组合溶剂作用下高阶煤的表面性质和孔隙结构变化研究
|
摘要
为了对比分析组合压裂液中不同溶剂作用下高阶煤的表面性质和孔隙结构变化特征,分别以有机溶剂(THF)和无机酸(HCl)、有机溶剂(CS_2)和强氧化剂(ClO_2)为组合,对山西长治的高阶煤进行不同顺序试验,并借助接触角和低温液氮吸附试验。结果表明:有机溶剂+无机溶剂作用下的萃取(溶出)率要高于无机溶剂+有机溶剂作用下的,其中有机溶剂的萃取率远大于无机溶剂的溶出率; HCl作用后的煤样接触角减小,表面张力增大,润湿性增强,而有机溶剂和ClO_2作用后的煤样则相反;不同溶剂作用后煤样的BET比表面积和BJH孔容均显著增大,其中有机溶剂+无机溶剂作用下的增大程度大于无机溶剂+有机溶剂作用下的;各种溶剂对煤样均具有扩孔效果,特别是对小孔径段效果最为显著。相比而言,两种溶剂作用后煤样的扩孔效果要明显优于一种溶剂作用后的,且CS_2+ClO_2组合溶剂最为显著。因此,将CS_2溶剂和ClO_2溶剂分别作为压裂液中的前置液和携砂液,可更好地改造煤储层的透气性。
In order to study the effect of different solvents in the combined fracturing fluid on the surface property and pore sturcture of high rank coal,coal samples from Changzhi were extracted or dissolved in different orders by combined solvents,including organic solvent (THF) and inorganic acid (HCl),organic solvent (CS_2)and strong oxidant (ClO_2). By means of contact angel and low temperature liquid nitrogen adsorption experiments,the characteristics of surface property and porosity changes during the process of solvent disposition were comparatively studied. The results showed that the yields of solvent extraction (dissolution) in the sequence of organic solvent and inorganic solvent disposition was higher than that of inorganic solvent and organic solvent,and the extraction yield of organic solvent was much higher than that of inorganic solvent. With the coal-water contact angel decreasing,the surface tension and hydrophily for the HCl treated coal increased. all the individual changes to organic solvents and ClO_2 treated coal were reversal. After the disposition of different solvents,the BET specific surface area and BJH specific pore volume of coals increased significantly,and the increase of organic solvent and inorganic solvent disposition of coals was larger than that of inorganic solvent and organic solvent. All of the solvents used in the experiment had pore-expanding effect,especially for the pores with smaller diameter. By comparison,the reconstruction effect on the pores with two kinds of solvents disposition was better than that with one kind of solvent disposition for coals. For the combined solvents,CS_2 and ClO_2 had the most significant reconstruction effect on pores,while the result of THF and HCl was not obvious. Therefore,the solvents of CS_2 and ClO_2 as pre-fluid or carrying fluid of fracturing fluid would have better reconstruction effect on coal reservoir.
In order to study the effect of different solvents in the combined fracturing fluid on the surface property and pore sturcture of high rank coal,coal samples from Changzhi were extracted or dissolved in different orders by combined solvents,including organic solvent (THF) and inorganic acid (HCl),organic solvent (CS_2)and strong oxidant (ClO_2). By means of contact angel and low temperature liquid nitrogen adsorption experiments,the characteristics of surface property and porosity changes during the process of solvent disposition were comparatively studied. The results showed that the yields of solvent extraction (dissolution) in the sequence of organic solvent and inorganic solvent disposition was higher than that of inorganic solvent and organic solvent,and the extraction yield of organic solvent was much higher than that of inorganic solvent. With the coal-water contact angel decreasing,the surface tension and hydrophily for the HCl treated coal increased. all the individual changes to organic solvents and ClO_2 treated coal were reversal. After the disposition of different solvents,the BET specific surface area and BJH specific pore volume of coals increased significantly,and the increase of organic solvent and inorganic solvent disposition of coals was larger than that of inorganic solvent and organic solvent. All of the solvents used in the experiment had pore-expanding effect,especially for the pores with smaller diameter. By comparison,the reconstruction effect on the pores with two kinds of solvents disposition was better than that with one kind of solvent disposition for coals. For the combined solvents,CS_2 and ClO_2 had the most significant reconstruction effect on pores,while the result of THF and HCl was not obvious. Therefore,the solvents of CS_2 and ClO_2 as pre-fluid or carrying fluid of fracturing fluid would have better reconstruction effect on coal reservoir.
