High-efficiency gas extraction technology of staged fracturing roof with sand of underground broken and soft coal seam
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摘要: 碎软煤层瓦斯治理常采用的底板穿层钻孔抽采瓦斯方式存在掘进工程量大、治理周期长、钻孔揭煤段短、抽采治理效果受限等问题，顺层短孔抽采方式存在成孔性差、抽采钻孔短、抽采区域小等问题。通过统计淮北、淮南、焦作、晋城、阳泉5个典型碎软煤层矿区煤层及其顶底板围岩力学参数和地应力，可得顶板岩层弹性模量为碎软煤层的2.56~6.71倍，泊松比为煤层的0.48~0.84倍，分析认为碎软煤层顶板岩层具有高弹性模量、低泊松比特征，顶板较碎软煤层更易压裂改造。参考地面煤层气水平井顶板加砂分段压裂思路，提出了井下碎软煤层顶板加砂分段压裂瓦斯抽采思路，即在煤层顶板稳定岩层中施工定向长钻孔（与煤层距离一般小于10 m），对钻孔由里向外逐段携砂压裂，形成以定向长钻孔将岩层完全联通、煤岩层中压裂缝网将煤层充分沟通的多级缝网，通过支撑剂保障缝网处于开启状态，实现碎软煤层瓦斯顶板定向长钻孔大区域高效抽采。建立了山西新景矿煤业有限责任公司某工作面3号煤层顶板加砂压裂地质模型，采用FracproPT软件对煤层及顶板水力加砂压裂进行数值模拟，得出顶板压裂裂缝在垂直方向上主要向煤层延伸，在水平方向上压裂缝长为煤层压裂缝长的3.49倍，表明碎软煤层顶板间接压裂较煤层直接压裂效果更好。在该工作面3号煤层顶板施工2个609 m定向长钻孔进行水力加砂分段压裂瓦斯抽采工程应用试验，2个钻孔压裂影响半径为20~38 m，压裂钻孔瓦斯抽采纯量分别为1 025.11，2 810.60 m3/d，百米瓦斯抽采纯量为同区域顺层未压裂钻孔的5.6~15.4倍，实现了碎软煤层大区域瓦斯高效抽采。Abstract: The gas extraction method of floor cross-layer drilling commonly used in gas control of broken and soft coal seam has problems such as large excavation quantity, long control period, short coal uncovering section of drilling, limited extraction control effect and so on. The gas extraction method of bedding short hole has problems such as poor drill-forming property, short extraction drilling hole, small extraction area and so on. This paper makes statistics on mechanical parameters and in-situ stress of coal seams and their roof and floor surrounding rocks in five typical broken and soft coal seam mining areas in Huaibei, Huainan, Jiaozuo, Jincheng and Yangquan. It is concluded that the elastic modulus of roof rock is 2.56-6.71 times of that of the broken and soft coal seam. The Poisson's ratio is 0.48-0.84 times of that of the coal seam. The analysis shows that roof rock of broken and soft coal seam is characterized by high elastic modulus and low Poisson's ratio. The roof is easier to be fractured than broken and soft coal seam. Referring to the idea of staged fracturing roof with sand of the horizontal borehole of surface coalbed methane, the idea of gas extraction by staged fracturing roof with sand of underground broken and soft coal seam is put forward. The directional long boreholes in stable strata of coal seam roof are constructed. The boreholes are generally less than 10 m away from the coal seam. The sand-carrying fracturing shall be carried out from the inside to the outside section by section in the boreholes. It will form a multi-stage fracture network in which the rock layer fully connects through directional long holes and the coal seam fully connects through fracture network in coal strata. The proppant is used to ensure that the fracturing network is in open state, so as to realize efficient gas extraction in a large area by the directional long hole in roof of broken and soft coal seam. The geological model of fracturing roof with sand in No.3 coal seam of a working face in Shanxi Xinjing Coal Industry Co., Ltd. is established. The numerical simulation of hydraulic fracturing coal seam and roof with sand is carried out by using FracproPT software. The result shows that the fracturing cracks in roof mainly extend to the coal seam in vertical direction. The length of fracturing cracks in roof in horizontal direction is 3.49 times of that of fracturing cracks in coal seam. This result shows that indirectly fracturing roof of broken and soft coal seam is better than directly fracturing the coal seam. Two 609 m directional long boreholes are drilled in roof of the No.3 coal seam in the working face to carry out gas extraction engineering application test of hydraulic staged fracturing with sand. The fracturing influence radius of the two boreholes is 20-38 m. The gas extraction pure amount of the fracturing holes is 1 025.11 m3/d and 2 810.60 m3/d respectively. The gas extraction pure amount of 100 m is 5.6-15.4 times of that of bedding un-fracturing boreholes in the same area. This study realizes high-efficiency gas extraction in a large area of broken and soft coal seam.
