--> Abstract: Source Rocks in Deep Water Depositional System in East and West Coasts of India, by Dinesh K. Pande, Ram Raj Singh, and Kuldeep Chandra; #90078 (2008)

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Source Rocks in Deep Water Depositional System in East and West Coasts of India

Dinesh K. Pande, Ram Raj Singh, and Kuldeep Chandra
ONGC, Dehradun, India

The deep water areas of India (beyond 400m isobaths) cover about 43% (1.3 million sq.km) of the total sedimentary area of the country. ONGC has undertaken the biggest-ever deep water exploration campaign towards East and West coasts of India globally by a single operator and has made the first ultra-deepwater discovery at the water depth of 2841m in the country.

The Western offshore deep water area (2,20,000 Sq. Km) stretches from northern most Kutch-Saurashtra to Southern most Kerala-Konkan sub-basins. Ten wells have been drilled in deep water (bathymetry 1074 to 3008m) penetrating tertiary sedimentary thickness ranging from 872 to 4331m. The source rock development seems to be poor in tertiary for the drilled deep water locations of western offshore area as revealed by source rock analyses.

Mahanadi Basin in Eastern offshore extends over an area of 141,589 sq. km. Six wells have been drilled in the bathymetry ranging between 795m to 1088m and have encountered sedimentary thickness between 1035m to 2298m. Thin source sequence having fair source potential of Plio-Miocene age has been identified in one well. One of the wells has flowed gas at the rate of 2,10,000M3 per day which is of biogenic origin as revealed by carbon isotopic studies. This discovery opens the seventh basin successfully proved by ONGC. Fourteen wells have been drilled in five deepwater NELP blocks in N-E part of KG basin covering shelf, slope and deepwater regime (bathymetry 50m-3000m). The total sedimentary thickness is around 10,000m in basinal lows. Good to excellent potential source rocks are observed in Paleocene and Cretaceous sediments in two wells. Significant gas discoveries of biogenic origin were made in Pliocene formation in a few wells. The deep water areas specially eastern offshore of India hold promise for significant hydrocarbon discoveries in near future.

 

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas