Dual-Wave Advantage: PP-PS Pre-Stack Inversion for Complex Reservoir Characterization

Summary The integration of P-wave (PP) and converted S-wave (PS) data through pre-stack simultaneous inversion provides a transformative approach to reservoir characterization in shallow gas-affected fields. This study demonstrates how PP-PS joint inversion enhances subsurface imaging by leveraging shear impedance constraints, mitigating the density-velocity trade-offs inherent in PP inversion alone. Using ocean-bottom cable (OBC) seismic data from a gas-masked field in the Peninsular Malay Basin, this research implements a two-stage event registration process, guided by a laterally and vertically varying Vp/Vs ratio cube, to achieve precise PP-PS alignment. The inversion workflow integrates well-to-seismic calibration, wavelet extraction, and Knott-Zoeppritz approximations to refine inversion accuracy and reduce uncertainties. Results confirm that PP-PS joint inversion significantly improves porosity prediction, hydrocarbon identification, and reservoir modeling, overcoming gas cloud imaging challenges. This study establishes PP-PS inversion as a critical tool for de-risking exploration and enhancing reservoir assessments in complex geological settings.