It is animportant part of the oil well drilling equipment.

3. PT pump :- Pressure timming pump sucks the fuel from the

fuel tank through filters and water separator. After that itdelivers the fuel to a common rail from where the fuel goes intothe injectors.The pump also governs the speed of the engine bycontrolling the throttle shaft position which in turn controls theamount of fuel going into the injectors.

Figure 1 Casing of centrifugal pump Figure2 Impeller of centrifugal pump




Air Compressor: - An air compressor is a device that converts

power (usually from an electric motor, a diesel engine or a gasoline

engine) into kinetic energy by compressing and pressurizing air, which,

on command, can be released in quick bursts. In Kenworth truck usedat WSS Saij base shaft of compressor is mounted with shaft coming out

from PT pump

After compression temperature of air rises and need to be cool, for this

purpose we use an after cooler. Compressed air used for various

purposes main use of compressed air in “BRAKING SYSTEM”.

Transmissions :-

A machine consists of a power source and a power transmission system,

which provides controlled application of the power.

OR

Assembly of parts including the speed-changing gears and the propeller

shaft by which the power is transmitted from an engine to a live axle.

Type of transmission mainly used at WSS Ahmedabad:-

Manual transmission-A manual transmission, also known as a

manual gearbox, stick shift (for vehicles with hand-lever shifters),

standard transmission, 4/5/6 speed (depending on gears) or

simply a manual, is type of transmission used in motor vehicle

applications. It uses a driver-operated clutch engaged and

1 . Single acting single cylinder

compressor

http://en.wikipedia.org/wiki/Machine_(mechanical)

http://en.wikipedia.org/wiki/Machine_(mechanical)




disengaged by a foot pedal (automobile) or hand lever

(motorcycle), for regulating torque transfer from the engine to the

transmission; and a gear selector operated by hand

Automated manual transmission - An automated manualtransmission (AMT) combines a traditional clutch actuated

manual gearbox with a computer-controlled shift actuator and

clutch. The best shift patterns are selected electronically to

provide optimal power or fuel efficiency. An AMT is a proven

technology used around the world. At Detroit, we believe it

represents the next generation. With computer-controlled shifting

and clutch engagement, only two pedals are needed to operate thetruck, brake and accelerator.

Allison transmission – Alison transmission is a kind of

automatic transmission used in Kenworth truck used at WSS

Ahmedabad it has various series but Kenworth vehicle uses 9000

series transmission. An automatic transmission (also called

automatic gearbox) is a type of motor vehicle transmission that

can automatically change gear ratios as the vehicle moves, freeingthe driver from having to shift gears manually. Most automatic

transmissions have a defined set of gear ranges, often with a

parking pawl feature that locks the output shaft of the




transmission stroke face to keep the vehicle from rolling either

forward or backward. Similar but larger devices are also used for

heavy-duty commercial and industrial vehicles and equipment.

Some machines with limited speed ranges or fixed engine speeds,such as some forklifts and lawn mowers, only use a torque

converter to provide a variable gearing of the engine to the

wheels.

Hydraulic motor:- Symbol

A hydraulic motor is a mechanical actuator that converts hydraulic

pressure and flow into torque and angular displacement (rotation). The

hydraulic motor is the rotary counterpart of the hydraulic cylinder.

Hydraulic motors are used for many applications now such as winches

and crane drives, wheel motors for military vehicles, self-driven cranes,

and excavators. Conveyor and feeder drives, mixer and agitator drives,

roll mills, drum drives for digesters, trommels and kilns, shredders for

cars, tyres, cable and general garbage, drilling rigs, trench cutters, high- powered lawn trimmers, plastic injection machines.

Types of engine used in Kenworth truck at WSS

Ahmedabad Saij base:-

6 cylinder inline (L6) - The straight-six engine or inline-six

engine (often abbreviated I6 or L6) is an internal combustion




engine with the cylinders mounted in a straight line along the

crankcase with all the pistons driving a common crankshaft

(straight engine).

The bank of cylinders may be oriented at any angle, and wherethe bank is inclined to the vertical, the engine is sometimes called

a slant-six. The straight-six layout is the simplest engine layout

that possesses both primary and secondary mechanical engine

balance, resulting in much less vibration than engines with fewer

cylinders

12 cylinder v shaped (V12) :-

MAINTENANCE OF TRUCKS USED AT WSS BASE

Every truck purchased from Kenworth should come with maintenance

manuals. These are a vital accessory and should be kept in a safe place

and be readily available. They contain valuable information on topics

such as determining scheduled maintenance intervals, lubrication and

2 :- V12 CUMMINS ENGINE AT WSS SAIJ BASE




fluid level checks, noise emission controls maintenance, and torque

specification.

A preventive maintenance (PM) schedule should be based on the

distance you drive or hours you operated the vehicle during the job,along with wear and tear on your truck. To determine the correct

maintenance schedule for your vehicle you must first define the

conditions you drive in and how you drive. If you run 80 mph you will

have higher maintenance costs than if you run 65 mph. If you haul

heavy loads through mountains, the wear and tear on your truck is

obviously greater. Most maintenance manuals have a list of schedules

from which you can identify the one that is best designed for your

situation.

