Structural Evolution and Reservoir Control Characteristics of Sichuan Basin

In order to clarify the hydrocarbon accumulation characteristics of continental clastic rock in Sichuan Basin, this paper analyzes the control of regional tectonic evolution characteristics on hydrocarbon accumulation. The research shows that: ① since the basin entered the stage of continental basin, affected by the differential orogeny of Longmen Mountain, Daba Mountain and Micang Mountain, the subsidence center of the basin moved counterclockwise from west Sichuan to northeast Sichuan and then to southwest Sichuan, controlling the distribution of main Source rock of Upper Triassic and Lower Jurassic. ② Continental oil and gas accumulation experienced three key periods of the Late Jurassic, Late Cretaceous and Paleogene, respectively corresponding to the accumulation of Xujiahe Formation in the middle Yanshanian period, large-scale folding in the late Yanshanian period and large-scale filling in the early Himalayan period. The first stage of Xujiahe Formation is the primary migration within the hydrocarbon source formed in the late Jurassic, and the second stage is the secondary migration formed in the late Cretaceous. The first stage of Ziliujing Formation is the primary migration formed in the early Cretaceous, and the second stage is the secondary migration formed in the late Cretaceous Paleogene. Shaximiao Formation formed oil and gas later than Xujiahe Formation and Ziliujing Formation. The first stage is the Late Cretaceous, and the second stage is the Paleogene. ③ The impact of basin differential orogenic activities on the accumulation characteristics of terrestrial strata in the northeastern Sichuan region is mainly manifested in three aspects: structural differences controlling sources, structural evolution controlling traps, and structural activities controlling migration and accumulation. The deep nappe structures and shallow offset structures in the northeastern Sichuan region are favorable accumulation zones for oil and gas, and are also the next exploration targets.