Anja Sundal

• 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.  s 1- 29 . doi: 10.1007/s11242-021-01622-1
• 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, s 1- 11 . doi: 10.1016/j.ijggc.2021.103376
• Weber, Ulrich Wolfgang; Kipfer, Rolf; Horstmann, Edith; Ringrose, Philip; Kampman, Niko; Tomonaga, Yama; Brennwald, M.S. & Sundal, Anja (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 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.

• Braathen, Alvar; Petrie, Elisabeth; Nystuen, Tonje; Sundal, Anja; Skurtveit, Elin; Zuchuat, Valentin; Gutierrez, Marte & Midtkandal, Ivar (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.
• 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.
• Skurtveit, Elin; Sundal, Anja; Bjørnarå, Tore Ingvald; Soldal, Magnus; Sauvin, Guillaume; Zuchuat, Valentin; Midtkandal, Ivar & Braathen, Alvar (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; Poyatos More, Miquel; Da Costa, Sigrid; Brooks, Hannah Louise; Halvorsen, Kristine; Cote, Nathan; Sundal, Anja & Braathen, Alvar (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.

• Olivarius, Mette; Sundal, Anja; Weibel, Rikke; Gregersen, Ulrik; Baig, Irfan; Thomsen, T.B.; Kristensen, Lars; Hellevang, Helge & Nielsen, Lars Henrik (2019). Provenance and sediment maturity as controls on CO2 mineral sequestration potential of the Gassum Formation in Skagerrak.. Frontiers in Earth Science.  ISSN 2296-6463.  7 . doi: 10.3389/feart.2019.00312 Fulltekst i vitenarkiv.
• 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
• 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.  ISSN 2075-163X.  9(11) . doi: 10.3390/min9110671 Fulltekst i vitenarkiv.
• Elenius, Maria; Skurtveit, Elin; Yarushina, Viktoriya M.; Baig, Irfan; Sundal, Anja; Wangen, Magnus; Landschulze, Karin; Kaufmann, Roland; Choi, Jung Chan; Hellevang, Helge; Podladchikov, Yuri; Aavatsmark, Ivar & Gasda, Sarah (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.

• Sundal, Anja; Miri, Rohaldin; Hellevang, Helge; Tveranger, Jan; Midtkandal, Ivar; Zuchuat, Valentin; Aagaard, Per & Braathen, Alvar (2017). Movement of CO 2 charged fluids in low permeability rocks during deformation: migration patterns in the Carmel Formation, Utah. Energy Procedia.  ISSN 1876-6102.  114, s 4537- 4544 . doi: 10.1016/j.egypro.2017.03.1570
• Bergmo, Per Eirik Strand; Emmel, Benjamin; Anthonsen, K.L.; Aagaard, Per; Mortensen, G M & Sundal, Anja (2017). Quality Ranking of the Best CO2 Storage Aquifers in the Nordic Countries. Energy Procedia.  ISSN 1876-6102.  114, s 4374- 4381 . doi: 10.1016/j.egypro.2017.03.1589 Fulltekst i vitenarkiv.
• 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.  ISSN 1876-6102.  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.

• Sundal, Anja; Nystuen, Johan Petter; Rørvik, Kari-Lise; Dypvik, Henning & Aagaard, Per (2016). The Lower Jurassic Johansen Formation, northern North Sea – Depositional model and reservoir characterization for CO2 storage. Marine and Petroleum Geology.  ISSN 0264-8172.  77, s 1376- 1401 . doi: 10.1016/j.marpetgeo.2016.01.021
• Sundal, Anja; Miri, Rohaldin; Ravn, Trude & Aagaard, Per (2015). Modelling CO2 migration in aquifers; considering 3D seismic property data and the effect of site-typical depositional heterogeneities. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  39, s 349- 365 . doi: 10.1016/j.ijggc.2015.05.021

Se alle arbeider i Cristin

• 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. 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.

