Helge Hellevang

• Haile, Beyene Girma; Czarniecka, Urszula; Xi, Kelai; Smyrak-Sikora, Aleksandra; Jahren, Jens; Braathen, Alvar & Hellevang, Helge (2018). Hydrothermally induced diagenesis: Evidence from shallow marine-deltaic sediments, Wilhelmøya, Svalbard. Geoscience Frontiers.  ISSN 1674-9871. . doi: 10.1016/j.gsf.2018.02.015
• Haile, Beyene Girma; Klausen, Tore Grane; Czarniecka, Urszula; Xi, Kelai; Jahren, Jens & Hellevang, Helge (2018). How are diagenesis and reservoir quality linked to depositional facies? A deltaic succession, Edgeøya, Svalbard. Marine and Petroleum Geology.  ISSN 0264-8172.  92, s 519- 546 . doi: 10.1016/j.marpetgeo.2017.11.019
• Haile, Beyene Girma; Klausen, Tore Grane; Jahren, Jens; Braathen, Alvar & Hellevang, Helge (2018). Thermal history of a Triassic sedimentary sequence verified by a multi-method approach: Edgeøya, Svalbard, Norway. Basin Research.  ISSN 0950-091X. . doi: 10.1111/bre.12292
• Nooraiepour, Mohammad; Fazeli, Hossein; Miri, Rohaldin & Hellevang, Helge (2018). Effect of CO2 Phase States and Flow Rate on Salt Precipitation in Shale Caprocks—A Microfluidic Study. Environmental Science and Technology.  ISSN 0013-936X. . doi: 10.1021/acs.est.8b00251 Vis sammendrag

  Fracture networks inside the caprock for CO2 storage reservoirs may serve as leakage pathways. Fluid flow through fractured caprocks and bypass conduits, however, can be restrained or diminished by mineral precipitations. This study investigates precipitation of salt crystals in an artificial fracture network as a function of pressure–temperature conditions and CO2 phase states. The impact of CO2 flow rate on salt precipitation was also studied. The primary research objective was to examine whether salt precipitation can block potential CO2 leakage pathways. In this study, we developed a novel microfluidic high-pressure high-temperature vessel to house geomaterial micromodels. A fracture network was laser-scribed on the organic-rich shales of the Draupne Formation, the primary caprock for the Smeaheia CO2 storage in Norway. Experimental observations demonstrated that CO2 phase states influence the magnitude, distribution, and precipitation patterns of salt accumulations. The CO2 phase states also affect the relationship between injection rate and extent of precipitated salts due to differences in solubility of water in CO2 and density of different CO2 phases. Injection of gaseous CO2 resulted in higher salt precipitation compared to liquid and supercritical CO2. It is shown that micrometer-sized halite crystals have the potential to partially or entirely clog fracture apertures.

• Hellevang, Helge; Haile, Beyene Girma & Abednego, Tetteh (2017). Experimental study to better understand factors affecting the CO2 mineral trapping potential of basalt. Greenhouse Gases: Science and Technology.  ISSN 2152-3878.  7(1), s 143- 157 . doi: 10.1002/ghg.1619
• Nooraiepour, Mohammad; Haile, Beyene Girma & Hellevang, Helge (2017). Compaction and mechanical strength of Middle Miocene mudstones in the Norwegian North Sea - the major seal for the Skade CO2 storage reservoir. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  67, s 49- 59 . doi: 10.1016/j.ijggc.2017.10.016 Vis sammendrag

  This study has investigated petrophysical, acoustic and geomechanical properties of Middle Miocene mudstones in the Norwegian North Sea as the primary caprock for Skade CO2 storage reservoir. To evaluate the seal properties, we analyzed collected drill cuttings and measured well logs from well 16/4-1, in addition to an extensive well log database in the Northern North Sea. The studied caprock was identified as siliceous ooze-rich mudstones with low bulk density, high shear wave velocity, and low Vp/Vs ratio. The abundance of siliceous skeletal material resulted in a significant shift from the overall trend of mudstones within the Hordaland Group. The estimated scenarios for S-wave velocity depicted that the ooze-rich mudstones have the highest brittleness of the Hordaland Group semi-consolidated rocks. The brittleness indices in well 16/4-1 illustrated that the mineralogical composition-based indices significantly overestimate brittleness compared to the elastic-based indices. While the caprock for Skade CO2 storage reservoir showed an overall ductility, the bottom 30 m demonstrated an increased brittleness profile. The more brittle ooze-rich mudstones also indicated the lowest estimation of fracture pressure compared to other scenarios. The research outcomes emphasize on the influence of mudstone type and microstructure on the macroscale physical properties of shallow semi-compacted CO2 caprocks.

