Abstract: Proterozoic Petroleum Systems of Indian Sedimentary Basins: A Perspective

PADHY, P.K

Presence of Petroleum fairways in the Proterozoic sequence has in recent past added a new target for exploration, albeit riddled with high risk, in India. The Proterozoic basins namely Vindhyan, Cuddapah, Chattisgarh, Bastar, Kaldgi and Bhima are classified as interior cratonic basins. These basins are tectonically associated with Proterozoic mobile belt, and they evolved due to crustal downwarping. Non-commercial surface flow of wet gas from sediments of Riphean age has been established from Vindhyan basin. Heavy oil accumulation in Proterozoic clastics has been proved in Bikaner-Nagaur peripheral foreland basin in the northwestern part of Indian shield.

The rock assemblages of these basins are characterized by conglomerate-mature clastic-carbonate-shale suites. Presence of tide-dominated eperic sea during Proterozoic in Indian plate has been documented. The biogenic remains, amorphous organic matter, algal filaments associated with Proterozoic strata might have generated hydrocarbons. Siliciclastics and carbonates constitute important reservoir facies. The trap style is mainly basement-controlled structures. Stratigraphic traps associated with unconformities are some of the other locales for hydrocarbon exploration. The capping mechanism is generally transformational in nature.

Potential of these plays is yet to be explored in Indian sedimentary basins. Integrated basin analysis of interior sags, peripheral foreland basins and Pakhal Group of Pranhita-Godavari rift may optimistically unravel, though in restricted scale, the prevalence of Proterozoic petroleum systems.

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