Geomechanical Characterization of Marcellus Shale

Lora, Rafael Villamor; Ghazanfari, Ehsan; Izquierdo, Enrique Asanza

doi:10.1007/s00603-016-0955-7

Cited by 61 publications

(17 citation statements)

References 48 publications

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“…In addition to the previously mentioned parameters (composition, E, σ TCS , and B), the angle between the maximum principal stress orientation and bedding orientation will also influence the primary creep strain due to the anisotropic character of shale rocks (Swan et al 1989;Villamor Lora et al 2016). If loaded parallel instead of perpendicular to bedding, samples would creep at slower rate yielding less creep strain after 3 years deformation (cf., Sone and Zoback 2014).…”

Section: Effect Of Sample Composition and Mechanical Propertiesmentioning

confidence: 99%

“…As the permeability of shales is very low (e.g., Naumann et al 2007;Holt et al 2012;Villamor Lora et al 2016), reservoir stimulation using hydraulic fracturing is needed to increase well productivity and allow economical exploitation (Li et al 2015). Commonly, proppants (quartz, bauxite ceramic) are added to the frac fluid to keep fractures open.…”

Section: Introductionmentioning

confidence: 99%

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Deformation Experiments on Bowland and Posidonia Shale—Part II: Creep Behavior at In Situ pc–T Conditions

et al. 2019

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To unravel their long-term creep properties at simulated reservoir conditions, we conducted constant stress deformation experiments at elevated confining pressures, p c = 50-115 MPa, and temperatures, T = 75-150 °C, on Posidonia (GER) and Bowland (UK) shale, which exhibit varying petrophysical and mechanical properties. Depending on applied p c-T conditions and sample composition, recorded creep curves exhibit either only a primary (decelerating) or additionally a secondary (quasi-steady state) and a tertiary (accelerating) creep phase during deformation. At high temperature and axial differential stress and low confining pressure, creep strain is enhanced and a transition from primary towards secondary and tertiary creep behavior is observable. Creep strain of Posidonia shale, which is rich in weak constituents (clay, mica, and organic content), is enhanced when compared to creep strain recorded during deformation of either carbonate-or quartz-rich Bowland shale. Electron microscopy observations revealed that creep strain is mainly accommodated by the deformation of weak minerals and local pore space reduction. In addition, microcrack growth occurred during secondary creep. An empirical correlation between creep strain and time based on a power law was used to describe the decelerating creep phase, also accounting for the influence of confining pressure, temperature, and axial differential stress. The results suggest that the primary creep strain can be correlated with mechanical properties determined from short-term constant strain rate experiments such as static Young's modulus and triaxial compressive strength.

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Section: Effect Of Sample Composition and Mechanical Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deformation Experiments on Bowland and Posidonia Shale—Part II: Creep Behavior at In Situ pc–T Conditions

et al. 2019

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“…The Total Organic Carbon (TOT) of the tested shale specimens yielded 2,6 % approximately. Villamor-Lora et al [31] carried out a detailed study of the anisotropic strain-stress relationships at several temperatures with similar specimens of this shale rock.…”

Section: Asaoka's Methodsmentioning

confidence: 99%

The use of hyperbolic and Asaoka’s methods to estimate the moisture diffusivity and the hydraulic conductivity of unsaturated soils from tests to determine the SWRC

2020

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The equation governing the unsaturated transient flow in a soil sample when subjected to suction (ψ) at its base and that of the classical 1-D consolidation are exactly alike (equation of diffusion). The former can be arrived at by Richards’ equation, being in this case the moisture diffusivity (D), instead of the coefficient of consolidation (cv), the governing parameter. D need not be constant, but rather a function of the volumetric water content, D=D(θ), and is defined as the ratio of the hydraulic conductivity, k(θ), over the specific water capacity, C(θ)=dθ/dψ, i.e., the slope of the SWRC. The hyperbolic method has been used for several geotechnical purposes and, most importantly, as an alternative to Asaoka’s method for predicting the final settlement and cv of soft soils undergoing consolidation, improved by preloading. This paper shows that both methods prove to be very useful as a means of obtaining D(θ) and k(θ) at a certain range of θ, provided that a reduced number of water contents at known elapsed times are determined over the medium stage of this transient flow. It is addressed in the paper both by theoretical grounds and on the light of experimental data of 4 soils.

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“…Steiger and Leung 1991, Schmitt et al 1994, Aoki 1995, Islam and Skalle 2013, the production of shale oil and gas (e.g. Ewy et al 2003, Eseme et al 2007, Villamor-Lora et al 2016, tunnelling issues (e.g. Einstein 2000, Bonini et al 2009, and CO2 sequestration (Busch et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Drained Triaxial Tests in Low-Permeability Shales: Application to the Callovo-Oxfordian Claystone

et al. 2018

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Drained triaxial testing is challenging in low permeability claystones (10-20 m 2). This paper presents a method of testing low permeability clay rocks in a standard triaxial cell. In this system, the resaturation of the specimen and the drainage conditions were enhanced by reducing the drainage length to 19 mm, the specimen radius. To do so, two geotextiles were placed around the top and bottom ends of the specimen, with no connection between them. Resaturation was hence performed by forcing water infiltration into the specimen from the upper and lower geotextiles, with a maximum infiltration length of around 19 mm, resulting in reasonable saturation durations. High precision local measurements of radial strains were also achieved by ensuring direct contact between the LVDT rod and the specimen through the membrane. A poroelastic numerical calculation was carried out, and it was shown that, with these drainage conditions, a strain rate of 6.6×10-8 s-1 was satisfactory to ensure good drainage when shearing claystone specimens. After a check test made on a low permeability sandstone with well-known mechanical characteristics, two tests were carried out to investigate specimens of the Callovo-Oxfordian claystone, a possible host rock for deep geological disposal in France. The results compare well with other published data from drained triaxial tests.

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Geomechanical Characterization of Marcellus Shale

Cited by 61 publications

References 48 publications

Deformation Experiments on Bowland and Posidonia Shale—Part II: Creep Behavior at In Situ pc–T Conditions

Deformation Experiments on Bowland and Posidonia Shale—Part II: Creep Behavior at In Situ pc–T Conditions

The use of hyperbolic and Asaoka’s methods to estimate the moisture diffusivity and the hydraulic conductivity of unsaturated soils from tests to determine the SWRC

Drained Triaxial Tests in Low-Permeability Shales: Application to the Callovo-Oxfordian Claystone

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