低渗油田高压注水井在线酸化技术研究与试验

Research and Test on Online Acidification Technology of High Pressure Injection Well in Low Permeability Oilfield

为实现对注水井的酸化解堵及增注降压的效果,保障低渗油田开发的高效性与安全性,对低渗油田高压注水井在线酸化技术进行研究和试验分析。制备复合酸液体系,确定在线酸化施工中的注酸速度与强度等参数,并设计在线监测装置实时监控在线酸化施工,检验结果表明,该复合酸液具有较高的螯合性与沉淀抑制性,具有较高的岩粉溶蚀率;应用该复合酸液实施在线酸化施工,施工后试验注水井的地层吸液性及注水量显著上升,井口油压及施工压力显著下降,增注降压效果明显,可解除注水井储层的堵塞物,为提升低渗油田开发的安全性与高效性提供保障。实验结果表明,所提技术使井口的油压由9.11MPa降到1.71MPa、泵注压力由9.77MPa降到7.51MPa,说明能有效缓解井口油压以及泵注压力,加大整体的施工排量,实现增注降压的目标。

In order to realize the effect of acidizing plugging removal and increasing injection pressure reduction of water injection wells,and en-sure the high efficiency and safety of low permeability oilfield development,the online acidification technology of high pressure water injection wells in low permeability oilfield is studied and tested.The composite acid system is prepared,the parameters such as acid injection speed and intensity are determined,and the online monitoring device is designed to monitor the online acidification in real time.The test results show that the composite acid has a high chelation and precipitation inhibition,and has a high dissolution rate of rock powder;After the application of the composite acid liquid in the online acidification,the formation liquid absorption and water injection volume of the test water injection well increases significantly,the wellhead oil pressure and construction pressure decrease obviously,and the effect of increasing injection and reducing pressure is obvious,which can remove the blockage of the water injection well reservoir and provide guarantee for improving the safety and efficiency of low permeability oilfield develop-ment.The experimental results show that the oil pressure of the wellhead decreases from 9.11 to 1.71MPa and the pump pressure decreases from 9.77to 7.51MPa,which indicates that the oil pressure of the wellhead and pump can be effectively decreased,the overall construction displacement is en-hanced,and the goal of increasing injection pressure reduction is achieved.