Abstract: Tectonic Evolution and Petroleum Geology of Bombay Offshore Basin, India

PARIDA, G, A.K. GHOSHAL, M.M. JAIN, P.L. ZUTSHI

Two sets of intercrustal extensional faults and the Paleogene hinge form the basic structural style of Bombay Offshore divergent passive continental margin basin, initiated by rifting of Seychelles and India during Late Cretaceous period. Six major Cenozoic depositional sequences constitute four lithoenvironmental facies. Four evolutionary stages in two major phases, `early rift' phase (`narrow rift-valley' stage and `protoceanic' stage), and `post-rift' phase (`shallow marine platform' stage and `open marine' stage) are recognized in the basin.

The petroleum systems have been outlined. Eocene neritic shale and Oligocene prodelta / slope shale form two principal source rocks. Middle Eocene ramp carbonate, Oligocene deltaic sandstone and Early Miocene shelf carbonate-basinal turbidites-slope fans form the major reservoirs. Two types of structural traps, one basement related and the other inversion tectonic related, and two different sets of stratigraphic traps, one in the form of wedgeout and the other in turbidites and slope fans, have been recognized.

The study identifies Middle Eocene ramp carbonate over synthetic transfer zones in homocline, and Middle Eocene ramp carbonates in structural traps and Early Miocene basinal turbidites - slope fans forming stratigraphic traps in depressional morphotectonic unit, as potential targets for future exploration in the basin.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria