Heterogeneity Of Low Permeability Reservoir In Block 5 Of Bonan Oilfield

The 5th block in Bonan oilfield is a deep low permeability reservoir and has entered the high water stage. Affect by the reservoir heterogeneity and other geological factors, the producing reserves in vertical is quite different, the main oil reservoir is water flooding, the law of the remaining oil distribution is unclear. Carrying the heterogeneity study can reveal how does the remaining oil distribution control the oil and water migration, and predict remaining oil enriched area, and provide geological evidence to oil field development plan.Firstly, this article carrys out stratigraphic subdivision and correlation and establish fine stratigraphic framework for the characterization of low permeability reservoir heterogeneity; On this basis, to fine sedimentary microfacies and diagenesis study reveals the impact of heterogeneity factors, we suggest that the sedimentary environment and diagenesis affect the low permeability reservoir heterogeneity of the controlling factor; Striking heterogeneity through quantitative parameters, interbeds research and analysis of tracer experiments, microscope, thin sections, such as mercury data analysis, comprehensive study of the reservoir layer, the layer, flat and micro-heterogeneous characteristics, summarized in the study area in low permeability reservoir 4 heterogeneous model, three kinds of distribution of pore structure and its main facies types, comprehensive characterization of the reservoir heterogeneity; calculate the heterogeneous synthetic index of the reservoir ,characterize the heterogeneity of the reservior comprehensively and reveals the characteristics of remaining oil distribution from the point of reservoir heterogeneity;Based on the well logging interpretation, the oil reservoir profiles and plane distribution of fluid are analyzed, the heterogeneity of the reservoir is further revealed. Applying with the study result, combining production performance date, the paper indicate the control action of the heterogeneity, from internal lamination, interlamination, plane and micro size, to the distribution of residual oil, and get the corresponding characteristics. The study shows that the main sedimentary facies zone, the imperfect flood pattern area and the joint position of different sedimentary facies are rich in residual oil in lateral while the main layers with certain thickness, wide area and good porosity and permeability in the vertical. The research results of this this article have an important guiding significance on enhancing recovery of in Block 5 of Bonan Oilfield.