基于低场核磁共振的煤润湿性分析
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摘要
煤润湿性在煤化工、煤矿安全生产及煤层气开发利用中有重要意义。目前煤的润湿性测定方法过程繁琐、操作困难、现场实用性差、测量结果可对比性差,不能快速有效地应用于煤层气储层的润湿性评价研究。基于系列低场核磁共振(LFNMR)实验,探讨了LFNMR应用于煤润湿性研究的可行性与研究方法。研究发现,LFNMR可应用于识别煤粉中不同状态水分:对于强水湿性煤粉,其T2弛豫谱仅存在吸附态水峰与颗粒间水峰,而弱水湿性煤粉则存在吸附态水峰、颗粒间水峰和自由态水峰3个峰值;煤的水湿性越强,其颗粒间水峰和自由态水峰弛豫时间越短,并随着润湿时间的增加弛豫逐渐变快。当水对煤的润湿达到稳定状态时,煤样的自由态水峰和颗粒间水峰的加权平均值与型煤接触角法测得的接触角呈相关性较好的对数关系。该对数关系可应用于煤水润湿性的定量、半定量评价,这为采用该方法进一步研究煤储层的气、水相互作用提供了理论基础。
The research on coal wettability is significant in coal chemical industry,safety of coal mining,and coalbed methane(CBM) production. The conventional methods for coal wettability determination are difficult to be performed and unsuitable for an in-situ measurement,which make it difficult to be used as in-situ analysis method for determining wettability of CBM reservoirs. Based on a series of low-field nuclear magnetic resonance(LFNMR) experiments,this paper discussed the practicality of the application of LFNMR in evaluation of the wettability of CBM reservoirs. It was found that moistures in the coals have different phases including the free water,interparticle capillary confined water,and adsorption water that can be distinguished by the water transverse relaxation time(T2) spectra in a LFNMR measurement. For the hydrophilic powdered coal,there are adsorbed water and interparticle water that correspond to two distinct peaks in the T2 spectra. For hydrophobic powdered coal,there exist adsorbed,interparticle and free waters,corresponding to three distinct peaks in the T2 spectra. The stronger the hydrophilicity is,the faster the relaxation time of capillary water and free water is.In an equilibrium system of the coal-water wettability,the geometric mean value of T2 for free and capillary wa-ters is found to be logarithmically correlated with the contact angle between coal and water that is determined from a conventional method. We suggest that the low-field NMR is quantifiably or semi-quantifiably applicable for estimation of coal wettability,which provides an important theoretical foundation for evaluating the water-gas interactions in a CBM reservoir by using LFNMR.
The research on coal wettability is significant in coal chemical industry,safety of coal mining,and coalbed methane(CBM) production. The conventional methods for coal wettability determination are difficult to be performed and unsuitable for an in-situ measurement,which make it difficult to be used as in-situ analysis method for determining wettability of CBM reservoirs. Based on a series of low-field nuclear magnetic resonance(LFNMR) experiments,this paper discussed the practicality of the application of LFNMR in evaluation of the wettability of CBM reservoirs. It was found that moistures in the coals have different phases including the free water,interparticle capillary confined water,and adsorption water that can be distinguished by the water transverse relaxation time(T2) spectra in a LFNMR measurement. For the hydrophilic powdered coal,there are adsorbed water and interparticle water that correspond to two distinct peaks in the T2 spectra. For hydrophobic powdered coal,there exist adsorbed,interparticle and free waters,corresponding to three distinct peaks in the T2 spectra. The stronger the hydrophilicity is,the faster the relaxation time of capillary water and free water is.In an equilibrium system of the coal-water wettability,the geometric mean value of T2 for free and capillary wa-ters is found to be logarithmically correlated with the contact angle between coal and water that is determined from a conventional method. We suggest that the low-field NMR is quantifiably or semi-quantifiably applicable for estimation of coal wettability,which provides an important theoretical foundation for evaluating the water-gas interactions in a CBM reservoir by using LFNMR.
引文
[1]Guo R,Kantzas A.Assessing the water uptake of Alberta coal and the impact of CO2injection with low-field NMR[J].Canadian Petroleum Technology,2009,48(7):40-46.
[2]Shojai K N,Rudolph E S,Wolf K H,et al.Wettability determination by contact angle measurements:hvb B coal-water system with injection of synthetic flue gas and CO2[J].Journal of Colloid and Interface Science,2011,364(1):237-247.
[3]Donaldson E C,Thomas R D,Lorenz P B.Wettability determination and its effect on recovery efficiency[J].Society of Petroleum Engineers Journal,1969,9(1):13-20.
[4]解兴智,傅贵.煤润湿性测量方法的探讨[J].煤炭科学技术,2004,32(2):65-68.
