Seismic rock physics analysis of tight sandstone and optimization of reservoir prediction methods in the Sichuan Basin
The lithology of the second member of the Xujiahe Formation in the HC block of the Sichuan Basin is mainly composed of lithic feldspar sandstone and feldspar lithic sandstone.It has the characteristics of tight sandstone reservoir with low porosity and low permeability,great changes in reservoir physical properties,and overlayed p-wave impedance.Reservoir prediction based on the post-stack inversion method has strong multi-solution.In order to reduce exploration risks and improve the success rate of well location deployment,seismic rock physics interpretation charts were established using a Raymer layered model based on seismic rock physics analysis techniques.Pore fluid displacement was carried out using the Gassmann equation,and AVO forward attribute analysis was performed using the displacement results.According to the above-detailed analysis,the AVO type of the upper surface of the gas-bearing reservoir of the second member of the Xujiahe Formation is Class Ⅳ.Af-fected by lithology and physical properties,pore fluid changes do not cause the change of AVO type.At the same time,the two parameters of p-wave velocity ratio and p-wave impedance are defined as sensitive elastic parameters of the reservoir,and the reservoir prediction method is optimized.The research results of this paper predict the thickness distribution of tight sand-stone gas reservoir in the second member of Xujiahe Formation in the HC block of the Sichuan Basin,and submit two well loca-tions.The predicted results are in good agreement with the actual drilling data.This method has been widely used in tight sandstone reservoirs with similar geological conditions.
万方数据
维普
