Numerical Investigation of Binary Fluid Flow through Propped Fractures by Lattice Boltzmann Method

Abstract

In this paper, a pore-scale multiphase, multicomponent Shan–Chen model with proper pressure boundary scheme is developed and implemented to model binary flows in porous media, which enables us to reveal the displacement mechanism of binary flows in hydraulic fractures filled with proppant of different sizes. Each fluid is represented by a lattice with different particle distribution functions. The pressure boundary scheme should be carefully approached to avoid numerical instabilities, because two interrelated lattices coexist in the same computational domain. The present model is validated and calibrated by the bubble test and the static contact angle test. In addition, based on this model, the two-component displacement is investigated, which is of great importance to the petroleum industry CO2 sequestration, subsurface energy storage, and waste landfill,. It involves complex flow mechanism affected by a variety of factors. In this study, only two factors are considered and studied: the wettability of binary fluids and the pore structures of propped fractures obtained from our previous studies. To evaluate the displacement performance in detail, three evaluation parameters, including breakthrough time, displacement efficiency and interfacial instabilities, are calculated in this simulation. Results show that both wettability and pore structures of propped fractures influence significantly the two-component displacement. The results agree qualitatively with the previous results, validating the effectiveness of the present model in predicting binary flows in propped fractures.