Constraining C for fluid properties inversion

Summary Analysis of laboratory measurements of 301 core samples found in the literature for different lithologies, clay content, porosities and pressures was employed to constrain the C constant that accounts for the frame properties of the rock in the AVO inversion method proposed by Batzle et al. (2001). The results showed that C varies for sandstones between 2 and 2.9 and for carbonates between 2.5 and 3.5. If clay content increases C decreases, and if cementation (carbonates) and porosity increases C increases. We applied this method to a small 3D seismic volume corresponding to the King Kong field in Gulf of Mexico in order to estimate the fluid properties of the reservoir (gas sandstones) and the water bearing sandstones. Specifically we used this method to estimate the fluid term, which is composed by density of the rock and the fluid bulk modulus (ρKf). The results successfully discriminate two pay sands intervals from the background; however absolute values of fluid bulk modulus are not comparable to the results yield by well-log data available of the prospect. Probable causes are tuning effect and calibration of seismic amplitudes with well-log data.