A Multicomponent Dual-Porosity Model for Gas Reservoir Flow With Adsorption Behaviour

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis study presents a modified dual-porosity model for multispecies gas flow with adsorption behaviour, which is formulated from an exact formal solution of a linear multicomponent gas diffusion process within a porous matrix block. Therefore, the coupling effects of mutual-diffusion are included in the representation. This new respresentation, in its first order form, exhibits to be a simple algebraic expression that is of an equivalent computational efficiency in comparison with the traditional Warren and Root. Yet, the mutual-diffusion effect is not present in the latter one.A numerical algorithm is also developed for this model when the full form of it, which is of an integral form with history-dependency, is incorporated into a set of multi-phase and multi-species flow equations. A numerical example with the proposed model for a two-phase and three gas-species flow is performed in light of a parametric study, demonstrating that multi-component gas species interactions have significant influences on the flow profile. For instance, even if the offdiagonal diffusion coefficients are smaller by one order of magnitude in comparison to their diagonal counterparts, the resultant effect on model predictions can still be 10~35%. Ignoring the diffusional interactions between the gas species, as is done with the Warren-Root, will introduce considerable deviations.