Nanoscale spontaneous imbibition is a common process in nanoporous soil and unconventional reservoirs. Due to the complexity of these natural nanoporous media, the relevant spontaneous imbibition dynamics are still unclear. Thus, this paper studies spontaneous imbibition dynamics of liquids into a nanoporous carbon scaffold (NCS, with controllable wettability and pore geometry). The effects of evaporation and surfactant on spontaneous imbibition are also examined. For low-volatility liquids, a linear relationship between spontaneous imbibition height (\(H\)) and square root of time (\(\sqrt{t}\)) is observed. A modified Lucas–Washburn (L–W) equation is developed to describe the corresponding dynamics and to predict the NCS effective radius and the advancing water contact angle. A dimensionless time function is presented, which includes the properties of solid and liquid and their interactions, and can be used for upscaling spontaneous imbibition data in nanoporous media from laboratory to reservoir scales. Both a larger NCS pore diameter and pore throat diameter cause faster imbibition. The addition of surfactant into an aqueous solution increases the imbibition rate, although this influence is suppressed with pore size decrease. In contrast, for high-volatility liquids, a significant deviation from the linear relationship between \(H\) and \(\sqrt{t}\) is found at late times. The modified L–W equation is further developed to include evaporation effect. This study thus provides fundamental understanding of spontaneous imbibition dynamics at nanoscales. The developed theoretical models are expected to be applicable to important problems such as water infiltration into soil, fracturing fluid loss in unconventional reservoirs, and electrolyte migration in electrochemical devices.

纳米级自吸是纳米多孔土壤和非常规储层中的常见过程。由于这些天然纳米多孔介质的复杂性，相关的自发吸收动力学仍然不清楚。因此，本文研究了液体自发吸收到纳米多孔碳支架（NCS，具有可控的润湿性和孔隙几何形状）中的动力学。还检查了蒸发和表面活性剂对自吸的影响。对于低挥发性液体，自发吸收高度（\（H \））与时间的平方根（\（\ sqrt {t} \）之间是线性关系）被观察到。修改后的Lucas-Washburn（L-W）方程用于描述相应的动力学并预测NCS有效半径和前进的水接触角。提出了无量纲的时间函数，其中包括固体和液体的性质及其相互作用，可用于将纳米多孔介质中的自吸数据从实验室规模扩展到储层规模。较大的NCS孔径和孔喉直径都会导致更快的吸收。尽管在减小孔径的情况下可以抑制这种影响，但是在水溶液中添加表面活性剂可以提高吸收率。相反，对于高挥发性液体，\（H \）和\（\ sqrt {t} \）之间的线性关系存在显着偏差被发现在较晚的时间。修改后的LW方程进一步发展为包括蒸发效应。因此，这项研究为纳米级的自发吸收动力学提供了基本的了解。预期开发的理论模型将适用于重要问题，例如水渗入土壤，非常规储层中的压裂液损失以及电化学装置中的电解质迁移。