Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-25T04:13:55.358Z Has data issue: false hasContentIssue false
  • English
  • Français

Variations in the morphology of porosity in the Boom Clay Formation: insights from 2D high resolution BIB-SEM imaging and Mercury injection Porosimetry

Published online by Cambridge University Press:  25 March 2014

S. Hemes ,
G. Desbois ,
J.L. Urai ,
M. De Craen  and
M. Honty
S. Hemes*
Affiliation:
Structural Geology, Tectonics and Geomechanics, Energy and Mineral Resources Group, RWTH Aachen University, Lochnerstrasse 4-20, 52056 Aachen, Germany
G. Desbois
Affiliation:
Structural Geology, Tectonics and Geomechanics, Energy and Mineral Resources Group, RWTH Aachen University, Lochnerstrasse 4-20, 52056 Aachen, Germany
J.L. Urai
Affiliation:
Structural Geology, Tectonics and Geomechanics, Energy and Mineral Resources Group, RWTH Aachen University, Lochnerstrasse 4-20, 52056 Aachen, Germany
M. De Craen
Affiliation:
SCK-CEN, Belgian Nuclear Research Centre, Environment, Health and Safety Institute, Waste & Disposal Expert Group, Boeretang 200, 2400 Mol, Belgium
M. Honty
Affiliation:
SCK-CEN, Belgian Nuclear Research Centre, Environment, Health and Safety Institute, Waste & Disposal Expert Group, Boeretang 200, 2400 Mol, Belgium
*
Email: [email protected]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Boom Clay is considered as one of the potential host rocks for the disposal of high level and/or long lived radioactive waste in a geological formation in Belgium (Mol study site, Mol-1 borehole) and the Netherlands. The direct characterisation of the pore space is essential to help understand the transport properties of radionuclides in argillaceous materials.

This contribution aims to characterise and compare the morphology of the pore space in different Boom Clay samples, representing end-members with regard to mineralogy (i.e. clay content) and grain-size distribution of this formation. Broad ion beam (BIB) cross-sectioning is combined with SEM imaging of porosity and Mercury injection Porosimetry (MIP) to characterise the variability of the pore space in Boom Clay at the nm- to μm-scale within representative 2D areas and to relate microstructural observations to fluid flow properties of the bulk sample material. Segmented pores in 2D BIB surfaces are classified according to the mineralogy, generating representative datasets of up to 100,000 pores per cross-section.

Results show total SEM-resolved porosities of 10-20% and different characteristic mineral phase internal pore morphologies and intra-phase porosities.

Most of the nano-porosity resides in the clay matrix. In addition, in the silt-rich samples, larger inter-aggregate pores contribute to a major part of the resolved porosity. Pore-size distributions within the clay matrix suggest power-law behaviour of pore areas with exponents between 1.56-1.74. Mercury injection Porosimetry, with access to pore-throat diameters down to 3.6 nm, shows total interconnected porosities between 27-35 Vol.-%, and the observed hysteresis in the MIP intrusion vs. extrusion curves suggests relatively high pore-body to pore-throat ratios in Boom Clay. The difference between BIB-SEM visible and MIP measured porosities is explained by the resolution limit of the BIB-SEM method, as well as the limited size of the BIB-polished cross-section areas analysed. Compilation of the results provides a conceptual model of the pore network in fine- and coarse-grained samples of Boom Clay, where different mineral phases show characteristic internal porosities and pore morphologies and the overall pore space can be modelled based on the distribution of these mineral phases, as well as the grain-size distribution of the samples investigated.

