渤海油田注聚受效井解堵技术研究与应用

Research and application of plug removal technology for polymer flooding response well in Bohai oilfield

针对渤海油田注聚受效井日趋严重的聚合物堵塞问题,利用扫描电子显微镜(SEM)、能量色散X线(EDX)、热重分析仪(TGA)对聚合物堵塞物的成分进行分析,研究发现堵塞物主要由聚合物、原油、无机物和黏土矿物等组成。通过注聚受效井产出水、聚合物以及高价金属离子对聚合物性质的影响研究,明确了聚合物堵塞物的形成机制。基于对聚合物堵塞物的认识,针对性开发了一种多功能螯合解聚体系,能够同步实现洗油、溶垢、解聚,并在现场成功应用。实验表明,多功能螯合解聚体系对6种现场注聚受效井聚合物堵塞物的溶蚀率均大于90%,且其腐蚀速率仅为3.60 g/(m2·h),低于行业标准中盐酸、土酸体系的评价指标。现场应用表明,多功能螯合解聚体系具有良好的解堵增产效果,日产油从17 m3上升至55 m3,措施持续有效。

In view of the increasing serious problem of polymer plug in polymer flooding response well in Bohai Oilfield,scanning electron microscopy(SEM),energy dispersive X-ray(EDX),and thermogravimetric analyzer(TGA)was used to analyze the composition of polymer plugs.It was found that the plug was mainly composed of polymers,crude oil,inorganic matter and clay minerals.The formation mechanism of polymer plugs was clarified by studying the effects of produced water,polymer and high-valent metal ions on polymer properties from polymer-response wells.Based on the knowledge of polymer plugs,a multifunctional chelating depolymerization system was developed,which could simultaneously realize oil washing,scale dissolution,and depolymerization.Simultaneously,it had been successfully applied in the Bohai oilfield.The experiments results showed that the corrosion rate of the polymer flooding response wells onsite plugs was more than 90%with multi-functional chelating depolymerization system.Furthermore,the corrosion rate was only 3.60 g/(m².h),which was lower than the evaluation index of hydrochloric acid and soil acid system in the industry standard.Field application demonstrated that the multi-functional chelating depolymerization system had a good effect on plugging removal and increasing production.The daily oil production increased from 17 m'to 55 m',and the measures were continued to be effective.