SEDIMENTARY BASINS OF INDIA, CATEGORIZATION AND HYDROCARBON POTENTIALBYN.S.RANACG, KDMIPE, ONGCDEHRADUN--/--/2013

MBA Basin, Kolkata

The Indian scenario of Sedimentary Basins

India is having vast Onland and Offshore area covered with sedimentary rocks.

(Total: 3.14 million Sq Km, ie. 4.07% of the worlds total sedimentary area)

MBA Basin, Kolkata

WHAT IS SEDIMENTARY BASIN ?

Sedimentary basins are Geosynclines, creating accommodation space for infilling the sediments.

Sedimentary basins occur in diverse geological settings usually associated with plate tectonic activity.

MBA Basin, Kolkata

TILL 1960, THE SEDIMENTARY BASINS WORLD WIDE - EXPLAINED IN TERMS OF GEOSYNCLINAL THEORY.

WITH THE DEVELOPMENT OF PLATE TECTONICS, UNDERSTANDING ON THE EVOLUTION OF THE BASINS, THEIR STRUCTURAL STYLES AND ASSOCIATED LITHOFACIES HAVE BECOME MUCH CLEARER.

MBA Basin, Kolkata

MBA Basin, Kolkata

Sedimentation pattern in half graben set up

MBA Basin, Kolkata

Sedimentary Depositional Environments (Clastics)The figure shows schematic representation of sedimentary environments which can be grouped as:

ContinentalTransitionalMarine**

MBA Basin, Kolkata

Sedimentary Depositional System in Offshore

MBA Basin, Kolkata

Explored / Unexplored Basin AreaIndian Sedimentary Basins

MBA Basin, Kolkata

EVOLUTION OF A SEDIMENTARY BASIN

FOUR INDEPENDENT FACTS (DICKINSON, 1976) GEOMETRIC SHAPE AND SIZE OF THE BASIN

NATURE OF THE SEDIMENTARY FILL

THE STRUCTURAL STYLES

AND THE THERMAL HISTORY

MBA Basin, Kolkata

A number of basins formed in extensional settings can undergo inversion, which has accounted for a number of the economically viable oil & Gas reserves on earth.

MBA Basin, Kolkata

Total 26 sedimentary basins have been recognized and they are divided into four categories based on their degree of hydrocarbon prospectivity.

The sedimentary basins of India, onland and shallow offshore, up to the 200m isobath, area is about 1.79 million sq. km.

In the deep water offshore beyond the 200m isobath, the sedimentary area has been estimated about 1.35 million sq. km.

The total area of sedimentary basins in Indian scenario works out to 3.14 million sq. km. Sedimentary Basins Of India

MBA Basin, Kolkata

Category- I Basin is the petroliferous basins with proved hydrocarbon reserves and where commercial production has already started. These basins are: Assam shelf, Tripura, Bombay offshore, Cambay, Cauvery and Krishna-Godavari Basins.

Category II basin comprises with occurrence of hydrocarbons but from which no commercial production has been obtained yet. These basins are: Kutch-Sourashtra & MBA( Mahanadi, Bangal & Andaman) Basins.

Category III basin comprises with no significant oil & gas shows but which are considered to be prospective on G&G analysis. These are mainly todays Frontier basins : Himalayan foreland, Ganga Basin, Vyndhyan basin etc.

Category IV basin comprises uncertain prospects. It includes the basins which bear an analogy with hydrocarbon producing basins in the world. Ie. Deccan Plateau, Cuddapah & Chattisgarh Syncline etc.CATEGORIZATION OF INDIAN SEDIMENTARY BASINS

MBA Basin, Kolkata

MBA Basin, Kolkata

Category-I (Proven Commercial Productivity)

Basin NameOnland AreaOffshore AreaTotalAssam-Arakan1,16,000-1,16,000Cambay51,0002,50053,500Cauvery25,00030,00055,000Krishna Godavari 28,00024,00052,000Mumbai Offshore-1,16,0001,16,000Rajasthan1,26,000-1,26,000

MBA Basin, Kolkata

CATEGORY- II

BASINS WITH KNOWN ACCUMULATION OF HYDROCARBON BUT FROM WHICH NO COMMERCIAL PRODUCTION.

