颗粒粒径对低温氮吸附实验的影响——以五峰组—龙马溪组海相含气页岩为例
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摘要
为了探索页岩颗粒的粒径对低温氮吸附实验的影响和其机理,以渝东南彭水地区五峰组—龙马溪组为例,优选3块TOC和矿物组成差异明显的高—过成熟海相页岩样品,分别开展8组不同粒度(范围为80～4 750μm)的低温氮气吸附实验(LTNA),进而探索颗粒粒径对实验结果的影响,并从孔隙类型和连通性角度揭示了影响机理,提出五峰组—龙马溪组海相页岩LNTA实验建议粒径为180～250μm.研究结果表明:LTNA实验测量的页岩总孔体积明显受粒径的影响,随粒径减小,测量值呈现先逐渐增加、再减小、然后再增加的规律,而对比表面积影响较小.微孔和较小介孔(<10nm)以有机孔和黏土矿物晶内-晶间孔为主,具有较长的连续渗流路径长度,在较大粒度区间内(>180μm),适当减小粒度能提高该类孔隙的测量值,但随着继续粉碎(<180μm),这类孔隙会遭到破坏;而宏孔和较大介孔(>10nm)的渗流路径长度较短,需要样品粉碎至一定程度(180～250μm),才能与颗粒外表面有效沟通,其测量值随粒度减小而明显增大,但粉碎程度过高会产生新的微裂缝,导致实验测量值明显高于压汞法和扫描电镜结果.
To explore the effect of particle size on low temperature nitrogen adsorption(LTNA)experiment and its mechanism,this study selected three high-to post-mature marine shale samples,with various TOC and mineral compositions,from the Wufeng and Longmaxi formations in Pengshui area of southeast Chongqing.Shale samples,with various particle sizes(ranging from 80 to 4 750μm),were subjected to eight sets of LTNA experiments,and then the effect of particle size on the experimental results and its mechanism from perspectives of pore type and connectivity was revealed.This study suggested that a particle size of 180—250μm should be used in the LNTA experiment for the Wufeng and Longmaxi marine shales.The results show that the total pore volume of shale derived from LTNA is obviously affected by particle size.With the decrease of particle size,the measured value first increases gradually,then decreases,and rises again.However,the effect of particle size on specific surface area is relatively insignificant.Micropores and smaller mesopores(<10 nm)are mainly composed of organic matter pores and intra-/inter-crystalline pores within clay minerals,with a longer continuous percolation path.These pores can be better characterized with a declining particle size at a greater particle size interval(>180μm),while these pores may be destroyed with a continued pulverization(<180μm).Macropores and larger mesopores(>10 nm)correspond to a shorter percolation path,which can effectively communicate with the external surface of particle when the sample is pulverized to 180—250μm.The measured value of these pores increases significantly with the decreasing particle size.Nevertheless,new micro-fractures will be generated,when the sample is smashed too small,resulting in that the results derived from LTNA experiments are obviously greater than those measured by mercury intrusion porosimetry and scanning electron microscopy.
To explore the effect of particle size on low temperature nitrogen adsorption(LTNA)experiment and its mechanism,this study selected three high-to post-mature marine shale samples,with various TOC and mineral compositions,from the Wufeng and Longmaxi formations in Pengshui area of southeast Chongqing.Shale samples,with various particle sizes(ranging from 80 to 4 750μm),were subjected to eight sets of LTNA experiments,and then the effect of particle size on the experimental results and its mechanism from perspectives of pore type and connectivity was revealed.This study suggested that a particle size of 180—250μm should be used in the LNTA experiment for the Wufeng and Longmaxi marine shales.The results show that the total pore volume of shale derived from LTNA is obviously affected by particle size.With the decrease of particle size,the measured value first increases gradually,then decreases,and rises again.However,the effect of particle size on specific surface area is relatively insignificant.Micropores and smaller mesopores(<10 nm)are mainly composed of organic matter pores and intra-/inter-crystalline pores within clay minerals,with a longer continuous percolation path.These pores can be better characterized with a declining particle size at a greater particle size interval(>180μm),while these pores may be destroyed with a continued pulverization(<180μm).Macropores and larger mesopores(>10 nm)correspond to a shorter percolation path,which can effectively communicate with the external surface of particle when the sample is pulverized to 180—250μm.The measured value of these pores increases significantly with the decreasing particle size.Nevertheless,new micro-fractures will be generated,when the sample is smashed too small,resulting in that the results derived from LTNA experiments are obviously greater than those measured by mercury intrusion porosimetry and scanning electron microscopy.
