Application of Multichannel Seismic Imaging Methods in the Identification of Faults and Magmatic Intrusions in Southwest Taiwan Basin

The southwest Taiwan Basin is a Cenozoic basin formed on the northern continental margin of the South China Sea, where abundant faults and magmatic intrusions were developed, which is of great significance for the study of oil and gas accumulation and tectonic evolution. In this study, three imaging methods, namely poststack time migration, poststack time migration after dip moveout correction (hereinafter referred to as prestack partial migration) and prestack time migration, were used to image the multichannel seismic data from the southwestern Taiwan Basin, and the recognition effects of these three imaging methods for faults and magmatic intrusions in the southwestern Taiwan Basin were compared and analyzed. Firstly, the method of poststack time migration can identify major faults with large scale, but it is difficult to identify small faults. Secondly, the method of prestack partial migration can identify both large- and small-scale faults, and the number of faults identified by using this method is more than that by using poststack time migration. Thirdly, the method of prestack time migration can not only identify large and small faults, but those smaller faults, and the number of faults identified by using this method is more than that by using prestack partial migration. Poststack time migration can not accurately identify lenticular structural features in magmatic intrusions. Prestack partial migration can identify lenticular blocks of magmatic intrusions. The recognition result of lenticular blocks identified by using prestack time migration is more complete than that by using partial prestack migration. Finally, this study discussed the influence of the maximum migration dip angles on the imaging effect in prestack time migration method, and the effect of multi-channel seismic imaging methods on identifying faults and magmatic intrusions in the southwest basin of Taiwan, which may be helpful to the study of ooil and gas accumulation and tectonic evolution in this area.