Anja Sundal

• Bredal, Marie Bergvik; Rouyet, Line; Wendt, Lotte; Hindberg, Heidi; Stødle, Daniel & Lauknes, Tom Rune [Vis alle 14 forfattere av denne artikkelen] (2026). Brief communication: InSAR Svalbard Ground Motion Service – observing surface displacements in the High Arctic. Earth Observation (EO). 1(1), s. 121–128. doi: 10.5194/eo-1-121-2026. Fulltekst i vitenarkiv Vis sammendrag

  The InSAR Svalbard Ground Motion Service (GMS) provides open-access surface displacement maps and time series in the Svalbard archipelago, derived from Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR). The service provides seasonal products capturing short-term 2016–2024 displacements and interannual products documenting long-term 2018–2024 velocity trends. InSAR Svalbard covers five areas on Spitsbergen Island (Longyearbyen, Ny-Ålesund, Svea, Hornsund and Kapp Linné). The service consists in a web-based visualisation tool at https://svalbard.insar.no/ (release date: 2 February 2026, last access: 22 September 2026). The products are also distributed at https://doi.org/10.5281/zenodo.18442696 (Bredal et al., 2026a). InSAR Svalbard establishes a foundation for geohazard assessment in Arctic regions and interdisciplinary research on permafrost dynamics, ground stability, and environmental changes.

• Meneguolo, Renata; Sundal, Anja; Martinius, Allard W.; Veselovsky, Zbynek; Cullum, Alex & Milovanova, Elvira (2022). Impact of the lower Jurassic Dunlin Group depositional elements on the Aurora CO<inf>2</inf> storage site, EL001, northern North Sea, Norway. International Journal of Greenhouse Gas Control. ISSN 1750-5836. 119. doi: 10.1016/j.ijggc.2022.103723. Fulltekst i vitenarkiv
• Holden, Nora; Osmond, Johnathon L.; Mulrooney, Mark Joseph; Braathen, Alvar; Skurtveit, Elin & Sundal, Anja (2022). Structural characterization and across-fault seal assessment of the Aurora CO<inf>2</inf> storage site, northern North Sea. Petroleum Geoscience. ISSN 1354-0793. 28(4). doi: 10.1144/petgeo2022-036. Fulltekst i vitenarkiv Vis sammendrag

  Faults play an essential role at many potential CO2 storage sites because they can act as conduits or barriers to fluid flow. To contribute to the evaluation of the Aurora storage site in the northern North Sea, we perform a structural characterization and assessment of across-fault seals that displace the Lower Jurassic storage complex. We find that first-order faults are predominately north–south striking and west dipping, with throws greater than the thickness of the primary seal (>85 m). In contrast, second-order faults have lower throws (15–50 m), and variable strike and dip directions. Due to the dip of the storage complex, injected CO2 is likely to migrate northwards before encountering the first-order Svartalv Fault Zone on its footwall side, which juxtaposes the storage units against younger sand-rich units. However, shale gouge ratio values exceed 0.30 at the depth of the storage complex, suggesting that a fault membrane seal may be present. Furthermore, second-order NE-dipping faults create juxtaposition seals and, in places, small-scale structural traps (24–48 m) along the Svartalv Fault Zone. Overall, we suggest that faults within the Aurora storage site could provide barriers to plume migration, allowing more CO2 to become trapped and thereby increasing the storage capacity.

• Weber, Ulrich Wolfgang; Kampman, Niko & Sundal, Anja (2021). On the Distinctiveness of Noble Gases in Injected Co2 from Background Fluids. I Røkke, Nils Anders & Knuutila, Hanna K (Red.), TCCS–11. CO2 Capture, Transport and Storage. Trondheim 22nd–23rd June 2021. Short Papers from the 11th International Trondheim CCS Conference. SINTEF akademisk forlag. ISSN 9788253617145. s. 182–187. Fulltekst i vitenarkiv Vis sammendrag

  A comprehensive monitoring program for CO2 storage sites is an integral part of designing CCS projects. Once a CO2 anomaly is observed or suspected, the source of the CO2 may be identified through evaluation of geochemical tracers. Noble gases are one of those geochemical tracers that display unique signatures for the environmental reservoirs involved in the storage site system. The background fluids at storage prospect, such as formation water, hydrocarbons or shallow gases need to be characterized prior to injection. Typical noble gas signatures are of atmospheric, crustal/radiogenic or mantle character. Captured CO2 can contain a large range of noble gas concentrations and ratios with typically significantly lower concentrations than the other background fluids. Here, we collect the noble gas analysis of various environmental fluids in the storage site system relevant to the North Sea, such as hydrocarbons and shallow gases, to narrow down possible observable signatures. If samples are not available realistic values can be inferred from analogue sites/studies. Further, we show that after injection, phase partitioning, hence equilibration, of the injected CO2 with formation water leads to adaption of a radiogenic signature from the formation water. Therefore, the initially low concentrations of the CO2, and their associated elemental and isotopic ratios, are only preserved when remaining almost pure. These signatures can be applied to mixing calculations with the background fluids to rule out if injected CO2 is contributing to an anomaly. Meanwhile, noble gases are one of the environmental tracers that could be cost-effective since they are naturally inherent in the CO2 and the storage reservoir fluids, we also model the addition of artificial noble gas tracers to increase the detectability, i.e. ability to recognize lower contributions of injected CO2 in a background reservoir fluid. These calculations can be fed into cost calculations to estimate the economic impact of such an additional monitoring measure.

• Skurtveit, E.; Torabi, Anita; Sundal, Anja & Braathen, A. (2021). The role of mechanical stratigraphy on CO<inf>2</inf> migration along faults – examples from Entrada Sandstone, Humbug Flats, Utah, USA. International Journal of Greenhouse Gas Control. ISSN 1750-5836. 109. doi: 10.1016/j.ijggc.2021.103376. Fulltekst i vitenarkiv Vis sammendrag

  Bleaching patterns along a faulted succession provides new insight into fluid migration pathways controlled by the fault zone and mechanical stratigraphy. In order to investigate this effect, we logged stratigraphic layers in Humbug Flats, Utah, USA both in host rocks and faulted rocks, where a 40 m offset normal fault cuts through the Entrada Sandstone. We measured petrophysical and mechanical properties using TinyPerm II, Schmidt Hammer and laboratory core testing for selected layers. Bleaching has been identified as a proxy for fluid migration parallel to bedding, which fades out with distance from faults. A new observation is that fracturing of bed interfaces contributes to horizontal flow out from the fault zone. Longer-distance comprehensive bleaching dominates the most permeable beds (units), hosting porosity-controlled deformation band associated to fault zones. Fractures prevail in low permeability and stiffer units, where isolated fracture parallel bleaching haloes are observed within fault damage and process zones. Strong correlation is observed between permeability/porosity and stiffness/strength properties for the tested samples of different layers along the stratigraphic logs. For the studied fault, fractures provide important conduits for vertical flow across low permeability and stiff layers, whereas the more porous layers provide bedding-parallel flow paths out of the fault zone.

• Andersen, Odd & Sundal, Anja (2021). Estimating Caprock Impact on CO2 Migration in the Gassum Formation Using 2D Seismic Line Data. Transport in Porous Media. ISSN 0169-3913. 138, s. 459–487. doi: 10.1007/s11242-021-01622-1. Fulltekst i vitenarkiv Vis sammendrag

  Realizable CO2 storage potential for saline formations without closed lateral boundaries depends on the combined effects of physical and chemical trapping mechanisms to prevent long-term migration out of the defined storage area. One such mechanism is the topography of the caprock surface, which may retain CO2 in structural pockets along the migration path. Past theoretical and modeling studies suggest that even traps too small to be accurately described by seismic data may play a significant role. In this study, we use real but scarce seismic data from the Gassum Formation of the Norwegian Continental shelf to estimate the impact of topographical features of the top seal in limiting CO2 migration. We seek to estimate the amount of macro- and sub-scale trapping potential of the formation based on a few dozen interpreted 2D seismic lines and identified faults. We generate multiple high-resolution realizations of the top surface, constructed to be faithful to both large-scale topography and small-scale statistical properties. The structural trapping and plume retardation potential of these top surfaces is subsequently estimated using spill-point (static) analysis and dynamical flow simulation. By applying these techniques on a large ensemble of top surface realizations generated using a combination of stochastic realizations and systematic variation of key model parameters, we explore the range of possible impacts on plume advancement, physical trapping and migration direction. The stochastic analysis of trapping capacity and retardation efficiency in statistically generated, sub-seismic resolution features may also be applied for surfaces generated from 3D data.

