Sedimentary Microfacies And Reservoir Heterogeneity Research In Bohai BZ Oilfield

Based on the data of drilling, core, logging, seismic, reservoir, dynamic production performance and laboratory analysis, this study comprehensively applied three ways of traditional deposition cycles contrast, 3-D seismic phase-oriented constraint detection and deposition model trend tracking to carry out substratum division and sandbody correlation, reservoir microfacies and heterogeneity studies, establishment of main reservoir deposition model, implementation of the sedimentary facies distribution, reservoir plane, interlayer and inner-layer heterogeneity, which provided an important basis for water injection program, water injection effects analysis, structural adjustment of producing liquids, integrated oilfield adjustment, deployment of adjustment wells, and studies of enhanced oil recovery.(1) Based on the comprehensive utilization of core, logging and seismic data, a set of methods on substratum division and single sandbody correlation was explored, which can be applied to other similar fields for reference.(2) Based on the further study of laboratory core analysis data from the standard well in this zone, the single well phase analysis of this zone was conducted, by which to establish logging model of the area, summarize logging micro-phase interpretation mode and to recognize the deposition mode of BZ oilfield as shallow water delta.(3) The sedimentary system mode of BZ oilfield was confirmed based on the deposition background and core analysis. Generally speaking, the sedimentary mode of BZ oilfield is shallow water delta. Combined with 3-D seismic data, maps of sandstone thickness, sandstone percentage and the logging series were compiled, which showed the sedimentary microfacies distribution of each substratum and evolution of sandbodies.(4) The studies of inner-layer, interlayer and plane heterogeneity of the reservoirs in Lower Member of Minghuazhen Formation were conducted, and it elaborated porosity and permeability characteristics of each sedimentary facies unit and gave a macro-evaluation to the reservoir heterogeneity of this zone.(5) The reservoir connectivity model of this oilfield and the injection validity characteristics of reservoirs in various connectivity mode were summarized by the verification of production dynamic performance data, which provided an important basis for oil production in the future.(6) Geological study methods and means for the development of Bohai BZ oilfield were systematically summarized, which provided reference for similar oilfields in Bohai Bay. And some of these methods have already been applied in some fields.