热-力耦合作用下煤岩体渗流特性研究
Study on coal permeability characteristics under thermo-mechanical coupling
-
摘要: 煤层开采深度增加导致地温和应力增大，影响了煤样裂隙发育和渗流特性。为了研究热-力耦合作用下煤岩渗透过程中形变及渗透性变化特征，采用MTS815测试系统测试了50、100 ℃下6组煤样的全应力-应变过程中的渗透性。结果表明：温度为50 ℃时煤样抗压强度随围压增加而增加，4 MPa围压作用下煤样峰值偏应力达3.6 MPa，煤样轴向、环向应变均达到2%以上，表现出较高的延展性；温度为100 ℃时煤样抵抗变形能力下降，随围压增加，其峰值偏应力增加至4.9 MPa，煤样应变增长的速率加快；围压4 MPa、温度100 ℃时，煤样峰值渗透率达到3.5×10-11 m2；煤样加载过程中原始和新生裂隙扩展，孔隙连通性增强形成复杂的裂隙网络，热力效应使煤样渗流裂隙体积增加，渗透率增加。Abstract: The increase of coal mining depth leads to the increase of ground temperature and stress, which affects the development of fractures and seepage characteristics. In order to study the variation characteristics of deformation and permeability of coal under thermo-mechanical coupling, the MTS815 test system was used to test the permeability of six groups of coal samples during the whole stress-strain process at 50 ℃ and 100 ℃. The results indicated that: when the temperature set to 50 ℃, the compressive strength of coal samples increased with the increase of confining pressure. The peak deviator stress of the coal sample reached to 3.6 MPa under the confining pressure of 4 MPa, and the axial and circumferential strains both reached more than 2%, showing high performance of malleability. The deformation resistance of coal samples decreased when the temperature set to 100 ℃; with the increase of confining pressure, the peak deviant stress increased to 4.9 MPa, and the rate of strain growth accelerated. When the test condition set to 4 MPa and 100 ℃, the peak permeability of coal sample reached to 3.5×10-11 m2. The original and new fractures expanded, and the pore connectivity was enhanced to form a complex fracture network during the loading process. Then, the volume of seepage fractures and permeability of coal samples was increased by thermal effect.
-
-
[1] WANG C, WANG H B, XIE M Z, et al. Study on the dynamic characteristics of rock surrounding a wellbore in energy storage areas during deep geothermal energy mining[J]. PLOS ONE, 2020, 15（8）: e0237823. [2] WANG S G, ELSWORTH D, LIU J S. Permeability evolution during progressive deformation of intact coal and implications for instability in underground coal seams[J]. International Journal of Rock Mechanics and Mining Sciences, 2013, 58: 34－45. [3] LIU X, LIN H X, ZHANG F. Study and application for fracture mechanism of soft coal-rock bonding layer[J]. Electronic Journal of Geotechnical Engineering, 2014, 19（Z5）: 17269－17279. [4] 苏承东，陈晓祥，袁瑞甫．单轴压缩分级松弛作用下煤样变形与强度特征分析[J]．岩石力学与工程学报，2014，33（6）：1135－1141. SU Chengdong, CHEN Xiaoxiang, YUAN Ruifu. Analysis of deformation and strength characteristics of coal samples under uniaxial compression of stepped relaxation[J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33（6）: 1135－1141.
[5] CHU Y P, SUN H T, ZHANG D M. Experimental study on evolution in the characteristics of permeability, deformation, and energy of coal containing gas under triaxial cyclic loading-unloading[J]. Energy Science and Engineering, 2019, 7（5）: 2112－2123. [6] 尚宏波，靳德武，张天军，等．三轴应力作用下破碎煤体渗透特性演化规律[J]．煤炭学报，2019，44（4）：1066－1075. SHANG Hongbo, JIN Dewu, ZHANG Tianjun, et al. Permeability evolution of broken coal under triaxial stress[J]. Journal of China Coal Society, 2019, 44（4）: 1066.
[7] ZHAO J L, TANG D Z, LIN W J, et al. In-situ stress distribution and its influence on the coal reservoir permeability in the Hancheng area, eastern margin of the Ordos Basin, China[J]. Journal of Natural Gas Science and Engineering, 2019, 61: 119－132. [8] 孟召平，章朋，田永东，等．围压下煤储层应力－应变、渗透性与声发射试验分析[J]．煤炭学报，2020，45（7）：2544－2551. MENG Zhaoping, ZHANG Peng, TIAN Yongdong, et al. Experimental analysis of stress-strain, permeability and acoustic emission of coal reservoir under different confining pressures[J]. Journal of China Coal Society, 2020, 45（7）: 2544－2551.
