Estimation Of Gas Hydrate Saturation Using Model Based Acoustic Impedance Inversion From Mahanadi Offshore Basin

The bottom simulating reflector (BSR), observed on seismic section in the Mahanadi offshore basin indicates the presence of gas hydrates. Gas hydrate saturation is estimated from electrical resistivity log based on Archie's empirical relation and/or from sonic velocity log using rock physics modeling approach at the vertical log position. The lateral and vertical extent of gas hydrates saturation over a larger area is obtained by post-stack impedance inversion of seismic data constrained by well log data. The inverted velocity coupled with rock physics modeling provides the estimation of gas hydrate saturation. The present study suggests that average gas hydrate saturation along a seismic line passing through site NGHP-01-19 in the Mahanadi Basin is about 3%. Gas hydrate saturation directly measured from the pressure cores, is found to be 2.4% at site NGHP-01-19, showing close correspondence with the estimation.