A new hollow cylinder triaxial cell to study the behavior of geo-materials with low permeability

Monfared, Mohammad; Delage, Pierre; Sulem, Jean; Mohajerani, Mehrdokht; Tang, Anh Minh; Laure, Emmanuel De

doi:10.1016/j.ijrmms.2011.02.017

Cited by 51 publications

(50 citation statements)

References 23 publications

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“…The device includes a specially designed system of displacement transducers (LVDT) to measure local radial and axial strains (three LVDTs for radial measurement and two LVDTs for axial measurements -1 μm precision manufactured by Solartron -see details in Monfared et al 2011). …”

Section: Strain Measurementmentioning

confidence: 99%

Measurement and modeling of adsorptive–poromechanical properties of bituminous coal cores exposed to CO2: Adsorption, swelling strains, swelling stresses and impact on fracture permeability

Espinoza

Vandamme

Pereira

et al. 2014

International Journal of Coal Geology

102

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International audienceThe reservoir response of unmineable coal seams to primary and enhanced natural gas recovery is strongly affected by gas sorption and the swelling properties of the coal reservoir rock. In-depth understanding of the process of gas sorption/desorption in the coal matrix, induced deformation and measurement of relevant physical parameters are critical for predictive reservoir management. Models used in industry practice are based on swelling strains measured in “free” swelling coal or on empirical correlations between strain and adsorption, and predict permeability changes based on changes of porosity or stress calculated assuming an analogy with thermoelasticity. However, not only coal seams are subjected to in-situ stresses and geometrical boundary conditions but also sorption and strain are strongly coupled. Representative experiments and a truly coupled model for coal seams are needed in challenging applications. We present a set of triaxial testing measurements on 38 mm diameter fractured sub-bituminous/bituminous coal cores exposed to CO2. Testing includes the measurement of fluid uptake, adsorption-induced strains and stresses, and the impact on simultaneously measured permeability. Noteworthy, we measured increases in effective stress of up to 29 MPa when injecting CO2 at 5 MPa and preventing the coal core to swell. The results are analyzed with a poromechanical model in which coal matrix microporosity and adsorption-induced phenomena are embedded into a fractured reservoir rock with transverse isotropic properties. The adsorptive–mechanical coupling in the coal matrix is integrated through an adsorption stress function and fractured coal permeability is estimated as a function of Terzaghi's effective stresses (parallel and perpendicular to the bedding plane). The experimental results and model predictions help identify the characteristic response of coal microporosity and cleat macroporosity on the poromechanical response of coal cores, and suggest that order of magnitude changes of reservoir permeability observed in the field are linked to sorption-induced change on Terzaghi's effective horizontal stress under laterally constrained displacement condition. Together, the modeling and experimental characterization offer unprecedented insights into the mechanics of coal

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Section: Strain Measurementmentioning

confidence: 99%

Measurement and modeling of adsorptive–poromechanical properties of bituminous coal cores exposed to CO2: Adsorption, swelling strains, swelling stresses and impact on fracture permeability

Espinoza

Vandamme

Pereira

et al. 2014

International Journal of Coal Geology

102

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“…This can be made either by testing small specimens or by adopting specimen shapes with reduced drainage length. 11,14,15 These aspects will be commented in more details later.…”

Section: Introductionmentioning

confidence: 99%

The thermo-mechanical behaviour of the Callovo-Oxfordian claystone

Menaceur

Delage

Tang

et al. 2015

International Journal of Rock Mechanics and Mining Sciences

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International audienceThe Callovo-Oxfordian (COx) claystone is considered as a potential host rock in the French concept of high level radioactive waste disposal at great depth. To better understand and to complement existing published data on the thermo-hydro-mechanical behaviour of the COx claystone, an experimental program was carried out using a hollow cylinder triaxial device specially developed for low permeability materials. Special care was devoted to the saturation of the specimens that was made under stress conditions close to in-situ, and to conditions ensuring full drainage thanks to a reduced drainage length and low shear rate. Tests were carried out under in-situ, half to in-situ and twice the Terzaghi mean effective in-situ stress at 25 °C and 80 °C to investigate the effects in the close field of the temperature elevation due to the exothermic nature of the waste. Some radial permeability tests were also conducted at various temperatures. The data obtained showed that there is little effect of temperature on the elastic parameters determined, whereas a tendency to a decrease in shear strength was noted, in accordance with the few available published data. Temperature also appeared to have little effect on the intrinsic permeability, with higher flows mainly due to the decrease in water viscosity. & 2015 Published by Elsevier Ltd

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“…Revil and Lu,18). By only considering capillary effects, the suction s exerted when desaturating 32 nm diameter pores is given by the Young-Laplace equation: (1) in which  w/a is the water/air interfacial tension equal to COx claystone, confirming the predominance of capillary effects in the clay water interaction in these inter-platelets pores schematically represented in Figure 3. Comparing this value with the final suction of 21 MPa finally measured in the sample indicates that interplatelets pores have been desaturated.…”

Section: Discussionmentioning

confidence: 80%

“…In low permeability rocks (the saturated permeability is in the order of 10 -13 m/s in the COx claystone), saturation can be quite long and pore pressure homogeneity during testing can be problematic. In this regards, specific devices with reduced length of drainage have been developed (Monfared et al,1,Hu et al,2).…”

Section: Introductionmentioning

confidence: 99%

Stress release and suction generation in the Callovo-Oxfordian claystone

et al. 2016

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Abstract. Stress release effects in a specimen of claystone extracted at great depth (465 m) in the layer of the Callovo-Oxfordian claystone in Eastern France is examined by mimicking the stress change during extraction in the oedometer. To do so, a specimen first submitted to hydration with swelling impeded is afterwards unloaded at constant water content. Comparable mercury intrusion pore size distribution curves are obtained before and after stress release, showing little change in the configuration of inter-platelets pores within the clay matrix of the claystone. The swelling observed at constant water content is then related, to a water transfer from inter-platelets pores to intra-platelets pores, resulting in crystalline swelling within the smectite fraction of the inter-layer illitesmectite minerals.

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A new hollow cylinder triaxial cell to study the behavior of geo-materials with low permeability

Cited by 51 publications

References 23 publications

Measurement and modeling of adsorptive–poromechanical properties of bituminous coal cores exposed to CO2: Adsorption, swelling strains, swelling stresses and impact on fracture permeability

Measurement and modeling of adsorptive–poromechanical properties of bituminous coal cores exposed to CO2: Adsorption, swelling strains, swelling stresses and impact on fracture permeability

The thermo-mechanical behaviour of the Callovo-Oxfordian claystone

Stress release and suction generation in the Callovo-Oxfordian claystone

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