A New Method for Microscopic Pore Structure Analysis in Shale Matrix
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摘要: 页岩基质孔隙主要包含有机孔隙和无机孔隙，页岩油气在有机孔隙和无机孔隙中的渗流机理不同，对页岩中有机孔隙和无机孔隙的微观结构进行定量表征具有重要意义.首先通过扫描电子显微镜(scanning electron microscope，简称SEM)实验分别获取具有代表性的页岩无机孔隙和有机孔隙扫描电镜图像，其中，无机孔隙相对较大，其图像的分辨率较低，有机孔隙相对较小，其图像的分辨率较高；然后，通过图像处理和马尔可夫链蒙特卡洛(Markov chain Monte Carlo，简称MCMC)法重构出相应的无机孔隙数字岩心和有机孔隙数字岩心，并提出局部叠加法构建同时包含无机孔隙和有机孔隙的页岩基质孔隙数字岩心；最后对无机孔隙数字岩心、有机孔隙数字岩心和基质孔隙数字岩心的结构特征进行了对比分析.结果表明，局部叠加法构建的页岩基质孔隙数字岩心能够同时描述页岩中的无机孔隙和有机孔隙结构特征，无机孔隙本身连通性较差，有机孔隙本身连通性较好，有机孔隙的局部孔隙度和局部渗透率较高，对页岩中的流体渗流有着重要作用.该方法为页岩中不同的孔隙结构特征描述和油气在纳米尺度孔隙中的传输模拟提供了一个可靠的研究平台.Abstract: It is important to quantitatively characterize the microscopic structures of organic and inorganic shale pores making up shale matrix, since shale gas and oil show different transport mechanisms in them. In this paper, the typical shale organic pore and inorganic pore images are obtained from scanning electron microscope (SEM) respectively, and it is found that the image with relatively larger inorganic pores has a lower resolution, while the image with relatively smaller organic pores has a higher resolution. Then, image processing and Markov chain Monte Carlo (MCMC) method are used to reconstruct the corresponding inorganic pore digital rock and organic pore digital rock, and local superposition method is introduced to construct the shale matrix pore digital rock including inorganic pores and organic pores. At last, the structure properties are compared and analyzed among the three inorganic pore, organic pore and matrix pore digital rocks. Results show that the constructed shale matrix pore digital rock with local superposition method could describe the inorganic pore and organic pore structures simultaneously. In addition the inorganic pores have a poor connection while the organic pores have a better connection, and a higher local porosity and local permeability, which is important to the fluid flow in shale rocks.A reliable research platform is established for different pore structure analysis and gas & oil transport simulation in nanoscopic pores of shale rocks in this study.
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Key words:
- shale matrix /
- SEM /
- digital rock /
- pore structure analysis /
- local superposition method /
- petroleum geology
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图 2 页岩不同孔隙的代表性SEM图像
a.页岩无机孔隙；b.页岩有机孔隙
Fig. 2. Different typical pore SEM images in shale rock
图 3 页岩不同孔隙二值图像
a.页岩无机孔隙；b.页岩有机孔隙；白色表示岩石骨架，黑色表示岩石孔隙
Fig. 3. Binary images of different pores in shale rocks
图 4 基于MCMC法重构的数字岩心
a.无机孔隙数字岩心；b.有机孔隙数字岩心
Fig. 4. The reconstructed digital rock with MCMC method
图 5 基于局部叠加法构建的页岩基质孔隙数字岩心
Fig. 5. Shale matrix pore digital rock with local superposition method
图 6 基于数字岩心提取得到的孔隙网络模型
a.无机孔隙网络模型；b.有机孔隙网络模型；c.页岩基质孔隙网络模型
Fig. 6. Pore network model extracted from digital rock
图 7 页岩不同孔隙网络模型结构特征对比
a.孔隙半径分布；b.形状因子分布；c.喉道长度分布；d.配位数分布
Fig. 7. Structure properties comparison of different pore network models in shale rocks
表 1 页岩不同孔隙网络模型基本结构参数
Table 1. Basic structure parameters of different pore network model in shale rock
网络模型参数 无机孔隙网络模型 有机孔隙网络模型 基质孔隙网络模型 模型尺寸(μm3) 3.0×3.0×3.0 1.5×1.5×1.5 3.0×3.0×3.0 孔隙数目(个） 4735 67647 69011 喉道数目(个） 6472 116804 123106 平均配位数 2.71447 3.447 54 3.562 42 网络孔隙度 0.071 0.127 0.115 绝对渗透率(nD) 2.3 10.8 7.7 
