刘一楠¹,刘勇¹,辛福东²,魏宏宇²
LIU Yinan¹, LIU Yong¹, XIN Fudong², WEI Hongyu²

• 1:中联煤层气有限责任公司，北京 100011
• 2:中国地质大学(北京) 能源学院，北京 100083

摘要(Abstract)：

压汞实验在中-高阶煤的孔隙测试中得到了广泛的应用。然而对于低阶煤，由于其煤体疏松、易碎，压汞的增压过程会造成孔隙结构破坏，导致实验结果不准。为了准确评估压汞实验对低阶煤孔隙结构的损伤，选取褐煤和长焰煤为研究对象，同时利用压汞与核磁共振测试煤的孔径分布。结果表明，压实与凝胶化程度低的褐煤和长焰煤，压汞测试过程破坏了其大中孔的原生结构，从而导致中孔比例升高；同时受基质压缩效应影响导致微孔体积偏高。随着煤化作用增强，长焰煤较褐煤所受的影响逐渐减小。进一步通过氮气吸附实验对压汞高压段的测试结果进行校正，以消除基质压缩效应引起的煤体弹性变形所带来的误差，其中，褐煤压汞校正前测试误差为87%，而校正后仅为18%。实验研究表明，联合利用核磁共振测试、氮气吸附实验可显著提高压汞法用于低阶煤孔隙测试结果的准确性。
As an effective method for coal reservoir characterization, mercury intrusion has been widely used in reservoir property analysis of medium-high rank coal. However, for low-rank coal, due to its loose and brittle nature, the process of mercury intrusion will destroy the pore structure, resulting in poor applicability of mercury intrusion experiments. In order to accurately assess the damage to the pore structure of low-rank coal by mercury intrusion experiments, lignite and long flame coal were selected as the research objects, and the pore size distribution of coal was tested by mercury intrusion and nuclear magnetic resonance. The results show that for lignite and long-flame coal with a low degree of compaction and gelification, the mercury intrusion test process destroys the primary structure of the macro-mesopores, resulting in an increase in the proportion of mesopores. At the same time, the micropore volume is too high due to the matrix compression effect. With the increase of coalification, the influence on long-flame coal is less than that on lignite. Moreover, nitrogen adsorption results were used to correct the test results of mercury injection under high pressure, eliminating the influence of elastic deformation caused by high pressure. The results show that the test error of lignite mercury intrusion before calibration is 87%, while after calibration it is only 18%. Experimental studies have shown that the combined use of nuclear magnetic resonance testing and nitrogen adsorption experiments can significantly improve the accuracy of mercury intrusion method used in low-rank coal pore test results.

关键词(KeyWords)： 低阶煤;褐煤;核磁共振;压汞;孔径分布
low-rank coal;lignite;NMR;mercury intrusion;pore size distribution

Abstract:

Keywords:

基金项目(Foundation): 国家自然科学基金项目（U1703126）

作者(Author): 刘一楠¹,刘勇¹,辛福东²,魏宏宇²
LIU Yinan¹, LIU Yong¹, XIN Fudong², WEI Hongyu²

DOI: 10.3969/j.issn.1001-1986.2020.04.017

参考文献(References)：

• [1] 孙钦平,王生维,田文广,等. 二连盆地吉尔嘎朗图凹陷低煤阶煤层气富集模式[J]. 天然气工业,2018,38(4):59-66. SUN Qinping,WANG Shengwei,TIAN Wenguang,et al. Accumulation patterns of low-rank coalbed methane gas in the Jiergalangtu Sag of the Erlian basin[J]. Natural Gas Industry,2018,38(4):59-66.
  [2] 孙粉锦,田文广,陈振宏,等. 中国低煤阶煤层气多元成藏特征及勘探方向[J]. 天然气工业,2018,38(6):10-18. SUN Fenjin,TIAN Wenguang,CHEN Zhenhong,et al. Low-rank coalbed methane gas pooling in China:Characteristics and exploration orientation[J]. Natural Gas Industry,2018,38(6):10-18.
  [3] 刘爱华,傅雪海,梁文庆,等. 不同煤阶煤孔隙分布特征及其对煤层气开发的影响[J]. 煤炭科学技术,2013,41(4):104-108. LIU Aihua,FU Xuehai,LIANG Wenqing,et al. Pore distribution features of different rank coal and influences to coalbed methane development[J]. Coal Science and Technology,2013,41(4):104-108.
  [4] 李振,邵龙义,侯海海,等. 高煤阶煤孔隙结构及分形特征[J]. 现代地质,2017,31(3):595-605. LI Zhen,SHAO Longyi,HOU Haihai,et al. Pore structures and fractal characteristics of high rank coals[J]. Geoscience,2017,31(3):595-605.
  [5] 吴双,汤达祯,许浩,等. 中-高煤阶煤岩孔隙发育特征[J]. 煤田地质与勘探,2016,44(6):69-74. WU Shuang,TANG Dazhen,XU hao,et al. Characteristics of pore development in medium-high rank coal[J]. Coal Geology & Exploration,2016,44(6):69-74.
  [6] 郑司建,王小垚,周三栋. 准噶尔盆地南缘低煤阶煤储层孔隙分形特征[J]. 煤炭技术,2017,36(7):133-135. ZHENG Sijian,WANG Xiaoyao,ZHOU Sandong,et al. Fractal dimension of low-rank coal reservoir pore in southern margin of Junggar basin[J]. Coal Technology,2017,36(7):133-135.
  [7] 董夔,贾建称,巩泽文,等. 淮北许疃矿构造煤孔隙结构及压敏效应[J]. 煤田地质与勘探,2019,47(2):58-65. DONG Kui,JIA Jiancheng,GONG Zewen,et al. Study on pore structure and pressure-sensitive effect of tectonic coal in Huaibei Xutuan mine[J]. Coal Geology & Exploration,2019,47(2):58-65.
  [8] FU Haijiao,TANG Dazhen,XU Ting,et al. Characteristics of pore structure and fractal dimension of low-rank coal:A case study of Lower Jurassic Xishanyao coal in the southern Junggar basin,NW China[J]. Fuel,2017,193:254-264.
  [9] 郑司建,姚艳斌,蔡益栋,等. 准噶尔盆地南缘低煤阶煤储层可动流体及孔径分布特征[J]. 煤田地质与勘探,2018,46(1):56-60. ZHENG Sijian,YAO Yanbin,CAI Yidong,et al. Characteristics of movable fluid and pore size distribution of low rank coals reservoir in southern margin of Junggar basin[J]. Coal Geology & Exploration,2018,46(1):56-60.
  [10] FU Haijiao,TANG Dazhen,XU Hao,et al. Abrupt changes in reservoir properties of low-rank coal and its control factors for methane adsorbability[J]. Energy & Fuels,2016,30(3):2084-2094.
  [11] 孟智强,郭和坤,周尚文,等. 核磁共振可动流体实验最佳离心力确定新方法研究[J]. 科学技术与工程,2013,13(25):7307-7311. MENG Zhiqiang,GUO Hekun,ZHOU Shangwen,et al. Research of new method to calibrate the optimum centrifugal force for nuclear magnetic resonance movable fluid experiment[J]. Science Technology and Engineering,2013,13(25):7307-7311.
  [12] 朱林奇,张冲,石文睿,等. 结合压汞实验与核磁共振测井预测束缚水饱和度方法研究[J]. 科学技术与工程,2016,16(15):22-29. ZHU Linqi,ZHANG Chong,SHI Wenrui,et al. Study on the method of prediction of irreducible water saturation by combining mercury intrusion and nmr logging data[J]. Science Technology and Engineering,2016,16(15):22-29.
  [13] 宁传祥,姜振学,苏思远,等. 泥页岩核磁共振T2谱换算孔隙半径方法[J]. 科学技术与工程,2016,16(27):14-19. NING Chuanxiang,JIANG Zhenxue,SU Siyuan,et al. Method for calculating pore radius distribution in shale reservoirs from NMR T2 spectra[J]. Science Technology and Engineering,2016,16(27):14-19.
  [14] XU Hao,TANG Dazhen,CHEN Yanpeng,et al. Effective porosity in lignite using kerosene with low-field nuclear magnetic resonance[J]. Fuel,2018,213:158-163.
  [15] 何法,祝捷,张博,等. 对煤的压汞实验数据的压缩性修正[C]//北京力学会第二十三届学术年会会议论文集. 北京:北京力学会,2017:458-459. HE Fa,ZHU Jie,ZHANG Bo,et al. Compressibility correction of experimental data of mercury injection in coal[C]//Proceedings of the 23rd Academic Year Conference of the Beijing Society of Theoretical and Applied Mechanics. Beijing:Beijing Society of Theoretical and Applied Mechanics,2017:458-459.

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