Seismic prediction of weathering crust palaeokarst reservoir: a study on the karst reservoir of the 4^th Leikoupo Formation of Yuanba area in Northeast Sichuan

The karst reservoir of the 4^th Leikoupo Formation of Yuanba area in Northeast Sichuan has the deep buried depth and the strong heterogeneity character, conventional seismic reservoir prediction method is difficult to explain the distribution of reservoir development, and the prediction of distribution of reservoir is an important exploration difficulty. Yuanba area is located in the karst paleogeomorphology karst slope area, the landscape control the karst reservoir distribution, the karst monadnock in high slope is most beneficial to form karst reservoiration, and the aluminum shale in the top of the karst monadnock is conducive to the preservation of gas reservoir. In this paper, the " Impression method", seismic reflection structure analysis in the study area are integrated to make 3D seismic paleogeomorphology by using the oil and gas detection technology analysis, based on the time frequency analysis, finally a complete set of paleokarst reservoir prediction method was formed, thereby reducing the risk of exploration.