压裂用胶囊破胶剂性能评价方法研究

胶囊破胶剂主要应用于压裂施工中,起到延迟破胶的作用。现行胶囊破胶剂的评价方法仅采用机械压力将胶囊压碎,然后评价破胶能力,缺乏在地层压力和温度条件下对胶囊提前破裂释放出破胶剂情况的研究,难以对胶囊破胶剂的性能做出准确评价。基于此,本研究利用电导率仪对胶囊破胶剂的受热释放性进行研究；利用高温高压稠化仪模拟地层压力和温度,考查加入胶囊破胶剂的压裂液在高温高压条件下胶囊破胶剂对压裂液黏度的影响；利用扫描电子显微镜对热处理后的样品进行微观形貌分析。通过此3种方法对胶囊破胶剂的性能进行评价。研究发现:使用电导率仪对溶液电导率变化趋势测定,可反映胶囊破胶剂在溶液中的受热释放性能；使用高温高压稠化仪模拟地层工作条件,可评价胶囊破胶剂在高温高压条件下的破胶性能；使用扫描电子显微镜(SEM)观察胶囊破胶剂的微观结构,可反映胶囊破胶剂在高温下作用后包裹囊衣的受热变化情况。

Research on performance evaluation method of capsule breaker for fracturing

Capsule breakers are mainly used in fracturing construction to delay gel breakage. For the current evaluation method of capsule breaker, only mechanical pressure is used to crush it to evaluate its breaking ability. It is difficult to evaluate the performance of the gel breaker accurately because of the lack of research on the condition of release of gel breaker under formation pressure and temperature. Based on this, the thermal release of the capsule breaker and the effect of the capsule breaker on the viscosity of the fracturing fluid under high temperature and high pressure were studied by a conductivity meter and a thickening meter. The scanning electron microscope (SEM) was used to analyze the microstructure of the samples after heat treatment. Through these three methods, the working performance of the capsule breaker can be evaluated. It was found that the thermal release performance of the capsule breaker in solution could be reflected by measuring the change trend of solution conductivity with conductivity meter. The high temperature and high pressure thickener is used to simulate the working conditions of the formation, and the breaking performance of the capsule breaker in the high temperature and high pressure condition is evaluated. Scanning electron microscope was used to observe the microstructure of the capsule breaker, which could reflect the change of the capsule breaker when it was heated at high temperature.