超临界二氧化碳喷射破碎页岩试验

高效开发页岩气有利于满足日益增长的能源需求，但页岩储层的开发极为困难，超临界二氧化碳作为一种新型页岩气钻采流体，可以有效保护页岩储层，置换吸附提高页岩气采收率，并同时实现二氧化碳的埋存.研发了一套超临界二氧化碳喷射开发页岩气装置，并开展了超临界二氧化碳喷射破碎页岩室内试验.发现超临界二氧化碳射流喷射后岩石强度降低，且射流压力和温度越高，降低幅度越大；本实验条件下超临界二氧化碳射流破岩体积是水射流的1.73~6.51倍，破岩优势显著，井底环境温度对超临界二氧化碳射流的破岩性能有较大影响.表明超临界二氧化碳可显著提高页岩气钻井速度，有望形成一种高效的页岩气开发方法，应用潜力广阔. 

Experiment of Breaking Shale Using Supercritical Carbon Dioxide Jet

The efficient development of shale gas with abundant resources is conducive to meeting the growing energy demand. However, it is very difficult to develop shale reservoirs because of their low porosity and low permeability in China. Supercritical carbon dioxide is a new kind of drilling and production fluid for shale gas which can effectively protect shale reservoirs, enhance shale gas recovery by displacement adsorption, and realize the geological storage of carbon dioxide. A set of device for developing shale gas by using supercritical carbon dioxide is developed, and the laboratory tests were carried out. Tests show that the rock strength decreases after the injection of supercritical carbon dioxide, and the higher the injection pressure and temperature, the greater the decreasing range. Under the experimental conditions, the rock-breaking volume of supercritical carbon dioxide jet is 1.73-6.51 times that of water jet, and the rock-breaking advantage is remarkable. The bottom ambient temperature has great influence on rock-breaking performance of supercritical carbon dioxide jet. It shows that the supercritical carbon dioxide can significantly improve the drilling speed of shale gas, and is expected to form an efficient shale gas development method with broad application potential.