• Nooraiepour, Mohammad; Mondol, Nazmul Haque; Hellevang, Helge & Bjørlykke, Knut (2017). Experimental mechanical compaction of reconstituted shale and mudstone aggregates: Investigation of petrophysical and acoustic properties of SW Barents Sea cap rock sequences. Marine and Petroleum Geology.  ISSN 0264-8172.  80, s 265- 292 . doi: 10.1016/j.marpetgeo.2016.12.003 Vis sammendrag

  This study investigates petrophysical and acoustic properties of experimentally compacted reconstituted samples of seal sequences from the southwestern Barents Sea. The aggregates were collected from drill cuttings of mudstone and shale formations of two exploration wells, 7220/10-1 (Salina discovery) and 7122/7-3 (Goliat field). The washed and freeze-dried samples were characterized for grain size distributions, geochemical analyses, and mineralogical compositions. A total of 25 compaction tests (12 dry and 13 brine-saturated) were performed with a maximum effective vertical stress of 50 MPa. The laboratory measurements demonstrated that petrophysical and acoustic properties of argillaceous sediments can change within a sedimentary basin and even within a given formation. The results show that the collected aggregates from Goliat field are compacted more compared to Salina discovery. The maximum and minimum compaction are measured in samples collected from Snadd and Fuglen formations, respectively. The final porosity of brine-saturated specimens varies between 5% and 22%. The ultrasonic velocity measurements depict that samples with the same porosity values can have a broad range of velocity values. The resulting compaction trends in this study were compared to published compaction curves for synthetic mixtures of quartz and clay. All compaction trends show higher porosity reduction than the silt fraction with 100% quartz. Comparison of experimental compaction result of each mudstone and shale aggregate with its corresponding acquired well log data helps to delineate the burial history and exhumation in the study area. A net exhumation of 950 m and 800 m is estimated at Salina and Goliat wells, respectively. The outcomes of this study can provide insights for hydrocarbon prospect discovery in a pre-mature sedimentary basin in terms of exploration and production, and also for geological CO2 storage sites. The experimental results may provide information for well log and seismic interpretation, basin modeling and seal integrity of investigated horizons.

• 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
• Ahmad, Nawaz; Anders, Wörman; Xavier, Sanchez-Vila; Jerker, Jarsjö; Andrea, Bottacin-Busolin & Hellevang, Helge (2016). Injection of CO2-saturated brine in geological reservoir: A way to enhanced storage safety. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  54(1), s 129- 144 . doi: 10.1016/j.ijggc.2016.08.028
• Hellevang, Helge; Haile, Beyene Girma & Miri, Rohaldin (2016). A Statistical Approach to Explain the Solution Stoichiometry Effect on Crystal Growth Rates. Crystal Growth & Design.  ISSN 1528-7483.  16(3), s 1337- 1348 . doi: 10.1021/acs.cgd.5b01466
• Kirstein, Jens; Hellevang, Helge; Haile, Beyene Girma; Gleixner, Gerd & Gaupp, Reinhard (2016). Experimental determination of natural carbonate rock dissolution rates with a focus on temperature dependency. Geomorphology.  ISSN 0169-555X.  261, s 30- 40 . doi: 10.1016/j.geomorph.2016.02.019
• Miri, Rohaldin & Hellevang, Helge (2016). Salt precipitation during CO2 storage - a review. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  51, s 136- 147 . doi: 10.1016/j.ijggc.2016.05.015
• Naseryan Moghadam, Javad; Mondol, Nazmul Haque; Aagaard, Per & Hellevang, Helge (2016). Effective stress law for the permeability of clay-bearing sandstones by the Modified Clay Shell model. Greenhouse Gases: Science and Technology.  ISSN 2152-3878.  6(6), s 752- 774 . doi: 10.1002/ghg.1612 Vis sammendrag