• Zuchuat, Valentin; Midtkandal, Ivar; Poyatos More, Miquel; Da Costa, Sigrid; Brooks, Hannah Louise; Halvorsen, Kristine; Cote, Nathan; Sundal, Anja & Braathen, Alvar (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..
• Zuchuat, Valentin; Midtkandal, Ivar; Poyatos More, Miquel; Da Costa, Sigrid; Brooks, Hannah L; Halvorsen, Kristine; Sundal, Anja; Cote, Nathan & Braathen, Alvar (2020). Brexit, Megxit, and the J-3 Unconformitexit: how they all lost it.. 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

• 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.
• 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.
• Røyne, Anja; Samset, Bjørn Hallvard; Sundal, Anja; Storelvmo, Trude & Joner, Erik (2020). Boklansering: Varm klode, kaldt hode. Løsninger på klimakrisen.
• Sundal, Anja (2020). Geologisk CO2-lagring – trygg og effektiv utslippsreduksjon.
• Sundal, Anja (2020). Hvordan karbon kan lagres trygt i stein.
• Sundal, Anja (2020). Prospectivity of noble gas tracers in CCS monitoring schemes.
• Sundal, Anja; Weber, Ulrich Wolfgang; Kürschner, Wolfgang; Grimstad, Alv Arne; Ruden, Fridtjof; Aagaard, Per; Hagby, Klaus Falk; Revheim, Maiken Kristiansen & Ringstad, Cathrine (2020). Hydrogeological characterization of Holocene deposits in the Svelvik aquifer – implications for reservoir properties.
• Weber, Ulrich Wolfgang; Heeschen, Katja; Zimmer, Martin; Raphaug, Martin Hagen; Hagby, Klaus Falk; Ringstad, Cathrine & Sundal, Anja (2020). Tracer Design and Gas Monitoring of a CO2 Injection Experiment at the ECCSEL CO2 Field Lab, Svelvik, Norway.
• 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.
• Weber, Ulrich Wolfgang; Sundal, Anja; Hellevang, Helge & Kipfer, Rolf (2020). Experiences from the ICO2P Project applied to Migration Monitoring of Injected CO2.
• Zuchuat, Valentin; Hafner, Alison; Osmond, Johnathon L.; Liberty, Lee; Petrie, Elizabeth; Arvesen, Brock; Evans, Jim; Sundal, Anja; Midtkandal, Ivar; Skurtveit, Elin & Braathen, Alvar (2020). CO2 containment and monitoring techniques along Little Grand Wash Fault, east-central Utah, USA. 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; Miri, Rohaldin; Andersen, Odd; Hellevang, Helge; Gregersen, Ulrik; Olivarius, Mette; Nielsen, Lars Henrik; Møyner, Olav; Baig, Irfan; Heeremans, Michel; Lecomte, Isabelle; Nilsen, Halvor Møll; Frykman, Peter & Aagaard, Per (2019). Optimized CO2 storage in sloping aquifers: Estimation of physical and chemical immobilization potential and retardation along migration path in open storage solutions.
• Aagaard, Per; Sena, Clara; Sundal, Anja & French, Helen Kristine (2019). In situ removal of iron and manganese, the Vyredox treatment system at Elverum.
• Andersen, Odd & Sundal, Anja (2019). Using 2D seismic line data to estimate impact of caprock morphology on CO2 migration in the Gassum formation. 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.

• Anell, Ingrid Margareta; Backer, Dag; Sundal, Anja; Torvanger, Asbjørn; Meisingset, Egil; Rørvik, Kari-Lise & Øye, Olav (2019). Feasibility of CO2 storage as a climate mitigation measure in Norway.
• 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.
• 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.
• Sena, Clara; Sundal, Anja; Uglum, Maria C.; Kristiansen, Ingrid E. & Kvitsjøen, Julia (2019). Hydrogeological tools in urban runoff management – case study from Torshovdalen, Oslo.
• Sundal, Anja (2019). Application of noble gas signatures in monitoring schemes for CO2 storage offshore Norway. Vis sammendrag

