Evolution and forming mechanism of hydrocarbon reservoir of Nanbaxian structure in north edge of Qaidam basin

Nanbaxian structure is a tertiary structure in the north edge of Qaidam basin,which has experienced five local structure evolution stages as the early and middle Jurassic faulted depression,the late Jurassic-Cretaceous extrusion,the Palaeocene-Miocene extension subsidence,the Pliocene(Youshashan period) regional extrusion,the late Pliocene(Shizigou period)-Quaternary extrusion and the thrust and partly slip,and is subject to Phase Ⅰ and Phase Ⅲ of Hima-layan movement,resulting in two different tectonic patterns as the basement-involved in the south and the mantle de-tachment in the north.The movement of fault in the south gives rise to the native reservoir in Tertiary,playing a role of migration path,while The movement of fault in the North plays the role of reformation of the native reservoir and led to the secondary hydrocarbon reservoir of the upper Tertiary.