首页|超临界CO2脉动压裂-渗流耦合试验系统研制与应用

超临界CO2脉动压裂-渗流耦合试验系统研制与应用

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  • 国家科技期刊平台
  • NETL
  • NSTL
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[目的]为了有效强化煤层气抽采效果，将脉动压裂与超临界CO2 压裂相结合，提出了利用超临界CO2 脉动压裂煤(岩)的新思路。[方法]自主研发了超临界CO2 脉动压裂-渗流耦合真三轴试验系统，介绍了该试验系统的主要结构、特点和功能，然后开展了室内真三轴条件下超临界CO2 脉动压裂-渗流试验及超临界CO2 脉动压裂-声发射监测试验。该系统结合独立伺服系统与中央数字系统控制三向应力，采用双泵型恒速恒压泵脉动给压，具有高精度、全过程、真三轴、承载高温、高压及高应力的特点。[结果和结论]试验结果表明:超临界CO2 脉动压裂-渗流耦合真三轴试验系统可以实现良好的脉动压裂功能。超临界CO2 脉动压裂后，煤体渗透率较压裂前呈增大趋势，增大了 2～9倍，且煤体渗透率皆呈现良好的指数变化规律。在声发射-超临界CO2 脉动压裂时期，煤体产生了新的裂隙通道，该通道由压裂孔中心直接贯穿至煤样表面，且可观测到超临界CO2 流体直接从煤中喷出，故超临界CO2 脉动压裂具有一定的扩展和连通裂隙的作用，能够有效提高煤层气的抽采效果。研究成果为强化深部低渗煤层增透技术提供了一定的试验支撑。
Development and application of a supercritical CO2 pulsed fracturing-seepage coupling test system
[Objective]To effectively enhance the extraction effects of coalbed methane(CBM),this study proposed a novel approach for fracturing coals(rocks)using pulsation of supercritical carbon dioxide(CO2)by combining pulsed fracturing with supercritical CO2 fracturing.[Methods]A true triaxial test system coupling supercritical CO2 pulsed frac-turing with seepage was independently developed,and its primary structure,characteristics,and functions were elucid-ated.Then,the supercritical CO2 pulsed fracturing-seepage/acoustic emission monitoring tests under true triaxial condi-tions were conducted in the laboratory.The test system,controlling the triaxial stress by combining an independent servo system with a central digital system and achieving pulsed pressurization using a dual pump with constant speed and pres-sure,features high precision,true triaxiality,and resistance to high temperature,pressure,and stress and covers the whole process.[Results and Conclusions]The results indicate that the true triaxial test system that couples supercritical CO2 pulsed fracturing with seepage can achieve effective pulsed fracturing.Using supercritical CO2 pulsed fracturing,the permeability of coals can increase by two to nine times,manifesting a pronounced exponential growth.During the acoustic emission-supercritical CO2 pulsed fracturing,new fracture channels were formed in coals.These channels pen-etrated directly from the center of the fractured pores to the coal surface,with supercritical CO2 being observed ejecting directly from coals.Therefore,supercritical CO2 pulsed fracturing plays a certain role in propagating and connecting fractures,effectively improving CBM extraction.The findings of this study provide certain test support for reinforcing the permeability enhancement technology of deep,low-permeability coal seams and offer practical guidance for field CO2 fracturing engineering.

supercritical CO2pulsed fracturingtrue triaxialityseepage characteristicacoustic emission

刘佳佳、张云龙、聂子硕、高志扬、许文松

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河南理工大学 安全科学与工程学院,河南 焦作 454003

安徽理工大学 深部煤矿采动响应与灾害防控国家重点实验室,安徽 淮南 232001

河南理工大学 煤炭安全生产与清洁高效利用省部共建协同创新中心,河南 焦作 454003

瓦斯灾害监控与应急技术国家重点实验室,重庆 400037

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超临界CO2 脉动压裂 真三轴 渗流特性 声发射

国家自然科学基金面上项目河南省优秀青年科学基金河南理工大学创新型科研团队项目深部煤矿采动响应与灾害防控国家重点实验室开放基金瓦斯灾害监控与应急技术国家重点实验室开放基金

52074106232300421061T2023-3SKLMRDPC22KF112021SKLKF01

2024

10.12363/issn.1001-1986.23.11.0773

煤田地质与勘探
中煤科工集团西安研究院

煤田地质与勘探

CSTPCD北大核心
影响因子：1.079
ISSN：1001-1986
年,卷(期)：2024.52(6)
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