Fine Resevroir Deseription Of The Chang-2 Reservoir Of Yanchang Formation In FuChang Area Of Ordos Basin

Based on the new theories of modern fine reservoir description, by using theories and techniques of the high-resolution sequence stratigraphy, astronomical period, sediments, quantitative geoscience, reservoir geology, modeling of geology, carried out the research of the fine reservoir description of Chang 2 reservoir of Yanchang formation in Fuchang area of ordos basin.1. According to the corresponding relation between geological cycle and astronomical period, under the restrict of deposition time Ott period and eccentricity long period Q. using high-resolution sequence stratigraphy theories and well logging of physical geography data, Yanchang formation of Triassic is divided into long term cycle and medium to long term cycle in the studying area, and isochronous stratigraphic framework is established. In this way, division of substrata bases on the time surface as interface which is a time-stratigraphic unit. It can avoid considering the different deposition time stratums as the same ones.2. On the basis of the sedimentary background, the sedimentary microfacies in the oil pool are studied. Base on the subfacies, the microfacies is further studied. Beach sand dam, natural levee, floodplain in Chang 21, Beach sand dam, natural levee, marginal bank floodplain in Chang 22 are discussed. Meantime, the sedimentary microfacies pattern is given by dominant facies'thick strata of sand over the previous value of the thickness of strata, and the plane distributive maps of sedimentary microfacies for Chang 21 and Chang 22 substratum are drawn.3. From the petrology, microscopic structures and features of reservoir, diagenesis, analysis of well logging interpreting, flow units division, heterogeneity of the reservoir, the basic characteristics of the target zone are integrately studied.4. Flow units division:using the clustering analysis method, by FZI division, the reservoir is classified to five flow units kinds ofâ… ,â…¡,â…¢,â…£,â…¤,and relatively established corresponding relation between porosity and Permeability. The same kind flow units have similar or identical microscopic pore structure and Rock physical property.5. heterogeneity of the reservoir:using the concept of quantitative geoscience of Fuzzy Mathematics, combined several kinds of parameter-Permeability, the average thickness of sandbodies, stratification coefficient, sand matrix density, interlayer frequency and interlayer density, comprehensive index I of heterogeneity of the target zone is calculated. The reservoir is classified using the method of the comprehensive index I of heterogeneity.6.3D geological model is developed with petrel software. By combined approach of the sequential Gaussian-Bayesian simulation with the Object Modeling, model of sedimentary facies is developed. Using "sediments controlling" theory, model of property is finished. All these provide the geological foundation for future numerical simulation and development of the residual oil.