  Short (1 slide) pitch about the ICO2P project

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

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

• Sundal, Anja (2019). Geologisk CO2-lagring – trygt og godt for alltid?. Vis sammendrag

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

• Sundal, Anja (2019). Geologisk lagring av CO2 på norsk sokkel.
• Sundal, Anja (2019). Hydrogeology of the Svelvik CO2-Field lab.. Vis sammendrag

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

• Sundal, Anja (2019). Safe storage of CO2.
• Sundal, Anja; French, Helen Kristine & Aagaard, Per (2019). Hydrogeology for students and society: outreach integration in education.
• Sundal, Anja & Ruden, Fridtjof (2019). CO2-lagring i grunnen – hydrogeologisk feltlaboratorium på Svelvik. Vis sammendrag

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

• Sundal, Anja; Tuttle, Kevin J.; Aagaard, Per; Fikse, Andrea Nymoen; Moe, K.G. & Øvstedal, Jarl (2019). Managing and monitoring dynamic ravinement processes.
• 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.
• Weber, Ulrich Wolfgang & Sundal, Anja (2019). Application of noble gas signatures in monitoring schemes for offshore CO2 storage (ICO2P).
• Weber, Ulrich Wolfgang; Sundal, Anja; Brennwald, M.S. & Kipfer, Rolf (2019). Temporal Variation in Noble Gas Signatures of Captured CO2.
• Zuchuat, Valentin; Osmond, Johnathon L.; Sundal, Anja; Midtkandal, Ivar; Skurtveit, Elin; Petrie, Elizabeth; Evans, Jim; Liberty, Lee & Braathen, Alvar (2019). CO2 containment and monitoring techniques along Little Grand Wash Fault, east-central Utah, USA. 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.

• Bromander, Nikoline; da Costa, Sigrid; Skurtveit, Elin; Evans, Jim; Midtkandal, Ivar; Zuchuat, Valentin; Braathen, Alvar & Sundal, Anja (2018). Regional evaluation of structural collapse in sandstone reservoirs and impact on reservoir quality: a case study from the Entrada Sandstone, Utah, USA.
• 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.
• 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..
• 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..
• Elenius, Maria; Sundal, Anja; Gasda, Sarah; Aavatsmark, Ivar; Hellevang, Helge; Hermanrud, Christian; Skurtveit, Elin & Midttømme, Kirsti (2018). Storage Capability [FME SUCCESS Synthesis report Volume 1].
• Gasda, Sarah; Elenius, Maria; Skurtveit, Elin; Sundal, Anja; Yarushina, Viktoriya M.; Baig, Irfan; Wangen, Magnus; Landschulze, Karin; Kaufmann, Roland; Choi, Jung Chan; Hellevang, Helge; Podladchikov, Yuri P. & Aavatsmark, Ivar (2018). Skade Case Study.
• 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.
• 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.
• Grimstad, Alv-Arne; Sundal, Anja; Ringstad, Cathrine & Hagby, Klaus Falk (2018). Modelling medium-depth CO2 injection at the Svelvik CO2 field laboratory in Norway.
• Kaufmann, Roland; Gasda, Sarah Eileen; Elenius, Maria; Skurtveit, Elin; Choi, Jung Chan; Braathen, Alvar; Mulrooney, Mark; Sundal, Anja & Wangen, Magnus (2018). Large-scale CO2-injection in Smeaheia.
• Kaufmann, Roland; Gasda, Sarah Eileen; Elenius, Maria; Skurtveit, Elin; Choi, Jung Chan; Sundal, Anja; Braathen, Alvar; Mulrooney, Mark & Wangen, Magnus (2018). Arbeidsflyt for trykk-basert kapasitets-anslag: En eksempelstudie på Smeaheia.
• 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).
• Midtkandal, Ivar; Sundal, Anja; Braathen, Alvar; Petrie, Elizabeth; Evans, James R.; Zuchuat, Valentin; Skurtveit, Elin; Tveranger, Jan; Torabi, Anita & Gutierrez, Marte (2018). Project summary: CO2 seal bypass - a multidisciplinary approach to CO2 migration and storage.
• 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 Vis sammendrag

