基于煤体各向异性的煤层瓦斯有效抽采区域研究
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摘要
为了探究影响射流割缝钻孔周围有效抽采区域变化的因素,基于煤体的各向异性考虑了瓦斯抽采过程煤体应变场和瓦斯渗流场的耦合作用,探讨了不同垂直地应力、初始瓦斯压力以及初始渗透率等参数对射流割缝钻孔有效抽采区域的影响规律。结果表明:垂直地应力越大,煤体的渗透率越低,有效抽采区域逐渐减小;初始瓦斯压力越大,抽采相同时间后瓦斯压力越难降至0.74 MPa以下,有效抽采区域逐渐减小;初始渗透率越大,煤体裂隙瓦斯流动速度越快,导致在相同抽采负压下有效抽采区域逐渐增大。各向异性煤体的模拟结果与现场测试结果基本相符,证明了各向异性煤层垂直层理方向有效抽采半径是现场布孔的合理指标。
The paper is devoted to explore parameters that affect the effective drainage area around the hydraulic slotting. The coupling effect of the coal strain field and the gas seepage field in gas drainage is studied based on the anisotropy of coal.The influences of different vertical geostress,initial gas pressure,and initial permeability on the effective drainage area of hydraulic slotting are also analyzed.The results show that higher vertical ground stress is associated with lower coal permeability,which leads to the gradual reduction of effective drainage area.The larger the initial gas pressure is,the more difficulty it is to reduce the gas pressure around the borehole to 0.74 MPa or less,with the effective drainage area being gradually reduced. The larger the initial permeability,the higher the gas flow velocity of the coal body fissure,and the effective drainage area gradually increases under the same drainage negative pressure.The simulation results of anisotropic coal body are basically consistent with the field test results,which proves that the effective drainage radius of the anisotropic coal seam vertical bedding direction is a reasonable index of the field hole.
The paper is devoted to explore parameters that affect the effective drainage area around the hydraulic slotting. The coupling effect of the coal strain field and the gas seepage field in gas drainage is studied based on the anisotropy of coal.The influences of different vertical geostress,initial gas pressure,and initial permeability on the effective drainage area of hydraulic slotting are also analyzed.The results show that higher vertical ground stress is associated with lower coal permeability,which leads to the gradual reduction of effective drainage area.The larger the initial gas pressure is,the more difficulty it is to reduce the gas pressure around the borehole to 0.74 MPa or less,with the effective drainage area being gradually reduced. The larger the initial permeability,the higher the gas flow velocity of the coal body fissure,and the effective drainage area gradually increases under the same drainage negative pressure.The simulation results of anisotropic coal body are basically consistent with the field test results,which proves that the effective drainage radius of the anisotropic coal seam vertical bedding direction is a reasonable index of the field hole.
引文
[1]范超军,李胜,罗明坤,等.基于流-固-热耦合的深部煤层气抽采数值模拟[J].煤炭学报,2016,41(12):3076-3085.FAN Chaojun,LI Sheng,LUO Mingkun,et al.Deep CBM extraction numerical simulation based on hydraulic-mechanical-thermal coupled model[J].Journal of China Coal Society,2016,41(12):3076-3085.
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[5]刘厅,林柏泉,邹全乐,等.基于煤层原始瓦斯含量和压力的割缝钻孔有效抽采半径测定[J].煤矿安全,2014,45(8):8-11.LIU Ting,LIN Baiquan,ZOU Quanle,et al.Measurement of effective drainage radius based on primitive gas content and pressure for slotted drilling[J].Safety in Coal Mines,2014,45(8):8-11.
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[7]徐青伟,王兆丰,徐书荣,等.多煤层穿层钻孔瓦斯抽采有效抽采半径测定[J].煤炭科学技术,2015,43(7):83-88.XU Qingwei,WANG Zhaofeng,XU Shurong,et al.Measurement on effective gas drainage radius of boreholes passed through multi seams[J].Coal Science and Technology,2015,43(7):83-88.
[8]林柏泉,赵洋,刘厅,等.水力割缝煤体多场耦合响应规律研究[J].西安科技大学学报,2017,37(5):662-667.LIN Baiquan,ZHAO Yang,LIU Ting,et al.Coupling response law of multi-field in coal seam after hydraulic slotting[J].Journal of Xi’an University of Science and Technology,2017,37(5):662-667.
