A TECHNICAL PAPER

ON

“SEDIMENTARY BASINS OF INDIA”

Submitted by:

AKHILESH KUMAR MAURYA

Enrollment No: R040307003

IV semester

B.Tech (GE)

Under the guidance of

MR. M. SASI SEKHAR

Lecturer

Department of Communication.

UNIVERSITY OF PETROLEUM & ENERGY STUDIES

(ISO 9001:2000 Certified& NAAC Accredited)

Regional Center, GIET Campus, NH-5 Velugubanda Village

Rajanagaram Mandal, Rajahmundry -533294, East Godavari Dist, Andhra Pradesh.

Website: www.upes.ac.in

DECLARATION

I hereby declare that this technical paper entitled “SEDIMENTARY BASINS

OF INDIA” has been prepared by me during the months of April-May 2009

under the Guidance of Mr. M. SASI SEKHAR (faculty member) to fulfill the

requisites for the paper of technical communication.

I also declare that this project is a result of my own effort and that it

has not been submitted to any other University or published any time before.

Place: RAJAHMUNDRY

Date: AKHILESH KUMAR MAURYA

ACKNOWLEDGEMENT

With completion of report on “Sedimentary Basins Of India” I would like to express my

gratitude to all of people who helped me and guided.

I extend my gratitude to our Technical Communication faculty Mr. M. SASI SEKHAR,

Lecturer, Dept. of Comm for his support and guidance throughout the period.

I also would like to extend my thanks to Ms. M. Harsini Devi, Lecturer, Dept. of Comm. For

extending kind support.

Last but not the least I would like to thank Mr. Kumar Abhinav, (MBA-UAM) who guided me

throughout the project .

I would like to thank all once again.

Akhilesh Kumar Maurya

INTRODUCTION Based on the exploration carried out so far and status of knowledge in terms of occurrence of hydrocarbon sedimentary basin of India is divided into 4 categories.

Category-I

The petroliferous basin with proved hydrocarbon reserves and where commercial production has

already started.

These basins are:

Assam shelf

Bombay offshore

Cambay

Krishna-Godavari

Tripura

Category-II

Sedimentary basin with proved occurrence of hydrocarbons but from which no commercial

production has been obtained yet.

These basins are:

Andaman – Nicobar

Bengal

Himalayan Foothills

Jaisalmer

Kutch

Mahanadi

Category-III

Sedimentary basins with no significant oil & gas shows but which on Geological considerations

are considered to be prospective.

These basins are:

Bikaner-Nagpur

Kerala-Lakshadweep

Saurashtra

Category-IV

Petroliferous basins with uncertain prospects which require basic data to be generated for

prognosis. It includes the basins which bear an analogy with similar hydrocarbon producing

basins in the world and may be prospective.

Arunachal Foothills

Deccan Syncline

Ganga Valley

Gondwana

Kashmir valley (Karewa)

Mizoram

Manipur

Narmada

Vindhyan

Assam –Arakan Basin

Geological Setting:

It includes Assam, Nagaland, Arunachal Pradesh, Manipur, Mizoram and Tripura. The eastern

limit is defined by Patkai, Barali and associate ranges forming the Nagga hills and to the north,

Himalayas culminating in Narmcha Barwa. The principal oil fields of OIL & ONGC, to the

South-West lie in the Mikir Hills which are probably the North-Eastern prolongation of the

Indian Shield.

The Assam shelf has an extent of 40,000 sq.km. and includes the Shillong Plateau, the Garo,

Khasi, Jaintia, Mikir Hills and the upper Assam valley. The Southern edge of the platform is

demarcated by the mobile belt of the Assam-Arakan Geosyncline with very thick molasse and fly

ash sediments of Cretaceous and Tertiaryage. The shelf sediments of the same age also observed

in outcrop in Mikir Hills and Shillong plateau. The Geosynclinal sediments are exposed in South

of Naga thrust.

The Dauki Fault separates the sediments of Bengal Basin from exposed shelf sediments leaving

platform closed by the convergence of Himalayas and Naga Hills in the North-East in the area of

Minshmi Hills of Arunachal Pradesh.

GEOLOGICAL EVOLUTION OF UPEER ASSAM SHELF

Pre – tertiary

it comprises of Precambrian Quartz and other metamorphic rocks. It also consists of some lava

flows of Jurasic age and lower gondwana beds in Eastern Himalayas.

Tertiary sediments

It consists of a shelf facies and geosynclical facies. The shelf facies is found in the Shilong

Platue and the Mikir Hills whereas geosynclinals facies are found in Naga Hills. Both of facies

are separated by Schuppen Belt.