引文
[1]秦勇,徐志伟,张井.煤级煤孔径结构的自然分类及其应用[J].煤炭学报,1995,20(3):266-271.QIN Y,XU Z W,ZHANG J.Natural classification of the high-rank coal pore structure and its application[J].Journal of China Coal Society,1995,20(3):266-271.
[2]王红岩,李景明,刘洪林,等.中国高煤阶煤层气成藏特征[J].天然气工业,2005,25(12):31-33.WANG H Y,LI J M,LIU H L,et al.The characteristics of high rank coal bed methane reservoir[J].Natural Gas Industry,2005,25(12):31-33.
[3]PENG W,MAO X B,LIN J B,et al.Study of the borehole hydraulic fracturing and the principle of gas seepage in the coal seam[J].Procedia Earth&Planetary Science,2009,1(1):1561-1573.
[4]MIDDLETON R S,CAREY J W,CURRIER R P,et al.Shale gas and non-aqueous fracturing fluids:Opportunities and challenges for supercritical CO2[J].Applied Energy,2015,147(3):500-509.
[5]李亭,杨琦,冯文光,等.煤层气新型清洁压裂液室内研究及现场应用[J].科学技术与工程,2012,12(36):9828-9832.LI T,YANG Q,FENG W G,et al.Laboratory study of new clean fracturing fluid for coal bed methane and field application[J].Science Technology and Engineering,2012,12(36):9828-9832.
[6]王国强,冯三利,崔会杰.清洁压裂液在煤层气井压裂中的应用[J].天然气工业,2006,26(11):104-107.WANG G Q,FENG S L,CUI H J.Application of clean fracturing fluid in coalbed gas well fracturing[J].Natural Gas Industry,2006,26(11):104-106.
[7]赵辉,戴彩丽,梁利,等.煤层气井用非离子聚丙烯酰胺锆冻胶压裂液优选[J].石油钻探技术,2012,40(1):64-68.ZHAO H,DAI C L,LIANG L,et al.Research on nonionic polyacrylamide zirconium gel fracturing fluids in coalbed methane gas wells[J].Petroleum Drilling Techniques,2012,40(1):64-68.
[8]徐坤,王玲,郭丽梅,等.超低浓度羟丙基瓜胶压裂液在煤层气储层改造中的应用[J].钻采工艺,2016,39(1):111-115.XU K,WANG L,GUO L M,et al.Application of hydroxypropyl guar gun fracturing fluid with superlow concentration in coalbed methane reservoir stimulation[J].Drilling&Production Technology,2016,39(1):111-115.
[9]王黎,陈波,李伟慧.潞安屯留区块煤层气酸化泡沫压裂技术研究[J].石油化工应用,2015,34(4):33-36.WANG L,CHEN B,LI W H.Study on acidified foam fracturing technology of coal-bed methane in Lu’an Tunliu block[J].Petrochemical Industry Application,2015,34(4):33-36.
[10]陈万钢,孙晗森,肖庆华,等.适用于煤层气井的潜在酸压裂液研究[J].科学技术与工程,2015,15(27):132-136.CHEN W G,SUN H S,XIAO Q H,et al.Study on latent acid fracturing fluid applicable to CBM wells[J].Science Technology and Engineering,2015,15(27):132-136.
[11]郭红玉,苏现波,陈俊辉,等.二氧化氯对煤储层的化学增透实验研究[J].煤炭学报,2013,38(4):633-636.GUO H Y,SU X B,CHEN J H,et al.Experimental study on chemical permeability improvement of coal reservoir using chlorine dioxide[J].Journal of China Coal Society,2013,38(4):633-636.
[12]秦志宏,巩涛,李兴顺,等.煤萃取过程的TEM分析与煤嵌布结构模型[J].中国矿业大学学报,2008,37(4):443-449.QIN Z H,GONG T,LI X S,et al.TEM analysis of coal extraction and coal inbuilt state structural model[J].Journal of China University of Mining&Technology,2008,37(4):443-449.
[13]CASTRO M F,LOBODIN V V,RODGERS R P,et al.A molecular model for illinois No.6 argonne premium coal:Moving toward capturing the continuum structure[J].Fuel,2012,95:35-49.
