基于CT扫描的煤岩孔隙结构全孔径表征

doi:10.3969/j.issn.1006-6535.2024.04.009

摘要/Abstract

摘要： 为探究深层、超深层煤岩孔隙结构,在鄂尔多斯盆地DJ区块本溪组X号煤岩采集了12块样品,基于数字岩心CT扫描三维重构技术,联合高压压汞、液氮吸附、二氧化碳吸附测试,应用多实验拼接方法,表征了X号煤岩孔隙的全孔径分布特征,并对比分析深层及中浅层煤岩的微孔、介孔、大孔的分布差异及其对吸附作用、渗透率的影响。研究表明:煤岩储层的储集空间以微孔及大孔为主,介孔发育较少;深层X号煤岩微孔平均占比为44.1%,大孔平均占比为53.9%,中浅层X号煤岩中微孔平均占比为34.8%,大孔平均占比为64.1%;深层煤岩中起吸附作用的纳米孔更发育,但在中浅层煤岩中微米级裂缝发育程度优于深层煤;通过全孔径分布特征分析认为,中浅层X号煤岩大孔孔容占比更高,渗透率比深层X煤岩高出1个数量级,而深层X号煤岩微孔孔容占比更高,吸附性更强。该研究通过全孔径定量表征,明确储层各级孔隙分布特征,为煤层气赋存状态及产出机理提供了数据及理论支撑。

关键词: 煤岩, 全孔径拼接, 微米CT扫描, 高压压汞, 液氮吸附, 二氧化碳吸附, 鄂东缘DJ区块

Abstract: 12 samples of X coal from the Benxi Formation were collected in the DJ Block at the eastern edge of Ordos Basin,in order to explore the pore structure of deep and ultra-deep coal formations.The full pore size distribution characteristics of X coal were characterized by multi-experiment splicing method,based onthe three-dimensional reconstruction technology of digital core CT scanning and tests of high-pressure mercury intrusion,liquid nitrogen adsorption,and carbon dioxide adsorption.The study also compared and analyzed the distribution differences between the micropores,mesopores,and macropores in deep,medium,and shallow coal formations and their effects on adsorption and permeability.The results show that the reserving space of coal reservoirs is dominated by micropores and macropores,with fewer mesopores.In deep X coal formation,micropores and macropores on average account for 44.1% and 53.9%,respectively.While in shallow-to-medium X coal,micropores and macropores on average account for 34.8%,64.1%,respectively.The adsorption nanopores in deep coal are more developed.However,the development of micron-scale fractures in shallow-to-medium coal is better than that in deep coal.Through the analysis of the full pore size distribution characteristics,it is concluded that the proportion of macropore volume in shallow-to-medium X coal is higher,and the permeability is an order of magnitude higher than that of deep X coal,while the proportion of micropore volume in deep X coal is higher,indicating stronger adsorption capacity.Through quantitative characterization of the full aperture,the pore distribution characteristics of the reservoir at all levels are clarified,which provides data and theoretical support for the occurrence state and production mechanism of coalbed methane.

Key words: coal, full pore size splicing, micron-scale CT scanning, high-pressure mercury intrusion, liquid nitrogen adsorption, carbon dioxide adsorption, DJ Block at the eastern edge of Ordos Basin

中图分类号:

TD822

朱文涛, 李小刚, 任勇, 师斌斌, 戴瑞瑞, 洪星, 杨潇, 陈国辉. 基于CT扫描的煤岩孔隙结构全孔径表征[J]. 特种油气藏, 2024, 31(4): 71-80.

Zhu Wentao, Li Xiaogang, Ren Yong, Shi Binbin, Dai Ruirui, Hong Xing, Yang Xiao, Chen Guohui. Full Pore Size Characterization of Coal Pore Structure Based on CT Scanning[J]. Special Oil & Gas Reservoirs, 2024, 31(4): 71-80.