Truck Tire Air Pressure

When conscientiously followed, the PM can anticipate, identify and

solve potential problems that can harm your truck and business.

Procedures can be as simple as checking the engine oil and tire air

pressure frequently, or more sophisticated, such as using engine oil

analysis to extend the drain intervals. Most owner-operators performsome maintenance activity. As you gain experience, you will become

more capable of performing tasks yourself.

A simple plan that doesn't require technical skill and special equipment

will include tires, engine oil, wipers, lights, filters, coolant and

belts/hoses. A more technical PM will include brakes, drive axles,

wheel seals, transmission, batteries, exhaust, driveline, suspension,

steering, clutch and engine.Every good PM schedule begins with establishing a maintenance

escrow savings account. The industry standard for maintenance escrow

savings is based on a time-proven formula.




HYDRAULIC FRACTURING

What Is Hydraulic Fracturing?

Hydraulic fracturing is a process used in nine out of 10 oil and naturalgas wells all over the world, where millions of gallons of water, sandand chemicals are pumped underground to break apart the rock andrelease the gas.

Why fracture?

Hydraulic fracture operations may be performed on a well for one (or

more) of three reasons:

• To bypass near -wellbore damage and return a well to its “natural” productivity

• To extend a conductive path deep into a formation and thus increase productivity beyond the natural level

• To alter fluid flow in the formation.

Hydraulic fracturing is a Well-stimulation technique that is mostsuitable to wells in low and moderate-permeability reservoirs that donot




provide commercial production rates even tough formation damagesare removed by acidizing treatments. Hydraulic fracturing jobs arecarried out at well sites using heavy equipment blenders, fluid tanksand proppant tanks.

A hydraulic fracturing job can be divided into two stages:

(a). The pad stage, and (b). The slurry stage.

In the pad stage fracturing fluid only is injected into the well to breakdown the formation and create a pad. The pad is created because thefracturing fluid injection rate is higher than the flow rate which the fluid

can escape into the formation. Aft.er the pad grows to a desirable size,the slurry stage is started. During the slurry stage, the fracturing fluidis mixed with sand/proppant in a blender and the mixture is injectedinto the pad/fracture. Aft.er filling the fracture with sand/proppant, thefracturing job is over and the pump is shut down. Also, to prop thefracture the sand/proppant should have a compressive strength that ishigh enough to resist the stress from the formation.

Fluid and proppant selectionThe major considerations for fluid selection are usually viscosity (forwidth, proppant transport or fluid-loss control) and cleanliness (aft.erflow back) to produce maximum post fracture conductivity.Other considerations that may be major for particular cases include• Compatibility with reservoir fluids and reservoir rock • Compatibility with reservoir pressure (e.g., foams to aid flow backin low-pressure reservoirs)• Surface pump pressure or pipe friction considerations • Cost • Compatibility with other materials (e.g., resin coated Proppant)• Safety and environmental concerns

Method

A hydraulic fracture is formed by pumping the fracturing fluid into the

wellbore at a rate sufficient to increase pressure downhole at the targetzone (determined by the location of the well casing perforations) to




exceed that of the fracture gradient (pressure gradient) of the rock. Thefracture gradient is defined as the pressure increase per unit of the depthdue to its density and it is usually measured in pounds per square inch per foot or bars per metre. The rock cracks and the fracture fluidcontinues further into the rock, extending the crack still further, and soon. Fractures are localized because of pressure drop off with frictionalloss, which is attributed to the distance from the well. Operatorstypically try to maintain "fracture width", or slow its decline, followingtreatment by introducing into the injected fluid a proppant – a materialsuch as grains of sand, ceramic, or other particulates that prevent thefractures from closing when the injection is stopped and the pressure ofthe fluid is removed. Consideration of proppant strengths and

prevention of proppant failure becomes more important at greaterdepths where pressure and stresses on fractures are higher. The proppedfracture is permeable enough to allow the flow of formation fluids tothe well. Formation fluids include gas, oil, salt water and fluidsintroduced to the formation during completion of the well duringfracturing. During the process, fracturing fluid leak off (loss offracturing fluid from the fracture channel into the surrounding permeable rock) occurs. If not controlled properly, it can exceed 70%

of the injected volume. This may result in formation matrix damage,adverse formation fluid interactions, or altered fracture geometry andthereby decreased production efficiency. The location of one or morefractures along the length of the borehole is strictly controlled byvarious methods that create or seal off holes in the side of the wellbore.Hydraulic fracturing is performed in cased wellbores and the zones to be fractured are accessed by perforating the casing at those locations.

Hydraulic-fracturing equipment used in oil and natural gas fieldsusually consists of a slurry blender, one or more high-pressure, high-volume fracturing pumps (typically powerful triplex or quintuplex pumps) and a monitoring unit. Associated equipment includesfracturing tanks, one or more units for storage and handling of proppant, high-pressure treating iron, a chemical additive unit (used toaccurately monitor chemical addition), low-pressure flexible hoses, andmany gauges and meters for flow rate, fluid density, and treating

pressure. Chemical additives are typically 0.5% percent of the totalfluid volume. Fracturing equipment operates over a range of pressures




and injection rates, and can reach up to 100 mega pascals (15,000 psi)and 265 litres per second (9.4 cu ft../s) (100 barrels per minute).

