Research and application of directional drilling sub area extraction in thick coal seam goaf

doi:10.16265/j.cnki.issn1003-3033.2023.01.0416

Abstract

Abstract:

In order to improve the gas drainage efficiency of directional drilling in thick coal seam goaf, the experiment was carried out in a coal face of a high gas mine in Shanxi province. The method of combining theoretical analysis with FLUENT numerical simulation was used to study the regional evolution characteristics of mining induced fractures. According to the experimental results, the zoning criteria of overburden fracture field were proposed to determine the layout area of directional boreholes and the layout range of key gas drainage boreholes. The gas extraction test of goaf by directional long boreholes was carried out on the site of goaf. The test results show that in the fracture concentrated area, the longitudinal development of fractures is obvious, the gas accumulation is significant, and the stability of gas drainage boreholes is high. Therefore, this area is the best area for directional drilling. The key area for the arrangement of gas drainage boreholes is the area with a horizontal distance of 3-13 m from the center line of the air return roadway and a vertical distance of 10-18 m from the roof of the coal seam. In the experiment of gas extraction in layers by directional boreholes, the average volume fraction of single hole gas extraction increases by 22.355%, and the average pure gas extraction volume of single hole increases by 1.295 m³/min. This conclusion verifies the practicability and rationality of the gas drainage method of directional drilling in goaf of thick coal seam.

Key words: thick seam, goaf, directional drilling, zoning criteria, gas extraction, mining-induced overburden fractures, numerical simulation

ZHAO Pengxiang, CHANG Zechen, LI Shugang, ZHUO Risheng, LIN Haifei, JIN Shikui. Research and application of directional drilling sub area extraction in thick coal seam goaf[J]. China Safety Science Journal, 2023, 33(1): 70-79.

Figures/Tables 13

Tab.1

Results of height for “Three Zones” in working face

方法	$H C$ /m	$H F$ /m	$H B$ /m
理论分析	22.8	72.2	—
物理模拟	15.8	61.9	82.1
现场观测	25	60	80
综合结果	21.2	64.7	81.05