Keywords

Boom Claybroad-ion-beam millingMercury injection Porosimetrypore morphologiespore-size distributionSEM-imaging
Type
Research Article
Information
Netherlands Journal of Geosciences , Volume 92 , Issue 4 , December 2013 , pp. 275 - 300
Copyright
Copyright © Stichting Netherlands Journal of Geosciences 2013

References

Abell, A.B., Willis, K.L. & Lange, D.A., 1999. Mercury intrusion porosimetry and image analysis of cement-based materials. Journal of Colloid and Interface Science 211: 39–44. www.sciencedirect.com/science/article/pii/S0021979798959860 CrossRefGoogle ScholarPubMed
Adamic, L.A. & Huberman, B.A., 2002. Zipf's law and the internet. Glottometrics 3: 143–150. www.hpl.hp.com/research/idl/papers/ranking/adamicglottometrics.pdf Google Scholar
Aertsens, M., Dierckx, A., Put, M., Moors, H., Janssen, K., Van Ravestyn, L., Van Gompel, M. & De Cannière, P., 2005a. Determination of the hydraulic conductivity, the product ηr of the porosity η and the retardation factor r, and the apparent diffusion coefficient Dp on Boom Clay cores from the Mol-1 drilling. Restricted Contract Report SCK-CEN-R-3503 (Mol, Belgium).Google Scholar
Aertsens, M., Dierckx, A., Put, M., Moors, H., Janssen, K., Van Ravestyn, L., Van Gompel, M. & De Cannière, P., 2005b. Determination of the hydraulic conductivity, ηr and the apparent diffusion coefficient on Ieper Clay and Boom Clay cores from the Doel-1 and Doel-2b drillings. Restricted Contract Report R-3589, SCK-CEN (Mol, Belgium).Google Scholar
Aertsens, M., Van Gompel, M., De Cannière, P., Maes, N. & Dierckx, A., 2008. Vertical distribution of H14CO3 transport parameters in Boom Clay in the Mol-1 borehole (Mol, Belgium): Clays in natural and engineered barriers for radioactive waste confinement. Physics and Chemistry of the Earth, Parts A/B/C, 33, Supplement 1 33: 61–66. http://publications.sckcen.be/dspace/handle/10038/1022 Google Scholar
Al-Mukhtar, M., Belanteur, N., Tessier, D. & Vanapalli, S.K., 1996. The fabric of a clay soil under controlled mechanical and hydraulic stress states. Applied Clay Science 11: 99–115. www.sciencedirect.com/science/article/pii/S0169131796000233 CrossRefGoogle Scholar
Baeyens, B., Maes, A. & Cremers, A., 1985. In-situ physico-chemical characterization of Boom Clay. Radioactive Waste Management and the Nuclear Fuel Cycle 6: 391–408.Google Scholar
Bak, P., 1996. How nature works: The science of self organized criticality. Springer (New York), 212 pp.CrossRefGoogle Scholar
Bartoli, F., Bird, N.R.A., Gomendy, V., Vivier, H. & Niquet, S., 1999. The relation between silty soil structures and their Mercury Porosimetry curve counterparts: Fractals and percolation. European Journal of Soil Science 50: 9–22. http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2389.1999.00209.x/abstract; jsessionid=7121D5405928DFEC6B06624343B10CEE.d03t03Google Scholar
Bell, J., Boateng, A., Olawale, O. & Roberts, D., 2011. The influence of fabric arrangement on oil sand samples from the estuarine depositional environment of the upper McMurray Formation. Search and Discovery Article 80197. www.searchanddiscovery.com/abstracts/html/2011/ice/abstracts/abstracts057.html Google Scholar
Bésuelle, P., Viggiani, G., Lenoir, N., Desrues, J. & Bornert, M., 2006. X-ray micro CT for studying strain localization in clay rocks under triaxial compression. In: Desrues, J., Viggiani, G. & Bésuelle, P. (eds): Advances in X-Ray CT for Geomaterials. 2nd International Workshop GeoX.ISTE Ltd. (London): 35–53; 453 pp. http://onlinelibrary.wiley.com/doi/10.1002/9780470612187.ch2/summary Google Scholar
