A Surface Geochemical Survey over Part of the Pranhita-Godavari Basin and its Impact on the Hydrocarbon Prospects of the Basin

The Pranhita-Godavari Basin is a large intercratonic Gondwana Basin located in the eastern part of Peninsular India. It essentially represents a NW-SE trending failed rift and is separated into three sub-basins, viz. Godavari, Kothagudem and Chintalapudi sub-basins, by transverse transfer zones. Though a number of sizeable coalfields are located within the basin, it is essentially unexplored from hydrocarbon point of view. Hydrocarbon source-rock analyses carried out on samples from outcrops and shallow bore-holes (60 m-500 m depths) show low to moderate maturity. In order to investigate the hydrocarbon potential of the basin, a reconnaissance surface geochemical survey was carried out over an approximately 5000 sq km area covering most of the Godavari sub-basin, which is the largest of the three. The results of the study indicate that the basin (within the area of the survey) is actively leaking measurable quantities of light hydrocarbons to the surface and that all the anomalies are full spectrum anomalies of petrogenic origin. Three regions of significant anomalies can be outlined; one is a gas-prone trend whilst two are oil and gas-prone.