参考文献

[1] 余恩晓,马立涛,周福双,等.煤岩孔隙结构分形特征表征方法研究[J].煤炭科学技术,2018,46(11):8-12.
YU Enxiao,MA Litao,ZHOU Fushuang,et al.Study on characterization method of fractal features of pore structure for coal rock[J].Coal Science and Technology,2018,46(11):8-12.
[2] 秦兴林.西山煤田不同变质程度煤孔隙结构分形特征及影响因素研究[J].中国矿业,2021,30(4):157-161.
QIN Xinglin.Study on the fractal feature of coal pore structure with different ranks and its influencing factors in Xishan Coal Field[J].China Mining Magazine,2021,30(4):157-161.
[3] 李军辉,吴海波,李跃,等.海拉尔盆地致密储层微观孔隙结构特征分析[J].中国矿业大学学报,2020,49(4):721-729.
LI Junhui,WU Haibo,LI Yue,et al.Microscopic pore structure characteristics of tight reservoir in Hailar Basin[J].Journal of China University of Mining & Technology,2020,49(4):721-729.
[4] ZHAO H,NING Z,WANG Q,et al.Petrophysical characterization of tight oil reservoirs using pressure-controlled porosimetry combined with rate-controlled porosimetry[J].Fuel, 2015,154:233-242.
[5] 卢杰林,傅雪海,康俊强.准南中低阶煤孔径结构全孔径定量综合表征[J].中国科技论文,2022,17(1):62-71.
LU Jielin,FU Xuehai,KANG Junqiang.Quantitative and comprehensive characterization of full pore size in medium and low rank coal in southern margin of Junggar Basin[J].China Science Paper,2022,17(1):62-71.
[6] 杨青,李剑,田文广,等.海拉尔盆地褐煤全孔径结构特征及影响因素[J].天然气地球科学,2020,31(11):1603-1614.
YANG Qing,LI Jian,TIAN Wenguang,et al.Characteristics on pore structures on full scale of lignite and main controlling factors in Hailar Basin[J].Natural Gas Geoscience,2020,31(11):1603-1614.
[7] 王凯,乔鹏,王壮森,等.基于二氧化碳和液氮吸附、高压压汞和低场核磁共振的煤岩多尺度孔径表征[J].中国矿业,2017,26(4):146-152.
WANG Kai,QIAO Peng,WANG Zhuangsen,et al.Multiple scale pore size characterization of coal based on carbon dioxide and liquid nitrogen adsorption, high-pressure mercury intrusion and low field nuclear magnetic resonance[J].China Mining Magazine,2017,26(4):146-152.
[8] 马文国,刘傲雄.CT扫描技术对岩石孔隙结构的研究[J].中外能源,2011,16(7):54-56.
MA Wenguo,LIU Aoxiong.The study of the pore structure parameters in rock by CT scanning technology[J].Sino-Global Energy,2011,16(7):54-56.
[9] 王刚,沈俊男,褚翔宇,等.基于CT三维重建的高阶煤孔裂隙结构综合表征和分析[J].煤炭学报,2017,42(8):2074-2080.
WANG Gang,SHEN Junnan,CHU Xiangyu,et al.Characterization and analysis of pores and fissures of high-rank coal based on CT three-dimensional reconstruction[J].Journal of China Coal Society,2017,42(8):2074-2080.
[10] 李五忠,陈刚,孙斌,等.大宁—吉县地区煤层气成藏条件及富集规律[J].天然气地球科学,2011,22(2):352-360.
LI Wuzhong,CHEN Gang,SUN Bin,et al.Geological controls of coalbed methane enrichment in Daning-Jixian Area,southeastern Ordos Basin[J].Natural Gas Geoscience,2011,22(2):352-360.
[11] 孙钦平,王生维.大宁—吉县煤区含煤岩系沉积环境分析及其对煤层气开发的意义[J].天然气地球科学,2006,17(6):874-879.
SUN Qinping,WANG Shengwei.The deposit environment analysis of the coal-bearing strata and its significance to the coalbed methane development in Daning-Jixian Region[J].Natural Gas Geoscience,2006,17(6):874-879.
[12] CLARKSONCR,BUSTINRM.The effect of pore structure and gas pressure upon the transport properties of coal: a laboratory and modeling study 1.isotherms and pore volume distributions[J].Fuel,1999,78:1333-1344.
[13] 谢广龙.贵州比德区块煤岩储层特征及富集主控因素分析[J].非常规油气,2019,6(1):14-22.
XIE Guanglong.Analysis of Characteristics and main controlling factors of coal reservoir in Bide Block, Guizhou[J].Unconventional Oil & Gas,2019,6(1):14-22.
[14] 李建新,胡博文,李斌.保德矿区煤岩煤质特征及成煤环境研究[J].中国矿业,2022,31(增刊1):192-197.
LI Jianxin,HU Bowen,LI Bin.Study on coal rock and coal quality characteristics and coal forming environment in Baode Mining Area[J].China Mining Magazine,2022,31(S1):192-197.