• Weber, Ulrich Wolfgang; Kipfer, Rolf; Horstmann, Edith; Ringrose, Philip; Kampman, Niko & Tomonaga, Yama [Vis alle 8 forfattere av denne artikkelen] (2021). Noble gas tracers in gas streams at Norwegian CO2 capture plants. International Journal of Greenhouse Gas Control. ISSN 1750-5836. 106. doi: 10.1016/j.ijggc.2020.103238. Fulltekst i vitenarkiv Vis sammendrag

  Carbon capture and storage (CCS) may play a significant role in reducing greenhouse gas emissions. Noble gases are potential tracers to monitor subsurface CO2 storage sites and verify their containment. Naturally occurring noble gases have been used successfully to refute alleged CO2 leakage in the past. We present results from several sampling campaigns at two Norwegian CO2 capture facilities, the demonstration plant Technology Centre Mongstad (TCM) and the natural gas processing plant with CO2 capture and storage on Melkøya. The gas streams in the capture plants were monitored with a combination of on-site mass spectrometry and subsequently analysed discrete samples. This allows us to define the factors controlling noble gas concentrations in captured CO2, to monitor temporal variation of noble gas concentrations and finally evaluate the potential to use noble gases as inherent environmental tracers for labelling CO2 in storage reservoirs. At both sites, CO2 is captured using amine gas treatment. Noble gas concentrations in the gas streams were observed to decrease by several orders of magnitude during the processing. Isotopic ratios are air-like for CO2 captured after natural gas combustion at TCM and natural gas-like for CO2 captured from natural gas processing on Melkøya. Further, we detected a solubility trend caused by the amine solvent at TCM with higher solubility for heavier noble gases. We find that the relative concentrations of noble gases in the captured CO2 are defined by the gas from which the CO2 is captured and the design of the amine gas treatment process. Both factors were observed to cause temporal variation in the captured CO2. Using mixing and noble gas partitioning calculations we show that the significant depletion in noble gas concentrations, together with degassing of noble gas enriched formation water, means that the injected CO2 will inherit the noble gas signature of the storage formation, even following the injection of significant CO2 volumes. Any CO2 leaked from the storage formation is thus likely to have a crustal noble gas signature, characteristic of the storage site, which can be targeted for monitoring.

• Weber, Ulrich Wolfgang; Kampman, Niko & Sundal, Anja (2021). Techno-Economic Aspects of Noble Gases as Monitoring Tracers. Energies. 14(12). doi: 10.3390/en14123433. Fulltekst i vitenarkiv Vis sammendrag

  A comprehensive monitoring program is an integral part of the safe operation of geological CO2 storage projects. Noble gases can be used as geochemical tracers to detect a CO2 anomaly and identify its origin, since they display unique signatures in the injected CO2 and naturally occurring geological fluids and gases of the storage site complex. In this study, we assess and demonstrate the suitability of noble gases in source identification of CO2 anomalies even when natural variability and analytical uncertainties are considered. Explicitly, injected CO2 becomes distinguishable from shallow fluids (e.g., subsea gas seeps) due to its inheritance of the radiogenic signature (e.g., high He) of deep crustal fluids by equilibration with the formation water. This equilibration also results in the CO2 inheriting a distinct Xe concentration and Xe/noble gas elemental ratios, which enable the CO2 to be differentiated from deep crustal hydrocarbon gases that may be in the vicinity of a storage reservoir. However, the derivation has uncertainties that may make the latter distinction less reliable. These uncertainties would be best and most economically addressed by coinjection of Xe with a distinct isotope ratio into the CO2 stream. However, such a tracer addition would add significant cost to monitoring programs of currently operating storage projects by up to 70% (i.e., from 1 $US/t to 1.7 $US/t).

• Masoudi, Mohammad; Sundal, Anja & Hellevang, Helge (2021). Estimation of Mutual Solubility of CO2-H2O in Saline Aquifer Systems Using ePC-SAFT Equation of State. I Røkke, Nils Anders & Knuutila, Hanna K (Red.), TCCS–11. CO2 Capture, Transport and Storage. Trondheim 22nd–23rd June 2021. Short Papers from the 11th International Trondheim CCS Conference. SINTEF akademisk forlag. ISSN 9788253617145. Fulltekst i vitenarkiv Vis sammendrag

  A primary assessment of mutual solubility of CO2 and water for estimated max and min temperatures and pressures of the prospective reservoir formations of Aurora; Cook (at >2650 m depth) and Johansen (at >2700 m depth) have been done using ePC-SAFT equation of estate. Mole fraction of CO2 in H2O ranges from 0.025 to 0.027, and H2O in CO2 form 0.016 to 0.023 over pressure-temperature ranges of 265 – 283 bar and 95 – 110 °C. The potential for drying out effects (H2O to CO2) is significant, and there would be risk of salt precipitation in the near well area.

• Braathen, Alvar; Petrie, Elisabeth; Nystuen, Tonje; Sundal, Anja; Skurtveit, Elin & Zuchuat, Valentin [Vis alle 8 forfattere av denne artikkelen] (2020). Interaction of deformation bands and fractures during progressive strain in monocline - San Rafael Swell, Central Utah, USA. Journal of Structural Geology. ISSN 0191-8141. 141. doi: 10.1016/j.jsg.2020.104219. Fulltekst i vitenarkiv Vis sammendrag

  Folds in porous sandstone in cases allow identification of progressive deformation in an evolving strain field. In the Navajo Sandstone of the km-scale Laramide-style monocline of the San Rafael Swell (Utah, USA), four populations of small-scale structures record different kinematics and deformation mechanisms, depending on orientation to bedding within the first-order fold. Small-scale structures span from cataclastic (shear-) compaction and shear-isochoric deformation bands to dominant disaggregation (shear-) dilation bands. Extension and shear fractures record transformations from band to fracture formation, adding to the structural diversity. Early structures record semi-penetrative shear deformation guided by bedding and lamination in eolian deposits, consistent with layer-parallel shortening. Subsequent deformation is localized and at a higher angle relative to bedding, recording forward-directed and subsequently backward-directed shear structures within the east-verging monocline. Final deformation is highly localized and appears as a conjugate set of sub-vertical shear zones with shortening-extension axes oblique to the monocline. For the given conditions in a progressive shear system in highly porous sandstones, interactions of deformation bands and fractures suggest a revival of deformation bands by mutual shear band-fracture systems as developing band swarms rotate into an extensional strain sector during folding. In cases of deformation by shear-dilation strain, deformation bands may evolve directly into fractures, as grain contacts are lost.

• Braathen, Alvar; Petrie, Elizabeth; Nystuen, Tonje; Sundal, Anja; Midtkandal, Ivar & Skurtveit, Elin [Vis alle 7 forfattere av denne artikkelen] (2020). Interaction of deformation bands and fractures during progressive strain in monocline - San Rafael Swell, Central Utah, USA. Journal of Structural Geology. ISSN 0191-8141. Fulltekst i vitenarkiv
• Parvin, Saeed; Masoudi, Mohammad; Sundal, Anja & Miri, Rohaldin (2020). Continuum scale modelling of salt precipitation in the context of CO2 storage in saline aquifers with MRST compositional. International Journal of Greenhouse Gas Control. ISSN 1750-5836. 99. doi: 10.1016/j.ijggc.2020.103075. Fulltekst i vitenarkiv Vis sammendrag

  Carbon capture and storage (CCS) would contribute considerably towards climate change mitigation, if it would be implemented on a very large scale; at many storage sites with substantial injection rates. Achieving high injection rates in deep saline aquifers requires a detailed assessment of injectivity performance and evaluation of the processes that alter the permeability of the near-well region. One of the most common forms of the injectivity loss in the context of CO2 storage in saline aquifers is salt precipitation driven by the evaporation of brine into the relatively dry injected CO2 stream. We present a novel compositional transport formulation based on overall-composition variables which models salt as a separate solid phase which could potentially form through two essentially different ways, i.e., kinetic or equilibrium. To model formation drying-out and subsequent halite-precipitation, an accurate and reliable fluid model ePC-SAFT, which can effectively account for ionic effects, is applied. In addition, a volume balance approach (i.e., depending on how far the salt saturation is from the solubility limit) is implemented to estimate solid saturation in a simulation cell. The resulting simulator is benchmarked against several well-known examples, with analytical solutions demonstrating the ability of the code to cover a variety of physical mechanisms. Finally, injection of dry CO2 into a brine-saturated core-scale domain is simulated and sensitivity analyses over various parameters are performed. We show that the new model is capable to quantitatively represent the physics of salt precipitation (for example salt self-enhancing) under different reservoir conditions.