  In this study, the effective stress law for the permeability of two core plugs selected from Berea (Cleveland Quarries, OH, USA) and Knorringfjellet (Longyearbyen, Svalbard, Norway) sandstones is studied experimentally by measuring the core permeability (k) under varying confining stress (σc) and pore pressures (Pp). The obtained results demonstrate that the permeabilities of the two core plugs decrease with increasing σc or decreasing Pp. The effective stress coefficient for the permeability (αk) values are more than 1.0 for both sandstone core plugs indicating higher sensitivity of the permeability with respect to the applied Pp compared to the applied σc. The previously presented models for calculating αk, such as the Clay Free, Clay Shell, and Clay Particle models, are discussed and a new modified Clay Shell model considering spherical geometry is presented to account for the considerable contrast between the elastic moduli of quartz and clay minerals. The discussed models strongly depend on the magnitude of the considered elastic moduli for the clay minerals. While the Clay Shell and Clay Particle models are capable of describing the observed αk values by considering extremely low elastic moduli for clays, the new modified Clay Shell model is capable of predicting αk values by considering moderate to low values of elastic moduli of clays. The increasing trend of αk values by increasing the σc is discussed and a new correlation based on the observed k values for calculation of αk is presented.

• Naseryan Moghadam, Javad; Mondol, Nazmul Haque; Aagaard, Per & Hellevang, Helge (2016). Experimental investigation of seismic velocity behavior of CO2 saturated sandstones under varying temperature and pressure conditions. Greenhouse Gases: Science and Technology.  ISSN 2152-3878.  6(6), s 734- 751 . doi: 10.1002/ghg.1603 Vis sammendrag

  Subsurface storage of CO2 into geological formations is considered an important strategy to mitigate increasing atmospheric CO2. Time-lapse seismic monitoring is an integral component of a geological CO2 sequestration project because the seismic behavior of the rock is a function of both mineralogical composition and pore fluid properties. At the uppermost kilometer of the sedimentary basin, CO2 can be present at gaseous, liquid, and supercritical states, with the supercritical and liquid states preferred in CO2 storage operations due to the higher sweep efficiency. In this study, the seismic velocities [both compressional (Vp) and shear (Vs) waves] of two CO2-saturated sandstone core plugs (Red Wildmoor and Knorringfjellet formations) have been measured under a range of temperatures and pressures in which CO2 phase transitions occur. The experiments were done using a uniaxial hydrostatic cell equipped with seismic wave transmitting and receiving transducers. The experimental investigation illustrated that seismic velocities (both Vp and Vs) decreased until the critical point was reached. Further increases in the CO2 pressure above the critical point led to a gradual increasing of Vp while the Vs remained unchanged. The effect of CO2 on the seismic velocity of the sandstone was compared with the effects of N2 and distilled water at the same conditions. It was further indicated that the seismic velocity changes were mainly connected to significant changes of CO2 density and the corresponding bulk rock moduli over the critical point. The observed velocities are in good agreement with Gassmann-predicted velocities as well as literature data.

