67 research outputs found
Lined rock caverns:A hydrogen storage solution
The inherent intermittency of renewable energy sources frequently leads to variable power outputs, challenging the reliability of our power supply. An evolving approach to mitigate these inconsistencies is the conversion of excess energy into hydrogen. Yet, the pursuit of safe and efficient hydrogen storage methods endures. In this perspective paper, we conduct a comprehensive evaluation of the potential of lined rock caverns (LRCs) for hydrogen storage. We provide a detailed exploration of all system components and their associated challenges. While LRCs have demonstrated effectiveness in storing various materials, their suitability for hydrogen storage remains a largely uncharted territory. Drawing from empirical data and practical applications, we delineate the unique challenges entailed in employing LRCs for hydrogen storage. Additionally, we identify promising avenues for advancement and underscore crucial research directions to unlock the full potential of LRCs in hydrogen storage applications. The foundational infrastructure and associated risks of large-scale hydrogen storage within LRCs necessitate thorough examination. This work not only highlights challenges but also prospects, with the aim of accelerating the realization of this innovative storage technology on a practical, field-scale level.</p
Injection of CO2-saturated brine in geological reservoir: a way to enhanced storage safety
Injection of free-phase supercritical CO2 into deep geological reservoirs is associated with risk of considerable return flows towards the land surface due to the buoyancy of CO2, which is lighter than the resident brine in the reservoir. Such upward movements can be avoided if CO2 is injected in the dissolved phase (CO2aq). In this work, injection of CO2-saturated brine in a subsurface carbonate reservoir was modelled. Physical and geochemical interactions of injected low-pH CO2-saturated brine with the carbonate minerals (calcite, dolomite and siderite) were investigated in the reactive transport modelling. CO2-saturated brine, being low in pH, showed high reactivity with the reservoir minerals, resulting in a significant mineral dissolution and CO2 conversion in reactions. Over the injection period of 10 yr, up to 16% of the injected CO2 was found consumed in geochemical reactions. Sorption included in the transport analysis resulted in additional quantities of CO2 mass stored. However, for the considered carbonate minerals, the consumption of injected CO2aq was found mainly in the form of ionic trapping.Peer ReviewedPostprint (author's final draft
Artificial Neural Network-Based Caprock Structural Reliability Analysis for CO2 Injection SiteâAn Example from Northern North Sea
publishedVersio
Insights into past tectonism from authigenic quartz
Authigenic quartz grains carry information that is diagnostic for the thermal history and thereby the burial depth and uplift of sediments. Recycled quartz grains with embayed or rounded authigenic remnants have been observed globally, but the value of these grains in unravelling past tectonism is presently underexplored. In this study, we launch a new method to demonstrate that cathodoluminescence (CL) in combination with fluid inclusion data and textural characteristics of authigenic quartz can provide important information about past tectonic activity. Vital in the method is the realisation that recycled quartz grains can be distinguished from other quartz grains by their geochemical CL fingerprint, allowing tracking of uplifted source terrains in a direction towards higher fractions of the recycled grains. Furthermore, regional mapping can reveal both intra-basinal recycling as well as recycled grains transported into the basin from external sources. The new proposed method is simple and does not require more than a standard Scanning Electron Microscope equipped with a CL detector, available at many geoscientific institutions worldwide. This innovative approach applies to a wide section of geoscientific disciplines, and complement and supplement other conventional methods used for unravelling past tectonism.publishedVersio
Injection of CO2-saturated brine in geological reservoir: a way to enhanced storage safety
Injection of free-phase supercritical CO2 into deep geological reservoirs is associated with risk of considerable return flows towards the land surface due to the buoyancy of CO2, which is lighter than the resident brine in the reservoir. Such upward movements can be avoided if CO2 is injected in the dissolved phase (CO2aq). In this work, injection of CO2-saturated brine in a subsurface carbonate reservoir was modelled. Physical and geochemical interactions of injected low-pH CO2-saturated brine with the carbonate minerals (calcite, dolomite and siderite) were investigated in the reactive transport modelling. CO2-saturated brine, being low in pH, showed high reactivity with the reservoir minerals, resulting in a significant mineral dissolution and CO2 conversion in reactions. Over the injection period of 10 yr, up to 16% of the injected CO2 was found consumed in geochemical reactions. Sorption included in the transport analysis resulted in additional quantities of CO2 mass stored. However, for the considered carbonate minerals, the consumption of injected CO2aq was found mainly in the form of ionic trapping
Assessing salt precipitation and weak acid interaction in subsurface CO2 injection: Potential 50% strength decline in near-wellbore reservoir sandstones
