Lithology and Fluid Discrimination Using Bulk Modulus and Mu-Rho Attributes Generated From Extended Elastic Impedance

The introduction of Extended Elastic Impedance (EEI) as a seismic attribute has enhanced the discrimination and prediction of fluid and lithology. Extended elastic impedance (EEI) is an extension of the elastic impedance which allows arbitrarily large positive or negative values of sin^2 by substituting tan for sin^2 where is called chi angle. It is used to approximate several elastic and petrophysical parameters as seismic attributes such as S-impedance, shear modulus, density, porosity, water saturation, mu-rho, bulk modulus and ratio. In this study we generated Extended Elastic Impedance (EEI) through the modification of Zoeppritz equation derived using relations between elastic constants and velocities. The results show that the seismic attributes of the generated extended elastic impedance corresponding to Bulk Modulus (EEI 12) and Mu-Rho EEI (-51). EEI 12 (Bulk Modulus) values are relatively low as expected in a gas zone and EEI -51 (Mu-Rho) values are high as is expected for this reservoir, these two attributes are in turn indicative of fluid and lithology respectively. The extended elastic impedance inversion and their respective horizon slices used in this study provides better characterization of a reservoir by giving maximum discrimination between fluids and lithology.