Hydraulic Fracturing Process

Hydraulic fracturing happens in small sections called stages. It starts atthe end of the wellbore and moves toward the beginning.

Step 1 – Perforating the Casing

First, a perforating gun is lowered into a targeted position within thehorizontal portion of the well. Then, an electrical current is sent down

the well to set off a small explosive charge. This shoots tiny holesthrough the well casing and out a short, controlled distance into theshale formation. The holes created by the “perf” gun serve two

purposes: they provide access for the fracturing fluid to enter theformation and subsequently allows natural gas to enter the wellbore.

Step 2 – Shale Fracturing

The fracturing of a well creates a complex network of cracks in the

shale formation. This is achieved by pumping water, sand and a smallamount of additives down the wellbore under high pressure. Aft.erthese cracks are created the sand will remain in the formation proppingopen the shale to create a pathway for the gas to enter the wellbore andflow up the well.

Step 3 – Repeat in Stages

During each stage experts will monitor, adjust and record all of thestage parameters to ensure worker and public safety and to maximizethe natural gas production from the shale. Aft.er each stage iscompleted, a plug will be set and new perforations created to direct thefrac fluid to the next stage. By segmenting the well in stages, a greateramount of gas is produced from the lateral length of the well.




Acid job

What is an Acid job?

Acid jobs have been applied to wells in oil and gas bearing rock

formations for many years. Acidizing is probably the most widely used

workover and stimulation practice in the oil industry .

By dissolving acid soluble components within underground rock

formations, or removing material at the wellbore face, the rate of flow

of oil or gas out of production wells or the rate of flow of oil-displacing

fluids into injection wells may be increased.A number of different acids are used in conventional acidizing

treatments, but in ONGC we mainly use these two acids:

Hydrochloric, HCl and Hydrofluoric, HF




Types of Acidization:-

SANDSTONE ACIDIZATION

The descriptor\sandstone is derived from the geologic classification of

rocks with high quartz silica content. Besides the obvious quartz

component, they contain other minerals such as aluminosilicates,

metallic oxides, sulfates, chlorides, carbonates and non-crystalline

(amorphous) siliceous material. The minerals deposited in the original

sediment are called detrital species. Most have a high degree of

associated water. As fluids are produced through the matrix of the rock,

the drag forces can move some of these minerals, clogging the pore

throats. Various well operations can result in formation damage. Forexample, drilling mud and completion fluid usually penetrate sandstone

formations. This invasion of filtrate can introduce an entirely different

chemical environment, which the acid treatment must address.

Additional formation damage may occur during perforating, gravel

packing, and normal production or injection operations. Acid dissolves

a variety of damaging materials along with most formation minerals.

An understanding of the chemistry is basic to the selection of acid typeand concentration.

Matrix Acidization

Matrix acidization is a technique in which a solvent is injected into the

formation to dissolve some of the materials present and hence recover

or increase the permeability in the near-wellbore region. Such

treatments are called ―matrix‖ treatments because the solvent is

injected at pressures below the parting pressure of the formation so thatfractures are not created. The objective is to greatly enhance or recover

the permeability near the wellbore, rather than affect a large portion of

the reservoir. The most common acids are hydrochloric acid (HCl),

used primarily to dissolve carbonate minerals, and mixtures of HCl and

hydrofluoric acid (HF), and also used to attack silicate minerals such

as clays and feldspars. Other acids, particularly some weak organic

acids, are used in special applications, such as high-temperature wells.

Matrix acidizing is a near-wellbore treatment, with all the acid reacting




within about 1 ft. of the wellbore in sandstone formations and within a

few inches to perhaps as much as 10 ft. from the wellbore in carbonates.

In considering the many aspects of the matrix acidizing process, the

focus is on the key design variables; to be useful, any model of the process must aid in optimizing the design. The primary design

considerations are

Fluid selection — acid type, concentration and volume

Injection schedule — planned rate schedule and sequence of injected

fluids acid

Coverage and diversion — special steps taken to improve acid contactwith the formation

Real-time monitoring — methods to evaluate the acidizing process as it

occurs

Additives — other chemicals included in the acid solution to enhance the

process or to protect tubular goods.

Sandstone acidizing success requires a significantly better

understanding of chemistry than does carbonate acidizing. Because the

formation and the damage can have complicated crystalline structures

that can yield a variety of reaction products,. If carefully executed, 75%

of well-engineered sandstone acid treatments should be successful,

resulting in significant production enhancement.

Acidization Steps

Preflush: Preflush with• 5% to 15% HCl

• Acetic acid

The preflush displaces formation brine away from the wellbore to

prevent it from mixing with reacted mud acid and causing a damaging

precipitate. If the formation contains more than 1% to 2% carbonate,

an HCl preflush is necessary to dissolve the carbonate, prevent the

waste of mud acid and prevent formation of the insoluble precipitate




CaF2. If completion brines such as seawater, potassium chloride (KCl),

calcium chloride (CaCl2) or calcium bromide (CaBr) have been used

in the well prior to acidizing, the brines will mix with the mud acid in

the formation. Preflushing the mud acid with HCl or brine containingammonium chloride to dilute the brines and remove them away from

the wellbore helps avoid this problem. Preflushes can also be used to

displace and isolate incompatible formation fluids (either brine or crude

oil).

