Post stack inversion for reservoir characterization of KG basin associated with gas hydrate prospects

Post–stack inversion transforms a single seismic data volume into acoustic impedance through integration of seismic data and well data. Benefits of acoustic impedance obtained after inversion are well established for stratigraphic interpretation in comparison to conventional seismic data analysis. Model based and band limited post stack seismic inversion are carried out with a 2D seismic data to derive the stratigraphic information. The methodology of inversion includes statistical analysis of log derived acoustic impedance with P-wave velocity, density and spectral analysis of seismic data, wavelet estimation, seismic to well tie, generation of initial 2-D geological model. Use of model based inversion scheme and band limited inversion has validated inverted impedance results. Present study is based on data from Krishna Godavari basin of India. Model based and band limited inversion results have helped in delineating the stratigraphic prospect in the study area. This study demonstrates the effectiveness of using acoustic impedance volume for performing stratigraphic interpretation and reservoir characterization. From this study, it is noticed that near vertical reflection two way time 250 ms to 350 ms with CDP 630-700 have high acoustic impedance contrast, which can be interpreted as potential gas hydrate saturated zone.