Processing strategy for deep imaging beneath complex shallow structures under shallow water: a case study in the Enping Sag

Abstract As offshore exploration targets deeper parts of shallow-water areas in the eastern South China Sea, an increasing number of hydrocarbon discoveries have been made in recent years, and the difficulty of such exploration has increased. One such challenge lies in mid-depth imaging beneath complex shallow geological structures. When a seismic wave penetrates groups of densely distributed fractures and/or volcanic rocks, only a fraction of the energy reaches the target depth. As the ray path becomes complex, the middle-to-deep imaging quality becomes significantly poorer. In this study we applied three techniques: 3D joint source and receiver deghosting and zero phasing, dynamic resolution time-lag full waveform inversion, and least-squares Q-compensated Kirchhoff pre-stack depth migration, to improve the related seismic data and ultimately improve the imaging quality beneath complex shallow geological structures in the shallow-water environment of the eastern South China Sea, providing better subsurface understanding for the exploration of this area.