Density-Driven CO<sub>2</sub> Dissolution in Depleted Gas Reservoirs with Bottom Aquifers
Depleted gas reservoirs with bottom water show significant potential for long-term CO<sub>2</sub> storage. The residual gas influences mass-transfer dynamics, further affecting CO<sub>2</sub> dissolution and convection in porous media. In this study, we conducted a series of...
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| author | Xiaocong Lyu Fang Cen Rui Wang Huiqing Liu Jing Wang Junxi Xiao Xudong Shen |
| author_facet | Xiaocong Lyu Fang Cen Rui Wang Huiqing Liu Jing Wang Junxi Xiao Xudong Shen |
| author_sort | Xiaocong Lyu |
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| description | Depleted gas reservoirs with bottom water show significant potential for long-term CO<sub>2</sub> storage. The residual gas influences mass-transfer dynamics, further affecting CO<sub>2</sub> dissolution and convection in porous media. In this study, we conducted a series of numerical simulations to explore how residual-gas mixtures impact CO<sub>2</sub> dissolution trapping. Moreover, we analyzed the CO<sub>2</sub> dissolution rate at various stages and delineated the initiation and decline of convection in relation to gas composition, thereby quantifying the influence of residual-gas mixtures. The findings elucidate that the temporal evolution of the Sherwood number observed in the synthetic model incorporating CTZ closely parallels that of the single-phase model, but the order of magnitude is markedly higher. The introduction of CTZ serves to augment gravity-induced convection and expedites the dissolution of CO<sub>2</sub>, whereas the presence of residual-gas mixtures exerts a deleterious impact on mass transfer. The escalation of residual gas content concomitantly diminishes the partial pressure and solubility of CO<sub>2</sub>. Consequently, there is an alleviation of the concentration and density differentials between saturated water and fresh water, resulting in the attenuation of the driving force governing CO<sub>2</sub> diffusion and convection. This leads to a substantial reduction in the rate of CO<sub>2</sub> dissolution, primarily governed by gravity-induced fingering, thereby manifesting as a delay in the onset and decay time of convection, accompanied by a pronounced decrement in the maximum Sherwood number. In the field-scale simulation, the injected CO<sub>2</sub> improves the reservoir pressure, further pushing more gas to the producers. However, due to the presence of CH<sub>4</sub> in the post-injection process, the capacity for CO<sub>2</sub> dissolution is reduced. |
| format | Article |
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| institution | Kabale University |
| issn | 1996-1073 |
| language | English |
| publishDate | 2024-07-01 |
| publisher | MDPI AG |
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| series | Energies |
| spelling | doaj-art-3e7ecbe6922a4b20afae56dc30f27bf02025-01-10T16:28:45ZengMDPI AGEnergies1996-10732024-07-011714349110.3390/en17143491Density-Driven CO<sub>2</sub> Dissolution in Depleted Gas Reservoirs with Bottom AquifersXiaocong Lyu0Fang Cen1Rui Wang2Huiqing Liu3Jing Wang4Junxi Xiao5Xudong Shen6State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 102206, ChinaState Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 102206, ChinaState Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 102206, ChinaState Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, ChinaState Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, ChinaState Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, ChinaState Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, ChinaDepleted gas reservoirs with bottom water show significant potential for long-term CO<sub>2</sub> storage. The residual gas influences mass-transfer dynamics, further affecting CO<sub>2</sub> dissolution and convection in porous media. In this study, we conducted a series of numerical simulations to explore how residual-gas mixtures impact CO<sub>2</sub> dissolution trapping. Moreover, we analyzed the CO<sub>2</sub> dissolution rate at various stages and delineated the initiation and decline of convection in relation to gas composition, thereby quantifying the influence of residual-gas mixtures. The findings elucidate that the temporal evolution of the Sherwood number observed in the synthetic model incorporating CTZ closely parallels that of the single-phase model, but the order of magnitude is markedly higher. The introduction of CTZ serves to augment gravity-induced convection and expedites the dissolution of CO<sub>2</sub>, whereas the presence of residual-gas mixtures exerts a deleterious impact on mass transfer. The escalation of residual gas content concomitantly diminishes the partial pressure and solubility of CO<sub>2</sub>. Consequently, there is an alleviation of the concentration and density differentials between saturated water and fresh water, resulting in the attenuation of the driving force governing CO<sub>2</sub> diffusion and convection. This leads to a substantial reduction in the rate of CO<sub>2</sub> dissolution, primarily governed by gravity-induced fingering, thereby manifesting as a delay in the onset and decay time of convection, accompanied by a pronounced decrement in the maximum Sherwood number. In the field-scale simulation, the injected CO<sub>2</sub> improves the reservoir pressure, further pushing more gas to the producers. However, due to the presence of CH<sub>4</sub> in the post-injection process, the capacity for CO<sub>2</sub> dissolution is reduced.https://www.mdpi.com/1996-1073/17/14/3491CO<sub>2</sub> sequestrationdepleted gas reservoirresidual-gas mixturedissolution trappingcapillary transition zone |
| spellingShingle | Xiaocong Lyu Fang Cen Rui Wang Huiqing Liu Jing Wang Junxi Xiao Xudong Shen Density-Driven CO<sub>2</sub> Dissolution in Depleted Gas Reservoirs with Bottom Aquifers Energies CO<sub>2</sub> sequestration depleted gas reservoir residual-gas mixture dissolution trapping capillary transition zone |
| title | Density-Driven CO<sub>2</sub> Dissolution in Depleted Gas Reservoirs with Bottom Aquifers |
| title_full | Density-Driven CO<sub>2</sub> Dissolution in Depleted Gas Reservoirs with Bottom Aquifers |
| title_fullStr | Density-Driven CO<sub>2</sub> Dissolution in Depleted Gas Reservoirs with Bottom Aquifers |
| title_full_unstemmed | Density-Driven CO<sub>2</sub> Dissolution in Depleted Gas Reservoirs with Bottom Aquifers |
| title_short | Density-Driven CO<sub>2</sub> Dissolution in Depleted Gas Reservoirs with Bottom Aquifers |
| title_sort | density driven co sub 2 sub dissolution in depleted gas reservoirs with bottom aquifers |
| topic | CO<sub>2</sub> sequestration depleted gas reservoir residual-gas mixture dissolution trapping capillary transition zone |
| url | https://www.mdpi.com/1996-1073/17/14/3491 |
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