• Szabo, Zsuzanna; Hellevang, Helge; Kiraly, Csilla; Sendula, Eszter; Kónya, Péter; Falus, György; Török, Szabina B. & Szabó, Csaba (2016). Experimental-modelling geochemical study of potential CCS caprocks in brine and CO2-saturated brine. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  44, s 262- 275 . doi: 10.1016/j.ijggc.2015.11.027
• Xi, Kelai; Cao, Yingchang; Haile, Beyene Girma; Zhu, Rukai; Jahren, Jens; Bjørlykke, Knut; Zhang, Xiangxiang & Hellevang, Helge (2016). How does the pore-throat size control the reservoir quality and oiliness of tight sandstones? The case of the Lower Cretaceous Quantou Formation in the southern Songliao Basin, China. Marine and Petroleum Geology.  ISSN 0264-8172.  76, s 1- 15 . doi: 10.1016/j.marpetgeo.2016.05.001
• Xi, Kelai; Cao, Yingchang; Zhu, Rukai; Haile, Beyene Girma & Hellevang, Helge (2016). Evidences of localized CO2-induced diagenesis in the Cretaceous Quantou Formation, southern Songliao Basin, China. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  52, s 155- 174 . doi: 10.1016/j.ijggc.2016.07.010
• Haile, Beyene Girma; Hellevang, Helge; Aagaard, Per & Jahren, Jens (2015). Experimental nucleation and growth of smectite and chlorite coatings on clean feldspar and quartz grain surfaces. Marine and Petroleum Geology.  ISSN 0264-8172.  68(Part A), s 664- 674 . doi: 10.1016/j.marpetgeo.2015.02.006
• Hellevang, Helge & Aagaard, Per (2015). Constraints on natural global atmospheric CO2 fluxes from 1860 to 2010 using a simplified explicit forward model. Scientific Reports.  ISSN 2045-2322.  5 . doi: 10.1038/srep17352 Fulltekst i vitenarkiv.
• Miri, Rohaldin; Van Noort, Reinier; Aagaard, Per & Hellevang, Helge (2015). New insights on the physics of salt precipitation during injection of CO2 into saline aquifers. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  43, s 10- 21 . doi: 10.1016/j.ijggc.2015.10.004
• Tambach, TJ & Hellevang, Helge (2015). Discussion on the paper titled "Effect of reactive surface area of minerals on mineralization and carbon dioxide trapping in a depleted gas reservoir" by Bolourinejad et al. (2014). International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  34, s 141- 143 . doi: 10.1016/j.ijggc.2014.12.018
• Xi, Kelai; Cao, Y; Jahren, Jens; Zhu, R; Bjørlykke, Knut; Haile, Beyene Girma; Zheng, L & Hellevang, Helge (2015). Diagenesis and reservoir quality of the Lower Cretaceous Quantou Formation tight sandstones in the southern Songliao Basin, China. Sedimentary Geology.  ISSN 0037-0738.  330, s 90- 107 . doi: 10.1016/j.sedgeo.2015.10.007
• Xi, Kelai; Cao, Y; Jahren, Jens; Zhu, R; Bjørlykke, Knut; Zhang, X; Cai, L & Hellevang, Helge (2015). Quartz cement and its origin in tight sandstone reservoirs of the Cretaceous Quantou formation in the southern Songliao basin, China. Marine and Petroleum Geology.  ISSN 0264-8172.  66(4), s 748- 763 . doi: 10.1016/j.marpetgeo.2015.07.017
• Hellevang, Helge; Aagaard, Per & Jahren, Jens (2014). Will dawsonite form during CO2 storage?. Greenhouse Gases: Science and Technology.  ISSN 2152-3878.  4(2), s 191- 199 . doi: 10.1002/ghg.1378
• Hellevang, Helge; Miri, Rohaldin & Haile, Beyene Girma (2014). New insights into the mechanisms controlling the rate of crystal growth. Crystal Growth & Design.  ISSN 1528-7483.  14(12), s 6451- 6458 . doi: 10.1021/cg501294w
• Miri, Rohaldin; Aagaard, Per & Hellevang, Helge (2014). Examination of CO2–SO2 Solubility in Water by SAFT1. Implications for CO2 Transport and Storage. Journal of Physical Chemistry B.  ISSN 1520-6106.  118(34), s 10214- 10223 . doi: 10.1021/jp505562j
• Miri, Rohaldin; Hellevang, Helge; Braathen, Alvar & Aagaard, Per (2014). Phase relations in the Longyearbyen CO2 Lab reservoir - forecasts for CO2 injection and migration. Norsk Geologisk Tidsskrift.  ISSN 0029-196X.  94(2-3), s 217- 232
• Naseryan-Moghadam, Javad; Mondol, Nazmul Haque; Hellevang, Helge; Johnsen, Øistein & Aagaard, Per (2014). Seismic Response of CO2 Saturated Red Wildmoor Sandstone under Varying Temperatures and Pressures, In EAGE2014 (ed.),  Workshop Proceedings. 76th EAGE Conference & Exhibition.  European Association of Geoscientists and Engineers.  ISBN 978-90-73834-90-3.  Tu G107 15.
• Neubeck, Anna; Duc, Nguyen Thanh; Hellevang, Helge; Oze, Christopher; Bastviken, David; Bacsik, Zoltan & Holm, Nils G. (2014). Olivine alteration and H2 production in carbonate-rich, low temperature aqueous environments. Planetary and Space Science.  ISSN 0032-0633.  96, s 51- 61 . doi: 10.1016/j.pss.2014.02.014
• Hellevang, Helge & Aagaard, Per (2013). Can the long-term potential for carbonatization and safe long-term CO2 storage in sedimentary formations be predicted?. Applied Geochemistry.  ISSN 0883-2927.  39, s 108- 118 . doi: 10.1016/j.apgeochem.2013.09.012
• Hellevang, Helge; Dypvik, Henning; Kalleson, Elin; Pittarello, Lidia & Koeberl, Christian (2013). Can alteration experiments of impact melts from El'gygytgyn and volcanic glasses shed new light on the formation of the Martian surface?. Meteoritics and Planetary Science.  ISSN 1086-9379.  48(7), s 1287- 1295 . doi: 10.1111/maps.12046
• Hellevang, Helge; Pham, Van Thi Hai & Aagaard, Per (2013). Kinetic modelling of CO2-water-rock interactions. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  15, s 3- 15 . doi: 10.1016/j.ijggc.2013.01.027
• Liu, Faye; Lu, Peng; Griffith, Craig; Hedges, Sheila W.; Soong, Yee; Hellevang, Helge & Zhu, Chen (2012). CO2-brine-caprock interaction: Reactivity experiments on Eau Claire shale and a review of relevant literature. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  7, s 153- 167 . doi: 10.1016/j.ijggc.2012.01.012
• Pham, Van Thi Hai; Aagaard, Per & Hellevang, Helge (2012). On the potential for CO2 mineral storage in continental flood basalts - PHREEQC batch- and 1D diffusion-reaction simulations. Geochemical Transactions.  ISSN 1467-4866.  13 . doi: 10.1186/1467-4866-13-5
• Aker, Eyvind; Bjørnarå, Tore Ingvald; Braathen, Alvar; Brandvoll, Øyvind; Dahle, Helge K.; Nordbotten, Jan Martin; Aagaard, Per; Hellevang, Helge; Alemu, Binyam Lema; Pham, Van Thi Hai; Johansen, Harald; Wangen, Magnus; Nøttvedt, Arvid; Aavatsmark, Ivar; Johannessen, Truls & Durand, Dominique (2011). SUCCESS: SUbsurface CO2 storage–Critical elements and superior strategy. Energy Procedia.  ISSN 1876-6102.  4, s 6117- 6124 . doi: 10.1016/j.egypro.2011.02.619 Fulltekst i vitenarkiv. Vis sammendrag

