Marine basin reformations and accumulation factors in Lower Yangtze region

The Paleozoic marine basins in the Lower Yangtze region have experienced 3 stages of tectonic movements since the late Mesozoic including face-to-face compression from the late Indosinian to the early Yan-shanian, sinistral strike slip from the middle to the late Yanshanian, and detachment during the Himalayan period, which made the occurrence and geologic structure of marine basins very complicated. In accordance with the tectonic movements, hydrocarbon generation and accumulation in the marine basins in the Lower Yangtze region also went through 3 periods including initial hydrocarbon generation and early accumulation from Caledonian to the early Indosinian, destruction and adjustment from the late Indosinian to Yanshanian, and secondary hydrocarbon generation and late accumulation during the early Himalayan period. Studies of the Huangqiao, Jurong and Taishan areas show that the current oil and gas pools mainly formed during the late accumulation period. Marine basin occurrence and their geologic structure, effective hydrocarbon source and preservation conditions are key factors for the late accumulation of hydrocarbon.