用返排液作基液的压裂液配方研究

Study on Formulating Fracturing Fluids with Used Fracturing Fluids for Tight Gas Reservoirs

为解决压裂返排处理水重复利用的问题,探讨了压裂返排处理水对胍胶压裂液的影响。针对胍胶压裂液在高矿化度水中溶胀和交联效果差的难题,通过优选耐盐胍胶PA-G、研制螯合调节剂PA-CR以及合成有机硼交联剂PA-CL,优化出一套适应于压裂返排处理水重复配制压裂液的配方。实验表明该配方可满足90℃耐温耐剪切要求,具有以下功能:①优选的耐盐胍胶PA-G溶胀速度快,黏度高,0.3%含量下5 min即可达到30 mPa·s;②研制的高效螯合调节剂,由有机碱、EDTA、有机膦酸盐和聚合物组成,可有效螯合钙、镁离子,可将含1500 mg/L钙镁离子高矿化度水的pH值调节至10以上时不发生沉淀;③研制的有机硼交联剂具有延迟交联功能。

In this paper, the effects of the water from the treatment of the flowback fracturing fluids on the properties of the guar gum fracturing fluid were discussed to solve the problem of the reuse of the water. In high salinity water, guar gum has poor swelling capacity and poor crosslinking performance. To overcome these problems, a salt-resistant guar gum PA-G, a chelating agent PA-CR and a synthesized organoboron crosslinking agent PA-CL were used to formulate a fracturing fluid with water from flowback fracturing fluids. Laboratory experimental results showed that this fracturing fluid is resistant to shearing damage at 90 ℃. It has these functionalities such as: 1) the selected salt-resistant guar gum PA-G has high swelling rate and high viscosity;water solution containing 0.3% PA-G has its viscosity developed to 30 mPa·s in 5 min. 2) The high efficiency chelating agent, which was developed with organic base, EDTA, organophosphate and polymer, can effectively chelate calcium and magnesium ions. Using this chelating agent, the pH of a high salinity water containing 1,500 mg/L calcium and magnesium ions can be raised to above 10 without causing precipitation. 3) the organoboron crosslinking agent developed has the property of delaying crosslinking.