不同冲击方向下高压气体致裂岩石特征试验

doi:10.16265/j.cnki.issn1003-3033.2024.02.0578

摘要/Abstract

摘要：

为探索含瓦斯煤层增透性,提高抽采率,利用自主研制的真三轴高压气体冲击致裂岩石试验系统,开展不同冲击方向下高压气体致裂试验,试验变量为气体冲击方向与最大水平主应力的夹角,在三向应力的作用下开展高压气体冲击试验,得到冲击方向与最大水平主应力呈现0、30、45、60和90°夹角时岩石破裂形态及声发射响应。结果表明:高压气体冲击致裂岩石过程呈现5个显著阶段,即冲击起裂阶段、气压上升阶段、裂缝扩展阶段、气压稳定阶段和压力衰减阶段;高压气体冲击产生垂直裂缝和水平裂缝,射流角度增加后,垂直裂缝出现偏转,且偏转角度逐渐变大,裂缝偏转点也逐渐远离钻孔,水平断裂面呈现中间低四周高的形态;气体峰值压力随着射流方向与最大主应力的角度增加而增加,从0~90°峰值压力呈线性增长;分析声发射信号发现,岩石冲击破坏以张拉破坏为主、剪切破坏为辅,但随着射流角度增加,逐渐转变为剪切破坏为主的拉-剪复合破坏。

关键词: 高压气体, 致裂岩石, 冲击方向, 声发射, 裂缝扩展

Abstract:

To explore the enhanced permeability of gas-containing coal seams and improve extraction efficiency, high-pressure gas fracturing tests under different impact directions were performed by a self-developed true triaxial high-pressure gas impact rock fracturing test system. The test variable was the angle between gas impact direction and maximum horizontal principal stress. High-pressure gas impact tests were performed under the actions of three triaxial stress, and rock fracture morphology and acoustic emission response were obtained at angles between the impact direction and the maximum horizontal principal stress of 0, 30, 45, 60, and 90°. The results indicated that the rock fracturing process caused by high-pressure gas presented five significant stages including the impact crack initiation stage, air pressure rising stage, crack propagation stage, air pressure stabilization stage, and pressure attenuation stage; High-pressure gas impact caused vertical and horizontal cracks. Vertical cracks were deflected, and the deflection angle increased with the increment of the jet angle. Moreover, the crack deflection points gradually moved away from the drilling hole, and the horizontal fracture surface took on a shape of low in the middle and high in surrounding areas. The maximum gas pressure increased with the angle between the jet direction and the maximum principal stress, and the peak pressure represented a linear increment from 0 to 90°; The acoustic emission signals analysis indicated that rock impact failure was primarily caused by tensile failure and supplemented by shear failure. However, as the jet angle increased, it gradually became a tensile-shear composite failure dominated by shear failure.

Key words: high-pressure gas, fracturing rock, impact direction, acoustic emission, crack propagation

中图分类号:

X936

张纪辉, 马衍坤, 谭辉, 赵敖寒. 不同冲击方向下高压气体致裂岩石特征试验[J]. 中国安全科学学报, 2024, 34(2): 200-207.

ZHANG Jihui, MA Yankun, TAN Hui, ZHAO Aohan. Experimental study on characteristics of rock fracturing by high-pressure gas under different impact directions[J]. China Safety Science Journal, 2024, 34(2): 200-207.

