伏龙泉断陷沙河子组—登娄库组天然气地球化学特征与成藏过程OACSTPCD

Taking the Shahezi Formation and Denglouku Formation gas reservoirs in the Fulongquan Fault Depression as an example,based on the experimental analysis of source rocks,natural gas geo-chemistry,reservoir fluid inclusions and isotopes of carbonate cement,it carried out studies on gas source correlation,accumulation history and reservoir formation process.The results show that the gas in the Denglouku Formation is coal-derived and the source rock is primarily the local Shahezi Formation.The accumulation of oil and gas in the Shahezi Formation began at the end of Quantou Formation and continued to be charged until the end of Nenjiang Formation.The natural gas accumulation in Den-glouku Formation is mainly in late Mingshui Formation.Shahezi Formation is conducive to the forma-tion of primary gas reservoir.Natural gas of Denglouku Formation is reformed from deep and high ma-turity natural gas.The key to controlling the gas accumulation in Denglouku Formation is the positive paleostructure or primary paleotrap developed in the source rock layers,the effective allocation of the"through-source"fault and the cap layer of Quantou Formation.Both sides of the uplift belt in the mid-dle of the fault depression are close to the hydrocarbon generating center,and the"through-source"fault develops,which is conducive to the formation of gas reservoirs in Denglouku Formation.The extruding stress at the end of the fault in the hydrocarbon generating depression area is strong,and the tight gas in the source is well preserved,which is the favorable direction for the next exploration.