Research on main controlling factors of tight sandstone gas accumulation in coal-bearing strata in the southern North China Basin: Comparison with the Ordos Basin

Tight sandstone gas (TSG) reservoirs develop extensively in the upper Paleozoic coal bearing strata both southern North China Basin and Ordos Basin. The former has not achieved important advances TSG exploration, while latter built largest production facility China. By comparing accumulation conditions Tongxu area of Fuxian Basin, main controlling factors were analyzed this article. results indicate that organic matter type source rocks are mainly III kerogen, vitrinite reflectance values (Ro) greater than 3.1%, over mature, reservoir characterized by low porosity extra permeability; therefore forming similar to those During Late Jurassic-Early Cretaceous period, after a large-scale generation hydrocarbons from two basins, tectonic movements Yanshan period controlled differential TSG. been uplifted as whole processes since Triassic, which allowed continuous deposition Triassic strata, thus providing good sealing for reservoirs. experienced multi-stage compressive extensive actions, so original unified basin was divided into several residual blocks. However, thickness slopes sags is higher. rocks, caprocks, overlying continuously deposited time, time allocation elements favorable. Therefore, conducive preservation Paleozoic. Such defined high saturation enriched gas.