Predictive modeling of CO2 storage sites requires a detailed understanding of
physico-chemical processes and potential challenges for scale-up. Dramatic
injectivity decline may occur due to salt precipitation pore clogging in
high-salinity reservoirs, even over a short time frame. This study aims to
elucidate the adverse impact of CO2-induced salt crystallization in porous
media on the geomechanical properties of near-wellbore reservoir sandstones. As
the impact of salt precipitation cannot be isolated from the precursor effects
of interaction with CO2 and carbonic acid, we initiated our study by a
comprehensive review of CO2 chemo-mechanical interactions with sandstones. We
conducted laboratory geochemical CO2-brine-rock interactions at elevated
pressures and temperatures on two sets of porous sandstone with contrasting
petrophysical qualities. Two paths were followed: treatment with (a)
CO2-acidified brine at 10 MPa fluid pressure and 60C for 7 days, and a second
subset continuation with (b) supercritical injection until complete dry-out and
salt precipitation. Afterward, the core samples were tested in a triaxial
apparatus at varying stresses and temperatures. The elastic moduli of intact,
CO2-reacted, and salt-damaged sandstones were juxtaposed to elucidate the
extent of crystallization damages. The salt-affected specimens showed a maximum
of 50 percent reduction in Young's and shear moduli and twice an increase in
Poisson's ratio compared to intact condition. The deterioration was notably
higher for the tighter rocks with higher initial stiffness
Constraints on natural global atmospheric CO2 fluxes from 1860 to 2010 using a simplified explicit forward model
Land-use changes until the beginning of the 20th century made the terrestrial biosphere a net source of atmospheric carbon. Later, burning of fossil fuel surpassed land use changes as the major anthropogenic source of carbon. The terrestrial biosphere is at present suggested to be a carbon sink, but the distribution of excess anthropogenic carbon to the ocean and biosphere sinks is highly uncertain. Our modeling suggest that land-use changes can be tracked quite well by the carbon isotopes until mid-20th century, whereas burning of fossil fuel dominates the present-day observed changes in the isotope signature. The modeling indicates that the global carbon isotope fractionation has not changed significantly during the last 150 years. Furthermore, increased uptake of carbon by the ocean and increasing temperatures does not yet appear to have resulted in increasing the global gross ocean-to-atmosphere carbon fluxes. This may however change in the future when the excess carbon will emerge in the ocean upwelling zones, possibly reducing the net-uptake of carbon compared to the present-day ocean
Interactions between CO2, saline water and minerals during geological storage of CO2
This doctoral thesis is based on the following papers: Paper A: Hellevang, H., Aagaard, P., Oelkers, E.H., and Kvamme, B., 2005. Can dawsonite permanently trap CO2? Environmental Science and Technology, 39, 8281-8287. Paper B: Hellevang, H., Kvamme, B., and Aagaard, P., 2004. Long term interactions between minerals and reactive fluids - Stability of dawsonite. In Proceedings of the Third Annual Conference on Carbon Capture and Sequestration DOE/NETL, Alexandria, VA, May 3-6, 1-7 Paper C: Hellevang, H., and Kvamme, B. CO2-water-rock interactions - ACCRETE simulations of geological storage of CO2. Submitted to Applied Geochemistry. Paper D: Hellevang, H., Kumar, S., Fladmark, G., and Kvamme, B. CO2 storage in the Utsira Formation â ATHENA 3D reactive transport simulations. Submitted to Basin Research. Paper E: Hellevang, H., and Kvamme, B. 2006. ACCRETE â Geochemistry solver for CO2-water-rock interactions. Paper submitted to GHGT8, Trondheim, June 19-22, 2006. Paper F: Khattri, S.K., Hellevang, H., Fladmark, G.E., and Kvamme, B. 2006. Deposition of Green House Gases by Compositional Simulator: Long Term Reactive Transport of CO2 in the Sand of Utsira. Submitted to Transport in Porous Media
FluidâRock Interactions in ClayâRich Seals: Impact on Transport and Mechanical Properties
Fluidârock interaction in lowâpermeable clayârich seal units is an important topic for the evaluation of the longâterm seal integrity during geological storage of CO2. In lowâpermeable sealing units, the diffusion of CO2 into the matrix is a slow process, and studies of CO2âinitiated fluidârock interaction in seals are challenging. In this paper, we present an overview of CO2 transport mechanism and fluidârock interaction processes that might alter mechanical and transport properties of seals. The review includes theoretical considerations and simulations, experimentally demonstrated processes, and field examples of flow and fluidârock interaction in intact clayârich seals as well as for fractures. For clayârich seals dominated by minerals like quartz, illite, and smectite, the reactivity due to drop in pH is found to be low, and most reaction observed is found to involve calcite. Only minor porosity changes are observed, and implications for flow and CO2 transport are uncertain due to limited data available. Swelling and shrinking property of smectites due to CO2 sorption and CO2 alterations within fractures in clayârich seal is hardly addressed in the literature.FluidâRock Interactions in ClayâRich Seals: Impact on Transport and Mechanical PropertiesacceptedVersio
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