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Bai, B., Elgmati, M., Zhang, H., et al., 2013.Rock Characterization of Fayetteville Shale Gas Plays.Fuel, 105:645-652.doi: 10.1016/j.fuel.2012.09.043 Blunt, M.J., 1998.Physically-Based Network Modeling of Multiphase Flow in Intermediate-Wet Porous Media.Journal of Petroleum Science and Engineering, 20(3-4):117-125.doi: 10.1016/S0920-4105(98)00010-2 Bryant, S., Blunt, M., 1992.Prediction of Relative Permeability in Simple Porous Media.Physical Review A, 46(4):2004-2011.doi: 10.1103/physreva.46.2004 Dunsmuir, J.H., Ferguson, S.R., D'Amico, K.L., et al., 1991.X-Ray Microtomography: A New Tool for the Characterization of Porous Media.SPE Annual Technical Conference and Exhibition, Dallas. https://www.researchgate.net/publication/264051414_Lattice-Boltzmann_simulation_of_microscale_CH4_flow_in_porous_rock_subject_to_force-induced_deformation Fredrich, J.T., Menendez, B., Wong, T.F., 1995.Imaging the Pore Structure of Geomaterials.Science, 268(5208):276-279.doi: 10.1126/science.268.5208.276 Hazlett, R.D., 1997.Statistical Characterization and Stochastic Modeling of Pore Networks in Relation to Fluid Flow.Mathematical Geology, 29(6):801-822.doi: 10.1007/BF02768903 Jiang, Z., van Dijke, M.I.J., Wu, K., et al., 2012.Stochastic Pore Network Generation from 3D Rock Images.Transport in Porous Media, 94(2):571-593.doi: 10.1007/s11242-011-9792-z Li, J.J., Shi, Y.L., Zhang, X.W., et al., 2014.Control Factors of Enrichment and Producibility of Shale Oil:A Case Study of Biyang Depression.Earth Science, 39(7):848-857 (in Chinese with English abstract). http://earth-science.net/WebPage/Article.aspx?id=2888 Loucks, R.G., Reed, R.M., Ruppel, S.C., et al., 2012.Spectrum of Pore Types and Networks in Mudrocks and a Descriptive Classification for Matrix-Related Mudrock Pores.AAPG Bulletin, 96(6):1071-1098.doi: 10.1306/08171111061 Okabe, H., Blunt, M.J., 2004.Prediction of Permeability for Porous Media Reconstructed Using Multiple-Point Statistics.Physical Review E, 70(6):066135.doi: 10.1103/physreve.70.066135 Quiblier, J.A., 1984.A New Three-Dimensional Modeling Technique for Studying Porous Media.Journal of Colloid and Interface Science, 98(1):84-102.doi: 10.1016/0021-9797(84)90481-8 Rushing, J.A.K.E., Newsham, K.E., Blasingame, T.A., 2008.Rock Typing: Keys to Understanding Productivity in Tight Gas Sands.Unconventional Reservoirs Conference, Keystone, Colorado. https://www.researchgate.net/publication/279449296_Rock_Typing_of_Tight_Gas_Sands_A_Case_Study_in_Lance_and_Mesaverde_Formations_From_Jonah_Field Sisk, C., Diaz, E., Walls, J., et al., 2010.3D Visualization and Classification of Pore Structure and Pore Filling in Gas Shales.SPE Annual Technical Conference and Exhibition, Florence. Sun, H., Yao, J., Zhang, L., et al., 2014.A Computing Method of Shale Permeability Based on Pore Structures.Journal of China University of Petroleum (Edition of Natural Science), 38(2):92-98 (in Chinese with English abstract). https://www.researchgate.net/publication/286940331_A_computing_method_of_shale_permeability_based_on_pore_structures Tomutsa, L., Silin, D.B., Radmilovic, V., 2007.Analysis of Chalk Petrophysical Properties by Means of Submicron-Scale Pore Imaging and Modeling.SPE Reservoir Evaluation and Engineering, 10(3):285-293.doi: 10.2118/99558-pa van Dijke, M.I.J., Piri, M., 2007.Introduction to Special Section on Modeling of Pore-Scale Processes.Water Resources Research, 43(12): W12S01.doi: 10.1029/2007WR006332 Wang, C., Yao, J., Wu, K., et al., 2014.Organic and Inorganic Pore Structure Analysis in Shale Matrix with Superposition Method.Unconventional Resources Technology Conference, Denver.