The sealing evaluation of underground hydrogen storage cap rock in aquifer: Taking Y water-bearing trap as an example

Based on the key indicators affecting the seal performance of aquifer gas storage at home and abroad, the seal evaluation system of aquifer underground hydrogen storage trap is constructed, and the evaluation method suitable for the seal performance of aquifer cover in China-analytic hierarchy process is analyzed. The static sealing capacity of Y water-bearing trap cap in an oil and gas area in East China is qualitatively analyzed by combining analytic hierarchy process (AHP) and multi-factor comprehensive evaluation method. The results show that: ① Traditional factors such as direct cap thickness and rock brittleness account for a relatively high proportion in the static seal evaluation system, followed by special factors such as formation water acidity and mineral type. ② Based on the analysis of analytic hierarchy process (AHP) and multi-factor comprehensive evaluation, it can be seen that the cap layer of Y water-bearing trap has a certain gas sealing ability under static conditions, which can seal off the hydrogen in the reservoir to a certain extent and avoid the escape of hydrogen. The research shows that the evaluation system can provide some guidance and theoretical basis for the preliminary evaluation of the sealing property of the underground hydrogen storage cover of aquifers.