页岩气储层无水压裂技术现状

Status quo of water-free fracturing technology for shale gas reservoirs

国内外页岩气开采主要是采用水力压裂技术,由于水力压裂技术存在水资源消耗大、储层伤害严重、水环境污染等问题,近年来无水或者少水压裂技术因其能有效避免页岩水锁效应、降低储层伤害越来越受到关注。为了减少非常规储层改造过程中水资源的消耗、降低环境风险,对页岩气无水压裂技术进行了系统调研,通过采用调查、对比分析以及实例论证等方法,对水力压裂、超临界CO_(2)等无水压裂、泡沫压裂技术实施特征以及优势与劣势进行了总结和分析,并对未来压裂技术的发展方向进行了探讨与展望。研究结果表明:(1)目前无水压裂技术主要包括液态CO_(2)压裂技术,超临界CO_(2)压裂技术,液态N2压裂技术,液化石油气(LPG)压裂技术以及泡沫压裂技术。这些技术具有与储层流体配伍性好、造缝能力强、增产效果好等特点;(2)泡沫压裂液具有良好的支撑剂承载能力和支撑剂输送能力,从而可使支撑剂更有效地遍布整个裂隙网络;(3)在我国“碳达峰碳中和”战略背景下,CO_(2)压裂技术可实现CO_(2)的资源化利用和地质封存,可在进行压裂技术选择的时候对其CO_(2)减排效应进行综合考虑。

Hydraulic fracturing technology is the main technology for shale gas production at home and abroad,but it faces the challenges of great water consumption,serious reservoir damage and water environment pollution.Water-free or low-water fracturing technology has attracted more and more attention in recent years for it can effectively avoid shale water lock effect and reduce reservoir damage.In order to reduce the consumption of water resources in the process of unconventional reservoir stimulation and diminish environmental risks,this paper systematically investigates the shale gas water-free fracturing technology.Then,the implementation characteristics,advantages and disadvantages of hydraulic fracturing,water-free fracturing(e.g.supercritical CO_(2)fracturing)and foam fracturing technologies are summarized and analyzed by means of investigation,comparative analysis and case demonstration.Finally,the development directions of future fracturing technologies are discussed and forecast.And the following research results are obtained.First,the current water-free fracturing fluid technologies mainly include liquid CO_(2)and N2fracturing fluid technology,supercritical CO_(2)fracturing fluid technology,LPG(liquefied petroleum gas)fracturing fluid technology,and alcohol based fracturing fluid technology,all of which are characterized by good compatibility with reservoir fluid,strong fracture making ability and good stimulation effect.Second,foam fracturing fluid has good proppant bearing capacity and proppant transportation capacity,so that proppant can be distributed throughout the fracture network more effectively.Third,under the strategic background of"carbon peaking and carbon neutrality"in China,CO_(2)fracturing technology can realize the resource utilization and geological storage of CO_(2).When selecting fracturing technology,CO_(2)emission reduction effect shall be considered comprehensively.