摘要
随着煤矿开采深度增加和难抽采煤层增多,对高瓦斯突出煤层增透技术的要求也不断提高.通过扫描电镜测试、分形维数分析、动态应变测试以及红外热成像分析等现代化分析测试手段,对高压气液两相射流裂纹扩展及致裂机理进行研究.结果表明:在两相射流冲击作用下,煤体裂隙发育明显,孔隙发生破碎并与裂隙相互贯通,煤样按照比表面积计算的分形维数D1平均增加1.98%.在相同射流条件下,煤样直径从2 mm增加到4 mm,周向裂纹出现时的压力阈值从10 MPa增加到了12 MPa.孔隙结构改变及宏观裂纹扩展是高压气相与高压液相共同交互响应的结果.
Coalbed methane(CBM)reservoirs in China are characterized by extremely low aperture and natural fractures density,which seriously affects the efficient CBM exploitation.The fractures development mechanism of coal was experimentally and theoretically studied under high-pressure gas-liquid jet.Experiments were carried out under different jet pressure,target distance and nozzle diameter.Furthermore,we adopt four tests including Scanning Electron Microscope(SEM),fractal dimension analysis,dynamic strain test and infrared thermal imaging to gain a clearer insight into the variations in fractures development.With the increase of fractures,pores are broken and interconnected with fractures under the action of gas-liquid jet.Besides,the dimension D1 calculated by specific surface area increased by an average of 1.98%.With the diameter of coal samples increases from 2 mm to 4 mm,the threshold pressure when circumferential fractures appear increases from 10 MPa to 12 MPa.The interaction between high pressure gas phase and liquid phase improved the development of fractures and structure change of pores.
作者
林柏泉
王正
王瑞
LIN Baiquan;WANG Zheng;WANG Rui(Key Laboratory of Coal Methane and Fire Control,Ministry of Education,State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2020年第1期1-12,共12页
Journal of China University of Mining & Technology
基金
国家重点研发计划项目(2018YFC0807903).
关键词
高压气液
脉动
多级
致裂
high-pressure gas-liquid
pulsation
multistage
fracture development
