Underground hydrogen (H) storage in saline aquifers is a viable solution for large-scale H storage. Due to its remarkably low viscosity and density, the flow of H within saline aquifers exhibits strong instability, which needs to be thoroughly investigated to ensure safe operations at the storage site. For the first time, we develop a lattice Boltzmann model tailored for pore-scale simulations of the H-brine system under typical subsurface storage conditions. The model captures the significant contrast of fluid properties between H and brine, and it offers the flexibility to adjust the contact angle to suit varying wetting conditions. We show that the snap-off is enhanced in a system with a high capillary number and a small contact angle. These conditions lead to a low recovery factor, which is unfavorable for H production from the aquifer. Moreover, the relative permeability curves, computed from the simulation results, exhibit distinct behaviors for H and brine. In the case of the wetting phase, the relative permeability can be quantified using the quadratic expression, whereas for the non-wetting phase, the relative permeability exhibits a nearly linear behavior, and saturation alone appears insufficient to characterize the relative permeability at large saturations of non-wetting phase. This implies that different formula for liquid and gas phases may be employed for continuum-scale simulations.

中文翻译：

---

与地下储氢相关的氢气-盐水系统的孔隙尺度模拟：格子玻尔兹曼研究


咸水层中的地下储氢是大规模储氢的可行解决方案。由于其粘度和密度极低，H在咸水含水层中的流动表现出很强的不稳定性，需要对其进行彻底研究以确保储存地点的安全操作。我们首次开发了一种晶格玻尔兹曼模型，专为典型地下储存条件下氢气系统的孔隙尺度模拟而设计。该模型捕捉了 H 和盐水之间流体特性的显着对比，并且可以灵活地调整接触角以适应不同的润湿条件。我们表明，在具有高毛细管数和小接触角的系统中，折断得到增强。这些条件导致采收率较低，不利于含水层的氢气生产。此外，根据模拟结果计算的相对渗透率曲线表现出 H 和盐水的不同行为。在润湿相的情况下，相对渗透率可以使用二次表达式来量化，而对于非润湿相，相对渗透率表现出接近线性的行为，并且单独的饱和度似乎不足以表征大饱和度下的相对渗透率。非润湿阶段。这意味着可以采用不同的液相和气相公式进行连续尺度模拟。