引文
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[4]LOUCKS R G,REED R M,RUPPEL S C,et al.Morphology,genesis,and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett shale[J].Journal of Sedimentary Research,2009,79(12):848-861.
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[7]ZHOU S,YAN G,XUE H,et al.2Dand 3Dnanopore characterization of gas shale in Longmaxi formation based on FIB-SEM[J].Marine&Petroleum Geology,2016,73:174-180.
[8]HUANG X,ZHAO Y P.Characterization of pore structure,gas adsorption,and spontaneous imbibition in gas shale reservoirs[J].Journal of Petroleum Science&Engineering,2017,159:197-204.
[9]CHEN F W,DING X,LU S F,et al.The Pore characterization of the Lower Silurian Longmaxi shale in the southeast Chongqing,China using FE-SEM,LTNAand MIP methods[J].Journal of Nanoscience&Nanotechnology,2017,17(9):6482-6488.
[10]GREGG S J,SING K S W.Adsorption,surface area,and porosity[M].London:Academic Press,1982:220-221.
[11]杨峰,宁正福,胡昌蓬,等.页岩储层微观孔隙结构特征[J].石油学报,2013,34(2):301-311.YANG Feng,NING Zhengfu,HU Changpeng,et al.Micropore structure characteristics of shale reservoir[J].Acta Petrolei Sinica,2013,34(2):301-311.
[12]HAN H,CAO Y,CHEN S,et al.Influence of particle size on gas-adsorption experiments of shales:An example from a Longmaxi shale sample from the Sichuan basin,China[J].Fuel,2016,186:750-757.
[13]MASTALERZ M,HAMPTON L B,DROBNIAKA,et al.Significance of analytical particle size in low-pressure N2,and CO2,adsorption of coal and shale[J].International Journal of Coal Geology,2017,178:122-131.
[14]FURMANN A,MASTALERZ M,BISH D,et al.Porosity and pore size distribution in mudrocks from the Belle Fourche and Second White Specks formations in Alberta,Canada[J].Aapg Bulletin,2016,100(8):1265-1288.
[15]SWANSON S M,MASTALERZ M D,ENGLE MA,et al.Pore characteristics of Wilcox Group Coal,U.S.gulf coast region:Implications for the occurrence of coalbed gas[J].International Journal of Coal Geology,2015,139(1):80-94.
[16]CHALMERS G R,BUSTIN R M,POWER I M.Characterization of gas shale pore systems by porosimetry,pycnometry,surface area,and field emission scanning electron microscopy/transmission electron microscopy image analyses:examples from the Barnett,Woodford,Haynesville,Marcellus,and Doig unit[J].Aapg Bulletin,2012,96(6):1099-1119.
[17]LI J,YIN J,ZHANG Y,et al.A comparison of experimental methods for describing shale pore features:a case study in the Bohai Bay basin of eastern China[J].International Journal of Coal Geology,2015,152:39-49.
[18]WANG M,XUE H,TIAN S,et al.Fractal characteristics of Upper Cretaceous lacustrine shale from the Songliao basin,NE China[J].Marine&Petroleum Geology,2015,67:144-153.
[19]MASTALERZ M,SCHIMMELMANN A,DROB-NIAK A,et al.Porosity of Devonian and Mississippian New Albany shale across a maturation gradient:insights from organic petrology,gas adsorption,and mercury intrusion[J].Aapg Bulletin,2013,97(10):1621-1643.
[20]CAO T,SONG Z,WANG S,et al.Characterizing the pore structure in the Silurian and Permian shales of the Sichuan basin,China[J].Marine&Petroleum Geology,2015,61:140-150.
[21]王秀平,牟传龙,葛详英,等.川南及邻区龙马溪组黑色岩系矿物组分特征及评价[J].石油学报,2015,36(2):150-162.WANG Xiuping,MU Chuanlong,GE Xiangying,et al.Mineralogical characteristics and evaluation of black rock of Longmaxi formation in southern Sichuan and its periphery[J].Acta Petrolei Sinica,2015,36(2):150-162.
