低渗透性煤层注液态CO_2置换驱替CH_4试验
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摘要
针对低渗透性煤层瓦斯难以抽采的问题,结合液态CO_2低温、低黏、渗流阻力小、相变增压等特性,提出低渗透性煤层注液态CO_2置换驱替CH_4技术。在韩城矿区桑树坪二号井开展煤层注液态CO_2置换驱替CH_4工业性试验,开发了压注工艺系统,确定了压注关键性参数,判定了CO_2置换驱替CH_4技术效果。试验结果表明:液态CO_2压注时压力呈现波动特性,起始升压速率较快,达到2.5MPa左右时趋于稳定;压注管路瞬时流量为0.6~1.4m~3/h,累计压注液态CO_2为6.0m~3;以压注过程中检验孔内CO_2体积分数为指标,判定试验有效影响半径达到18m。试验区域瓦斯抽采体积分数是原始体积分数的2.5倍,抽采纯量是原始纯量的3.5倍,相比瓦斯抽采效率提高。
This paper is to solve the gas drainage problem of low permeability coal seam.Based on the characteristics of liquid carbon dioxide with low temperature,viscosity,percolation resistance and phase change pressurization,the liquid carbon dioxide enhanced methane recovery technology was proposed to improve the gas drainage efficiency.Liquid carbon dioxide injection test was carried out at Sangshuping No.2 mine shaft,Hancheng mining area,and by which injection process was developed,the key parameters were determined and the methane extraction efficiency influenced by carbon dioxide was examined.The results show that the pressure of injecting is fluctuated.Initially,injecting pressure rises fast and then keeps stable when rising to 2.5 MPa.The flow rate of injection maintains from 0.6 m~3/h to 1.4 m~3/h and the total cumulant of liquid carbon dioxide is 6.0 m~3.The concentration of carbon dioxide in the test borehole is taken as index,and it's found that the influence radius of the test is 18 m.The methane concentration andthe purity in the test area are 2.5 and 3.5 times of those in the original data respectively,which proves the proposed technology enhances the gas extraction efficiency.
This paper is to solve the gas drainage problem of low permeability coal seam.Based on the characteristics of liquid carbon dioxide with low temperature,viscosity,percolation resistance and phase change pressurization,the liquid carbon dioxide enhanced methane recovery technology was proposed to improve the gas drainage efficiency.Liquid carbon dioxide injection test was carried out at Sangshuping No.2 mine shaft,Hancheng mining area,and by which injection process was developed,the key parameters were determined and the methane extraction efficiency influenced by carbon dioxide was examined.The results show that the pressure of injecting is fluctuated.Initially,injecting pressure rises fast and then keeps stable when rising to 2.5 MPa.The flow rate of injection maintains from 0.6 m~3/h to 1.4 m~3/h and the total cumulant of liquid carbon dioxide is 6.0 m~3.The concentration of carbon dioxide in the test borehole is taken as index,and it's found that the influence radius of the test is 18 m.The methane concentration andthe purity in the test area are 2.5 and 3.5 times of those in the original data respectively,which proves the proposed technology enhances the gas extraction efficiency.
引文
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[13]王兆丰,孙小明,陆庭侃,等.液态CO2相变致裂强化瓦斯预抽试验研究[J].河南理工大学学报(自然科学版),2015,34(1):1-5.WANG Zhaofeng,SUN Xiaoming,LU Tingkan,et al.Experiment research on strengthening gas drainage effect with fracturing technique by liquid CO2 phase transition[J].Journal of Henan Polytechnic University(NaturalScience),2015,34(1):1-5.(in Chinese)
[14]Wen H,Li Z B,Deng J,et al.Influence on coal pore structure during liquid CO2-ECBM process for CO2utilization[J].Journal of CO2 Utilization,2017,21:543-552.
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[16]Xu J Z,Zhai C,Liu SM,et al.Feasibility investigation of cryogenic effect from liquid carbon dioxide multi cycle fracturing technology in coal-bed methane recovery[J].Fuel,2017,206:371-380.
[17]张遵国.煤吸附/解吸变形特征及其影响因素研究[D].重庆:重庆大学,2015.ZHANG Zunguo.Study on characteristics of adsorption/desorption-induced deformation and its influencing factors[D].Chongqing:Chongqing University,2015.(in Chinese)
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[19]马志宏,郭勇义,吴世跃.注入二氧化碳及氮气驱替煤层气机理的实验研究[J].太原理工大学学报,2001,32(4):335-338.MA Zhihong,GUO Yongyi,WU Shiyue.Experimental study on the mechanism of injecting carbon dioxide and nitrogen to displace coal-bed methane[J].Journal of Taiyuan University of Technology,2001,32(4):335-338.(in Chinese)
[2]袁志刚,任梅清,沈永红,等.穿层钻孔煤巷条带水力压裂防突技术及应用[J].重庆大学学报,2016,39(1):72-78.YUAN Zhigang,REN Meiqing,SHEN Yonghong,et al.Hydraulic fracturing technology by drilling through strata foroutburst prevention in coal roadway strips and its application[J].Journal of Chongqing University,2016,39(1):72-78.(in Chinese)
[3]林柏泉.矿井瓦斯防治理论与技术[M].第二版.徐州:中国矿业大学出版社,2010:253-256.LIN Baiquan.Gas prevention and control theory and technology of mine[M].2ndedition.Xuzhou:China University of Mining and Technology Press,2010:253-256.(in Chinese)
[4]Lin B Q,Li H,Yuan D S,et al.Development and application of an efficient gas extraction model for low-rank high-gas coalbeds[J].International Journal of Coal Science and Technology,2015,2(1):76-83.