8. KUTCH 9. MAHANADI 10. ANDAMAN-NICOBAR

MBA Basin, Kolkata

Category-II (Identified Prospectivity)

Basin NameOnland AreaOffshore AreaTotalKutch35,00013,00048,000Mahanadi55,00014,00069,000Andaman Nicobar6,00041,000

47,000

MBA Basin, Kolkata

CATEGORY-III

BASINS GEOLOGICALLY CONSIDERED PROSPECTIVE WITH HYDROCARBONS.

11. HIMALAYAN FOOTHILLS 12. GANGA BASIN 13. VINDHYAN 14. KUTCH-SAURASHTRA 15. KERALA-KONKAN-LAKSHWADEEP 16. BENGAL

Todays frontiers may tomorrows cat. I.. 111216131415

MBA Basin, Kolkata

Category-III (Potentially Prospective Basins)

Basin NameOnland AreaOffshore AreaTotalBengal57,00032,00089,000Ganga Valley1,86,000-1,86,000Himalayan Foreland30,000-30,000Kerala-Konkan Lakshdweep-94,00094,000Saurashtra52,00028,00080,000Vindhyan1,62,000-1,62,000

MBA Basin, Kolkata

CATEGORY- IV

BASINS WITH UNCERTAIN PROSPECTS WHICH MAY BE PROSPECTIVE ON ANALOGY WITH SIMILAR BASIN IN THE WORLD.

17. KAREWA 18. SPITI- ZANSKAR 19. SATPURA- SOUTH REWA- DAMODAR 20. NARMADA 21. DECCAN SYNECLISE 22. BHIMA- KALADGI 23. CUDDAPAH 24. PRANHITA- GODAVARI 25. BASTAR 26. CHATTISGARH

MBA Basin, Kolkata

MBA Basin, Kolkata

Category-IV (Potentially Prospective )

Basin NameOnland AreaOffshore AreaTotalBastar5,000-5,000Bhima-Kaladgi8,500-8,500Chattisgarh32,000-32,000Cuddapah39,000-39,000Deccan Syncline2,73,000-2,73,000Karewa3,700-3,700Narmada17,000-17,000Pranhita-Godavari15,000-15,000Satpura-South Rewa-Damodar46,000-46,000Spiti-Zanskar22,000-22,000

MBA Basin, Kolkata

DEEP WATER BASINS

WESTERN OFFSHORE BASIN

Mumbai Offshore and Kerala Kankan Offshore

In Western offshore basin the reservoirs are mainly carbonates and maximum production of oil is from this basin.

MBA Basin, Kolkata

DEEP WATER BASINS

EAST COAST OFFSHORE BASINS

Cauvery Offshore KG Offshore and MBA Offshore

In East cost offshore the reservoirs are mainly Clastics and & rich in gaseous hydrocarbon.

MBA Basin, Kolkata

Indian Sedimentary BasinsDeepwater: 1,350,000 Sq.Km

MBA Basin, Kolkata

ASSAM AND ASSAM-ARAKAN BASIN

* ASSAM SHELF

* ARAKAN FOLD BELT

MBA Basin, Kolkata

MBA Basin, Kolkata

WESTERN ONLAND BASIN Rajsthan Basin

Cambay Basin

Kutch Basin

Saurastra Basin

MBA Basin, Kolkata

Rajasthan Basin( Jaisalmer, Bikaner-Nagour and Barmer Basins)

MBA Basin, Kolkata

THE RAJASTHAN SHELF IS CARVED OUT INTO A NUMBER OF BASINS

JAISALMER BASIN

BIKANER-NAGAR BASIN

BARMER BASIN

MAJOR OIL AND GAS FIELDS

GHOTARU, KHARTAR, BANIKA, BAKHRI TIBBA, SADEWALA TIBBA, CHINNEWALA TIBBA, MIAJALAR.

MBA Basin, Kolkata

MBA Basin, Kolkata

THE CAMBAY BASIN :

The Cambay Basin occupies an area of approximately 54,000 sq.km.

The Cambay Shale is the main source rock in this basin.

