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Petrophysical Analysis and 
Evaluation
of Hydrocarbon Potential of the Lower
Cretaceous Sandstone Units in the
Oluseyi Olajide, Petroleum Research Group, Earth Sciences Department, University of the Western Cape, Bellville 7535, Cape Town, South Africa, [email protected]
Obtaining a full detail
of hydrocarbon accumulation is the primary goal of every exploration activity.
A coalesced qualitative and quantitative approach to subsurface studies will
continue to play an indisputable role in enhancing the clearer view of the
hydrocarbon reservoir characteristics.
This study, using Schlumberger Petrel
Modelling system, has explored the hydrocarbon resources of the Lower
Cretaceous sandstone units within the
Low-energy environments generally result in fine-grained deposits of considerable lateral extent. Consequently, shale sections were used to provide the first-pass correlation across the wells. The sandstone and shale sequences have been correlated over a distance of c. 30km across eight wells: E-BA1, E-AR1, E-CA1, E-AA1, E-AD1, E-BB1, E-AO1, and E-AO2. The study interval ranges from 2100m to 3140m (referenced to Kelly Bushing) within the wells.
Electrosequence analysis was carried out to delineate major unconformities within the correlation section. Through the identification and mapping of these unconformities on the correlation panels, a picture of a complete depositional sequence becomes evident. It reveals two primary units of interest, which are the successive mass flow sandstones packages named as BRED-C and BRED-D.
Secondly, detailed petrophysical analyses were carried out for BRED-C and BRED-D reservoirs.
Finally, several realizations of structural
and property models of these reservoirs (BRED-C and BRED-D) were generated by
stochastically integrating quantitatively derived petrophysical properties into
structural models generated through seismic interpretation. The volumes of hydrocarbon
contained in respective reservoirs are estimated using Petrel utility
techniques
.