Impact of pore heterogeneity on CO2 capture efficiency in porous media

Capture and sequestration of CO2 in porous geological formations is one of the most important ways to achieve low carbon development and combat climate change. The flow of fluids in porous media is affected by a variety of factors. Currently, research on flow in porous media focuses on the effects of fluid properties and often overlooks the heterogeneity of porous structure at the microscopic scale. However, pore structure at the microscopic level is the basic factor that determines the macroscopic physical properties. To clarify the impact of pore heterogeneity on CO2 capture efficiency in porous media, we propose to characterize the different pore structures by porosity and the probability density (PD) function of pore size. Then, based on microfluidics, three different porous structures were subjected to displacement and re-imbibition experiments and discussed the impact of structure on CO2 saturation. The experiment results show that the pore size and distribution are the most crucial features that decide the capture efficiency of the porous structure, and heterogeneous small poredominated structures possess greater capture efficiency due to the formation of small pore-enclosing structures. Porosity has relatively minor impact. Additionally, heterogeneity may alter flow patterns.