Speaker
Description
Underground hydrogen storage (UHS) in geological formations is a promising method for storing hydrogen, with cycles of hydrogen injection and withdrawal typically anticipated for long-term development. However, the impact of local capillary trapping on the amount of hydrogen that can be stored and recovered over the entire period remains unclear. Furthermore, the selection of a suitable reservoir for UHS is still a subject of debate. To address these issues, we develop a coupled level-set interface tracking and pore network model to assess potential factors influencing UHS efficiency. Digital rock models of various rock types are obtained using CT imaging. We then simulate two cycles of UHS in water-saturated rocks (injection-withdrawal-injection-withdrawal) based on these digital rocks. Pearson correlation is used to quantify the relationships between hydrogen storage volume ratio, storage efficiency, and dimensionless pore structure parameters. Our results show that the trapped hydrogen volume ratio is primarily correlated with pore connectivity parameters, with little relation to connected porosity. Based on this correlation, a fitting equation for hydrogen storage efficiency is derived, which can be easily integrated with well-logging data to help select the most favorable formation for UHS. A comparison of UHS efficiency across different rock types reveals that the efficiency is often overestimated, as the maximum hydrogen storage efficiency in our study is less than 0.8. Finally, we conclude that sandstone reservoirs are more suitable for UHS than carbonate or shale reservoirs.
| Country | China |
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