MBA Basin, Kolkata

CAMBAY BASIN DIVIDED INTO FIVE TECTONIC BLOCKS FORM NORTH TO SOUTH:

1. SANCHOR PATAN BLOCK

2. MEHSANA AHMEDABAD BLOCK

3. TARAPUR CAMBAY BLOCK

4. JAMBUSAR BROACH BLOCK

5. NARMADA TAPTI BLOCK

MBA Basin, Kolkata

MBA Basin, Kolkata

MAJOR OIL FIELDS OF CAMBAY BASIN

MEHSANA BLOCK- N. KADI, SANTHAL, BALOL, SOBHSAN, NANDASAN, LINCH, JOTANA, BECHRAJEE, LANGHNAJ, MANSA, MEWAD etc.

AHMEDABAD BLOCK- KALOL, WADU- PALIYAD, NAWAGAM, NANDEJ, AHMEDABAD, WASNA, JHALORA, SANAND, LIMBODRA, GAMIJ, ASMALI etc.

ANKLESHWAR BLOCK- ANKLESHWAR, MOTERA, SISODRA, KIM, KOSAMBA, GANDHAR, PAKHAJAN, NADA, DABKA, JAMBUSAR, PADRA, KARZAN etc.

MBA Basin, Kolkata

WESTERN OFFSHORE BASIN

Mumbai Offshore Basin

&

Keraka-Konkan Offshore Basin

MBA Basin, Kolkata

BOMBAY OFFSHORE BASIN:

It lies in region of Western continental shelf of India and forms an important hydrocarbon bearing province.

It is extending from Saurashtra Coast in the North to Vengurla arch near Goa in the South covering an area of about 1,20,000 sq.km. up to 200 m isobaths.

Tectonically the basin can be subdivided into Surat depression, Bombay High, Ratnagiri block, Shelf margin basin and the Shelf-edge basement arc.

Bombay Offshore Basin is producing nearly 70% oil and gas of Indias total hydrocarbon production. Major reservoirs are the Carbonates.

MBA Basin, Kolkata

WESTERN OFFSHORE BASIN(Mumbai Offshore)

MBA Basin, Kolkata

MID MIOCENEEARLY MIOCENE

MBA Basin, Kolkata

LATE OLIGOCENEEARLY OLIGOCENE

MBA Basin, Kolkata

MID-LATE EOCENELATE PALEOCENE-EARLY EOCENE

MBA Basin, Kolkata

Gas

Dry

Oil

Prospects in Bombay Offshore Basin

MBA Basin, Kolkata

EAST COAST BASINS

CAUVERI BasinKG-PG BasinMBA Basin

MBA Basin, Kolkata

CAUVERY BASIN The Cauvery Basin encompasses an area of 55,000 sq. km.

The basin is subdivided into six sub-basin:-

Ariyalur Pondicherry

2. Tranquebar

3. Thannjavur

4. Nagapatinam

5. Ramnad Palk Bay

6. Mannar sub-basin.

MBA Basin, Kolkata

MBA Basin, Kolkata

GENERALISED STRATIGRAPHY OF CAUVERY BASIN

MBA Basin, Kolkata

3D view at Basement level showing various structural elements Cauvery basin, indiaPattukottai ridgeKumbakonam ridgeKaraikal ridgeVedaranyam ridgeTranquebar sub-basinNagapattinamSub-basin**

MBA Basin, Kolkata

MAJOR OIL AND GAS FIELDS OF CAUVERI BASIN

NARIMANAM,ADIYAKKAMANGALAM, NANNILAM, MATTUR, KAMLAPURAM, KUTHANALUR,TIRVARUR, KOVILKALAPPAM, BHUVNAGIRI, VIJAYAPURAM, PUNDI, KUTHALAM, RAMNAD etc.

MBA Basin, Kolkata

BAPATLA HIGHKAZA KAIKALUR HIGHTANUKU HIGHPLK-MTP FAULTGUDIVADA GRABENBANTUMILLI GRABENKG-PG Basin

MBA Basin, Kolkata

KRISHNA GODAVARI BASINThe Krishna Godavari Basin is a proven petroliferous basin of continental margin located on the east coast of India.

Its onland part covers an area of 28,000 sq. km and the offshore part covers an area of 25,000 sq. km up to 1000 m isobath.

The basin contains about 7km thick sediments with several cycles of deposition and H/C occurrences ranging from Permo-Triassic(Gondwana) to Plio-Pleistocene age .

MBA Basin, Kolkata

Geological map: KG-PG Basin

MBA Basin, Kolkata

Geological/ Geophysical Surveys: ONGC has carried out detailed geological mapping in the area covering 4220 sq. km since 1959.

