| 1. |
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| 2. |
- Bensabat, Jacob, et al.
(författare)
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Model for the dependence of conditions at the injection well head and the reservoir during CO2 injection
- 2011
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Konferensbidrag (refereegranskat)abstract
- Highly controlled field injection experiments are necessary for demonstration, for scientific understanding and for quantification of the relevant processes of CO2 geological storage.The preparation of such an experiment requires reliable information on both the hydraulic, thermal and chemical properties of the target layer and the formation fluid as well as on the injection discharges and their associated pressure build-up in the reservoir. For this, there is a need to determine the state variables of CO2 in the injection tube near the well head, which can produce the desired mass flow rates given the condition at the reservoir, while respecting pressure buildup constraints. A model connecting the multiphase flow and transport processes in the target layer (based on the well-known TOUGH2/ECO2N model) at the vicinity of the injection well with those occurring in the injection tube (solving the one dimensional equations mass, momentum and energy conservation) has been developed. To this model the injection tube is a boundary condition. Once the reservoir pressure build-up resulting from the injection discharge is known, there is a need to determine the necessary injection conditions at the wellhead. For this purpose we apply the 1-D tube model, which provides the solution of the conditions in the injection pipe, given the injection rate and the pressure at the reservoir. These two linked models, the porous medium model and the pipe model, are applied to the planning of the Heletz injection experiment to be carried out in the frame of the EU-FP7 funded MUSTANG project. Sensitivity analyses are carried out with regard to uncertainty in the target layer permeability and the temperature of the injected CO2, which depends on the thermal heat transfer coefficient in the injection tube.
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| 3. |
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| 4. |
- Kitron-Belinkov, Myra, et al.
(författare)
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Modeling wellbore and reservoir carbon dioxide flow for the Heletz experiment
- 2012
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Ingår i: Geophysical Research Abstracts, Vol. 14.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Field carbon dioxide injection experiments are necessary for demonstration, increasing the scientific understandingand quantification of the relevant processes occurring during geological storage in deep saline aquifers. As part ofthe large scale EU-FP7 project MUSTANG, a carbon dioxide injection experiment is to be carried out at the Heletzsite, Israel. Estimating the well head conditions is an important part of planning the experiment and an approach ispresented here for determining wellhead conditions needed to ensure that at least a specified flow rate is providedto the formation, given target layer conditions, while still respecting pressure buildup constraints. The main partof the study combines the multiphase flow in the target layer using the well known TOUGH2/ECO2N model, withthe flow in the injection pipe solving the 1D steady, real gas, augmented Euler equation. The Matching is carriedon in a two-stage process.The second part consists of a transient simulation of the combined well-reservoir flowusing the new T2WELL software for the same parameters. Preliminary conclusions of the comparison of the twostrategies are derived. Sensitivity analyses were carried out with respect to target layer properties and to pipe modelassumptions.
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| 5. |
- Niemi, Auli, et al.
(författare)
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Small-Scale CO2 Injection into a Deep Geological Formation at Heletz, Israel
- 2012
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 23, s. 504-511
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the experimental plans and designs as well as examples of predictive modeling of a pilot-scale CO2 injection experiment at the Heletz site (Israel). The overall objective of the experiment is to find optimal ways to characterize CO2 -relevant in-situ medium properties, including field-scale residual and dissolution trapping, to explore ways of characterizing heterogeneity through joint analysis of different types of data, and to detect leakage. The experiment will involve two wells, an injection well and a monitoring well. Prior to the actual CO2 injection, hydraulic, thermal and tracer tests will be carried out for standard site characterization. The actual CO2 injection experiments will include (i) a single well injection-withdrawal experiment, with the main objective to estimate in-situ residual trapping and (ii) a two-well injection-withdrawal test with injection of CO2 in a dipole mode (injection of CO2 in one well with simultaneous withdrawal of water in the monitoring well), with the objective to understand the CO2 transport in heterogeneous geology as well as the associated dissolution and residual trapping. Tracers will be introduced in both experiments to further aid in detecting the development of the phase composition during CO2 transport. Geophysical monitoring will also be implemented. By means of modeling, different experimental sequences and injection/withdrawal patterns have been analyzed, as have parameter uncertainties. The objectives have been to (i) evaluate key aspects of the experimental design, (ii) to identify key parameters affecting the fate of the CO2 and (iii) to evaluate the relationships between measurable quantities and parameters of interest.
