Exploration of Raghavapuram Petroleum System (!): An Enigma or a Point to Cogitate ?

By

 Sushma Rawat¹, Kaushalendra B. Trivedi²

(1) Dy.S.G.,Oil & Natural Gas Corporation Ltd.,India, Dehradun-248195, India (2) Oil & Natural Gas Corporation Ltd,India, Dehradun, India

 Krishna- Godavari basin is conspicuous and decipherable by a bite on North-East aligned passive continental margin of Indian peninsula. The structural grain is aligned parallel to this trend and owes its origin to rift-drift phenomenon of Indian plate from Gondwanaland and the arcuate shape fits well and explicitly explained by Smith & Hallam fit (1970). Seven Petroleum systems ranging from Triassic to Mio-Pliocene are being probed & are under exploitation in this basin. Out of these, the Raghavapuram Petroleum system (.) of Early Cretaceous age is the most enigmatic and by an estimate around 17 MMt (O+OEG) in place hydrocarbon still remains untapped in this play alone. Till date a total Of 23 well’s have been explicitly targeted for exploring this play out of which 5 met with success in form of gaseous and liquid hydrocarbon strikes, the number does not include serendipity. Subsequent delineation of specific prospect has not yielded positive results, as the reservoir facies encountered in a well could not be traced in next well. This adds to the enigma of hydrocarbon hunt in Raghavapuram petroleum system (.). A sequence stratigraphic approach to the problem was adopted, aimed at establishing a spatial process response model based on well data, electrologs, seismic investigations (2350 LKm) and Stratotype studies. This has clarified the relationship of stratal stacking patterns and facies to their controlling variables, accommodation space and sediment supply. By the comprehensive Sequence stratigraphic studies authors have conceived a model to mitigate the exploration and delineation problems for Raghavapuram Petroleum system and identified possible locales for better reservoir development which will lead to comprehensive understanding for exploration and exploitation of this hitherto enigmatic play of Krishna-Godavari basin.