A Fully Coupled Hydromechanical Model for CO2Sequestration in Coal Seam: the Roles of Multiphase Flow and Gas Dynamic Diffusion on Fluid Transfer and Coal Behavior
| Autor: | Yongjie Yang, Rui Yang, Rui Zhou, Junhe Xie, Weiqun Liu, Tianran Ma, Yang Hu |
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| Rok vydání: | 2020 |
| Předmět: |
QE1-996.5
Petroleum engineering business.industry Multiphase flow Flow (psychology) 0211 other engineering and technologies Coal mining Geology 02 engineering and technology Carbon sequestration 020401 chemical engineering Fracture (geology) General Earth and Planetary Sciences Gaseous diffusion Environmental science Coal 021108 energy 0204 chemical engineering Diffusion (business) business |
| Zdroj: | Geofluids, Vol 2020 (2020) |
| ISSN: | 1468-8123 1468-8115 |
| DOI: | 10.1155/2020/8871614 |
| Popis: | CO2sequestration in coal seam has proved to be an effective way for reducing air pollution caused by greenhouse gases. A study on the rules of fluid transfer and reliability of CO2storage during gas injection is necessary for the engineering application. However, the clarification of multifield coupling in long-term CO2sequestration is the difficulty to solve the aforementioned problem. Previous investigations on the coupled model for CO2storage in coal seam were not exactly comprehensive; for example, the multiphase flow in the fracture and the nonlinear behavior of gas diffusion were generally neglected. In this paper, a new multistage pore model of the coal matrix and the corresponding dynamic diffusion model were adopted. Meanwhile, the CO2-induced coal softening and the CO2-water two-phase flow in coal fracture were also taken into account. Subsequently, all the mentioned mechanisms and interactions were embedded into the coupled hydromechanical model, and this new fully coupled model was well verified by a set of experimental data. Additionally, through the model application for long-term CO2sequestration, we found that the stored CO2molecules are mainly in an adsorbed state at the early injection stage, while with the continuous injection of gas, the stored CO2molecules are mainly in a free state. Finally, the roles of multiphase flow and gas dynamic diffusion on fluid transfer and coal behavior were analyzed. The results showed that the impact of multiphase flow is principally embodied in the area adjacent to the injection well and the coal seam with lower initial water saturation is more reliable for CO2sequestration, while the impact of gas dynamic diffusion is principally embodied in the area far away from the injection well, and it is safer for CO2sequestration in coal seam with greater attenuation coefficient of CO2diffusion. |
| Databáze: | OpenAIRE |
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