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图 1 井下碎软煤层顶板加砂分段压裂瓦斯高效抽采
Figure 1. Efficient gas extraction by staged fracturing roof with sand of underground broken and soft coal seam
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图 2 煤层及顶板水力加砂压裂地质模型
Figure 2. Geological model for hydraulic fracturing coal seam and roof with sand
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图 3 煤层水力加砂压裂模拟裂缝形态
Figure 3. Simulated crack shape of hydraulic fracturing coal seam with sand
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图 4 顶板水力加砂压裂模拟裂缝形态
Figure 4. Simulated crack shape of hydraulic fracturing roof with sand
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图 6 典型压裂段泵注压力与排量变化曲线
Figure 6. Variation curves of pump injection pressure and displacement of typical fracturing sections
表 1 典型碎软煤层矿区煤层与顶底板岩层力学参数及地应力
Table 1 Mechanics parameters and in-situ stress of coal, roof rock and floor rock in typical broken and soft coal seam mines
矿区及
煤层煤岩类型 埋深/m 厚度/m 弹性模量
/GPa泊松比 最小水平
主应力/MPa最大主应力（垂向应力）/MPa 淮北矿区
8号煤砂质泥岩（顶板） 724.90 4.30 26.00 0.27 8.97 16.95 8号煤层 730.30 10.20 7.20 0.40 7.81 17.09 砂质泥岩（底板） 740.50 0.80 19.50 0.30 10.23 17.17 淮南矿区
13号煤砂岩（顶板） 809.72 5.00 3.09 0.28 10.02 18.96 13号煤层 815.40 2.80 0.70 0.37 8.75 19.05 砂岩（底板） 820.45 4.25 4.68 0.25 11.30 19.18 焦作矿区
2号煤砂岩（顶板） 1 215.05 2.30 3.12 0.27 13.22 28.16 2号煤层 1 217.35 6.80 1.22 0.36 11.60 28.22 泥岩（底板） 1 224.15 2.50 2.02 0.28 13.37 28.37 晋城矿区
3号煤砂岩（顶板） 725.41 37.79 2.36 0.32 10.84 15.80 3号煤层 763.20 4.69 0.85 0.38 9.70 15.90 砂岩（底板） 770.40 7.20 2.52 0.29 10.54 15.80 阳泉矿区
3号煤砂岩（顶板） 508.45 7.40 14.10 0.13 6.57 12.81 3号煤层 515.85 2.10 2.10 0.27 5.50 12.88 泥岩（底板） 521.13 5.28 1.85 0.16 6.65 13.01 
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表 2 煤层和顶板水力加砂压裂数值模拟参数
Table 2 Numerical simulation parameters of hydraulic fracturing coal seam and roof with sand
钻孔裸眼
段长度/m泵注排量/
（m3·min−1）前置液
体积/m3携砂液
体积/m3顶替液
体积/m3加砂量/
m3砂比/
%10 1 35 105 35 2.1 2
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表 3 分段压裂施工参数
Table 3 Construction parameters of staged fracturing
钻孔 压裂
段压裂液
体积/m3压力/
MPa核桃壳砂
质量/tKCl
质量/t杀菌剂
质量/t砂比
/%1号
钻孔1 153.76 25.7~29.6 1.76 0.90 0.045 2.05 2 157.99 27.2~29.4 1.85 0.97 0.085 2.02 3 177.04 27.3~29.1 2.37 1.01 0.106 2.10 4 159.70 21.3~25.3 2.41 1.23 0.112 2.22 5 160.36 16.6~21.7 2.39 1.26 0.110 2.23 6 155.07 18.2~22.6 2.33 1.33 0.132 2.23 小计 963.92 − 13.11 6.70 0.590 − 2号
