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- Basirat, Farzad, et al.
(författare)
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Characterization of CO2 self-release during Heletz Residual Trapping Experiment I (RTE I) using a coupled wellbore-reservoir simulator
- 2020
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Ingår i: International Journal of Greenhouse Gas Control. - : ELSEVIER SCI LTD. - 1750-5836 .- 1878-0148. ; 102
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Tidskriftsartikel (refereegranskat)abstract
- In order to quantify CO2 residual trapping in situ, two dedicated single-well push-pull experiments have been carried out at the Heletz, Israel pilot CO2 injection site. Field data from some parts of these experiments suggests the important effect of the hydrodynamic behavior in the injection-withdrawal well. In the present work a model capturing the CO2 transport and trapping behavior during Heletz Residual Trapping Experiment I is developed, with a special focus on coupled wellbore-reservoir flow. The simulation is carried out with the numerical simulator T2Well/ECO2N (Pan et al. 2011) which considers the wellbore-reservoir coupling. Of particular interest is to accurately model the period when the well is open to the atmosphere and self-producing CO2 and water in a geyser-like manner. It is also of interest to identify what conditions are causing the oscillating pressure-temperature behavior and the associated periodic gas-liquid releases, as well as to determine the amount of gas lost from the reservoir during this period. The results suggest that the behavior is due to cyclical CO2 exsolution from the aqueous phase along with a reduction of mobility of both CO2 and brine in the near wellbore-reservoir area, the latter being due to a zone of dispersed CO2 bubbles near the wellbore. This behavior could be successfully captured with a new set of relative permeability functions developed earlier for CO2 exsolution in laboratory experiments (Zuo et al., 2013).
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| 3. |
- Basirat, Farzad, et al.
(författare)
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Pore-scale modeling of wettability effects on CO2-brine displacement during geological storage
- 2016
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Konferensbidrag (refereegranskat)abstract
- Wetting properties of reservoir rocks and caprocks can significantly influence on sequestration of carbon dioxide in deep geological formations. Wettability impacts on the physical and chemical processes that are associated with injecting CO2 underground. Our aim is to understand how wetting properties influence two-phase flow of CO2 and brine in a pore scale domain. We use the phase field method to simulate the two-phase flow of CO2-brine in realistic porous domain geometry. Our focus is on clarifying the pore-scale fluid-fluid displacement mechanisms under different wetting conditions and to quantifying the effect of contact angle on macroscopic parameters such as residual brine saturation, capillary pressure, and specific interfacial area. We could show the phase field method can be applied to a complex porous medium with realistic reservoir permeability. Beside it was shown that it can deal with the conditions with large viscosity contrasts and large wettability (low contact angles) which are difficult to handle with direct numerical approaches. Our simulations results suggest wettability concept cannot be explained just by contact angles. Even though the wettability in pore-scale is defined as the contact angle, there is not any particular relation to link the contact angle to the residual saturations and distribution patterns of CO2 in porous domain. Beside the contact angle, the flow rate and basic properties of fluids which are represent in capillary number and mobility number definitions and also the geometry of porous media are describe the CO2-brine distributions.
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| 4. |
- Basirat, Farzad, et al.
(författare)
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Pore-scale modeling of wettability effects on CO2–brine displacement during geological storage
- 2017
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Ingår i: Advances in Water Resources. - : Elsevier. - 0309-1708 .- 1872-9657. ; 109, s. 181-195
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Tidskriftsartikel (refereegranskat)abstract
- Wetting properties of reservoir rocks and caprocks can vary significantly, and they strongly influence geological storage of carbon dioxide in deep saline aquifers, during which CO2 is supposed to displace the resident brine and to become permanently trapped. Fundamental understanding of the effect of wettability on CO2-brine displacement is thus important for improving storage efficiency and security. In this study, we investigate the influence of wetting properties on two-phase flow of CO2 and brine at the pore scale. A numerical model based on the phase field method is implemented to simulate the two-phase flow of CO2-brine in a realistic pore geometry. Our focus is to study the pore-scale fluid-fluid displacement mechanisms under different wetting conditions and to quantify the effect of wettability on macroscopic parameters such as residual brine saturation, capillary pressure, relative permeability, and specific interfacial area. Our simulation results confirm that both the trapped wetting phase saturation and the normalized interfacial area increase with decreasing contact angle. However, the wetting condition does not appear to influence the CO2 breakthrough time and saturation. We also show that the macroscopic capillary pressures based on the pressure difference between inlet and outlet can differ significantly from the phase averaging capillary pressures for all contact angles when the capillary number is high ( log Ca > -5). This indicates that the inlet-outlet pressure difference may not be a good measure of the continuum-scale capillary pressure. In addition, the results show that the relative permeability of CO2 can be significantly lower in strongly water-wet conditions than in the intermediate-wet conditions.
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| 10. |
- Joodaki, Saba, et al.
(författare)
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Model analysis of CO2 residual trapping from single-well push pull test based on hydraulic withdrawal tests : Heletz, residual trapping experiment I
- 2020
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Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836 .- 1878-0148. ; 97
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Tidskriftsartikel (refereegranskat)abstract
- Residual or capillary trapping is one of the key trapping mechanisms for geological storage of CO2. Yet, very few studies so far have attempted to estimate the residual trapping and the related characteristic parameter, residual saturation, in situ. At Heletz, a pilot CO2 injection site in Israel a single-well push-pull experiment to estimate residual gas saturation in situ was carried out during autumn 2016. The main characterization method was hydraulic withdrawal tests. The residually trapped zone was also created by means of fluid withdrawal, by first injecting CO2 and then withdrawing fluids leaving behind the immobile residual CO2. This paper presents the first model interpretation of the experimental results. Numerical modeling with TOUGH2/ECO2N was carried out to model the entire test sequence, the focus being in matching the collected pressure, temperature and flow data as well as observations of gas content in the borehole. The experimental results could be well fitted with the model that also is in agreement with previously collected petro-physical data. The results indicate a somewhat lower residual gas saturation than that measured in the laboratory, the estimated maximum residual saturation from the field experiment being 10% and the corresponding value from the core 20%. The results also indicate that most of the CO2 entered the upper reservoir layer, thus actually giving an estimate of the effective residual trapping in that layer. Overall, pressure response gave a clear signal and was an effective method in getting an estimate of the effective residual trapping in the interval tested.
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