Thick Oil Reservoir High Water Cut Of Pattern Adjustment To Increase Water Flooding Recovery And Technological Measures

The residual oil has the characteristics of thin layers, scattered distribution, small areas, poor physical properties and low driving energy at high water-cut stage due to serious heterogeneity in Shuanghe oilfield. The traditional well pattern adjustment technologies such as infill drilling and subdivision of series of strata are not suitable in the circumstances.Based on the goal of comprehensive well pattern adjustment at super-high water-cut stage, through the systemic studies of geology and reservoir engineering in the paper, some important outcomes and conclusions were elicited.The highlights are as follows. The 3-D fine geologic models were established by subdivision of flow units vertically and sub-facies laterally and seeking for sub-structures by using the architectural elements of reservoir. An evaluation system of residual potential tapping in thick oil layers was established and the distributions of residual oil at high water-cut stage in Shuanghe oilfield were characterized and predicted accurately, prediction accuracy up to 80%, by using new reservoir engineering methods and 3-D two-phase fine numerical simulation technologies in this paper.The notable outcomes are that the relevant technical limits of comprehensive well pattern adjustment at super-high water-cut stage were also determined, and that a series of comprehensive well pattern adjustment technologies at super-high water-cut stage were developed to meet the requirements of injection-production structure adjustment and enhance water-flooding recovery factor. The pilots in the development unit IV1-3 in the northern block of Shuanghe oilfield were successful both technically and economically with water-flooding recovery factor increasing from 46.28% to 49.5%. it proves that the regrouping of flood pattern modification according to flow unit not only develops and enriches the technology of traditionalpattern adjustment but also makes an new way to improve developing effect and water-flooding recovery at high water-cut stage of oil field.Besides, the detailed studies on microcosmic distribution of residual oil in pore network were also accomplish by various new methods or technologies, such as water flooding experiment of imitating model and NMR imaging. These researches deepen further the understanding about the microcosmic distribution of residual oil in heterogeneous porous media at high water-cut stage.