  SUCCESS is a Center for Environmental Energy Research in Norway and performs research related to geological storage of CO2 in the subsurface. The SUCCESS centre is established by the Research Council of Norway together with several Norwegian research institutes and universities. The centre is hosted by Christian Michelsen Research. Through international cooperation and open research the SUCCESS centre will fill gaps in strategic knowledge and provide a system for learning and development of new competency to ensure safe and effective CO2 injection, storage and monitoring. In this paper we briefly present the main focus areas of the centre and some recent results obtained by the research partners. The results relate to geochemical effects, reservoir modeling, monitoring the geomechanical respond and the marine environment. A brief status on the field trial, Longyearbyen CO2 Lab, at Svalbard is also provided.

• Hellevang, Helge; Declercq, Julien & Aagaard, Per (2011). Why is Dawsonite Absent in CO2 Charged Reservoirs?. Oil & gas science and technology.  ISSN 1294-4475.  66(1), s 119- 135 . doi: 10.2516/ogst/2011002
• Hellevang, Helge; Huang, Shanshan & Thorseth, Ingunn Hindenes (2011). The potential for low-temperature abiotic hydrogen generation and a hydrogen-driven deep biosphere. Astrobiology.  ISSN 1531-1074.  11(7), s 711- 724 . doi: 10.1089/ast.2010.0559
• Khattri, Sanjay Kumar; Fladmark, Gunnar E; Hellevang, Helge & Kvamme, Bjørn (2011). Simulation of long-term fate of CO2 in the sand of Utsira. Journal of Porous Media.  ISSN 1091-028X.  14(2), s 149- 166 Vis sammendrag

