| Oilfield water flooding development generally contains four stages, including initial water cut stage, middle water cut stage, high water cut stage and extra-high water cut stage. At present, the majority of the oilfields in our country have entered into mid-high and high water cut stage. Long-term water erosion leads to increasing reservior heterogeneity, which easily causes water breakthrough in area of high-porosity and high-pemeability and generate dominant seepage channels, finally different levels of the dominant area converge into dominant flow field. The generation of dominant channels will cause the re-enrichment of remaining oil and lots of invalid water cycle among oil and water wells. There is an important guiding significance to understand the distribution of dominant channels, and its level for the adjustment of injection-production meseasures, furtherment tapping of remaining oil, and the improvement of oil displacement efficency.Though the existing research ideas and methods at home and abroad, the seepage behavior of reservoir can be analyzed, and the advantage channel can be distinguished, there still exist three deficiencies:1. Static or dynamic analysis only without organic combination;2. Relevance of production wells and injection wells has not been clearly proposed in the dynamic analysis;3.Clear classification standards of dominant channel have not been made.H3IV53layer of eight-zone in JingLou oilfield is the main oil development layer, and now has reached the stage of mid-high water cut after20years of waterflooding development. It exists difference of this layer between north and south, and water can not be injected into layer in north. The flood effectiveness in south block is good, but producing wells works unevenly, the overall development of H3IV53layer is not ideal.Using of existing methods and techniques, through the reservoir sand distribution, heterogeneity and connectivity of high porosity and permeability reservoir analysis, this paper has qualitatively analyzed the reservoir layer H3IV53dominant seepage area; then make qualitative discrimination between injection and production wells dominant seepage channels according to historical data of the production blocks, the amount of fluid produced by mining oil changes, changes in injection water injection wells, injection wells correlation curves, according to historical data of the production blocks, the amount of fluid produced by mining oil changes, changes in injection water injection wells, injection wells correlation curves, mathematical correlation between injection and production wells, tracers to determine the correlation methods. Finally combine dominant reservoir seepage area with injection wells and dominant seepage channels, derived H3IV53final layer flow channel.This study is different from previous analysis of a single reservoir or injection correlation analysis. This paper makes comprehensive analysis on the various influence factors on the dominant channels formation, and takes use of the most reliable data analysis and correlation analysis, and make comparation with the reservoir physical properties dominant seepage area, finally propose dominant seepage channels. In such cases that water can not be injected in the well groups of high permeability reservior or water injection intensity is high in the well groups of low permeability reservior, causes have been analyzed and reasonable injection countermeasures have been proposed. On the basis of the dominant seepage channels, according to the porosity and permeability properties, the annual amount of injection and produciton, water cut, water injection intensity, and other parameters to formulate the classification standards of dominant channel grade, classify the grade of dominant seepage channel. According to the classification results, guide on-site water injection adjustment, to achieve the best water injection effects and improve oil recovery. |
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