The Rock Physics Research Of Typcal Tight Clastic Reservoir In Western Sichuan

The focus has been transferred from shallow-middle Jurassic gas reservoir to the deep tight or super tight clastic reservoir in western Sichuan. It has great exploration potential in deep reservoir. However, due to the geological conditions are very complex in the deep fractured tight clastic reservoir, the risky of exploration is very great. At present, it is the major problems that the reservoir prediction, identification of lithology and fluid identification urgent need to solve. The geophysical methods of logging and seismic inversion is the main way to predicted the effective reservoir. Rock physics is the bridge to contact the log and seismic properties of reservoir parameter prediction, and the main means on inversion and interpretation of seismic data. We must increase the intensity of rock physics research to improve the success rate of deep exploration, and support the development of the 10 billion gas field for Southwest Oil & Gas Field Company.In view of actual demand from the Xujiahe formation of the tight or super tight clastic reservoir in XC region, based on the research of scholars at home and abroad, acquire the accurate mineral content and reservoir parameters with logging, geological and logging information. The means is to do regression analysis and get the formula using elements capture logging (ECS) and conventional logging. The means provide high-quality data for prediction of the shear wave and rock physics modeling.Meanwhile, we computed the shear wave velocity using the effective medium theory, empirical formula and seven kinds of wave forecast model based on the mineral content and reservoir parameters. And compared with measured wave velocity data to analysis the applicable conditions and accuracy of the forecast model.In order to obtain shear wave information in different fluid-saturated rocks ,the formula introduced by Gassmann for fluid replacement is used. Then, we calculate the elastic impedance using different angles and logging data, based on the pseudo-impedance inversion theory introduced by Connolly, Mukerji, et. On fluid replacement and analysis of reservoir parameters, the rock physics model is established and used in the reservoir lithology and fluid identification in Xujiahe formation. In reservoir lithology and fluid identification, the elastic impedance play a decisive role. It increases the success rates to identify the lithology and fluid.