Source-reservoir rock assemblages and hydrocarbon accumulation models in the Middle-Lower Jurassic of eastern Sichuan Basin, China

The eastern Sichuan Basin in China holds vast potential for oil and gas exploration the Lower-Middle Jurassic strata. However, geological characteristics hydrocarbon accumulation patterns of this region remain largely unclear. During deposition period strata, is characterized by formation multiple sets source, reservoir, caprock assemblages through depositing lake-delta-fluvial deposits, which have great potential. source rocks are mainly developed Dongyuemiao Member, Da’anzhai Liangshan Formation. These a total organic carbon (TOC) content greater than 1 varying range matter maturity, with Ro value 0.8–2.0. kerogen these primarily type II, smaller proportion being III. A reservoir can be found strata Sichuan, sandstone reservoirs predominantly Formation, Shaximiao Zhenzhuchong Member. Shale mostly present Dongyuemiao, Da’anzhai, Liangshan, Maanshan Members, there limited distribution limestone Member arrangement has led to three types reservoir-forming combinations, including lower generation upper storage, self-generation self-storage, composite. Sandstone typically shale should prioritize “layer area selections.” primary targets, semi-deep lake deposits syncline most favorable. degree fracture development also significant impact on content. Formation serve as secondary anticline areas that better sealing conditions more Limestone distribution, high steep fractures relatively advantageous.