TTI Medium Anisotropic Reverse Time Migration Imaging and Its Application in Oil and Gas Exploration in the Xihu Depression of the East China Sea

The East China Sea Shelf Basin, especially the Xihu depression in its northeastern region, has long been regarded as an important target area for oil and gas exploration in China. Since the development of the late Cretaceous, this region has experienced complex and multistage tectonic movements, such as extensional faulting and compressional inversion, forming its current unique geological structure pattern. As one of the largest Mesozoic–Cenozoic sedimentary basins offshore China, the East China Sea Shelf Basin not only contains abundant oil and gas resources but also occupies a key strategic position. In addition, it is gradually becoming an important base and strategic core area for China’s oil and gas resource development. Although remarkable progress has been achieved in oil and gas exploration, seismic exploration in the Xihu depression still faces many challenges. Especially in deep target layers, weak seismic reflection energy, low signal-to-noise ratio, and poor wave group continuity seriously affect the efficiency and accuracy of oil and gas exploration. In addition, given the considerable influence of folds and faults in the East China Sea Xihu Basin, transverse anisotropy is widespread, which causes difficulty for conventional imaging technologies based on isotropic assumptions to achieve accurate imaging. Therefore, to address these challenges and meet the need for accurate imaging of complex structures in the Xihu depression of the East China Sea Basin, it is essential to advance research on anisotropic imaging technologies. This study responds to that need by integrating the reverse time migration method under a tilted transversely isotropic (TTI) medium model and applying it to the imaging of the Xihu depression. The imaging profiles based on the TTI medium can substantially improve the imaging accuracy and signal-to-noise ratio, effectively improve the imaging quality of the fault systems and mid-deep strata in the area, and provide new technical support and progress momentum for oil and gas exploration in the Xihu depression of the East China Sea.