Characteristics Of Upper Permian Source Rocks And Prediction Of Favorable Areas In The Northern Area Of Songliao Basin

The research area in this paper is the northern Songliao Basin and the eastern and western marginal areas of the northern basin,mainly including Moguqi gas in the northeast of Inner Mongolia,Suolun,Linxi,Dashizhai,northern Songliao Basin and Heilongjiang in the eastern margin of the Songliao Basin Province Acheng,Yichun and other regions.Based on 6 measured profiles and 31 drilling data in the basin,the lithology,sand body distribution characteristics,source rock types,distribution characteristics and geochemical characteristics of the Upper Permian strata in the study area were studied.On this basis,make full use of previous research results to explore the Late Permian lithofacies palaeogeographic features,Upper Permian source rock characteristics and hydrocarbon generation potential in the study area,and carry out research on the Upper Permian in the study area The source rock is beneficial to the prediction work of the remote area.The study of Upper Permian stratigraphic characteristics in the study area mainly starts from the characteristics of lithology and stratigraphic development.The study found that the Upper Permian strata in the western part of the study area are controlled by the Hegenshan-Heihe fault zone,which is mainly distributed in the east of the fault zone;the western margin of the northern Songliao Basin is mainly developed by large sets of mudstone,mud slate,and mud shale.Linxi Formation represented by etc.;Sizhan slate formation represented by mud slate and Lindian altered volcanic rock represented by altered andesite,altered siltstone,and mud slate are mainly developed in the northernIV Songliao Basin The Hongshan Formation is mainly developed in the eastern margin of the northern Songliao Basin,and the lithology is dominated by mudstone,silty mudstone,and silty fine sandstone;the Permian strata developed in the study area as a whole are thick in the west and thin in the east,and in the north of the basin The stratigraphic thickness of the four-station slate formation is generally larger than that of the Lindian Incident Volcanic Formation(thickness of drilling encounter).The characteristics of lithofacies and paleogeography in the study area were studied by combining the field survey profile with the drilling lithology,sedimentary structure,and development characteristics of sand and mudstone.The results show that the main part of the Late Permian strata in the study area is a continental environment,and the marine environment is locally developed in the southeast of the study area;the sand body distribution characteristics reveal that there are three provenances in the study area,namely the Jiamusi ancient land in the northeast and the frontier in the northwest.The ancient source area of Erguna ancient land and southwest Linxi area,of which the northeast and northwest are the main source directions;the late Permian in the study area mainly developed mudstone facies,sandstone facies,mudstone-sandstone facies,sandstone-mudstone facies Lithofacies and fan deltas,lakes,deltas,and shallow sea shelf are four types of sedimentary facies;sandstone corresponds to fan delta facies,mudstone-sandstone corresponds to delta front facies,and sandstone-mudstone corresponds to shallow sea shelf and deep lake.The semi-deep lake facies and mudstone correspond to the development of deep lake-semi-deep lake facies.The analysis and statistics of the Upper Permian source rocks in the study area show that: the source rocks of the Upper Permian in the study area are mainly mudstone,mud slate,slate,and silty mudstone;the Upper Permian in the study area The distribution characteristics of source rocks are similar to those of the Upper Permian mudstones.The mud-land ratio is low in the surroundings and high in the middle.From the periphery of the basin to the center of the basin,the mud-to-land ratio gradually increases.The Zhaodi area represented by Well 1 has a main mud ratio of up to 73.6%.Geochemical data analysis of the Upper Permian source rocks in the study area shows that the medium-good source rock samples in the study area account for more than 72%,indicating high organic matter abundance;77 samples in the study area show that the source rock organic matter types in the whole area are Type ? is the main type,and type ? kerogen is developed in some sections and wells.The test data of individual drilling samples shows type ? kerogen;the highest pyrolysis temperature,vitrinite reflectance,and diagenetic stage indicators indicate the Upper Permian hydrocarbon source The maturity of rock organic matter is in the stage of high maturity-overmaturity;organic geochemical characteristics show that the Upper Permian source rocks in the study area have the potential for hydrocarbon generation,but the degree of thermal evolution is relatively high,mainly gas generation.Combined with the Upper Permian lithofacies palaeogeographical features and source rock features in the study area,the predecessors have analyzed and analyzed the structural thermal evolution and burial history of the area: the Sauron area in the northern margin of the northern Songliao basin and the Zhaoyuan in the northern Songliao basin The area is a favorable remote area for the Upper Permian source rocks in the study area.