钻孔1 170.14 22.4~28.1 2.22 1.76 0.117 2.21 2 194.94 22.2~29.3 2.01 2.08 0.139 2.12 3 189.38 25.2~27.9 2.34 1.56 0.104 2.36 4 166.48 24.2~27.6 2.02 1.48 0.098 2.35 5 181.05 22.2~27.4 2.78 1.76 0.117 2.33 6 176.62 19.5~27.5 2.18 1.67 0.111 2.36 7 179.71 22.1~25.9 1.79 1.44 0.096 2.22 8 174.86 21.2~28.0 2.02 1.67 0.111 2.43 9 176.31 21.2~27.8 2.50 1.65 0.110 2.36 10 235.11 23.3~26.5 3.49 2.13 0.142 2.56 小计 1 844.60 − 23.36 17.20 1.146 −
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[1] 王恩元,张国锐,张超林,等. 我国煤与瓦斯突出防治理论技术研究进展与展望[J]. 煤炭学报,2022,47(1):297-322. DOI: 10.13225/j.cnki.jccs.yg21.1846 WANG Enyuan,ZHANG Guorui,ZHANG Chaolin,et al. Research progress and prospect on theory and technology for coal and gas outburst control and protection in China[J]. Journal of China Coal Society,2022,47(1):297-322. DOI: 10.13225/j.cnki.jccs.yg21.1846
[2] 李泉新,方俊,褚志伟,等. 青龙煤矿碎软煤层顺层定向钻孔钻进试验研究[J]. 工矿自动化,2018,44(11):1-6. LI Quanxin,FANG Jun,CHU Zhiwei,et al. Drilling experiment research on bedding directional drilling of soft-fragmentized coal seam of Qinglong Coal Mine[J]. Industry and Mine Automation,2018,44(11):1-6.
[3] 张倩,栗磊. 水力造穴增透预抽在掘进面区域防突中的应用试验[J]. 煤炭工程,2019,51(11):65-68. ZHANG Qian,LI Lei. Application test of permeability enhancement by hydraulic jet cavity in regional outburst prevention of heading face[J]. Coal Engineering,2019,51(11):65-68.
[4] 孙四清,张俭,安鸿涛. 松软突出煤层穿层洞穴完井钻孔瓦斯抽采实践[J]. 煤炭科学技术,2012,40(2):49-51,55. DOI: 10.13199/j.cst.2012.02.54.sunsq.020 SUN Siqing,ZHANG Jian,AN Hongtao. Practices on gas drainage with cavity completion borehole passing through soft and outburst seam[J]. Coal Science and Technology,2012,40(2):49-51,55. DOI: 10.13199/j.cst.2012.02.54.sunsq.020
[5] 孙大发,陈久福,龙建明,等. 高压水力压裂技术在石门揭煤中的试验研究[J]. 煤炭科学技术,2013,41(增刊2):163-165. DOI: 10.13199/j.cnki.cst.2013.s2.082 SUN Dafa,CHEN Jiufu,LONG Jianming,et al. Experimental study on high pressure hydraulic fracturing technology to uncover coal in cross-cut[J]. Coal Science and Technology,2013,41(S2):163-165. DOI: 10.13199/j.cnki.cst.2013.s2.082
[6] 蔡峰,刘泽功. 深部低透气性煤层上向穿层水力压裂强化增透技术[J]. 煤炭学报,2016,41(1):113-119. DOI: 10.13225/j.cnki.jccs.2015.9014 CAI Feng,LIU Zegong. Simulation and experimental research on upward cross-seams hydraulic fracturing in deep and low-permeability coal seam[J]. Journal of China Coal Society,2016,41(1):113-119. DOI: 10.13225/j.cnki.jccs.2015.9014
[7] 孙四清,郑凯歌. 井下高压水射流切割煤层增透效果数值模拟[J]. 煤田地质与勘探,2017,45(2):45-49. DOI: 10.3969/j.issn.1001-1986.2017.02.008 SUN Siqing,ZHENG Kaige. Numerical simulation study on permeability enhancement effect of high pressure water cutting coal seam[J]. Coal Geology & Exploration,2017,45(2):45-49. DOI: 10.3969/j.issn.1001-1986.2017.02.008
