Preferential imbibition in a dual-permeability pore network

A deep understanding of two-phase displacement in porous media with permeability contrast is essential for the design and optimisation of enhanced oil recovery processes. In this paper, we investigate the forced imbibition behaviour in two dual-permeability geometries that are of equal permeability contrast. First, a mathematical model is developed for the imbibition in a pore doublet, which shows that the imbibition dynamics can be fully described by the viscosity ratio curve on which the breakthrough simultaneously occurs in both permeability zones is found to match well with that from the pore doublet and it is the optimal condition for maximising the imbibition efficiency in the entire pore network.