Transient analysis of advancing contact angle measurements on polished rock surfaces

C. H. Gates; E. Perfect; B. S. Lokitz; J. W. Brabazon; L. D. McKay; J. S. Tyner

doi:10.1016/j.advwatres.2018.03.017

Transient analysis of advancing contact angle measurements on polished rock surfaces

C. H. Gates, E. Perfect, B. S. Lokitz, J. W. Brabazon, L. D. McKay, J. S. Tyner

Center for Nanophase Matls Sciences

Research output: Contribution to journal › Article › peer-review

12 Scopus citations

Abstract

Contact angle measurements for gas-liquid-rock systems are important for modeling multi-phase flow and transport in the subsurface. These data are needed in applications such as the extraction of oil and gas resources, geologic sequestration of carbon dioxide, contaminant fate and transport, and aquifer recharge through the vadose zone. Contact angles are frequently measured with the sessile drop method. Previous research has largely ignored the dynamic behavior of sessile droplets on geologic materials. This study investigates the dynamic behavior of sessile water droplets on prepared rock surfaces in the presence of air. Droplet diameter and advancing contact angle were determined at 0.5 s intervals for ∼ 90 s on flat polished disks of Burlington limestone, Crossville sandstone, Mancos shale, Sierra White granite, Vermilion Bay granite, and Westerly granite using a Krüss DSA 30 Drop Shape Analyzer. The droplet diameter and advancing contact angle data sets were nonlinearly regressed against time using two different two-parameter models. The median coefficients of determination for the fits were 0.85 and 0.96, respectively. The resulting parameter estimates were used to compute the apparent equilibrium contact angle, θ_e, for each disk following droplet diameter stabilization. Estimates of θ_e ranged from 37.2° for Mancos shale to 75.6° for Burlington limestone. Analysis of variance indicated statistically significant differences in θ_e between the rock types at the 95% confidence level. The variability of θ_e on the polished rock surfaces, as quantified by the coefficient of variation (CV) for θ_e, varied between ∼ 3 and ∼ 9%; there were no significant differences in CV between the rock types. Neutron radiography indicated changes droplet morphology over time were due to the spontaneous imbibition of water into the rock matrix. The transient analysis employed in this study permits a more meaningful estimate of the equilibrium contact angle for rocks than taking the initial value or averaging over time as is frequently done.

Original language	English
Pages (from-to)	142-149
Number of pages	8
Journal	Advances in Water Resources
Volume	119
DOIs	https://doi.org/10.1016/j.advwatres.2018.03.017
State	Published - Sep 2018

Funding

This research was sponsored by the Army Research Laboratory and was accomplished under Grant Number W911NF-16-1-0043 . Portions of this research used resources at the High Flux Isotope Reactor and Center for Nanophase Materials Sciences, which are DOE Office of Science User Facilities operated by Oak Ridge National Laboratory. E. Perfect acknowledges support from the Tom Cronin and Helen Sestak Faculty Achievement award. The solid-phase density, dry bulk density, porosity, and capillary pressure – saturation data were collected by A.D. Vial.

Funders	Funder number
Tom Cronin and Helen Sestak Faculty Achievement
Army Research Laboratory	W911NF-16-1-0043

Keywords

Air-water surface tension
Dynamic contact angle
Equilibrium contact angle
Hydrophilicity
Neutron radiography
Spontaneous imbibition

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10.1016/j.advwatres.2018.03.017

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title = "Transient analysis of advancing contact angle measurements on polished rock surfaces",

abstract = "Contact angle measurements for gas-liquid-rock systems are important for modeling multi-phase flow and transport in the subsurface. These data are needed in applications such as the extraction of oil and gas resources, geologic sequestration of carbon dioxide, contaminant fate and transport, and aquifer recharge through the vadose zone. Contact angles are frequently measured with the sessile drop method. Previous research has largely ignored the dynamic behavior of sessile droplets on geologic materials. This study investigates the dynamic behavior of sessile water droplets on prepared rock surfaces in the presence of air. Droplet diameter and advancing contact angle were determined at 0.5 s intervals for ∼ 90 s on flat polished disks of Burlington limestone, Crossville sandstone, Mancos shale, Sierra White granite, Vermilion Bay granite, and Westerly granite using a Kr{\"u}ss DSA 30 Drop Shape Analyzer. The droplet diameter and advancing contact angle data sets were nonlinearly regressed against time using two different two-parameter models. The median coefficients of determination for the fits were 0.85 and 0.96, respectively. The resulting parameter estimates were used to compute the apparent equilibrium contact angle, θe, for each disk following droplet diameter stabilization. Estimates of θe ranged from 37.2° for Mancos shale to 75.6° for Burlington limestone. Analysis of variance indicated statistically significant differences in θe between the rock types at the 95% confidence level. The variability of θe on the polished rock surfaces, as quantified by the coefficient of variation (CV) for θe, varied between ∼ 3 and ∼ 9%; there were no significant differences in CV between the rock types. Neutron radiography indicated changes droplet morphology over time were due to the spontaneous imbibition of water into the rock matrix. The transient analysis employed in this study permits a more meaningful estimate of the equilibrium contact angle for rocks than taking the initial value or averaging over time as is frequently done.",