[doi: 10.15530/urtec-2014-1922283] Wildenschild, D., Sheppard, A.P., 2013.X-Ray Imaging and Analysis Techniques for Quantifying Pore-Scale Structure and Processes in Subsurface Porous Medium Systems.Advances in Water Resources, 51:217-246.doi: 10.1016/j.advwatres.2012.07.018 Wu, K., Ma, Q.F., Feng, Q.L., et al., 2012.Middle Permian Pore Characteristics and Shale Gas Exploration Significance from the Gufeng Formation in Jianshi, Western Hubei.Earth Science, 37(Suppl.2):175-183 (in Chinese with English abstract). https://www.researchgate.net/publication/278398900_MPG-pore_structure2015 Wu, K.J., Nunan, N., Crawford, J.W., et al., 2004.An Efficient Markov Chain Model for the Simulation of Heterogeneous Soil Structure.Soil Science Society of America Journal, 68(2):346-351.doi: 10.2136/sssaj2004.3460 Wu, K.J., van Dijke, M.I.J., Couples, G.D., et al., 2006.3D Stochastic Modelling of Heterogeneous Porous Media-Applications to Reservoir Rocks.Transport in Porous Media, 65(3):443-467.doi: 10.1007/s11242-006-0006-z Wu, S.T., Zou, C.N., Zhu, R.K., et al., 2015.Reservoir Quality Characterization of Upper Triassic Chang7 Shale in Ordos Basin.Earth Science, 40(11):1810-1823 (in Chinese with English abstract). http://earth-science.net/WebPage/Article.aspx?id=3188 Xiong, C.R., Tang, H.M., Liu, B.C., et al., 2007.Using SEM Photos to Gain the Pore Structural Parameters of Soil Samples.Earth Science, 32(3):415-419 (in Chinese with English abstract). http://earth-science.net/WebPage/Article.aspx?id=3469 Yang, Y.F., Yao, J., Wang, C.C., et al., 2015.New Pore Space Characterization Method of Shale Matrix Formation by Considering Organic and Inorganic Pores.Journal of Natural Gas Science and Engineering, 27(2):496-503.doi: 10.1016/j.jngse.2015.08.017 Yao, J., Sun, H., Huang, Z.Q., et al., 2013.Key Mechanical Problems in the Development of Shale Gas Reservoirs.Scientia Sinica:Physica, Mechanica & Astronomica, 43(12):1527-1547 (in Chinese with English abstract). Zhang, L.Y., Li, J.Y., Li, Z., et al., 2015.Development Characteristics and Formation Mechanism of Intra-Organic Reservoir Space in:Acustrine Shales.Earth Science, 40(11):1824-1833 (in Chinese with English abstract). http://earth-science.net/WebPage/Article.aspx?id=3189 Zhao, J.P., Sun, J.M., Jiang, L.M., et al., 2014.Effects of Cementation on Elastic Property and Permeability of Reservoir Rocks.Earth Science, 39(6):769-774 (in Chinese with English abstract). http://earth-science.net/WebPage/Article.aspx?id=2883 李吉君, 史颖琳, 章新文, 等, 2014.页岩油富集可采主控因素分析:以泌阳凹陷为例.地球科学, 39(7): 848-857. http://earth-science.net/WebPage/Article.aspx?id=2888 孙海, 姚军, 张磊, 等, 2014.基于孔隙结构的页岩渗透率计算方法.中国石油大学学报(自然科学版), 38(2): 92-98. http://www.cnki.com.cn/Article/CJFDTOTAL-SYDX201402014.htm 吴勘, 马强分, 冯庆来, 2012.鄂西建始中二叠世孤峰组孔隙特征及页岩气勘探意义.地球科学, 37(增刊2): 175-183. https://www.researchgate.net/publication/279038133_Components_and_processes_affecting_producibility_and_commerciality_of_shale_resource_systems 吴松涛, 邹才能, 朱如凯, 等, 2015.鄂尔多斯盆地上三叠统长7段泥页岩储集性能.地球科学, 40(11): 1810-1823. http://earth-science.net/WebPage/Article.aspx?id=3188 熊承仁, 唐辉明, 刘宝琛, 等, 2007.利用SEM照片获取土的孔隙结构参数.地球科学, 32(3): 415-419. http://earth-science.net/WebPage/Article.aspx?id=3469 姚军, 孙海, 黄朝琴, 等, 2013.页岩气藏开发中的关键力学问题.中国科学:物理学、力学、天文学, 43(12): 1527-1547. http://www.cnki.com.cn/Article/CJFDTOTAL-JGXK201312002.htm 张林晔, 李钜源, 李政, 2015.湖相页岩有机储集空间发育特点与成因机制.地球科学, 40(11): 1824-1833. http://earth-science.net/WebPage/Article.aspx?id=3189 赵建鹏, 孙建孟, 姜黎明, 等, 2014.岩石颗粒胶结方式对储层岩石弹性及渗流性质的影响.地球科学, 39(6): 769-774. http://earth-science.net/WebPage/Article.aspx?id=2883 -
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