Linking continuum-scale state of wetting to pore-scale contact angles in porous media

Sun, Chenhao; McClure, James E.; Mostaghimi, Peyman; Herring, Anna L.; Shabaninejad, Mehdi; Berg, Steffen; Armstrong, Ryan T.

doi:10.1016/j.jcis.2019.11.105

Cited by 44 publications

(16 citation statements)

References 50 publications

(47 reference statements)

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“…The statement is independent of any force applied and represents a global geometric constraint. For a multiphase system, the Gauss‐Bonnet theorem can be written to relate the total curvature of a three‐dimensional (3‐D) fluid cluster

C

with its surface

M

to its topology as measured by the Euler characteristic

χ

(Chern, ; Sun et al, ):

2 π χ false(M false) = \int_{M} κ_{T} d S + \int_{\partial M} κ_{g} normald C,

where

normald S

is a Riemannian area element along the cluster surface

M

κ_{T} = 1 false/ false(r_{1} r_{2} false)

is the Gaussian curvature along the cluster surface area element.…”

Section: Contact Angle and Deficit Curvaturementioning

confidence: 99%

Probing Effective Wetting in Subsurface Systems

Sun

McClure

Mostaghimi

et al. 2020

Geophysical Research Letters

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Wetting phenomena are of central importance for many natural and technological processes in subsurface geosciences. Surface roughness, chemical heterogeneity, and dynamic effects cause the microscopic contact angle to vary widely in subsurface multiphase systems. These effects must be characterized in a fundamental and transparent way to determine the overall state of wetting. Here, we apply the Gauss‐Bonnet theorem to establish a direct link between the contact angle and bulk fluid topology based on a newly defined term, deficit curvature. The resulting macroscopic measure is able to capture the average effects of complex microscopic variations in contact angle based on intrinsic geometric constraints that are imposed on the curvature of the contact line as a consequence of fluid topology. We show that deficit curvature is able to capture the effects of contact angle hysteresis and describe wetting in multiphase systems where geometrically complex contact lines are present along with surface heterogeneity.

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C

with its surface

M

to its topology as measured by the Euler characteristic

χ

(Chern, ; Sun et al, ):

2 π χ false(M false) = \int_{M} κ_{T} d S + \int_{\partial M} κ_{g} normald C,

where

normald S

is a Riemannian area element along the cluster surface

M

κ_{T} = 1 false/ false(r_{1} r_{2} false)

is the Gaussian curvature along the cluster surface area element.…”

Section: Contact Angle and Deficit Curvaturementioning

confidence: 99%

Probing Effective Wetting in Subsurface Systems

Sun

McClure

Mostaghimi

et al. 2020

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

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“…Most modeling studies have attempted to calibrate multiphase flow in a few rock types based only on the macroscopic experimental data, which, as discussed above, is not reliable [22]. The link between pore-scale wettability and macroscopic properties has been quantified with an assessment of uncertainty [29], which emphasizes the importance of using the correct input wettability.…”

Section: Introductionmentioning

confidence: 99%

Pore-by-pore modeling, analysis, and prediction of two-phase flow in mixed-wet rocks

et al. 2020

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A pore-network model is an upscaled representation of the pore space and fluid displacement, which is used to simulate two-phase flow through porous media. We use the results of pore-scale imaging experiments to calibrate and validate our simulations, and specifically to find the pore-scale distribution of wettability. We employ energy balance to estimate an average, thermodynamic, contact angle in the model, which is used as the initial estimate of contact angle. We then adjust the contact angle of each pore to match the observed fluid configurations in the experiment as a nonlinear inverse problem. The proposed algorithm is implemented on two sets of steady state micro-computed-tomography experiments for water-wet and mixed-wet Bentheimer sandstone. As a result of the optimization, the pore-by-pore error between the model and experiment is decreased to less than that observed between repeat experiments on the same rock sample. After calibration and matching, the model predictions for capillary pressure and relative permeability are in good agreement with the experiments. The proposed algorithm leads to a distribution of contact angle around the thermodynamic contact angle. We show that the contact angle is spatially correlated over around 4 pore lengths, while larger pores tend to be more oil-wet. Using randomly assigned distributions of contact angle in the model results in poor predictions of relative permeability and capillary pressure, particularly for the mixed-wet case.

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“…Although recent developments in μCT tomography have paved the way to study the real fluid distributions at the pore scale, assessing the effect of surface wettability remains challenging. The true surface properties cannot be resolved experimentally, and dynamic effects at the contact line can influence contact angles measured geometrically (AlRatrout et al, 2017; Andrew et al, 2014; McClure et al, 2016; Sun et al, 2020). As a supplementary tool, numerical approaches have been developed to explore the multiphase flow processes at the pore scale (Armstrong et al, 2016; Blunt et al, 2013; Fan et al, 2018; Koroteev et al, 2014; Liu et al, 2016; McClure et al, 2014; Rabbani et al, 2017; Valvatne & Blunt, 2004).…”

Section: Introductionmentioning

confidence: 99%

Influence of Clay Wettability Alteration on Relative Permeability

Fan

McClure

Armstrong

et al. 2020

Geophysical Research Letters

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Understanding the wettability of porous materials is important to model fluid flow in the subsurface. One of the critical factors that influences wetting in real reservoirs is the composition of geologic materials. The wetting properties for clay minerals can have a particularly strong impact on flow and transport. In this work, we analyze the chemical composition of a Mt. Simon sandstone core to resolve the microscopic structure of clay regions and assess how alterations to the local wetting properties influence multiphase transport based on core flooding experiments and relative permeability simulations. We show that whichever fluid has greater affinity toward clay minerals will tend to accumulate within these high surface area regions, leading to dramatic shifts in the relative permeability. This work establishes the essential importance of the mineral composition and associated wetting properties in the modeling of flow and transport in reservoir-scale systems. Plain Language Summary Surface interactions between fluid and solid materials have important consequences for underground fluid flow. Wettability refers to the relative preference for one fluid to coat the solid surface when multiple fluids are present. Exposure to different fluids can dramatically alter the wettability for mineral surfaces in geological systems, which can have a significant effect on multiphase flow in geological reservoirs. We show that alteration of the wetting properties for clay regions can dramatically alter the behavior for water and CO 2 to flow through reservoir rocks. The underlying causes for these effects are understood by examining microscopic fluid configurations obtained based on the composition of geologic materials. A deeper comprehension of CO 2 flow and transport behavior in a reservoir rock with high mineralogical heterogeneities will aid the CO 2 storage capacity prediction and reduce CO 2 leakage potential.

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Linking continuum-scale state of wetting to pore-scale contact angles in porous media

Cited by 44 publications

References 50 publications

Probing Effective Wetting in Subsurface Systems

Probing Effective Wetting in Subsurface Systems

Pore-by-pore modeling, analysis, and prediction of two-phase flow in mixed-wet rocks

Influence of Clay Wettability Alteration on Relative Permeability

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