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

• Sacco, Tatiana; Sundal, Anja & Hellevang, Helge (2018). Mass estimation of CO2 trapping potential in the Smeaheia reservoir.
• Skurtveit, Elin; Sundal, Anja; Soldal, Magnus; Sauvin, Guillaume & Bjørnarå, Tore Ingvald (2018). CO2 Flow, Alteration And Geomechanical Response In Confining Units – An Experimental ApproachGreen Open Access. Fulltekst i vitenarkiv. Vis sammendrag

  Seal integrity during injection operations is a topic of great interest both within the CO2 storage community, for wastewater injection and traditional reservoir pressure support. The Little Grand Wash fault, central Utah, USA, provides an excellent location for studying seal bypass systems in a siliciclastic sedimentary sequence. Two mode I siltstone fractures with significantly different apertures and varying degree of sample bleaching due to alterations from reactive fluid flow are studied together with two intact rock reference samples from the same depth level in the core. The experimental work addresses fracture flow and stiffness relationships. Observed differences in fracture closure trends may be explained as a rapid decrease in stiffness and flow for altered samples due to the fluid rock interaction process altering the fracture surface contact area for this sample

• Sundal, Anja; Hellevang, Helge; Olivarius, Mette; Miri, Rohaldin; Nielsen, Lars-Henrik; Gregersen, Ulrik; Andersen, Odd; Møll-Nilsen, Halvor; Weibel, Rikke & Aagaard, Per (2018). Geological Constraints on the immobilization potential for CO2 in the Gassum Fm. (Skagerrak, Norway).
• Sundal, Anja; Hellevang, Helge & Sacco, Tatiana (2018). CO2 trapping in the Smeaheia reservoir - time mass estimation using geochemical models.
• Sundal, Anja; Weber, Ulrich Wolfgang; Brennwald, Matthias S.; Ringrose, Philip; enaasen flø, nina; Johnsen, Kim; Leila, Faramarzi; Per, Aagaard & Kipfer, Rolf (2018). Monitoring real time, in-line variations of noble gas concentrations during CO2 capture operations by means of a portable mass spectrometer.
• 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.
• Weber, Ulrich Wolfgang; Sundal, Anja; Brennwald, M.S.; Ringrose, Philip; Aagaard, P. & Kipfer, Rolf (2018). CO2 Capture Processes Monitored with Noble Gas Measurements. 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.

• Zuchuat, Valentin; Midtkandal, Ivar; Miquel, Poyatos-More; Da Costa, Sigrid; Halvorsen, Kristine Årland; Sundal, Anja; Cote, Nathan & Braathen, Alvar (2018). Unconformities matter: The spatial and temporal information contained in the J-3 Unconformity and the Curtis Formation, east-central Utah, USA. Vis sammendrag

  Unconformities matter: The spatial and temporal information contained in the J-3 Unconformity and the Curtis Formation, east-central Utah, USA

• Elenius, Maria; Hellevang, Helge; Skurtveit, Elin; Yurushina, Viktoriya; Baig, Irfan; Sundal, Anja; Wangen, Magnus; Landschulze, Karin; Gasda, Sarah Eileen; Kaufmann, Roland; Pettersson, Per & Aavatsmark, Ivar (2017). Storage feasibility in North Sea aquifers.
• Elenius, Maria; Hellevang, Helge; Skurtveit, Elin; Yurushina, Viktoriya; Baig, Irfan; Sundal, Anja; Wangen, Magnus; Landschulze, Karin; Gasda, Sarah Eileen; Kaufmann, Roland; Pettersson, Per & Aavatsmark, Ivar (2017). Workflow for assessment of storage based on sparse data: Skade.
• Elenius, Maria; Hellevang, Helge; Skurtveit, Elin; Yurushina, Viktoriya; Baig, Irfan; Sundal, Anja; Wangen, Magnus; Landschulze, Karin; Gasda, Sarah Eileen; Kaufmann, Roland; Pettersson, Per & Aavatsmark, Ivar (2017). Workflow for evaluation of large-scale CO2 storage feasibility: Skade.
• Andersen, Odd & Sundal, Anja (2017). Slik kan vi lagre CO2 under havbunnen for alltid. Aftenposten Vitenskap.  ISSN 2464-3033. Fulltekst i vitenarkiv. Vis sammendrag