[22]严继民,张启元.吸附法研究固体表面与孔结构[J].石油化工,1977(6):14-26.YAN Jimin,ZHANG Qiyuan.Study of solid surface and pore structure by adsorption method[J].Petrochemical Industry,1977:14-26.
[23]SING K S W.Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity[J].Pure&Applied Chemistry,1985,57(4):603-619.
[24]BRUNAUER S,EMMETT P H,TELLER E.Adsorption of gases in multimolecular layers[J].Journal of the American Chemical Society,1938,60(2):309-319.
[25]BARRETT E P,JOYNER L G,HALENDA P P.The determination of pore volume and area distributions in porous substances I computations from nitrogen isotherms[J].Journal of the American Chemical Society,1951,73(1):373-380.
[26]DR M T.Physical adsorption characterization of nanoporous materials[J].Chemie Ingenieur Technik,2010,82(7):1059-1073.
[27]THOMMES M,KANEKO K,NEIMARK A V,et al.Physisorption of gases,with special reference to the evaluation of surface area and pore size distribution(IUPAC Technical Report)[J].Chemistry International,2015,87(9/10):1051-1069.
[28]杨峰,宁正福,张世栋,等.基于氮气吸附实验的页岩孔隙结构表征[J].天然气工业,2013,33(4):135-140.YANG Feng,NING Zhengfu,ZHANG Shidong,et al.Characterization of shale pore structure based on nitrogen adsorption[J].Natural Gas Industry,2013,33(4):135-140.
[29]康毅力,陈益滨,李相臣,等.页岩粒径对甲烷吸附性能影响[J].天然气地球科学,2017,28(2):272-279.KANG Yili,CHEN Yibin,LI Xiangchen,et al.Effect of shale particle size on adsorption performance of methane[J].Natural Gas Geoscience,2017,28(2):272-279.
[30]李贤庆,王哲,郭曼,等.黔北地区下古生界页岩气储层孔隙结构特征[J].中国矿业大学学报,2016,45(6):1172-1183.LI Xianqing,WANG Zhe,GUO Man,et al.Pore structure characteristics of the Lower Paleozoic formation shale gas reservoir in northern Guizhou[J].Journal of China University of Mining&Technology,2016,45(6):1172-1183.
[31]LOUCKS R G,REED R M,RUPPEL S C,et al.Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores[J].Aapg Bulletin,2012,96(6):1071-1098.
[32]DESBOIS G,URAI J L,KUKLA P A,et al.Highresolution 3Dfabric and porosity model in a tight gas sandstonereservoir:A new approach to investigate microstructures from mm-to nm-scale combining argon beam cross-sectioning and SEM imaging[J].Journal of Petroleum Science&Engineering,2011,78(2):243-257.
[33]ZAPATA Y,SAKHAEE-POUR A.Modeling adsorption-desorption hysteresis in shales:A cyclic pore model[J].Fuel,2016,181:557-565.
[34]JULLIEN M,RAYNAL J,KOHLER,et al.Physicochemical reactivity in clay-rich materials:Tools for safety assessment[J].Oil&Gas Science&Technology,2005,60(60):107-120.
[35]JIANG C B.Pore structure characterization of shale at the micro-and macro-scale[D].Austin:The University of Texas,2016:53-81.
[36]EMMANUEL S,ELIYAHU M,DAY-STIRRAT RJ,et al.Impact of thermal maturation on nano-scale elastic properties of organic matter in shales[J].Marine&Petroleum Geology,2016,70:175-184.
[2]张金川,聂海宽,薛会,等.中国天然气勘探的2个新领域:根缘气和页岩气[C]//中国西部复杂油气藏地质与勘探技术研讨会论文集.长沙:中南大学学报(自然科学版),2006:12-16.ZHANG Jinchuan,NIE Haikuan,XUE Hui,et al.Two new fields of natural gas exploration in China:root gas and shale gas[C]//Proceedings of the Symposium on the Geological and Exploration Technology of the Complex Oil and Gas Reservoir in western China.Changsha:Journal of Central South University(Science and Technology),2006:12-16.
