Quantitative study of 3D numerical simulation on optimizing borehole layout spacing of gas drainage

Authors

CHEN Yuexia, School of Emergency Technology and Management, North China Institute of Science and Technology, Langfang 065201, China
CHU Tingxiang, School of Safety Supervision, North China Institute of Science and Technology, Langfang 065201, China
CHEN Peng, School of Safety Supervision, North China Institute of Science and Technology, Langfang 065201, China
TANG Yang, School of Civil Engineering, Chongqing University of Arts and Sciences, Chongqing 402160, China

Abstract

In order to optimize the spacing of boreholes and realize efficient drainage, based on the fluid solid coupling model, a three-dimensional geometric model was established to make it closer to the field reality, the gas drainage processes of a coal mine with different borehole spacing were simulated using COMSOL software. The results show that: the effective drainage area was visualized by the three-dimensional diagram of the isobaric surface with gas pressure of 0.74 MPa, and the influence of borehole spacing on the extraction efficiency was discussed. The results show that: the effective extraction radius is about 1.5 m during gas extraction with single borehole at 120 days; when the borehole spacing d was 5 m during gas extraction with multiple boreholes at 120 days, the isobaric surface with gas pressure of 0.74 MPa was approximately cylindrical around all the boreholes, but it was sunken to the interior(there is a blanking zone); when the borehole spacing were 2.1 m, 3 m, 4 m, 5 m and 6 m respectively, the order of the volumes of the effective drainage area V changed with the growth of time; at 120 days, the order was V_{d=5 m}>V_{d=4 m}>V_{d=3 m}>V_{d=2.1 m}>V_{d=6 m}. According to the three-dimensional diagram of gas pressure isobaric surface and the order of effective drainage area volumes, the optimal borehole spacing is determined to be 4 m. In this paper, a numerical investigation method for borehole spacing based on effective extraction radius, superposition effect, shape of isobaric surface of three-dimension of gas pressure and volume of effective extraction area was presented, providing reference for optimizing layout of borehole spacing in underground coal mines.

Keywords

gas drainage, space of boreholes, effective gas drainage area, numerical simulation

DOI

10.3969/j.issn.1001-1986.2021.03.010

Recommended Citation

CHEN Yuexia, CHU Tingxiang, CHEN Peng, et al. (2021) "Quantitative study of 3D numerical simulation on optimizing borehole layout spacing of gas drainage," Coal Geology & Exploration: Vol. 49: Iss. 3, Article 11.
DOI: 10.3969/j.issn.1001-1986.2021.03.010
Available at: https://cge.researchcommons.org/journal/vol49/iss3/11

Reference

[1] ZHANG Chaolin,WANG Enyuan,XU Jiang,et al. A new method for coal and gas outburst prediction and prevention based on the fragmentation of ejected coal[J]. Fuel,2021,287:119493.

[2] YANG Chunli,LI Xiangchun,REN Yanbin,et al. Statistical analysis and countermeasures of gas explosion accident in coal mines[J]. Procedia Engineering,2014,84:166-171.

[3] SHI Juntai,WANG Shan,WANG Ke,et al. An accurate method for permeability evaluation of undersaturatedcoalbed methane reservoirs using early dewatering data[J]. International Journal of Coal Geology,2019,202:147-160.

[4] 王晶,姚团琪,程斌. 基于煤矿"先抽后建"及资源开发的煤层气地面井位抽采部署及应用[J]. 煤田地质与勘探, 2019,47(4):28-32. WANG Jing,YAO Tuanqi,CHENG Bin. Research and application of CBM surface extraction based on coal mine with "gas drainage first,construction later" and resource development[J]. Coal Geology & Exploration,2019,47(4):28-32.

[5] 方佳伟,韩保山,周加佳,等. 基于工作面全覆盖的地面瓦斯高效抽采模式研究[J]. 煤田地质与勘探,2020,48(3):81-85. FANG Jiawei,HAN Baoshan,ZHOU Jiajia,et al. Surface efficient gas extraction mode based on full coverage of working face[J]. Coal Geology & Exploration,2020,48(3):81-85.

[6] 刘永茜,张书林,舒龙勇. 吸附-解吸状态下煤层气运移机制[J]. 煤田地质与勘探,2019,47(4):12-18. LIU Yongqian,ZHANG Shulin,SHU Longyong. Coalbed methane migration mechanism under adsorption-desorption condition in coal[J]. Coal Geology & Exploration,2019,47(4):12-18.

[7] 李宏,马金魁. 顶板大直径定向长钻孔参数优化与优势分析[J]. 煤炭科学技术. http://kns.cnki.net/kcms/detail/11.2402.TD.20200212.2018.008.html. LI Hong,MA Jinkui. Parameter optimization and advantage analysis of large diameter directional long hole in roof[J]. Coal Science and Technology. http://kns.cnki.net/kcms/detail/11.2402.TD.20200212.2018.008.html

[8] 齐黎明,祁明,陈学习. 抽采钻孔周围煤层瓦斯压力分布理论分析及应用[J]. 中国安全科学学报,2018,28(7):102-108. QI Liming,QI Ming,CHEN Xuexi. Theoretical analysis of coal seam gas pressure distribution around drainage hole and its application[J]. China Safety Science Journal,2018,28(7):102-108.