• Skurtveit, Elin; Sundal, Anja; Bjørnarå, Tore Ingvald; Soldal, Magnus; Sauvin, Guillaume & Zuchuat, Valentin [Vis alle 8 forfattere av denne artikkelen] (2020). Experimental investigation of natural fracture stiffness and flow properties in a faulted CO2 bypass system (Utah, USA). Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 125(7). doi: 10.1029/2019JB018917. Fulltekst i vitenarkiv Vis sammendrag

  Fracture stiffness and flow properties have been measured in the laboratory using naturally fractured fault rock samples from the Little Grand Wash fault, Utah, USA. We compare fracture closure and related flow change during isotropic loading of two fractures which have been subject to various amounts of paleo‐reactive flow. The two tested fractures are described as (i) a small‐aperture fracture (0.1 mm) with negligible geochemical alterations of the fracture surface and (ii) a large‐aperture fracture (0.53 mm) where precipitates are observed on the fracture surface. X‐ray imaging is used for quantification of fracture aperture and fracture surface contact distribution. The petrographical characterisation using scanning electron microscopy and x‐ray powder diffraction is performed pre‐test and describes burial and uplift diagenesis as well as pulses of reactive fluid flow within the fault. The stress dependent flow and deformation experiment provides new data on fracture stiffness and flow for naturally developed fractures in siliciclastic rock. Fracture stiffness is found to be highest for the small‐aperture fracture due to its high fracture contact ratio and well‐developed surface mating during closure. For the naturally altered and rougher, large‐aperture fracture, fracture stiffness is lower and a highly stress dependent decay in flow is observed during initial closure. The results illustrate that a natural fracture with high contact ratio and well mated surfaces will close during loading, whereas a fracture associated with high flow rates and affected by previous geochemical alteration maintains a high flow rate compared to the host rock during similar loading.

• Zuchuat, Valentin; Midtkandal, Ivar; More, Miquel Poyatos; Costa, Sigrid Da; Brooks, Hannah Louise & Halvorsen, Kristine [Vis alle 9 forfattere av denne artikkelen] (2019). Composite and diachronous stratigraphic surfaces in low-gradient, transitional settings: The J-3 “unconformity” and the Curtis Formation, east-central Utah, U.S.A. Journal of Sedimentary Research. ISSN 1527-1404. 89(11), s. 1075–1095. doi: 10.2110/jsr.2019.56. Fulltekst i vitenarkiv Vis sammendrag

  Unconformities, by definition, correspond to erosional or nondepositional surfaces, which separate older strata below, from younger rocks above, encapsulating significant time gaps. However, recent studies have highlighted the composite nature of some unconformities, as well as their heterochronous and diachronous character, which challenge the use of such a definition in a four-dimensional dynamic environment. The J-3 Unconformity, separating the Middle Jurassic Entrada Sandstone from the Upper Jurassic Curtis Formation (and laterally equivalent units) in east-central Utah (USA), is laterally variable, generated by either erosion-related processes such as eolian deflation, and water-induced erosion, or by deformational processes. The J-3 Unconformity is a composite surface, formed by numerous processes that interacted and overlapped spatially and temporally. This study therefore demonstrates the heterochronous, diachronous, and non-unique nature of this surface interpreted as unconformity, where one process can be represented by varying expressions in the stratigraphic record, and conversely many processes may result in the same stratigraphic expression.

• Sundal, Anja & Hellevang, Helge (2019). Using Reservoir Geology and Petrographic Observations to Improve CO2 Mineralization Estimates; Examples from the Johansen Formation, North Sea, Norway. Minerals. 9(11). doi: 10.3390/min9110671. Fulltekst i vitenarkiv Vis sammendrag

  Reservoir characterization specific to CO2 storage is challenging due to the dynamic interplay of physical and chemical trapping mechanisms. The mineralization potential for CO2 in a given siliciclastic sandstone aquifer is controlled by the mineralogy, the total reactive surface areas, and the prevailing reservoir conditions. Grain size, morphologies and mineral assemblages vary according to sedimentary facies and diagenetic imprint. The proposed workflow highlights how the input values for reactive mineral surface areas used in geochemical modelling may be parameterized as part of geological reservoir characterization. The key issue is to separate minerals both with respect to phase chemistry and morphology (i.e., grain size, shape, and occurrence), and focus on main reactants for sensitivity studies and total storage potentials. The Johansen Formation is the main reservoir unit in the new full-value chain CO2 capture and storage (CCS) prospect in Norway, which was licenced for the storage of CO2 as of 2019. The simulations show how reaction potentials vary in different sedimentary facies and for different mineral occurrences. Mineralization potentials are higher in fine-grained facies, where plagioclase and chlorite are the main cation donors for carbonatization. Reactivity decreases with higher relative fractions of ooidal clay and lithic fragments.

• Olivarius, Mette; Sundal, Anja; Weibel, Rikke; Gregersen, Ulrik; Baig, Irfan & Thomsen, T.B. [Vis alle 9 forfattere av denne artikkelen] (2019). Provenance and sediment maturity as controls on CO2 mineral sequestration potential of the Gassum Formation in Skagerrak. Frontiers in Earth Science. 7. doi: 10.3389/feart.2019.00312. Fulltekst i vitenarkiv Vis sammendrag

  In order to meet the increasing demand to decarbonize the atmosphere, storage of CO2 in subsurface geological reservoirs is an effective measure. To maximize storage capacity, various types of saline aquifers should be considered including dynamic storage options with open or semi-open boundaries. In sloping aquifers, assessment of the immobilization potential for CO2 through dissolution and mineralization along the flow path is a crucial part of risk evaluations. The Gassum Formation in the Skagerrak is considered a nearshore CO2 storage option with sloping layers, facilitating buoyant migration of CO2 northwards along depositional and structural dip. In this study, petrographic data and provenance analysis provide the basis for estimating reactivity of the sandstones. Immobilization of CO2 in the reservoir through fluid dissolution and mineral reactions reduces risk of leakage. Petrographic analyses are integrated with seismic and well-log interpretation to identify sedimentary facies and to estimate mineral distribution with corresponding reactivity in the proposed injection area. Here the Gassum Formation comprises south-prograding, shoreface-fluvial para-sequences, sourced from northern hinterlands. Pronounced differences in the mineralogical maturity in the studied area are identified and explained by the sediment transport distances and the type of sediment source. This is possible because the U-Pb ages of zircon grains in the sediments can be used to pinpoint the areas where they originate from in the Fennoscandian Shield, such as the Telemarkia or Idefjorden terranes. Albite and Fe-rich chlorite are identified as the most reactive mineral phases in the Gassum sand, of which feldspar comprises the largest weight fraction and the grain-coating chlorite has largest surface area. Their distribution is partly controlled by provenance, so their abundance decreases basinwards with increasing sediment maturity. The abundance of fluvial sandstones presumably increases northwards in basal parts of para-sequences, while shoreface sandstones comprise the top part of sandy units. CO2 injected in the proposed area will migrate upwards within the reservoir, toward higher proportions of Telemarkian-derived sediment and up-dip along the seal, toward more immature sediments. Thus, the reactivity of sediments increases in younger deposits and up depositional dip, while kinetic reaction rates will decrease in shallower, lower temperature regions. Identifying these parameters is important to estimate the CO2 mineral sequestration potential as a function of sedimentary facies and ensure safe storage of CO2. This approach can advantageously be applied to all reservoirs considered for CO2 injection to improve the estimation of the possible CO2 storage volume by taking the provenance dependence of the mineralization potential into account.

