Fine Structure Interpretation And 3D Geological Modeling Of XN Area In Northern Songliao Basin

XN area is located in the middle of Daqing placanticline in the north of Songliao Basin.At present,XN area is in the late stage of high water cut development.Finding remaining oil and adjusting injection-production relationship have become one of the key issues for the sustainable development of oilfield.The enrichment of remaining oil and the adjustment of injection-production relationship are closely related to the neglected micro-amplitude structures and small faults in the early stage of exploration and development.In this paper,fine structural interpretation is carried out for XN oilfield,micro-faults are identified,micro-amplitude structural characteristics are clarified,and structural modeling is carried out on this basis,which provides important support for fine reservoir description and remaining oil distribution research.Based on the theories of structural geology,stratigraphy and geophysics,this paper makes a three-dimensional visual interpretation of the SII,SIII and PI structures in XN area.Aiming at the problems of unstable reflection phase,poor continuity,large variation of amplitude intensity and large interpretation workload caused by multiple interpretation horizons in the study area,Fastgrid intelligent interpretation software was used to complete the interpretation of four structural horizons with an interpretation accuracy of 11 by using ’partition calibration and three-dimensional visualization intelligent interpretation technology based on phase conversion ’.Using fault enhancement and other filtering techniques,using seismic attributes such as coherence body,dip angle attribute,curvature body and ant body,combined with well breakpoints,the faults,especially small-scale faults,are identified,interpreted and combined from plane,section and three-dimensional space,and finally the full three-dimensional interpretation of 27 faults is completed.The time-depth relationship is created by well-seismic calibration,and the seismic horizon is used as the structural trend constraint to calculate the spatial velocity field.The structural maps of four layers in the study area were obtained by using variable velocity mapping technology,and the structural error was less than 0.18 %.Identify 12 micro-amplitude structures.Based on the seismic interpretation of XN area,combined with the geological stratification data and well breakpoint data in the study area,the structural modeling is carried out by using Petrel software.Under the constraint of fault polygon,based on the spatial interpretation of strata and faults,the spatial location and intersection relationship of faults and strata in the whole area are clarified,and the matching of well breakpoints and faults,geological stratification and tectonic horizon are ensured.Finally,a structural model with sedimentary unit level and accuracy of 20 m × 20 m × 0.2m is established.The results obtained in this paper provide the direction for further tapping the potential of XN area and finding the remaining oil,and provide the basis for the formulation of the follow-up development plan of XN area.