Paleocene- Eocene Deposition

The development of this basin started with the deposition of Basal sandstones and Sylhet

Limestones In Paleocene- Eocene time. The deposition was lagoonal to shallow marine.

Eocene- Oligocene deposition.

Kopili and barail formations were deposited during this age. The shelf was unstable.sedimantion

kept pace with subsidence intermittent period of slight emergency of the basin during this

period.

Milo- Pilocene deposition

Miocene sediments are represented by Surma and Tipam groups of sediments. Surma is

identified by inter bedded sand stone & shales and change in heavy mineral.

Tipam group is further subdivided in 4 formations: geleki sandstone, Lakwa sandstone, Girujan

sandstone and Nazira sandstone. The Tipam sediments of Mio-Pliocene age were deposited

disconformably over partially eroded Barail surface with an overlap towards North-West. Tipam

sediments were deposited mainly in fresh water environmental but influence of some back water

was also observed. All oil producing sands of Digboi oil field lie in this group and in

underlying Suramas.

In the Mio-Pliocene and later orogenic phases, the northern rim and part of the eastern rim of the

Assam-Arakan basin were raised and driven forward in a series of overthrust masses towards and

over a comparatively stable spur forming part. of the Indian shield.

During this period, some of the criss-cross basement controlled faults got reactivated and

resulted in formation of structures like Geleki, Lakwa etc.

The tectonic movements during this period also resulted in initial formation of the Brahmaputra

Arch and the fore deep in front of the rising Himalayas.

During the Plio-Pleistocene time, Assam platform formed part of the frontal deep of the

Himalayas and was consequently depressed northwards. It accommodates a huge thickness of

molasses derived from the rising Himalayas. During the same time, intense orogenic activity was

observed in the Naga Mobile Belt.

Habitat of oil in Upper Assam Shelf

The habitat of oil mainly depends on basinal configuration and stratigraphic occurrence. As per

recent studies it is found that towards the shelf-geosynclinal margin, Tipam oil and gas

accumulation increases in frequency and volume (Lakwa, Geleki, Jorajan).

The Lakwa & Geleki have oil accumulation both inBarail and Tipam reservoirs.

The Argillaceous beds of Lower Tertiary age are the main source rocks for hydrocabon

generation in this field.

THE CAMBAY BASIN

Geological Setting The Cambay Basin occupies an area of approximately 56,000 sq.km. The Cambay Basin is an

intra -cratonic graben and bounded by series of faults one after another paralleling the Dharwar

trend and cuts across the Narmada and Aravalli trends. This basin extends to the North in

offshore as a narrow graben. The graben is parallel with the

coast between mainland and Bombay High.

The Cambay Basin can be divided into six tectonic blocks :

Sanchor block

Tharad block

Ahmedabad-Mehsana block

Tarapur block

Broach block

Narmada block.

Stratigraphy The Cambay basin has developed in three structural stages. The lower stage is represented by

Mesozoic rocks, middle stage by thick basaltic lava flow which is better known as Deccan Trap

and finally upper stage represented by Neogene sequences. The Mesozoic rocks are exposed in

the Western and Southern part of the basin and also encountered during drilling in the North-

West part of the basin.

The sedimentary sequences found in this basin may be classified into six major stratigraphic

units.

Mesozoic sedimentary sequence.

Paleocene-Lower Eocene sequence.

Lower to Middle Eocene sequence.

Middle and Upper Eocene sequence.

Late Eocene to Early Oligocene sequence.

Neogene sequence.

Hydrocarbon habitat in Cambay Basin The Cambay Shale is the main source rock in this basin. The organic matter content averages to

2.5% and mainly of sapropelic and humic in nature. The sandstone and siltstone of Ankleshwar,

Kalol and Kadi Formations are the main reservoir rocks in this basin.

The traps are structural, stratigraphic and combination type in this basin. Cambay Shale acts as

cap rock for hydrocarbon deposits in Kadi Formation and VagadKhol Formation, whereas in the

northern part, Tarapur Shale acts as cap rock. Telwa Shale of Ankleshwar Formation and Kanwa

Shale in South of Mahisagar river also serve as cap rock

BOMBAY OFFSHORE BASIN The Bombay offshore region of the western continental shelf of India forms an important

hydrocarbon bearing province and comprises sediments of Cenozoic age.

This basin is extending from Saurashtra Coast in the North to Vengurla arch near Goa in the

South. It covers an area of about 1,20,000 sq.km. upto 200 m isobaths.

