弱碱三元复合驱注入井解堵增注工艺技术研究

Study on plugging removal and stimulation technology for injection wells by weak alkali ASP flooding

随着化学驱的规模应用,弱碱三元复合驱成为油田持续有效开发的重要技术。但随着注剂量增加,部分注入井注入压力高、配注困难的问题日益突出,影响了区块的开发效果,因此开展了弱碱三元复合驱注入井解堵增注工艺技术研究。通过室内实验检测分析地层堵塞物成分及堵塞机理,研发了弱碱三元复合驱注入井解堵剂,配套了“降聚—复合酸—共轭酸—保护”段塞式施工工艺,分步实现聚合物降解、储层基质改造、深部解堵及络合保护。段塞间协同作用,实现弱碱三元复合驱注入井深部解堵、零外排。现场应用结果表明,措施后残液无需返排,措施有效率达80%以上,有效期180d以上,实现了低成本绿色环保解堵,将有效支撑弱碱三元复合驱的整体开发效果。

With the scale application of chemical flooding,weak alkali ASP flooding has become an important technology for the sustainable and effective development of oilfield.However,with the increase of injection dose,the problems of high injection pressure and difficult injection allocation in some injection wells have become increasingly prominent,which affects the development effect of block.Therefore,the technology of plugging removal and stimulation for injection wells by weak alkali ASP flooding was studied.Through the laboratory test to analyze the composition and mechanism of blockage,the injection well plugging agent of weak alkali ASP flooding was developed,the slug technology including“polymer degradation,complex acid,conjugated acid and propection process”was matched,and the polymer degradation,reservoir matrix modification,deep plug removal and complexation protection were achieved step-by-step.The synergistic effect between slugs could realize deep plug removal and zero flowback.The field application results showed that there was no need to flow back the residual fluid after the measure,and the effective rate of the measure was over 80%,with period of validity above 180 days,which realized low-cost,green and environmentally friendly plugging removal and effectively supported the overall development effect of weak alkali ASP flooding.