MBA Basin, Kolkata

Gravity-Magnetic surveys, in onland part have been carried out by ONGC over an area of 19,200 sq. km.

In offshore area, M/s. Prakla Seismos and GSI acquired the gravity-magnetic data for ONGC.

Composite Bouguer gravity & composite magnetic anomaly map

MBA Basin, Kolkata

MBA Basin, Kolkata

KRISHNA GODAVARI BASIN :

This basin is divided into six sub-basins: 1. Mandapeta Sub-basin, 2. West Godavari sub-basin, 3. East Godavari sub-basin, 4. Krishna sub-basin, 5. Nizamapatnam sub-basin & 6. K.G. Offshore sub-basin: -shallow offshore, -deep offshore and -ultra-deep offshore.

MBA Basin, Kolkata

MBA Basin, Kolkata

MBA Basin, Kolkata

*Envisaged Depositional Model The environment of deposition has been envisaged to be fluvial to transitional during the earlier period of graben formation and transitional to marginal marine during the later stages. Sands within the syn rift are derived from the rift shoulders, deposited as basin fan floor complexes, slope fan complexes. Deposited as alluvial fans/ braided fluvial fans, prograding as lobes with intervening lacustrine facies. Also, deltaic fan under marginal marine environment.

MBA Basin, Kolkata

More than 225 prospects have been probed by drilling of more than 557 exploratory wells. Hydrocarbon accumulations have been proven in 75 of these prospects (22 oil & 53 gas).

Notable oil discoveries are Kaikalur, Vadali, Mori, Bantumilli, Lingala, Suryaraopeta, Gopavaram, Kesanapalli, and Kesanapalli West. The gas discoveries are Adavipalem, Elamanchili, Enugupalli, Narsapur, Razole, Tatipaka-Kadali, Pasarlapudi, Mandapeta, Chintalapalli. Nandigama, Endamuru, Penumadam, Ponnamanda, Achanta, Mullikipalle, Magatapalli, Gokarnapuram, Kesavadasapalem, Lakshamaneshwaram, Rangapuram and Sirikattapalli.

In onshore, so far 141 prospects have been probed by 375 exploratory wells by ONGC, out of which 11 oil & gas pools and 31 gas pools have been discovered and most of them are on production.

In offshore, so far more than 84 prospects have been probed by 182 exploratory wells . Hydrocarbon accumulations have been proved in 33 of these prospects (11 oil & gas and 22 gas prospects).

MBA Basin, Kolkata

AREA- 52, 000 Sq.Km (ONLAND- 28,000 & OFFSHOE- 24,000) TYPE- COMPOSITE BASIN

RESERVES- 46.22 (O+OEG)

RESOURCES- 1130 MMt

EXPLORATION OBJECTIVES -

MESOZOIC STRUCTURAL PROSPECTS ASSOCIATED WITH RIDGES (ONSHORE). PALEOCENE/ EOCENE CARBONATE BUILD-UP (OFFSHORE). ROLLOVER ANTICLINES (OFFSHORE). EOCENE DELTAIC SEQUENCE ON SHALLOWER SHELF (OFFSHORE). MIOCENE DELTAIC SANDS (OFFSHORE). PLIOCENE PINCHOUTS.

MBA Basin, Kolkata

MBA Basin, Kolkata

KG LOCATION MAP WITH DEEP WATER NELP BLOCKS

MBA Basin, Kolkata

MBA Basin, Kolkata

MBA BasinsThe Mahanadi Basin is located on the eastern sea board of India and covers the coastal districts of Orissa State and adjoining offshore areas in Bay of Bengal. In the land part, it covers an area of about 55,000 Sq.Km. Its boundaries in the north, west, and south are marked by outcrops of Precambrian rocks and in the east the basin extends into Bay of Bengal, having an area of about 14000 Sq.Km.

MBA Basin, Kolkata

MAHANADI MAP WITH NELP BLOCKS

MBA Basin, Kolkata

Bangal Onland BasinBangal Offshore Basin

MBA Basin, Kolkata

Andaman Offshore Basin

MBA Basin, Kolkata

Hydrocarbon Potential & Prospectivity of sedimentary Basins

MBA Basin, Kolkata

What is a Prospect ? Independent accumulation of oil, gas, oil & gas pools in a sedimentary basin

There could be several prospects in sedimentary basin

Size of prospect very from few sq km to thousands of sq km.