Main fluid stage: The HCl-HF mixture used in each treatment. It is

demonstrated that low HF concentrations should be used to avoid the

precipitation of AlF3 or CaF2 if the remaining calcite cannot be

quantified. It is also suggested that 12% HCl – 3% HF can be used even

in low-calcite environments without a precipitation problem. Some

significant problems that may occur in high-clay-content formations

include compromised formation integrity and excessive fines

generation. These conditions can be the result of too high HF

concentrations.

Volume: Gidley (1985) reported that for the most successful mud acid

treatment, more than 125 gal/ft.. of mud acid is required. Less may be

used where only shallow damage exists around new perforations (e.g.,

25 to 75gal/ft. is used to remove mud damage or in a spearhead

treatment as an acid to perforation breakdown prior to hydraulic

fracturing). When the damage is quantified, a simulator can be used to

optimize the volumes of mud acid mixtures to be used. Simulators can

be used to aid the modification of volumes if several job stages are

used.

Concentration: Regular mud acid (12% HCl – 3% HF) is the normal

concentration to use to remove damage in clean quartzose sands. Field

experience has shown that weaker concentrations (0.5% to 1.5% HF)

can be effective for other sands. Mineral composition from a laboratory

analysis can also dictate when less than 3% HF should be used. If the

combined percentage of clay and feldspar is more than 30%, 1.5% HF

or less should be used. Field experience with some tight sandstones has




shown that concentrations as low as 0.6% HF may be used (e.g., the

Morrow formation in Texas and New Mexico). If the appropriate

concentration is in doubt, an acid response test on a typical core should

be performed if a core sample is available.Over flush stage: The over flush is an important part of a successful

sandstone acidizing treatment. An over flush has several purposes:

• To displace non reacted mud acid into the formation

• To displace mud acid reaction products away from the wellbore

• To remove oil-wet relative permeability problems caused by

some corrosion inhibitors.When over flushing the acid treatment, it is important to remember that

miscible fluids are required to perform these listed functions. Aqueous-

base liquids should therefore be considered as the first displacing and

flushing fluid. Another fluid system can then be used for addressing the

other concerns as the conditions dictate. This suggests that multiple

fluid types should be used as over flush stages for a given set of

circumstances. Typical over flushes for mud acid treatments are• Water containing 3% to 8% ammonium chloride

• Weak acid (3% to 10% HCl)

• Diesel oil (oil wells only and only following a water or weak acid

over flush)

• Nitrogen (gas wells only and only following a water or weak acid

over flush).Recent experience indicates the advantage of including HCl or acetic

acid in the first part of the over flush to maintain a low-pH environment

for the displaced spent mud acid stage. As the hydrogen ions adsorb on

non-reacted clay deeper in the formation, the pH rises unless it is

replaced by fresh acid in the first part of the over flush. Although the

most economic over flush of a mud acid treatment is water containing

3% to 8% ammonium chloride with 10% ethylene glycol monobutylether (EGMBE) and a polyquarternary amine clay stabilizer, it does not




address the pH problem without acetic acid addition. Also, certain

chemicals can be added to acids to prevent or reduce the precipitation

of some compounds (e.g., iron complexing agents, sulfate scale

inhibitors and anti-sludge agents). An example of the role of reservoirmineralogy was presented by Boyer and Wu (1983) in evaluating acid

treatments in the Kuparuk River formation in Alaska. Their results

indicate that fluoboric acid significantly reduces the amount of

hydrated silica formed in comparison with conventional HCl-HF

systems.




GRAVEL PACK

Gravel packing consists of installing a downhole filter in the well to

control the entry of formation material but allow the production ofreservoir fluids. The gravel-packed completion is perhaps the most

difficult and complex routine completion operation because it consists

of many interrelated completion practices.

Marine deposited sands, most oil and gas reservoir sands, are often

cemented with calcareous or siliceous minerals and may be strongly

consolidated. In contrast, Miocene or younger sands are often

unconsolidated or only partially consolidated with soft. Clay or silt

and are structurally weak. These weak formations may not restrain

grain movement, and produce sand along with the fluids especially athigh rates.




Objective in gravel packing

There are two primary objectives for gravel packing a well.

1. The annulus between the screen and casing must be packed withgravel. Filling the annulus with properly-sized gravel ensures that the

formation sand is not produced to the surface.

2. Pack each perforation with gravel. Filling the perforations with

gravel is the key to obtaining high productivity. In an unconsolidated

formation, any perforation that is unfilled with gravel will fill with

formation sand and severely restrict productivity from such

perforations.

The following discussion deals with filling the annulus. Prepacking

perforations with gravel discusses perforation packing. The crossover

circulating technique is the most common method used to place thegravel around the screen. The gravel-pack equipment and service tools

allow circulating the gravel down the work string above the packer and

into the screen/casing annulus below the packer. The returns flow up

the wash pipe and cross over into the work string/casing annulus. The

fluid used to transport the gravel can either leak off to the formation or

be circulated or reversed out of the hole through the wash pipe,

depending on the position of the service tools.