[9]梁冰,袁欣鹏,孙维吉.本煤层顺层瓦斯抽采渗流耦合模型及应用[J].中国矿业大学学报,2014,43(2):208-213.LIANG Bing,YUAN Xinpeng,SUN Weiji.Seepage coupling model of in-seam gas extraction and its applications[J].Journal of China University of Mining&Technology,2014,43(2):208-213.
[10]岳高伟,王宾宾,曹汉生,等.结构异性煤层顺层钻孔方位对有效抽采半径的影响[J].煤炭学报,2017,42(S1):138-147.YUE Gaowei,WANG Binbin,CAO Hansheng,et al.Influence of effective drainage radius by borehole orientation along seam with anisotropic permeability[J].Journal of China Coal Society,2017,42(S1):138-147.
[11]曾春林,岳高伟,王宾宾,等.基于瓦斯渗透异性的煤层抽采钻孔合理布置[J].重庆大学学报:自然科学版,2018,41(6):102-114.ZENG Chunlin,YUE Gaowei,WANG Binbin,et al.Reasonable layout of drainage boreholes based on anisotropic permeability in coal seam[J].Journal of Chongqing University:Natural Science Edition,2018,41(6):102-114.
[12]LIU Jishan,CHEN Zhongwei,ELSWORTH Derek,et al.Linking gas-sorption induced changes in coal permeability to directional strains through a modulus reduction ratio[J].International Journal of Coal Geology,2010,83(1):21-30.
[13]ROBERTSON Eric P,CHRISTIANSEN Richard L.Modeling laboratory permeability in coal using sorption-lnduced-strain data[J].SPE Reservoir Evaluation&Engineering,2007,10(3):260-269.
[14]ZHAO Yang,LIN Baiquan,LIU Ting,et al.Gas flow field evolution around hydraulic slotted borehole in anisotropic coal[J].Journal of Natural Gas Science and Engineering,2018,58:189-200.
[15]LIU Ting,LIN Baiquan,YANG Wei.Impact of matrix-fracture interactions on coal permeability:model development and analysis[J].Fuel,2017,207:522-532.
[16]ZHANG Hongbin,LIU Jishan,ELSWORTH D.How sorption-induced matrix deformation affects gas flow in coal seams:a new FEmodel[J].International Journal of Rock Mechanics and Mining Sciences,2008,45(8):1226-1236.
[17]范超军,李胜,罗明坤,等.基于流-固-热耦合的深部煤层气抽采数值模拟[J].煤炭学报,2016,41(12):3076-3085.FAN Chaojun,LI Sheng,LUO Mingkun,et al.Deep CBMextraction numerical simulation based on hydraulic-mechanicalthermal coupled model[J].Journal of China Coal Society,2016,41(12):3076-3085.
[18]WANG Liang,LIU Shimin,CHENG Yuanping,et al.Reservoir reconstruction technologies for coalbed methane recovery in deep and multiple seams[J].International Journal of Mining Science and Technology,2017,27(2):277-284.
[2]付建华,程远平.中国煤矿煤与瓦斯突出现状及防治对策[J].采矿与安全工程学报,2007,24(3):253-259.FU Jianhua,CHENG Yuanping.Situation of coal and gas outburst in china and control countermeasures[J].Journal of Mining&Safety Engineering,2007,24(3):253-259.
[3]林柏泉,刘厅,杨威.基于动态扩散的煤层多场耦合模型建立及应用[J].中国矿业大学学报,2018,47(1):32-39.LIN Boquan,LIU Ting,YANG Wei.Solid-gas coupling model for coal seams based on dynamic diffusion and its application[J].Journal of China University of Mining&Technology,2018,47(1):32-39.
[4]李子文,林柏泉,郭明功,等.基于一维径向流动确定钻孔瓦斯抽采有效影响半径[J].煤炭科学技术,2014,42(12):62-64.LI Ziwen,LIN Baiquan,GUO Minggong,et al.Determination on effective influence radius of gas drainage through borehole based on one-dimensional radial flow[J].Coal Science And Technology,2014,42(12):62-64.
