低渗透油田注水井不返排酸化技术研究

Research on non-flowback acidizing technology in water injection wells of low permeability oilfield

针对常规酸化施工后,残酸返排施工、处理和运输均存在安全环保隐患问题,开展了不返排酸化工艺技术研究。通过溶蚀性能、络合性能和腐蚀性能评价,以及岩心驱替实验,优选配方体系;采用多段塞组合的方式优化施工工艺。现场试验70口井,结果显示,初期平均单井注水压力下降1. 7MPa,日增注量为17. 4m^3。注水井不返排酸化技术取得与常规酸化相同增注效果的同时,实现酸化施工后不返排直接恢复注水,减少残酸产生,在绿色环保施工方面具有较好的推广应用前景。

The conventional acidizing operation needs to discharge the residual acid from borehole,which exists potential danger in safety and environment protection during the dispose and transportation procedures,therefore,the research on non-flowback acidizing technology has been conducted.Through the property evaluation of dissolution,complexation and corrosion,as well as core displacement test,the formula system has been optimized.The combination of multi-slug is adopted to optimize the operation technology.It has been applied to 70 wells,and the injection pressure per average single well dropped by 1.7MPa initially,and the daily injection volume increased by 17.4m3.While obtaining the same stimulation effect as the conventional acidizing technology,the non-flowback acidizing technology in water injection has no need of discharging the residual acid and water injection can be resumed immediately so as to reduce the flowback of waste acid.The new technology has better prospect of promotion and application in green environmental protection operation.