Boisson, J.Y., 2005. Clay club catalogue of characteristics of argillaceous rocks. Report NEA No. 4436. OECD/NEA (Paris), 72 pp. www.oecd-nea.org/rwm/reports/2005/nea4436-argillaceous-catalogue.pdf Google Scholar
Bruggeman, C., Maes, N., Aertsens, M. & De Cannière, P., 2009. Titrated water retention and migration behaviour in Boom Clay. SFC1 level 5 report (NIROND-TR 2009-16E), ONDRAF/NIRAS (Brussels, Belgium).Google Scholar
Bugani, S., Modugno, F., Łucejko, J.J., Giachi, G., Cagno, S., Cloetens, P., Janssens, K. & Morselli, L., 2009. Study on the impregnation of archaeological waterlogged wood with consolidation treatments using synchrotron radiation microtomography. Analytical and Bioanalytical Chemistry 395: 1977–1985. http://link.springer.com/article/10.1007%2Fs00216-009-3101-5 CrossRefGoogle Scholar
Cerepi, A., Durand, C. & Brosse, E., 2002. Pore microgeometry analysis in low-resistivity sandstone reservoirs. Journal of Petroleum Science and Engineering 35: 205-232. www.sciencedirect.com/science/article/pii/S0920410502002449 CrossRefGoogle Scholar
Clauset, A., Shalizi, C.R. & Newman, M.E.J., 2009. Power-law distributions in empirical data. SIAM Review 51: 661–703. http://arxiv.org/abs/0706.1062 CrossRefGoogle Scholar
Cnudde, V., Dewanckele, J., Boone, M., De Kock, T., Boone, M., Brabant, L., Dusar, M., De Ceukelaire, M., De Clerq, H., Hayen, R. & Jacobs, P., 2011. High-resolution X-ray CT for 3D petrography of ferruginous sandstone for an investigation of building stone decay. Microscopy Research and Technique 74: 1006–1017. www.ncbi.nlm.nih.gov/pubmed/21381150 Google Scholar
De Craen, M., Swennen, R., Keppens, E., Macaulay, C.I. & Kiriakoulakis, K., 1999. Bacterially mediated formation of carbonate concretions in the Oligocene Boom Clay of northern Belgium. Journal of Sedimentary Research 69: 1098–1106. http://archives.datapages.com/data/sepm/journals/v66-67/data/069/069005/1098.HTM?doi=10.1306%2FD4268B17-2B26-11D7-8648000102C1865D CrossRefGoogle Scholar
De Craen, M., Delleuze, D., Volckaert, G., Sneyers, A. & Put, M., 2000. The Boom Clay as natural analogue. SCK-CEN Final report to NIRAS/ONDRAF (1997-1999) R-3444. Waste & Disposal Department SCK-CEN (Mol, Belgium), 131 pp.Google Scholar
De Craen, M., Wang, L., Van Geet, M. & Moors, H., 2004. Geochemistry of Boom Clay pore water at the Mol site. SCK-CEN scientific report BLG-990. Waste & Disposal Department SCK-CEN (Mol, Belgium), 181 pp.Google Scholar
Decleer, J., Viane, W. & Vandenberghe, N., 1983. Relationships between chemical, physical and mineralogical characteristics of the Rupelian Boom Clay Belgium. Clay Minerals 18: 1–10. www.minersoc.org/pages/Archive-CM/Volume_18/18-1-1.htm CrossRefGoogle Scholar
Decleer, J. & Viaene, W., 1993. Rupelian Boom Clay as raw material for expanded clay manufacturing. Applied Clay Science 8: 111–128. www.sciencedirect.com/science/article/pii/016913179390032V CrossRefGoogle Scholar
Dehandschutter, B., Gaviglio, P., Sizun, J.P., Sintubin, M., Vandycke, S., Vandenberghe, N. & Wouters, L., 2005. Volumetric matrix strain related to intraformational faulting in argillaceous sediments. Journal of the Geological Society (London) 162: 801–813. http://jgs.geoscienceworld.org/content/162/5/801.full Google Scholar
Desbois, G., Urai, J. & Kukla, P.A., 2009. Morphology of the pore space in claystones – evidence from BIB/FIB ion beam sectioning and cryo-sem observations. eEarth 4: 15–22. www.electronic-earth-discuss.net/4/1/2009/eed-4-1-2009.html CrossRefGoogle Scholar
