Geological Research Of Low Permeability Sandstone Reservoir In Block Zhuang 62-66 Of Wuhaozhuang Oilfield

Block Zhuang 62-66 of Wuhaozhuang Oilfield is the middle-deep low permeability reservoir. The main oil-bearing layers include Es2,upper Es3 and â…  oil group of lower ES3. Divided stratigraphic boundaries are not uniform in the study area, understanding of distribution regular pattern for sedimentary microfacies is unclear, accuracy of research is not enough,and fundamental studies of reservoir heterogeneity and stress and crack distribution rules have not been conducted.Aiming at these problems, by comprehensively utilizing seismic, logging and production dynamic data, fine stratigraphic division and comparison to target layer are conducted and stratigraphic boundaries are unified,and the division and correlation grid of layers are re-established to reveal the formation distribution disciplinarian. On this basis of stratigraphic and sedimentological study,three kinds of sedimentary facies and Eleven kinds of sedimentary microfacies are identified from top to bottom in this study area. The more developed microfacies includes braided channel microfacies,underwater distributary channel microfacies and beach-bar microfacies. Further the distribution characteristics of various sedimentary facies are discussed and sedimentary facies models of turbidite fan, fan delta and beach-bar is established.Through quantitatively striking reservoir heterogeneity parameters and intercalations research, Inner-layer inter-layer and lateral Heterogeneity of reservoir are studied to sum up five heterogeneity models of low permeability reservoir and its main distribution phase in sedimentary facies and comprehensively represent heterogeneity characteristics of reservoir in the study area. On the basis of preliminary geological understanding,the research of distribution disciplinarian to stress and reservoir fracture is expanded. By understanding the regional tectonic background and striking rock mechanics parameters,paleo-present stress field and crack distribution of target layers are comprehensively analysed in the study area,and the distribution of high-quality reservoir is predicted.Studies suggest that due to the influence of fault,deposition and other factors,the varietions are larger in the sedimentary sections of different layers at different locations in the study area,overall showing the feature that the thickness is thinner in the south than north and in the west than east.Sedimentary microfacies control reservoir sand bodies distribution and connectivity and physical changes,which is an important factor influencing reservoir heterogeneity.Sedimentary facies and reservoir heterogeneity controls the degree of enrichment of the remaining oil.Ancient tectonic stress field controls the formation and development of cracks,the current stress field has an important influence on the validity of cracks. Braided channel microfacies, underwater distributary channel microfacies and bar microfacies are reservoirs of high-quality.The research results provide geological basis to adjust oilfield development plan and has important guiding significance to improve oil recovery.