[9] LU J, YIN G Z, DENG B Z, et al. Permeability characteristics of layered composite coal-rock under true triaxial stress conditions[J]. Journal of Natural Gas Science and Engineering, 2019, 66: 60－76. [10] ZHU W C, WEI C H, LIU J, et al. A model of coal gas interaction under variable temperatures[J]. International Journal of Coal Geology, 2011, 86（23）: 213－221. [11] 梁冰，高红梅，兰永伟．岩石渗透率与温度关系的理论分析和试验研究[J]．岩石力学与工程学报，2005， 24（12）：2009－2012. LIANG Bing, GAO Hongmei, LAN Yongwei. Theoretical analysis and experimental study on relation between rock permeability and temperature[J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24（12）: 2009－2012.
[12] TENG T, GAO F J, JIANG C B. A thermally sensitive permeability model for coal gas interactions including thermal fracturing and volatilization[J]. Journal of Natural Gas Science and Engineering, 2016, 32: 319－333. [13] YIN G Z, JIANG C B, XU J. Combined effect of stress, pore pressure and temperature on methane permeability in anthracite coal: an experimental study[J]. Transport in Porous Media, 2013, 100（1）: 1－16. [14] 尹光志，李文璞，李铭辉，等．加卸载条件下原煤渗透率与有效应力的规律[J]．煤炭学报，2014，39（8）：1497－1503. YIN Guangzhi, LI Wenpu, LI Minghui, et al. Permeability properties and effective stress of raw coal under loading-unloading conditions[J]. Journal of China Coal Society, 2014, 39（8）: 1497－1503.
[15] FENG Z J, WAN Z J, ZHAO Y S, et al. Experiment study of permeability of anthracite and gas coal masses under high temperature and triaxial stress[J]. Rock Mechanics and Rock Engineering, 2010, 29（4）: 689. [16] LI B B, YANG K, XU P, et al. An experimental study on permeability characteristics of coal with slippage and temperature effects[J]. Journal of Petroleum Science and Engineering, 2019, 17（5）: 294－302. [17] 胡雄，梁为，朱学光，等．温度与应力对原煤、型煤渗透特性影响的试验研究[J]．岩石力学与工程学报，2012，31（6）：1222－1229. HU Xiong, LIANG Wei, ZHU Xueguang, et al. Experimental study of effect of temperature and stress on permeability characteristics of raw coal and shaped coal[J]. Chinese Journal of Rock Mechanics and Engineering, 2012, 31（6）: 1222－1229.
[18] 蒋明镜，肖俞，孙渝刚，等．水泥胶结颗粒的微观力学模型试验[J]．岩土力学，2012，33（5）：1293－1299. JIANG Mingjing, XIAO Yu, SUN Yugang, et al. Experimental investigation on micromechanical model of cement-bonded particles[J]. Rock and Soil Mechanics, 2012, 33（5）: 1293－1299.
[19] 王广荣，薛东杰，郜海莲，等．煤岩全应力－应变过程中渗透特性的研究[J]．煤炭学报，2012，37（1）：107－112. WANG Guangrong, XUE Dongjie, HAO Hailian, et al. Study on permeability characteristics of coal rock in complete stress-strain process[J]. Journal of China Coal Society, 2012, 37（1）: 107－112.
[20] 卢义玉,贾云中,汤积仁,等.非均匀孔隙压力场导向水压裂纹扩展机制[J].东北大学学报（自然科学版），2016，22（7）：1028-1033. LU Yiyun, JIA Yunzhong, TANG Jiren, et al. Non-uniform pore pressure field; hydrofracture; stress intensity factor; fracture propagation control[J]. Journal of Northeastern University（Natural Science）, 2016, 22（7）: 1028-1033.
[21] 陈春谏．热－力耦合作用下煤岩渗流及声发射特性试验研究[D]．太原：太原理工大学，2019. [22] 李波波，王斌，杨康，等．应力与温度综合作用的煤岩渗透机理[J]．中国矿业大学学报，2020，49（5）：844. LI Bobo, WANG Bin, YANG Kang, et al. Coal seepage mechanism effected by stress and temperature[J]. Journal of China University of Mining & Technology, 2020, 49（5）: 844－855.
计量
- 文章访问数: 38
- HTML全文浏览量: 5
- PDF下载量: 27
下载:
