Abstract Coal measures are rich in coalbed methane, shale gas and tight sandstone gas, and the three gases co-exploration has become a potentially promising technology in China. During the process of integrated hydraulic fracturing of three gas formations in coal measures, interlayer contradiction occurs due to the formation heterogeneity, which is the key to restricting the application of this technology. In this paper, an experimental device has been designed to study the influencing factors for integrated hydraulic fracturing in coal measure gas reservoir. The results of experimental test and theoretical analysis indicate that the formation permeability and breakdown pressure are the main factors affecting hydraulic fracturing process, and the formations with large difference in these two factors always induce an uneven distribution of fracturing fluid and poor effect of integrated hydraulic fracturing. High flow rate pumping injection rate is conducive to the even distribution of fracturing fluid in various formations. Meanwhile, the proper ball injection is used to limit fluid flowrate to ensure the fluid pressure in high permeability formation is higher than it in low permeability formation, fracturing fluid can flow to low permeability formation through perforation hole. In addition, interlayer crossflow occurs during the migration of fracturing fluid and causes fluid flow to low permeability formation, which is also conducive to the even fracturing. Therefore, high flow rate pumping injection, ball injection and interlayer crossflow control are effective measures for achieving the integrated hydraulic fracturing of coal measure gas reservoirs.

中文翻译：

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煤系气藏综合水力压裂试验研究

摘要 煤系富含煤层气、页岩气和致密砂岩气，三气联合勘探已成为我国具有潜力的技术。煤系三气层综合水力压裂过程中，由于地层非均质性而产生层间矛盾，是制约该技术应用的关键。本文设计了一种实验装置，研究了煤系气藏水力压裂一体化的影响因素。实验测试和理论分析结果表明，地层渗透率和破裂压力是影响水力压裂过程的主要因素，而这两个因素差异较大的地层，往往会导致压裂液分布不均，综合水力压裂效果不佳。高流量抽注量有利于压裂液在各种地层中的均匀分布。同时，通过适当的注球限制流体流量，保证高渗透地层的流体压力高于低渗透地层的流体压力，压裂液可以通过射孔流向低渗透地层。此外，压裂液运移过程中会发生层间错流，使流体流向低渗透地层，也有利于均匀压裂。因此，高流量抽注，