  Berggrunnen under Nordsjøen har et stort potensial som felles lagringssted for CO₂ fra industri i hele Nord-Europa.

• Midtkandal, Ivar; Zuchuat, Valentin; Braathen, Alvar; Sundal, Anja & Evans, James (2017). Syn-sedimentary subsurface liquefaction and collapse; injectites, pseudo-channels and pseudo-clinoforms in the Jurassic Entrada and Curtis Formations, Utah, USA.
• Petrie, Elizabeth; Sundal, Anja; Guiterrez, Marte & Braathen, Alvar (2017). Kinematics of deformation band formation and reactivation associated with a Laramide fault propagation fold.
• Skurtveit, Elin; Sundal, Anja; Sauvin, Guillaume; Soldal, Magnus; Zuchuat, Valentin & Braathen, Alvar (2017). Fracture flow experiments addressing CO2 migration in fault zone.
• Sleveland, Arve Rein Nes; Zuchuat, Valentin; Rimkus, Algirdas; Midtkandal, Ivar; Sundal, Anja & Braathen, Alvar (2017). Spatial and temporal distribution of tidally modified sandstone reservoirs – implications for CCS and petroleum exploration.
• Sundal, Anja (2017). KARBONLAGRING: CO2 + Undergrunn = Sant.
• Sundal, Anja (2017). KARBONLAGRING: Undergrunn + CO2 = trygt. 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.

• Sundal, Anja; Brennwald, Matthias S.; Per, Aagaard; Philip, Ringrose & Rolf, Kipfer (2017). APPLICATION OF NOBLE GAS SIGNATURES IN MONITORING SCHEMES FOR CO2 STORAGE.
• Sundal, Anja; Kipfer, Rolf & Brennwald, Matthias S. (2017). Apparent Heating of Groundwater in the Gardermoen Aquifer, Norway.
• Zuchuat, Valentin; Midtkandal, Ivar; Braathen, Alvar; Sundal, Anja; Skurtveit, Elin; Hellevang, Helge; Tveranger, Jan; Evans, James & Petrie, Elizabeth (2017). COPASS - CO2 seal bypass.
• Zuchuat, Valentin; Midtkandal, Ivar; Da Costa, Sigrid; Sundal, Anja & Braathen, Alvar (2017). Schizophrenia in sedimentology: The J-3 Unconformity and the Curtis Formation, Central-Eastern Utah, USA. Vis sammendrag

  The tide-dominated, Upper Jurassic Curtis Formation crops out in Eastern-Central Utah, overlying the continental to marginal marine Entrada Sandstone. The contact between the two sedimentary formations is formally identified as the J-3 Unconformity, which can be traced over significant distances. It has since been regarded as a “simple” subaerial unconformity, followed by a third order transgression within an enclosed basin and the resulting deposition of the tide-influenced Curtis Formation. However, careful inspection of the different facies and their sub-regional correlation clearly shows that the essence of the J-3 Unconformity is not merely characterised by a long-lasting phase of subaerial exposure. It instead displays evidence of an intricate poly-erosional history, happening during short-lived syn-depositional transgressive and regressive periods. The initial bounding surface was locally altered by processes associated with development of the Curtis Formation, and the nature of their impact is strongly process-dependent. Pre-Curtis erosional processes mainly involved aeolian deflation and fluvial incision, creating a basinwide gentle relief. Syn-Curtis erosional mechanisms were controlled by the distribution and magnitude of tidal forces within the basin, resulting in a steeper and more localised relief in comparison with pre-Curtis widespread denudation. Furthermore, sedimentary processes alone can’t explain the present-day relief observed with the J-3 Unconformity. Indeed, tectonic played, at various scale, a key role in the funnelling of the various erosional forces and the distribution of the depocentres, with (i) m-scale grabens and horsts structures, and (ii) hydroplastic sand remobilisation, both observed within the uppermost strata of the Entrada Sandstone, as well as (iii) syn-Curtis sub-regional tectonic uplift. This study shows that reducing an unconformity to a single process is insufficient. Instead, careful mapping and understanding of such a schizophrenic surface can provide a non-negligible amount of information regarding the dynamic of a basin and its subsequent infill.

