Evaluation of Seismic Attributes Generated from Extended Elastic Impedance for Lithology and Fluid Discrimination

Seismic attributes are essential in interpretative purposes for accurate discrimination of lithology and fluid especially in areas where the values of acoustic impedance for shale and gas-saturated sands are approximately equal. The extended elastic impedance (EEI) used in this study was generated from a modified Zoeppritz equation which was derived in terms of shear modulus, Psuedo-Poissons ratio, and density. The results show that the two seismic attribute volumes ratio and shear impedance (SI) generated from the extended elastic impedance equation and their respective horizon slices help to show a better characterization of the reservoir and hence, shear impedance (SI) attribute volume and horizon slice shows the determination of the reservoirs lithology and ratio attribute volume and horizon slices predicts its pore-fluid type. The cross-plot of seismic attribute generated facilitated the discrimination of gas sands from brine filled sands as well as the discrimination between sands and shales. The results show that extended elastic impedance (EEI) is worthy effort to highlight the difference between reservoir and non-reservoir to identify hydrocarbon area.