Characteristics and development model of subtle faults in Bashijiqike Formation,Dabei area,Kuqa Depression
As a Tarim Basin Cenozoic regenerated foreland basin,the Kuqa Depression is characterized by the development of imbricate structural wedges under salt.With the continuous development of gas reservoirs,many gas reservoirs have water invasion in different degrees.Previous studies have shown that the subtle fault,as a high permeability channel to communicate bottom water or edge water,is the main cause of water invasion,the effective identification of subtle faults directly affects the development effect of gas reservoirs.However,due to the influence of gypsum-salt strata,the seismic resolution of subsalt structures is low,and it is difficult to identify the subtle faults by using seismic attribute method.Taking the Dabei X structure as an example,this paper adopts the idea of combining geology with geophysics,and based on the 3 subtle faults identified by drilling and seismic attribute methods,based on the fault distance-distance curve and stress analysis,two types of subtle fault development models are established.The results show that the formation of the subtle fault is controlled by both local stress field and regional stress field.The main thrust fault structural transition zone is the dominant developing position of the subtle fault.With the fault growing and connecting in segments,the structural transition zone will gradually change from the state of extrusion stress to that of strike slip stress,the strike of the subtle fault will also change.The strike-slip component of the regional stress is another important factor to control the strike of the NE-trending subtle fault when it is far away from the main boundary fault.The results of this study will provide important geological constraints for the identification and prediction of subtle faults in the greater North Bozi area of the Kuqa Depression.
Kuqa DepressionThrust faultSubtle faultFault throw-distance curveDevelopment model
万方数据
维普
