The Research On The Structural Physical Simulation Of Left-lateral Strike-slip In Red River Fault Zone,Yinggehai Basin

The Yinggehai Basin experienced a left-lateral strike-slip movement along the Red river fault zone during the Oligocene-Miocene(32 Ma~5.5 Ma),with a strike-slip distance of approximately 200-400 km.During this period,the Yinggehai Basin experienced a rapid advance strike-slip.At the late stage,the process of tectonic inversion gradually ceased and some northwest-southeast geese-like faults were formed,and an inversion structure was developed at the Lingao uplift and the Henei depression.The formation of the fracture system has become the main channel for the early oil and gas migration and accumulation in the basin,and directly controls the basic pattern of the basin's current structure.Because there are few researches on the fault system formed by the left-lateral strike-slip of the Red river fault zone in the Yinggehai Basin,the shallow 3D seismic data has a fuzzy zone in the diapir zone,while the deep crusts in the deep basin have a huge thickness,which leads to the formation of left-lateral strike-slip.The fracture system cannot be accurately identified,and the migration path of oil and gas migration in the basin is unclear,which has seriously affected the research progress of basin tectonic evolution and sedimentary accumulation.Taking the left-lateral strike-slip effect of the Red river fault zone in the Yinggehai Basin as an example,this paper sets up two physical models of shear structures based on the characteristics of basin evolution and similarity: classic Riedel shear left-turn strike-slip model and diffuse shear left-turn strike-slip model.Setting the experimental stratum conditions of mean quartz sand,glass bead-quartz sand,and glass bead-quartz sand-silica gel according to the lithologic characteristics of the formation.The experiments were performed by photographing,PIV,and section slicing.The process and results were recorded.Finally,the results of the simulation experiments were compared and verified with the interpretation results of 2D and 3D seismic data.The fault system formed by the left-lateral strike-slip of the Red river fault zone in the Yinggehai Basin is being played up.The experimental study found that under different formation experimental conditions,the mean quartz sand model formed a small number of strike-slip faults,and its striking structure was obvious.It intersected along the strike-slip direction at the large angles of the basement faults,and developed farther along the sides;glass beads and quartz sands.The model has formed more strike-slip faults with more striking structures,intersecting strike-slip directions with small angles of the basement faults,and developing along the two sides.The glass bead-quartz sand-silica gel model forms a large number of strike-slip faults.The structure is not obvious,and intersects with the micro-angle of the basement fault along the strike-slip direction,and is basically close to the basement fault.At the same time,the study found that the classic Riedel shear-rotational strike-slip model has concentrated strain bands.The formed strike-slip fracture system is mainly distributed along the sides of the strike-slip base fault,with R-type faults as the main faults and erected at high angles.It intersects with the basement fault and forms a typical flower-like structure.The fault formed on the inner side of the left-lateral strike-slip has a smaller inclination angle and a larger distance between the basement faults;the diffuse shear model,which forms a strike-slip The fracture system is mainly distributed along the R-type strike-slip fault on both sides of the basement fault.The strike-slip faults formed on the inside penetrate each other through the entire model,forming a large fault-faulted strike-slip fault formed by left-lateral strike-slip.It extends into the dispersive zone and does not intersect with the basement faults.They constitute a typical flower-like structure.The strike-slip faults formed on the inner sides of the strike-slip base have smaller dip angles and have a larger distance from the basement fault.The fault system formed by the left-lateral strike-slip of the red river fault zone in the Songhai Basin is the result of the joint action of the shear model and the stratigraphic model.The shear model controls the characteristics of the shape distribution of the strike slip fault,The stratigraphic model controls the characteristics of the number of strike slip faults.These characteristics have different effects on basin forming.