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参考文献 18

[1]	袁亮, 王恩元, 马衍坤, 等. 我国煤岩动力灾害研究进展及面临的科技难题[J]. 煤炭学报, 2023, 48(5):1825-1845.
	YUAN Liang, WANG Enyuan, MA Yankun, et al. Research progress and technological challenges faced by coal and rock dynamic disasters in China[J]. Journal of China Coal Society, 2023, 48 (5): 1825-1845.
[2]	范超军, 李胜, 兰天伟, 等. 不同因素对水力压裂促抽煤层瓦斯的影响[J]. 中国安全科学学报, 2017, 27(12):97-102. doi: 10.16265/j.cnki.issn1003-3033.2017.12.017
	FAN Chaojun, LI Sheng, LAN Tianwei, et al. Influences of different factors on enhancing methane drainage by hydraulic fracturing[J]. China Safety Science Journal, 2017, 27 (12): 97-102. doi: 10.16265/j.cnki.issn1003-3033.2017.12.017
[3]	XIE Heping, GAO Feng, JU Yang, et al. Novel idea of the theory and application of 3D volume fracturing for stimulation of shale gas reservoirs[J]. Science Bulletin, 2016, 61:36-46.
[4]	LI Xiang, FENG Zijun, HAN Gang, et al. Breakdown pressure and fracture surface morphology of hydraulic fracturing in shale with H₂O, CO₂ and N₂[J]. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2016, 2(2):63-76. doi: 10.1007/s40948-016-0022-6
[5]	张东明, 白鑫, 尹光志, 等. 低渗煤层液态CO₂相变定向射孔致裂增透技术及应用[J]. 煤炭学报, 2018, 43(7):1938-1950.
	ZHANG Dongming, BAI Xin, YIN Guangzhi, et al. Research and application on technology of increased permeability by liquid CO₂ phase change directional jet fracturing in low-permeability coal seam[J]. Journal of China Coal Society, 2018, 43(7):1938-1950.
[6]	李守国. 高压空气爆破煤层增透关键技术与装备研发[J]. 煤炭科学技术, 2015, 43(2):92-95.
	LI Shouguo Research and development of key technology and equipment for coal seam antireflection by high pressure air blasting[J]. Coal Science and Technology, 2015, 43 (2): 92-95.
[7]	曾范永. 煤体高压气体爆破致裂规律的实验研究[J]. 煤矿安全, 2019, 50(1):13-16.
	ZENG Fanyong Experimental study on cracking laws of high pressure gas explosion in coal[J]. Safety in Coal Mires, 2019, 50 (1): 13-16.
[8]	CAO Yunxing, ZHANG Junsheng, ZHAI Hong, et al. CO₂ gas fracturing: a novel reservoir stimulation technology in low permeability gassy coal seams[J]. Fuel, 2017, 203:197-207. doi: 10.1016/j.fuel.2017.04.053
[9]	YANG Xuelin, WEN Guangcai, SUN Haitao, et al. Environmentally friendly techniques for high gas content thick coal seam stimulation-multi-discharge CO₂ fracturing system[J]. Journal of Natural Gas Science and Engineering, 2019, 61:71-82. doi: 10.1016/j.jngse.2018.11.006
[10]	王登科, 张平, 浦海, 等. 温度冲击下媒体裂隙结构演化的显微CT实验研究[J]. 岩石力学与工程学报, 2018, 37(10):2243-2252.
	WANG Dengke, ZHANG Ping, PU Hai, et al. Experimental research on cracking process of coal under temperature variation with industrial micro-CT[J] Journal of Rock Mechanics and Engineering, 2018, 37 (10): 2243-2252.
[11]	赵旭. 高压氮气冲击致裂煤岩体裂隙发育规律研究[D]. 徐州: 中国矿业大学, 2017.
	ZHAO Xu. Study on fracture development law of coal and rock mass caused by high pressure nitrogen impact[D]. Xuzhou: China University of Mining and Technology, 2017.
[12]	柴金飞. 基于矩张量理论的脆性岩石破裂机理研究[D]. 北京: 北京科技大学, 2017.
	CHAI Jinfei. Research on fracture mechanism of brittle rock based on moment tensor theory[D]. Beijing: University of Science and Technology Beijing, 2017.
[13]	何云松. 基于矩张量的岩石破裂微观机制声发射研究[D]. 成都: 成都理工大学, 2017.
	HE Yunsong. Acoustic emission study on micro mechanism of rock fracture based on moment tensor[D]. Chengdu: Chengdu University of Technology, 2017.
[14]	AGGELIS D G. Classification of cracking mode in concrete by acousticemission parameters[J]. Mechanics Research Communications, 2011, 38(3):153-157. doi: 10.1016/j.mechrescom.2011.03.007
[15]	FENG Xiating, YOUNG R P, REYES-MONTES J M, et al. ISRM suggested method for insitu acoustic emission monitoring of the fracturing process in rockmasses[J]. Rock Mechanics and Rock Engineering, 2019, 52: 1395-1414. doi: 10.1007/s00603-019-01774-z
[16]	KOURKOULIS S K, PASIOU E D, DAKANA LI, et al. Notched marble plates under direct tension: mechanical response and fracture[J]. Construction & Building Materials, 2018, 167 (10): 426-439.
[17]	甘一雄. 地下工程岩体破裂声发射参数表征研究与定位方法优化[D]. 北京: 北京科技大学, 2020.
	GAN Yixiong. Research on the characterization of acoustic emission parameters for underground engineering rock mass fractures and optimization of localization methods[D]. Beijing: Beijing University of Science and Technology, 2020.
[18]	唐巨鹏, 路江伟, 许鹏, 等. 煤系页岩水力压裂声发射时频特征试验研究[J]. 中国安全科学学报, 2017, 27(10):87-92. doi: 10.16265/j.cnki.issn1003-3033.2017.10.015
	TANG Jupeng, LU Jiangwei, XU Peng, et al. Experimental study on time-frequency characteristics of hydraulic fracturing acoustic emission in coal shale[J]. China Safety Science Journal, 2017, 27 (10): 87-92. doi: 10.16265/j.cnki.issn1003-3033.2017.10.015

试样	射流方向/ (°)	三轴应力/ MPa	气体压力/ MPa
L1	0	σ_h=4.8 σ_H=6.4 σ_V=8	16
L2	30		16
L3	45		16
L4	60		16
L5	90		16

时段	0°耗时	30°耗时	45°耗时	60°耗时	90°耗时
B—C	28	25	25	30.5	34
C—D	23.5	24.5	25	45	43.5
D—E	154.5	170	167	140.5	119
E—F	420	398.5	392.5	396.5	420
F—G	1 293	1 882.5	1 726	1 763	1 282

试样	射流方向	最大角度	最小角度
L1	0	23.9	20.3
L2	30	28.2	20.4
L3	45	33.9	16.1
L4	60	30.5	13.1
L5	90	34.5	0

试样	射孔角度/ (°)	偏转角度/ (°)	偏转处距钻孔距离/mm
L1	0	0	0
L2	30	30	21
L3	45	45	31
L4	60	15	21
L5	90	45	66