[8] 姚宁平,张杰,李泉新,等. 煤矿井下梳状定向孔钻进技术研究与实践[J]. 煤炭科学技术,2012,40(5):30-34. DOI: 10.13199/j.cst.2012.05.34.yaonp.016 YAO Ningping,ZHANG Jie,LI Quanxin,et al. Researchment and application of comb type directional borehole drilling technology in underground mine[J]. Coal Science and Technology,2012,40(5):30-34. DOI: 10.13199/j.cst.2012.05.34.yaonp.016
[9] 李泉新,石智军,史海岐. 煤矿井下定向钻进工艺技术的应用[J]. 煤田地质与勘探,2014,42(2):85-88,92. DOI: 10.3969/j.issn.1001-1986.2014.02.018 LI Quanxin,SHI Zhijun,SHI Haiqi. The application of directional drilling technology in coal mine[J]. Coal Geology & Exploration,2014,42(2):85-88,92. DOI: 10.3969/j.issn.1001-1986.2014.02.018
[10] 孙四清,张群,闫志铭,等. 碎软低渗高突煤层井下长钻孔整体水力压裂增透工程实践[J]. 煤炭学报,2017,42(9):2337-2344. DOI: 10.13225/j.cnki.jccs.2017.0689 SUN Siqing,ZHANG Qun,YAN Zhiming,et al. Practice of permeability enhancement through overall hydraulic fracturing of long hole in outburst-prone soft crushed coal seam with low permeability[J]. Journal of China Coal Society,2017,42(9):2337-2344. DOI: 10.13225/j.cnki.jccs.2017.0689
[11] 牟全斌. 井下穿层长钻孔水力压裂强化增透技术[J]. 中国安全生产科学技术,2017,13(8):164-169. DOI: 10.11731/j.issn.1673-193x.2017.08.026 MOU Quanbin. Strengthened permeability enhancement technology by hydraulic fracturing for underground layer-through long borehole[J]. Journal of Safety Science and Technology,2017,13(8):164-169. DOI: 10.11731/j.issn.1673-193x.2017.08.026
[12] 陈冬冬,孙四清,张俭,等. 井下定向长钻孔水力压裂煤层增透技术体系与工程实践[J]. 煤炭科学技术,2020,48(10):84-89. DOI: 10.13199/j.cnki.cst.2020.10.009 CHEN Dongdong,SUN Siqing,ZHANG Jian,et al. Technical system and engineering practice of coal seam permeability improvement through underground directional long borehole hydraulic fracturing[J]. Coal Science and Technology,2020,48(10):84-89. DOI: 10.13199/j.cnki.cst.2020.10.009
[13] 郑凯歌. 碎软低透煤层底板梳状长钻孔分段水力压裂增透技术研究[J]. 采矿与安全工程学报,2020,37(2):272-281. DOI: 10.13545/j.cnki.jmse.2020.02.007 ZHENG Kaige. Permeability improving technology by sectional hydraulic fracturing for comb-like long drilling in floor of crushed and soft coal seam with low permeability[J]. Journal of Mining & Safety Engineering,2020,37(2):272-281. DOI: 10.13545/j.cnki.jmse.2020.02.007
[14] ZHANG Jingfei,SUN Siqing,LI Shugang,et al. Research and engineering practice of high-efficiency gas extraction technology by hydraulic fracturing:a case study of Huanglong Coalfeld in China[J]. Arabian Journal of Geosciences,2022,15:1012. DOI: 10.1007/s12517-022-10299-9
