Publications

While the multi-component P-S seismic data can provide superior structural images compared to the conventional P-P data below the gas clouds, the AVO (Amplitude Versus Offset) characteristics of such P-S data is also shown to be very useful for detailed reservoir characterization and fluid discriminations. A successful 3D OBC multi-component wide azimuth seismic was recently acquired on Bekapai field in Mahakam delta and the resulted P-S data provided significantly improved structural image of the subsurface below the shallow gas pockets. Moreover, given the very good quality of P-S seismic image on Bekapai, a methodology is investigated for further exploiting the P-S amplitudes and more specifically to analyze the possibility of using the AVO response of acquired P-S data for further reservoir characterization and seismic fluid discrimination on the field. Synthetic seismograms are modeled in order to understand the AVO behavior of P-S seismic for different lithologies and reservoir fluid contents on Bekapai. A methodology is then implemented to compute AVO lithofacies attributes from the modeled P-S seismograms. The modeling results show that the methodology works and the computed attribute can be used for detection of gas sands. Indeed, the P-S AVO response can be exploited and be used as a tool to detect the density variation. Given that the P-S reflectivity is related to density contrast, when density changes are appreciable as saturation changes the computed P-S AVO attribute can discriminate the gas sands from water sands. In the second phase, the methodology is applied on Bekapai data in order to compute a 3D AVO lithofacies cube from the acquired P-S angle stacks on the field.