摘要：

吴起（WQ）油田压裂返排液存在排放量大、黏度大、处理难等问题，环保形势异常严峻。结合油田开发实际，分析压裂返排液的主要成分，对其重复配液回用性能的影响因素及应对其影响的处理方法进行系统研究。结果表明，Na⁺、K⁺、SO₄ ^2-浓度对基液黏度影响比较小，而Ca²⁺、Mg²⁺及总铁浓度带来的影响比较大，利用Pearson相关系数法确定了离子影响因素排序为总铁含量>Ca²⁺>Mg²⁺>K⁺>Na⁺>SO₄ ^2-；残余交联剂浓度、破胶剂浓度、细菌含量、pH对基液黏度也有一定影响，需要进行适当处理。基于影响因素分析结果，分别采用化学反应、纳米活性炭吸附、紫外灯或太阳光照射、添加氢氧化钠等方法对压裂返排液进行处理，创新性地提出一套“气浮除油-氧化破胶和阳离子去除-混凝脱稳-板框压滤-水质净化”就地处理工艺，经该工艺处理后的压裂返排液用于配制新的压裂液，能够满足现场需求，应用效果较好，实现了压裂返排液的循环利用，达到了清洁生产和节约成本的目的。

关键词: 压裂返排液, 压裂液性能, 循环利用, 清洁生产

Abstract:

The fracturing backflow fluid in Wuqi(WQ) Oilfield has problems such as large quantity, high viscosity, and difficult treatment, and the environmental situation is extremely severe. Combined with the actual oilfield development, the main components of fracturing backflow fluid were analyzed, and the factors affecting the reuse of fracturing fluid and the treatment methods to deal with the impact were studied systematically. The results showed that the concentrations of Na⁺, K⁺ and SO₄ ^2- had a little influence on the viscosity of base fluid, while Ca²⁺, Mg²⁺ and total iron concentrations had greater influence. The order of ion influencing factors was as follows: Total iron>Ca²⁺>Mg²⁺>K⁺>Na⁺>SO₄ ^2-. Residual cross-linking agent concentration, gel breaker concentration, bacterial content and pH also had great influence on the viscosity of base liquid. Based on the results of influencing factors analysis, the backflow was treated by chemical reaction, nano-activated carbon absorption, UV lamp or sunlight, and sodium hydroxide addition. On this basis, a set of in-situ treatment process of “oil removal by air flotation-oxidation gel breaking and cation removal-coagulation destabilization-plate frame pressure filtration-water purification” was formed. The fracturing flowback fluid treated by this process was used to prepare new fracturing fluid, which could meet the needs of the field, and the application effect was good. The recycling of the backflow liquid was realized, and the purpose of cleaner production and cost saving was achieved.

Key words: fracturing flowback fluid, fracturing fluid performance, recycling, cleaner production

中图分类号: 

• TQ314.2