Research On Hydrocarbon Generation Conditions Of Mesoproterozoic Xiamaling Formation In Xiahuayuan Area,Xuanlong Depression

This paper takes the Xiamaling Formation in the Xiahuayuan area of the Xuanlong Depression as the research object,conducts a large number of literature surveys,field investigation,sample collection,organic geochemical analyzation and basin simulation,etc.;Comparing the characteristics of organic geochemical and element content in the surrounding area,it is concluded that hydrocarbon generation conditions are systematically analyzed and summarized.Proterozoic source rocks in my country are mainly concentrated in the three major cratons.Among them,the North China Craton is typically represented by the Hongshuizhuang Formation Shale and the Xiamaling Formation Shale with the most exploration potential.Compared with the Hongshuizhuang Formation,the Xiamaling Formation,the most important exploration layer of the Proterozoic in North China,is thicker,more widely distributed,and contains higher organic content.The Xiamaling Formation is widely developed in the Yanshan area,in which the Xuanlong Depression is the center of deposition and subsidence during the Xiamaling Formation.The Xiahuayuan area has the most complete and thickest Xiamaling Formation.The climate is warm and humid,the surface water is rich in oxygen,and the reducing environment at the bottom is anoxic,providing a good depositional environment for the Xiamaling Formation.In this area,the black shale in the third member of the Xiamaling Formation is the most developed,with an average total organic carbon content(TOC)of 4.23% and a maximum of 6.42%.It is a good source rock type;the organic maturity(Ro)is 0.55%,and the maximum pyrolysis peak temperature(Tmax)is 441?,thus,the degree of thermal evolution is relatively low.the organic matter type is dominated by type II,and the source rocks of the Xiamaling Formation are in the oil generation stage.Comparing existing organic geochemical parameters with surrounding areas such as Jianchang in western Liaoning,Kuancheng in northern Hebei,Jixian in middle Hebei,and Xishan in Beijing,it is found that the Xiamaling Formation in Xiahuayuan area has the highest abundance of organic,the thickest source rock formation,and the best hydrocarbon generation conditions.The Xiamaling Formation has good source rocks.Lower organic maturity indicates that volcanic activity has not effectively promoted hydrocarbon generation.The transition area from the subtidal zone to the edge of the lagoon is the best place for the development of source rocks in the Xiamaling Formation.Analyzing by Basinmod,the historical burial depth of the Xiamaling Formation in this area can reach more than 3400 meters,with mature evolution conditions,and it is a prospective area for oil and gas exploration.Generally speaking,the Xiamaling Formation is a set of good source rocks with high abundance of organic matter and low thermal evolution.The Xiamaling Formation in the Xiahuayuan area is the area with the most complete development,the thickest source rock,and the best source rock quality in North China,and it has good prospects for exploration.