[3]武景淑,于炳松,李玉喜.渝东南渝页1井页岩气吸附能力及其主控因素[J].西南石油大学学报(自然科学版),2012,34(4):40-48.WU Jingshu,YU Bingsong,LI Yuxi.Shale gas adsorption capacity and its main control factors of well Yuye 1in southeast Chongqing[J].Journal of Southwest Petroleum University(Natural Science Edition),2012,34(4):40-48.
[4]LOUCKS R G,REED R M,RUPPEL S C,et al.Morphology,genesis,and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett shale[J].Journal of Sedimentary Research,2009,79(12):848-861.
[5]ELAMATI M.Shale gas rock characterization and 3Dsubmicron pore network reconstruction[D].Missouri:Missouri University of Science and Technology,2011:27-44.
[6]钟太贤.中国南方海相页岩孔隙结构特征[J].天然气工业,2012,32(9):1-4.ZHONG Taixian.Characteristics of pore structure of marine shale in southern China[J].Natural Gas Industry,2012,32(9):1-4.
[7]ZHOU S,YAN G,XUE H,et al.2Dand 3Dnanopore characterization of gas shale in Longmaxi formation based on FIB-SEM[J].Marine&Petroleum Geology,2016,73:174-180.
[8]HUANG X,ZHAO Y P.Characterization of pore structure,gas adsorption,and spontaneous imbibition in gas shale reservoirs[J].Journal of Petroleum Science&Engineering,2017,159:197-204.
[9]CHEN F W,DING X,LU S F,et al.The Pore characterization of the Lower Silurian Longmaxi shale in the southeast Chongqing,China using FE-SEM,LTNAand MIP methods[J].Journal of Nanoscience&Nanotechnology,2017,17(9):6482-6488.
[10]GREGG S J,SING K S W.Adsorption,surface area,and porosity[M].London:Academic Press,1982:220-221.
[11]杨峰,宁正福,胡昌蓬,等.页岩储层微观孔隙结构特征[J].石油学报,2013,34(2):301-311.YANG Feng,NING Zhengfu,HU Changpeng,et al.Micropore structure characteristics of shale reservoir[J].Acta Petrolei Sinica,2013,34(2):301-311.
[12]HAN H,CAO Y,CHEN S,et al.Influence of particle size on gas-adsorption experiments of shales:An example from a Longmaxi shale sample from the Sichuan basin,China[J].Fuel,2016,186:750-757.
[13]MASTALERZ M,HAMPTON L B,DROBNIAKA,et al.Significance of analytical particle size in low-pressure N2,and CO2,adsorption of coal and shale[J].International Journal of Coal Geology,2017,178:122-131.
[14]FURMANN A,MASTALERZ M,BISH D,et al.Porosity and pore size distribution in mudrocks from the Belle Fourche and Second White Specks formations in Alberta,Canada[J].Aapg Bulletin,2016,100(8):1265-1288.
[15]SWANSON S M,MASTALERZ M D,ENGLE MA,et al.Pore characteristics of Wilcox Group Coal,U.S.gulf coast region:Implications for the occurrence of coalbed gas[J].International Journal of Coal Geology,2015,139(1):80-94.
[16]CHALMERS G R,BUSTIN R M,POWER I M.Characterization of gas shale pore systems by porosimetry,pycnometry,surface area,and field emission scanning electron microscopy/transmission electron microscopy image analyses:examples from the Barnett,Woodford,Haynesville,Marcellus,and Doig unit[J].Aapg Bulletin,2012,96(6):1099-1119.
[17]LI J,YIN J,ZHANG Y,et al.A comparison of experimental methods for describing shale pore features:a case study in the Bohai Bay basin of eastern China[J].International Journal of Coal Geology,2015,152:39-49.
[18]WANG M,XUE H,TIAN S,et al.Fractal characteristics of Upper Cretaceous lacustrine shale from the Songliao basin,NE China[J].Marine&Petroleum Geology,2015,67:144-153.
[19]MASTALERZ M,SCHIMMELMANN A,DROB-NIAK A,et al.Porosity of Devonian and Mississippian New Albany shale across a maturation gradient:insights from organic petrology,gas adsorption,and mercury intrusion[J].Aapg Bulletin,2013,97(10):1621-1643.