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| 6. |
- Oskarsson, Magnus, 1962-, et al.
(författare)
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PISA 2015 - Bakgrund och metoder med exempel
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- År 2015 genomfördes för sjätte gången OECD:s internationella kunskaps-undersökning PISA (Programme for International Student Assessment). Studien har sedan 2000 genomförts vart tredje år och undersöker 15-åriga elevers kunskaper i naturvetenskap, läsförståelse och matematik. PISA syftar också till att öka förståelsen för orsakerna till och konsekvenserna av observerade skillnader i kunskaper.Vid varje mätning turas de tre kunskapsområdena om att vara huvud-område. I PISA 2015 är naturvetenskap huvudområde för andra gången. Innehållet i PISA utformas utifrån ett ramverk som uppdateras varje gång kunskapsområdet är huvudområde. Denna rapport beskriver ramverket för naturvetenskap, läsförståelse och matematik och är en svensk sammanfattning av PISA 2015 Assessment and Analytical Framework. Science, Reading, Mathematic and Financial Literacy, som tagits fram av OECD. Rapporten innehåller också exempel på provuppgifter till eleverna. Rapporten är en bilaga till Skolverkets rapport 450, PISA 2015. 15-åringars kunskaper i naturvetenskap, läsförståelse och matematik, där några av de viktigaste resultaten från PISA 2015 presenteras med fokus på Sverige.Författarna till denna rapport är de forskare som ansvarat för naturveten-skap, läsförståelse och matematik i PISA 2015.Eva Lundgren på Skolverket har det övergripande ansvaret för PISA i Sverige. På Skolverkets uppdrag har PISA 2015 genomförts av Mittuniversitetet i samarbete med Stockholms universitet. Mittuniversitetet har haft det operativa ansvaret och även ansvarat för naturvetenskap medan Stockholms universitet ansvarat för matematik och läsförståelse. Magnus Oskarsson har varit nationell projektledare och har tillsammans med Maria Lundgren och Lena Lenner ansvarat för studiens praktiska genomförande. Magnus Oskarsson har också tillsammans med Nina Eliasson och K-G Karlsson ansvarat för naturvetenskap. Ulf Fredriksson och Maria Rasmusson har ansvarat för läsförståelse, samt Astrid Pettersson och Samuel Sollerman ansvarat för matematik.Skolverket vill rikta ett stort tack till alla som arbetat med PISA 2015 och framför allt till de cirka 5 500 elever som deltagit och till deras lärare och rektorer!
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| 7. |
- Rasmusson, Kristina, et al.
(författare)
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A simulation study of the effect of trapping model, geological heterogeneity and injection strategies on CO2 trapping
- 2016
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Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836 .- 1878-0148. ; 52, s. 52-72
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Tidskriftsartikel (refereegranskat)abstract
- Industrial CO2 emissions to the atmosphere can be reduced through geological storage, where the gas is injected into the subsurface and trapped by several mechanisms. Residual and solubility trapping are two important processes providing trapping, and their effectiveness ultimately determines the feasibility of geological storage. By means of numerical modeling, a systematic analysis was made concerning the factors potentially affecting trapping, to guide the planned injection experiments at the Heletz test injection site. The effect of enhanced-trapping injection strategies along with the role of geological heterogeneity and the choice of trapping model (TM) were evaluated. The results showed that adding chase-fluid stages to a conventional CO2 injection enhanced the trapping. Taking into account the geological heterogeneity decreased trapping, as this retarded the buoyant migration, resulting in less imbibition and residual trapping. The choice of TM was significant, with the simplified Land TM producing the highest trapping, and the Aissaoui TM the lowest. The results stress the importance of using an appropriate TM as well as heterogeneity model for the site in question for any predictive modeling of CO2 sequestration, as different assumptions may lead to significant discrepancies in the predicted trapping.
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| 8. |
- Rasmusson, Kristina, et al.