• Sundal, Anja; Miri, Rohaldin; Hellevang, Helge; Tveranger, Jan; Midtkandal, Ivar; Zuchuat, Valentin & Braathen, Alvar (2016). Movement of CO2 charged fluids in low permeability rocks during deformation: migration patterns in the Carmel Formation, Utah.
• Guiterrez, Marte; Sundal, Anja & Petrie, Elizabeth (2016). Geomechanical Modeling of Deformation Banding in the Navajo Sandstone, San Rafael Monocline, Utah.
• Sundal, Anja; Midtkandal, Ivar; Benning, Liane; Steele, Andrew; Lutz, Stefanie; Vogel, Marilyn & Swarth, Christopher (2016). Sedimentological setting and biogeochemistry of "sandberries" in the Carboniferous Ebbadalen Formation (Spitsbergen, Norway) – A potential Mars analogue?.
• Sundal, Anja; Petrie, Elizabeth; Hellevang, Helge; Midtkandal, Ivar & Braathen, Alvar (2016). REACTIVE FLUID EXPULSION DURING PROGRESSIVE DEFORMATION IN THE FOLD LIMB OF THE SAN RAFAEL SWELL, UTAH, USA. Vis sammendrag

  A series of reaction fronts radiating from fractures are observed in the Navajo Formation in the eastern flank of the San Rafael Swell (monocline structure) in central Utah, USA. Mobilization of metals by reducing fluids and reprecipitation of oxides may be linked to the structural deformation history and the successive opening and closing of fractures and faults, facilitating pumping of fluids. In the field area the Navajo Formation comprises crossbedded sandstone units interpreted as sand dunes deposited in an aeolian environment during early Jurassic. During the Laramide orogeny the sedimentary succession of Jurassic sandstones and mudstones were uplifted and folded over NS striking underlying faults. Later uplift and erosion has exposed the section and the geology may be investigated in numerous cross cutting gullies. Relict plumes sourced from in between bedding surfaces and from fractures are observed at the field locality as successive reaction fronts where oxides have precipitated and formed solid rims, interpreted as resulting from pressure driven intrusion of reducing fluids. Dendritic growth of Mnoxides is observed from solid precipitation fronts, indicating that diffusiondriven transport succeeds advection and carry large mass fractions. Numerous deformation bands in six directional populations are observed to both obstruct and allow fluid migration between generations of expulsion events. The latest generation of fractures is roughly perpendicular to the regional foldaxis, displaces reaction fronts and deformation bands, and do not appear to expel fluids before becoming completely sealed by oxide precipitates, quartz and carbonate. Thus it appears that the bulk part of advective and diffusive mass transfer took place during the earlier stages of deformation. Understanding these processes is of importance in reservoirseal characterization for CO2 storage, as leakage and reactive transport may be quantified in relation to deformation type and force.

