The Study On Reservoir 3D Modeling Technology Based On Pre-stack EI Seismic Inversion

This paper takes an oversea H oilfield as examples,study on reservoir 3D modeling process and investigate how pre-stack seismic EI inversion could improve the quality of reservoir model.Firstly guided by Sedimentology and Sequence stratigraphy theory,H oilfield F stratum structure evolution stage is clarified using seismic,outcrop and well logging curves data.Secondly establish Sequence stratum framework,conclude sedimentary facies type and distribution characteristics.Thirdly apply sedimentary facies3 D model using geo-statistics approach.Finally accomplish F reservoir 3D porosity model constrained by facies model and seismic pre-stack EI inversion.Delicate 3D seismic interpretation is performed to pick typical Top,Mid and Bottom seismic reflect horizon of reservoir stratum.Structure framework is built by these three horizons.The main reservoir of H oilfield deposit in Jurassic rift period,east azimuth normal fault and west azimuth normal fault form a typical horst-block style structure reservoir.Assess how structure factors contribute to reservoir modeling.Analogy analysis is carried upon outcrop sedimentary structure and the vertical evolution of facies with other similar marine clastic rocks,set up the facies types and classifying basis for F interval.Comprehensive apply outcrop observation,logging curve and well logging data to establish high resolution sequence framework.Combine singlewell facies types,lithologic thickness map and seismic waveform attribute map to accomplish sedimentary facies system distributional map under the constraints of sequence framework.Assess how sequence framework and sedimentary facies factors contribute to reservoir modeling.Build 3D high resolution velocity modeling for research area.To deal with the problem of velocity significant change between both side of large scale normal fault,this paper come up an velocity modeling method by integrated using seismic internal velocity volume,well time-depth curves,well surface pick,seismic horizon and fault interpretation data,finish building the final hybrid velocity model with structure framework support,seismic data constraint and well velocity interpolation.Data timedepth conversion is done by through 3D velocity model.Discuss how velocity modeling is important to reservoir modeling.Based on the theory of elastic impedance(EI)seismic inversion,collected pre-stack seismic dataset including 0~10,10~20 and 20~30 degree stacking volume.Perform EIseismic inversion for F interval and analysis the difference between EI seismic inversion and traditional P wave impedance seismic inversion.Assess how EI seismic inversion is contribute to reservoir modeling.On the basis of seismic interpretation,structure framework construction,sedimentary facies identification and EI seismic inversion,a 3D facies geological model is simulated by Plurigaussian Stochastic simulation approach for F interval.Then porosity 3D model is also simulated by Sequential Gaussian Simulation under the constraints of facies model.Investigate the source of 3D geological modeling uncertainty,and access uncertainty between model and well sample data by “Direct Comparison”,“Probability Distribution” and “Leave-Out Analysis” method.