塞152区块注水压力快速上升机理研究与防治

Research and Treatment on High Waterflood Pressure on Block Sai 152

安塞油田塞152区块2000年投入注水开发,原始地层压力6.12MPa。随着油田开发时间的延长、累计注水量的增加,注水压力快速上升,由初期5.6MPa上升到目前清水系统的14.5MPa,污水系统压力上升到18.5MPa,导致系统压力超过设计压力,地层吸水变差,水驱效率降低,严重影响开发效果。采用敏感性分析的方法,对水质伤害、注入水与地层水的配伍性进行分析研究,确定了塞152区块注水压力快速上升的形成机理,通过室内试验和筛选,进行注低浓度表面活性剂降压增注试验,收到较好的效果。

Block Sai 152 in Ansai Oilfield started waterflooding extraction in 2000. its initial formation pressure was 6. 12 MPa. With continuous development and increase of accumulated injection rate, waterflooding pressure rockets from initial 5.6MPa to 14. 5MPa of present fresh water system and 18. 5MPa of polluted water system, which causes higher system pressure than design pressure, weakness of layer water sucking and low waterflood efficiency, thus affecting development results. This paper determines the formation mechanism of rapid rising of injection pressure of Block Sai 152 through sensitivity analysis, water damage analysis, and analysis of waterflood compatibility with straturn water. It also makes experiments on depressurization and augmentedinjection by injecting surfactant with low concentralion which presents remarkable effects.