植物胶压裂液循环利用的制约因素分析

Analysis of Factors Restricting Cyclic Utilization of Plant Gum Fracturing Fluid

为实现压裂液的循环利用,节约水资源,减少环境污染,研究了植物胶压裂液返排液中残余交联剂硼和稠化剂对循环利用的影响。以均相状态为评价标准,采用拉曼光谱测定不同多羟基化合物与硼交联剂的结合形态,对体系中残余交联剂硼的最小无作用量进行研究;测定了破胶过程中稠化剂的相对分子质量、总糖含量和pH值的变化。结果表明,破胶液内部残留的交联剂和稠化剂均为制约返排液循环利用的制约因子。硼砂-甘露醇络合性能稳定,甘露醇可作为高效掩蔽剂,交联剂硼的最小无作用量为5 mg/L;过硫酸盐破胶时可以将稠化剂胍胶大分子部分降解,随破胶时间延长,小分子比例增加,体系中总糖含量下降。溶剂总糖含量低于1800 mg/L时所配制的压裂液可以满足循环利用要求,但残渣伤害风险增加。

In order to save water resources,reduce pollution and realize the recycling of fracturing fluid,the influence of residual crosslinking agent and thickener in the flowback fluid of vegetable gum fracturing fluid on the recycling was studied.Based on the standard that the system is homogeneous,raman spectroscopy was used to determine the binding forms of different polyhydroxy compounds with boron.The minimum non action amount of residual crosslinking agent boron in the system was studied.The molecular weight,total sugar content and pH value of thickener were determined.The results showed that the residual crosslinking agent and thickener are sensitive factors restricting the recycle of flowback liquid.The performance of borax mannitol complex was stable,indicating that mannitol could be used as a high-efficiency masking agent,and the minimum amount of boron without action was less than 5 mg/L.Persulfate gel breaking could partially degrade the large molecules of guar gum.With the extension of gel breaking time,the proportion of small molecules increased,and the total sugar content in the system decreased.it was found that when the total sugar content in the system was less than 1800 mg/L,the fracturing fluid could meet the requirements of cyclic utilization,but the risk of residue damage increased.