Biomimetic microfluidic chip fabrication for studying fluid transport in micro- and nanoscale carbonate rock fracture

The flow of fluids between minerals involves complex physicochemical coupling effects, and using real rock cores as reactors for characterization presents significant challenges. This is due to the lack of fluid visualization capabilities in rock cores, as well as their highly heterogeneous structure. This study introduces a biomimetic microfluidic chip fabrication method that enables the direct observation of fluid-mineral interactions at the micro- and nanoscale, with the added benefit of scalability for mass production. The fabrication process starting with machine learning algorithms are employed to extract fracture structures from natural rock samples; second, soft lithography is utilized to replicate these fractures at a 1:1 scale; and finally, the fracture surfaces are modified through in situ growth of calcium carbonate minerals, thereby creating high-fidelity models of carbonate rock fractures for fluid transport. Notably, this method offers tunable parameters for key variables, such as porous structures, mineral types, and the physicochemical properties of mineral surfaces. This makes it an ideal platform for in-depth studies of fluid transport mechanisms under complex conditions, such as the sealing effects of chemical agents on fractures or the migration of oil and gas in reservoirs.