Desbois, G., Urai, J.L., Houben, M.E. & Sholokhova, Y., 2010a. Typology, morphology and connectivity of pore space in claystones from reference site for research using BIB, FIB and cryo-SEM methods. EPJ Web of Conferences (European Physical Journal) 6: 22005. www.epj-conferences.org/index.php?option=com_article&access=standard&Itemid=129&url=/articles/epjconf/abs/2010/05/epjconf_ICEM14_22005/epjconf_ICEM14_22005.html Google Scholar
Desbois, G., Enzmann, F., Urai, J.L., Baerle, C., Kukla, P.A. & Konstanty, J., 2010b. Imaging pore space in tight gas sandstone reservoir: Insights from broad ion beam cross-sectioning. EPJ Web of Conferences (European Physical Journal) 6: 22022. www.epj-conferences.org/index.php?option=com_article&access=standard&Itemid=129&url=/articles/epjconf/abs/2010/05/epjconf_ICEM14_22022/epjconf_ICEM14_22022.html CrossRefGoogle Scholar
Desbois, G., Urai, J.L., Kukla, P.A., Konstanty, J. & Baerle, C., 2011a. Highresolution 3D fabric and porosity model in a tight gas sandstone reservoir: A new approach to investigate microstructures from mm- to nm-scale combining argon beam cross-sectioning and SEM imaging. Journal of Petroleum Sciences and Engineering 78: 243–257. www.sciencedirect.com/science/article/pii/S0920410511001306 CrossRefGoogle Scholar
Desbois, G., Urai, J., Houben, M., Hemes, S. & Klaver, J., 2011b. BIB-SEM of representative area clay structures: Insights and challenges. NEA Clay Club Workshop Proceedings – Clay Under Nano- to Microscopic resolution – NEA OECD, 09 6-8, 2011 (Karlsruhe).Google Scholar
Desbois, G., Urai, J., Kukla, P., Wollenberg, U., Pérez-Willard, F., Radí, Z. & Riholm, S., 2012. Distribution of brine in grain boundaries during static recrystallization in wet, synthetic halite: Insight from broad ion beam sectioning and SEM observation at cryogenic temperature. Contributions to Mineralogy and Petrology 163: 19–31. http://link.springer.com/article/10.1007%2Fs00410-011-0656-x CrossRefGoogle Scholar
Desbois, G., Urai, J.L., Pérez-Willard, F., Radi, Z., Offern, S., Burkart, I., Kukla, P.A. & Wollenberg, U., 2013. Argon broad ion beam tomography in a cryogenic scanning electron microscope: A novel tool for the investigation of representative microstructures in sedimentary rocks containing pore fluid. Journal of Microscopy 249 (3): 215–235. http://onlinelibrary.wiley.com/doi/10.1111/jmi.12011/abstract Google Scholar
Diamond, S., 1970. Pore size distributions in clays. Clays and Clay Minerals 18: 7–23. http://clays.org/journal/archive/volume%2018/18-1-7.pdf CrossRefGoogle Scholar
Diamond, S., 2000. Mercury porosimetry an inappropriate method for the measurement of pore size distributions in cement-based materials. Cement and Concrete Composites 30: 1517–1525. www.sciencedirect.com/science/article/pii/S0008884600003707 Google Scholar
ESRI, 2011. ArcGIS Desktop: Release 10. Environmental Systems Research Institute (Redlands, CA).Google Scholar
Fadeev, A.Y., Borisova, O.R. & Lisichkin, G.V., 1996. Fractality of porous silicas: A comparison of adsorption and porosimetry data. Journal of Colloid and Interface Science 183: 1–5. www.sciencedirect.com/science/article/pii/S0021979796905111 Google Scholar
Friesen, W.I. & Mikula, R.J., 1987. Fractal dimensions of coal particles. Journal of Colloid and Interface Science 120: 263–271. www.sciencedirect.com/science/article/pii/0021979787903481 Google Scholar
FUNMIG – Fundamental processes of radionuclide migration, 2008. PID 3.2.1 Physical, mineralogical and geochemical characterization of the Boom Clay, Callovo-Oxfordian and Opalinus Clay rock samples, Contract No. FP6-516-514, 138 pp.Google Scholar
