The shale gas content of the Longmaxi Formation exhibits significant spatial variation in different structural parts of the Sangzhi area in Hubei Province, reflecting differences in preservation conditions. To quantitatively evaluate these conditions, this study integrates analyses of structural features, fault distribution, formation water chemistry, and shale gas composition from four wells. Results show that preservation is primarily controlled by the F1 and F3 faults. Wells distant from these faults (SY3 and SY5) display weak connectivity with surface water, feature CaCl2-type formation water with high salinity and diagnostic ion coefficients, and contain hydrocarbon gases derived from o... More >