Fault Characteristics And Evolution Of Middle-Lower Jurassic In Eastern Taibei Sag,Turpan-Hami Basin

The study area is located in the eastern side of Taibei sag in Turpan-Hami basin.With the deepening of exploration,it has become an important block for oil and gas exploration in Taibei sag.The faults in the study area are very developed and play an important role in controlling oil and gas accumulation.However,the research on the characteristics and evolution of faults in this area is still relatively weak.On the one hand,the quantitative characterization of the growth and connection process of thrust faults and strike-slip faults is still very weak,and a systematic characterization scheme has not been formed.On the other hand,the formation and evolution process of thrust faults and strike-slip faults in the study area is not clear,and there is a lack of systematic research on the distribution characteristics,development stages and growth connection process of faults.In addition,the fracture geometry,kinematics and dynamics characteristics of the study area need to be solved urgently.In order to grasp the fracture characteristics and evolution of the middle and lower Jurassic in the eastern part of Taibei sag,this thesis mainly studies the fracture characteristics and evolution of the middle and lower Jurassic in the eastern part of Taibei sag based on the seismic interpretation data of the eastern part of Taibei sag and other data such as logging,mud logging and field geological outcrop.The occurrence and distribution characteristics,fracture distribution law and fracture formation period of different faults in the outcrop area are clarified,and the geometry,kinematics characteristics and dynamic mechanism of thrust and strike-slip faults are summarized.On this basis,the relationship between fault ring,fault cap and fault source is clarified,and the control effect of faults on hydrocarbon accumulation is summarized.The results show that :(1)The fault in the outcrop area nucleates in the competent rock stratum,and is constrained by the non-competent rock stratum.In the early stage,it mainly expands horizontally.With the stress support,it finally breaks through the non-competent rock stratum and grows vertically.Affected by the strain difference,the outcrop area develops embedded structures controlled by different levels of strike-slip faults and thrust faults;(2)The fault deformation of the Middle-Lower Jurassic in the eastern part of the Taibei Sag is dominated by thrust faults and supplemented by strike-slip faults.It has the characteristics of zonal,segmented and layered fault deformation.The primary and secondary faults are characterized by segmented growth,with nucleation at the bottom and upward expansion.The characteristics of development,bounded by the detachment layer,have the characteristics of strong fault deformation at the upper and weak fault deformation at the lower.The faults were mainly formed in the middle Yanshan period,developed and finalized in the Himalayan period;(3)The oil-source faults in the middle and lower Jurassic in the eastern part of Taibei sag are very developed,which provide sufficient transport channels for oil and gas generated by source rocks to enter traps and accumulate,and control the plane and vertical distribution of oil and gas.The key factor determining the vertical migration of oil and gas is the coupling relationship with the caprock,which affects the vertical migration distance and distribution horizon of oil and gas.The effectiveness of fault ring configuration depends on the lateral sealing of faults.The effective fault ring configuration controls the lateral accumulation of oil and gas,and the ineffective fault ring configuration controls the lateral adjustment of oil and gas.