Fault Characteristics And Its Controlling Effect On Oil Of Shahejie Formation In 3^rd Area Of Nanpu Sag

With further development,the local structural zones and Low level faults have become the key research object to increase potential production for oilfield.3^rd Area lies in the southeast of Nanpu Sag,influenced by complex tectonic evolution,it has a large number of faults,which play an important role in controlling the formation and distribution of hydrocarbon.Nowadays,where the main exploration layers have reached deep Shahejie formation,unclear fault characteristics and short of research have seriously affect the understanding of deep oil and gas reservoirs,also restricted the development of target area.Based on pre-understanding,combined with fine interpretations about 3D-seismic,this paper comprehensively utilizes geological,logging,production data etc to study systematically the fault characteristics of Shahejie formation.Summarize fault geometry;analyze quantitatively regional acting evolution;apply numerical simulation to visualize ancient and modern stress;do profound analysis about fault controlling effect on reservoirs finally,which will be helpful to the following exploration of oil and gas reservoirs and deepen the overall understanding of Nanpu Sag.Mainly achieved the following conclusions:?1?Using fine structure interpretation and comparison to find out that faults are divided into three types in large,medium and small size,strike in NE^EW,the fault density increases gradually from deep to shallow;faults are parallel or oblique in plane,showing structural styles such as"anti y","conjugate x"in the west section,ladder-type mostly in the east section.?2?Through formation thickness,Fault acting evolution during sedimentary period of Shahejie formation is studied by methods of growth index and paleo fall with sectional evaluation,showing that this research area had experienced two extensional deformation stages in NW–SE and S–N with Es₁ as boundary,while the direction of regional stress rotate clockwise,extension intensity was presented alternately as strong to weak;The balanced cross-sections verify this feature,also show it has experienced periodic extension in"strong–weak–strong–weak–strong".?3?Based on acting evolution analysis,taking multiple stratas and faults into considera-tion,ancient and modern tectonic stress fields are reconstructed by numerical simulation,then analyze in detail the characteristics of modern tectonic stress of Shahejie formation,do fault propagation analysis through stress mechanisms,make fault properties and development periods clear,point out that anticlockwise rotating stress caused regional extension.?4?Through connecting-well section types and distribution of deep oil and gas reservoirs are found out,combining fault activity with ancient and modern stress,the oil and gas pool-forming models are built according to the controlling sand bodies and induced fracture of faults,modern tectonic stress,results show that the favorable migration-accumulation trend of hydrocarbon is from sides to center,oil and gas migrated from source rocks to the shallow through faults and sand,eventually was capped to form reservoir by Ed_2,and the southwest is a favorable area for hydrocarbon.