Advantages of open hole gravel packs:-

1. Low drawdown and high productivity

2. Excellent longevity

3. No casing or perforating expense

Disadvantages of open hole gravel packs:-

1. Sometimes difficult to exclude undesirable fluids such as water

and/or gas

2. Not easily performed in shale the erode or slough when brine is

pumped past them.3. Requires special fluids for drilling the open hole section

Guidelines for selecting open hole-gravel pack candidates:-

1. Formations where cased hole gravel packing has unacceptable

productivity.

2. Situations where increased productivity is required.

3. Reservoirs where long, sustained single phase hydrocarbon flow

is anticipated.

4. Situations where work over’s for isolating gas or water cannot be

accomplished.

5. Wells where high water-oil or gas oil ratios can be tolerated

6. Reservoirs with single uniform sands (avoid multiple sands

interspersed with troublesome shale layers or water sands)

7. Formations that can be drilled and maintaining borehole stability

in the completion interval

8. Situations where cased hole completions are significantly more

expensive (Horizontal wells)




Selection criteria for gravel packing

For better results selection of the gravel and screen plays major role

here is a brief discussion on the selection criteria. Design the gravel

Pack includes

1. Gravel size

2. Completion type

3. Screen size

4. Transportation of the gravel

The specifications define minimum acceptable standards for the sizeand shape of the grains, the amount of fines and impurities, acid

solubility, and crush resistance. Only a few naturally occurring sands

are capable of meeting the API specifications without excessive

processing. These sands are characterized by their high quartz content

and consistency in grain size.

Advantages of gravel packing :-

1. It offers economical methods of sand control.

2. Gravel packing covers long interval up to 500 fts.

Disadvantages of gravel packing:-

1. While initial installation is economical, a remedial treatment to

replace a failed screen may involve an expensive fishing job

2. Cause pressure drop

Job Description :-

• Gravel Packing

1. First of all the tubing of the well was removed with the help of a

rig and a surge tool for back surging along with R3 packer is

lowered in the well.

2. The packer is set above the perforations and annulus is filled with

brine and BOP is closed, due to which further pressure is




increased so that flapper valve opens and a suction is created

below the packers and oil is forced out of the perforations with

sand mixed with it.

3.

After that surge tool is pulled out and a sharp edged tube isinserted. A gel solution is pumped into the well to clean the sand

and other dirt present in the well.

4. After cleaning the well, pipe is pulled out and Bottom Hole GP

Assembly is lowered consisting of a screen at it’s bottom, Bull

Plug, Landing Nipples, Cross-over tool and Gravel Exit Port.

5. A pre-made Gel-Gravel slurry is pumped through the assembly

and a proper pack is achieved by pressurising the slurry a no. oftimes. Preserve tool is kept to allow incomplete slurry

dehydration. The excess slurry is pumped out to pull out the

Cross-over tool.

6. Finally a Leg tool with a Kelly tool is lowered in the well and

stabbed on the Landing Nipple expanding leg in the process for

sealing off the annulus.

Return:-Water, Sand, Brine solution, Excess Gel-Slurry mixture and

other additives used in the process.

Result/Remarks:-As the pressure is increased in the well the Gravel

Packing job was confirmed.

Conclusion:-As 2nd Generation Workover techniques, Coil tubing

operations are called out for well servicing without the need to subdue

the well. It is quick, efficient and cost effective.




COIL TUBIG UNIT (CTU)

Introduction to Coiled Tubing Unit (CTU)

Coiled Tubing (CT) has been defined as any continuously-milled

tubular product manufactured in lengths that require spooling onto a

take-up reel, during the primary milling or manufacturing process. The

tube is nominally straightened prior to being inserted into the wellbore

and is recoiled for spooling back onto the reel. Tubing diameter

normally ranges from 0.75 in. to 4 in., and single reel tubing lengths in

excess of 30,000 ft.. have been commercially manufactured. Common

CT steels have yield strengths ranging from 55,000 PSI to 120,000 PSI.

Key Elements of a CT Unit:-

The coiled tubing unit is comprised of the complete set of equipment

necessary to perform standard continuous-length tubing operations in

the field. The unit consists of four basic elements:-

• Coiled Tubing

• Tubing reel

• Injector

•

Stuffing box & stripper rubber

• Blow out preventer (BOP)

• Control cabin




Coiled Tubing (CT):-It is the main component of a CTU. The details

regarding coiled tubing are covered under the following headings.

CT Manufacturing

CT Mechanical Performance

CT String Design

1. CT Manufacturing:-The material used for manufacturing CT is usually

a carbon-steel alloy. Two major companies involved in the

manufacturing are Quality Tubing Inc. (QTI) and Precision Tube

Technology (PTT). The tubing is first manufactured as sheet steel. The

strip's thickness establishes the CT wall thickness and the strip's width

determines the OD of the finished CT.

2.

CT Mechanical Performance:-Unlike other tubular products, CT is

plastically deformed with normal use which imparts fatigue on the CT

string. Plastic deformation can be described as deformation that

remains aft.er the load causing it is removed. Fatigue can be defined

as failure under a repeated or otherwise varying load, which never

reaches a level sufficient to cause failure in a single application.




