The Research Of The Base Structure Characteristics In The North Of Songliao Basin

Drilling results show that the bedrock weathering crust,bedrock fissures of Songjiang Basin contain a lot of natural gas,because it can be determined that there have natural gas accumulation in the dense sandstone and volcanic rocks,we should further expand the exploration of new areas.With the deepening of exploration work and the discovery of a large number of new phenomena,the basement of northern Songliao Basin shows a certain exploration potential,so this study selected this area as the study area.However,due to the low degree of interpretation of the basement seismic data in the study area,and the existence of structural interpretation of the multi-solution;exploration wells revealed little results on the bottom of the substrate,so far the base of the probe can only see the basal surface lithology,But most of the basal surface rocks have a large degree of metamorphism,lack of in-depth and accurate understanding;previous studies are mainly for a single basin of various aspects of system analysis,but for the entire Songliao Basin structural characteristics and evolution process of analysis Shallow.Therefore,this paper makes a structural interpretation of the two large-scale seismic large sections in the study area,and calibrates the regional unconformity surface,explains the regional tectonic pattern,establishes the structural framework of the study area,and analyzes the profile evolution characteristics,the dynamics of the basal development of the study area and its mechanism;to lay the foundation for exploring the new oil and gas accumulation in the field of exploration.The main findings of this study are as follows:Based on the interpretation of seismic profiles,this paper interprets the structural distribution of the study area by using some exploratory basins and the latest regional geological data.The study area mainly forms the four kinds of tectonic styles of extension,extrusion,inversion and transformation.The tectonic patterns of the Upper Paleozoic strata in the study area are mainly puff-like thrust,tectonic wedge,broken folds,slip-off structures,high-angle thrust faults and so on.Based on the background of the tectonic events in the study area,the structural profile of the study area is analyzed by using the results of seismic section interpretation.Through the study,it is considered that the main structure of the study area is three layers,The bottom structure layer is a number of thrust fault or slip structure,and thrust in the process of reverse thrust often formed fracture fold,broken folds.The central tructure layer is for a wide range of sliding surface.The top structure layer is an inverted-thrust nappe that moves in the northwest direction.In addition to E line,the whole fault is gradually uplifted to the north.From the plane map,The fault of the study area has the characteristics that n the east-west direction is divided into bands,in the north-south direction class is divided into blocks.Nearly north-south fracture activity and the relative torsional slip between the broken fault blocks causes the characteristics that n the east-west direction is divided into bands.NNE and NE direction of the fault zone is controlled by the near-north-south direction of the large fracture.It is obvious that the fracture has a structural feature with a left-handed push button as a whole.The tectonic model of the Upper Paleozoic strata in the study area can be divided into two types.(1)The internal tectonic geological model of the paleo-uplift zone is a multi-stage inverted-tectonic nappe structure.(2)The early cretaceous faulted zone for typical crowded before they pull the vicious flat structure.The post-Paleozoic strata developed from the Upper Paleozoic strata in the study area make the Late Paleozoic strata developed on one or the bottom of the steep slopes of the Cretaceous rift basins,which are relatively thin,and the upper Paleozoic strata thickness relatively thick.