Large Rock Mass Experimentation @ Mont Terri Underground Research Laboratory – CO2 Containment Assurance Experiments

Goodman, Harvey; Imbus, Scott W.; Espie, Tony; Minnig, Christian; Rösli, Ursula; Fierz, T.; Lettry, Yanick

doi:10.1016/j.egypro.2017.03.1668

Cited by 5 publications

(4 citation statements)

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“…The exposure of Opalinus Clay in the laboratory galleries gives an excellent opportunity to investigate an unweathered clay fault system (Nussbaum et al 2011;Jaeggi et al 2017). The study of this formation is important because it is a potential host rock for deep nuclear waste disposal and a caprock analog for a geological carbon dioxide (CO 2 ) storage in deep geological reservoirs (Goodman et al 2017).…”

Section: Simfip Probementioning

confidence: 99%

In Situ Direct Displacement Information on Fault Reactivation During Fluid Injection

Kakurina

Guglielmi

Nussbaum³

et al. 2020

Rock Mech Rock Eng

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The three dimensional (3D) displacement induced by fluid injection was measured during two fault reactivation experiments conducted in carbonate rocks at the Rustrel Low Noise Underground Laboratory (LSBB URL), France, and in shale rocks at the Mont Terri Rock laboratory, Switzerland. The faults were activated by injecting high pressure fluid and using the Step-Rate Injection Method for Fracture In-Situ Properties, which allows a coupled pressure-flowrate-3D displacement monitoring in boreholes. Both experiments mainly show complex aseismic deformation of preexisting fractures that depend on (1) the fluid pressure variations related to chamber pressurization and leakage into the formation and (2) irreversible shear slip and opening of the reactivated fractures. Here we detail the processing of the 3D displacement data from both experiments to isolate slip vectors from the complex displacement signal. Firstly, we explain the test protocol and describe the in situ hydromechanical behavior of the borehole/fault system. Secondly, we define the methodology of the displacement data processing to isolate slip vectors with high displacement rates, which carry information about the key orientation of fault reactivation. Finally, we discuss which slip vectors can potentially be used to solve the stress inversion problem.

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Section: Simfip Probementioning

confidence: 99%

In Situ Direct Displacement Information on Fault Reactivation During Fluid Injection

Kakurina

Guglielmi

Nussbaum³

et al. 2020

Rock Mech Rock Eng

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“…In this study, we assess the self‐sealing response of shale to active shearing followed by fluid injection. To this end, specimens of Opalinus claystone cored from the Mont Terri underground laboratory in Switzerland were used, which is a good analogue for common caprocks and a target formation for nuclear waste storage (Bossart et al., 2018; Goodman et al., 2017). X‐ray imaging coupled with digital image correlation is used to reveal the temporal and spatial evolution of local fracture aperture changes, in addition to the deformation distributed at locations not reached by the injected fluids.…”

Section: Introductionmentioning

confidence: 99%

Chemo‐Mechanical Coupling in Fractured Shale With Water and Hydrocarbon Flow

Wenning

Madonna

Kurotori

et al. 2021

Geophysical Research Letters

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The transport of chemically reactive fluids through fractured clay‐rich rocks is fundamental to many subsurface engineering technologies. Here, we present results of direct‐shear laboratory experiments with simultaneous imaging by X‐ray Computed Tomography in Opalinus claystone with subsequent fluid injection to unravel the interplay between mechanical fracture deformation, fluid sorption, and flow. Under constant radial stress (σc = 1.5 MPa), the average mechanical aperture trued¯CT increases with shear displacement. Upon brine injection, trued¯CT is reduced by 40% relative to initial conditions (trued¯CT0=140−250 μm) and fluid‐sorption induces a divergent displacement of the two sample halves (Δh = ±50 − 170 μm) quantified by digital image correlation. None of these changes are observed in a control experiment with decane, indicating that creep is subordinate to swelling in sealing the fracture. Swelling‐induced changes in permeability within the fracture are heterogeneous and largely affect the fracture flow field, as computed using numerical simulations.

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“…The Mont Terri Underground Research Laboratory was built for the hydrogeological, geochemical, and geotechnical characterization of the Opalinus Clay formation, which is investigated as a potential host rock for deep geologic nuclear waste disposal in Switzerland. The Opalinus Clay is also quite representative of formations typically considered as caprock in the case of geological carbon dioxide (CO 2 ) storage in deep geological reservoirs (Goodman et al, 2017). The laboratory consists of multiple tunnels and galleries located in the SW-NE trending Mont Terri anticline, which is a flat-ramp-flat structure thrust toward the NW (fault-bend fold) and where the studied fault, although called the "Main Fault" because it is the most deformed zone intersected by the laboratory facilities, is a minor splay (third order structure; Figure 1).…”

Section: Tectonic Setting: Geological Structures Stress Conditions mentioning

confidence: 99%

Complexity of Fault Rupture and Fluid Leakage in Shale: Insights From a Controlled Fault Activation Experiment

Guglielmi

Nussbaum²,

Jeanne

et al. 2020

JGR Solid Earth

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We observed rupture growth caused by controlled fluid injections at 340‐m depth within a fault zone in the low‐permeability Opalinus Clay in the Mont Terri Underground Research Laboratory (Switzerland). The rupture mechanisms were evaluated using measurements of the three‐component borehole wall displacements and fluid pressure in two sections of the fault zone and located horizontally 3 m apart from each other. One section was set across a secondary segment of the fault and used for stepwise fluid injection intended to trigger rupture growth. The other section was set across the principal shear zone of the fault for monitoring. After stepwise pressure increase up to 5.95 MPa at injection, rupture initiated as slip activation, followed by an overall opening of the fault planes connected to the injection. After 19 s of continued injection, displacements arrived at the monitoring point on the principal shear zone. These displacements are about 2.4 times larger than in the secondary fault segment. Overall, the displacements corresponded to a normal fault activation. About 9 s after the displacement front arrived, a strong pressure increase of 4.17 MPa was measured at the monitoring point, indicating a hydraulic connection had formed along the initially very low permeability fault planes between the injection and the monitoring points. Our analyses highlight that the fault activation is consistent with the state of stress but that injection pressure must be close to the normal stress acting on the fault for permeability to be generated and for fluid leakage to occur.

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Large Rock Mass Experimentation @ Mont Terri Underground Research Laboratory – CO2 Containment Assurance Experiments

Cited by 5 publications

References 0 publications

In Situ Direct Displacement Information on Fault Reactivation During Fluid Injection

In Situ Direct Displacement Information on Fault Reactivation During Fluid Injection

Chemo‐Mechanical Coupling in Fractured Shale With Water and Hydrocarbon Flow

Complexity of Fault Rupture and Fluid Leakage in Shale: Insights From a Controlled Fault Activation Experiment

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