Geotechnical investigations of cap rocks above CO2 -resevoirs

Mutschler, Thomas; Triantafyllidis, Theodoros; Balthasar, K.

doi:10.1016/j.egypro.2009.02.126

Cited by 5 publications

(6 citation statements)

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“…The presence of faults and fractures in seals, even if they cause only a minor enhancement of seal permeability prior to CO 2 injection, implies that models that describe the seals as homogeneous may underestimate the sensitivity of k v and P c,b to geochemical and geomechanical alteration. ,,,,,,− Three lines of evidence indicate that clays and clay minerals play an important role in this sensitivity. First, conventional hydrocarbon exploration studies have found that, despite the structural and petrophysical complexity of faults, ,,, the barrier properties of faults are primarily determined by the clay content of the fault-filling material as quantified by proxies such as the shale gouge ratio (SGR). ,− With increasing clay content or SGR, fault permeability decreases from ∼10 –15 to 10 –19 m 2 and P c,b increases from ∼0.1 to 10 MPa. , Second, the fault friction coefficient μ s of the Mohr–Coulomb failure model, an important parameter in the brittle failure of rocks and the mechanics of slip along faults and fractures, ,,,− depends strongly on clay content: μ s values range from 0.6 to 0.85 for most rocks, ,, but clay-rich rocks can have μ s values as low as 0.2. ,,,,− Clay-rich rocks also tend to deform in a more ductile, self-sealing manner than other rocks, a desirable seal property. ,,,, Finally, the stress-porosity-permeability relations of porous media (or stress-aperture-permeability, in the case of unfilled fractures), of key importance in predicting the permeability of preferential flow paths in seals, ,,, are highly sensitive to clay content. ,, For example, the permeability k of sedimentary rocks is routinely modeled as having a power-law dependence on porosity ϕ, where n ∼ 3 in homogeneous, nonclayey media and larger n values are associated with emergent phenomena such as wormhole-like or bedding-oriented dissolution paterns ,<...…”

Section: Key Parameters In Co2 Trapping Predictionsmentioning

confidence: 99%

The Nanoscale Basis of CO₂ Trapping for Geologic Storage

Bourg

Beckingham

DePaolo

2015

Environ. Sci. Technol.

123

110

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Carbon capture and storage (CCS) is likely to be a critical technology to achieve large reductions in global carbon emissions over the next century. Research on the subsurface storage of CO2 is aimed at reducing uncertainties in the efficacy of CO2 storage in sedimentary rock formations. Three key parameters that have a nanoscale basis and that contribute uncertainty to predictions of CO2 trapping are the vertical permeability kv of seals, the residual CO2 saturation Sg,r in reservoir rocks, and the reactive surface area ar of silicate minerals. This review summarizes recent progress and identifies outstanding research needs in these areas. Available data suggest that the permeability of shale and mudstone seals is heavily dependent on clay fraction and can be extremely low even in the presence of fractures. Investigations of residual CO2 trapping indicate that CO2-induced alteration in the wettability of mineral surfaces may significantly influence Sg,r. Ultimately, the rate and extent of CO2 conversion to mineral phases are uncertain due to a poor understanding of the kinetics of slow reactions between minerals and fluids. Rapidly improving characterization techniques using X-rays and neutrons, and computing capability for simulating chemical interactions, provide promise for important advances.

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Section: Key Parameters In Co2 Trapping Predictionsmentioning

confidence: 99%

The Nanoscale Basis of CO₂ Trapping for Geologic Storage

Bourg

Beckingham

DePaolo

2015

Environ. Sci. Technol.

123

110

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“…Experiments on well-rock samples show an elasto-plastic behaviour of the rock and a self sealing behaviour of faults. Geomechanical models based on the observed rock properties indicate that no fault reactivation should occur if a smooth pressure increase is applied (Mutschler et al, 2009, Rübel et al, 2008.…”

Section: Site Preparation and Injection Facilitymentioning

confidence: 99%

CO2SINK—From site characterisation and risk assessment to monitoring and verification: One year of operational experience with the field laboratory for CO2 storage at Ketzin, Germany

