Characteristics of Tectonic Evolution in the Qiongdongnan Basin and Brief Discussion about Its Controlling on Reservoirs

Qiongdongnan basin is a Cenozoic petroliferous basin.In this paper,according to analysis of main controlling factors on regional tectonic evolution in the Qiongdongnan basin(i.e.spreading of the South China Sea,Red River Rift,the Pacific plate,etc.),in combination with features of the internal sequences and faults in the Qiongdongnan basin,the tectonic evolution of Qiongdongnan basin in Cenozoic Era can be divided into three stages: Tectonic evolution of multiphase rifting stage from late Cretaceous to late Oligocene,thermal subsidence stage from early to mid-Miocene Epoch,and new tectonic stage in late Miocene Epoch.Based on the tectonic evolution of Qiongdongnan basin,we discuss the correlated function of tectonic evolution to formation of source rocks,reservoirs,cap rocks and traps,an then point out that the structurally adjusted middle area in the Qiongdongnan basin(i.e.Yabei sag,Songxi sag,Lingshui low uplift,Songtao salient,Lingshui sag,Songnan sag,central low uplift,Beijiao sag) would be the profitability of oil and gas accumulation,which is possible to achieve a breakthrough for the future exploration of oil and gas in the Qiongdongnan basin.