Gens, R., Lalieux, P., De Preter, P., Dierckx, A., Bel, J., Boyazis, J.P. & Cool, W., 2003. The Second Safety Assessment and Feasibility Interim Report (SAFIR 2) on HLW Disposal in Boom Clay: Overview of the Belgian Programme. MRS Proceedings, 807, 917 (Belgium). http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8008166 Google Scholar
Goldstein, M.L., Morris, S.A. & Yenj, G.G., 2004. Problems with fitting to the power-law distribution. European Physical Journal B 41: 255–258. http://link.springer.com/article/10.1140%2Fepjb%2Fe2004-00316-5 Google Scholar
Griffault, L., Merceron, T., Mossmann, J.R., Neerdael, B., De Cannière, P., Beacucaire, C., Daumas, S., Bianchi, A. & Christen, R., 1996. Participation to the project archimede-argile. EEC Contract No. FI2W-CT90-0117, final report EUR 17454, ANDRA (France).Google Scholar
Heath, J.E., Dewers, T.A., McPherson, B.J.O.L., Petrusak, R., Chidsey, T.C., Rinehart, A.J. & Mozley, P.S., 2011. Pore networks in continental and marine mudstones: Characteristics and controls on sealing behavior. Geosphere 7: 429–454. http://geosphere.gsapubs.org/content/7/2/429.abstract Google Scholar
Hildenbrand, A. & Urai, J.L., 2003. Investigation of the morphology of pore space in mudstones – first results. Marine and Petroleum Geology 20: 1185–1200. www.sciencedirect.com/science/article/pii/S0264817203000904 Google Scholar
Holzer, L., Münch, B., Wegmann, M. & Gasser, P., 2006. FIB-nanotomography of particulate systems – part I: Particle shape and topology of interfaces. Journal of the American ceramic society 89: 2577–2585. http://onlinelibrary.wiley.com/doi/10.1111/j.1551-2916.2006.00974.x/abstract CrossRefGoogle Scholar
Holzer, L., Gasser, P., Kaech, A., Wegmann, M., Zingg, A., Wepf, R. & Münch, B., 2007. Cryo-FIB-nanotomography for quantitative analysis of particle structures in cement suspension. Journal of Microscopy 227: 216–228. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2818.2007.01804.x/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false Google Scholar
Holzer, L., Münch, B., Rizzi, M., Wepf, R., Marschall, P. & Graule, T., 2010. 3D-microstructure analysis of hydrated bentonite with cryo-stabilized pore water. Applied Clay Science 47: 330–342. www.sciencedirect.com/science/article/pii/S016913170900341X Google Scholar
Holzer, L. & Cantoni, M., 2012. Review of FIB-tomography. In: Utke, I., Moshkalev, S. & Russell, P. (eds): Nanofabrication using focused ion and electron beams: Principles and applications. Oxford University Press (New York), 813 pp.Google Scholar
Honty, M., De Craen, M., Wang, L., Madejová, J., Czímerová, A., Pentrák, M., Stríček, I. & Van Geet, M., 2010. The effect of high ph alkaline solutions on the mineral stability of the Boom Clay – batch experiments at 60° C. Applied Geochemistry 25: 825–840. www.sciencedirect.com/science/article/pii/S0883292710000739 Google Scholar
Horseman, S.T., Higgo, J.J.W., Alexander, J. & Harrington, J.F., 1996. Water, gas and solute movement through argillaceous media. The NEA (Nuclear Energy Agency) Working Group on Measurement and Physical Understanding of Groundwater Flow Through Argillaceous Media (‘Clay Club’), a subgroup of the NEA Co-ordinating Group on Site Evaluation and Design of Experiments for Radioactive Waste Disposal (SEDE), Report 96/1 OECD, Paris, 290 pp.Google Scholar
Houben, M.E., Desbois, G. & Urai, J.L., 2013. Pore morphology and distribution in the shaly facies of Opalinus Clay (Mont Terri, Switzerland): Insights from representative 2D BIB-SEM investigations on mm to nm scale. Applied Clay Science 71: 82–97. www.sciencedirect.com/science/article/pii/S0169131712002980 Google Scholar
Jackson, M.L., 1985. Soil chemical analysis – advanced course, revised 2nd edition, 11th printing. Parallel Press, University of Wisconsin – Madison Libraries (Madison, Wisconsin), 895 pp.Google Scholar