[5]赵龙,王兆丰,孙矩正,等.液态CO2相变致裂增透技术在高瓦斯低透煤层的应用[J].煤炭科学技术,2016,44(3):75-79.ZHAO Long,WANG Zhaofeng,SUN Juzheng,et al.Application of permeability improvement technology with liquid CO2phase transition fracturing to high gassy and low permeability seam[J].Coal Science and Technology,2016,44(3):75-79.(in Chinese)
[6]杜春志,茅献彪,卜万奎.水力压裂时煤层缝裂的扩展分析[J].采矿与安全工程学报,2008,25(2):231-234.DU Chunzhi,MAO Xianbiao,BUWankui.Analysis of fracture propagation in coal seams during hydraulic fracturing[J].Journal of Mining&Safety Engineering,2008,25(2):231-234.(in Chinese)
[7]赵源,曹树刚,李勇,等.本煤层水压致裂增透范围分析[J].采矿与安全工程学报,2015,32(4):644-650.ZHAO Yuan,CAOShugang,LI Yong,et al.The analysis of antireflection range in coal seam hydraulic fracturing[J].Journal of Mining&Safety Engineering,2015,32(4):644-650.(in Chinese)
[8]卢义玉,葛兆龙,李晓红,等.自激振荡脉冲水射流割缝新技术在逢春煤矿石门揭煤中的应用研究[J].重庆大学学报,2008,31(suppl1):98-100.LU Yiyu,GE Zhaolong,LI Xiaohong,et al.New technology of self-excited oscillation pulsed jet slotting in coal mine of cross-hole FengChun applied research in coal[J].Journal of Chongqing University,2008,31(S1):98-100.(in Chinese)
[9]王兆丰,孙小明,陆庭侃,等.液态CO2相变致裂强化瓦斯预抽试验研究[J].河南理工大学学报(自然科学版),2015,1(34):1-5.WANG Zhaofeng,SUN Xiaoming,LU Tingkan,et al.Experiment research on enhancing gas drainage effect with fracturing technique by liquid CO2phase transition[J].Journal of Henan Polytechnic University(Natural Science),2015,1(34):1-5.(in Chinese)
[10]朱帅虎.低渗透性煤层粉乳炸药预裂爆破增透实验及工艺研究[D].北京:中国矿业大学(北京),2014.ZHU Shuaihu.The study on permeability increasing experiments and techniques by deep hole pre-splitting blasting with powder-emulsionin explosive in low permeability coal seam[D].Beijing:China University of Mining and Technology,Beijing,2014.(in Chinese)
[11]黄文尧,颜事龙,刘泽功,等.煤矿瓦斯抽采水胶药柱在煤层深孔爆破中的研究与应用[J].煤炭学报,2012,37(3):472-476.HUANG Wenyao,YAN Shilong,LIU Zegong,et al.Research and application of water gel explosive grain on coal mine gas extraction in coal seam deep hole blasting[J].Journal of China Coal Society,2012,37(3):472-476.(in Chinese)
[12]文虎,李珍宝,王振平,等.煤层液态CO2压裂增透过程及裂隙扩展特征试验[J].煤炭学报,2016,41(11):2793-2799.WEN Hu,LI Zhenbao,WANG Zhenping,et al.Experiment on the liquid CO2 fracturing process for increasing permeability and the characteristic of crack propagation in coal seam[J].Journal of China Coal Society,2016,41(11):2793-2799.
[13]王兆丰,孙小明,陆庭侃,等.液态CO2相变致裂强化瓦斯预抽试验研究[J].河南理工大学学报(自然科学版),2015,34(1):1-5.WANG Zhaofeng,SUN Xiaoming,LU Tingkan,et al.Experiment research on strengthening gas drainage effect with fracturing technique by liquid CO2 phase transition[J].Journal of Henan Polytechnic University(NaturalScience),2015,34(1):1-5.(in Chinese)
[14]Wen H,Li Z B,Deng J,et al.Influence on coal pore structure during liquid CO2-ECBM process for CO2utilization[J].Journal of CO2 Utilization,2017,21:543-552.
[15]Xu J Z,Zhai C,Liu SM,et al.Pore variation of three different metamorphic coals by multiple freezing-thawing cycles of liquid CO2injection for coal-bed methane recovery[J].Fuel,2017,208:41-51.
[16]Xu J Z,Zhai C,Liu SM,et al.Feasibility investigation of cryogenic effect from liquid carbon dioxide multi cycle fracturing technology in coal-bed methane recovery[J].Fuel,2017,206:371-380.
[17]张遵国.煤吸附/解吸变形特征及其影响因素研究[D].重庆:重庆大学,2015.ZHANG Zunguo.Study on characteristics of adsorption/desorption-induced deformation and its influencing factors[D].Chongqing:Chongqing University,2015.(in Chinese)
[18]De Silva P N K,Ranjith P G.Understanding and application of CO2adsorption capacityestimation models for coal types[J].Fuel,2014,121:250-259.
[19]马志宏,郭勇义,吴世跃.注入二氧化碳及氮气驱替煤层气机理的实验研究[J].太原理工大学学报,2001,32(4):335-338.MA Zhihong,GUO Yongyi,WU Shiyue.Experimental study on the mechanism of injecting carbon dioxide and nitrogen to displace coal-bed methane[J].Journal of Taiyuan University of Technology,2001,32(4):335-338.(in Chinese)