A coarsescale compositional model

Authors: Alireza Iranshahr Yuguang Chen Denis V Voskov

Publish Date: 2014/06/25

Volume: 18, Issue: 5, Pages: 797-815

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Abstract

In subsurface flow modeling compositional simulation is often required to model complex recovery processes such as gas/CO 2 injection However compositional simulation on finescale geological models is still computationally expensive and even prohibitive Most existing upscaling techniques focus on blackoil models In this paper we present a general framework to upscale twophase multicomponent flow in compositional simulation Unlike previous studies our approach explicitly considers the upscaling of flow and thermodynamics In the flow part we introduce a new set of upscaled flow functions that account for the effects of compressibility This is often ignored in the upscaling of blackoil models In the upscaling of thermodynamics we show that the oil and gas phases within a coarse block are not at chemical equilibrium This nonequilibrium behavior is modeled by upscaled thermodynamic functions which measure the difference between component fugacities among the oil and gas phases We apply the approach to various gas injection problems with different compositional features permeability heterogeneity and coarsening ratios It is shown that the proposed method accurately reproduces the averaged finescale solutions such as component overall compositions gas saturation and density solutions in the compositional flow

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