适用于修井液污染的新型解堵增产液体系研究

New Plug Removal and Stimulation System Suitable for Workover Pollution

针对海上某油田修井作业后出现油井产能下降的现象,开展了储层污染原因的分析,结果认为现场用修井液与地层流体的不配伍是造成储层污染的主要原因。为此,室内研究出了一套适合修井污染后的新型解堵增产液体系,并对体系的综合性能进行了评价。结果表明,新型解堵增产液体系对无机垢具有较好的溶解能力,与地层流体配伍性较好,对油管的腐蚀较小。注入2 PV新型解堵增产液后,岩心驱替的渗透率恢复值可以达到115%左右,说明研究的新型解堵增产液体系不但能够解除前期修井过程中带来的储层污染,同时对储层具有一定的改善作用,综合体现出对油井具有很好的解堵增产效果。现场应用结果表明,在常用修井液修井作业后,表皮系数均大于0,使用研制的新型解堵增产液进行解堵,表皮系数大幅降低,比采油指数和日产油量大幅增加,效果优于常规酸化解堵液。

In view of the decline of oil productivity after workover operation,the causes of reservoir pollution are analyzed.The results show that the incompatibility between workover fluid and formation fluid is the main cause of reservoir pollution.Therefore,a new type of plug removal and stimulation fluid system suitable for polluted workover wells has been developed and its comprehensive performance has been evaluated.The research results show that the solution of plug removal and stimulation system has better ability to dissolve inorganic scale,and has better compatibility with formation fluid and less corrosion of oil pipe.The permeability recovery of core flooding can reach about 115%after injection of 2PV solution of plug removal and stimulation fluid,which shows that the solution of plug removal and stimulation fluid can not only remove the reservoir pollution caused by the work-over process,but also improve the reservoir to some extent.Comprehensive reflect has blocking stimulation effect of a good solution to the oil well.The field application results show that after the workover operation,the skin plugging coefficient is greatly reduced by using the optimized plugging and stimulation fluid.The skin factor is significantly increased,and the effect is better than the conventional acidizing plugging solution.