(författare)
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Analysis of alternative push-pull-test-designs for determining in situ residual trapping of carbon dioxide
- 2014
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Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836 .- 1878-0148. ; 27, s. 155-168
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Tidskriftsartikel (refereegranskat)abstract
- Carbon dioxide storage in deep saline aquifers is a promising technique to reduce direct emissions of greenhouse gas to the atmosphere. To ensure safe storage the in situ trapping mechanisms, residual trapping being one of them, need to be characterized. This study aims to compare three alternative single-well carbon dioxide push-pull test sequences for their ability to quantify residual gas trapping. The three tests are based on the proposed test sequence by Zhang et al. (2011) for estimating residual gas saturation. A new alternative way to create residual gas conditions in situ incorporating withdrawal and a novel indicator-tracer approach has been investigated. Further the value of additional pressure measurements from a nearby passive observation well was evaluated. The iTOUGH2 simulator with the EOS7C module was used for sensitivity analysis and parameter estimation. Results show that the indicator-tracer approach could be used to create residual conditions without increasing estimation uncertainty of S-gr. Additional pressure measurements from a passive observation well would reduce the uncertainty in the S-gr estimate. The findings of the study can be used to develop field experiments for site characterization.
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| 9. |
- Rasmusson, Kristina, et al.
(författare)
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Distribution of injected CO2 in a stratified saline reservoir accounting for coupled wellbore-reservoir flow
- 2015
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Ingår i: Greenhouse Gases. - : Wiley. - 2152-3878. ; 5:4, s. 419-436
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Tidskriftsartikel (refereegranskat)abstract
- Geological storage in sedimentary basins is considered a viable technology in mitigating atmospheric CO2 emissions. Alternating high and low permeability strata are common in these basins. The distribution of injected CO2 among such layers affects e.g. CO2 storage efficiency, capacity and plume footprint. A numerical study on the distribution of injected CO2 into a multi-layered reservoir, accounting for coupled wellbore-reservoir flow, was carried out using the T2Well/ECO2N code. A site-specific case as well as a more general case were considered. Properties and processes governing the distribution of sequestrated CO2 were identified and the potential to operationally modify the distribution was investigated. The distribution of CO2 was seen to differ from that of injected water, i.e. it was not proportional to the transmissivity of the layers. The results indicate that caution should be taken when performing numerical simulations of CO2 injection into layered formations. Ignoring coupled wellbore-reservoir flow and instead adopting a simple boundary condition at the injection well, such as an inflow rate proportional to the transmissivity of each layer, may result in significant underestimation of the proportion of CO2 ending up in the shallower layers, as not all relevant processes are accounted for. This discrepancy has been thoroughly investigated and quantified for several CO2 sequestration scenarios.
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| 10. |
- Rasmusson, Kristina, et al.
(författare)
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Exploring residual CO2 trapping in Heletz sandstone using pore-network modeling and a realistic pore-space topology obtained from a micro-CT scan
- 2021
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Ingår i: Greenhouse Gases. - : John Wiley & Sons. - 2152-3878. ; 11:5, s. 907-923
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Tidskriftsartikel (refereegranskat)abstract
- Geological storage of CO2 in deep saline aquifers mitigates atmospheric emissions. In situ storage is facilitated by several trapping mechanisms including residual trapping, which plays a major role in the containment of CO2. Understanding the underlying mechanisms of residual trapping is crucial for planning storage projects. Of special interest is the relationship between the initial and residual CO2 saturations-the so-called IR curve, needed for predictive macroscopic-scale simulations. This study aims to improve the understanding of residual trapping in sandstone from the Heletz site, where extensive field experiments have been performed, by using 3D-image analysis on core sample CT-data. This was done to gain knowledge on physical properties (such as radius, coordination number, aspect ratio, shape factor of pores, and pore connectivity) of importance to residual CO2 trapping. Pore-network flow modeling on a network representation, with the extracted pore-space topology, was employed to estimate the IR curve. The core sample exhibited pores with a large range of coordination numbers, a mean aspect ratio of 1.4, and shape factors mostly corresponding to triangular cross-sections. The estimated IR curve was monotonic, fitting an Aissaoui-type trapping model, displaying a lower sensitivity to the advancing contact angle than previously thought, and indicating a good ability to residually trap CO2. This study provides the first report of values for the three above mentioned properties for Heletz sandstone, and the first estimate of an IR curve for CO2/brine in Heletz sandstone based on pore-network modeling on a network with a topology retrieved from a core-sample CT-scan. (c) 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.
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