Würdemann

Möller

Kühn

et al. 2010

International Journal of Greenhouse Gas Control

150

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The CO 2 SINK pilot project at Ketzin is aimed at a better understanding of geological CO 2 storage operation in a saline aquifer. The reservoir consists of fluvial deposits with average permeability ranging between 50 and 100 mDarcy. The main focus of CO 2 SINK is developing and testing of monitoring and verification technologies. All wells, one for injection and two for observation, are equipped with smart casings (sensors behind casing, facing the rocks) containing a Distributed Temperature Sensing (DTS) and electrodes for Electrical Resistivity Tomography (ERT). The in-hole Gas Membrane Sensors (GMS) observed the arrival of tracers and CO 2 with high temporal resolution. Geophysical monitoring includes Moving Source Profiling (MSP), Vertical Seismic Profiling (VSP), crosshole, star and 4-D seismic experiments. Numerical models are benchmarked via the monitoring results indicating a sufficient match between observation and prediction, at least for the arrival of CO 2 at the first observation well. Downhole samples of brine showed changes in the fluid composition and biocenosis. First monitoring results indicate anisotropic flow of CO 2 coinciding with the -on-time‖ arrival of CO 2 at observation well one (Ktzi 200) and the later arrival at observation well two (Ktzi 202). A risk assessment was performed prior to the start of injection. After one year of operations about 18,000 t of CO 2 were injected safely.

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“…Similarly, cohesion values were estimated using a proprietary correlation with sonic log data. Mutschler et al (2009) performed triaxial loading on claystone samples recovered from the injection well at the Ketzin pilot test. They focussed primarily on the impact of sample scale on viscosity index, which was found to be negligible at the sizes tested and also observed the transition from brittle to ductile deformation at higher effective pressures.…”

Section: Characterisation Of Rocks At Depleted Sitesmentioning

confidence: 99%

Caprock integrity and public perception studies of carbon storage in depleted hydrocarbon reservoirs

Paluszny

Graham

Daniels

et al. 2020

International Journal of Greenhouse Gas Control

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Capture and subsurface storage of CO 2 is widely viewed as being a necessary component of any strategy to minimise and control the continued increase in average global temperatures. Existing oil and gas reservoirs can be re-used for carbon storage, providing a substantial fraction of the vast amounts of subsurface storage space that will be required for the implementation of carbon storage at an industrial scale. Carbon capture and storage (CCS) in depleted reservoirs aims to ensure subsurface containment, both to satisfy safety considerations, and to provide confidence that the containment will continue over the necessary timescales. Other technical issues that need to be addressed include the risk of unintended subsurface events, such as induced seismicity. Minimisation of these risks is key to building confidence in CCS technology, both in relation to financing/liability, and the development and maintenance of public acceptance. These factors may be of particular importance with regard to CCS projects involving depleted hydrocarbon reservoirs, where the mechanical effects of production activities must also be considered. Given the importance of caprock behaviour in this context, several previously published geomechanical caprock studies of depleted hydrocarbon reservoirs are identified and reviewed, comprising experimental and numerical studies of fourteen CCS pilot sites in depleted hydrocarbon reservoirs, in seven countries (

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Geotechnical investigations of cap rocks above CO2 -resevoirs

Cited by 5 publications

References 0 publications

The Nanoscale Basis of CO₂ Trapping for Geologic Storage

The Nanoscale Basis of CO₂ Trapping for Geologic Storage

CO2SINK—From site characterisation and risk assessment to monitoring and verification: One year of operational experience with the field laboratory for CO2 storage at Ketzin, Germany

Caprock integrity and public perception studies of carbon storage in depleted hydrocarbon reservoirs

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Geotechnical investigations of cap rocks above CO2 -resevoirs

Cited by 5 publications

References 0 publications

The Nanoscale Basis of CO2 Trapping for Geologic Storage

The Nanoscale Basis of CO2 Trapping for Geologic Storage

CO2SINK—From site characterisation and risk assessment to monitoring and verification: One year of operational experience with the field laboratory for CO2 storage at Ketzin, Germany

Caprock integrity and public perception studies of carbon storage in depleted hydrocarbon reservoirs

Contact Info

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The Nanoscale Basis of CO₂ Trapping for Geologic Storage

The Nanoscale Basis of CO₂ Trapping for Geologic Storage