Preservation condition differences in Jiaoshiba area, Fuling,Sichuan Basin

The preservation condition is critical to the enrichment and high yields of shale gas. Exploration and development of the Fuling shale gas indicated that the preservation condition changes horizontally in the Jiaoshiba area. This change was analyzed using core observations, FMI logging interpretations and comprehensive seismic interpretations. Different transformations of structure units after later tectonic movements explained the diversity of preservation condition. Specifically, the differences are related to fracture scale, closure, the effect of fracture superposition and the formation deformation. The size of the fault (fault distance, extension length, offset, fracture density) and the fault properties determine the basic preservation condition of structural units. The sharp angle relationship between the maximum principal stress and the direction of the fracture affects the sealing of the fracture. The larger the sharp angle, the better the sealing property. The vertical and lateral superposition of the fracture system will form a three-dimensional seepage channel, which has a great influence on the original closed environment of shale gas, and causes strong dispersion of shale gas. This causality is worthy of attention. At the same time, the dip angle of the formation is a direct reflection of the extent of the tectonic movement. As the diffusion effect in the parallel stratification direction of shale gas increases with the inclination angle, which increases gradually, it is necessary to analyze the dip angle when choosing the prime target especially in complex structural areas.