Speaker
Description
Injecting CO2 into coal reservoirs has the dual benefits of not only enhancing coalbed methane recovery but also achieving geological storage of CO2 to reduce greenhouse gas emissions. Deep coal reservoirs are usually saturated with water, and CO2 is usually in a supercritical state under high pressure and temperature at deep burial depths. Understanding the structural changes in deep coal reservoirs after CO2 injection is important for the effectiveness, safety, and economy of carbon geological sequestration (CGS).
This study aims to: (1) analyze the influence of coal surface roughness on flow efficiency during CO2 injection. The fractal characteristics of pore-fracture structure are accurately presented by the box-counting method, and the relationship between surface roughness and effective porosity is clarified. (2) Evaluate the control of coal pore-fracture structure parameters on CO2 flow. Morphological algorithms are used to characterize the topological characteristics of pore-fracture structure, and the effect of pore/throat diameter, coordination number, tortuosity, and sphericity on CO2 permeability is discussed. (3) Reveal the response mechanism of pore-fracture structure changes due to mineral dissolution in CO2-H2O-coal interaction. The response mode of pore-fracture structure caused by mineral dissolution during CO2 injection in coal is established by comparing the change in coordination number of pore-fracture structure before and after CO2-H2O interaction. This study provides insights into the flow characteristics of CO2 sequestration in deep coal reservoirs and contributes to optimizing the storage strategies for CGS.
Keywords: Coal, 3D reconstruction, Pore network model, CO2 flow simulation, Carbon geological sequestration
| References | (1) Cheng, Q., Zhou, S., Elsworth, D., Cui, G., Jing, Y. and Yan, D., 2025. Key role of CO2 thermophysical properties and phase behavior in coal: Optimizing CH4 recovery and CO2 geosequestration. Energy, 339: 139000. https://doi.org/https://doi.org/10.1016/j.energy.2025.139000. (2) Liu, D., Zhao, Z., Cai, Y., Sun, F. and Zhou, Y., 2022. Review on applications of X-ray computed tomography for coal characterization: Recent progress and perspectives. Energy & Fuels, 36(13): 6659-6674. https://doi.org/10.1021/acs.energyfuels.2c01147. (3) Salmachi, A., Zeinijahromi, A., Algarni, M.S., Abahussain, N.A., Alqahtani, S.A., Badalyan, A., Rezaee, M. and Rajabi, M., 2023. Experimental study of the impact of CO2 injection on the pore structure of coal: A case study from the Bowen Basin, Australia. International Journal of Coal Geology, 275: 104314. https://doi.org/10.1016/j.coal.2023.104314. (4) Sampath, K.H.S.M., Perera, M.S.A., Ranjith, P.G. and Matthai, S.K., 2019. CO2 interaction induced mechanical characteristics alterations in coal: A review. International Journal of Coal Geology, 204: 113-129. https://doi.org/10.1016/j.coal.2019.02.004. (5) Schmitt Rahner, M., Halisch, M., Peres Fernandes, C., Weller, A. and Sampaio Santiago dos Santos, V., 2018. Fractal dimensions of pore spaces in unconventional reservoir rocks using X-ray nano- and micro-computed tomography. Journal of Natural Gas Science and Engineering, 55: 298-311. https://doi.org/10.1016/j.jngse.2018.05.011. |
|---|---|
| Country | China |
| Acceptance of the Terms & Conditions | Click here to agree |
