Petroleum exploration potential in abyssal zone of Qiongdongnan Basin, South China Sea

The evolution of the Qiongdongnan Basin in the South China Sea can be divided into three stages including intracontinental rift during Eocene, rift during Oligocene, and passive continental margin depression ever since Miocene. Multiple sets of petroleum generating materials of different facies were deposited in abyssal zone. For example, lacustrine facies in the first stage, marine-continental and continental facies in the second stage, and marine facies in the third stage. Three high thermal fluid events took place during the three evolution stages, contributing to the maturation of source rocks. Multiple types of reservoir and multiple sets of reservoir-cap assemblage provided abundant room for the enrichment of petroleum. Various types of trap formed during stages of tectonic movements were favorable for accumulation.