Abstract:
The need to improve the physical understanding of seismic information through rock
physics which provides a way of relating elastic properties such as the Primary Velocity
(Vp), Secondary Velocity (Vs), Acoustic Impedance (AI), LambdaRho (λρ), MuRho (μρ),
and Bulk Modulus (K) to measured physical properties within reservoirs is a core focus for
higher exploration success rates and improved oil recovery. The data-base for this study
consists of 3-D seismic data, checkshot data, suite of wire-line logs comprising; gamma
ray logs, resistivity logs, and sonic logs. Well correlation across five (5) wells was carried
out to show the continuity of a reservoir. Petrophysical analysis was done to generate
parameters such as; Total Porosity, Effective Porosity, Permeability, Volume of shale,
Formation factor, Hydrocarbon saturation and Water saturation for two (2) reservoirs. The
reservoir is fault assisted with 46 faults and two (2) horizons mapped across the seismic
sections, also structural maps (Time and Depth maps) and property models were generated.
Rock physics analysis was carried out to correlate the result of petrophysical analysis and
seismic interpretation and modeling. The Rock physics analysis includes Rock physics
crossplot of elastic parameters against calculated reservoir parameter (e.g. Vp against
Porosity to test for the degree of cementation of the formation, Vp against Vs to delineate
lithology, LambdaRho against MuRho for identification of fluid content) and Gassmann
fluid substitution for Porosity prediction. The result shows Porosity ranging from 26.7 %
to 33.6 % for Petrophysical analysis, 27.4 % to 30.2 % for Gassmann Fluid Substitution
and 15% to 40% for the modeled Porosity. This indicates a good to very good porosity
rating for the reservoirs. Therefore, the Gassmann Fluid Substitution porosity result has
been able to validate the results of the petrophysical parameters and that of the models.