[15] 贾秉义,陈冬冬,吴杰,等. 煤矿井下顶板梳状长钻孔分段压裂强化瓦斯抽采实践[J]. 煤田地质与勘探,2021,49(2):70-76. DOI: 10.3969/j.issn.1001-1986.2021.02.009 JIA Bingyi,CHEN Dongdong,WU Jie,et al. Practice of enhanced gas extraction by staged fracturing with comb-shaped long hole in coal mine roof[J]. Coal Geology & Exploration,2021,49(2):70-76. DOI: 10.3969/j.issn.1001-1986.2021.02.009
[16] 张群,葛春贵,李伟,等. 碎软低渗煤层顶板水平井分段压裂煤层气高效抽采模式[J]. 煤炭学报,2018,43(1):150-159. DOI: 10.13225/j.cnki.jccs.2017.1422 ZHANG Qun,GE Chungui,LI Wei,et al. A new model and application of coalbed methane high efficiency production from broken soft and low permeable coal seam by roof strata-in horizontal well and staged hydraulic fracture[J]. Journal of China Coal Society,2018,43(1):150-159. DOI: 10.13225/j.cnki.jccs.2017.1422
[17] 巫修平,张群. 碎软低渗煤层顶板水平井分段压裂裂缝扩展规律及控制机制[J]. 天然气地球科学,2018,29(2):268-276. WU Xiuping,ZHANG Qun. Research on controlling mechanism of fracture propagation of multi-stage hydraulic fracturing horizontal well in roof of broken soft and low permeability coal seam[J]. Natural Gas Geoscience,2018,29(2):268-276.
[18] 许耀波,郭盛强. 软硬煤复合的煤层气水平井分段压裂技术及应用[J]. 煤炭学报,2019,44(4):1169-1177. DOI: 10.13225/j.cnki.jccs.2018.1691 XU Yaobo,GUO Shengqiang. Technology and application of staged fracturing in coalbed methane horizontal well of soft and hard coal composite coal seam[J]. Journal of China Coal Society,2019,44(4):1169-1177. DOI: 10.13225/j.cnki.jccs.2018.1691
[19] 陈诚,雷征东,房茂军,等. 致密砂岩储层可压性评价与极限参数压裂技术[J]. 科学技术与工程,2022,22(16):6400-6407. DOI: 10.3969/j.issn.1671-1815.2022.16.004 CHEN Cheng,LEI Zhengdong,FANG Maojun,et al. Tight sandstone reservoir compressibility evaluation and limit parameter fracturing technology[J]. Science Technology and Engineering,2022,22(16):6400-6407. DOI: 10.3969/j.issn.1671-1815.2022.16.004
[20] 姜在炳,李浩哲,许耀波,等. 煤层顶板分段压裂水平井地质适应性分析与施工参数优化[J]. 煤田地质与勘探,2022,50(3):183-192. DOI: 10.12363/issn.1001-1986.22.01.0037 JIANG Zaibing,LI Haozhe,XU Yaobo,et al. Geological adaptability analysis and operational parameter optimization for staged fracturing horizontal wells in coal seam roof[J]. Coal Geology & Exploration,2022,50(3):183-192. DOI: 10.12363/issn.1001-1986.22.01.0037
[21] 雷毅,武文宾,陈久福. 松软煤层井下水力压裂增透技术及应用[J]. 煤矿开采,2015,20(1):105-107. DOI: 10.13532/j.cnki.cn11-3677/td.2015.01.031 LEI Yi,WU Wenbin,CHEN Jiufu. Technology of underground permeability improvement of soft coal-seam with hydrofracture and its application[J]. Coal Mining Technology,2015,20(1):105-107. DOI: 10.13532/j.cnki.cn11-3677/td.2015.01.031
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