Janssen, C., Wirth, R., Reinicke, A., Rybacki, E., Naumann, R., Wenk, H.R. & Dresen, G., 2011. Nanoscale porosity in SAFOD core samples (San Andreas Fault). Earth and Planetary Science Letters 301: 179–189. www.sciencedirect.com/science/article/pii/S0012821X1000693X Google Scholar
Jin, G., 2007. Experimental validation of pore-level calculations of static and dynamic petrophysical properties of clastic rock. Society of Petroleum Engineers, 109547-MS. SPE International Annual Technical Conference and Exhibition, 11. 11-14, 2007 (Anaheim, California, U.S.A), 13 pp. www.onepetro.org/mslib/app/Preview.do?paperNumber=SPE-109547-MS&societyCode=SPE Google Scholar
Johnston, D.D. & Johnson, R.J., 1987. Depositional and diagenetic controls on reservoir quality in first Wilcox Sandstone, Livingston Field Louisiana. American Association of Petroleum Geologists 71: 1152–1161. http://archives.datapages.com/data/bulletns/1986-87/data/pg/0071/0010/1150/1152.htm Google Scholar
Kameda, A., Dvorkin, J., Keehm, Y., Nur, A. & Bosl, W., 2006. Permeability-porosity transforms from small sandstone fragments. Geophysics 71: N11–N19. www.intl-geophysics.geoscienceworld.org/content/71/1/N11.full CrossRefGoogle Scholar
Keller, L.M., Holzer, L., Wepf, R. & Gasser, P., 2011. 3D geometry and topology of pore pathways in Opalinus Clay: Implications for mass transport. Applied Clay Science 52: 85–95. www.sciencedirect.com/science/article/pii/S0169131711000573 Google Scholar
Kemball, C., 1946. On the surface tension of Mercury. Transactions of the Faraday Society 42: 526–537. http://pubs.rsc.org/en/content/articlepdf/1946/tf/tf9464200526 Google Scholar
Klaver, J., Desbois, G., Urai, J.L. & Littke, R., 2012. BIB-SEM study of the pore space morphology in early mature Posidonia Shale from the Hils Area Germany. International Journal of Coal Geology 103: 12–25. www.sciencedirect.com/science/article/pii/S0166516212001747 Google Scholar
Klinkenberg, M., Kaufhold, S., Dohrmann, R. & Siegesmund, S., 2009. Influence of carbonate microfabrics on the failure strength of claystones. Engineering Geology 107: 42–54. www.sciencedirect.com/science/article/pii/S001379520900101X CrossRefGoogle Scholar
Kolor, , 2012. Autopano Giga 2.6.1 (Challes-les Eaux, France).Google Scholar
Korvin, G., 1992. Fractal models in the earth sciences. Elsevier (Amsterdam), 396 pp.Google Scholar
Laenen, B., 1997. The geochemical signature of relative sea-level cycles recognized in the Boom Clay (PhD-thesis). Katholieke Universiteit Leuven, Faculteit Wetenschappen, Departement Geografie – Geologie (Leuven, Belgium), 396 pp.Google Scholar
Lexa, O., Štípská, P., Schulmann, K., Baratoux, L. & Kröner, A., 2005. Contrasting textural record of two distinct metamorphic events of similar p-T conditions and different durations. Journal of Metamorphic Geology 23: 649–666. http://onlinelibrary.wiley.com/doi/10.1111/j.1525-1314.2005.00601.x/abstract CrossRefGoogle Scholar
Loucks, R.G., Reed, R.M., Ruppel, S.C. & Jarvie, D.M., 2009. Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett Shale. Journal of Sedimentary Research 79: 848–861. http://jsedres.sepmonline.org/content/79/12/848.abstract Google Scholar
Loucks, R.G., Reed, R.M., Ruppel, S.C. & Hammes, U., 2012. Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores. AAPG Bulletin 96: 1071–1098. http://aapgbull.geoscienceworld.org/content/96/6/1071.abstract Google Scholar
MATLAB, 2011. Version 7.12.0.635 (R2011a). The MathWorks Inc. (Natick, Massachusetts U.S.A).Google Scholar
Mandelbrot, B., 1982. The fractal geometry of nature. W.H. Freeman (New York), 468 pp.Google Scholar
