Abstract: There is huge gas resource potential in the continental facies clastic reservoir of Xujiahe Formation in Upper Triassic of Sichuan Basin. In recent years, commercial gas flow has been got in central Sichuan, such as Hechuan and Guang'an etc. In the study area, Xujiahe gas reservoir is mainly lithologic gas reservoir and compound traps of lithologic-structural gas reservoir. The reservoirs are very heterogeneous horizontally and vertically, and most of them are thin interbedding with low porosity and low permeability. Moreover, the reservoir fluid contents are very complex, so it is very difficult to perform reservoir prediction and fluid detection. Aimed at this type of lithologic gas reservoir, prestack high-fidelity processing technique has been applied to obtain prestack gathers with high quality, then, prestack quantitative reservoir prediction technique, mainly including elastic parameter inversion, as well as hydrocarbon detection technique which integrates elastic multi-parameter method and expanded elastic impedance inversion have been applied to improve the accuracy of reservoir prediction and fluid detection, and good application effects have been achieved

Key words: Sichuan Basin, central Sichuan, Xujiahe Formation, low porosity and low permeability, prestack seismic technique