[9] LIU Zhengdong,CHENG Yuanping,JIANG Jingyu,et al. Interactions between coal seam gas drainage boreholes and the impact of such on borehole patterns[J]. Journal of Natural Gas Science and Engineering,2017,38:597-607.

[10] 李波,孙东辉,张路路. 煤矿顺层钻孔瓦斯抽采合理布孔间距研究[J]. 煤炭科学技术,2016,44(8):121-126. LI Bo,SUN Donghui,ZHANG Lulu. Study on rational space between gas drainage boreholes passing through seam in coal mine[J]. Coal Science and Technology,2016,44(8):121-126.

[11] 王兆丰,李炎涛,夏会辉,等. 基于COMOSOL的顺层钻孔有效抽采半径的数值模拟[J]. 煤矿安全,2012,43(10):4-6. WANG Zhaofeng,LI Yantao,XIA Huihui,et al. Numerical simulation on effective drainage radius of drill hole along coal seam based on COMSOL[J]. Safety in Coal Mines,2012,43(10):4-6.

[12] 马耕,苏现波,魏庆喜. 基于瓦斯流态的抽放半径确定方法[J]. 煤炭学报,2009,34(4):501-504. MA Geng,SU Xianbo,WEI Qingxi. The determination method of coal gas drainage radius based on methane flow state[J]. Journal of China Coal Society,2009,34(4):501-504.

[13] 刘三钧,马耕,卢杰,等. 基于瓦斯含量的相对压力测定有效半径技术[J]. 煤炭学报,2011,36(10):1715-1719. LIU Sanjun,MA Geng,LU Jie,et al. Relative pressure determination technology for effective radius found on gas content[J]. Journal of China Coal Society,2011,36(10):1715-1719.

[14] 郝富昌,刘明举,孙丽娟. 基于多物理场耦合的瓦斯抽放半径确定方法[J]. 煤炭学报,2013,38(增刊1):106-111. HAO Fuchang,LIU Mingju,SUN Lijuan. Determination method of gas drainage radius based on multi-physics coupling[J]. Journal of China Coal Society,2013,38(Sup.1):106-111.

[15] 郝富昌,刘明举,孙丽娟. 瓦斯抽采半径确定方法的比较及存在问题研究[J]. 煤炭科学技术,2012,40(12):55-58. HAO Fuchang,LIU Mingju,SUN Lijuan. Study on comparison of methods to determine gas drainage radius and existed problems[J]. Coal Science and Technology,2012,40(12):55-58.

[16] 梁冰,袁欣鹏,孙维吉,等. 分组测压确定瓦斯有效抽采半径试验研究[J]. 采矿与安全工程学报,2013,30(1):132-135. LIANG Bing,YUAN Xinpeng,SUN Weiji,et al. Grouped pressure test to determine effective gas drainage radius[J]. Journal of Mining & Safety Engineering,2013,30(1):132-135.

[17] 李润芝,梁冰,孙维吉,等. 顺层钻孔瓦斯抽采半径及布孔间距试验研究[J]. 中国安全科学学报,2016,26(10):133-138. LI Runzhi,LIANG Bing,SUN Weiji,et al. Experimental study on both gas drainage radius and bedding borehole space[J]. China Safety Science Journal,2016,26(10):133-138.

[18] 林柏泉,宋浩然,杨威,等. 基于煤体各向异性的煤层瓦斯有效抽采区域研究[J]. 煤炭科学技术,2019,47(6):139-145. LIN Baiquan,SONG Haoran,YANG Wei,et al. Study on effective gas drainage area based on anisotropic coal seam[J]. Coal Science and Technology,2019,47(6):139-145.

[19] ZHANG Chaolin,XU Jiang,PENG Shoujian,et al. Experimental study of drainage radius considering borehole interaction based on 3D monitoring of gas pressure in coal[J]. Fuel,2019,239:955-963.

[20] 许江,宋肖徵,彭守建,等. 顺层钻孔布置间距对煤层瓦斯抽采效果影响的物理模拟试验研究[J]. 岩土力学,2019,40(12):4581-4589. XU Jiang,SONG Xiaozheng,PENG Shoujian,et al. Physical simulation experiment on influence of borehole spacing along the seam on effect of gas drainage[J]. Rock and Soil Mechanics,2019,40(12):4581-4589.

[21] XIA Tongqiang,GAO Feng,KANG Jianhong,et al. A fully coupling coal-gas model associated with inertia and slip effects for CBM migration[J]. Environmental Earth Sciences,2016, 75(7):582.

[22] ZHANG Hongbin,LIU Jishan,ELSWORTH D. How sorption-induced matrix deformation affects gas flow in coal seams:A new FE model[J]. International Journal of Rock Mechanics and Mining Sciences,2008,45(8):1226-1236.

[23] PALMER I,MANSOORI J. How permeability depends on stress and pore pressure in coalbeds:A new model[J]. SPE Reservoir Evaluation & Engineering,1998,1(6):539-544.

[24] CHEN Yuexia,XU Jiang,CHU Tingxiang,et al. The evolution of parameters during CBM drainage in different regions[J], Transport in Porous Media,2017,120(113):83-100.

[25] CHEN Yuexia,XU Jiang,PENG Shoujian,et al. A gas-solid-liquid coupling model of coal seams and the optimization of gas drainage boreholes[J].Energies,2018,11(3):560.