注水井循环洗井技术研究

A Research on Circular Water Injection Well Flushing Techniques

注水井洗井可以清除井筒内的聚集物,减少炮眼附近油层污染。常规罐车拉运洗井方式难以满足大庆油田外围采油厂距离废液处理站远及无洗井流程的注水井洗井需要。进行注水井循环洗井技术研究,根据Hazen"浅池理论"和斯托克斯理论,设计出无动力油水分离系统。该系统工艺结构合理,布局紧凑,通过多级机械塔板的缓冲沉降,实现油水及杂质的无动力分离,适用于注水井洗井工作需要。无动力油水分离系统与加药技术和精细过滤技术合为一体,在洗井水流经无动力油水分离器时,启动加药系统,向污水中加入优选的杀菌药剂,实现油水的分离、杀菌及絮凝。处理后的洗井液通过精细过滤器的二次过滤,达到标准后回注到井内,实现注水井的循环洗井。注水井循环洗井技术克服了常规洗井方式存在的污染环境、耗资大的问题,符合绿色油田的发展需要,具有广阔的应用前景。

Flushing a water injection well can remove the objects accumulating in the wellbore and reduce oil formation contamination around the borehole.The conventional tanker-based well flushing method is unable to satisfy the need for flushing water injection wells from oil recovery plants on the periphery of the Daqing Oilfield,whieh are far from effluent treatment stations and have no well flushing processes.In a study on cir- cular water injection well flushing techniques,researchers designed a motorless oil and water separating system based on the Hazen shallow pool theory and the Stokes theory.The system,with a well designed and compact process structure ,separates oil ,water and impurities without relying on power,by means of the buffering and sedimentation through multi-stage mechanical column plates.The system is suitable for use for flushing water injection wells.The motorless oil and water separating system works together with chemical feeding and fine filtering techniques.When flushing water flows through the motorless oil and water separator,the chemical adding system is initiated and select disinfection chemicals are added into the sewage to achieve separation of oil from water,disinfection and flocculation.Treated flushing fluid is injected back into the wellbore after being filtered again by a fine filter,thus achieving circular flushing for the water injection well.Circular flush- ing technology for water injection wells is free of the defects inherent in conventional well flushing methods, namely environmental pollution and high capital investment,and therefore meets the need for developing green oilfields.This technology has sound market prospect.