Abstract: The Jurassic sedimentary facies in the West Sichuan depression are discussed in this paper. The most favourable hydrocarbon-generating conditions in the study area during the Early Jurassic and early Middle Jurassic consist primarily of perennial lakes and subordinately of seasonal lakes. The organic carbon and organic matter types, organic matter evolution, gas generation rates, coefficients for generation and accumulation, and parameters for volumetric variations are dealt with in detail and reliable results have been obtained. The hydrocarbon production varies between 292483.3 and 333425.0×10⁸m³ for the Jurassic sedimentary rocks, and inferred oil and gas reserves range between 3509.8 and 4001.1×10⁸m³ in terms of organic carbon production and organic microcomponient production in natural gas. This is significant for the study of the Jurassic distant gas accumulation efficiency. Up to now, only about 10% of the total gas reserves are found in the study area. The bulk of future gas will be found and the promise of large discoveries lies also in this area with significant investment in research and development. In these cases, the target areas and prolific areas are both delineated in this study.