Seismic processing for coal-rich Pinghu reservoirs in the slope zone of the Xihu sag

Thin coal seams in the Pinghu Formation, Pingbei slope zone of the Xihu sag, cause strong seismic reflections and geologic misinterpretation. These strong reflections have a remarkable negative impact on reservoir prediction, including lateral extension and vertical thickness prediction, through seismic inversion. Based on different reflection coefficients of coal-mud-sand associations, we propose an angle-gather conditioning technique to identify and eliminate strong reflections and thus weaken the effect of coal seams. Gather conditioning suppresses strong reflections of coal seams and side lobes and highlights effective signals of sandstone reservoirs. A prestack inversion shows improved reservoir prediction with decreased uncertainties, which offers support to development well drilling and post-drilling evaluation of the Pinghu Formation in the slope zone.