[5]牛蓉,卢建军,李凡,等.煤的表面处理及润湿性研究[J].煤炭转化,2001,24(1):44-49.
[6]傅贵,秦凤华,阎保金.我国部分矿区煤的水润湿性研究[J].阜新矿业学院学报:自然科学版,1997,16(6):666-669.
[7]徐红军,胡法龙.核磁共振T2判断EDWARDS灰岩的润湿性[J].国外测井术,2009(1):39-42.
[8]Johannesen E B,Riskedal H,Tipura L.Wettability characterization by NMR T2measurements in Edwards limestone rock[M]//The Society of Core Analysts.International Symposium of the Society of Core Analysts.Calgary:The Society of Core Analysts,2007:1-12.
[9]Bortolotii V,Macini P,Falan S.Combined spatially resolved and non-resolved 1H-NMR relaxation analysis to assess and monitor wettability reversal in carbonate rocks[M]//Society of Petroleum Engineers.International Petroleum Technology Conference.Texas:Society of Petroleum Engineers,2009:1-8.
[10]王为民.核磁共振岩石物理研究及其在石油工业中的应用[D].北京:中国科学院武汉物理与数学研究所,2001:29-115.
[11]Manalo F,Kantzas A.Soil wettability as determined from using low-field nuclear magnetic resonance[J].Environmental Science Technology,2003,37(12):2701-2706.
[12]Odusina E O,Sondergeld C H,Rai C S.NMR study of shale wettability[M]//Society of Petroleum Engineers.The Canadian Unconventional Resources Conference.Texas:Society of Petroleum Engineers,2011:1-9.
[13]George C,肖立志.核磁共振测井原理与应用[M].孟繁莹,译.北京:石油工业出版社,2007:1-100.
[14]刘卫,邢立.核磁共振录井[M].北京:石油工业出版社,2011:1-100.
[15]Yao Y B,Liu D M,Che Y,et al.Petrophysical characterization of coals by low-field nuclear magnetic resonance(NMR)[J].Fuel,2010,89(7):1371-1380.
[16]姚艳斌,刘大锰,蔡益栋,等.基于NMR和X-CT的煤的孔隙裂隙精细定量表征[J].中国科学:D辑,2010,40(11):1598-1607.
[17]Kleinberg R L,Vinegar H J.NMR properties of reservoir fluids[J].The Log Analyst,1996,37(6):20-32.
[18]Guo R.Transport phenomena in coalbeds[D].Calgary:University of Calgary,2008:246-329.
[19]王彩云,梅国民,杨建国.煤的润湿性测量中煤样制备方法的探讨[J].洁净煤技术,2005,11(2):15-17.
[20]董平,单忠健,李哲.超细煤粉表面润湿性的研究[J].煤炭学报,2004,29(3):346-349.
[21]傅贵,张英华,邹得志.煤与纯水间平衡接触角的测量与分析[J].煤炭转化,1997,20(4):60-62.
[22]付万军,解兴智,梁春豪.煤水平衡接触角的影响因素研究[J].煤炭科学技术,2002,30(2):58-59.
[23]Yao Y B,Liu D M,Xie S B.Quantitative characterization of methane adsorption on coal using a low-field NMR relaxation method[J].International Journal of Coal Geology,2014,131(1):32-40.
[24]胡宝林,杨起,刘大锰,等.新疆地区侏罗系中低变质煤储层吸附特征及煤层气资源前景[J].现代地质,2002,16(1):77-82.
[25]崔思华,刘洪林,王勃,等.准噶尔盆地低煤级煤层气成藏地质特征[J].现代地质,2007,21(4):719-724.
[26]何杰.煤的表面结构与润湿性[J].选煤技术,2000(5):13-15.
[27]刘大锰,姚艳斌,蔡益栋,等.华北石炭-二叠系煤的孔渗特征及主控因素[J].现代地质,2010,24(6):1198-1203.
[28]刘贝,黄文辉,敖卫华,等.沁水盆地南部煤中矿物赋存特征及其对煤储层物性的影响[J].现代地质,2014,28(3):645-652.
[29]Willem-Jan P,Saikat M,Jonannes B.Capillary pressure and wettability behavior of CO2sequestration in coal at elevated pressures[J].SPE Journal,2008,13(4):455-464.
[30]黄文辉,敖卫华,翁成敏,等.鄂尔多斯盆地侏罗纪煤的煤岩特征及成因分析[J].现代地质,2010,24(6):1187-1197.
[2]Shojai K N,Rudolph E S,Wolf K H,et al.Wettability determination by contact angle measurements:hvb B coal-water system with injection of synthetic flue gas and CO2[J].Journal of Colloid and Interface Science,2011,364(1):237-247.