3. CT String Design:-The simplest method of designing a CT string

considers only the wall thickness necessary at a given location for the

required mechanical strength and the total weight of the string. In thismethod only the buoyancy is assumed to be acting on the CT where it

is open-ended and hanging vertically in a fluid.A properly sized CT

string must have the following attributes for the planned operation:

Enough mechanical strength to safely withstand the combination of

forces imposed by the job

Adequate stiffness to RIH to the required depth and/or push with the

required force

Light weight to reduce logistics problems and total cost

Maximum possible working life




1. Tubing Reel:-It houses the CT and helps in transporting it. Flexible

coiled tubing can be wound over it from which the tubing can be

inserted and removed much quicker than tubing installed from rigid

pipe segments.

2. Injector:-It provides the surface drive force to run and retrieve the CT.

The following is a picture of the injector and below is its schematic.

3. Stuffing box & stripper rubber:-The stripper is located between the

BOP and the injector head. It is sometimes referred to as a pack off or

stuffing box and provides the primary operational seal between

pressurized wellbore fluids and the surface environment. The stripper

provides a dynamic seal around the CT during tripping and a static seal

around the CT when there is no movement. The latest style of stripper

devices is designed with a side door that permits easy access and

replacement of the sealing elements, with the CT in place.




ADVANTAGES OF CTU:-

1. CTU operations are cost and time saving

2.

CTU operations can be performed under pressure.

3. No need for killing the well – no formation damage.

4. Fast RIH and POOH (speed can go upto 250 ft./min).

5. It is the only method for wells completed with packers.

6. Can perform logging and perforation operations for highly deviated wells.

7. Drilling can also be performed with CTU.

Disadvantages/limitations of CTU:-

1. Yield strength of CT is comparatively low.

2. Maximum pumping pressure is limited in CTU (commonly 5000-7000 psi).

3. Can contain well head pressures only upto 2500 psi.

4. CT string cannot be rotated.

CTU Operations:-

The global oil and gas industry is using coiled tubing for an ever-

increasing array of well intervention projects. Coiled tubing has now

been regarded as second generation work over system and offers a

number of operational and economic advantages, including: live well

intervention, elimination of well kill and potentially damaging heavy-




weight kill fluids, reduced operational footprint, horizontal

intervention, and the ability to intervene without a rig. These

advantages have led to the development of truly fit-for-purpose coiled

tubing systems.

There are numerous areas where coiled tubing can offer a highly

effective and cost efficient alternative. Few of them are:

1. Well Cleaning

2.

Fishing and Milling

3. Fluid knockout (Activation)

4. Stimulation (Fracturing/Acidizing)

5. Cementing operation

6. Drilling Applications

7.

Velocity string8. Zone Isolation

9. Sand Control Completions.

10. Setting a plug or packer

11. Sidetracking and Re-entry

12. Removal of scales & wax, etc.

Important applications of CTU:-

1. Well Cleaning:-Well cleaning is the most common operation

performed through a CTU. During the course of its life, accumulation

of solids occurs inside the well bore. Materials such as formation sand




or fines, proppant flow back or fracture operation screen out, and

gravel-pack failures are the common fills. These materials will act to

impede fluid flow and hence, affect the productivity or injectivity of

the well. The accumulation therefore needs to be cleared. This

operation, popularly known as bottom cleaning, is also called as sand

washing, sand jetting, sand cleanout, and fill removal. The procedure

includes lowering of the CT through the tubing and maintaining a

circulation of water (up to 1500 psi), through the CT, in the well. The

fill is slowly penetrated with the help of jetting action through a jetting

nozzle attached to the end of the CT string. Gelled water is then

circulated at pressures up to 4000 psi and the jetting action causes the

fill material to become entrained in the circulating fluid and is

subsequently transported out of the wellbore through the

CT/production tubing annulus. Where consolidated fill is present, the procedure may require the assistance of a downhole motor and bit or

impact drill.




2. Wax Cleaning:-Wax cleaning is also a common operation of CTU in

which wax which is deposited on the walls of the tubing is cleared by

the help of the reciprocating movement of the CT.The wax is present

in the oil itself. This problem of chocking of tubing due wax deposition

commonly occurs in the very old well. Wax cleaning is done by

pumping very hot oil (temp upto 100) through the CT from the hot oil

circulation tank with the help of a pump.

Coil Tubing Services: (ONGC

AHMEDABAD)

As 2nd Generation Work over techniques, Coil tubing operations are

called out for well servicing without the need to subdue the well. It is

quick, efficient and cost effective.

Experience of more than 7000 jobs

Intervention in Horizontal well for stimulation / activation

Selective stimulation

Retrieval of downhole fish

Velocity string completion

Well subduing in blown out EOR wells

Development of specialized CTU tools




Conclusion

Coiled Tubing Unit (CTU) is fast becoming an indispensable tool in

the Oil and Gas Industry. It can be employed in numerous well service

operations ranging from common operations like well cleaning to very

sophisticated operations such as drilling. Rightly termed as the new

generation work-over, its versatility is, as such, unquestionable. With

the technological advances, areas that were not feasible for CT

operations in the past, can now be more efficiently serviced with CTU

and CTU related technology. The speed with which CTU operations

can be done adds to its advantage. This saves more time as well as

money as compared to conventional operations through work-over rigs.




