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.