Hydrocarbon Exploration Prospect Analysis Of Lower Cretaceous In Sankeyushu Fault Depression,Tonghua Basin

In recent years,the oil and gas geological survey of the Mesozoic residual basin in the southeastern part of Jilin province shows a good prospect for exploration,but limited to the complex structure and volcanic activity of the mountain area,the oil and gas exploration in this area is restricted.Tonghua Basin is located at the Tieling-Jingyu anticlise zone in the eastern part of the northern margin of the North China Plate.It is located in the mountainous area in the southeastern part of Jilin Province.It is a polygonal faulted basin with an area of about 485km~2.With the further study of the Tonghua basin,the base of the Tonghua basin is the metamorphic complex of the Archean,the ancient rocks of Proterozoic and the Paleozoic,and the Mesozoic Jurassic,Cretaceous and local Quaternary system are mainly developed in the basin.The Jurassic mainly developed Hou Jia Tun formation,and the Cretaceous system mainly developed fruit pine group,hawk mouth group,Lin Zi head group,lower birch peelian group,Hengtong mountain group,three elm tree group and hehewei subgroup.The whole formation of three stage volcanic rocks to volcanic clastic rocks and four stage fault basin sedimentary basin filling construction.Through the balanced section technique and restoring the structural evolution section of the Tonghua basin,it is known that the Cenozoic era of the Tonghua basin mainly experienced seven stages of evolution,which occurred in six stages of filling,suffered four tectonic movements and formed the interaction of three sets of Lake Basin deposits and volcanic filling.Through single well phase analysis and seismic data interpretation,there are 3sedimentary facies,7 subfacies and 11 kinds of microfacies in the Mesozoic of Tonghua,and 11 kinds of microfacies and 7 subfacies.The fan delta depositional system,the sedimentary period of the Hengtong formation,has formed a lake basin sublacustrine fan delta depositional system with relatively small sedimentary area.According to the core test analysis of the study area,the source rocks in Tonghua area are developed,and the hydrocarbon source rocks of the lower birchbedidizi formation are high in organic matter.The type of kerogen type is dominated by type I and II type 2 kerogen,which is in the mature evolution stage.It belongs to middle to good source rocks and is the main source rock in the region.There is an important source of supply.According to the results of the drilling test in the study area and combining with the data of well logging and earthquake,it is concluded that the"Xinli~Xinjia Street"area in the northern part of the three elm fault depression of the Tonghua basin is a favorable target for the oil and gas exploration in Tonghua area,and its volcanic piercing structure is the accumulation of oil and gas.The place of interest.