JIN Zhi-min,ZHOU Hong-wei,XUE Dong-jie.Measurement of porosity and specific surface area of coal rock using CT images[J].Journal of Xi'an University of Science and Technology,2020,(01):133-140.





Measurement of porosity and specific surface area of coal rock using CT images
(中国矿业大学(北京)力学与建筑工程学院,北京 100083)
JIN Zhi-minZHOU Hong-weiXUE Dong-jie
(School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)
煤岩 CT图像 孔隙度 比表面积 MATLAB Avizo
coal rock CT image porosity specific surface area MATLAB Avizo
TP 391
为实现基于CT图像的煤岩孔隙度和比表面积快速测量,提出了一种基于MATLAB图像处理的测量方法。以平煤十二矿深部采集的煤岩为研究对象,应用Nano CT技术对样品进行了扫描,并分别借助Avizo和MATLAB软件计算孔隙度和比表面积,研究了Avizo三维建模和MATLAB图像处理2种方法的优缺点。发现2种方法计算出的结果误差仅在10%左右,且以复合Cotes公式的误差估计最小,孔隙度和比表面积的误差分别为9.392%和8.247%.结果表明:传统的基于Avizo三维建模的测量方法精确度较高,同时还能获取样品的三维孔隙网络模型和孔隙的形状、走向及孔径分布,但计算过程复杂,对于复数个试样必须进行多次计算,且对CT图像有较高的质量要求。基于MATLAB图像处理的测量方法则通过简单的数值积分实现了快速计算煤岩的孔隙度和比表面积,避免了三维建模,极大地降低了计算复杂度,且能够一次性处理复数个试样,较好地满足了实际工程需要。且对于CT图像具有更高的容错率,每次计算仅需其中数张扫描质量效果较好的CT图像即可。
In order to realize the rapid measurement of porosity and specific surface area of coal using CT images,a measurement method based on MATLAB image processing is proposed.Taking the coal rock obtained from the deep part of Pingdingshan Coal Mine Group 12 as the research object,the sample was scanned by Nano-CT,and the porosity and specific surface area were calculated by Avizo and MATLAB software respectively.The advantages and disadvantages of Avizo 3D modeling and MATLAB image processing were studied.It is pointed that the errors calculated by the two methods are only about 10%,with the error done by the composite Cotes formula the smallest.The errors of porosity and specific surface area are 9.392% and 8.247%,respectively.The results indicate that the traditional measurement method based on Avizo 3D modeling is more accurate,and the 3D pore network model and the shape,orientation and size distribution of pores can be obtained.However,the calculating process is comparatively complicated,and it is necessary to perform multiple calculations for a plurality of samples,with high quality requirements for CT images.The measurement method based on MATLAB image processing proposed in this paper realizes the rapid calculation of porosity and specific surface area of coal by simple numerical integration,which avoids 3D modeling,reduces the computational complexity greatly,and processes multiples at a time.The sample satisfies the engineering needs well.Moreover,for CT images,there is a higher fault tolerance rate,and only a few CT images with better scanning quality effects are needed for each calculation.