keywords = "Air-water surface tension, Dynamic contact angle, Equilibrium contact angle, Hydrophilicity, Neutron radiography, Spontaneous imbibition",

author = "Gates, {C. H.} and E. Perfect and Lokitz, {B. S.} and Brabazon, {J. W.} and McKay, {L. D.} and Tyner, {J. S.}",

note = "Publisher Copyright: {\textcopyright} 2018 Elsevier Ltd",

year = "2018",

month = sep,

doi = "10.1016/j.advwatres.2018.03.017",

language = "English",

volume = "119",

pages = "142--149",

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TY - JOUR

T1 - Transient analysis of advancing contact angle measurements on polished rock surfaces

AU - Gates, C. H.

AU - Perfect, E.

AU - Lokitz, B. S.

AU - Brabazon, J. W.

AU - McKay, L. D.

AU - Tyner, J. S.

PY - 2018/9

Y1 - 2018/9

N2 - Contact angle measurements for gas-liquid-rock systems are important for modeling multi-phase flow and transport in the subsurface. These data are needed in applications such as the extraction of oil and gas resources, geologic sequestration of carbon dioxide, contaminant fate and transport, and aquifer recharge through the vadose zone. Contact angles are frequently measured with the sessile drop method. Previous research has largely ignored the dynamic behavior of sessile droplets on geologic materials. This study investigates the dynamic behavior of sessile water droplets on prepared rock surfaces in the presence of air. Droplet diameter and advancing contact angle were determined at 0.5 s intervals for ∼ 90 s on flat polished disks of Burlington limestone, Crossville sandstone, Mancos shale, Sierra White granite, Vermilion Bay granite, and Westerly granite using a Krüss DSA 30 Drop Shape Analyzer. The droplet diameter and advancing contact angle data sets were nonlinearly regressed against time using two different two-parameter models. The median coefficients of determination for the fits were 0.85 and 0.96, respectively. The resulting parameter estimates were used to compute the apparent equilibrium contact angle, θe, for each disk following droplet diameter stabilization. Estimates of θe ranged from 37.2° for Mancos shale to 75.6° for Burlington limestone. Analysis of variance indicated statistically significant differences in θe between the rock types at the 95% confidence level. The variability of θe on the polished rock surfaces, as quantified by the coefficient of variation (CV) for θe, varied between ∼ 3 and ∼ 9%; there were no significant differences in CV between the rock types. Neutron radiography indicated changes droplet morphology over time were due to the spontaneous imbibition of water into the rock matrix. The transient analysis employed in this study permits a more meaningful estimate of the equilibrium contact angle for rocks than taking the initial value or averaging over time as is frequently done.

AB - Contact angle measurements for gas-liquid-rock systems are important for modeling multi-phase flow and transport in the subsurface. These data are needed in applications such as the extraction of oil and gas resources, geologic sequestration of carbon dioxide, contaminant fate and transport, and aquifer recharge through the vadose zone. Contact angles are frequently measured with the sessile drop method. Previous research has largely ignored the dynamic behavior of sessile droplets on geologic materials. This study investigates the dynamic behavior of sessile water droplets on prepared rock surfaces in the presence of air. Droplet diameter and advancing contact angle were determined at 0.5 s intervals for ∼ 90 s on flat polished disks of Burlington limestone, Crossville sandstone, Mancos shale, Sierra White granite, Vermilion Bay granite, and Westerly granite using a Krüss DSA 30 Drop Shape Analyzer. The droplet diameter and advancing contact angle data sets were nonlinearly regressed against time using two different two-parameter models. The median coefficients of determination for the fits were 0.85 and 0.96, respectively. The resulting parameter estimates were used to compute the apparent equilibrium contact angle, θe, for each disk following droplet diameter stabilization. Estimates of θe ranged from 37.2° for Mancos shale to 75.6° for Burlington limestone. Analysis of variance indicated statistically significant differences in θe between the rock types at the 95% confidence level. The variability of θe on the polished rock surfaces, as quantified by the coefficient of variation (CV) for θe, varied between ∼ 3 and ∼ 9%; there were no significant differences in CV between the rock types. Neutron radiography indicated changes droplet morphology over time were due to the spontaneous imbibition of water into the rock matrix. The transient analysis employed in this study permits a more meaningful estimate of the equilibrium contact angle for rocks than taking the initial value or averaging over time as is frequently done.

KW - Air-water surface tension

KW - Dynamic contact angle

KW - Equilibrium contact angle

KW - Hydrophilicity

KW - Neutron radiography

KW - Spontaneous imbibition

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DO - 10.1016/j.advwatres.2018.03.017

M3 - Article

AN - SCOPUS:85050268688

SN - 0309-1708

VL - 119

SP - 142

EP - 149

JO - Advances in Water Resources

JF - Advances in Water Resources

ER -

Transient analysis of advancing contact angle measurements on polished rock surfaces

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Keywords

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