[14]NIEKERK D V,MATHEWS J P.Molecular dynamic simulation of coal solvent interactions in permian-aged South African coals[J].Fuel Processing Technology,2010,92(4):729-734.
[15]张小东,郝宗超,张硕,等.溶剂作用下构造煤纳米级孔隙的差异性变化及机理[J].中国矿业大学学报,2017,46(1):131-136.ZHANG X D,HAO Z C,ZHANG S,et al.Difference of nano-scale pore changes and its control mechanism[J].Journal of China University of Mining&Technology,2017,46(1):131-136.
[16]DYRKAXA G R,BLOOMQUIST C A.Solvent extraction of separated macerals in carbon disulfide/n-methylpyrrolidone[J].Energy&Fuels,2001,15(6):1403-1408.
[17]降文萍.溶剂萃取前后煤吸附甲烷特征对比及机理研究[J].煤炭科学技术,2013,41(3):114-119.JIANG W P.Study on features comparison and mechanism of methane adsorbed by coal before and after solvent extraction[J].Coal Science and Technology,2013,41(3):114-119.
[18]张小东,余坤坤,张硕,等.不同类型酸作用下构造煤表面性的变化机理[J].煤炭转化,2017,40(3):1-7.ZHANG X D,YU K K,ZHANG S,et al.Mechanism for the change in surface property of treated tectonic coal with different acids[J].Coal Conversion,2017,40(3):1-7.
[19]郝宗超,张小东,杨延辉,等.不同溶剂对高阶煤的表面性及孔隙性的改造机理研究[J].煤炭科学技术,2018,46(3):108-114.HAO Z C,ZHANG X D,YANG Y H,et al.Study on reconstruction mechanism of different solvent to surface and porosity of high rank coal[J].Coal Science and Technology,2018,46(3):108-114.
[20]LARSEN J W,PAN C S,SHAWYER S.Effect of demineralization on the macromolecular structure of coals[J].Energy and Fuels,1989,3(5):557-561.
[21]梁虎珍,王传格,曾凡桂,等.应用红外光谱研究脱灰对伊敏褐煤结构的影响[J].燃料化学学报,2014,42(2):129-137.LIANG H Z,WANG C G,ZENG F G,et al.Effect of demineralization on lignite structure from Yinmin coalfield by FT-IR investigation[J].Journal of Fuel Chemistry and Technology,2014,42(2):129-137.
[22]罗晓斌,朱定一,石丽敏.基于接触角法计算固体表面张力的研究进展[J].科学技术与工程,2007,7(19):4997-5004.LUO X B,ZHU D Y,SHI L M.Progress in the calculation of solid surface tension based on contact angle method[J].Science Technology and Engineering,2007,7(19):4997-5004.
[23]朱定一,戴品强,罗晓斌,等.润湿性表征体系及液固界面张力计算的新方法(Ⅰ)[J].科学技术与工程,2007,7(13):3057-3062.ZHU D Y,DAI P Q,LUO X B,et al.Novel characterization of wetting properties and the calculation of liquid-solid interface tension[J].Science Technology and Engineering,2007,7(13):3057-3062.
[24]何杰.煤的表面结构与润湿性[J].选煤技术,2000(5):13-15.HE J.Surface structure and wettability of coal[J].Coal Preparation Technology,2000(5):13-15.
[25]赵振国.吸附作用应用原理[M].北京:化学工业出版社,2005.ZHAO Z G.Principle of adsorption application[M].Beijing:Chemical Industry Press,2005.
[26]孟宪明.煤孔隙结构和煤对气体吸附特性研究[D].青岛:山东科技大学,2007:27-29.MENG X M.Study on the pore structure of coals and characteristics of gases adsorption on coals[D].Qingdao:Shandong University of Science and Technology,2007:27-29.
[27]张硕,张小东,丁哲,等.不同溶剂萃取下高阶煤的化学组成和结构变化[J].煤炭转化,2016,39(3):1-5.ZHANG S,ZHANG X D,DING Z,et al.Chemical composition and structure change of high rank coal extracted by different solvents[J].Coal Conversion,2016,39(3):1-5.
