Modeling of Fluid Flow in UCRS: Microscale Mechanisms Approach

Abstract

Diffusion forces contribution has been heavily underestimated when modeling fluid flow in porous media specially in unconventional reservoirs with a general agreement that viscous transport is the predominant controller. This work introduces a new comprehensive flow model suitable for tight unconventional reservoirs, including viscous, inertia, and diffusion forces, to account for the transport of fluid in the three scales. The new model addresses1-D linear and radial flow in tight unconventional reservoirs and has been mathematically derived and numerically solved using MATLAB software, and tested against two main cases; a liquid-liquid diffusion case and gas-gas diffusion case. Detailed parametric analysis to examine the effect of the permeability, density and viscosity on the newly derived model has been conducted, and very clear profiles and flow patterns of the main flow parameters were identified. It has been established that, with lower permeability of the porous medium and lower viscosity of the flowing fluid, the diffusion mechanism becomes more predominant in controlling flow velocity. The results of the newly derived equations that includes the diffusion term clearly depict the contribution of diffusion to the flow in the nano scaled pore spaces. The comparison between the suggested equation to existing equations that are used in the field to describe the behavior of the flow in low permeability and low porous medium have been established.

Date of Award	May 2021
Original language	American English