Effects of Capillary Heterogeneities on Spontaneous Imbibition

Abstract

Abstract This paper presents numerical studies of spontaneous imbibition phenomenon in a heterogeneous matrix block of porous medium in one and two dimensional systems. Heterogeneous distributions of permeability as well as wettability that could affect spontaneous imbibition are considered. Deterministic and stochastic heterogeneity profiles with correlated and uncorrelated fields for permeability and wettability distributions are considered. Both countercurrent with gravity forces and simultaneous cocurrent and countercurrent flows are studied. Numerical model is tested with an experimental study with input measured parameters. Deterministic profiles for permeability have strong effects on saturation and recovery curves for countercurrent imbibition in one and two dimensional systems. Uncorrelated permeability fields with log-normal and fBm statistics yield strong responses in saturation with high amplitudes. Correlated fields give smooth responses in saturation. However, recovery curves are affected considerably by correlated fields depending on realizations. Heterogeneous forms of wettability have strong influence on responses in saturation and weak influence on responses in recovery curves compared to responses in heterogeneous permeability fields. Interaction of gravity with heterogeneity is also considered for countercurrent flow in one dimensional systems. Some examples of heterogeneous forms of permeability and wettability are also considered in two dimensional systems.