[3]Donaldson E C,Thomas R D,Lorenz P B.Wettability determination and its effect on recovery efficiency[J].Society of Petroleum Engineers Journal,1969,9(1):13-20.
[4]解兴智,傅贵.煤润湿性测量方法的探讨[J].煤炭科学技术,2004,32(2):65-68.
[5]牛蓉,卢建军,李凡,等.煤的表面处理及润湿性研究[J].煤炭转化,2001,24(1):44-49.
[6]傅贵,秦凤华,阎保金.我国部分矿区煤的水润湿性研究[J].阜新矿业学院学报:自然科学版,1997,16(6):666-669.
[7]徐红军,胡法龙.核磁共振T2判断EDWARDS灰岩的润湿性[J].国外测井术,2009(1):39-42.
[8]Johannesen E B,Riskedal H,Tipura L.Wettability characterization by NMR T2measurements in Edwards limestone rock[M]//The Society of Core Analysts.International Symposium of the Society of Core Analysts.Calgary:The Society of Core Analysts,2007:1-12.
[9]Bortolotii V,Macini P,Falan S.Combined spatially resolved and non-resolved 1H-NMR relaxation analysis to assess and monitor wettability reversal in carbonate rocks[M]//Society of Petroleum Engineers.International Petroleum Technology Conference.Texas:Society of Petroleum Engineers,2009:1-8.
[10]王为民.核磁共振岩石物理研究及其在石油工业中的应用[D].北京:中国科学院武汉物理与数学研究所,2001:29-115.
[11]Manalo F,Kantzas A.Soil wettability as determined from using low-field nuclear magnetic resonance[J].Environmental Science Technology,2003,37(12):2701-2706.
[12]Odusina E O,Sondergeld C H,Rai C S.NMR study of shale wettability[M]//Society of Petroleum Engineers.The Canadian Unconventional Resources Conference.Texas:Society of Petroleum Engineers,2011:1-9.
[13]George C,肖立志.核磁共振测井原理与应用[M].孟繁莹,译.北京:石油工业出版社,2007:1-100.
[14]刘卫,邢立.核磁共振录井[M].北京:石油工业出版社,2011:1-100.
[15]Yao Y B,Liu D M,Che Y,et al.Petrophysical characterization of coals by low-field nuclear magnetic resonance(NMR)[J].Fuel,2010,89(7):1371-1380.
[16]姚艳斌,刘大锰,蔡益栋,等.基于NMR和X-CT的煤的孔隙裂隙精细定量表征[J].中国科学:D辑,2010,40(11):1598-1607.
[17]Kleinberg R L,Vinegar H J.NMR properties of reservoir fluids[J].The Log Analyst,1996,37(6):20-32.
[18]Guo R.Transport phenomena in coalbeds[D].Calgary:University of Calgary,2008:246-329.
[19]王彩云,梅国民,杨建国.煤的润湿性测量中煤样制备方法的探讨[J].洁净煤技术,2005,11(2):15-17.
[20]董平,单忠健,李哲.超细煤粉表面润湿性的研究[J].煤炭学报,2004,29(3):346-349.
[21]傅贵,张英华,邹得志.煤与纯水间平衡接触角的测量与分析[J].煤炭转化,1997,20(4):60-62.
[22]付万军,解兴智,梁春豪.煤水平衡接触角的影响因素研究[J].煤炭科学技术,2002,30(2):58-59.
[23]Yao Y B,Liu D M,Xie S B.Quantitative characterization of methane adsorption on coal using a low-field NMR relaxation method[J].International Journal of Coal Geology,2014,131(1):32-40.
[24]胡宝林,杨起,刘大锰,等.新疆地区侏罗系中低变质煤储层吸附特征及煤层气资源前景[J].现代地质,2002,16(1):77-82.
[25]崔思华,刘洪林,王勃,等.准噶尔盆地低煤级煤层气成藏地质特征[J].现代地质,2007,21(4):719-724.
[26]何杰.煤的表面结构与润湿性[J].选煤技术,2000(5):13-15.
[27]刘大锰,姚艳斌,蔡益栋,等.华北石炭-二叠系煤的孔渗特征及主控因素[J].现代地质,2010,24(6):1198-1203.
[28]刘贝,黄文辉,敖卫华,等.沁水盆地南部煤中矿物赋存特征及其对煤储层物性的影响[J].现代地质,2014,28(3):645-652.
[29]Willem-Jan P,Saikat M,Jonannes B.Capillary pressure and wettability behavior of CO2sequestration in coal at elevated pressures[J].SPE Journal,2008,13(4):455-464.
[30]黄文辉,敖卫华,翁成敏,等.鄂尔多斯盆地侏罗纪煤的煤岩特征及成因分析[J].现代地质,2010,24(6):1187-1197.