Experimental modelling of hydraulic parameters for fluid flow in stratified porous media

Abstract

From works in in-situ seepage through dams and laboratory experiments using Layered Heterogeneous Porous Media (LHPM), it has been noted that a refraction-like phenomenon, such as that experienced in light, affects fluids’ flowlines when crossing the contact interface of layers characterised by different porosity viz-a-viz permeability. This concept has many applications in fluid dynamics, such as the dispersion process in stratified media. Currently, no study exists that models and analyses the relationship between the porosities of two layers in contact and the resulting flowline refraction using validated LHPM data. Hence, this work aims to establish a relationship between the porosity ratio Φr of stratified media made up of two layers and the refraction angle θmax of the maximum volume flux qmax. Volume flux data from the flow of a single-phase fluid through five LHPMs with Φr ranging from 0.8325 to 0.9524 were used in the modelling. The flow was oriented from the lower to the higher porosity vis-à-vis permeability layer. It was found that θmax which is also the refraction angle of the peak solute plume flux, refracts away from the normal as Φr reduces. This indicates an increase in the dilution rate vis-à-vis spread of plumes with the reduction in homogeneity between the two layers. Also, θmax does not correlate with the stratification inclination α, but the qmax which is also the peak solute plume flux correlates with α. Furthermore, an efficient model, which is the best-unbiased estimator, with R2=0.99 was derived. Findings from this work can help better understand solute plume dispersion and the general fluid flow dynamics in stratified media such as capillary barrier effect covers for pollution control and hydrocarbon reservoirs.