• Sundal, Anja; Brennwald, Matthias S.; Aagaard, Per & Kipfer, Rolf (2019). Noble gas composition and 3H/3He groundwater ages in the Gardermoen Aquifer, Norway: Improved understanding of flow dynamics as a tool for water management. Science of the Total Environment. ISSN 0048-9697. 660, s. 1219–1231. doi: 10.1016/j.scitotenv.2018.12.456. Fulltekst i vitenarkiv
• Elenius, Maria; Skurtveit, Elin; Yarushina, Viktoriya M.; Baig, Irfan; Sundal, Anja & Wangen, Magnus [Vis alle 13 forfattere av denne artikkelen] (2018). Assessment of CO2 storage capacity based on sparse data: Skade Formation. International Journal of Greenhouse Gas Control. ISSN 1750-5836. 79, s. 252–271. doi: 10.1016/j.ijggc.2018.09.004. Fulltekst i vitenarkiv Vis sammendrag

  Large North Sea aquifers of high quality are the likely major target for 12 Gt of European CO2 emissions that should be stored in the subsurface by 2050. This involves an upscaling of the present combined injection rate from all European projects, which requires careful examination of the storage feasibility. Many aquifers are closed or semi-closed, with storage capacity mainly constrained by consideration of caprock failure criteria. Because the induced overpressure can propagate to sensitive regions far from the injector, the risk of caprock failure must be examined in terms of large volumes and for long times. This poses challenges with respect to fluid-flow simulation in the presence of highly uncertain aquifer properties. In this work, experts on geology, geophysics, geomechanics and simulation technique collaborate to optimize the use of existing data in an efficient simulation framework. The workflow is applied to the large North Sea Skade Formation, with potential for secondary storage and pressure dissipation in the overlying Utsira Formation. Injection at three locations in Skade gives an overall practical capacity of 1–6 Gt CO2 injected over a 50-year period, depending on the reservoir permeability and compressibility. The capacity is limited by local pressure buildup around wells for the lowest estimated reservoir permeability, and otherwise by regional pressure buildup in shallow zones far from the injection sites. Local deformation of clay due to viscoelastoplastic effects do not have an impact on leakage from the aquifer, but these effects may modify the properties of clay layers within the aquifer, which reduces the risk of lateral compartmentalization. Uplift of the seafloor does not impose constraints on the capacity beyond those set by pressure buildup.

• Skurtveit, Elin; Braathen, Alvar; Larsen, Eivind Bernhard; Sauvin, Guillaume; Sundal, Anja & Zuchuat, Valentin (2017). Pressure Induced Deformation and Flow Using CO2 Field Analogues, Utah. Energy Procedia. 114, s. 3257–3266. doi: 10.1016/j.egypro.2017.03.1457. Fulltekst i vitenarkiv Vis sammendrag

  Exhumed reservoirs providing evidence of CO2 accumulation and transport in geological history offer a unique possibility to supplement our knowledge on leakage processes observed along faults and fractures. A field location and drill core from Central Utah, USA has been used to characterize mechanical properties and fracture distributions in multiple reservoir-caprock couplets where bleaching pattern around fractures provides evidence of fluid flow. Analysis shows that fractures are mainly observed in low porosity units corresponding to layers with high strength and stiffness. Microstructural characterization substantiates evidence of fracture aperture separated by areas with mineral precipitation clogging aperture. Minerals observed filling fractures are calcite, gypsum and pyrite, suggestive of precipitation from reducing fluids. Fracture aperture distribution and identification of mineralogical changes along the fracture surface provides important input for improved, novel analyses of CO2 transport properties of fractures and faults.

Se alle arbeider i NVA

• Holden, Nora; Alaei, Behzad; Skurtveit, Elin; Braathen, Alvar; Midtkandal, Ivar & Osmond, Johnathon L. [Vis alle 8 forfattere av denne artikkelen] (2024). CO2 storage on the Horda Platform - Assessing structural complexities and fault-seal integrity. Fulltekst i vitenarkiv
• Holden, Nora; Skurtveit, Elin; Braathen, Alvar; Alaei, Behzad; Midtkandal, Ivar & Osmond, Johnathon L. [Vis alle 8 forfattere av denne artikkelen] (2024). CO2 storage on the Horda Platform. Fulltekst i vitenarkiv
• Holden, Nora; Alaei, Behzad; Skurtveit, Elin; Braathen, Alvar; Midtkandal, Ivar & Osmond, Johnathon L. [Vis alle 8 forfattere av denne artikkelen] (2024). Structural de-risking of CO2 storage sites on the Horda Platform. Fulltekst i vitenarkiv
• Skurtveit, Elin; Petrie, Elizabeth S.; Smith, Scott Adam; Faleide, Thea Sveva; Sundal, Anja & Choi, Jung Chan [Vis alle 10 forfattere av denne artikkelen] (2023). Core analysis from Little Grand Wash fault, Utah, and application for fault risk assessment for co2 storage in the Norwegian North Sea. Fulltekst i vitenarkiv Vis sammendrag

  Fault zones contain a mixture of lithologies, various fault structures, and evidence for fluid-rock interaction events, representing a record of multiple deformation events during the faulting history. The resulting complex and highly variable mixture of properties makes faults challenging structures to model, and specifically assessing the fault zone permeability and probability of reactivation is difficult. The ability of fault zones to transport fluids has received renewed attention during the last 10 years of developing subsurface, geological storage reservoirs for CO2. The North Sea sedimentary basin offshore Norway has an enormous potential for storing CO2. However, to qualify fault traps in saline aquifers for storage, improved workflows for fault risk assessment focusing on fault zone flow properties and mechanical stability is needed. An improved approach for fault modelling is under development: we quantify the uncertainties in fault rock properties to address the probability of failure and subsequent changes in permeability. To support our understanding of subsurface faults in the North Sea, we utilize knowledge from the Little Grand Wash (LGW) fault, located in Emery County, Utah. The LGW fault zone provides a natural laboratory to study fault zone development in geological analogues, failure mechanisms, and fluid migration. As a supplement to already published well data and core descriptions from this area, three new cores were retrieved from the fault in 2019. In total 16.5 meters of core, covering both the hanging wall (Jurassic Brushy Basin Member of the Morrison Formation) and footwall (Jurassic Summerville Formation) damage zone, have been logged and sampled for petrophysical analysis and mechanical testing. The current work presents new data on variation of permeability, porosity, strength, and sonic velocity inside the fault damage zone, including measurements on different lithologies, various types of cementation and selected deformation bands, fractures, and veins. Petrophysical and chemical analysis combined with visual identification of oil stains and bleaching provide the possibility for a holistic understanding of the system and we derive valuable knowledge for improving fault risk workflows applicable for CO2 storage projects in the Norwegian North Sea.

• Holden, Nora; Osmond, Johnathon L.; Mulrooney, Mark Joseph; Skurtveit, Elin; Sundal, Anja & Braathen, Alvar (2023). Structural characterization and across-fault seal assessment of the Aurora CO2 storage site. Fulltekst i vitenarkiv
• Holden, Nora; Osmond, Johnathon; Mulrooney, Mark Joseph; Skurtveit, Elin; Braathen, Alvar & Sundal, Anja (2022). Influence of faults on Co2 migration. Fulltekst i vitenarkiv
• Holden, Nora; Osmond, Johnathon L.; Mulrooney, Mark Joseph; Skurtveit, Elin; Braathen, Alvar & Sundal, Anja (2022). Structural characterization and across-fault seal assessment of the Aurora CO2 storage site, northern North Sea. Fulltekst i vitenarkiv
• Holden, Nora; Osmond, Johnathon L.; Mulrooney, Mark Joseph; Skurtveit, Elin; Braathen, Alvar & Sundal, Anja (2022). Structural characterization and across-fault seal assessment of the Aurora CO2 storage site, northern North Sea. Fulltekst i vitenarkiv
• Weber, Ulrich Wolfgang; Kampman, Niko; Mikoviny, Tomas; Thomassen, Jorgen & Sundal, Anja (2021). Noble Gases as Monitoring Tracers in CCS: A Case study with CO2 from the Waste-To-Energy Plant Klemetsrud, Norway. Fulltekst i vitenarkiv
• Sundal, Anja (2021). Hydrogeologi “sett” fra verdensrommet – bruk av satellittdata I forvaltning og til overvåking av grunnvannsressurser. Fulltekst i vitenarkiv
• Sundal, Anja; Meneguolo, Renata & Hellevang, Helge (2021). CO2 storage – dynamic trapping mechanisms due to mineralization. Fulltekst i vitenarkiv
• Zuchuat, Valentin; Midtkandal, Ivar; More, Miquel Poyatos; Costa, Sigrid Da; Brooks, Hannah Louise & Halvorsen, Kristine [Vis alle 9 forfattere av denne artikkelen] (2021). Mind The Gap: Composite and diachronous stratigraphic surfaces in low-gradient, transitional settings: The J-3 “unconformity” and the Curtis Formation, east-central Utah, U.S.A. Fulltekst i vitenarkiv
• Holden, Nora; Osmond, Johnathon L.; Mulrooney, Mark Joseph; Sundal, Anja & Skurtveit, Elin (2021). Structural characterization of the Aurora prospect, a potential CO2 storage site in the northern North Sea. Fulltekst i vitenarkiv Vis sammendrag

