高pH值强溶型直排酸解堵体系的研究及应用

Research and application of high pH and strong corrosion directly discharged acid plugging removal system

针对海上油田油井解堵面临的常规酸化残酸返排和螯合中性解堵体系在部分井况实施效果不理想这2个问题,采用弱酸弱碱盐、电离可逆平衡的思路,研发了一种高pH值强溶型直排酸解堵体系。综合性能表明,体系原液pH≥3,残酸pH≥5,同时具有常规酸液溶蚀性能,可实现对钙垢、铁垢和黏土垢的溶解,同时还具有优良的破乳、缓速、稳铁以及动态驱替性能。体系在海上油田开展了3井次试验应用,增产倍比达1.38~2.17倍,可以达到常规酸化的措施效果,返排液pH值在5~7,返排液对流程无影响,具有较好的推广应用价值。

The conventional acidizing residual acid backflow problem and the unsatisfactory implementation effect of chelating neutral plugging removal system in some well conditions faced by offshore oilfield oil well plugging removal were two aspects of the problem.One high pH and strong corrosion directly discharged acid plugging removal system has been developed using the concept of weak acid,weak base salt,and reversible ionization equilibrium.The comprehensive performance showed that pH of the original solution of the system was≥3,and pH of the residual acid was≥5.At the same time,it has conventional acid solution corrosion performance,which can achieve the dissolution of calcium scale,iron scale,and clay scale.It also has excellent demulsification,speed inhibition,iron stability,and dynamic displacement performance.This system has been tested and applied three times in offshore oil fields,with an increase in production ratio of 1.38to 2.17times,which can achieve the effect of conventional acidification measures.The pH value of the backflow fluid was between 5and 7,and it has no impact on the process,which has great promotion and application value.