History of hydrocarbon accumulations spanning important tectonic phases and its hydrocarbon differential accumulation of Sinian Dengying Formation in Sichuan Basin

Sichuan Basin has undergone three stages of important tectonic events at the end of Early Paleozoic, Late Paleozoic-Early Mesozoic, and Late Cenozoic. These tectonic events have put strong influence on hydrocarbon generation, migration, accumulations of Sinian Dengying Formation. Hydrocarbon differential accumulation of differential areas has been controlled by multi-stages tectonic activities. By studying the history of tectonic movements, the distribution of ancient oil and gas accumulation and present gas reservoir, history of hydrocarbon accumulations spanning important tectonic phases has been recovered. Gaoshiti-Moxi gas-bearing structure is an inherited uplift, where natural gas has been mostly efficient accumulated. But Dingshan area of Southern Sichuan Basin was different, traps were damaged during the late gas accumulation stage, while ancient trap existed during the period of oil generation in for there was so much bitumen. The crucial period of hydrocarbon was from Later Jurassic to Early Cretaceous, the Qiongzhusi Formation of lower Cambrian reached a high generation, liquid hydrocarbons after thermal cracking became gaseous hydrocarbon in palaeo-reservoir, which gaseous hydrocarbon formed present reservoir after accumulation.