Evaluation of petroleum source rocks of Bengal Basin, India

Source potential of Permo-Carboniferous, Mesozoic and Tertiary sedimentary deposits of Bengal Basin has been evaluated to identify the potential source rocks, assess their maturity and amount of hydrocarbon generated/expelled. Nature and maturity of oils are also assessed. Potential source rocks are present in Paleocene and Gondwana sequences in shelf area and also in Miocene, Oligocene and Eocene sections in the hinge A zone and on the east of the platform. In the shelf area, Gondwana and Cretaceous prospects may contain gases generated during 130 to 10 Ma from terrestrial Gondwana source rocks. Although significant hydrocarbon generation has not occurred from the Tertiary sediments in shelf areas due to low maturity, in the hinge zone and on the east of the platform these sediments are mature enough to generate significant hydrocarbon. There is a distinct possibility of better accumulations in Miocene to Paleocene reservoir-trap systems, nearer to areas where Paleogene and younger source rocks are at a maturity of 0.75-0.9% VRo.