  Significant uncertainties occur through varying methodologies when interpreting faults using seismic data. These uncertainties are carried through to the interpretation of how faults may act as baffles/barriers or increase fluid flow. How fault segments are picked when interpreting structures, i.e. what seismic line spacing is specified, as well as what surface generation algorithm is used, will dictate how detailed the surface is, and hence will impact any further interpretation such as fault seal or fault growth models. We can observe that an optimum spacing for fault interpretation for this case is set at approximately 100 m. It appears that any additional detail through interpretation with a line spacing of ≤50 m simply adds further complexities, associated with sensitivities by the individual interpreter. Hence, interpreting at a finer scale may not necessarily improve the subsurface model and any related analysis, but in fact lead to the production of very rough surfaces, which impacts any further fault analysis. Interpreting on spacing greater than 100 m often leads to overly smoothed fault surfaces that miss details that could be crucial, both for fault seal as well as for fault growth models. This contribution is a case example showing how different picking strategies influence analysis of a bounding fault in terms of CO2 storage assessment. This is an example from the Horda Plaform: the Smeaheia potential storage site, 20 km East of Troll East. This is a fault bound prospect, and hence this bounding fault is required to have a high seal potential and a low chance of reactivation upon CO2 injection, increasing the pore pressure. Uncertainty in the seismic interpretation methodology will follow through to fault seal analysis, specifically for analysis of whether in situ stresses combined with increased pressure through CO2 injection will act to reactivate the faults, leading to up-fault fluid flow / seep. We have shown that changing picking strategies significantly alter the interpreted stability of the fault, where picking with an increased line spacing has shown to increase the overall fault stability. Surprisingly, differences in picking strategy show little influence on the overall fault seal (i.e. shale gouge ratio) of the fault.

• Holden, Nora; Osmond, Johnathon L.; Mulrooney, Mark Joseph; Skurtveit, Elin; Braathen, Alvar & Sundal, Anja (2021). Structural characterization and across-fault seal assessment of the Aurora CO2 storage site. Fulltekst i vitenarkiv
• Sundal, Anja & Weber, Ulrich Wolfgang (2021). Applicability of noble gas tracers in Norwegian CO2 capture and storage schemes. The ICO2P project. Fulltekst i vitenarkiv
• Holden, Nora; Osmond, Johnathon L.; Mulrooney, Mark Joseph; Skurtveit, Elin; Braathen, Alvar & Sundal, Anja (2021). Structural characterization and across-fault seal assessment of the Aurora CO2 storage site, northern North Sea. Fulltekst i vitenarkiv
• Holden, Nora; Osmond, Johnathon L.; Mulrooney, Mark Joseph; Skurtveit, Elin; Braathen, Alvar & Sundal, Anja (2021). Across-fault seal assessment of the Aurora CO2 storage site, northern North Sea. Fulltekst i vitenarkiv
• Sundal, Anja (2021). Design of a mobile, cost-effective monitoring tool for CO2 storage sites on the Norwegian shelf. Fulltekst i vitenarkiv
• Sundal, Anja & Weber, Ulrich Wolfgang (2021). Applicability of noble gas tracers in Norwegian CO2 capture and storage schemes. Fulltekst i vitenarkiv
• Sundal, Anja; Meneguolo, Renata; Kruber, Claudia; Olsen, Elin & Hellevang, Helge (2021). Geological site assessment: geochemical review of the Aurora Storage Complex, Northern Lights project, North Sea. Fulltekst i vitenarkiv
• Sundal, Anja; Aage, Stangeland & Bru, Tina (2021). Fra lab til langskip. [Internet]. www.youtube.com/watch?v=9BcR6SFCUTg. Fulltekst i vitenarkiv Vis sammendrag

  Videoen "Fra lab til langskip" ble produsert av Gyro for Gassnova/CLIMIT, og presentert på CLIMIT Digit 10.02.2021 Tina Bru, Aage Stangeland og Anja Sundal intervjues. Videoen ligger tilgjengelig her: www.youtube.com/watch?v=9BcR6SFCUTg

• Weber, Ulrich Wolfgang; Sundal, Anja; Hellevang, Helge & Kipfer, Rolf (2020). Experiences from the ICO2P Project applied to Migration Monitoring of Injected CO2. Fulltekst i vitenarkiv
• Weber, Ulrich Wolfgang; Raphaug, Martin Hagen; Revheim, Maiken & Sundal, Anja (2020). Gas Composition of the Svelvik Ridge Aquifers Used to Design Noble Gas Tracers for a CO2 Injection Experiment. Fulltekst i vitenarkiv
• Weber, Ulrich Wolfgang; Heeschen, Katja; Zimmer, Martin; Raphaug, Martin Hagen; Hagby, Klaus Falk & Ringstad, Cathrine [Vis alle 7 forfattere av denne artikkelen] (2020). Tracer Design and Gas Monitoring of a CO2 Injection Experiment at the ECCSEL CO2 Field Lab, Svelvik, Norway. Fulltekst i vitenarkiv
• Sundal, Anja (2020). Hvordan karbon kan lagres trygt i stein. Fulltekst i vitenarkiv
• Sundal, Anja (2020). Geologisk CO2-lagring – trygg og effektiv utslippsreduksjon. Fulltekst i vitenarkiv
• Sundal, Anja (2020). Prospectivity of noble gas tracers in CCS monitoring schemes. Fulltekst i vitenarkiv
• Andersen, Odd & Sundal, Anja (2020). Using 2D seismic line data to estimate the possible impact of large-scale and sub-scale structural trapping in the Gassum Formation on the Norwegian Continental Shelf. Fulltekst i vitenarkiv
• Zuchuat, Valentin; Midtkandal, Ivar; More, Miquel Poyatos; Costa, Sigrid Da; Brooks, Hannah L & Halvorsen, Kristine [Vis alle 9 forfattere av denne artikkelen] (2020). Brexit, Megxit, and the J-3 Unconformitexit: how they all lost it. Fulltekst i vitenarkiv Vis sammendrag

  Unconformities, by definition, correspond to non-depositional or erosive surfaces, separating older strata below, from younger rocks above, and encapsulating significant time gaps. However, recent studies have emphasized the composite nature of some unconformities, as well as their heterochronous and diachronous character, which restricts the use of such a definition to a near one-dimensional setting. This study analyses the nature of the J-3 Unconformity, which separates the Middle Jurassic Entrada Sandstone from the Late Jurassic Curtis Formation (and laterally equivalent units) in east-central Utah (USA). Our detailed mapping and characterization indicates the J-3 “Unconformity” is in fact a composite surface generated by either erosion-related processes such as eolian deflation, and water-induced erosion, or by deformational processes. These multiple mechanisms interacted and overlapped in time and space, which demonstrates the composite and diachronous and non-unique nature of such boundaries. This contact has been historically interpreted as an unconformity, but our results show that this key stratigraphic surface is a time-transgressive flooding-ravinement surface that formed shortly before and during a series of transgressions that flooded the area during the Late Jurassic. Consequently, the regionally extensive, composite, heterochronous, and diachronous J-3 Unconformity does not fit the classic unconformity definition, after which an unconformity universally separates older from younger strata basin-wide. The J3 “Unconformity” case study highlights the fact that one process can be represented by varying expressions in the stratigraphic record, and conversely many processes may result in the same stratigraphic expression. Consequently a revised definition of unconformity is discussed, focusing on processes and associated environmental changes, while abandoning its time-barrier aspect. This investigation also exemplifies some of the implications on subsurface analyses that the inaccurate characterization of the subseismic complex characters of such major stratigraphic bounding surfaces can have. These inaccuracies may lead to imprecise timing and sediment budget predictions, and ultimately have strong implications for basin evolution and reservoir models. Key words: Unconformity, transitional basin, composite surface, ravinement, time-transgressive

• Zuchuat, Valentin; Hafner, Alison; Osmond, Johnathon L.; Liberty, Lee; Petrie, Elizabeth & Arvesen, Brock [Vis alle 11 forfattere av denne artikkelen] (2020). CO2 containment and monitoring techniques along Little Grand Wash Fault, east-central Utah, USA. Fulltekst i vitenarkiv Vis sammendrag

