The Study On Structural Features And Deformed Mechanism In The Northern Wuerxun Sag In Hailer Basin

Hailar Basin is a meso-cenozoic of multicycle, composite-style, fault-sag basin. It is the focus of the Daqing oil field in the peripheral basin exploration by its special tectonic location, strong post-stage rebuilding, Multi-stage reservoir forming and the accumulation of oil and gas. Wuerxun sag is where Hailar Basin especially explores.The study will be based on previous research, comprehensive analysis and collation of the existing geology, drilling and seismic data, make full use of extensional tectonics, compressional tectonics, inversion tectonics and fault-related fold structures, such as new theories and new methods, this text carry on systematic deep research to the structural feature and evolution law of Wuerxun sag, decompose Multi-phase composite basin, and study on structural characteristics of the sag each time; understand the structure formation mechanism, get the structural geology understanding with the actual regional tectonic deformation features, Strategy for the next phase of oil and gas exploration and lay a solid foundation. Through the thesis research, the main access to the following understanding:(1) Discussed the situation of regional geological background and strata of the northern Wuerxun sag in Hailer Basin(2) Through geology, drilling and seismic data analysis and combining with the previous situation of seismic interpretation, the main seismic reflection interface in the northern Wuerxun sag was identified and determined.(3) Make the synthetic seismogram of exploratory wells and evaluation wells in the work area, and marked horizon, through cross-comparative analysis of the drilling and seismic sequence, so that make the drilling and seismic sequence boundary demarcation unified; realize the seismic reflection layer unified in northern Wuerxun and establish regional structure stratigraphic framework by building connecting-well section and main seismic sections. Completed the structural interpretation of T04-T5 seven major seismic reflection layer.(4) Set up section structure pattern of Wuerxun sag and analyze the genetic mechanism; according to the developmental characteristics of different periods in the fault system of Wuerxun sag, identify the combined regulation on vertical and horizontal based on seismic section; determine the fracture types and distribution in different periods; analyze the different fault system of the lower structural layer and the central structural layer.(5) Make the division of structural layer based on regional geological data, geophysical data, structural style, etc., that is, the upper structural layer, the central structural layer and the lower structural layer; and structure of each layer were carried out in detail.(6) Through the analysis of structural feature, structural layer and structural style of the northern Wuerxun sag in Hailer Basin, we produced a profile of evolution history of the northern Wuerxun sag, and described that Wuerxun sag experienced two stages of fault acti vity and one stage of depression activity. In addition, the detailed analysis of the first time of fault activity are carried out, make the profile of evolution history. According to the analysis of the structural layer and the profile of evolution history, we believe that the Wuerxun sag is superimposed by three periods of basin, namely the early fault basin, the middle fault basin and the late sag basin.