Matthews, G.P., Ridgway, C.J. & Spearing, M.C., 1995. Void space modeling of Mercury intrusion hysteresis in sandstone, paper coating, and other porous media. Journal of Colloid and Interface Science 171: 8–27. www.sciencedirect.com/science/article/pii/S0021979785711460 Google Scholar
Merceron, T., 1994. Characterisation of the geochemical environment of the Boom Clay at Mol. Archimedes – clay project, Proceedings MIRAGE meeting on the Migration of Radionuclides in the Geosphere, 3rd Phase, 11. 15-17, 1994 (Brussels, Belgium).Google Scholar
Meyer, K., Lorenz, P., Böhl-Kuhn, B. & Klobes, P., 1994. Porous solids and their characterization methods of investigation and application. Crystal Research and Technology 29: 903–930. http://onlinelibrary.wiley.com/doi/10.1002/crat.2170290702/abstract Google Scholar
Moro, F. & Böhni, H., 2002. Ink-bottle effect in Mercury intrusion Porosimetry of cement-based materials. Journal of Colloid and Interface Science 246: 135–149. www.sciencedirect.com/science/article/pii/S0021979701979627 Google Scholar
Neuzil, C.E., 1994. How permeable are clays and shales? Water Resource Ressearch 30: 145-150. http://onlinelibrary.wiley.com/doi/10.1029/93WR02930/abstract Google Scholar
Newman, M.E.J., 2006. Power laws, pareto distributions and zipf's law. Contemporary Physics 46: 323–351. http://arxiv.org/abs/cond-mat/0412004 CrossRefGoogle Scholar
Nicholas, M.E., Joyner, P.A., Tessem, B.M. & Olson, M.D., 1961. The effect of various gases and vapors on the surface tension of Mercury. The Journal of Physical Chemistry 65: 1373–1375. http://pubs.acs.org/doi/abs/10.1021/j100826a023 Google Scholar
ONDRAF/NIRAS, 2011. Waste plan for the long-term management of conditioned high-level and/or long-lived radioactive waste and overview of related issues. Report NIROND 2011-02 E; Belgium, 255 pp. www.ondraf-plandechets.be/nieuw/downloads/Waste%20plan%20-%20English.pdf Google Scholar
Ortiz, L., Volckaert, G. & Mallants, D., 2002. Gas generation and migration in Boom Clay, a potential host rock formation for nuclear waste storage. Engineering Geology 64: 287–296. www.sciencedirect.com/science/article/pii/S0013795201001077 Google Scholar
Pareto, V., 1896–1897. Cours d'économie politique. Rouge F. (Lausanne) & Pichon, F. (Paris), Vol. I-II: 430; 426 pp.Google Scholar
Penumadu, D. & Dean, J., 2000. Compressibility effect in evaluating the pore-size distribution of kaolin clay using mercury intrusion porosimetry. Canadian Geotechnical Journal 37 (2): 393–405. www.nrcresearchpress.com/doi/abs/10.1139/t99-121#.Uh73jj_kwxw Google Scholar
Romero, E., Gens, A. & Lloret, A., 1999. Water permeability, water retention and microstructure of unsaturated compacted Boom Clay. Engineering Geology 54: 117–127. www.sciencedirect.com/science/article/pii/S0013795299000678 Google Scholar
Romero, E. & Simms, P., 2008. Microstructure investigation in unsaturated soils: A review with special attention to contribution of Mercury intrusion Porosimetry and environmental scanning electron microscopy. Geotechnical and Geological Engineering 26: 705–727. http://link.springer.com/article/10.1007%2Fs10706-008-9204-5?LI=true Google Scholar
Ruffett, C., Gueguen, Y. & Darot, M., 1991. Complex conductivity measurements and fractal nature of porosity. Geophysics 56: 758–768. http://geophysics.geoscienceworld.org/content/56/6/758.abstract Google Scholar
Schmidt, V. & McDonald, D.A., 1979. The role of secondary porosity in the course of sandstone diagenesis. SEPM Special Publications (Aspects of diagenesis) 26: 175-207. http://archives.datapages.com/data/sepm_sp/SP26/The_Role_of_Secondary_Porosity.html Google Scholar