  Carbon dioxide (CO2) released during fossil fuel consumption is a major source of greenhouse gases. Geological storage of CO2 is a strategy to reduce emissions of CO2 into the atmosphere. For the success of safe deposition of CO2 into geological formations, it is required to understand the detailed behaviour of CO2 dynamics. For this purpose, we have developed a reactive fluid flow and geochemical transport numerical model for predicting long-term disposal of green house gases in geological formations. The model is based on a compositional reservoir simulator in which mineral and chemical reactions are integrated. The model consists of fifteen chemical species and sixteen mineral species. In this work, we present mathematical models and their discretization for capturing major physical processes associated with CO2 sequestration/deposition in a porous medium. We verify our simulator by comparing our results against available results. We also simulated two scenarios with and without regional flow. We analyze impact of fluid movement on long term CO2 migration at the Utsira formation. Here, we analyze how flow of medium fluids affects important parameters such as the pH and CO2 saturation. The input data for the simulations has similarity with the CO2 storage facility at the Sleipner Vest field in the Norwegian sector of the North Sea, for example, injection rate, injection period, properties of sand and shale layers

• Pham, Van Thi Hai; Lu, P; Aagaard, Per; Zhu, Chen & Hellevang, Helge (2011). On the potential of CO2-water-rock interactions for CO2 storage using a modified kinetic model. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  5(4), s 1002- 1015 . doi: 10.1016/j.ijggc.2010.12.002
• Pham, Van Thi Hai; Maast, Tom Erik; Hellevang, Helge & Aagaard, Per (2011). Numerical modeling including hysteresis properties for CO2 storage in Tubåen formation, Snøhvit field, Barents Sea. Energy Procedia.  ISSN 1876-6102.  4, s 3746- 3753 . doi: 10.1016/j.egypro.2011.02.308
• Hellevang, Helge; Declercq, Julien; Kvamme, Bjørn & Aagaard, Per (2010). The dissolution rates of dawsonite at pH 0.9 to 5 and temperatures of 22, 60 and 77 degrees C. Applied Geochemistry.  ISSN 0883-2927.  25(10), s 1575- 1586 . doi: 10.1016/j.apgeochem.2010.08.007

Se alle arbeider i Cristin

• Haile, Beyene Girma; Hellevang, Helge & Jahren, Jens (2018). Reservoir quality of the Upper Triassic to Lower Jurassic sediments, NW Barents Shelf. Understanding porosity evolution through diagenesis and sedimentology. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 1973.
• Bjørlykke, Knut; Jahren, Jens; Mondol, Nazmul Haque; Hellevang, Helge & Aagaard, Per (2017). Mechanical compaction of sand and clay: Constraints from experimental compaction, chemical reactions and fluid flow during burial-An overview.
• 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.
• Haile, Beyene Girma; Jahren, Jens & Hellevang, Helge (2017). New insights about thermally driven diagenetic changes due to the emplacement of magmatic sills into reservoir sediments at Wilhelmøya (Svalbard): Implications for reservoir quality.
• Haile, Beyene Girma; Klausen, Tore Grane; Czarniecka, Urszula; Xi, Kelai; Jahren, Jens; Braathen, Alvar & Hellevang, Helge (2017). Diagenesis of Upper Triassic sandstones, Edgeøya, Svalbard.
• Line, Lina Hedvig; Jahren, Jens & Hellevang, Helge (2017). Diagenesis and Reservoir Quality of Anisian and Carnian channels in the southwestern Barents Sea.
• Line, Lina Hedvig; Jahren, Jens & Hellevang, Helge (2017). Diagenesis and Reservoir quality of Anisian and Carnian channels in the southwestern Barents Sea.
• Line, Lina Hedvig; Jahren, Jens & Hellevang, Helge (2017). Reservoir characterization of Triassic sandstones in the southwestern Barents Sea.
• Moghadam, Javad Naseryan; Mondol, Nazmul Haque; Aagaard, Per & Hellevang, Helge (2017). Determination of CO2-Brine relative permeability curves for CO2 storage sandstone reservoirs.
• Nooraiepour, Mohammad; Fazeli, Hossein & Hellevang, Helge (2017). Effect of CO2 phase state and flow rate on salt formation in shale caprocks – a microfluidics study.
• Zuchuat, Valentin; Midtkandal, Ivar; Braathen, Alvar; Sundal, Anja; Skurtveit, Elin; Hellevang, Helge; Tveranger, Jan; Evans, James & Petrie, Elizabeth (2017). COPASS - CO2 seal bypass.
• Haile, Beyene Girma; Klausen, Tore Grane; Hellevang, Helge; Jahren, Jens & Bjørlykke, Knut (2016). Burial diagenesis of De Geerdalen Formation control by depositional facies distribution, Edgeøya, Svalbard.
• 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.
• 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.

