We combine modeling and measurements to investigate the dynamics of convective carbon dioxide (CO${}_2$) dissolution in a pressure-volume-temperature cell, extending a recent study by Wen et al. (J. Fluid Mech., vol. 854, 2018, pp. 56–87) at low-pressure under ideal-gas conditions to high-pressure and real-gas conditions. Pressure-dependent compressibility and solubility are included to model the evolution of CO${}_2$ concentration in the gas phase and at the interface, respectively. Simple ordinary-differential-equation models are developed to capture the mean behavior of the convecting system at large Rayleigh number and are then verified by using both numerical simulations and laboratory experiments. The prefactor for the linear scaling of convective CO${}_2$ dissolution is evaluated – for the first time – by using pressure-decay experiments in bead packs at reservoir conditions. The results show that our models could quantitatively predict the process of the convective CO${}_2$ dissolution in pressure-decay experiments. Moreover, the results also reveal that for increasing gas pressure in closed systems, the negative feedback of the pressure drop – resulting from the dissolution of CO${}_2$ in the liquid – is weakened due to the decrease of the solubility constant at real-gas conditions. Our analysis provides a new direction for determination and validation of the convective dissolution flux of CO${}_2$ in porous media systems.

我们结合建模和测量来研究对流二氧化碳 (CO${}_2$) 在压力-体积-温度单元中溶解，扩展了Wen等人最近的一项研究。( J. Fluid Mech. , vol. 854, 2018, pp. 56–87) 在理想气体条件下的低压到高压和真实气体条件下。包括与压力相关的可压缩性和溶解度以模拟 CO 的演变${}_2$分别在气相和界面处的浓度。开发了简单的普通微分方程模型来捕捉大瑞利数下对流系统的平均行为，然后通过使用数值模拟和实验室实验进行验证。对流 CO 线性缩放的前置因子${}_2$溶出度是首次通过在储层条件下的珠子组中使用压力衰减实验进行评估。结果表明，我们的模型可以定量预测 CO 的对流过程${}_2$在压力衰减实验中溶解。此外，结果还表明，对于增加封闭系统中的气体压力，压降的负反馈——由 CO 的溶解引起${}_2$在液体中 - 由于真实气体条件下溶解度常数的降低而减弱。我们的分析为确定和验证 CO 的对流溶解通量提供了新的方向${}_2$ 在多孔介质系统中。