Karst reservoirs seismic prediction of Lower Permian Maokou Formation in central Sichuan Basin, SW China

Based on the new well logging and seismic data of recent years in central Sichuan Basin, the comprehensive study of the karst reservoirs in the Lower Permian Maokou Formation was carried out using new geophysical technology. The quantitative rock physical modeling and analysis demonstrated that the velocity and density of the reservoir decrease with the increase of porosity, shale volume and gas saturation. Seismic forward modeling analysis based on rock physical modeling confirmed that the reflection characteristics of the karst reservoirs show 'dim point' at top of the Maokou Formation, which is weak amplitude and low frequency. Through seismic attributes and acoustic impedance inversion, four large areas of favorable karst reservoirs are predicted. Based on the comprehensive evaluation, it is thought that karst lithologic reservoirs in up-dip direction can be formed, and the west to Shehong and Yanting are the most favorable exploration areas in the central Sichuan Basin.