• Sætre, Christian; Dypvik, Henning & Hellevang, Helge (2016). Basaltic glass alteration and its reservoir importance.
• Sætre, Christian; Dypvik, Henning; Hellevang, Helge & Werner, Stephanie C. (2016). Earth Mars Analogues - Linking experimental and Martian clays.
• Braathen, Alvar; Anell, Ingrid Margareta; Smyrak-Sikora, Aleksandra Anna; Mulrooney, Mark; Haile, Beyene Girma; Ogata, Kei; Osmundsen, Per Terje; Maher, Harmon; Buckley, Simon John; Hellevang, Helge & Olaussen, Snorre (2015). Tectonic influence on platform infill patterns in the mid-late Triassic, Southern Edgeøya, Svalbard.
• Haile, Beyene Girma; Xi, Kelai; Jahren, Jens; Aagaard, Per; Bjørlykke, Knut & Hellevang, Helge (2015). Burial Diagenesis in Triassic Sandstones: key to understand reservior quality evolution.
• Haile, Beyene Girma; Xi, Kelai; Jahren, Jens; Aagaard, Per; Bjørlykke, Knut & Hellevang, Helge (2015). Burial diagenesis in Triassic siliciclastic reservoirs of the Barents Sea region.
• Hellevang, Helge (2015). Carbon capture and storage (CCS), In Knut Bjørlykke (ed.),  Petroleum Geoscience. From sedimentary environments to rock physics - second edition.  Encyclopedia of Global Archaeology/Springer Verlag.  ISBN 978-3-642-34131-1.  Kapittel 24.  s 591 - 602
• Hellevang, Helge (2015, 18. juni). Hva bestemmer isotopsignaturen til karbon i atmosfæren?. [Internett].  geoforskning.no.
• Hellevang, Helge & Aagaard, Per (2015, 21. april). Kort oppholdstid for karbon i atmosfæren – bevis mot menneskeskapte utslipp?. [Internett].  geoforskning.no.
• Hellevang, Helge; Krafft, Charlotte Gannefors & Dalsbø, Gudmund Anders (2015). FME SUCCESS WP1 – Reservoir.
• Midtkandal, Ivar; Braathen, Alvar; Hellevang, Helge; Skurtveit, Elin & Tveranger, Jan (2015). COPASS - CO2 seal bypass.
• Miri, Rohaldin; Hellevang, Helge; Aagaard, Per & Wangen, Magnus (2015). Effects of CO2-Brine-Rock Interactions on CO2 Injectivity - Implications for CCS.
• Miri, Rohaldin & Hellevang, Helge (2014). Developments in SAFT EOS for Carbon Capture and Storage (CSS).
• Moghadam, Javad Naseryan; Mondol, Nazmul Haque; Hellevang, Helge; Johnsen, Øistein & Aagaard, Per (2014). Seismic response of CO2 saturated Red Wildmoor Sandstone under varying temperatures and pressures. EarthDoc.  (Tu G107)
• 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.
• Hellevang, Helge; Jahren, Jens; Haile, Beyene Girma & Aagaard, Per (2013). On the kinetics of digenetic reactions – Diffusion /transport limitations on the K-feldspar to illite conversion during burial diagenesis.
• Jahren, Jens; Haile, Beyene Girma; Hellevang, Helge; Bjørlykke, Knut & Ohm, Sverre Ekrene (2013). Fracture Patterns in Organic Rich Mudstones - Implications for Primary Petroleum Migration. EarthDoc. . doi: 10.3997/2214-4609.20130098
• Jahren, Jens; Haile, Beyene Girma; Hellevang, Helge & Kjemperud, Audun (2013). Formation of potentially porosity preserving grain coats in Brent and Dunlin age sandstones from the Northeastern North Sea area-A combined petrographic and hydrothermal synthesis study of samples from the Gjøa and Agat areas.
• Naseryan-Moghadam, Javad; Aagaard, Per; Mondol, Nazmul Haque & Hellevang, Helge (2013). Determination of the Biot’s coefficient for the permeability of DeGeerdalen and Knorringfjellet sandstones, two consolidated formations for CO2 sequestration in Svalbard area.
• Dypvik, Henning; Hellevang, Helge & Kalleson, Elin (2012). Alteration of impact melts.
• Dypvik, Henning; Hellevang, Helge & Kalleson, Elin (2012). Alteration of impact melt - implications for our understanding of Noachian of Mars?.
