Quantification characterization of the valid natural fractures in the 2nd Xu Member, Xinchang gas field

The natural fracture is a geological phenomenon which is widely distributed in the strata, and plays an important role in the oil & gas development. The fractures effectiveness level is the key to get high oil & gas yielding and enrichment in fractured oil & gas reservoirs. Based on the characteristics and igneous cognition of fractures and all kinds of static and dynamic data in the 2nd Xu Member gas reservoirs in Xinchang gas field in western Sichuan, the parameters such as aperture, permeability and porosity of fractures are interpreted and evaluated. The physical meanings of fracture parameters obtained from different data are clear that laid the foundation of the fracture effectiveness evaluation. Choose the fracture network system of geologic model grid cells near the wellbores for the quantitative characterization effectiveness objects, using the fracture parameters distribution characteristics of the fracture network system, the variables of the parameters distribution characteristics are selected and combined so as to establish the quantitative indicators of fracture effectiveness. Based on the quantitative characterization ideas and the quantitative indicators of fracture effectiveness, the fracture effectiveness and its vertical and horizontal distribution in single well production layer in the 2nd Xu Member gas reservoirs, Xinchang gas field are researched and evaluated. The evaluation results have a good consistency with the regional tectonic, stress field distribution, underground monitoring, production dynamics. Recognize and quantitative methods for effectiveness characterization of natural fractures laid the foundation of the establishment of the effective parameters of fractures and numerical simulation in the geological modeling of fractured reservoirs and also provide direction and ideas for fractured reservoir description and production dynamic research.