After decades of research on carbon capture and geologic sequestration (CCS), the world needs to finally move from pilot and demonstration experiments to industrial-scale implementation. CCS at scale will involve unprecedented fluid injection volumes that can result in large-scale pressure increases in the subsurface and may cause unwanted geomechanical effects, such as generating seismic...
The potential of CO2 underground storage relies on the sealing efficiency of the overlaying caprock that acts as a geological barrier. Shales are extensively studied as potential caprock formations thanks to their favourable hydro-mechanical properties and their sealing capacity: low permeability, high sorption capacity, high swelling ability and high capillary entry pressure. The sealing...
Compositional flow is an important feature of numerical models in the context of gas storage in the subsurface. In practice, not only maximum inflow and outflow rates, development of reservoir pressure and gas plume shape in time are important, but because the gas is to be extracted and, e.g., combusted in a turbine, its molecular composition is of great interest. In addition, dissolution of...
In the CO2 sequestration process, the solubility-trapping mechanism is one of the key mechanisms, which contributes to the safe eradication of injected supercritical CO2 (ScCO2). When ScCO2 is injected into the reservoir domain, it will start migrating upwards due to its low density as compared to reservoir water. During this migration, some amount of CO2 will be dissolved into the reservoir...
Pilot projects to sequester CO$_2$ in geologic formations as part of Carbon Capture and Sequestration (CCS) efforts to mitigate anthropogenic climate change have obtained evidence of the mineralization of injected CO$_2$. Basalt aquifers like in CarbFix and the Wallula Basalt Pilot Project contain minerals like olivine which can liberate ions to mineralize and deposit the carbonates as they...
Due to the high storage capacity and the long-term sequestration safety, geological CO2 mineralization in mafic and ultramafic reservoir has been widely researching via laboratory and field studies. Previous researches mainly focus on the dynamics of CO2-water-rock interactions in well-mixed constant pressure system, few studies have been carried out with pressure decay while CO2...
Geologic CO2 sequestration into deep saline aquifers is one strategy to reduce global atmospheric CO2 levels. Injectivity plays a key role in determining the storage capacity of aquifers. During CO2 injection into an aquifer, acid dissolution of carbonates arises due to CO2-acidification of formation water, enhancing permeability and connectivity. While salt precipitation within the...
Injection-induced seismicity has arisen as a central concern in the development of subsurface energy technologies such as enhanced geothermal energy, unconventional hydrocarbon production, wastewater injection, geologic carbon sequestration, or underground gas storage. The effect of the hydraulic properties of faults on the rupture of injection-induced earthquakes is still poorly understood....
With an ever-increasing global warming scenario, geological sequestration stands as an effective mean to trap gases such as carbon dioxide (CO$_2$) towards long-term storage. The subsurface trapping mechanisms occurring upon injection of supercritical carbon dioxide (sCO$_2$) are structural, residual, solubility, and mineral trapping [1-3]. Among them, success of solubility trapping dictates...
CO2 injection in deep saline aquifer formations is a promising scheme to reduce the emissions of CO2 into the atmosphere. The migration of injected CO2 can be characterized as multiphase flow in porous media where CO2 displaces brine in porous reservoir rocks. The migration observed with 4D seismic data often suggests that the shape of a CO2 plume is strongly affected by thin shale layers...
Geologic sequestration in sedimentary formations has been identified as a potential technology to prevent climate-change inducing carbon dioxide (CO$_2$) from being emitted to the atmosphere. In order to achieve safe and effective storage underground, accurate understanding and predictions of CO$_2$ behavior in subsurface rock formations is required; including quantifying how much CO$_2$ is...
Geologic carbon sequestration can play an important role in reducing the amount of greenhouse gasses emitted to the atmosphere. To ensure the long-term security of the injected CO2, a good understanding of the fate of the plume is needed. Small scale (mm-m scale) rock structure heterogeneities impact the local capillary forces and, therefore, a capillary potential at the scale of the...
With global warming and increasing carbon dioxide concentrations in the atmosphere being probably one of the main scientific challenges of the XXIst century, the need to develop and implement Carbon Capture and Storage (CCS) technologies is more and more pressing. One possible solution which has been recently gaining momentum, is the storage of CO2 as solid carbonates, which offers a much...
CO2 injection into deep saline aquifers has shown to be a feasible option in many locations in the world, as for their large storage capacity under safe operational conditions. Previous studies have revealed that CO2 can be trapped in the subsurface by several mechanisms, including hydrodynamical, residual, dissolution, and mineral trapping. Despite the major advances in studying these...
Supply of green energy to society can successfully happen if large-scale storage technologies are developed. Underground hydrogen storage (UHS) in initially brine-saturated deep porous rocks is a promising option, due to hydrogen's high specific energy capacity and the high volumetric capacity of aquifers.
Appropriate selection of a feasible and safe storage site vitally depends on...
An efficient energy-management strategy is critical for the fast transition of the global energy sector towards operation with 100% renewable or low-carbon energy, of which energy-storage is a key part. Among energy storage technologies, the geological storage of hydrogen, utilising excess or curtailed renewable energy and electrolysis has emerged as a Terawatt-scale, clean and sustainable...
The dissolution of carbon-dioxide (CO$_2$) in deep saline aquifers is an important trapping mechanism in carbon storage. This process is triggered by unstable high-density CO$_2$ front, which later promotes density-driven mixing, hydrodynamic dispersion of CO$_2$ and favors the long-term sequestration. In many former studies, the effects of hydrodynamic dispersion and multispecies geochemical...
Deep saline aquifers are appropriate for the long-term storage of captured CO2[1]. Low pH environments of deep aquifers due to CO2 injection and dissolution would trigger rock dissolution while the extent of rock dissolution depends on the brine chemistry[2]. Carbonates are the main mineral forming the matrix of carbonate rocks[3]. Moreover, carbonate minerals show higher kinetic reactivity in...
Methane often generates in fine-grained marine muds by the biodegradation of organic matter but accumulates in neighboring coarse sand layers in the form of hydrates. This phenomenon is attributed to the higher capillary pressure in mud layers than in sand layers, which makes hydrate accumulation in sand layers more thermodynamically favorable. However, rarely explored is its kinetics, i.e.,...
We consider fracture propagation driven by cooling that is mainly caused by convection cells inside vertical fractures. The process, known as convective downward migration, has been proposed as a mechanism for transport of heat in the deep roots of volcanic geothermal systems. It is also predicted to have an important role in the source mechanism of hydrothermal activity in a more general...
Carbon capture and storage (CCS) is recognized as one of the most effective technologies for reducing CO2 emissions in the short to medium term. This three-phase process that includes: (i) capture of CO2, (ii) transportation, and (iii) underground injection of CO2 into the geological formations for storage, has highlighted that subsurface energy technologies will play a central role in the...
