自生热体系对压裂液破胶性能的影响*

Effect of Autogenous Heat Generation System on Gel Breaking Performance of Fracturing Fluid

沈秀伦 蒋官澄 李新亮 甄延忠 崔凯潇 李武泉

SHEN Xiulun JIANG Guancheng LI Xinliang ZHEN Yanzhong CUI Kaixiao LI Wuquan

针对浅层低温油气井压裂后压裂液破胶不彻底、返排率低的问题，优选了亚硝酸盐与铵盐、三氧化铬和葡 萄糖、过氧化氢3种自生热体系的最佳反应参数，分析了3种自生热体系的生热量以及对压裂液破胶性能的影 响。结果表明，硝酸盐与铵盐自生热体系的最佳反应参数为激活剂HCl浓度2 mol/L，生热剂NaNO2和NH4Cl（物 质的量比1∶1）浓度为8 mol/L；三氧化铬和葡萄糖自生热体系的最佳反应参数为激活剂HCl浓度1 mol/L，生热剂 CrO3和C6H12O6（质量比1∶1）加量为14%；过氧化氢自生热体系的最佳反应参数为激活剂MnO2加量0.3%，生热剂 H2O2加量为30%。过氧化氢自生热体系的生热量最高，温度可达到91 ℃。在压裂液破胶实验中，葡萄糖和三氧 化铬自生热体系和破胶剂过硫酸铵的加入顺序对压裂液的破胶效果无影响，过氧化氢自生热体系应和破胶剂同 时加入，亚硝酸盐与铵盐自生热体系的加入顺序为先加入自生热体系后加入破胶剂。亚硝酸盐与铵盐自生热体 系是压裂液破胶体系的最佳添加剂，可使压裂液黏度降至6 mPa·s以下，破胶性能最优。

Aiming at the problems of incomplete gel breaking and low flowback rate of fracturing fluid after fracturing in shallow low-temperature oil and gas well，the optimum reaction parameters of three autogenous heat generation systems，including nitrite and ammonium salt，chromium trioxide and glucose，and hydrogen peroxide were selected. Under the reaction parameters，the heat generation of three systems and their influence on gel breaking performance of fracturing fluid were analyzed. The results showed that the best reaction parameter for nitrate and ammonium salt system was obtained as follows：2 mol/L activator HCl，8 mol/L heat generating agent NaNO2 and NH4Cl（molar ratio 1∶1）. That for chromium trioxide and glucose system was obtained as follows：1mol/L activator HCl，14% heat generating agent CrO3 and C6H12O6（mass ratio 1∶1）. That for hydrogen peroxide system was obtained as follows：0.3% activator MnO2，30% heat generating agent H2O2. Hydrogen peroxide system had the highest heat generation，and the temperature could reach 91 ℃. In the gel breaking experiment of fracturing fluid，the adding sequence of glucose and chromium trioxide system and gel breaker ammonium persulfate had no influence on gel breaking effect of fracturing fluid. The hydrogen peroxide system should be added with gel breaker at the same time. However，for the nitrite and ammonium salt system，the gel breaker was added after the heat generation system. The nitrite and ammonium salt system was the best additive for gel breaking system of fracturing fluid and had the best gel breaking performance，which could reduce the viscosity of fracturing fluid to less than 6 mPa·s.

10.19346/j.cnki.1000-4092.2021.04.009