Geological Setting Evolution of Bombay Offshore started during break-up of Gondwana Land in Late Cretaceous.

This basin experienced deposition of thick Tertiary sedimentary sequences over a predominantly

Deccan Trap floor. Tectonically I the basin can be subdivided into Surat depression, Bombay

High platform, Ratnagiri block, Shelf margin basin and the Shelf-edge basement arc.

Stratigraphy The sedimentary sequences deposited in this basin are of Paleogene and Neogene age which are

at places more than 5000 m thick. However, the thickness of sediments over the giant oil field

"Bombay High" is considerably less and vary in thickness from 1800 m -2000 m.

(1) Basement: The Archean basement is present over the paleohigh (viz. Bombay High,

Heera) and encountered in some of the wells directly below the Tertiary sediments.

(2) Paleocene-Lower Eocene sedimentarysequence: This unit is represented by Panna,

Jafarabad and Devgarh Formations.

Panna Formation is spread over the entire Bombay Offshore Basin excepting the

Paleohighs. It is represented by sandstone, claystone, shale andn coal bed at the middle.

It overlies Deccan Trap or Archean basement and is overlain unconformably by

Bassein/Belapur/Pipavav Formation which coincides with H-4 seismic marker. This

formation has deposited in shallow marine environment.

(3) Middle Eocene-Upper Eocene sequence: The Middle Eocene is represented by

Belapur Formation and Bassein Formation in Bombay Offshore Basin. The Belapur

Formation extends over Tapti-Da~an block, Mahim, Shelf margin and Diu block. It

unconformably overlies the Panna Formation qnd is overlain by Bassein Formation and

Diu Formation. Calcareous shale, claystone and limestone constitutes the dominant

lithology.

The Bassein Formation is present throughout the Basin except in Tapti- Daman, Diu,

Bombay High and eastern part of South Ratnagiri. The Bassein Formation is represented

by limestone(porous packstone to wackestone). This formation is unconformably

underlain by Panna Formation and the H-4 seismic marker corresponds to the contact

between the two.

(4) Lower Oligocene sequence: This unit is represented by Mahuva Formation, Mukta

Formation and Heera Formation. The Mahuva Formation extends over Tapti-Daman

block and Diu block and is represented by shale with thin streaks of limestone.

Limestone generally disappears in Tapti area and shale becomes silty. This formation

has deposited in deltaic to inner neritic depositional environment.

Mukta formation is present in most part of the Bombay Offshore Basin excepting

Tapti- Daman block. It has sharp but comfortable relation with underlying Heera

formation. The formation consist of Argillaceous limestone.

(5) Upper Oliocene to Basal Miocene sequence: this unit is represented by Daman

formation in Tapti- Daman block, Alibag formation in Panna- Bassein block, Shelf

Margin block, Diu block, eastern part of Bombay high- DCS block, Eastern and central

part of Ratnagiri Block and Panvel formation in most part of Bombay High-DCS block,

western part of Ratnagiri block.

(6) Lower Miocene sequence: this unit is represented by Bombay Formation, Mahim

Formation and Ratnagiri Formation (lower- middle Miocene).

The Bombay Formation extends over eastern part of Bombay High-DC8 block, most of

Diu block and parts of Panna-Bassein block and is represented by mainly limestone

interspersed with thin shale layers. It has good porosity.

Mahim Formation is underlain by Bombay Formation with conformable contact in

central part of the Bombay Offshore Basin but unconformably underlain by

Daman/Alibag Formation and overlain by Tapti Formation. This formation consists

dominantly of shale with a few siltstone and limestone layers.

(7) Middle Miocene Sequence: This unit is represented by Tapti Formation and Bandra

Formation in Bombay Offshore Basin. The Bandra Formation deposited over Diu,

Bombay High, DCS and southern part of Panna-Bassein block consists mainly of

limestone with thin shale layers.

(8) Upper Miocene to Recent sequence: The Chinchini Formation is present through out

the

Bombay Offshore Basin. The formation consists of soft, sticky clays with intercalations

of claystone `and shale. Its contact with underlying litho units is characterised by a

regional unconformity. This formation has deposited in shallow marine environment

varying from inner neritic to outer neritic.

HABITAT OF HYDROCARBON IN BOMBAY OFFSHORE BASIN Bombay Offshore Basin is producing nearly 70% oil and gas of India’s toltal hydrocarbon

production. The Bombay High is the only giant oil field so far discovered in Bombay offshore

Basin as well as in India. The medium sized Oil field are Panna, Neelam, Heera and Ratnagiri.