[28]陈润,王治洋,秦勇,等.溶剂极性控制下的煤抽余物吸附甲烷能力研究[J].燃料化学学报,2015,43(10):1153-1157.CHEN R,WANG Z Y,QIN Y,et al.Methane adsorption capacity of extracted coals under control of solvent polarity[J].Journal of Fuel Chemistry and Technology,2015,43(10):1153-1157.
[2]王红岩,李景明,刘洪林,等.中国高煤阶煤层气成藏特征[J].天然气工业,2005,25(12):31-33.WANG H Y,LI J M,LIU H L,et al.The characteristics of high rank coal bed methane reservoir[J].Natural Gas Industry,2005,25(12):31-33.
[3]PENG W,MAO X B,LIN J B,et al.Study of the borehole hydraulic fracturing and the principle of gas seepage in the coal seam[J].Procedia Earth&Planetary Science,2009,1(1):1561-1573.
[4]MIDDLETON R S,CAREY J W,CURRIER R P,et al.Shale gas and non-aqueous fracturing fluids:Opportunities and challenges for supercritical CO2[J].Applied Energy,2015,147(3):500-509.
[5]李亭,杨琦,冯文光,等.煤层气新型清洁压裂液室内研究及现场应用[J].科学技术与工程,2012,12(36):9828-9832.LI T,YANG Q,FENG W G,et al.Laboratory study of new clean fracturing fluid for coal bed methane and field application[J].Science Technology and Engineering,2012,12(36):9828-9832.
[6]王国强,冯三利,崔会杰.清洁压裂液在煤层气井压裂中的应用[J].天然气工业,2006,26(11):104-107.WANG G Q,FENG S L,CUI H J.Application of clean fracturing fluid in coalbed gas well fracturing[J].Natural Gas Industry,2006,26(11):104-106.
[7]赵辉,戴彩丽,梁利,等.煤层气井用非离子聚丙烯酰胺锆冻胶压裂液优选[J].石油钻探技术,2012,40(1):64-68.ZHAO H,DAI C L,LIANG L,et al.Research on nonionic polyacrylamide zirconium gel fracturing fluids in coalbed methane gas wells[J].Petroleum Drilling Techniques,2012,40(1):64-68.
[8]徐坤,王玲,郭丽梅,等.超低浓度羟丙基瓜胶压裂液在煤层气储层改造中的应用[J].钻采工艺,2016,39(1):111-115.XU K,WANG L,GUO L M,et al.Application of hydroxypropyl guar gun fracturing fluid with superlow concentration in coalbed methane reservoir stimulation[J].Drilling&Production Technology,2016,39(1):111-115.
[9]王黎,陈波,李伟慧.潞安屯留区块煤层气酸化泡沫压裂技术研究[J].石油化工应用,2015,34(4):33-36.WANG L,CHEN B,LI W H.Study on acidified foam fracturing technology of coal-bed methane in Lu’an Tunliu block[J].Petrochemical Industry Application,2015,34(4):33-36.
[10]陈万钢,孙晗森,肖庆华,等.适用于煤层气井的潜在酸压裂液研究[J].科学技术与工程,2015,15(27):132-136.CHEN W G,SUN H S,XIAO Q H,et al.Study on latent acid fracturing fluid applicable to CBM wells[J].Science Technology and Engineering,2015,15(27):132-136.
[11]郭红玉,苏现波,陈俊辉,等.二氧化氯对煤储层的化学增透实验研究[J].煤炭学报,2013,38(4):633-636.GUO H Y,SU X B,CHEN J H,et al.Experimental study on chemical permeability improvement of coal reservoir using chlorine dioxide[J].Journal of China Coal Society,2013,38(4):633-636.
[12]秦志宏,巩涛,李兴顺,等.煤萃取过程的TEM分析与煤嵌布结构模型[J].中国矿业大学学报,2008,37(4):443-449.QIN Z H,GONG T,LI X S,et al.TEM analysis of coal extraction and coal inbuilt state structural model[J].Journal of China University of Mining&Technology,2008,37(4):443-449.
[13]CASTRO M F,LOBODIN V V,RODGERS R P,et al.A molecular model for illinois No.6 argonne premium coal:Moving toward capturing the continuum structure[J].Fuel,2012,95:35-49.
[14]NIEKERK D V,MATHEWS J P.Molecular dynamic simulation of coal solvent interactions in permian-aged South African coals[J].Fuel Processing Technology,2010,92(4):729-734.