[5]刘厅,林柏泉,邹全乐,等.基于煤层原始瓦斯含量和压力的割缝钻孔有效抽采半径测定[J].煤矿安全,2014,45(8):8-11.LIU Ting,LIN Baiquan,ZOU Quanle,et al.Measurement of effective drainage radius based on primitive gas content and pressure for slotted drilling[J].Safety in Coal Mines,2014,45(8):8-11.
[6]季淮君,李增华,杨永良,等.基于瓦斯流场的抽采半径确定方法[J].采矿与安全工程学报,2013,30(6):917-921.JI Huaijun,LI Zenghua,YANG Yongliang,et al.Drainage radius measurement based on gas flow field[J].Journal of Mining and Safety Engineering,2013,30(6):917-921.
[7]徐青伟,王兆丰,徐书荣,等.多煤层穿层钻孔瓦斯抽采有效抽采半径测定[J].煤炭科学技术,2015,43(7):83-88.XU Qingwei,WANG Zhaofeng,XU Shurong,et al.Measurement on effective gas drainage radius of boreholes passed through multi seams[J].Coal Science and Technology,2015,43(7):83-88.
[8]林柏泉,赵洋,刘厅,等.水力割缝煤体多场耦合响应规律研究[J].西安科技大学学报,2017,37(5):662-667.LIN Baiquan,ZHAO Yang,LIU Ting,et al.Coupling response law of multi-field in coal seam after hydraulic slotting[J].Journal of Xi’an University of Science and Technology,2017,37(5):662-667.
[9]梁冰,袁欣鹏,孙维吉.本煤层顺层瓦斯抽采渗流耦合模型及应用[J].中国矿业大学学报,2014,43(2):208-213.LIANG Bing,YUAN Xinpeng,SUN Weiji.Seepage coupling model of in-seam gas extraction and its applications[J].Journal of China University of Mining&Technology,2014,43(2):208-213.
[10]岳高伟,王宾宾,曹汉生,等.结构异性煤层顺层钻孔方位对有效抽采半径的影响[J].煤炭学报,2017,42(S1):138-147.YUE Gaowei,WANG Binbin,CAO Hansheng,et al.Influence of effective drainage radius by borehole orientation along seam with anisotropic permeability[J].Journal of China Coal Society,2017,42(S1):138-147.
[11]曾春林,岳高伟,王宾宾,等.基于瓦斯渗透异性的煤层抽采钻孔合理布置[J].重庆大学学报:自然科学版,2018,41(6):102-114.ZENG Chunlin,YUE Gaowei,WANG Binbin,et al.Reasonable layout of drainage boreholes based on anisotropic permeability in coal seam[J].Journal of Chongqing University:Natural Science Edition,2018,41(6):102-114.
[12]LIU Jishan,CHEN Zhongwei,ELSWORTH Derek,et al.Linking gas-sorption induced changes in coal permeability to directional strains through a modulus reduction ratio[J].International Journal of Coal Geology,2010,83(1):21-30.
[13]ROBERTSON Eric P,CHRISTIANSEN Richard L.Modeling laboratory permeability in coal using sorption-lnduced-strain data[J].SPE Reservoir Evaluation&Engineering,2007,10(3):260-269.
[14]ZHAO Yang,LIN Baiquan,LIU Ting,et al.Gas flow field evolution around hydraulic slotted borehole in anisotropic coal[J].Journal of Natural Gas Science and Engineering,2018,58:189-200.
[15]LIU Ting,LIN Baiquan,YANG Wei.Impact of matrix-fracture interactions on coal permeability:model development and analysis[J].Fuel,2017,207:522-532.
[16]ZHANG Hongbin,LIU Jishan,ELSWORTH D.How sorption-induced matrix deformation affects gas flow in coal seams:a new FEmodel[J].International Journal of Rock Mechanics and Mining Sciences,2008,45(8):1226-1236.
[17]范超军,李胜,罗明坤,等.基于流-固-热耦合的深部煤层气抽采数值模拟[J].煤炭学报,2016,41(12):3076-3085.FAN Chaojun,LI Sheng,LUO Mingkun,et al.Deep CBMextraction numerical simulation based on hydraulic-mechanicalthermal coupled model[J].Journal of China Coal Society,2016,41(12):3076-3085.
[18]WANG Liang,LIU Shimin,CHENG Yuanping,et al.Reservoir reconstruction technologies for coalbed methane recovery in deep and multiple seams[J].International Journal of Mining Science and Technology,2017,27(2):277-284.