The Bassein, Daman, Mid Tapti and south Tapti are the major gas fields in this basin.

The major Producing horizons are Miocene limestone(Bombay High), Middle Eocene(Ratnagiri,

Panna, Mukta, Neelam, Bassein, Heera), Oligocene (Tapti- Daman) and other sequences.

The main source rock of Hydrocarbon generation is the pre-Middle Miocene shales in the Surat

Depression and Shelf Margin area. The Shales alternate with the limestone, deposited in local

depression of the above age, also act as source rock. The limestone of early Miocene- Eocene

sequence also contributed for hydrocarbon generation.

The main reservoir rock in this basin is limestone sequence of different ages. In addition to it,

sand, stone and siltstone sequence also occur as reservoir rocks( Daman, Tapti and Basal Clastics

etc.) . the post middle Miocene Shales mainly act as a cap rock in the basin.

KRISHNA GODAVARI BASIN Geological Setting Krishna – Godavari Basin encompasses an area of about 15,000 sq. km. of onland and the East-

coast of India, West and North western limits are demarcated by Archaean outcrops.

To the east it exerted offshore into shelf. To the North, it is delimited by Pitha-puram cross trend.

The southern limit of the basin is demarcated by Pennar and Krishna ridge faults. The basin is

divided into six sub-basin by ridges, faults and Archaean outcrops.

(1) Mandapeta Sub-basin

(2) West Godavari sub-basin

(3) East Godavari sub-basin

(4) Krishna sub-basin

(5) Nizamapatnam sub-basin

Startigraphy (1) Pre-Cambrain metamorphic complex

(2) Lower Gondwana group (Premian- Triassic)

(3) Nizampatnam Group (Jurassic to Early Cretaceous)

(4) Gudivada Group (Early to Late Cretaceous)

(5) Vasishta Group (Paleocene to early Miocene)

(6) Gowthami Group (Oligocene to Pilocene)

(7) Andhra Alluvium (Quaternary)

HYDROCARBON HABITAT IN KRISHNA-GODAVARI BASIN Qualitatively the Paleocene- Eocene shale and possibly the Eocene limestone can considered

good source rocks for the generation of oil. The deltaic sediments themselves could generate

hydrocarbon in still deeper parts of the basin where they were likely to have reached thermal

maturity.

The cretaceous section in a large part of the basin can be considered to have given rise to gaseous

hydrocarbon from its predominant humic organic content.

Cretaceous clastics, platform facies, Late tertiary clastics serve as reservoir rocks. The offshore

producing field ‘Ravva’ consists of thin and thick layers of sandstone alternating with thick clay

section.

LITHO-STRATIGRAPHIC SECTION ALONG A NE – SW PROFILE,

KRISHNA GODAVARI BASIN

NW-SE GEOLOGICAL CROSS SECTION, KRISHNA GODAVARI

BASIN

CAUVERY BASIN

The Cauvery Basin, situated 160 to 460 km south of Madras city, encompasses an area of 25,000

sq. km. falls in Indian territorial waters.

The basin is limited with West and Northwest by the basin margin fault and basement outcrops.

In the East, it is limited by the Srilankan Massif and the basin margin fault with southern part,

while the basin extends offshore on the shelf with northern part. Towards south the basin extends

upto the Gulf of Mannar.

The basin is subdivided into six sub-basin:-

I. Ariyalur Pondicherry sub-basin.

II. Tranquebar sub-basin

III. Thannjavur sub-basin

IV. Nagapatinam sub-basin

V. Ramnad Palk Bay sub-basin

VI. Mannar sub-basin

Stratigraphy Pre-Cambrian Metamorphic Complex

Upper Gondwana Group

Uttatur Group (Early Cretaceous)

Ariyalur Group (Late Cretaceous)

Nagore Group (Paleocene to Eocene)

Narimanam Group (Oligocene to Recent)

HYDROCARBON HABITAT IN CAURVEY BASIN The potential source beds in the Cretaceous section must have generated hydrocarbons.

Moderately lean, gas prone thermally immature source rocks are also present.

Clastic reservoir rocks are generally developed along the western margin of the Cauvery Basin

and along the flanks of the substance ridges.

Good development of suitable traps are expected in the basin due to basement drape, tilting and

faulting growth faults and diapirism in deltaic sequence, updip seals of porous clastics and

carbonates and onlap by major shales over sloping basement.

FIG: CAURVEY BASIN