Abstract

Geophysical reservoir characterization is the bore-hole petrophysically constrained seismic description of the geometry, physical properties distribution and behavior of a petroleum reservoir in order to understand its production history. This investigation demonstrates the utility of a five step procedure to the carbonates of Horseshoe Atoll. First, using horizon based interpretation the amount of anisotropy is estimated between the fast and slow shear waves as well as the amount of anisotropy between the P-wave and the fast shear wave. Secondly, the core and log measurements are integrated in order to identify the controls on the P - and S-impedance response both at log and seismic scale. For the Horseshoe Atoll, it is apparent that the P- and S-impedance dynamically respond to porosity. Third, on the seismic scale one identifies zones of low S- and P-impedance that relate to high porosity zones. Fourth, the anisotropy estimation from P- and S-wave is combined with the impedance results in order to understand production from 50 wells in the area. Fifth, correlation of impedance results to production is best given by the S-impedance. Such a five step geophysical reservoir characterization approach to the Horseshoe Atoll carbonates reveals seismically un-drilled areas which can be exploited for maximizing reservoir performance.