The Study On The Characteristics Of Chang8Reservoir In Dongzhi Region,Xifeng Oil Field

With the development of domestic oil exploration and production, both the reserves and outcome of low and extremely low permeability reservoirs increase year by year. The efficient development of this kind of reservoir is very important to the stable development of oil industry in China, and thus it has important social and strategic importance. The low and extremely low permeability reservoir has poor reservoir physical property and inadequate natural energy, which leads to the low final oil recovery. Water flooding is the key technology to improve the development level and achieve sustainable development of this kind of oilfield. However, understanding reservoir geology is the security of improving the effect of water flooding.This paper takes the main oil region in Xifeng oilfield as a case study to investigate the capacity characteristic and water flooding countermeasure of the fractured extremely low permeability reservoir. In this paper, the study of sedimentary microfacies, flowing units classification as well as core analysis experiments were conducted, and thus the reservoir rock microstructure, physical characteristics and flow characteristics were understood. The focus of the study is to realize the capacity characteristic and the affecting factor and rule of the capacity. On this basis, water flooding development plan and technical strategy of stabilizing oil production and controlling water cut were proposed.The main conclusions can be summarized as follows:1. By using of cycle correlation and hierarchical control method, Chang81layer can be divided into Chang811, Chang812-1, Chang812-2and Chang813. Sand body development of Chang811and Chang813are limited, which are discrete reservoir sediment formed in the late and early stages of the sediment in the case of lack of source supply. The sand body development of Chang812-1and Chang812-2are extensive. They are formed in the case of sufficient source supply. After the deposition of Chang812-2, it was transformed by Chang812-1layer and formed stack sand body, belonging to clustering reservoir sediment.2. The studies of sedimentary facies indicate that Chang81layer is delta front facies. The microfacies of the studied area can be divided into such three types:subaqueous distributary channel microfacies, river mouth bar microfacies, subaqueous interdistributary embayments. Chang8i2-1and Chang812-2layers are the main reservoir belonging to subaqueous distributary channel microfacies. Chang811and Chang813layers belong to river mouth bar microfacies and subaqueous interdistributary embayments. They both have relatively poor reservoir capacity.3. District81major reservoirs in the Central Research-fine sandstone and fine sandstone composition, pore type intergranular pore, feldspar dissolution holes, debris dissolved pore. Reservoir having an inner layer of strong interlayer and flat heterogeneity.4. Effective use of different micro-facies sand thickness, the average porosity, permeability, flow zone index, using fuzzy math cluster analysis, reservoir evaluation classification discriminant analysis, the study of81reservoirs were fine mayor of flow cell division, and divided into four kinds of flow unit types. Studied the distribution of the small plane layer flow cell.5. Research mayor81reservoir characteristics, the type of flow unit production wells, injection wells and the water absorption capacity of the movement of the reservoir has a significant role in controlling.