[20]CAO T,SONG Z,WANG S,et al.Characterizing the pore structure in the Silurian and Permian shales of the Sichuan basin,China[J].Marine&Petroleum Geology,2015,61:140-150.
[21]王秀平,牟传龙,葛详英,等.川南及邻区龙马溪组黑色岩系矿物组分特征及评价[J].石油学报,2015,36(2):150-162.WANG Xiuping,MU Chuanlong,GE Xiangying,et al.Mineralogical characteristics and evaluation of black rock of Longmaxi formation in southern Sichuan and its periphery[J].Acta Petrolei Sinica,2015,36(2):150-162.
[22]严继民,张启元.吸附法研究固体表面与孔结构[J].石油化工,1977(6):14-26.YAN Jimin,ZHANG Qiyuan.Study of solid surface and pore structure by adsorption method[J].Petrochemical Industry,1977:14-26.
[23]SING K S W.Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity[J].Pure&Applied Chemistry,1985,57(4):603-619.
[24]BRUNAUER S,EMMETT P H,TELLER E.Adsorption of gases in multimolecular layers[J].Journal of the American Chemical Society,1938,60(2):309-319.
[25]BARRETT E P,JOYNER L G,HALENDA P P.The determination of pore volume and area distributions in porous substances I computations from nitrogen isotherms[J].Journal of the American Chemical Society,1951,73(1):373-380.
[26]DR M T.Physical adsorption characterization of nanoporous materials[J].Chemie Ingenieur Technik,2010,82(7):1059-1073.
[27]THOMMES M,KANEKO K,NEIMARK A V,et al.Physisorption of gases,with special reference to the evaluation of surface area and pore size distribution(IUPAC Technical Report)[J].Chemistry International,2015,87(9/10):1051-1069.
[28]杨峰,宁正福,张世栋,等.基于氮气吸附实验的页岩孔隙结构表征[J].天然气工业,2013,33(4):135-140.YANG Feng,NING Zhengfu,ZHANG Shidong,et al.Characterization of shale pore structure based on nitrogen adsorption[J].Natural Gas Industry,2013,33(4):135-140.
[29]康毅力,陈益滨,李相臣,等.页岩粒径对甲烷吸附性能影响[J].天然气地球科学,2017,28(2):272-279.KANG Yili,CHEN Yibin,LI Xiangchen,et al.Effect of shale particle size on adsorption performance of methane[J].Natural Gas Geoscience,2017,28(2):272-279.
[30]李贤庆,王哲,郭曼,等.黔北地区下古生界页岩气储层孔隙结构特征[J].中国矿业大学学报,2016,45(6):1172-1183.LI Xianqing,WANG Zhe,GUO Man,et al.Pore structure characteristics of the Lower Paleozoic formation shale gas reservoir in northern Guizhou[J].Journal of China University of Mining&Technology,2016,45(6):1172-1183.
[31]LOUCKS R G,REED R M,RUPPEL S C,et al.Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores[J].Aapg Bulletin,2012,96(6):1071-1098.
[32]DESBOIS G,URAI J L,KUKLA P A,et al.Highresolution 3Dfabric and porosity model in a tight gas sandstonereservoir:A new approach to investigate microstructures from mm-to nm-scale combining argon beam cross-sectioning and SEM imaging[J].Journal of Petroleum Science&Engineering,2011,78(2):243-257.
[33]ZAPATA Y,SAKHAEE-POUR A.Modeling adsorption-desorption hysteresis in shales:A cyclic pore model[J].Fuel,2016,181:557-565.
[34]JULLIEN M,RAYNAL J,KOHLER,et al.Physicochemical reactivity in clay-rich materials:Tools for safety assessment[J].Oil&Gas Science&Technology,2005,60(60):107-120.
[35]JIANG C B.Pore structure characterization of shale at the micro-and macro-scale[D].Austin:The University of Texas,2016:53-81.
[36]EMMANUEL S,ELIYAHU M,DAY-STIRRAT RJ,et al.Impact of thermal maturation on nano-scale elastic properties of organic matter in shales[J].Marine&Petroleum Geology,2016,70:175-184.