New Face of Deepwater Kerala, India: Ground for Elephant Hunting

Nathaniel Duggirala, Ravi Bastia, Ravi Verma, Srinivas Tenepalli, and Kenneth D'Silva
Geology & Geophysics, Reliance (E&P) Petroleum Business, Navi Mumbai, India

Indian deepwater exploratory efforts are propelled into new heights subsequent to the discovery of world-class Dhirubhai Gas Field in 2002. Exploration thus followed in the eastern deepwater basins evinced great optimism, while as the same in western deepwater generated pessimism resulting into a near cease of exploratory activity. As majority of petroleum provinces of India are associated with failed-rifts, “What’s Next” for western deepwater ought to involve identification of such opportunities in the realm of plate tectonics.

The episodic breakup of the Eastern Gondwana during the period of Triassic to Cretaceous facilitated megaregional rift-drift structural superpositions in the southern tip of India i.e., deepwater Kerala basin. Plate tectonic reconstruction of Middle Jurassic to Early Cretaceous demonstrates the basin as situated on north-eastern part of Proto-Mozambique Ocean. Antarctica, Madagascar and Africa were the major provenance of sediment supply under favorable climatic conditions for organic productivity. A synthesis of regional seismics, gravity and crustal-scale EM-conductance anomaly, seismic velocity and magnetics indicate that the southern tip of India as a triple junction with coast parallel and coast transverse extensional/shear type fault/fracture zone systems. Structuration in the study area is controlled by Vishnu Fracture Zone (VFZ), a N-S trending regional tectonic element identified on gravity in conjunction with regional ocean floor magnetic anomaly map. Long offset seismic characterization of VFZ indicate it as a transform fault responsible for structural inversion of the pre-existing rift-graben architecture. Large scale geological structures are identified on the eastern flank of the VFZ, wherein adequate heat-flux and vertical migratory pathways are expected to facilitate the hydrocarbon generation-migration-entrapment paradigm.

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