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The South Yellow Sea is a superimposed basin overlying Mesozoic-Cenozoic continental sediments, which in turn overlie Paleozoic-Mesozoic marine deposits that are now the target of hydrocarbon exploration. Strongly modified by multiple tectonic events, the marine sediments feature a large tectonic relief, with obvious horizontal anisotropy in seismic velocity, which significantly affects the seismic image quality. In this study, the sedimentary velocity anisotropy and its influence on image quality were analyzed using an analytical theory method, assuming transversely isotropic medium with vertical axis of symmetry (VTI), and using seismic and well-log data. Additionally, an anisotropic prestack time migration was used for the imaging of the field data. The results showed that the anisotropic pre-stack time migration processing could be used to significantly improve the accuracy of the seismic images in areas with distinct faults, offering clear images of accurately located fault planes and fault edges, thereby improving the lateral resolution of the seismic data and its signal-to-noise ratio.

Summary The near-surface conditions of the Fushan sag are very complicated and the topographical relief is drastic. The lateral variation in thickness and the speed of weathering is intense and igneous rocks crop out. This results in a severely distorted time-distance curve, an unstable refraction layer, great changes in the shape of the record, a serious problem of non-surface-consistent statics, and rendering the conventional statics method unsuitable. All of these make the static correction of this area very difficult to solve. In this article we put forward an integrated statics approach including a tomographic inversion static correction based on uphole and marked layer, interactive layered and segmented first arrival static correction, global optimization reflection residual static correction and non-surface consistent static correction. A good result is achieved by using these methods, suggesting that our methods are feasible.