压裂液低温破胶化学生热体系的探讨

Discussion on the chemical heat-generating system for gel-breaking at low temperature

针对目前压裂液低温破胶存在的问题 ,着重研究了适合于低温浅层油气井压裂液破胶的化学生热体系 ,提出一种微胶囊包裹化学生热剂压裂液破胶方法 .阐述了不同生热体系的生热反应速率及其影响因素 ,并通过对不同生热体系的研究 ,筛选出了 NH4Cl和 Na NO2 作为低温压裂液破胶体系的生热体系 .实验结果表明 :在 1 70 1 /s下连续剪切 2 h后 ,含有 NH4Cl— Na NO2 的压裂液黏度能保持在 5 0 0 m Pa· s左右 ,满足压裂施工时的压裂液性能要求 ;将催化剂、过硫酸铵、NH4Cl和Na NO2 加到压裂液中 ,4h后压裂液即可完全破胶 ,其破胶液黏度小于 1 0 m Pa·

In order to solve the problem of gel-breaking of the fracturing fluid for low temperature shallow oil and gas wells, an approach to fracturing fluid gel-breaking is proposed, that is, the chemical heat-generating agent packed by microcapsule is injected into formation together with fracturing fluid, definite time later, the heat-generating agent generates a lot of heat by chemical reaction, the fluid in fractures is heated, and the gel-breaking of fracturing fluid is taken place. The heat-generating rates of different heat-generating systems and their influencing factors are discussed in order to select out the best heat-generating system. The ammonium chloride--natrium nitrosum heat-generating system is chosen out at last. The shearing experiments show the heat-generating system has good compatibility with boron cross-linked HPG fracturing fluid, and the rheological property of the fracturing fluid system can meet the requirements of carrying propping agent.