Sigal, R.F., 2009. A methodology for blank and conformance corrections for high pressure Mercury Porosimetry. Measurement Science and Technology 20, 11 pp. http://iopscience.iop.org/0957-0233/20/4/045108 Google Scholar
Sok, R.M., Varslot, T., Ghous, A., Latham, S., Sheppard, A.P. & Knackstedt, M.A., 2009. Pore scale characterization of carbonates at multiple scales: Integration of micro-CT and FIB-SEM. International Symposium of the Society of Core Analysts, 09., 27-30, 2009 (Noordwijk, the Netherlands), 12 pp. www.scaweb.org/assets/papers/2009_papers/SCA2009-18.pdf Google Scholar
Turcotte, D.L., 1997. Fractals and chaos in geology and geophysics, 2nd edition. Cambridge University Press (Cambridge, UK): 398 pp.Google Scholar
Urai, J.L., Nover, G., Zwach, C., Ondrak, R., Schöner, R. & Kroos, B.M., 2008. Transport processes. Dynamics of complex intracontinental basins: The central european basin system. Springer, Berlin-Heidelberg: 367–388.Google Scholar
Van Geet, M., Bastiaens, W. & Ortiz, L., 2008. Self-sealing capacity of argillaceous rocks: Review of laboratory results obtained from the SELFRAC project. Physics and Chemistry of the Earth 33: S396–S406. www.sciencedirect.com/science/article/pii/S1474706508002891 Google Scholar
Vandenberghe, N., 1974. Een sedimentologische studie van de Boomse klei, doctorale verhandeling/Unpublished PhD thesis, Catholic University (K.U.) Leuven, 187 pp.Google Scholar
Vandenberghe, N., 1978. Sedimentology of the Boom Clay (Rupelian) in Belgium. Verhandeling Koninklijke Academie voor Wetenschappen, Letteren en Schone Kunsten van België, Klasse Wetenschappen XL/147. Paleis der Academien (Brussels, Belgium), 137 pp.Google Scholar
Verhoef, E. & Schröder, T., 2011. Research Plan. OPERA-PG-COV004. COVRA N.V. (the Netherlands), 52 pp.Google Scholar
Verhoef, E., Neeft, E., Grupa, J. & Poley, A., 2011. Outline of a disposal in clay. OPERA-PG-COV008. COVRA N.V. (the Netherlands), 23 pp.Google Scholar
Washburn, E.W., 1921. The dynamics of capillary flow. Physical Review 17: 273. http://prola.aps.org/abstract/PR/v17/i3/p273_1 Google Scholar
Webb, P.A., 2001. An introduction to the physical characterization of materials by Mercury intrusion Porosimetry with emphasis on reduction and presentation of experimental data. Micromeritics Instrument Corporation (Norcross, Georgia, USA): 23 pp. www.micromeritics.com/Repository/Files/mercury_paper.pdf Google Scholar
Wentworth, C.K., 1922. A scale of grade and class terms for clastic sediments. The Journal of Geology 30: 377–392. www.jstor.org/stable/30063207 Google Scholar
Wilson, J.C. & McBride, E.F., 1988. Compaction and porosity evolution of Pliocene sandstones, Ventura Basin California. American Association of Petroleum Geologists 72: 664–681. http://archives.datapages.com/data/bulletns/1988-89/data/pg/0072/0006/0650/0664.htm?doi=10.1306%2F703C8EFC-1707-11D7-8645000102C1865D Google Scholar
Wouters, L., Herron, M., Abeels, V., Hagood, M. & Strobel, J., 1999. Innovative applications of dual range fourier transform infrared spectroscopy to analysis of Boom Clay mineralogy. Aardkundige Mededelingen 9: 159–168.Google Scholar
Zeelmaekers, E., 2011. Computerized qualitative and quantitative clay mineralogy: Introduction and application to known geological cases. Unpublished PhD thesis, Katholieke Universiteit (K.U.) Leuven. Groep Wetenschap en Technologie (Heverlee, Leuven), 397 pp.Google Scholar
Zipf, G.K., 1949. Human behaviour and the principle of least effort – an introduction to human ecology. Addison-Wesley Press (Oxford) England, 573 pp.Google Scholar