Determination of Reservoir Properties of the Semliki Basin Using Rock Physics Templates

Rock physics plays an important role in reservoir characterization as it links seismic properties to reservoir properties. The Semliki basin is located in the Albertine Graben in the western arm of the East African rift valley. The study demonstrated the application of rock physics modelling whereby two rock physics models were developed namely; Constant Cement model and unconsolidated model. Rock Physics Templates (RPTs) developed by using model parameters to analyse reservoir properties. The four zones identified on the RPT, are interpreted as gas sand, brine sands, shaly sands and shales. The shales indicate decreasing acoustic impedance with increasing Vp/Vs ratio interpreted as laminated shales. To examine the effects of Vp, Vs and impedance, fluid replacement modeling (FRM) was carried out. It was observed that P-wave, density, water saturation, fluid density, fluid modulus, increases on replacing gas with water at all percentages (50% and 100%). However, Swave decreases while bulk modulus matrix, shear modulus matrix and matrix density remained constant. This is because S-wave is insensitive to fluid and the other parameters remain constant because replacing gas with water does not increase the matrix.