Abstract

Fluid Replacement modeling is a significant tool as it enables to predict the elastic response of the rock, when the fluid filled in its pores changes from one type to another. In this paper, a sand of Mid Miocene age inferred as water bearing in one well is chosen for Fluid replacement modeling using Biot-Gassmann fluid substitution method. The changed petrophysical properties are determined to simulate the sonic and shear sonic response after Fluid Replacement Modeling(FRM). The log crossplots of P-impedance versus Vp/Vs ratio before and after FRM are used to characterize the reservoir. Pre-Stack seismic data was inverted for P-impedance and S-impedance and the results of Pre-Stack simultaneous inversion are first calibrated for in-situ conditions by keeping the FRM well as blind well. From the cross plot interpretation, the results are directly projected onto the inverted volume itself to find the probable hydrocarbon bearing locales for the sand.