| Shunbei area of Tarim Basin has become one of the key areas for oil and gas exploration and development.The lower Paleozoic strike-slip faults in the study area control the development of fault-karst reservoirs.However,due to the large difference in hydrocarbon enrichment between different sections and positions of these strike-slip faults,and the small vertical fault displacement at very deep burial depth,the characterization of internal architectures has become a hot spot and a difficult point.In this study,the Shunbei No.1 strike-slip fault zone(SB1 fault)and the Shunbei No.5strike-slip fault zone(SB5 fault)were taken as the research objects,which are in Shunbei 1 working area,Shunbei 8 working area and Shunbei 8 north working area.Based on the 3D seismic data,well logging data,core data and microscopic observation data of the three working areas,the internal configuration of strike-slip faults and the research results of fault-karst reservoirs were fully utilized.The geometric characteristics of strike-slip faults were firstly started,and then combined with the fault activity characteristics,the internal configuration characteristics of strike-slip faults were fully realized.Secondly,the types of fault-karst reservoirs space are defined,and the internal structure of fault-karst is quantitatively classified.Finally,the fault-karst reservoirs controlled by internal architectures is proposed based on the distribution law.Given the strike-slip fault has tiny difference in phase axis slip in the seismic sections,we take the perspective of the plane first,and beginning with structure oriented filtering of data volume,improve the signal-to-noise ratio and resolution,and then 10typical strata of lower Palaeozoic era to track,and extract sections of coherence and curvature,combined with the 3D seismic profile interpretation,The longitudinal stratification and transverse segmental differential deformation characteristics of the strike-slip fault zone in Shunbei area are defined.The structural style of the main faults in the early Caledonian are relatively simple,and it is mainly linear and parallel in strip.The main changes in the profile are main in the T81 interface,showing negative flower shape,Y shape and reverse Y shape.The main characteristics of the middle Caledonian episode?,mainly developed in the T74 interface.In addition to the linear and parallel plane shapes,there are also pull-apart joints,compressional joints,left and right steps,horse-tailed faults and braided faults.The profile is characterized by flower and composite flower structures,graben and horst.From late Caledonian to early Hercynian,the plane characteristics of Shunbei area are mainly characterized by anechelon structure,in which SB1 is left and right step,and SB.5 fault is left and right step.In the early Hercynian period,the Shunbei No.1 fault north segment maintained the right echelon,while the Shunbei No.5 fault changed from south to north.With the help of curvature attribute bedding slices,the concept of using attribute slices of different scales to observe and describe the characteristics of fault plane configuration is introduced in fault research,and the stratigraphic relief caused by fault tectonic activity is reflected on the plane in the way of color change.(1)The plane segmentalization of strike-slip faults can be analyzed,which is mainly reflected in that the forward structure of the uplift superimposed section is linear in the center,and the direction is along the fault strike,and the boundary faults are around in a ring or parallel shape,while the tensile section is on the contrary,and the main characteristic of the shift section is linear parallel arrangement of the ascending disk and the descending disk.(2)From the bending changes of the steps,the extrusion and extension properties of the steps can be judged from the plane,and according to the direction of the steps,it can be inferred that the SB5 fault along the north of the T74 interface is right-lateral movement,while the SB1 fault along the north of the T74 interface is left-lateral movement.(3)According to the curvature for large scale fault sensitive attributes,we can find that along the SB5 northern section of fracture pressure lung spliced with obvious late pull-apart movement trace,and cause the formation of pressure rise curve traces can be found in annular T70 interface,determine suitable pressure spliced zone is roughly five fractures formed during the middle Caledonian episode?.(4)Under the scanning of large-scale curvature,the echelon normal faults at the T70 interface of the SB5 fault in the north part of Shunbei Basin are obviously different by the turning point of fault strike.The graben in the north part is in the form of compression,while the graben in the south part is nearly connected,indicating that the compression activity in the north part stops later than that in the south part.Based on the structural horizon and tectonic movement periods,the vertical fault displacement of shallow structure and deep strike-slip fault in SB1 fault zone were calculated.Statistical fault zone along the SB5 middle Caledonian?episode vertical"uplift"slip,and advanced vertical slip"fall".Statistical results show that vertical slip along the north has at least four stages of tectonic activity early Caledonian,middle Caledonian,late Caledonian and early Hercynian,and lead to SB strike-slip fault points and structure characteristics of the deep and shallow.Along the SB5 T74 interface fracture section peace pad pressure ridge activity time and the start of the middle Caledonian episode?and stop before episode?,and the SB5 fault mainly deceloped around the Caledonian?episode.According to the statistical result that the vertical fault displacement between the T63 and T60 interfaces of the overburden strata is obviously larger in the south than in the north,it shows that the south segment of the SB5 fault begins to reverse before the north segment due to strike reasons as the direction of maximum principal stress rotates from NE to NNW,and the leading structural connection mode changes from right-to-left order to left-to-right order.The tectonic inversion in the late Caledonian formed a large number of flower structures at the interface of T74,while the interface of T70 inherited the form of early stratigraphic uplift and formed the flower structure.The overlying graben develops from top to bottom with T70 as the strongest active interface,and most of them are connected with the underlying strike-slip faults unilaterally and widen the main section.Along the SB1fault belt pull-apart basin main activities during the middle Caledonian episode?,nowadays the deep tectonics roughly formed in middle Caledonian?episode.In addition,the difference of tectonic deformation trend reflected by vertical fault displacement indicates that the shallow anechism activity can be divided into late Caledonian and early Hercynian with the boundary of T63.Shallow goose row activities are dominated by T70,and the active interface develops from bottom to top,and there is little connection with the underlying strike-slip section.There is a positive correlation between the vertical"uplift"fault displacement of T74 interface and the fault zone width of T74 interface:y=0.0726x2+15.85x+196.95,R~2=0.7749;The fault displacement(absolute value)at the T74 interface of Shunbei No.1 fault was positively correlated with the fault width at the T74 interface:y=42.206x+137.74,R~2=0.7404.The main reservoir space types of fault-karst in Shunbei area are fractures and dissolved pores and caves.Based on a room set of natural gamma logging data,calculation of characterization of fluid due to faulting after legacy of abnormally high shale content parameter?Vshi,accordingly think when measuring point?Vshi;At 2.5%,the surrounding rock is considered to be in the fault zone;The characteristic value of fault fracture zone is 2.5%<?Vshi?6.5%;When?Vshi=6.5%,it is the boundary value of fracture zone,namely?Vshi more than 6.5%are characteristic of the fault zone core.The results are in good agreement with the actual production and the predicted reservoir distribution.The plane and profile distribution characteristics of the fault-karst are fully analyzed.The fault-karst in the original profile is characterized by abnormal strong reflection,disorderly reflection,and dislocation of the in-phase axis.On the amplitude difference profile,the fault-karst developed along the fault in columnar or elongated form,or parallel arrangement on both sides of the fault.In the plane,the fault-karst is circular or linear and parallel,and also distributed along the fault or on both sides of the fault.In addition,compared with the results of vertical fault spacing and prediction of reservoir boundary,it is considered that high point in the superimposed zone of large compressive uplift has a better response.The boundary of faul-karst is constrained by the width of fault zone either in plane or in section.The internal architectures of the strike-slip fault zone and the superposition of plutonic karstification are the main controlling factors of the fault-karst reservoir. |
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