Lattice Boltzmann simulation of CO₂ reactive transport in network fractured media

Carbon dioxide (CO₂) geological sequestration plays an important role in mitigating CO₂ emissions for climate change. Understanding interactions of the injected CO₂ with network fractures and hydrocarbons is key for optimizing and controlling CO₂ geological sequestration and evaluating its risks to ground water. However, there is a well-known, difficult process in simulating the dynamic interaction of fracture-matrix, such as dynamic change of matrix porosity, unsaturated processes in rock matrix, and effect of rock mineral properties. In this paper, we develop an explicit model of the fracture-matrix interactions using multilayer bounce-back treatment as a first attempt to simulate CO₂ reactive transport in network fractured media through coupling the Dardis's LBM porous model for a new interface treatment. Two kinds of typical fracture networks in porous media are simulated: straight cross network fractures and interleaving network fractures. The reaction rate and porosity distribution are illustrated and well-matched patterns are found. The species concentration distribution and evolution with time steps are also analyzed and compared with different transport properties. The results demonstrate the capability of this model to investigate the complex processes of CO₂ geological injection and reactive transport in network fractured media, such as dynamic change of matrix porosity.