| 1. |
- 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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| 2. |
- 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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