油水井酸化作业返排液处理技术

Treatment technology of flowback fluid from the acidizing in oil well and injection well

油井、注水井酸化作业返排液成分复杂,处理难度大。提出在井口就地处理就地回注的思路。对11口油井、注水井酸化返排液进行了分析,确定了沉降预分离-多功能处理系统-多级过滤工艺,优选了中和剂、氧化剂、絮凝剂和污泥浓缩剂,研制了撬装处理设备,现场实施15井次,处理后废液达到油田回注标准:pH值为6～8,含油和悬浮物质量浓度均低于10 mg/L,实现了就地回注。

The flowback fluid from the acidizing in oil well and injection well was difficult to be treated due to its complex components. In this study, on-site treatment was proposed and achieved near the wellhead. A treatment process of “sedimentation-multifunctional system-filtration” was designed on the basis of analyzing flowback fluid samples from 11 oil wells and injection wells. Besides, the neutralization agent, oxidant, flocculants and sludge conditioners were optimized for the field tests. Finally, a skid-mounted treatment equipment was developed and further applied in the following field tests for 15 times. The treated flowback fluid could meet the oilfield reinjection requirements (pH 6-8, oil contents<10 mg/L, and SS<10 mg/L), and on-site reinjection was realized.