The Main Controlling Factors And Favorable Area Of The Lacustrine Shale Gas Enrichment In The Shahezi Formation Of The Changling Depression,Songliao Basin

In the Changling area of the Songliao Basin,the muddy shale is rich in organic matter and muddy shale,and the Lower Cretaceous Shahezi Formation shale is the main source rock layer in this area.In order to find out the geologic conditions and enrichment of the main factors in the continental shale gas of the faulted basin,screen the favorable area of the continental shale gas in Shahezi Formation of Changling fault depression,in this paper,the shale of Shahezi Formation is selected as the research object,and the geologic interpretation,balance profile,basin simulation,geochemical test and logging interpretation are used,based on geological,seismic,geochemical and logging test data,the typical shale samples were analyzed to clarify the characteristics of shale geology;The structural characteristics of Changling fault depression are analyzed from two aspects of plane and profile,and the evolution process of fault depression is analyzed with the history of burial and equilibrium;The correlation between gas content and various factors was analyzed to determine the main controlling factors of shale gas enrichment;Finally,it is preferable to determine the preferred parameter for the favorable area.The main conclusions of this paper are as follows:?1?The total abundance of organic matter in the Shahezi Formation of the Changling fault depression is 0.45%¹1.96%.The kerogen type is dominated by II₂ type,and the total thickness of shale shale in Shahezi Formation is 500¹200m;?2?The regional uplift of the Huoshiling Formation occurred mainly in the Heidi Temple.The uplift of the Yingcheng Formation affected most of the sub-depression in the study area and was less affected in the southwest of the study area.The regional uplift of the sedimentary facies occurred in the southeastern part of the study area,and the rest of the sediments occurred only at the deposition rate;?3?The accumulation of organic carbon,maturity,quartz content,clay mineral content,fault displacement and distance from the fault are obtained by the accumulation of soil shale gas in Shahezi Formation of Changling fault depression.;?4?In accordance with the optimization of the favorable area,the shale gas favorable area of the Shahezi Formation is mainly distributed in the sedimentary center and the surrounding area,these areas of shale thickness,organic carbon content is high,is conducive to shale gas enrichment.