Hydrocarbon Expulsion History of Mesozoic Source Rocks and Resource Potential in Kuqa Depression

For revealing the potential force of gas and oil exploration in Kuqa Depression,the hydrocarbon expulsion history and the characteristics of hydrocarbon expulsion of the studied area were analyzed by using the method of hydrocarbon-generation potential.The results show that,firstly,the peak of oil expulsion of the Triassic source rocks is started at 23 Ma,it is earlier than Jurassic source rocks(12Ma).At this time the ancient trap was destroyed,and new trap is formed later than 23Ma.It is not beneficial for Triassic source rock accumulation.Secondly,the exhaust volume of the Triassic and Jurassic source rocks is larger,and the exhaust time is coupled better with that of new trap formation,which is favorable for late gas accumulation.Thirdly,the gas of the Triassic source rocks is difficult to break through the giant thick mudstone in middle and upper Jurassic,but the condition is advantageous to the natural gas accumulation in the Jurassic traps.Fourthly,Kuqa Depression developes deep basin gas source conditions and tight reservoir conditions,which is favorable for the formation of large area of deep basin gas reservoirs,and the slope of Baicheng Sag and Yangxia Sag is the potential of deep basin gas resource area.