二类油层注聚合物井复合解堵体系的研制与应用

Development and application of composite plugging removal system in polymer injection wells of class II reservoir

针对二类油层注聚合物井注入压力高、欠注问题严重的现象,开展了该类井复合解堵体系的研制与应用。在对返排物进行成分分析的基础上,确定了相应的复合解堵体系,并对其降解性能、配伍性能等进行评价,得出该体系由降解剂和复合酸组成。由室内实验可知,该复合解堵体系对二类油层注聚合物井返排物具有较好的溶解效果,其溶解率大于98%。同时,利用该复合解堵体系对现场124口注聚合物井进行试验,措施有效率为85. 5%,平均有效期达170天。该体系对二类油层注聚合物井起到了较好的降压增注效果,更大可能地保证注聚合物井的正常注入。

Due to the class II oil reservoir featured with high polymer injection pressure and severe under-injection phenomenon,the development and application of composite plugging removal system have been conducted.On the basis of analyzing the component of flowback fluid,the corresponding composite plugging removal system has been determined,whose degradation performance and compatibility performance have been evaluated as well.It is indicated that the system is composed of degradation agent and complex acid.Indoor test showed that the composite plugging removal system has favorable dissolution effect to the flowback fluid in polymer injection wells of the class II oil reservoir with dissolution rate being higher than 98%.Meanwhile,the composite plugging removal system has been applied in 124 polymer injection wells with the treatment effectiveness of 85.5%and the average validity being up to 170 days.The system can lower the pressure and increase the injection volume in polymer injection wells of class II oil reservoir,which keeps the normal polymer injection as much as possible.