Exploration in Sedimentary Basins of India for oil and gas: A future

perspective

ByRoshan Vishwakarma

E-mail: roshan_geo07@yahoo.com

Contents

Chapter 1) IntroductionChapter 2) Categorization of sedimentary basins Chapter 3) The petroliferous basins of IndiaChapter 4) Hydrocarbon Potential of IndiaChapter 5) Production and Consumption of Petroleum (crude) and Natural gasChapter 6) Perspective plans of exploration and development for hydrocarbons Summary References

Chapter 1: Introduction • It is well known that the oil has been mostly generated and

accumulated in the sedimentary rocks, the world over.• Sedimentary basins are in a broad sense, all those areas in which

sediments can accumulate to considerable thickness and be preserved for long geological time periods.

• In India, hydrocarbons have been struck in different basins ranging in age through out the Phanerozoic.

• Oil exploration in India dates over a century back when drilling of first well begun in 1866 just seven years after the first oil well was drilled in Pennsylvania, USA by Col. Drake (1859).

• The sedimentary basins of India received attention of geoscientists due to increased activities for petroleum exploration since 1950’s.

• There are 26 sedimentary basins in India covering an area of about 3.14 million sq. km, of which 13 are of interest for hydrocarbon exploration based on current status of exploration, knowledge and commercial status.

Chapter 2: Categorization of sedimentary basins

• During the exploration programme of ONGC, erection and refinement of stratigraphy has been carried out continuously from last few decades till date.

• By early seventies it was obvious that a small number of basins alone were producing most of the hydrocarbons in the country and the others had low rate of success.

• Based on the data accumulated on the regional basin wide scale, the petroliferous sedimentary basins were divided into 4 groups or categories (Bhardwaj and Saini, ONGC, Dehradun).

Category I: Basins with Proven commercial productivity:• Cambay basin• Assam shelf• Bombay offshore• Krishna- Godavari basin• Cauvery basin• Assam- Arakan fold belt.• RajasthanCategory II: Basins with Identified prospectivity:• Kutch• Andaman- Nicobar• Mahanadi basinsCategory III: Prospective basins:• Himalayan Foothills• Ganga basin• Vindhyan• Saurashtra• Kerala- Konkan- Lakshwadeep• Bengal

Category IV: Potentially prospective: • Karewa• Spiti- Zanskar• Satpura- South Rewa• Narmada• Deccan Syneclise• Bhima- Kaladgi• Cuddapah• Pranhita- Godavari• Bastar• Chasttisgarh

• In addition, the deep water areas beyond 200 m isobath upto EEZ form a separate category and are considered to be highly prospective. A total of 10, 90,923 sq. km. covering 15 sedimentary basins are under exploration, which is about 35 % of the total sedimentary area available.

1958: Cambay Basin

1967: Rajasthan Basin1889: Assam Shelf

1974: Mumbai Offshore

1980: KG Basin

1973: A&AA FB

1985: Cauvery Basin

Out of 26 Basins 7 are petroliferous

Chapter 4: Hydrocarbon Potential of India

(Source: DGH)

Chapter 6: Production and Consumption of Petroleum (crude) and Natural gas

• The total consumption of petroleum products increased in 2006-

2007 by 5.6% over the previous year.

Chapter 6: Perspective plan of exploration and development for hydrocarbons

• The ONGC and OIL, the two National Oil Companies and a few private and joint venture companies were engaged in exploration and production activities of oil and natural gas in the country. As on 1.4.2007 in public sector, ONGC’s Jurisdiction extended to 339 oil/ gas fields including offshore areas where as OIL was engaged in 19 fields.

• The long-term vision known as India Hydrocarbon Vision 2025 evolved by the Government of India to intensify exploration and enhance hydrocarbon reserves, these includes development of new as well as existing fields, implementation of Enhance Oil Recovery Schemes, recourse to specialized technology, enlisting the services of international experts and encouraging participation of private and joint- venture companies in the exploration programme.

• ONGC Videsh Limited (OVL), a wholly owned subsidiary of ONGC, is pursuing to acquire exploration and production opportunities in Africa, Middle East, Central Asia, Latin America and Southeast Asia.

• In private sector, RIL’s overseas interests include a block each in Yemen and Oman.

Summary• Oil has been mostly generated and accumulated in the

sedimentary rocks, the world over.• There are 26 sedimentary basins in India covering an area of about

3.14 million sq. km. • Basins with Proven commercial productivity are seven viz.

Cambay basins, Bombay offshore, Krishna- Godavari basin, Cauvery basin, Assam shelf, Assam- Arakan fold belt and Rajasthan

• The Bombay offshore basin is the biggest among the proved petroliferous basins of India and is contributing app. About 65% of the domestic production.

• With the increase in technology and exploration work, the category II, III and IV basins may come and join the category I basins.

• With the country importing 70% of its crude oil requirements and to increase the indigenous production, the programme such as India Hydrocarbon Vision 2025 can prove to be fruitful.

References• Bhowmick P.K., Phenerozoic Petroliferous basins of India.,

Glimpses of Geoscience Research in India, pp.1-16.• Bhardwaj V.K. and Saini S.S., Hydrocarbon Potential of India,

Glimpses of Geoscience Research in India. • Indian Mineral Year Book 2007, IBM.• Pandey J. and Dave A., Stratigraphy of Indian Petroliferous

Basins.• Journal of Indian Association of Sedimentologists (1984) 1-66. Umathe R.M., Mineral deposits of India.• Bjorlykke K, Sedimentology and Petroleum Geology.• Einsele G., Sedimentary Basins.