[15]张小东,郝宗超,张硕,等.溶剂作用下构造煤纳米级孔隙的差异性变化及机理[J].中国矿业大学学报,2017,46(1):131-136.ZHANG X D,HAO Z C,ZHANG S,et al.Difference of nano-scale pore changes and its control mechanism[J].Journal of China University of Mining&Technology,2017,46(1):131-136.
[16]DYRKAXA G R,BLOOMQUIST C A.Solvent extraction of separated macerals in carbon disulfide/n-methylpyrrolidone[J].Energy&Fuels,2001,15(6):1403-1408.
[17]降文萍.溶剂萃取前后煤吸附甲烷特征对比及机理研究[J].煤炭科学技术,2013,41(3):114-119.JIANG W P.Study on features comparison and mechanism of methane adsorbed by coal before and after solvent extraction[J].Coal Science and Technology,2013,41(3):114-119.
[18]张小东,余坤坤,张硕,等.不同类型酸作用下构造煤表面性的变化机理[J].煤炭转化,2017,40(3):1-7.ZHANG X D,YU K K,ZHANG S,et al.Mechanism for the change in surface property of treated tectonic coal with different acids[J].Coal Conversion,2017,40(3):1-7.
[19]郝宗超,张小东,杨延辉,等.不同溶剂对高阶煤的表面性及孔隙性的改造机理研究[J].煤炭科学技术,2018,46(3):108-114.HAO Z C,ZHANG X D,YANG Y H,et al.Study on reconstruction mechanism of different solvent to surface and porosity of high rank coal[J].Coal Science and Technology,2018,46(3):108-114.
[20]LARSEN J W,PAN C S,SHAWYER S.Effect of demineralization on the macromolecular structure of coals[J].Energy and Fuels,1989,3(5):557-561.
[21]梁虎珍,王传格,曾凡桂,等.应用红外光谱研究脱灰对伊敏褐煤结构的影响[J].燃料化学学报,2014,42(2):129-137.LIANG H Z,WANG C G,ZENG F G,et al.Effect of demineralization on lignite structure from Yinmin coalfield by FT-IR investigation[J].Journal of Fuel Chemistry and Technology,2014,42(2):129-137.
[22]罗晓斌,朱定一,石丽敏.基于接触角法计算固体表面张力的研究进展[J].科学技术与工程,2007,7(19):4997-5004.LUO X B,ZHU D Y,SHI L M.Progress in the calculation of solid surface tension based on contact angle method[J].Science Technology and Engineering,2007,7(19):4997-5004.
[23]朱定一,戴品强,罗晓斌,等.润湿性表征体系及液固界面张力计算的新方法(Ⅰ)[J].科学技术与工程,2007,7(13):3057-3062.ZHU D Y,DAI P Q,LUO X B,et al.Novel characterization of wetting properties and the calculation of liquid-solid interface tension[J].Science Technology and Engineering,2007,7(13):3057-3062.
[24]何杰.煤的表面结构与润湿性[J].选煤技术,2000(5):13-15.HE J.Surface structure and wettability of coal[J].Coal Preparation Technology,2000(5):13-15.
[25]赵振国.吸附作用应用原理[M].北京:化学工业出版社,2005.ZHAO Z G.Principle of adsorption application[M].Beijing:Chemical Industry Press,2005.
[26]孟宪明.煤孔隙结构和煤对气体吸附特性研究[D].青岛:山东科技大学,2007:27-29.MENG X M.Study on the pore structure of coals and characteristics of gases adsorption on coals[D].Qingdao:Shandong University of Science and Technology,2007:27-29.
[27]张硕,张小东,丁哲,等.不同溶剂萃取下高阶煤的化学组成和结构变化[J].煤炭转化,2016,39(3):1-5.ZHANG S,ZHANG X D,DING Z,et al.Chemical composition and structure change of high rank coal extracted by different solvents[J].Coal Conversion,2016,39(3):1-5.
[28]陈润,王治洋,秦勇,等.溶剂极性控制下的煤抽余物吸附甲烷能力研究[J].燃料化学学报,2015,43(10):1153-1157.CHEN R,WANG Z Y,QIN Y,et al.Methane adsorption capacity of extracted coals under control of solvent polarity[J].Journal of Fuel Chemistry and Technology,2015,43(10):1153-1157.