Abstract: The flowback fluid during oil acidizing operation process would directly enter the gathering and transportation system,resulting in deterioration or invalidation of conventional treatment agents,such as demulsifiers.The flowback fluids from the Chengdao Oilfield were divided into two types ，one is high mass concentration,the other is low mass concentration.The high mass concentration flowback fluid is transported back by the operating ships to the shore for further treatment,and the low mass concentration flowback fluid is directly discharged into the gathering and transportation system under the ground.The flowback cycle is long and affected by sea conditions. In order to reasonably estimate the amount of high mass concentration flowback fluid produced by crude oil dehydration process,this paper analyzes the factors affecting the oil⁃water separation of acidified flowback fluid.The volume of flowback fluid and indicators of water in two acidified oil wells were monitored,and thermal deposition of mixed flowback fluid and crude oil were tested. According to the demulsification effect and the water content of crude oil form the joint station, the quantified critical control index are listed as: the pH value of the water from the acidified oil well is higher than 6, the iron ion concentration is lower than 250 mg/L；and the auxiliary control index: the amount of backflow reaches 6 times higher than that of the acid liquid. An inspection method is proposed for the on⁃site operation of the flowback fluid discharging into the gathering and transportation system, properly reducing the flowback time without adding a new processing flow, which is beneficial to increase the oil well production rate and improve economic efficiency.

Key words: Acidified oil, Demulsification and dehydr ation, Test method； Control indicators, Flowback fluid volume

摘要： 油井酸化作业返排液直接进入集输系统会造成破乳剂等常规处理药剂效果变差或失效，埕岛油田返排液分为高质量浓度和低质量浓度两种。高质量浓度返排液用作业船运回岸上处理，低质量浓度返排液直接进入地面集输系统处理，返排周期长且易受海况影响。为了在现有原油脱水工艺下对高质量浓度返排液量进行合理规划，分析了酸化返排液中影响油水分离的因素，监测2口酸化油井返排液量及水相指标，进行返排液与进站原油混合热沉降对比实验。根据破乳效果和联合站外输原油含水率，量化出关键控制指标为：酸化油井水相pH高于6，铁离子质量浓度低于250 mg/L；辅助控制指标为：返排量达到酸液6倍。形成了易于现场操作的返排液进入集输流程的检验方法，在不增加新的处理流程下适当缩短进入集输系统所用时间，有助于增加油井生产时率，提高经济效益。

关键词: 酸化油, 破乳脱水, 检验方法, 控制指标, 返排液量