HYDROCARBON SOURCE ROCK EVOLUTION IN TAIZHOU FORMATION, THE GAOYOU SAG, THE NORTH JIANGSU BASIN

Researches on burial,temperature,maturity and oil generation histories of hydrocarbon source rocks of Taizhou Formation in the Gaoyou Sag,the North Jiangsu Basin with basin modeling methods have indicated that,hydrocarbon source rocks of Tai2 Member have entered mature stage and R_o has reached 0.6% during the early Sanduo period.As stratigraphic burial depth increases,stratum temperature,source rock maturity and hydrocarbon generation ability also increase gradually.In the end of Sanduo period,stratigraphic burial depth,temperature and hydrocarbon source rock maturity have reached the maximum,3 000 m,110℃,0.8%,respectively.At the same time,oil generation also reaches the maximum,and oil generation content of Well Jiao1 in the east reaches 350 mg/g.So,Sanduo period is the main stage during which Tai2 Member source rock generates and discharges hydrocarbon.In addition,tectonic and fault activities are strong during Sanduo period and most traps are formed.Therefore,Sanduo period is also the favorable and main period for oil-and-gas migration and accumulation.