准噶尔盆地沙湾—盆1井西凹陷深层油源断层类型及有效性:以征沙村地区为例OA

The oil source fault is the key point of reservoir accumulation.There are difficulties for the identification of oil source faults in the deep layers of Shawan and western well Pen-1 sag,because of low-quality seismic data,strong multiplicity of faults and sparse wells which reach the source rock layers.This study takes the example of the Zhengshacun area which has findings in the upside source rock layers,using techniques of seismic interpretations,oil and gas migration simulation and correlation analysis to confirm the fault development features,oil and source fault types and their effectiveness.Conclusions of this study are:1)Permian layers develop NNW and EW thrust faults,the activity was strong in Fengcheng and Xiazijie Period and was weak at the stage from Lower Wuerhe Period to Upper Wuerhe Period,some faults changed into strike-slip faults and were active after Triassic Period,Triassic layers mainly develop EW-trending and small scale,and nearly SN-trending strike-slip faults in parallel arrangement,the activity was weak at the Baikouquan Period and strong from Kelamayi to Badaowan Period.2)There are three typical oil source fault types,including inherited type,relay type and strike-slip faults type.The inherited type developed thrust faults from Fengcheng Formation to the Lower Wuerhe Formation and changed into the strike-slip fault from Upper Wuerhe Formation to Badaowan Formation.The distribution morphology is similar between the deep(Permian layers)and shallow layers(Triassic layers).The fault in the south and north of the Zheng 10 well is the typical example.The strike-slip fault type is the strike-slip fault developed from Fengcheng Formation to Badaowan Formation,and the distribution features are similar between the deep and shallow layers;but the deep layer fault is less clear than the shallow layers in both plane and sections.The fault in the south of the Zheng 2 well is the typical example.The relay type consists of thrust faults from Fengcheng to Lower Wuerhe Formation and strike-slip faults that started at the end of the Permian and these two types connect at Upper Wuerhe Formation and Baikouquan Formation.This type is the intersection point between deep and shallow faults in the plane.The fault in the north of Zheng 6 is the typical example.The study area mainly develops the inherited type and fault-sand type fault,the pattern consists of the strike-slip fault and the first period sand-bodies of the J1b,which is most beneficial for oil and gas accumulation.3)All three types are effective oil and source faults,but the inherited type and relay type are more beneficial for oil and gas accumulations.The above understanding can provide more evidence for the identification of oil-source faults and conductivity analysis.