Tab.1

Fig.1

Fig.2

Tab.2

Fig.3

Fig.4

Tab.3

Fig.5

Tab.4

Fig.6

Fig.7

Fig.8

Fig.9

References 29

[1]	张庆贺, 袁亮, 杨科, 等. 深井煤岩动力灾害的连续卸压开采防治机理[J]. 采矿与安全工程学报, 2019, 36(1): 84-90, 106.
	ZHANG Qinghe, YUAN Liang, YANG Ke, et al. Mechanism analysis on continuous stress-relief mining for preventing coal and rock dynamic disasters in deep coal mines[J]. Journal of Mining and Safety Engineering, 2019, 36(1): 84-90, 106.
[2]	高魁, 乔国栋, 刘健, 等. 构造复杂矿区煤与瓦斯突出瓦斯地质分析[J]. 中国安全科学学报, 2019, 29(1):119-124. doi: 10.16265/j.cnki.issn1003-3033.2019.01.020
	GAO Kui, QIAO Guodong, LIU Jian, et al. Gas-geology action analysis of coal-gas outburst in complicated geological structure coal mine[J]. China Safety Science Journal, 2019, 29(1): 119-124. doi: 10.16265/j.cnki.issn1003-3033.2019.01.020
[3]	汪腾蛟, 聂朝刚, 杨小彬, 等. 考虑温度变化的采空区瓦斯抽采数值模拟[J]. 煤炭科学技术, 2021, 49(7):85-94.
	WANG Tengjiao, NIE Chaogang, YANG Xiaobin, et al. Numerical simulation of gas drainage in gob considering temperature change[J]. Coal Science and Technology, 2021, 49(7): 85-94.
[4]	杨正凯, 程志恒, 刘彦青, 等. 突出煤层群多次采动对底板穿层钻孔瓦斯抽采的影响[J]. 中国安全科学学报, 2020, 30(5):66-73. doi: 10.16265/j.cnki.issn1003-3033.2020.05.011
	YANG Zhengkai, CHENG Zhiheng, LIU Yanqing, et al. Influence of multiple mining of outburst coal seam group on gas extraction of cross-layer borehole[J]. China Safety Science Journal, 2020, 30(5): 66-73. doi: 10.16265/j.cnki.issn1003-3033.2020.05.011
[5]	张智渊, 朱传杰, 刘思远, 等. 复合储层层间窜流对瓦斯抽采的影响机制研究[J]. 煤矿安全, 2022, 53(2): 1-8.
	ZHANG Zhiyuan, ZHU Chuanjie, LIU Siyuan, et al. Influence of interlayer channeling of composite reservoir on gas drainage[J]. Safety in Coal Mines, 2022, 53(2): 1-8.
[6]	年军, 高巍, 李润芝, 等. 以孔代巷瓦斯抽采布孔间距模拟及试验研究[J]. 中国安全科学学报, 2019, 29(5): 117-123. doi: 10.16265/j.cnki.issn1003-3033.2019.05.020
	NIAN Jun, GAO Wei, LI Runzhi, et al. Simulation and experimental study on space between boreholes for gas drainage instead of roadway[J]. China Safety Science Journal, 2019, 29(5): 117-123. doi: 10.16265/j.cnki.issn1003-3033.2019.05.020
[7]	KARMIS M, TRIPLETT T, HAYCOCKS C, et al. Mining subsidence and its prediction in appalachian coalfield[C]. Rock Mechanics: Theory, Experiment, Practice. Proceedings, Process 24th US Symp. Rock Mechanics, 1983:665-675.
[8]	BAI Mao, ELSWORTH D. Some aspects of mining under aquifers in China[J]. Mining Science and Technology, 1990, 10(1): 81-91. doi: 10.1016/0167-9031(90)90878-V
[9]	PAL-CHIK V. Influence of physical characteristics of weak rock mass on height of caved zone over abandoned subsurface coal mines[J]. Environmental Geology, 2002, 42(1): 92-101. doi: 10.1007/s00254-002-0542-y
[10]	刘天泉. 矿山岩体采动影响与控制工程学及其应用[J]. 煤炭学报, 1995, 20(1):1-5.
	LIU Tianquan. Influence of mining activities on mine rockmass and control engineering[J]. Journal of China Coal Society, 1995, 20(1): 1-5.
[11]	ABBAS Majdi. Prediction of the height of destressed zone above the mined panel roof in longwall coal mining[J]. International Journal of Coal Geology, 2012, 98: 62-72. doi: 10.1016/j.coal.2012.04.005
[12]	李树刚, 林海飞, 赵鹏翔, 等. 采动裂隙椭抛带动态演化及煤与甲烷共采[J]. 煤炭学报, 2014, 39(8): 1455-1462.
	LI Shugang, LIN Haifei, ZHAO Pengxiang, et al. Dynamic evolution of mining fissure elliptic paraboloid zone extraction coal and gas[J]. Journal of China Coal Society, 2014, 39(8): 1455-1462.
[13]	杨科, 谢广祥. 综放开采采动裂隙分布及其演化特征分析[J]. 矿业安全与环保, 2009, 36(4):1-3, 91.
	YANG Ke, XIE Guangxiang. Distribution of mining fissures induced by fully mechanized caving mining and analysis on their evolvement characteristics[J]. Mining Safety and Environmental Protection, 2009, 36(4): 1-3, 91.
[14]	LIN Haifei, LI Shugang, CHENG Lianhua. Studies on distribution features and internal methane concentration distribution laws of mining-induced fracture zone[C]. Progress in Safety Science and Technology, 2006: 1680-1685.
[15]	常聚才, 谢广祥, 张学会. 特厚煤层大采高综放工作面煤壁片帮机制分析[J]. 岩土力学, 2015, 36(6): 803-808.
	CHANG Jucai, XIE Guangxiang, ZHANG Xuehui. Analysis of rib spalling mechanism of fully-mechanized top-coal caving face with great mining height in extra-thick coal seam[J]. Rock and Soil Mechanics, 2015, 36 (6): 803-808.
[16]	郭寿松. 大采高工作面煤壁片帮观测及其控制措施[J]. 矿业安全与环保, 2017, 44(3): 62-64.
	GUO Shousong. Observation of coal wall spalling in coal face with large mining height and its control measures[J]. Mining Safety and Environmental Protection, 2017, 44(3): 62-64.
[17]	贾毅超, 刘萍, 韩森, 等. 近距离煤层群采空区高位定向钻孔布置优化研究[J]. 矿业研究与开发, 2022, 42(2): 18-23.
	JIA Yichao, LIU Ping, HAN Sen, et al. Optimization study on high directional borehole layout in goaf of close distance coal seam group[J]. Mining Research and Development, 2022, 42(2): 18-23.
[18]	李卫龙, 汪青, 刘欣, 等. 煤矿瓦斯抽采智能系统设计[J]. 煤矿机械, 2021, 42(8): 14-17.
	LI Weilong, WANG Qing, LIU Xin, et al. Design of intelligent system for gas extraction in coal mine[J]. Coal Mine Machinery, 2021, 42(8): 14-17.
[19]	丁洋, 朱冰, 李树刚, 等. 高突矿井采空区卸压瓦斯精准辨识及高效抽采[J]. 煤炭学报, 2021, 46(11):3565-3577.
	DING Yang, ZHU Bing, LI Shugang, et al. Accurate and efficient drainage of relieved methane in goaf of high outburst mine[J]. Journal of China Coal Society, 2021, 46(11): 3565-3577.
[20]	张志敏. 不同通风方式下顶板高位定向钻孔瓦斯抽放效果研究[J]. 煤炭与化工, 2021, 44(11): 107-110, 113.
	ZHANG Zhimin. Gas drainage effect of high-level directional drilling in roof under different ventilation modes[J]. Coal and Chemical Industry, 2021, 44(11): 107-110, 113.
[21]	张朝举, 方俊, 杨亚黎, 等. 祁东煤矿近距离煤层群瓦斯治理顶板拦截定向钻孔试验[J]. 工矿自动化, 2021, 47(11): 112-118.
	ZHANG Chaoju, FANG Jun, YANG Yali, et al. Test of interception directional drilling for close distance coal seam group gas control in Qidong coal mine[J]. Journal of Mine Automation, 2021, 47(11): 112-118.
[22]	任建平, 王宁. 高位定向长钻孔替代普通倾向孔工程实践[J]. 煤炭技术, 2021, 40(9): 121-125.
	REN Jianping, WANG Ning. Engineering practice of high-level directional long borehole replacing ordinary high-level tendency borehole[J]. Coal Technology, 2021, 40(9): 121-125.
[23]	林海飞, 杨二豪, 夏保庆, 等. 高瓦斯综采工作面定向钻孔代替尾巷抽采瓦斯技术[J]. 煤炭科学技术, 2020, 48(1):136-143.
	LIN Haifei, YANG Erhao, XIA Baoqing, et al. Directional drilling replacing tailgate gas drainage technology in gassy fully-mechanized coal mining face[J]. Coal Science and Technology, 2020, 48(1): 136-143.
[24]	李彦明. 基于高位定向长钻孔的上隅角瓦斯治理研究[J]. 煤炭科学技术, 2018, 46(1):215-218.
	LI Yanming. Upper corner gas control based on high level directional long borehole[J]. Coal Science and Technology, 2018, 46(1): 215-218.
[25]	刘超杰, 高运增, 赵高博, 等. 厚松散层软弱覆岩工作面“三带”发育特征与高度研究[J]. 矿业安全与环保, 2022, 49(1): 53-58.
	LIU Chaojie, GAO Yunzeng, ZHAO Gaobo, et al. Study on the development characteristics and height of "three zones" of the working face covered with thick alluvium and weak overburden[J]. Mining Safety and Environmental Protection, 2022, 49(1): 53-58.
[26]	侯国培, 郭昆明, 岳茂庄, 等. 高位定向长钻孔瓦斯抽采技术应用[J]. 煤炭工程, 2019, 51(1): 64-67.
	HOU Guopei, GUO Kunming, YUE Maozhuang, et al. Application of gas drainage technology in high-level directional long drilling hole[J]. Coal Engineering, 2019, 51(1): 64-67.
[27]	黄健丰, 吴璋, 王玉涛, 等. 水库下伏采空区覆岩裂隙探查与综合防治技术[J]. 煤矿安全, 2020, 51(2): 90-96.
	HUANG Jianfeng, WU Zhang, WANG Yutao, et al. Exploration and comprehensive treatment technology of overburden fracture in underlying goaf of reservoir[J]. Safety in Coal Mines, 2020, 51(2): 90-96.
[28]	郭明杰, 郭文兵, 袁瑞甫, 等. 基于采动裂隙区域分布特征的定向钻孔空间位置研究[J]. 采矿与安全工程学报, 2022, 39(4): 817-826.
	GUO Mingjie, GUO Wenbing, YUAN Ruifu, et al. Spatial location determination of directional boreholes based on regional distribution characteristics of mining-induced overburden fractures[J]. Journal of Mining and Safety Engineering, 2022, 39(4): 817-826.
[29]	关键, 郭正. 绕翼型低雷诺数流动的数值仿真[J]. 科学技术与工程, 2013, 13(24):7275-7281.
	GUAN Jian, GUO Zheng. Numerical simulations of low-reynolds-number flows over the E387 airfoil[J]. Science Technology and Engineering, 2013, 13(24): 7275- 7281.

