Based on the latest seismic data

geological understanding and exploration results in the Southwestern Ordos Basin

paleo-deformation characteristics of the 1st member of the Upper Paleozoic were studied using tectonic evolution analysis and paleo-structure restoration

and controlling effects of paleo-structure on hydrocarbon distribution were analyzed.According to the strata correlation

the sedimentary

deformation

and subsidence characteristics of the 1st member of the Permian Shanxi Formation are identified.The tectonic evolution and hydrocarbon accumulation stages revealed that the key periods of the Upper Paleozoic tectono-hydrocarbon accumulation are the Late Jurassic and the end of the Early Cretaceous in the Southweste.Through the restoration of Shan 1 paleo-structure in different tectonic evolution stages

the ancient structure of the Upper Paleozoic Shan 1 in Late Triassic

Late Jurassic and end of Early Cretaceous share similarities but also demonstrate gradual evolution through time.The paleo-uplift and paleo-slope are widely developed in the late Jurassic

while the western slope gradually narrowed and the Tianhuan Depression is formed at the end of the Early Cretaceous.Based on the analysis of tectonic deformation and hydrocarbon accumulation stages

it is believed that the Late Jurassic Shan 1 paleo-structure is the key factor controlling the distribution of the Upper Paleozoic gas reservoirs in the Southwest Ordos basin.Due to the lack of long-distance migration of the gas in the Upper Paleozoic reservoirs in the study area

the Early Cretaceous hydrocarbon charge is focused around the Late Jurassic ancient structure highs of Shan 1 member.Thus the hydrocarbon accumulation model is characterized by near-source or intra-source accumulation.