苏里格气田压裂返排液回收处理方法

Recovery and treatment of fracturing flowback fluids in the Sulige Gasfield,Ordos Basin

为了实现气田高效经济开发,对鄂尔多斯盆地苏里格气田低渗透致密砂岩气藏采用了集群化布井和工厂化压裂技术,但井组集中压裂会导致作业现场短期内排液量急剧增加,环境保护形势严峻。为此,针对该气田压裂试气作业的特点,并结合其地形地貌特征等因素,研究形成了适合于苏里格气田的压裂返排液回收处理方法:①就井间压裂液回收再利用方面,形成了以多效表面活性聚合物可回收压裂液体系为核心的高效井间压裂返排液回收再利用技术,解决了常规胍胶压裂液体系处理效率低的难题;②针对井场末端液体回收处理难题,形成了以"混凝沉淀、过滤杀菌、污泥脱水"为主体的压裂返排液精细回收处理技术。该压裂返排液回收处理方法提高了现场水资源的利用率,并缓解了作业环保压力。2014年现场试验10个井组62口井,累计回收处理返排液32 980 m^3,其中实现重复利用17 160 m^3,回收再利用率超过70%,取得了显著的社会经济效益。

Centralized and group well deployment and factory-like fracturing techniques are adopted for low-permeability tight sand- stone gas reservoirs in the Sulige Gasfield, Ordos Basin, so as to realize its efficient and economic development. However, environ- mental protection is faced with grim situations because fluid delivery rises abruptly on site in a short time due to centralized fracturing of the well group. Based on the characteristics of gas testing after fracturing in this gas field, this a fracturing flowback fluid recovery and treatment method suitable for the Sulige Gasfield was developed with the landform features of this area taken into account. First- ly, a high-efficiency well-to-well fracturing flowback fluid recovery and reutilization technique was developed with multi-effect surfac- rant polymer recoverable fracturing fluid system as the core, and in virtue of this technique, the treatment efficiency of conventional guar gum fracturing fluid systems is increased. Secondly, for recovering and treating the end fluids on the well sites, a fine fracturing flowback fluid recovery and treatment technique was worked out with “coagulation and precipitation, filtration and disinfection, and sludge dewatering” as the main part. Owing to the application of this method, the on site water resource utilization ratio was in- creased and environmental protection pressure concerned with fracturing operation was relieved. In 2014, field tests were performed in 62 wells of 10 well groups, with 32 980 m3 cumulative treated flowback fluid, 17 160 ma reutilization volume and reutilization rati o over 70% Obviously, remarkable social and economical benefits are thus realized.