MBA Basin, Kolkata

Prospects Identification

To identify the possible hydrocarbon locales/area through Integrated Interpretation of multi-disciplinary data (Geological and Geophysical data)

MBA Basin, Kolkata

Types of Prospects:

Oil prospectGas prospectOil & Gas prospect

MBA Basin, Kolkata

Geological Aspects: Prospect AnalysisSource Rock EvaluationPresence of Reservoir RocksPresence of Cap rock or SealsTraps ( Structural / Stratigraphic)H/C charges and Timing

MBA Basin, Kolkata

REQUIREMENTS FOR HYDROCARBON ACCUMULATIONIn a basin there must be adequate thickness of sediments.There must be adequate organic material trapped in those sediments. There should be conditions of burial and favourable temperature long enough for generation of oil. Once oil is generated it migrates out of the source rocks. There should be adequate reservoir rocks for holding this oil.There should be adequate sealing above reservoir rocks to form traps.

MBA Basin, Kolkata

Rocks that contain sufficient amount of Kerogen are called Source Rock

When a source rock starts generating oil and gas then it is said to be mature. When the Kerogen is further heated with time, the chains of HC break away from the Kerogen and form waxy and viscous crude oil.

Source Rock

MBA Basin, Kolkata

Source Rock Evaluation

Total quantity of organic matter

Type of organic matter

Maturity of organic matter

Generative capacity of the basin

MBA Basin, Kolkata

Reservoir Rocks:

The essential element of petroleum accumulation is Reservoir and essential features of a reservoir rock is Porosity i.e its ability to store fluid.

Sandstones: 59% Carbonates: 40% &Other fractured rocks: 1%

MBA Basin, Kolkata

RESERVOIR ROCKS A rock with enough porosity to be capable of storing economic quantities of petroleum, and enough permeability to transmit flow of hydrocarbons. POROSITY :

The total sum of opening or voids that occur within a rock. Usually expressed as a decimal percent. Porosity is denoted by phi () and is given by the equation = Bulk Volume Grain Volume x 100 Bulk VolumeEFFECTIVE POROSITY :

Porosity that is available for storage of fluids.

MBA Basin, Kolkata

What is good porosity?0-5% - Negligible 5-10%- Poor 10-15%- Fair 15-20%- Good >20% - Very good

Practical cut off for oil Sandstone ~8% Limestone ~5% For gas the cut off is lower

MBA Basin, Kolkata

Cap Rocks

The cap/seal rocks have pore throats too small and poorly connected to allow the passage of hydrocarbons. The geographical extent of seal rocks defines the effective limits of the Petroleum system.

MBA Basin, Kolkata

Traps

Traps are the geometric arrangement in which petroleum accumulation takes place.

Petroleum expelled from an active source rock (Primary migration) migrate along a fault plane or a permeable carrier bed (secondary migration to a porous reservoir rock) capped or surrounded by a comparatively impervious seal that together form a trap.

MBA Basin, Kolkata

Prospect types:Structural prospect (Structural Entrapment )

Stratigraphic Prospect (Entrapment is stratigraphic)

Stati-structural prospect (Entrapment combination of structural & stratigraphic)

MBA Basin, Kolkata

ANTICLINAL TRAP SHOWING DISTRIBUTION OF OIL, GAS AND WATER

MBA Basin, Kolkata

Structural Prospect: Fault Trap

MBA Basin, Kolkata

Structural Prospect: Salt Dome

MBA Basin, Kolkata

Stratigraphic Prospect:

MBA Basin, Kolkata

Stratigraphic Prospect:

MBA Basin, Kolkata

Diagenetic traps:

This area more common in carbonate reservoirs which are more easily affected by cementation, dissolution and dolomitization. These post-depositional processes lead to a lateral change in reservoir quality to acts as the trapping mechanismStratigraphic Prospect:

MBA Basin, Kolkata

Structural Prospect: Fold Trap

MBA Basin, Kolkata

Oil & Gas accumulations are governed by an intricate mechanism of generation, migration and entrapment with uniquely subjective boundary conditions that are not so exacting

MBA Basin, Kolkata

act of searching thoroughly and/or travel for the sake of discovery - Chambers

MBA Basin, Kolkata