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Title: Evaluation of two-phase relative permeability and capillary pressure relations for unstable displacements in a pore network

Abstract

A series of displacement experiments was conducted using five wetting-nonwetting immiscible fluid pairs in a homogenous and uniform pore network. The micromodel was initially saturated with either polyethylene glycol 200 (PEG) or water as a wetting fluid, which was subsequently displaced by a nonwetting fluid (dodecane, hexadecane, or mineral oil) at different flow rates. The experiments were designed to allow determinations of nonwetting fluid relative permeabilities ( ), fluid saturations ( ), and capillary pressure heads ( ). In the displacements, nonwetting fluid saturations increased with increasing flow rates for all five fluid pairs, and viscous fingering, capillary fingering, and stable displacement were observed. Viscous fingering occurred when PEG was displaced by either dodecane or hexadecane. For the water displacements, capillary fingers were observed at low capillary numbers. Due to unstable fingering phenomena, values for the PEG displacements were smaller than for the water displacements. A fitting exercise using the Brooks-Corey (1964) relationship showed that the fitted entry pressure heads are reasonably close to the computed entry pressure head. The fitted pore geometry factor, S n values for the displacements are considerably lower than what is expected for displacements in homogeneous, highly uniform, porous systems, demonstrating the impact of unstablemore » displacement on the apparent value of S n. It was shown that a continuum-based multiphase model could be used to predict the average behavior for wetting fluid drainage in a pore network as long as independently fitted - and - relations are used. The use of a coupled approach through the Brooks-Corey pore geometry factor underpredicts observed values.« less

Authors:
 [1];  [1];  [1];  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1057815
Report Number(s):
PNNL-SA-85825
Journal ID: ISSN 1539-1663; 39094
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Vadose Zone Journal
Additional Journal Information:
Journal Volume: 11; Journal Issue: 4; Journal ID: ISSN 1539-1663
Publisher:
Soil Science Society of America
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; micromodels; pore networks; multifluid displacement; Environmental Molecular Sciences Laboratory

Citation Formats

Dehoff, Karl J., Oostrom, Martinus, Zhang, Changyong, and Grate, Jay W. Evaluation of two-phase relative permeability and capillary pressure relations for unstable displacements in a pore network. United States: N. p., 2012. Web. doi:10.2136/vzj2012.0024.
Dehoff, Karl J., Oostrom, Martinus, Zhang, Changyong, & Grate, Jay W. Evaluation of two-phase relative permeability and capillary pressure relations for unstable displacements in a pore network. United States. doi:10.2136/vzj2012.0024.
Dehoff, Karl J., Oostrom, Martinus, Zhang, Changyong, and Grate, Jay W. Mon . "Evaluation of two-phase relative permeability and capillary pressure relations for unstable displacements in a pore network". United States. doi:10.2136/vzj2012.0024.
@article{osti_1057815,
title = {Evaluation of two-phase relative permeability and capillary pressure relations for unstable displacements in a pore network},
author = {Dehoff, Karl J. and Oostrom, Martinus and Zhang, Changyong and Grate, Jay W.},
abstractNote = {A series of displacement experiments was conducted using five wetting-nonwetting immiscible fluid pairs in a homogenous and uniform pore network. The micromodel was initially saturated with either polyethylene glycol 200 (PEG) or water as a wetting fluid, which was subsequently displaced by a nonwetting fluid (dodecane, hexadecane, or mineral oil) at different flow rates. The experiments were designed to allow determinations of nonwetting fluid relative permeabilities ( ), fluid saturations ( ), and capillary pressure heads ( ). In the displacements, nonwetting fluid saturations increased with increasing flow rates for all five fluid pairs, and viscous fingering, capillary fingering, and stable displacement were observed. Viscous fingering occurred when PEG was displaced by either dodecane or hexadecane. For the water displacements, capillary fingers were observed at low capillary numbers. Due to unstable fingering phenomena, values for the PEG displacements were smaller than for the water displacements. A fitting exercise using the Brooks-Corey (1964) relationship showed that the fitted entry pressure heads are reasonably close to the computed entry pressure head. The fitted pore geometry factor, Sn values for the displacements are considerably lower than what is expected for displacements in homogeneous, highly uniform, porous systems, demonstrating the impact of unstable displacement on the apparent value of Sn. It was shown that a continuum-based multiphase model could be used to predict the average behavior for wetting fluid drainage in a pore network as long as independently fitted - and - relations are used. The use of a coupled approach through the Brooks-Corey pore geometry factor underpredicts observed values.},
doi = {10.2136/vzj2012.0024},
journal = {Vadose Zone Journal},
issn = {1539-1663},
number = 4,
volume = 11,
place = {United States},
year = {2012},
month = {10}
}