The extended elastic impedance (EEI) method is known as a reliable method for fluid prediction and lithologic estimation in the interpretation phase of seismic data. Compared with the conventional elastic method, the EEI method using 180-degree angle of rotation in acoustic impedance under certain approximations is able to estimate elastic parameters such as shear wave impedance, P to S-wave ratio, bulk modulus, shear modulus, and Poisson ratio more accurately
An important issue with this method is the sensitivity of this method to petrophysical parameters and the high ability of this method to convert seismic information to petrophysical parameters. Since only shear wave information was available in one well, we validated the results using P-wave estimation with this method and found that the results have high accuracy as a secondary variable for estimating petrophysical parameters.