Research and application of coal seam interference trimming in seismic reservoir prediction of K Gas Field in Xihu Sag

The strong reflection caused by coal seam has strong interference effect on seismic signal. The K Gas Field in Xihu Sag of the East China Sea Shelf Basin features poor continuity, scattered distribution, and thin thickness. In this study, we found that the presence of coal seams could lead to problems in sand body prediction, such as creating something out of nothing and shielding of seismic reflection structures, which severely limited the accuracy of seismic reservoir prediction. Therefore, by using semi-quantitative interpretation of geophysical responses to locate coal seams, seismic high-amplitude filtering to filter coal seams, and multi-wavelet decomposition and reconstruction to replace coal seams, the influence of strong reflection from coal seam in K Gas Field on seismic signal was removed while retaining as much effective seismic reflection information as possible. After eliminating strong reflection of coal seams, the correlation between seismic data and reservoir became higher, and the accuracy and reliability of reservoir prediction were improved.