Research On Development Effect Of Water-Flooding Well Pattern Optimization And Adjustment Of Typical Blocks In Xingbei Pure Oil Areas

Through 40 years of water-flooding development process in Xingbei development area, well pattern ranging from basic to third infilled pattern gradually changes from row-column to five points method area well spacing and injection-production well spacing reduces from 600 m to 141 m. Development object transfers from the best kind of reservoir and thick oil layers having effective thickness of no less than 2.0m to thin and poor reservoir, which has entered into the development period with ultra-high water cut and remaining oil distribution is highly fragmented. Under the condition of current well pattern, there exists development contradictions such as non- balance in vertical reservoir usage, controlled by minor layers in plane, lower producing degree, restricting further improving water-flooding development effect. In order to fully tap the potential of remaining oil, redivision of layers and rematching of injection-production well spacing are essential to be based on characteristics of reservoir development, searching an effective way to improve water-flooding development effect in high water cut stage.This paper is based on the detailed understanding of stratigraphic structure and reservoir characteristics of the west of Xing4 block, 3D geological model is built by Petrel geological modeling software, and historical match has been proceeded according to dynamic data of field, liquid production or water cut fitting accuracy within 3%. Calculation of minor layers and recovery degree is respectively 2352.69×104t and 43.39%. By analyzing vertical and plane remaining oil distribution at present and water cut of 98%, adaptability of well pattern and adjustment of encryption are researched, adjustment plans of layer system are formulated and optimized from development effect and economic benefits. Results show that plan 3 is the optimal well spacing plan, namely saertu good layers of 200 m row-column well pattern, saertu poor layers of 141 m five points method well pattern, PⅠ4 and below layers of 141 m five points method well pattern, in which three layer series are used so that water cut decreases by 3.08%, recovery efficiency increases by 4.70%, and net income reaches highest. The conclusion will provide reference for improving the producing degree of minor layers in high water cut stage.