超临界二氧化碳粒子射流破岩性能分析

Analysis on rock-breaking property of supercritical carbon dioxide particles jet

由于页岩和致密砂岩等非常规储层岩石的破岩门限压力大,为充分发挥超临界二氧化碳在开发非常规资源方面的技术优势,提出引入粒子后形成超临界二氧化碳粒子射流,提高射流的破岩效率。在优化超临界二氧化碳射流破岩实验流程的基础上,研制超临界二氧化碳粒子射流破岩实验装置,分析超临界二氧化碳粒子射流的破岩性能。结果表明:相对于纯超临界二氧化碳射流,加入石英砂30 s后超临界二氧化碳粒子射流的破岩性能得到大幅度增强,破岩体积提高了66.67%;超临界二氧化碳粒子射流的破岩性能随着喷嘴直径和喷距的增大先增强后减弱;本试验条件下最优喷嘴直径为3 mm、喷距为6 mm,粒径为0.3～0.5 mm;压力和温度越高,射流的破岩性能越强,但增强的趋势逐渐变缓。

Because the rock-breaking threshold pressure of most unconventional reservoir rocks such as shale and tight sandstone are very high, the supercritical carbon dioxide particles jet are formed by adding the particles into jet in order to improve the rock-breaking efficiency and take full advantage of supercritical carbon dioxide. On the basis of the optimization of the supercritical carbon dioxide jet rock-breaking experimental process, a supercritical carbon dioxide particles jet rock-breaking experimental device was built, and the rock-breaking property of the supercritical carbon dioxide particles jet was analyzed. It is found that the rock-breaking property of the supercritical carbon dioxide particles jet is greatly enhanced by 66.67% after adding quartz particles in 30 s compared with the pure supercritical carbon dioxide jet. Also, the rock-breaking property of supercritical carbon dioxide particles jet first enhances and then weakens with the increase of nozzle diameter and standoff distance. It is determined that the optimal nozzle diameter is 3 mm, standoff distance is 6 mm and quartz sand with particle size is 0.3-0.5 mm, which are determined under the experimental condition. The higher the jet pressure and temperature is, the stronger the rock-breaking property of the jet will be obtained. However, the increasing trend slows down gradually.