[15] 国家能源局.岩石三维孔隙结构测定方法:SY/T 7410.1—2018[S].北京:石油工业出版社,2018:1-8.
National Energy Administration.3D pore structure characterization of rocks:SY/T 7410.1-2018[S].Beijing:Petroleum Industry Press,2018:1-8.
[16] 国家市场监督管理总局,国家标准化管理委员会.岩石毛管压力曲线的测定:GB/T 29171—2023[S].北京:中国标准出版社,2023:1-20.
State Administration for Market Regulation,Standardization Administration of China.Rock capillary pressure measurement:GB/T 29171-2023[S].Beijing:China Standards Press,2023:1-20.
[17] 国家能源局.岩石比表面和孔径分布测定:SY/T 6154—2019[S].北京:石油工业出版社,2019:1-12.
National Energy Administration.Determination of specific surface and pore size distribution of rocks:SY/T 6154-2019[S].Beijing:Petroleum Industry Press,2019:1-12.
[18] 卢振东,刘成林,臧起彪,等.高压压汞与核磁共振技术在致密储层孔隙结构分析中的应用:以鄂尔多斯盆地合水地区为例[J].地质科技通报,2022,41(3):300-310.
LU Zhendong,LIU Chenglin,ZANG Qibiao,et al.Application of high pressure mercury injection and nuclear magnetic resonance in analysis of the pore structure of dense sandstone:a case study of the Heshui Area, Ordos Basin[J]. Bulletin of Geological Science and Technology,2022,41(3):300-310.
[19] 李阳,张玉贵,张浪,等.基于压汞、低温N₂吸附和CO₂吸附的构造煤孔隙结构表征[J].煤炭学报,2019,44(4):1188-1196.
LI Yang,ZHANG Yugui,ZHANG Lang, et al.Characterization on pore structure of tectonic coals based on the method of mercury intrusion, carbon dioxide adsorption and nitrogen adsorption[J].Journal of China Coal Society,2019,44(4):1188-1196.
[20] TODA Y,TOYODA S. Application of mercury porosimetry to coal[J].Fuel,1972,51:199-201.
[21] DEBELAK K A,SCHRODT J T.Comparison of pore stucture in Kentucky Coals by mercury penetrate on carbon dioxide adsorption[J].Fuel,1979,58:732-736.
[22] 刘玉龙,汤达祯,许浩,等.煤岩类型控制下的微观孔隙结构及吸附特征研究[J].煤炭工程,2016,48(11):107-110.
LIU Yulong,TANG Dazhen,XU Hao,et al.Study on micro-pore structure and adsorption characteristics under the control of coal rock type[J].Coal Engineering,2016,48(11):107-110.
[23] 刘璐,赵沉雷,崔占锋.甲烷吸附前后高阶煤煤岩孔隙结构变化特征研究[J].煤矿安全,2021,52(5):14-19.
LIU Lu,ZHAO Chenlei,CUI Zhanfeng.Change of pore structure for high rank coal before and after methane adsorption[J].Safety in Coal Mines,2021,52(5):14-19.
[24] 侯锦秀,王宝俊,张玉贵,等.不同煤级煤的微孔介孔演化特征及其成因[J].煤田地质与勘探,2017,45(5):75-81.
HOU Jinxiu,WANG Baojun,ZHANG Yugui,et al.Evolution characteristics of micropore and mesopore of different rank coal and cause of their formation[J].Coal Geology & Exploration,2017,45(5):75-81.
[25] 汪新光,郇金来,彭小东,等.基于数字岩心的致密砂岩储层孔隙结构与渗流机理[J].油气地质与采收率,2022,29(6):22-30.
WANG Xinguang,HUAN Jinlai,PENG Xiaodong,et al.Flow mechanism and pore structures of tight sandstone based on digital core analysis[J].Petroleum Geology and Recovery Efficiency,2022,29(6):22-30.
[26] 吴伟,梁志凯,郑马嘉,等.页岩储层孔隙结构与分形特征演化规律[J].油气地质与采收率,2022,29(4):35-45.
WU Wei,LIANG Zhikai,ZHENG Majia,et al.Pore structures in shale reservoirs and evolution laws of fractal characteristics[J].Petroleum Geology and Recovery Efficiency,2022,29(4):35-45.
[27] 代金友,林立新.储层孔隙的“渗流”分类方案及其意义[J].大庆石油地质与开发,2022,41(2):43-50.
DAI Jinyou,LIN Lixin. “Seepage”classification scheme of reservoir pores and its significance[J]. Petroleum Geology & Oilfield Development in Daqing,2022,41(2):43-50.
[28] 李奎周,王团,赵海波,等.基于深度前馈神经网络的致密砂岩储层孔隙度预测[J].大庆石油地质与开发,2023,42(5):140-146.
LI Kuizhou,WANG Tuan,ZHAO Haibo,et al.Porosity prediction of tight sandstone reservoir based on deep feedforward neural network[J]. Petroleum Geology & Oilfield Development in Daqing,2023,42(5):140-146.