Fine Structure Interpretation And Exploration Target Optimization Of The Second To Triassic In The Fengnan 5 Well Block Of The Junggar Basin

FN5 region is located in the Urho fault-fold belt within the middle and western area of the Urho uplift on northwestern margin of the Junggar basin,East near Mahu Depression,connect with the Ke-Bai fault-fold belt in the northest.The studied target formation were Permian and Triassic,the overall structural features performance of the upper and lower two slip surface in the vertical,and performance of“two concave and a convex”in the plane.The formation of lower Permian show as SW thick NE thin,and the upper Permian formation thickness had flipped performance of NE thick SW thin.The Permian denudation occurred before Triassic deposition,formed the regional unconformity contact between Permian and Triassic.The target layer lithology of lower Permian is clastic rock,argillaceous dolomite,volcanic rocks,upper Permian and Triassic mainly is clastic rock.the clastic reservoir mainly is low porosity and low permeability of work area,Individual layers could reach medium porosity and medium permeability,overall physical property is poor.In this paper,as for the work of fine structural interpretation with 3D seismic data of work area as basis,Structural geology and Sedimentary petrology,Seismic stratigraphy as the guide,from the accurate calibration of horizon and the stratigraphic framework establishment,secondly,apply the application of fault identification technique to find out the formation strata contact relations,and seismic reflection characteristics and fracture characteristics of Permian and Triassic,completed different levels of fault interpretation and plane combination.As for Structure research,primarily well-to-seismic integration established the early duplex of the thrust structure,advanced shear structure;Then,through the post stack seismic data processing and interpretation of body curvature and other technical means to further improve the small fault identification and characterization of precision,Based on velocity analysis and fine structural interpretation through the variable velocity mapping complete the structure plan map of the layer such as T₂k2,P1j,P₁f,P₂x,P₂w,T₁b,T₂k.last,it is considered that the Permian and Triassic in the study area are characterized by two concave and convex structures,the main part of the developmentis is the north west axial nose uplift belt,along the nose belts in rows with the reverse fault.Study on reservoir characteristics,research by single well sedimentary and well sequence stratigraphic correlation,combined with previous research,It is clear that the Permian and Triassic are lacustrine facies and fan delta facies,The favorable reservoir is mainly distributed in the fan delta front underwater distributary channel and sheet sand;Seismic reflection characteristics of different sedimentary facies and subfacies are established by well-to-seismic horizon calibration,and the use of sensitive seismic attributes analysis and prediction of key strata in the sedimentary facies distribution of the macro,successfully predicted facies and development characteristics of the scale of the Permian and Triassie layers of fan delta front favorable group.Study on structural characteristics and sedimentary characteristics provide reliable guarantee for reservoir prediction and target optimization.On the basis of the analysis,this paper studies the characteristics of reservoir lithology,structure and physical properties,and the seismic attribute analysis and inversion technology to identify the favorable traps and trap characteristics.To assist in the discovery and implementation of 8 structural traps,1 fault stratigraphic traps,5 lithologic traps.Reservoir-forming rule and reservoir shows that the development of various types in work area,Permian Fengcheng formation developed fault-block oil reservoir,the Permian and Triassic reservoir in each layer of group types are mainly lithologic reservoirs against fan delta deposits and tectonic setting,fault has a segmentation effect on reservoir.According to the comprehensive evaluation and optimization of favorable targets,assist the work area to identify 7 exploration targets.In addition,to describe and evaluate the P₂x₂ and dolomitic sandstone reservoir of the FN5 region.