摘要
超临界二氧化碳(SC-CO2)压裂是一种新型的无水压裂技术,对页岩储层的保护及改造效果的提升都具有重要意义.本文基于一系列页岩压裂试验结果,总结了页岩的超临界二氧化碳压裂特点,分析了二氧化碳黏度性质及相变过程中的能量变化对压裂的影响,揭示了超临界二氧化碳压裂页岩的机理,并与常规的水力压裂技术进行对比,阐明超临界二氧化碳压裂技术的优势.研究表明,超临界二氧化碳压裂页岩的破裂压力比水力压裂小,形成的页岩裂缝具有"单向扩展时宽度大,分散扩展时密度高"的特点,并且具有绿色发展的优势.研究结果对于深入了解超临界二氧化碳压裂页岩的机理和优势具有重要意义,为页岩储层的压裂改造实现绿色发展提供参考.
Abstract
Supercritical carbon dioxide(CO2)is a promising non-aqueous fracturing fluid compared to the water regular-ly used in hydraulic fracturing operations.It has great potential for improving shale reservoir production.In this study,the characteristics of supercritical CO2 fracturing were summarized,and the effects of CO2 viscosity and energy changes on fracturing were analyzed.Additionally,the advantages of supercritical CO2 fracturing compared to water fracturing were revealed.The results show that supercritical CO2 fracturing has the advantages of sustainability and high efficiency.All shale specimens fractured by supercritical CO2 show smaller breakdown pressure.The shale fractures induced by su-percritical CO2 have the characteristics of simple but larger width,thin but complex.These results are of great signifi-cance for understanding the mechanism and advantages of supercritical carbon dioxide fracturing and provide references for the green development of shale reservoir fracturing.
维普
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