• Algirdas, Rimkus; Sundal, Anja; Sleveland, Arve Rein Nes; Zuchuat, Valentin & Midtkandal, Ivar (2015). Sedimentology and reservoir quality of a tidally modified marginal marine succession; the Middle Jurassic Curtis Formation, southeastern Utah, USA..
• Rimkus, Algirdas; Sundal, Anja; Sleveland, Arve Rein Nes; Zuchuat, Valentin; Braathen, Alvar & Midtkandal, Ivar (2015). Sedimentology and reservoir quality of a Middle Jurassic marginal marine succession; the Curtis Formation, southeastern Utah, USA. Vis sammendrag

  The objective of this study is to investigate the depositional architecture of the Curtis Formation, and evaluate how the observed facies distributions would affect overall reservoir quality. This tidally influenced marginal marine succession is well exposed in southeastern Utah (Humbug Flats, San Rafael Swell) and provides a high-resolution analogue to subsurface reservoirs. In order to constrain the distribution of reservoir-grade sandstone bodies and characterize their heterogeneities, traditional sedimentological field methods were applied and LIDAR-scan data were collected. Permeability, porosity and diagenetic imprint parameters were evaluated from thin sections and used to constrain the model. The Middle Jurassic (Callovian) Curtis and Summerville formations represent a complex set of vertical and lateral facies transitions from tidal shallow marine and supratidal sabkha deposits, respectively. The Curtis Formation developed in a transgressive to regressive, low-gradient epicontinental setting where vertical stacking of sandstone bodies was limited by accommodation. Determining reservoir quality in tidal sediments is extremely challenging due to complex and heterogeneous sand distribution. In this study of the Curtis Formation, sub-seismic scale reservoir heterogeneities are the main focus. Sedimentological characterization is used for classification of significant structures and layers forming potential baffles to fluid flow within genetically related units. Excellent outcrop quality allowed lateral correlation between log sites, supplemented by conventional photographs and LIDAR imagery. The reservoir quality of Curtis Formation shows a general water-depth related trend: sand-to-mud ratio increases with increasing water-depth during the transgressive phase. The lower succession contains channelized sandstone bodies in a heterolithic matrix, leading to limited connectivity. Tidal flat settimg. High permeability A cleaning upwards trend towards the middle part, corresponds with a transition into a deeper shoreface environment, which in turn represents improved reservoir quality with laterally extensive relatively homogeneous sandstones. The uppermost part displays a dirtying-upwards trend into increasingly heterolithic strata. Lateral connectivity is generally high, whereas siltstone interlayers provide frequent vertical flow baffles. Locally, mud-drapes and shifts in depositional transport directions cause high variance in directional permeability. This depositional model for the Curtis Formation is an inter-well-scale analogue with respect to reservoir property distributions in tidally influenced, heterogeneous reservoirs (e.g. the Tilje, Cook and Knurr formations on the Norwegian continental shelf). Evaluation of the diagenetic imprint proved essential, as reservoir behavior at the original burial depth has to be characterized for relevant comparison. Further studies aim to investigate facies distribution within the succession on a regional scale.

• Sundal, Anja (2015). Could enhanced oil or gas recovery enable globally-significant CCS?.
• Sundal, Anja (2015). Geological reservoir selection criteria for long-term CO2 storage.
• Sundal, Anja (2015). Geological storage of CO2 and potential EOR synergies.
• Sundal, Anja; Per, Aagaard; Nystuen, Johan Petter & Dypvik, Henning (2015). Geological reservoir characterization for subsurface CO2 storage: Methodologies for evaluation of reservoir quality and effects of depositional heterogeneities.
• Sundal, Anja; Hellevang, Helge; Miri, Rohaldin & Aagaard, Per (2014). On layer specific CO2 plume distributions and variability in mineralization potential.
• Sundal, Anja; Hellevang, Helge; Miri, Rohaldin; Dypvik, Henning; Nystuen, Johan Petter & Per, Aagaard (2014). Variations in mineralization potential for CO2 related to sedimentary facies and burial Depth - a comparative study from the North Sea. Energy Procedia.  ISSN 1876-6102.
• Sundal, Anja (2014). Trapping mechanisms for CO2 storage, Variations in mineralization potential for CO2 related to sedimentary facies setting and burial depth – a comparative study from the North Sea.

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