序号	模拟条件	模拟目的
1	U型通风,风量2 850 m³/min,定向钻孔垂距15 m,平距3、13、23 m,核心抽采区域位于破断裂隙密集区内	确定定向钻孔合理平距
2	U型通风,风量2 850 m³/min,定向钻孔平距由第一步确定,垂距10、18、 26 m, 核心抽采区域位于破断裂隙密集区内	确定定向钻孔合理垂距

钻孔参数/m		抽采量/ (m³·min^-1)	瓦斯抽采体积分数/%	抽采纯量/ (m³·min^-1)	上隅角瓦斯体积分数/%
与回风巷中心线水平距离	3	10	25~38	2.50~3.80	0.65~0.90
	13	10	19~23	1.90~2.30	0.79~0.92
	23	10	15~18	1.50~1.80	0.87~1.13
与煤层顶板垂直距离	10	10	10~15	1.00~1.50	0.77~0.85
	18	10	19~23	1.90~2.30	0.81~0.97
	26	10	28~35	2.80~3.50	0.93~1.09

钻场设计参数			钻孔设计参数
钻场尺寸(宽×深× 高)/m×m×m	钻场间距/m	钻孔搭接/m	钻孔直径/mm	钻孔深度/m	钻孔高度/m	内错距离/m
8×6×3	400	50	94	450	距煤层上方10~18	距回风巷3~13