Electrical Characteristics Of Basement Structures Of Three Basin Groups In Northeast China

In recent decades,geological research in the Northeast region has always been carried out around the basin.From the most beginners only focusing on the oil and gas resources in the basin,to the formation and evolution of the basin,and then to the base of the basin.Structural characteristics.More and more studies have shown that the identification of basin basement characteristics and fault systems is of great help in exploring the formation and evolution of basins.Through the study of basin basement structure,the mechanism of basin evolution and basement fractures are clarified.The characteristics also help us to better understand the control effect of the basement on the basin's tectonic evolution and stratigraphic deposition,as well as to identify the boundary of the basin,and then guide the exploration of resources such as coal mine oil and gas.As one of the important petroleum and coal mining bases in China,Northeast China has also nurtured many Mesozoic-Cenozoic sedimentary basins.Among them,the Songliao Basin,Sanjiang Basin,Hulin Basin and Hailar Basin have attracted more and more people.The more people conduct research on this area,its special geotectonic location and rich prospects for oil and gas resources make this area a basis for the development of basic geological and petroleum geological theories,and realize breakthroughs in new areas,new areas and new strata systems for onshore oil and gas exploration in China.One of the important areas.With the development and application of deep reflection seismic profile method,broadband seismic reflection and magnetotelluric sounding method,the deep geophysical exploration work in Northeast China has made great progress and provided richness for subsequent research.Valuable information,but due to various factors such as the working period or the different instruments used to collect data,the explanations obtained in the same area are not exactly the same.Therefore,this article collects and sorts out the geological research work of the predecessors in the Northeast region,summarizes the current research status of the major basins in the Northeast region in China,summarizes the instruments and inversion methods used by the predecessors in various regions,etc.The research is divided into three regions,focusing on Songliao Basin,Dasanjiang Basin Group and Daxinganling Regional Basin Group.In the study area,more than 40 geophysical sections in the Northeast were collected and screened,and the sections with longer survey lines and more intersecting sections were found,including 6 electrical sections in the Songliao Basin and Dasanjiang Basin group 7 electric method section,5 electric method sections in the northwest Daxinganling basin group,the section fabrics are analyzed,and three grid-like diagrams are obtained.At the same time,the predecessor's knowledge of the area is absorbed,and the study area is further completed.The interpretation of the characteristics of the basement of the basin,and the following conclusions are drawn:(1)The Songliao Basin shows a trend of high-low-high in terms of electrical properties,with a large-scale low-resistance area in the middle,from the Sunwu-Shuangliao fault zone to the east The low-resistance area on the side is reduced,showing a low-resistance-high-resistance and low-resistance-high-resistance-low-resistance structure,while the west side does not start to become high-resistance until the Nenjiang fault,and the change is more rapid than that in the east.The faults in the south have more complex structures.The electrical resistance in the south is far greater than that in the north.The thickness of the sedimentary caprock of the entire basin is obviously controlled by the faults.(2)The high resistance range of the Dasanjiang Basin Group gradually decreases from the Jiamusi block to the north to the south to the east.The resistance value of the Jiamusi block has small fluctuations and the lithospheric structure is stable.The resistance value of the Xingkai block has little change and is relatively stable.Compared with the Wandashan block,the upper and lower resistance values ??are different,and the lithospheric structure is unstable.However,among the several plots,the more to the northeast,the larger the low resistance range,which further confirms the unity of the "big three rivers" basin to a certain extent.(3)The east-west direction of the Daxinganling area has the characteristics of horizontal division and vertical stratification,which can be divided into three structural units: Hailar Basin,Daxinganling and Songliao Basin.The eastern margin of the Hailar Basin and the shallow part of the western margin of the Songliao Basin are characterized by low resistance,and the Daxinganling as a whole is characterized by high resistance.The eastern margin of the Hailar Basin and the western margin of the Great Hinggan Mountains have similar electrical structures of the lower crust and upper mantle,which may belong to the Xing'an block.The north-south shallow layer in the northwest has a high and low resistance distribution.Compared with the more complex base features in the south,the Ergun-Xing'an microplate in the north has a more stable lithospheric structure.