Natural Gas Geochemistry of Jurassic Shaximiao Formation in the Western Sichuan Basin, China: Fault-Controlled Differentiation in Accumulation Process

The Jurassic Shaximiao Formation in western Sichuan has made significant contributions to the natural gas reserves and production of China, with many fields successively discovered. accumulation evolution progress discrepant gathering law are continuously improved constantly deepened exploration development. In order find evidence for difference method reshape migration their dynamic processes based on time space, this study analyzes process Middle reservoir Zhongjiang field using geochemical parameters, including conventional composition gas, light hydrocarbon components, carbon isotope, formation water, more than 160 samples from 155 wells. results show that gas-filling period, patterns, phase state, etc., closely related distance between source faults. geochemistry tracer parameters water reveal abundant information about process. Sha-3 reservoir, featuring a two-period supply, two i.e., seepage diffusion, dominated by water-soluble phase. Similarly, Sha-2 late single same miscible free main pattern Sha-1 which features is seepage, From lower part Sand-3 upper exhibits trend where early–late continuous filling turns into filling, lateral oil becomes shorter gradually, gas-rich range decreases gradually. can provide valuable reference reservoirs controlled faults river sand bodies.