CTU operations can also contribute more towards enhancing the

productivity when compared to traditional operations, since the risk of

damaging the formation is eliminated as the wells are not killed for such

operations.

However the vast potential that the tool offers has been underutilised

in the Indian Oil and Gas industry. With increasing awareness and rapid

globalization, this scenario is expected to improve. This is sure to

improve productivity in the industry and take it to new heights.




Nitrogen

An Introduction:-

Nitrogen is an easily available inert gas as it occupies 79% in Air by

Volume in our Atmosphere. It was discovered in 1772 by Danial

Rutherford, a Scottish Physicist. In 1883 Nitrogen was liquefied by

Wroblewski and Olszewski. Aft.er a few decades in 1955 Nitrogen was

introduced in the oil industry by Duke Bloom as cushion in drill stem

test (DST) and the following years saw a lot of development in the oil

industry using Nitrogen. Some of the developments were:

1957 - Liquid nitrogen pump & vaporizer was developed.

1959 - Nitrogen was used first time with acid.

Paul Durond developed first high volume liquid nitrogen pumps.

1960 - First liquid nitrogen unit was introduced to oil industry by

Duke Bloom and a door tothe new area of services in Petroleum

industry was opened.

1970 - First foam fracturing using Nitrogen was carried out.

Nitrogen pumper




Physical & Chemical Properties of Nitrogen:-

Colorless, odorless, tasteless, non-toxic inert gas

Neither supports combustion nor respiration

Slightly soluble in most of the liquids

Chemical Symbol: N2

Atomic Number: 7

Molecular Weight: 28.0134

Sp. gravity of gas (compared to air): 0.967

Boiling Point: (-) 195.8 °C

Sp. gravity of liquid (compared to water): 0.809

Melting Point: (-) 210 °C

1m3 of liquid N2 = 694.4 m3 of gaseous nitrogen at 15 °C & 1

atm pressure.

Cryogenics:-“The field of science that deals with the process and

technology of extremely cold materials is called Cryogenics”. The

Cryogenic Temperature Scale




upper limit of temperature usually accepted in cryogenics is -100’C (-

150’F), which by comparison is considered colder than dry ice at -78’C

(-109’F). The temperature ranges of various cryogenic gases are given

in the cryogenic temperature scale.

Oil Field Nitrogen Unit

An oil field unit may be mounted on either a semi-trailer or on a single

chassis truck or on the skid. A high-pressure pump or compressor unit

capable of delivering high-purity nitrogen gas for use in oil or gas

wells. The basic type of unit commonly available is a nitrogen

converter unit that pumps liquid nitrogen at high pressure through a

heat exchanger or converter to deliver high-pressure gas at ambient

temperature. The key components of the nitrogen unit are

Cryogenic Storage Tank:-

The cryogenic storage tank is an insulated vessel in construction and

can be regarded as being familiar to a vacuum flask. They are used to

store the nitrogen in liquid state. These vessels are of double walled

construction, inner tank being stainless steel and the outer mild steel.

The annular space between two tanks contains insulating materials

under a vacuum to reduce heat transfer.

Prime Mover:-

The trucks engine acts as the prime mover in the nitrogen pumping unit.

It runs on diesel and generates necessary power required to run the

pumps and other equipments.




Cryogenic Pump:-

The high pressure liquid nitrogen pumps are of a positive displacement

(reciprocating pump) type and are usually in a triplex configuration.The positive displacement pumps raise liquid nitrogen pressure to that

required to carry out the particular job undertaken. The liquid nitrogen

thus pumped is vaporized to a gas by the addition of heat either by a

direct fired or a flameless vaporizer.

Vaporizer:-

Vaporiser is one of the essential components of the nitrogen pumping

unit. The vaporiser (heat exchanger) is used for converting the liquid

nitrogen into gaseous form as the liquid nitrogen as such cannot be

pumped into the well bore.On the type of vaporizer system criteria,

nitrogen units are categorized as;

1. Direct fired nitrogen pumping unit

2. Non-fired nitrogen pumping unit

Nitrogen Pumper schematic




Process of Nitrogen Application:-

Nitrogen is pumped as a cryogenic liquid at around -196’C by a high

pressure cryogenic pump. Liquid Nitrogen as such cannot be pumped

into the well; it has to be converted to gas before flowing in through the

well bore. The liquid nitrogen from the cryogenic tank is pumped

through a Vaporiser (heat exchanger), which converts the liquid

nitrogen into gas with a temperature of around 21’C. The gas then flows

through the piping and flows into the well bore. The processes aremainly divided into two,

1.

Pumping System:-

Liquid nitrogen from the tank flows to a "boost pump" through

stainless steel pipes. This boost pump is a hydraulic centrifugal

pump with cryogenic liquid handling capabilities. The boost pump

raises the pressure of the liquid up to 827 Kpa (120 psi). The

nitrogen at 827 Kpa (120 psi) is then fed to a high pressure




cryogenic pump. This pump is a positive displacement "Triplex"

pump raises the pressure. From the high pressure pump the liquid

nitrogen is forced through a series of stainless steel coils which are

heated by hot air from a diesel burner. The liquid nitrogen in these

coils absorbs heat and is gasified. This duct which flows down the

line for its various service applications.