[1] Song L,Ning Z F,Duan L.Research on reservoir characteristics of Chang 7 tight oil based on nano-CT[J].Arabian Journal of Geosciences,2018,11(16):472. [2]徐 鹏,邱淑霞,姜舟婷,等.各向同性多孔介质中Kozeny-Carman常数的分形分析[J].重庆大学学报,2011,34(4):78-82. XV Peng,QIU Shu-xia,JIANG Zhou-ting,et al.Fractal analysis of Kozeny-Carman constant in the homogenous porous media[J].Journal of Chongqing University,2011,34(4):78-82. [3]Zhang R,Liu S,Bahadur J,et al.Changes in pore structure of coal caused by coal-to-gas bioconversion[J].Scientific Reports,2017,7(1):3840. [4]Rodrigues C F,Sousa M J L D.The measurement of coal porosity with different gases[J].International Journal of Coal Geology,2002,48(3):245-251. [5]Li X,Kang Y,Haghighi M.Investigation of pore size distributions of coals with different structures by nuclear magnetic resonance(NMR)and mercury intrusion porosimetry(MIP)[J].Measurement,2018,116:122-128. [6]Liu S,Sang S,Wang G,et al.FIB-SEM and X-ray CT characterization of interconnected pores in high-rank coal formed from regional metamorphism[J].Journal of Petroleum Science and Engineering,2017,148:21-31. [7]Karacan C O,Okandan E.Adsorption and gas transport in coal microstructure:investigation and evaluation by quantitative X-ray CT imaging[J].Fuel,2001,80(4):509-520. [8]宫伟力,李 晨.煤岩结构多尺度各向异性特征的SEM图像分析[J].岩石力学与工程学报,2010,29(4):2681-2689. GONG Wei-li,LI Chen.Multi-scale and anisotropic characterization of coal structure based on SEM image analysis[J].Chinese Journal of Rock Mechanics & Engineering,2010,29(4):2681-2689. [9]Zhang G,Ranjith P G,Perera M S A,et al.Characterization of coal porosity and permeability evolution by demineralisation using image processing techniques:A micro-computed tomography study[J].Journal of Natural Gas Science & Engineering,2018,56(8):384-396. [10]Mayo S,Josh M,Kasperczyk D,et al.Dynamic micro-CT study of gas uptake in coal using Xe,Kr and CO2[J].Fuel,2018,212:140-150. [11]王 刚,杨鑫祥,张孝强,等.基于CT三维重建的煤层气非达西渗流数值模拟[J].煤炭学报,2016,41(4):931-940. WANG Gang,YANG Xin-xiang,ZHANG Xiao-qiang,et al.Numerical simulation on non-Darcy seepage of CBM by means of 3D reconstruction based on computed tomography[J].Journal of China Coal Society,2016,41(4):931-940. [12]李 伟,要惠芳,刘鸿福,等.基于显微CT的不同煤体结构煤三维孔隙精细表征[J].煤炭学报,2014,39(6):1127-1132. LI Wei,YAO Hui-fang,LIU Hong-fu,et al.Advanced characterization of three-dimensional pores in coals with different coal-body structure by Micro-CT[J].Journal of China Coal Society,2014,39(6):1127-1132. [13]Pan X C,Xia D,Zou Y,et al.A unified analysis of FBP-based algorithms in helical cone-beam and circular cone-and fan-beam scans[J].Physics and Medicine & Biology,2004,49(18):4349-4369. [14]Liu X,Comtat C,Michel C,et al.Comparison of 3-D reconstruction with 3D-OSEM and with FORE+OSEM for PET[J].IEEE Transactions on Medical Imaging,2001,20(8):804-814. [15]David S,Burion S,Tepe A,et al.Experimental validation of an OSEM-type iterative reconstruction algorithm for inverse geometry computed tomography[C]//Medical Imaging 2012:Physics of Medical Imaging. International Society for Optics and Photonics,2012,8313(6):125. [16]Herman G T,Meyer L B.Algebraic reconstruction techniques can be made computationally efficient[positron emission tomography application][J].IEEE Transactions on Medical Imaging,1993,12(3):600. [17]Peyrin F,Dong P,Pacureanu A,et al.Micro-and nano-CT for the study of bone ultrastructure[J].Current Osteoporosis Reports,2014,12(4):465-474. [18]刘郁纪.X射线工业CT物理设计及图像重建[D].兰州:兰州大学,2010. LIU Yu-ji.The physical design and image reconstruction of X-ray CT[D].Lanzhou:Lanzhou University,2010. [19]李 光,罗守华,顾 宁.Nano CT成像进展[J].科学通报,2013,58(7):501-509. LI Guang,LUO Shou-hua,GU Ning.Research progress of Nano CT imaging[J].Chinese Science Bulletin,2013,58(7):501-509. [20]陶 鹏.基于数字岩心的低渗储层微观渗流机理研究[D].成都:西南石油大学,2017. TAO Peng.Mechanism of micro seepage in low-permeability reservoirs based on digital core[D].Chengdu:Southwest Petroleum University,2017. [21]Flamant J,Chainais P,Bihan N L.A complete framework for linear filtering of bivariate signals[J].IEEE Transactions on Signal Processing,2018,66(17):4541-4552. [22]孙宏琦,施维颖,巨永锋.利用中值滤波进行图像处理[J].长安大学学报(自然科学版),2003,23(2):104-106. SUN Hong-qi,SHI Wei-ying,JU Yong-feng.Image processing with medium value filter[J].Journal of Chang'an University(Natural Science Edition),2003,23(2):104-106. [23]Huang T,Yang G,Tang G.A fast two-dimensional median filtering algorithm[J].IEEE Transactions on Acoustics,Speech and Signal Processing,1979,27(1):13-18. [24]张旭明,徐滨士,董世运.用于图像处理的自适应中值滤波[J].计算机辅助设计与图形学学报,2005,17(2):295-299. ZHANG Xu-ming,XV Bin-shi,DONG Shi-yun.Adaptive median filtering for image processing[J].Journal of Computer-Aided Design & Computer Graphics,2005,17(2):295-299. [25]Althahab,Jumaah A Q.A new robust adaptive algorithm based adaptive filtering for noise cancellation[J].Analog Integrated Circuits and Signal Processing,2018,94(2):217-231. [26]钟江城,周宏伟,任伟光,等.基于CT图像灰度分布的含杂质煤体三值化方法[J].力学与实践,2018,40(2):140-147. ZHONG Jiang-cheng,ZHOU Hong-wei,REN Wei-guang,et al.A three-value-segmentation method of coal containing inclusion based on gray distribution of computed tomography image[J].Mechanics in Engineering,2018,40(2):140-147.


收稿日期:2019-01-11 责任编辑:李克永
基金项目:国家自然科学基金(51972201); 中国博士后科学基金(2019M663607); 陕西省自然科学基础研究计划(2018JQ2049); 陕西省教育厅专项科研计划项目(18JK0106); 陕西科技大学博士启动金(2016BJ-75)
通信作者:方 园(1986-),女,陕西西安人,博士,讲师,E-mail:fangy@sust.edu.cn
更新日期/Last Update: 2020-02-15