• Hellevang, Helge (2012). Pressures and their mechanisms governing loading of P fractions.
• Dypvik, Henning; Hellevang, Helge & Kalleson, Elin (2011). From impact melt to clays; experiments and speculations.
• Dypvik, Henning; Hellevang, Helge & Kalleson, Elin (2011). The alteration of impact melt - a first step.
• Aagaard, Per; Hellevang, Helge; Alemu, Binyam Lema & Pham, Van Thi Hai (2011). On the potential for secondary carbonate growth in sedimentary basins.
• Alemu, Binyam Lema; Aagaard, Per & Hellevang, Helge (2011). Effect of temperature and mineralogical composition on the reactivity of shale: A comparison study of potential caprock from two potential CO2 storage sites.
• Bjørlykke, Knut; Hellevang, Helge & Aagaard, Per (2011). Konsekvensene av surere hav.Noen geokjemiske betraktninger av betydning for livet i havet. Biologen.  2, s 28- 34
• Hellevang, Helge; Alemu, Binyam Lema & Aagaard, Per (2011). Mobilization of elements by CO2-mineral interactions.
• Hellevang, Helge; Thyberg, Brit Inger & Jahren, Jens (2011). Albite precipitation in mudstones – comparison of natural and synthetic systems.
• Huang, Shanshan; Hellevang, Helge & Thorseth, Ingunn Hindenes (2011). Hydrogen production from low temperature olivine alteration.
• Pham, Van Thi Hai; Hellevang, Helge & Aagaard, Per (2011). On the potential for CO2 mineral storage in continental flood basalts.
• Hellevang, Helge; Jahren, Jens; Aagaard, Per & Thyberg, Brit Inger (2010). On spatial-temporal variations of secondary phases formed during mud diagenesis.
• Sokalska, Ewa Teresa; Hellevang, Helge & Aagaard, Per (2010). CHLORITE INTERACTION WITH ACID FLUID.
• Sokalska, Ewa Teresa; Hellevang, Helge & Aagaard, Per (2010). ROZKŁAD CHLORYTU W KWAŚNYCH ROZTWORACH.
• Sokalska, Ewa Teresa; Hellevang, Helge; Alemu, Binyam Lema; Aagaard, Per; Dubińska, Elżbieta & Kaproń, Grzegorz (2010). Chlorite dissolution and carbonate precipitation under hydrothermal conditions.
• Sokalska, Ewa Teresa; Hellevang, Helge; Alemu, Binyam Lema; Aagaard, Per; Dubińska, Elżbieta & Kaproń, Grzegorz (2010). Chlorite dissolution and carbonate precipitation under hydrothermal conditions. NGF Abstracts and Proceedings of the Geological Society of Norway.  1, s 184- 184
• Hellevang, Helge & Aagaard, Per (2010). Can carbonate precipitation rates be derived from dissolution rate data?. Geochimica et Cosmochimica Acta.  ISSN 0016-7037.  74(12), s A396- A396
• Hellevang, Helge & Aagaard, Per (2010). On the use of Transition-State-Theory (TST) to predict the potential for carbonate growth in sedimentary basins.
• Hellevang, Helge; Declercq, Julien & Aagaard, Per (2010). Carbonation of forsterite at 10 to 18.5 bar PCO2and 85 to 150C –Comparisons of numerical simulations and laboratory experiments.
• Hellevang, Helge; Pham, Van Thi Hai & Aagaard, Per (2010). Can carbonate precipitation rates be derived from dissolution rate data?.
• Pham, Van Thi Hai; Hellevang, Helge & Aagaard, Per (2010). On the potential of carbonate formation during CO2 storage. The Utsira case revised.
• Aagaard, Per; Austrheim, Håkon Olav & Hellevang, Helge (2009). CO2 sequestration in serpentinized peridotite - thermodynamic modelling of a natural occurence.
• Aagaard, Per; Hellevang, Helge & Jahren, Jens (2009). Burial diagenesis of siliciclastic reservoirs and control on formation water chemistry. Geochimica et Cosmochimica Acta.  ISSN 0016-7037.  73(13), s A1- A1

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