2. Vaporizer system:-

Based on the vaporizer criteria the pumping units are categorized

as:-

a.

Direct fired nitrogen pumping unit:-In Direct fired units, liquid

nitrogen from high pressure pump is forced through a series of

stainless steel coiled tubes which are heated by hot air from diesel

burner. The liquid nitrogen in these coils absorbs heat & is

gasified.




b. Non-fired nitrogen pumping unit:-The non-fired nitrogen

pumping unit works on waste heat recovery principal. This

vaporizer system uses the engine coolant (glycol / water) to

recover heat from the engine, transmission, exhaust and hydraulic

system. Heat may artificially be enhanced by drawing power from

diesel engine by means of "ALLISON TRANSMISSION

RETADER". This is the heart of the non-fired nitrogen

vaporization system.

The engine coolant temperature is about 760 C to 820 C (1700 F to

1800 F) as it leaves the engine system. Heat exchange between this

coolant and liquid nitrogen from high pressure triplex pump takes place

in a helical coiled tube heat exchanger.

Nitrogen Pumping System




Oil Field Application of Nitrogen

1. With Coil Tubing:- Nitrogen can be used with coil tubing unit for

operations like spotting acid at the desired depth, wash out sand and

silt of the bore hole, knocking out liquid from the stimulation well

and also for back wash in an injection well.

2. Displacement:- Nitrogen is used as a displacement fluid. It can be

pumped to predetermined depths knocking out the well bore liquid

(Brine/Mud) completely. Also used for spotting acid without the

displacement of WOR/Drilling fluids.

3. Nitrification of Fluid:- Nitrogen acts as a source of energy to

recover treating fluid, it improves penetration and treatment size and

also fast and efficient cleaning with reduced fluid loss.

4. Pipeline Testing and Purging:- Nitrogen being an inert, non-

corrosive and a non-explosive gas it acts as an excellent media for

pipeline and pressure vessel testing operations. It is also used for

purging flow lines and gas plant components ensuring safety in

operative conditions. Use of nitrogen in the pressure testing of plant,

pipelines, equipments etc., ensures safety and avoids internal

explosion hazards.

5. Foam Generation:- Nitrogen is an excellent Workover fluid for

sub-hydrostatic wells. Nitrogen’s use in sub-hydrostatic well

ensures minimum formation damage, low friction pressure and it’s

got an excellent sand carrying capacity with low leak off.




6. Nitrogen Lift.:- Nitrogen gas circulated into the production conduit

to displace liquids and reduce the hydrostatic pressure created by

the fluid column. Nitrogen lift.ing is a common technique used to

initiate production on a well following Workover or overbalanced

completion. A coiled tubing string is generally used to apply the

treatment, which involves running to depth while pumping high-

pressure nitrogen gas. Once the kill-fluid column is unloaded and

the well is capable of natural flow, the coiled tubing string is

removed and the well is prepared for production.

7. Nitrogen Cushion:-High-pressure nitrogen is typically applied to

a tubing string in preparation for drill stem testing or perforating

operations in which the reservoir formation is to be opened to the

tubing string. The nitrogen cushion allows a precise pressure

differential to be applied before opening flow from the reservoir.

Once flow begins, the nitrogen cushion pressure can be easily and

safely bled down to flow.

Nitrogen Service:- (ONGC AHMEDABAD)

Nitrogen is widely used for flow initiation in exploratory as well as

development wells, by unloading the well fluids as it is safe and eco-

friendly.

Experience of more than 17000 jobs

Design and fabrication of skid mounted N2 pumping system

Innovative method for prevention of LN2 resource loss.

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http://www.glossary.oilfield.slb.com/Display.cfm?Term=production

http://www.glossary.oilfield.slb.com/Display.cfm?Term=nitrogen%20lifting

http://www.glossary.oilfield.slb.com/Display.cfm?Term=workover

http://www.glossary.oilfield.slb.com/Display.cfm?Term=completion

http://www.glossary.oilfield.slb.com/Display.cfm?Term=coiled%20tubing

http://www.glossary.oilfield.slb.com/Display.cfm?Term=kill

http://www.glossary.oilfield.slb.com/Display.cfm?Term=reservoir

http://www.glossary.oilfield.slb.com/Display.cfm?Term=reservoir

http://www.glossary.oilfield.slb.com/Display.cfm?Term=kill

http://www.glossary.oilfield.slb.com/Display.cfm?Term=coiled%20tubing

http://www.glossary.oilfield.slb.com/Display.cfm?Term=completion

http://www.glossary.oilfield.slb.com/Display.cfm?Term=workover

http://www.glossary.oilfield.slb.com/Display.cfm?Term=nitrogen%20lifting

http://www.glossary.oilfield.slb.com/Display.cfm?Term=production




BIBLIOGRAPHY

WWW.ONGC.COM

en.wikipedia.org

STANDARD Handbook of Petroleum and Natural Gas Engg. -

William C Lyons

Economides

www.google.com (Source of all)

Various manual from mechanical division.

E&P Journal- March 2008 Sand control book (ONGC Dehradun)

Many more sources which can’t be explained

http://www.ongc.com/





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