Numerical evaluation of fingering behavior for hydrogen in aquifers

Underground hydrogen storage emerges as a strategy to address the challenge of large-scale, long-term, and economically viable hydrogen preservation, fulfilling energy demands and balancing supply discrepancies in renewable energy frameworks. This study is motivated to investigate and evaluate the fingering behavior during the hydrogen injection process. Numerical cases are performed to evaluate different simulation scenarios and sensitive influencing factors, such as fluid-rock interaction parameters and formation heterogeneity cases, on the influence of fingering flow. Different mesh upscaling schemes are compared to computational efficiency in the scale-up hydrogen injection process. Results show that fingering flow can indeed be induced during the hydrogen injection process due to the difference in flow capability between hydrogen and saline water. The characteristics of fingering flow significantly impact the performance of hydrogen displacement in saline aquifers. The hydrogen displacement path in the saline aquifer is highly sensitive to variations in the autocorrelation length. Compared to the averaging upscaling scenario, the same-statistic upscaling scenario can prevent a significant loss of numerical simulation characteristics.