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Title: Flow regimes during immiscible displacement

Abstract

Fractional ow of immiscible phases occurs at the pore scale where grain surfaces and phases interfaces obstruct phase mobility. However, the larger scale behavior is described by a saturation-dependent phenomenological relationship called relative permeability. As a consequence, pore-scale parameters, such as phase topology and/ or geometry, and details of the flow regime cannot be directly related to Darcy-scale flow parameters. It is well understood that relative permeability is not a unique relationship of wetting-phase saturation and rather depends on the experimental conditions at which it is measured. Herein we use fast X-ray microcomputed tomography to image pore-scale phase arrangements during fractional flow and then forward simulate the flow regimes using the lattice-Boltzmann method to better understand the underlying pore-scale flow regimes and their influence on Darcy-scale parameters. We find that relative permeability is highly dependent on capillary number and that the Corey model fits the observed trends. At the pore scale, while phase topologies are continuously changing on the scale of individual pores, the Euler characteristic of the nonwetting phase (NWP) averaged over a sufficiently large field of view can describe the bulk topological characteristics; the Euler characteristic decreases with increasing capillary number resulting in an increase in relative permeability.more » Lastly, we quantify the fraction of NWP that flows through disconnected ganglion dynamics and demonstrate that this can be a significant fraction of the NWP flux for intermediate wetting-phase saturation. Furthermore, rate dependencies occur in our homogenous sample (without capillary end effect) and the underlying cause is attributed to ganglion flow that can significantly influence phase topology during the fractional flow of immiscible phases.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [6]
  1. Univ. of New South Wales, Sydney (Australia)
  2. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Imperial College, London (United Kingdom); Shell Global Solutions International (The Netherlands)
  5. Helmholtz Centre for Environmental Research - UFZ (Germany)
  6. Shell Global Solutions International (The Netherlands)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org.:
USDOE
OSTI Identifier:
1344294
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Petrophysics
Additional Journal Information:
Journal Volume: 58; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Citation Formats

Armstrong, Ryan T., Mcclure, James, Berrill, Mark A., Rucker, Maja, Schluter, S, and Berg, Steffen. Flow regimes during immiscible displacement. United States: N. p., 2017. Web.
Armstrong, Ryan T., Mcclure, James, Berrill, Mark A., Rucker, Maja, Schluter, S, & Berg, Steffen. Flow regimes during immiscible displacement. United States.
Armstrong, Ryan T., Mcclure, James, Berrill, Mark A., Rucker, Maja, Schluter, S, and Berg, Steffen. Wed . "Flow regimes during immiscible displacement". United States. doi:. https://www.osti.gov/servlets/purl/1344294.
@article{osti_1344294,
title = {Flow regimes during immiscible displacement},
author = {Armstrong, Ryan T. and Mcclure, James and Berrill, Mark A. and Rucker, Maja and Schluter, S and Berg, Steffen},
abstractNote = {Fractional ow of immiscible phases occurs at the pore scale where grain surfaces and phases interfaces obstruct phase mobility. However, the larger scale behavior is described by a saturation-dependent phenomenological relationship called relative permeability. As a consequence, pore-scale parameters, such as phase topology and/ or geometry, and details of the flow regime cannot be directly related to Darcy-scale flow parameters. It is well understood that relative permeability is not a unique relationship of wetting-phase saturation and rather depends on the experimental conditions at which it is measured. Herein we use fast X-ray microcomputed tomography to image pore-scale phase arrangements during fractional flow and then forward simulate the flow regimes using the lattice-Boltzmann method to better understand the underlying pore-scale flow regimes and their influence on Darcy-scale parameters. We find that relative permeability is highly dependent on capillary number and that the Corey model fits the observed trends. At the pore scale, while phase topologies are continuously changing on the scale of individual pores, the Euler characteristic of the nonwetting phase (NWP) averaged over a sufficiently large field of view can describe the bulk topological characteristics; the Euler characteristic decreases with increasing capillary number resulting in an increase in relative permeability. Lastly, we quantify the fraction of NWP that flows through disconnected ganglion dynamics and demonstrate that this can be a significant fraction of the NWP flux for intermediate wetting-phase saturation. Furthermore, rate dependencies occur in our homogenous sample (without capillary end effect) and the underlying cause is attributed to ganglion flow that can significantly influence phase topology during the fractional flow of immiscible phases.},
doi = {},
journal = {Petrophysics},
number = 1,
volume = 58,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2017},
month = {Wed Feb 01 00:00:00 EST 2017}
}

Journal Article:
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  • The flow in the region of an interface during an immiscible displacement process is of particular interest in systems where interfacial properties dominate, i.e., systems of capillary dimensions. An example is discussed as the production of crude oil from naturally occurring reservoirs. There is a basic lack of knowledge of the mechanisms by which the liquid/fluid/solid 3-phase line moves in immiscible displacement. This work summarizes the results of experiments designed to provide a qualitative description of the flow in the region of an interface during immiscible displacement, which highlight the inadequacies of present hydrodynamic analyses. In all cases, the flowsmore » observed some distance from the interfacial region were qualitatively the same. Results suggest that the very presence of a well-defined 3-phase contact line was not a dominant factor in determination of the flow regime.« less
  • A new analytical approach has been developed for the prediction of oil recovery and saturation distribution of an unstable displacement of oil by an immiscible fluid in the absence of capillary and gravity forces. Darcy's law is extended to two-phase flow by introducing relative flow areas available to each phase and a saturation-dependent viscosity to characterize the flow behavior of the mixture at each point in the bed. This enables prediction of a saturation profile, breakthrough recovery, and pressure drop of the mixed zone. The approach was also generalized for polymer flooding. The expression for the breakthrough recovery of themore » polymer flood reflected an effect of the power-law exponent, n. Lower values of n, which corresponded to the more non-Newtonian behavior of the polymer solution, resulted in lower expected recovery efficiency. Several linear displacements were conducted to check the analytical model. Good agreement was obtained between predicted breakthrough recovery and the experimental data. Similar agreement was obtained with available literature data for displacement tests in systems which are significantly different from that used in this work.« less
  • A model is formulated in order to study the transient behavior of oil ganglion populations during immiscible displacement in oil recovery processes. The model is composed of 3 components: a suitable model for granular porous media; a stochastic simulation method capable of predicting the expected fate (mobilization, breakup, stranding) of solitary oil ganglia moving through granular porous media; and 2 coupled ganglion population balance equations, one applying to moving ganglia and the other to stranded ones. The porous medium model consists of a regular network of randomly sized unit cells of the constricted tube type. 32 references.
  • Strong interest in the dynamic behavior of a population of non-wetting ganglia undergoing immiscible displacement has arisen because this problem is central to the understanding of oil-bank formation during enhanced oil recovery by chemical flooding. The same problem arises in the analysis of the relative permeabilities to any pair of wetting and non-wetting phases, when the saturation of the wetting phase exceeds approx. 0.60. Saturation of a phase is defined as the fraction of the void space that is occupied by that phase. Many drainage or imbibition phenomena fall into this category. This work concentrates on the case where themore » non-wetting phase is oleic (oil-based), the wetting phase is aqueous, and the objective is enhanced oil recovery. Discussions include theoretical modeling of the porous medium; mobilization, fissioning, and stranding of a solitary oil ganglion; and dynamics of oil-ganglion populations. 39 references.« less