PETROLEUM SYSTEM ANALYSIS OF THE NORTHERN SAG, THE SOUTHERN YELLOW SEA BASIN

There is a graben-like sag with fault in the north and overlap in the south caused by severe block faulting effect from Mesozoic to Palaeogene in the north of the Northern Depression of the Southern Yellow Sea Basin.Lacustrine facies dark mudstone deposited during Taizhou and Funing periods is the main hydrocarbon source rock in the sag.CyClic movements such as Yizheng and Wupu movements result in superposition of reservoir and source rock,forming multiple sets of source,reservoir and cap formation.Traps as antiCline,fault nose and fault block are generated.Oil and gas in Taizhou Formation migrates through weathered zone in fault and unconformity and sandstone carrier bed to the up,the south and the slope,forming types of accumulations as lithologic,antiCline and fault nose.The sag is an independent petroleum system.Petroleum bearing traps distribute like a string of beads along the Qianliyan Fault Belt and the Slope Pivot Belt,which are the most favorable regions for exploration in the Southern Yellow Sea Basin.