  Our current understanding of sub-surface CO2 storage feasibility derives mainly from valuable small-scale projects, which have mostly been working at injection or human time scales. These projects, however, have not been operational long enough to fully assess flow and/or seepage at longer time scales relevant for subsurface CO2 sequestration (e.g. > 10 kY). Many examples of fluid escape have been documented in the offshore subsurface environment (e.g. seismic chimneys), and active or relict natural seeps on land offer informative analogues to subsurface fluid migration. Of note are the natural seeps located in east-central Utah, USA that are easily accessible and represent suitable onshore counterparts to the offshore fluid escape features. These seeps can be studied to improve our understanding of geological and geomechanical factors controlling subsurface CO2 containment and the expression of fluid escape in geophysical images. A critical concern in CCS is how to account for features that are detrimental to subsurface storage containment and are at scales below seismic resolution. This multidisciplinary project aims to address the challenge by collecting surface and subsurface datasets at mesoscopic scales that, through upscaling, will be implemented in seismic investigations and reservoir-seal models. The project builds upon previous studies detailing the complex development of the Jurassic sedimentary basin in question (Zuchuat et al. 2018; 2019a; 2019b) but is also relevant for analogous settings such as the Norwegian Continental Shelf (e.g. Horda Platform region). Overall, this next research phase specifically focuses on the detailed, post-depositional history of the targeted interval in Utah, addressing one fundamental question: what are the thresholds for detecting CO2 seeps in the subsurface? This encompasses more targeted questions: • What does the fault core and the fault damage zone of the leaking Little Grand Wash Fault consist of? • What is the detailed geological footprint of CO2 flow along strata, faults, and fractures? • How did the CO2 flow migrate through a heterogeneous and transitional, faulted reservoir-seal complex? • Can seepage from the storage compartments and fluid saturation be identified by seismic imaging? Zuchuat, V., Sleveland, A. R., Sprinkel, D. A., Rimkus, A., Braathen, A., & Midtkandal, I. (2018). New Insights on the Impact of Tidal Currents on a Low-gradient, Semi-enclosed, Epicontinental Basin—the Curtis Formation, East-central Utah, USA. Geology of the Intermountain West, 5, 131-165. Zuchuat, V., Sleveland, A.R.N., Pettigrew, R.P, Dodd, T.J.H., Clarke, S.M., Braathen, A., & Midtkandal, I. (2019a). Overprinted Allocyclic Processes by Tidal Resonance in an Epicontinental Basin: the Upper Jurassic Curtis Formation, East-Central Utah, USA. The Depositional Record, 5(2), 272-305. Zuchuat, V., Midtkandal, I., Poyatos-Moré, M., Da Costa, S., Brooks, H.L., Halvorsen, K., Cote, N., Sundal, A., & Braathen, A. (2019b). Composite and Diachronous Stratigraphic Surfaces in Low-Gradient, Transitional Settings: the J-3 “Unconformity” and the Curtis Formation, East-Central Utah, U.S.A. Accepted in The Journal of Sedimentary Research.

• Sundal, Anja; Weber, Ulrich Wolfgang; Kürschner, Wolfgang; Grimstad, Alv Arne; Ruden, Fridtjof & Aagaard, Per [Vis alle 9 forfattere av denne artikkelen] (2020). Hydrogeological characterization of Holocene deposits in the Svelvik aquifer – implications for reservoir properties. Fulltekst i vitenarkiv
• Revheim, Maiken Kristiansen; Weber, Ulrich Wolfgang; Hagby, Klaus Falk; Ringstad, Cathrine & Sundal, Anja (2020). Tidal effect on pressure in upper and lower aquifer of the Svelvik Ridge. Fulltekst i vitenarkiv
• Røyne, Anja; Samset, Bjørn Hallvard; Sundal, Anja; Storelvmo, Trude & Joner, Erik (2020). Boklansering: Varm klode, kaldt hode. Løsninger på klimakrisen. Fulltekst i vitenarkiv
• Sundal, Anja (2020). Geologisk lagring av CO2. Fulltekst i vitenarkiv Vis sammendrag

  Foredragene ble filmet, og ligger tilgjengelige her: https://youtu.be/o5AwDGwjIns

• Sundal, Anja & Ruden, Fridtjof (2019). CO2-lagring i grunnen – hydrogeologisk feltlaboratorium på Svelvik. Fulltekst i vitenarkiv Vis sammendrag

  Event: https://facebook.com/events/2159455514177753/?ti=cl

• Sundal, Anja (2019). Application of noble gas signatures in monitoring schemes for CO2 storage offshore Norway. Fulltekst i vitenarkiv Vis sammendrag

  Short (1 slide) pitch about the ICO2P project

• Sundal, Anja (2019). Geologisk lagring av CO2 på norsk sokkel. Fulltekst i vitenarkiv
• Sundal, Anja (2019). Geologisk CO2-lagring – trygt og godt for alltid? Fulltekst i vitenarkiv Vis sammendrag

  Program: https://www.uio.no/om/samarbeid/skole/fagped-dag/program/

• Sundal, Anja (2019). Hydrogeology of the Svelvik CO2-Field lab. Fulltekst i vitenarkiv Vis sammendrag

  Program: https://www.sintef.no/projectweb/svelvik-co2-field-lab/nyheter/svelvik-opening/

• Sundal, Anja (2019). Safe storage of CO2. Fulltekst i vitenarkiv
• Sundal, Anja (2019). Cost-effective monitoring by application of noble gas signatures. Fulltekst i vitenarkiv
• Sundal, Anja (2019). GEO-onsdag: Geologisk CO2-lagring – trygt og godt for alltid? Fulltekst i vitenarkiv Vis sammendrag

  Foredraget er publisert på nett: https://www.youtube.com/watch?v=artSoVqp-F0

• Weber, Ulrich Wolfgang; Kipfer, Rolf; Brennwald, Matthias S.; Ringrose, Philip & Sundal, Anja (2019). Noble Gases as Monitoring Tracers: Sampling Campaigns at Capture Sites Technology Center Mongstad and Melkøya. Fulltekst i vitenarkiv
• Sena, Clara; Sundal, Anja; Uglum, Maria C.; Kristiansen, Ingrid E. & Kvitsjøen, Julia (2019). Hydrogeological tools in urban runoff management – case study from Torshovdalen, Oslo. Fulltekst i vitenarkiv
• Sundal, Anja; Tuttle, Kevin J.; Aagaard, Per; Fikse, Andrea Nymoen; Moe, K.G. & Øvstedal, Jarl (2019). Managing and monitoring dynamic ravinement processes. Fulltekst i vitenarkiv
• Sundal, Anja; Miri, Rohaldin; Andersen, Odd; Hellevang, Helge; Gregersen, Ulrik & Olivarius, Mette [Vis alle 14 forfattere av denne artikkelen] (2019). Optimized CO2 storage in sloping aquifers: Estimation of physical and chemical immobilization potential and retardation along migration path in open storage solutions. Fulltekst i vitenarkiv
• Aagaard, Per; Sena, Clara; Sundal, Anja & French, Helen Kristine (2019). In situ removal of iron and manganese, the Vyredox treatment system at Elverum. Fulltekst i vitenarkiv
• Sundal, Anja; French, Helen Kristine & Aagaard, Per (2019). Hydrogeology for students and society: outreach integration in education. Fulltekst i vitenarkiv
• Anell, Ingrid Margareta; Backer, Dag; Sundal, Anja; Torvanger, Asbjørn; Meisingset, Egil & Rørvik, Kari-Lise [Vis alle 7 forfattere av denne artikkelen] (2019). Feasibility of CO2 storage as a climate mitigation measure in Norway. Fulltekst i vitenarkiv
• Zuchuat, Valentin; Osmond, Johnathon L.; Sundal, Anja; Midtkandal, Ivar; Skurtveit, Elin & Petrie, Elizabeth [Vis alle 9 forfattere av denne artikkelen] (2019). CO2 containment and monitoring techniques along Little Grand Wash Fault, east-central Utah, USA. Fulltekst i vitenarkiv Vis sammendrag

