Semi-Analytical Solution to Assess CO<sub>2</sub> Leakage in the Subsurface through Abandoned Wells
Geological carbon storage is an effective method capable of reducing carbon dioxide (CO<sub>2</sub>) emissions at significant scales. Subsurface reservoirs with sealing caprocks can provide long-term containment for the injected fluid. Nevertheless, CO<sub>2</sub> leakage is...
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MDPI AG
2021-04-01
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| Online Access: | https://www.mdpi.com/1996-1073/14/9/2452 |
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| author | Tian Qiao Hussein Hoteit Marwan Fahs |
| author_facet | Tian Qiao Hussein Hoteit Marwan Fahs |
| author_sort | Tian Qiao |
| collection | DOAJ |
| description | Geological carbon storage is an effective method capable of reducing carbon dioxide (CO<sub>2</sub>) emissions at significant scales. Subsurface reservoirs with sealing caprocks can provide long-term containment for the injected fluid. Nevertheless, CO<sub>2</sub> leakage is a major concern. The presence of abandoned wells penetrating the reservoir caprock may cause leakage flow-paths for CO<sub>2</sub> to the overburden. Assessment of time-varying leaky wells is a need. In this paper, we propose a new semi-analytical approach based on pressure-transient analysis to model the behavior of CO<sub>2</sub> leakage and corresponding pressure distribution within the storage site and the overburden. Current methods assume instantaneous leakage of CO<sub>2</sub> occurring with injection, which is not realistic. In this work, we employ the superposition in time and space to solve the diffusivity equation in 2D radial flow to approximate the transient pressure in the reservoirs. Fluid and rock compressibilities are taken into consideration, which allow calculating the breakthrough time and the leakage rate of CO<sub>2</sub> to the overburden accurately. We use numerical simulations to verify the proposed time-dependent semi-analytical solution. The results show good agreement in both pressure and leakage rates. Sensitivity analysis is then conducted to assess different CO<sub>2</sub> leakage scenarios to the overburden. The developed semi-analytical solution provides a new simple and practical approach to assess the potential of CO<sub>2</sub> leakage outside the storage site. This approach is an alternative to numerical methods when detailed simulations are not feasible. Furthermore, the proposed solution can also be used to verify numerical codes, which often exhibit numerical artifacts. |
| first_indexed | 2024-03-10T11:57:41Z |
| format | Article |
| id | doaj.art-2748654a675d4f958a97e53af342cc00 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T11:57:41Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-2748654a675d4f958a97e53af342cc002023-11-21T17:07:47ZengMDPI AGEnergies1996-10732021-04-01149245210.3390/en14092452Semi-Analytical Solution to Assess CO<sub>2</sub> Leakage in the Subsurface through Abandoned WellsTian Qiao0Hussein Hoteit1Marwan Fahs2Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi ArabiaPhysical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi ArabiaInstitut Terre et Environnement de Strasbourg, Université de Strasbourg, CNRS, ENGEES, UMR 7063, 67081 Strasbourg, FranceGeological carbon storage is an effective method capable of reducing carbon dioxide (CO<sub>2</sub>) emissions at significant scales. Subsurface reservoirs with sealing caprocks can provide long-term containment for the injected fluid. Nevertheless, CO<sub>2</sub> leakage is a major concern. The presence of abandoned wells penetrating the reservoir caprock may cause leakage flow-paths for CO<sub>2</sub> to the overburden. Assessment of time-varying leaky wells is a need. In this paper, we propose a new semi-analytical approach based on pressure-transient analysis to model the behavior of CO<sub>2</sub> leakage and corresponding pressure distribution within the storage site and the overburden. Current methods assume instantaneous leakage of CO<sub>2</sub> occurring with injection, which is not realistic. In this work, we employ the superposition in time and space to solve the diffusivity equation in 2D radial flow to approximate the transient pressure in the reservoirs. Fluid and rock compressibilities are taken into consideration, which allow calculating the breakthrough time and the leakage rate of CO<sub>2</sub> to the overburden accurately. We use numerical simulations to verify the proposed time-dependent semi-analytical solution. The results show good agreement in both pressure and leakage rates. Sensitivity analysis is then conducted to assess different CO<sub>2</sub> leakage scenarios to the overburden. The developed semi-analytical solution provides a new simple and practical approach to assess the potential of CO<sub>2</sub> leakage outside the storage site. This approach is an alternative to numerical methods when detailed simulations are not feasible. Furthermore, the proposed solution can also be used to verify numerical codes, which often exhibit numerical artifacts.https://www.mdpi.com/1996-1073/14/9/2452CO<sub>2</sub> storageCCSanalytical solutionleakagepressure transient analysisabandoned wells |
| spellingShingle | Tian Qiao Hussein Hoteit Marwan Fahs Semi-Analytical Solution to Assess CO<sub>2</sub> Leakage in the Subsurface through Abandoned Wells Energies CO<sub>2</sub> storage CCS analytical solution leakage pressure transient analysis abandoned wells |
| title | Semi-Analytical Solution to Assess CO<sub>2</sub> Leakage in the Subsurface through Abandoned Wells |
| title_full | Semi-Analytical Solution to Assess CO<sub>2</sub> Leakage in the Subsurface through Abandoned Wells |
| title_fullStr | Semi-Analytical Solution to Assess CO<sub>2</sub> Leakage in the Subsurface through Abandoned Wells |
| title_full_unstemmed | Semi-Analytical Solution to Assess CO<sub>2</sub> Leakage in the Subsurface through Abandoned Wells |
| title_short | Semi-Analytical Solution to Assess CO<sub>2</sub> Leakage in the Subsurface through Abandoned Wells |
| title_sort | semi analytical solution to assess co sub 2 sub leakage in the subsurface through abandoned wells |
| topic | CO<sub>2</sub> storage CCS analytical solution leakage pressure transient analysis abandoned wells |
| url | https://www.mdpi.com/1996-1073/14/9/2452 |
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