Multi-scale pore structure of COx claystone: Towards the prediction of fluid transport

Song, Yulong; Davy, Catherine; Tománek, David; Blanchenet, Anne-Marie; Skoczylas, Frédéric; Talandier, Jean; Robinet, Jean-Charles

doi:10.1016/j.marpetgeo.2015.04.004

Cited by 58 publications

(56 citation statements)

References 68 publications

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“…For FIB/SEM, the direction perpendicular to imaging is z (it is the direction for slicing the sample at 10 to 20 nm thickness), whereas each image is in a (x, y) plane. Full details on the procedures are given in [11,12]. The main properties of the samples are gathered in Tables 1 and 2.…”

Section: Methodsmentioning

confidence: 99%

“…Their pores are mainly located within their clay matrix or at its interface with non porous minerals [3-6, 10, 14]. The clay pores, of 1-100 nm size 1 , most likely dominate the flow and transport properties [5,11,12]. Moreover, during sedimentation and compaction, clay minerals are deposited along preferred orientations, i.e.…”

Section: Scientific Contextmentioning

confidence: 99%

“…We also combine both FIB/SEM and TEM imaging of the mesoscopic clay matrix to describe the smallest 1-100nm pores. Four percolating FIB/SEM samples (27.8-146.7μm 3 ), and up to eight TEM images (18.5x10 3 -41.0x10 3 nm 2 ) are used, which are fully analyzed in previous research [11,12].…”

Section: Scientific Contextmentioning

confidence: 99%

“…It is performed on synthetic 3D images, obtained by the direct sampling method [13] on actual micro-tomography images of the same shale as in [11]. The medium is composed of three phases.…”

Section: Permeability At the Macroscopic Scalementioning

confidence: 99%

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Understanding fluid transport through the multiscale pore network of a natural shale

et al. 2017

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Abstract. The pore structure of a natural shale is obtained by three imaging means. Micro-tomography results are extended to provide the spatial arrangement of the minerals and pores present at a voxel size of 700 nm (the macroscopic scale). FIB/SEM provides a 3D representation of the porous clay matrix on the so-called mesoscopic scale (10-20 nm); a connected pore network, devoid of cracks, is obtained for two samples out of five, while the pore network is connected through cracks for two other samples out of five. Transmission Electron Microscopy (TEM) is used to visualize the pore space with a typical pixel size of less than 1 nm and a porosity ranging from 0.12 to 0.25. On this scale, in the absence of 3D images, the pore structure is reconstructed by using a classical technique, which is based on truncated Gaussian fields. Permeability calculations are performed with the Lattice Boltzmann Method on the nanoscale, on the mesoscale, and on the combination of the two. Upscaling is finally done (by a finite volume approach) on the bigger macroscopic scale. Calculations show that, in the absence of cracks, the contribution of the nanoscale pore structure on the overall permeability is similar to that of the mesoscale. Complementarily, the macroscopic permeability is measured on a centimetric sample with a neutral fluid (ethanol). The upscaled permeability on the macroscopic scale is in good agreement with the experimental results.

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Section: Methodsmentioning

confidence: 99%

Section: Scientific Contextmentioning

confidence: 99%

Section: Scientific Contextmentioning

confidence: 99%

“…It is performed on synthetic 3D images, obtained by the direct sampling method [13] on actual micro-tomography images of the same shale as in [11]. The medium is composed of three phases.…”

Section: Permeability At the Macroscopic Scalementioning

confidence: 99%

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Understanding fluid transport through the multiscale pore network of a natural shale

et al. 2017

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“…Performed investigations to characterize this porosity indicate that pore network is composed mainly of meso/micro pores and shows a very low connectivity for pores over 40 nm [8]. Using various imaging techniques such as electron microscopy or Xray tomography mineral maps have been obtained [9] highlighting a preferential orientation parallel to the bedding of carbonate and tectosilicates inclusions ( Figure 1). Nevertheless, orientation of clay particles and aggregates with the bedding plan is not too marked as it could be found in other indurated clays such as Opalinus Clay in Switzerland.…”

Section: Microstructurementioning

confidence: 99%

Inputs from in situ experiments to the understanding of the unsaturated behaviour of Callovo-Oxfordian claystone

Armand¹,

Djizanne²,

Zghondi³

et al. 2016

E3S Web Conf.

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Abstract. The French national radioactive waste management agency (Andra) research program is dedicated to preparing the construction and operation of a deep geological disposal facility for high-level and intermediate-level long-lived radioactive waste (HL, IL-LLW) in the Callovo-Oxfordian claystone (COx). The characterization of the COx thermo-hydro-mechanical (THM) behavior, at different scales of interest, must gradually give relevant data for design and safety calculations. The effects of saturation and desaturation of COx claystone are studied in laboratory conditions (sample scale) and in situ (drift scale), in order to improve knowledge on ventilation effect at gallery wall as galleries will remains open during operational phase (more than 100 years for some specific galleries) in the repository. The Saturation Damaged Zone (SDZ) experiment is outlined and its results are discussed. This experimentation aims to change the relative humidity in an isolated portion of a gallery in order to follow the HM behavior of the surrounding rock mass. Drying and wetting cycles could induce in certain cases cracks and swelling and modify the hydromechanical behavior of the claystone around the gallery (Young modulus, strength, creep…). The long term behavior of the COx claystone at the vicinity of gallery is then studied by performing climatic, hydraulic, geological and geomechanical measurements. Results of the in situ experiment are discussed with respect to the identified process on samples. The discussion given on this paper intends to highlights the inputs from 7 years of an in situ experiment to better understand the unsaturated behavior of the COx claystone.

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Numerical prediction of gas migration properties in Callovo‐Oxfordian (COx) argillite using morpho‐mathematical operations

Zhang

Duveau

Colliat

2018

Num Anal Meth Geomechanics

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Summary The feasibility study of long‐term radioactive waste storage in low‐permeable rocks has been performed by considering various damage and failure scenarios. This study aims at the numerical investigation of gas (mainly produced by corrosion of metallic parts) migration properties through the low‐permeable formation of Callovo‐Oxfordian argillite. Traditional methods, based on macroscopic approaches or homogeneous transport properties, are inappropriate to analyze this issue at the mesoscopic/microscopic scale. In this study, realistic porous space morphologies are constructed through union of excursions of random fields considering different experimental pore size distributions. Afterwards, purely geometric analysis of pore space is conducted by morpho‐mathematical operations for the purpose of the extraction of preferential gas transport pathways and the prediction of the gas entry pressure, the gas breakthrough pressure, and the following imbibition process.

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Multi-scale pore structure of COx claystone: Towards the prediction of fluid transport

Cited by 58 publications

References 68 publications

Understanding fluid transport through the multiscale pore network of a natural shale

Understanding fluid transport through the multiscale pore network of a natural shale

Inputs from in situ experiments to the understanding of the unsaturated behaviour of Callovo-Oxfordian claystone

Numerical prediction of gas migration properties in Callovo‐Oxfordian (COx) argillite using morpho‐mathematical operations

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