  Our current understanding of sub-surface CO2 sequestration feasibility derives mainly from valuable small-scale projects, which have mostly been working at injection or human time scales. These projects, however, have not been operational long enough to fully assess flow and/or seepage at longer time scales relevant for subsurface CO2 storage (e.g. > 10 kY). Many examples of fluid escape have been documented in the offshore subsurface environment (e.g. seismic chimneys), and natural seeps found on land, both active and relict, offer informative analogues to subsurface fluid migration. Of note are the natural seeps located in east-central Utah, USA that are easily accessible and represent suitable onshore counterparts to the offshore fluid escape features. These seeps can improve our understanding of geological and geomechanical factors controlling subsurface CO2 containment and the expression of fluid escape in geophysical images. A critical concern is how to account for features that are detrimental to subsurface storage containment and are at scales below seismic resolution. This multidisciplinary project aims to address the challenge by collecting surface and subsurface datasets at mesoscopic scales that, through viable upscaling, will be implemented in seismic investigations and reservoir-seal models. Moreover, the project builds upon previous studies detailing the complex development of the Jurassic sedimentary basin in question (Zuchuat et al. 2018; 2019; in press) but is also relevant for the Horda Platform region (Aurora and Smeaheia) or other prospective North Sea CO2 storage sites. Overall, this next research phase specifically focuses on the detailed, post-depositional history of the targeted interval in Utah, addressing one fundamental question: what are the thresholds for detecting CO2 seeps in the subsurface? This encompasses more targeted questions: • What is the detailed geological footprint of CO2 flow along strata, faults, and fractures? • How did the CO2 flow migrate through a heterogeneous and transitional, faulted reservoir-seal complex? • Can seepage from the storage compartment be identified by seismic imaging? • Can detailed geological datasets and related geophysical models verify the existence of – and facilitate quantification of CO2 volumes (saturation) required to create offshore geophysical chimneys, and thereby improve integrity assessment of prospective North Sea CO2 reservoirs? Zuchuat, V., Sleveland, A. R., Sprinkel, D. A., Rimkus, A., Braathen, A., & Midtkandal, I. (2018). New Insights on the Impact of Tidal Currents on a Low-gradient, Semi-enclosed, Epicontinental Basin—the Curtis Formation, East-central Utah, USA. Geology of the Intermountain West, 5, 131-165. Zuchuat, V., Sleveland, A.R.N., Pettigrew, R.P, Dodd, T.J.H., Clarke, S.M., Braathen, A., & Midtkandal, I. (2019). Overprinted Allocyclic Processes by Tidal Resonance in an Epicontinental Basin: the Upper Jurassic Curtis Formation, East-Central Utah, USA. The Depositional Record, 5(2), 272-305. Zuchuat, V., Midtkandal, I., Poyatos-Moré, M., Da Costa, S., Brooks, H.L., Halvorsen, K., Cote, N., Sundal, A., & Braathen, A. (in press.). Composite and Diachronous Stratigraphic Surfaces in Low-Gradient, Transitional Settings: the J-3 “Unconformity” and the Curtis Formation, East-Central Utah, U.S.A. Accepted in The Journal of Sedimentary Research.

• Weber, Ulrich Wolfgang & Sundal, Anja (2019). Application of noble gas signatures in monitoring schemes for offshore CO2 storage (ICO2P). Fulltekst i vitenarkiv
• Weber, Ulrich Wolfgang; Sundal, Anja; Brennwald, M.S. & Kipfer, Rolf (2019). Temporal Variation in Noble Gas Signatures of Captured CO2. Fulltekst i vitenarkiv
• Andersen, Odd & Sundal, Anja (2019). Using 2D seismic line data to estimate impact of caprock morphology on CO2 migration in the Gassum formation. Fulltekst i vitenarkiv Vis sammendrag

  The Gassum Formation on the Norwegian Continental Shelf serves as the principal case study for the CO2-Upslope project. The top surface of this formation is gently sloping, and characterized by a number of macro-scale structural traps, a few large faults, a large number of small faults, and small-scale depth variations that can be inferred and extrapolated from the seismic data. In the study presented in this paper, we estimate the amount of macro- and sub-scale trapping potential of the formation based on interpreted 2D seismic lines and identified faults. The seismic lines provide the depth of the caprock at each point along straight lateral paths. In the available data, a few dozen such lines cross the study area at various angles. A number of medium and large faults could be explicitly identified and mapped, as they correlate between several of these lines. In addition, hundreds of small-scale faults are only visible as discontinuities along individual lines. The extent and shape of these small faults between the seismic sections cannot be explicitly known from the data. In order to investigate trapping potential, we start out by constructing multiple realizations of the top surface, constructed to be faithful to both large-scale topography and small-scale statistical properties. We use a tensor spline surface approximation to represent the surface trend, with added stochastic small-scale variations consistent with the statistical properties of the line data. Moreover, we include a distribution small-scale faults that are only visible as discontinuities in the seismic lines by adding assumptions on their general orientations and lengths. At the timescales associated with long-term CO2 plume migration, it can generally be assumed that vertical equilibrium has been reached and that the CO2 slowly flows as a thin wedge right under the top surface, driven by gravity forces. Based on this assumption, we apply spill-point analysis and upscaling techniques on our sets of top surface realizations to explore the possible range of values for total structural trapping and plume retardation potential, and how they depend on the assumptions made. We also study the impact of the placement of the injection site, and how much of the total structural storage potential can be actually realized based on the position of the site and the injection strategy.

• Kristiansen, Ingrid E.; Uglum, Maria C.; Sena, Clara; Sundal, Anja & Kvitsjøen, Julia (2018). ASSESSMENT OF THE URBAN RUNOFF AND GROUNDWATER QUALITY IN THE RECREATIONAL AREA OF TORSHOVDALEN (OSLO, NORWAY). Fulltekst i vitenarkiv
• Bromander, Nikoline; Costa, Sigrid da; Skurtveit, Elin; Evans, Jim; Midtkandal, Ivar & Zuchuat, Valentin [Vis alle 8 forfattere av denne artikkelen] (2018). Regional evaluation of structural collapse in sandstone reservoirs and impact on reservoir quality: a case study from the Entrada Sandstone, Utah, USA. Fulltekst i vitenarkiv
• Uglum, Maria C.; Sundal, Anja; Sena, Clara & Kvitsjøen, Julia (2018). CONSIDERING GROUNDWATER RECHARGE AND FLOW IN URBAN DEVELOPMENT PLANNING – A CASE STUDY FROM TORSHOVDALEN, OSLO. Fulltekst i vitenarkiv
• Sacco, Tatiana; Sundal, Anja & Hellevang, Helge (2018). Mass estimation of CO2 trapping potential in the Smeaheia reservoir. Fulltekst i vitenarkiv
• Gregersen, Ulrik; Baig, Irfan; Sundal, Anja; Nielsen, Lars-Henrik; Olivarius, Mette & Weibel, Rikke (2018). Seismic interpretation of a potential CO2 reservoir; the Gassum Formation, a sloping aquifer in Skagerrak between Norway and Denmark. Fulltekst i vitenarkiv
• Olivarius, Mette; Sundal, Anja; Gregersen, Ulrik; Thomsen, T.B.; Weibel, Rikke & Nielsen, Lars-Henrik (2018). Using petrography and provenance data to assess the CO2 trapping potential in sloping sandstones in the Skagerrak Strait. EAGE extended abstracts. doi: 10.3997/2214-4609.201801148. Fulltekst i vitenarkiv Vis sammendrag

  80th EAGE Conference and Exhibition 2018 CO2 Capture, Storage and Utilization http://www.earthdoc.org/publication/publicationdetails/?publication=92535

• Sundal, Anja; Hellevang, Helge; Olivarius, Mette; Miri, Rohaldin; Nielsen, Lars-Henrik & Gregersen, Ulrik [Vis alle 10 forfattere av denne artikkelen] (2018). Geological Constraints on the immobilization potential for CO2 in the Gassum Fm. (Skagerrak, Norway). Fulltekst i vitenarkiv
• Skurtveit, Elin; Sundal, Anja; Soldal, Magnus; Sauvin, Guillaume & Bjørnarå, Tore Ingvald (2018). CO2 flow, alteration and geomechanical response in confining units – An experimental approach. Fulltekst i vitenarkiv
• Kaufmann, Roland; Gasda, Sarah Eileen; Elenius, Maria; Skurtveit, Elin; Choi, Jung Chan & Braathen, Alvar [Vis alle 9 forfattere av denne artikkelen] (2018). Large-scale CO2-injection in Smeaheia. Fulltekst i vitenarkiv
• Kaufmann, Roland; Gasda, Sarah Eileen; Elenius, Maria; Skurtveit, Elin; Choi, Jung Chan & Sundal, Anja [Vis alle 9 forfattere av denne artikkelen] (2018). Arbeidsflyt for trykk-basert kapasitets-anslag: En eksempelstudie på Smeaheia. Fulltekst i vitenarkiv
• Zuchuat, Valentin; Midtkandal, Ivar; Miquel, Poyatos-More; Costa, Sigrid Da; Halvorsen, Kristine Årland & Sundal, Anja [Vis alle 8 forfattere av denne artikkelen] (2018). Unconformities matter: The spatial and temporal information contained in the J-3 Unconformity and the Curtis Formation, east-central Utah, USA. Fulltekst i vitenarkiv
• Sundal, Anja; Weber, Ulrich Wolfgang; Brennwald, Matthias S.; Ringrose, Philip; flø, nina enaasen & Johnsen, Kim [Vis alle 9 forfattere av denne artikkelen] (2018). Monitoring real time, in-line variations of noble gas concentrations during CO2 capture operations by means of a portable mass spectrometer. Fulltekst i vitenarkiv
• Grimstad, Alv-Arne; Sundal, Anja; Ringstad, Cathrine & Hagby, Klaus Falk (2018). Modelling medium-depth CO2 injection at the Svelvik CO2 field laboratory in Norway. Fulltekst i vitenarkiv
• Gasda, Sarah; Elenius, Maria; Skurtveit, Elin; Sundal, Anja; Yarushina, Viktoriya M. & Baig, Irfan [Vis alle 13 forfattere av denne artikkelen] (2018). Skade Case Study. Fulltekst i vitenarkiv
• Gregersen, Ulrik; Baig, Irfan; Sundal, Anja; Nielsen, Lars Henrik; Olivarius, Mette & Weibel, Rikke (2018). Seismic interpretation of a slopping offshore potential CO2 aquifer; the Gassum Formation in Skagerrak between Norway and Denmark. Fulltekst i vitenarkiv
• Midtkandal, Ivar; Sundal, Anja; Braathen, Alvar; Petrie, Elizabeth; Evans, James R. & Zuchuat, Valentin [Vis alle 10 forfattere av denne artikkelen] (2018). Project summary: CO2 seal bypass - a multidisciplinary approach to CO2 migration and storage. Fulltekst i vitenarkiv
• daCosta, Sigrid Østmo; Bromander, Nikoline; Zuchuat, Valentin; Braathen, Alvar; Sundal, Anja & Midtkandal, Ivar (2018). Topographic Development as a result of regional incision, faulting, and deposition at the onset of relative sea-level rise; The upper Entrada Sandstone and the lower Curtis Formation, Utah, USA. Fulltekst i vitenarkiv
• Weber, Ulrich Wolfgang; Sundal, Anja; Brennwald, M.S.; Ringrose, Philip; Aagaard, P. & Kipfer, Rolf (2018). CO2 Capture Processes Monitored with Noble Gas Measurements. Fulltekst i vitenarkiv Vis sammendrag

  In the ICO2P project [1] a monitoring scheme for carbon capture and storage is developed with the aim to use noble gases as signatures for capture products. One approach to capture CO2 is amine-based temperature swing absorption. During such processes there is a potential for depletion of radiogenic noble gases from the fossil source, due to the addition of a gas phase void of radiogenic noble gases. The influence on the noble gas fingerprints of such techniques is investigated by single, analysed samples with full isotope resolution. This is combined with in-line, continuous noble gas measurements with a portable mass spectrometer [2]. This is a new approach that will provide knowledge of the uniqueness and temporal variations of noble gas fingerprints in the product stream from CO2 capture operations. The feasibility of such an on-site measurement system was successfully tested at a CO2 capture testing facility in Norway (TCM). Matching of the data with the reservoir source combusted at that time, forms the basis for setting up geochemical analytical schemes in mixing scenarios. Monitoring data from CO2 product streams are key in designing leakage detection schemes for future storage sites.

• Sundal, Anja (2017). KARBONLAGRING: Undergrunn + CO2 = trygt. Fulltekst i vitenarkiv Vis sammendrag

  Bli inspirert av åtte lynpresentasjoner om FNs bærekraftmål #7: Ren energi til alle. https://www.studentevent.no/events/84583 Velkommen til en lærerik og sosial kveld på Kulturhuset. Ta gjerne med en venn eller kollega – arrangementet er åpent og gratis for alle. Øl får du kjøpt i baren. NYHET! Tekna X er vår nye populærvitenskapelige formidlingsserie av spennende temaer som opptar unge. Vi gjør det ukjente kjent i høyt tempo med en sosial ramme. Hvert innlegg varer maks 8 minutter som gir deg mye ny kunnskap på kort tid – også ting du ikke visste du lurte på.

• Elenius, Maria; Hellevang, Helge; Skurtveit, Elin; Yurushina, Viktoriya; Baig, Irfan & Sundal, Anja [Vis alle 12 forfattere av denne artikkelen] (2017). Workflow for assessment of storage based on sparse data: Skade. Fulltekst i vitenarkiv
• Elenius, Maria; Hellevang, Helge; Skurtveit, Elin; Yurushina, Viktoriya; Baig, Irfan & Sundal, Anja [Vis alle 12 forfattere av denne artikkelen] (2017). Storage feasibility in North Sea aquifers. Fulltekst i vitenarkiv
• Elenius, Maria; Hellevang, Helge; Skurtveit, Elin; Yurushina, Viktoriya; Baig, Irfan & Sundal, Anja [Vis alle 12 forfattere av denne artikkelen] (2017). Workflow for evaluation of large-scale CO2 storage feasibility: Skade. Fulltekst i vitenarkiv
• Harris, Sharon; Anell, Ingrid Margareta; Sundal, Anja; Braathen, Alvar & Faleide, J I (2019). The Tectono-Sedimentary Development of Smeaheia on the Horda Platform with a Focus on the Cretaceous, and Implications for CO2 Storage. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Smeaheia is a proposed site for long-term storage of CO2. The site is located on the Horda Platform off the western coast of Norway, situated between the Vette and Øygarden Faults. The burial and uplift history of a basin has significant implications for reservoir and overburden properties. The uplift history of Norway is complex and consists of several phases, and the offshore basins have been linked to this development along with undergoing anomalous subsidence. This study aims to understand the depositional infill of the Smeaheia area with particular emphasis on the Cretaceous development, and how the uplift and subsidence history has affected the deposits with implications for CO2 storage. The study involves a detailed sedimentary analysis based primarily on seismic data (2D/3D) of the depositional successions on the Horda Platform, with a detailed focus on the Cretaceous sedimentary succession. The site-specific development of the area, based on the variations in sedimentary influx and the tilt and erosion of successions, is used to discuss the overburden properties of the storage site and influence on migration and secondary storage of CO2. In this study, Petrel (Schlumberger Ltd.) was used for the seismic interpretation of a 3D seismic cube and three 2D lines. 17 seismic horizons were mapped out, followed by the creation of RMS amplitude and time-thickness maps, which were used to evaluate depositional environments and sediment partitioning within the succession. The study is divided with respect to the Cretaceous, including an analysis of the Pre-Cretaceous, Cretaceous, and Post-Cretaceous development. The primary focus is on the Cretaceous Period, which consists of primarily fine-grained or clay-fraction sediments with some coarse-grained sediments near fault boundaries due to erosion on the edges of rotated fault blocks. The Cretaceous units represent the secondary reservoir of the potential CO2 storage site, Smeaheia, and are composed of shallow to deep marine mudstones with small amounts of sand. Units above the Alpha Structure of the primary Jurassic reservoir display homogeneity with more lithologic variation between the Vette and Øygarden Faults, while units above the Beta Structure are more varied and display more coarse-grained sediments. The Cretaceous units are in close contact with loosely compacted Quaternary sediments due to erosion along the Base Pleistocene Unconformity, which may be a potential leakage site should CO2 enter the secondary storage unit.

• Kolnes, Jens; Anell, i; Mulrooney, Mark Joseph; Veggeland, Frode & Faleide, J I (2019). Reconstruction of the Subsidence and Uplift History of a proposed CO2 Storage Site in the Northern North Sea. Universitetet i Oslo. Fulltekst i vitenarkiv
• Sundal, Anja; Hellevang, Helge & Sacco, Tatiana (2018). CO2 trapping in the Smeaheia reservoir – time mass estimation using geochemical models. Universitetet i Oslo. Fulltekst i vitenarkiv
• Elenius, Maria; Sundal, Anja; Gasda, Sarah; Aavatsmark, Ivar; Hellevang, Helge & Hermanrud, Christian [Vis alle 8 forfattere av denne artikkelen] (2018). Storage Capability [FME SUCCESS Synthesis report Volume 1]. SUCCESS [Christian Michelsen Research AS]. Fulltekst i vitenarkiv
• Bromander, Nikoline; Sundal, Anja; Midtkandal, Ivar & Zuchuat, Valentin (2018). Facies-controlled reservoir quality and preferential deformation in sandstone reservoirs; a case study from the Entrada Sandstone, Utah, USA. Universitetet i Oslo. Fulltekst i vitenarkiv
• Bromander, Nikoline; Sundal, Anja; Skurtveit, Elin; Midtkandal, Ivar & Braathen, Alvar (2018). Facies-controlled reservoir quality and preferential deformation in sandstone reservoirs; a case study from the Entrada Sandstone, Utah, USA. Universitetet i Oslo. Fulltekst i vitenarkiv

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