Line Tension-Based Modification of Young's Equation for Rock-Oil-Brine Systems

2009 ◽  
Vol 12 (05) ◽  
pp. 702-712 ◽  
Author(s):  
Dayanand Saini ◽  
Dandina N. Rao

Summary The two-century-old Young's equation has been widely used in petroleum engineering to depict the reservoir wettability in terms of contact angle, which is a function of surface free energies of the system. For solid/liquid/vapor (S/L/V) systems, Young's equation has been modified in the recent literature to include a line-tension term. This modification was sought to accommodate the imbalance of intermolecular forces experienced by the three-phase confluence zone. Also, Young's equation does not account for the vertical component of liquid/vapor surface tension. The present study aims to experimentally investigate the applicability of the line-tension-based modification of Young's equation to solid/liquid/liquid (rock/oil/brine) (S/L/L) systems of interest to the petroleum industry. Both the ambient- and reservoir-condition optical cells were used, with stock-tank and live oil, respectively, to determine the drop-size dependence of dynamic contact angle subtended by the oil/brine interface with the rock surface. The experimental data were correlated with the modified Young's equation to determine the magnitude of line tension for different rock/oil/brine systems. To the best of our knowledge, this is the first attempt to apply the modified Young's equation to rock/oil/brine systems and to measure line tension for a rock/live-crude-oil/brine system at reservoir conditions of pressure and temperature. The measured line tension for S/L/L systems, while being positive and of the same order of magnitude as in S/L/V systems, correlates well with the water-advancing contact angle and the adhesion number, a ratio of adhesion force to capillary force. This experimental study indicates that the extent of deviation from Young's equation exhibited by rock/oil/brine systems may be directly related to the rock/oil adhesion interaction. This study reinforces the need to include the rock/oil adhesion force in our consideration of rock/fluid interactions, wettability, and their impact on enhanced-oil-recovery (EOR)/improved-oil-recovery (IOR) processes.

2016 ◽  
Vol 6 (1) ◽  
pp. 96
Author(s):  
Ai-Jun Hu ◽  
Bao-Zhan Lv

<p class="1Body">Wetting of a spherical nanodroplet in smooth and homogeneous cylinder surface rotated by quadratic curve was studied by methods of thermodynamics. The solid-liquid-vapor system was separated into six parts using Gibbs method of dividing surface. The system free energy was calculated. A generalized Young equation for the equilibrium contact angle is proposed taking the line tension effects into consideration. On the basis of some assumptions, this generalized Young equation is the same as the classical Young’s equation.</p>


2021 ◽  
Author(s):  
Xu-Guang Song ◽  
Ming-Wei Zhao ◽  
Cai-Li Dai ◽  
Xin-Ke Wang ◽  
Wen-Jiao Lv

AbstractThe ultra-low permeability reservoir is regarded as an important energy source for oil and gas resource development and is attracting more and more attention. In this work, the active silica nanofluids were prepared by modified active silica nanoparticles and surfactant BSSB-12. The dispersion stability tests showed that the hydraulic radius of nanofluids was 58.59 nm and the zeta potential was − 48.39 mV. The active nanofluids can simultaneously regulate liquid–liquid interface and solid–liquid interface. The nanofluids can reduce the oil/water interfacial tension (IFT) from 23.5 to 6.7 mN/m, and the oil/water/solid contact angle was altered from 42° to 145°. The spontaneous imbibition tests showed that the oil recovery of 0.1 wt% active nanofluids was 20.5% and 8.5% higher than that of 3 wt% NaCl solution and 0.1 wt% BSSB-12 solution. Finally, the effects of nanofluids on dynamic contact angle, dynamic interfacial tension and moduli were studied from the adsorption behavior of nanofluids at solid–liquid and liquid–liquid interface. The oil detaching and transporting are completed by synergistic effect of wettability alteration and interfacial tension reduction. The findings of this study can help in better understanding of active nanofluids for EOR in ultra-low permeability reservoirs.


Author(s):  
C. A. Ward

A method for determining the surface tension of solid-fluid interfaces has been proposed. For a given temperature and fluid-solid combination, these surface tensions are expressed in terms of material properties that can be determined by measuring the amount of vapor adsorbed on the solid surface as a function of xV, the ratio of the vapor-phase pressure to the saturation-vapor pressure. The thermodynamic concept of pressure is shown to be in conflict with that of continuum mechanics, but is supported experimentally. This approach leads to the prediction that the contact angle, θ, can only exist in a narrow pressure range and that in this pressure range, the solid-vapor surface tension is constant and equal to the surface tension of the liquid-vapor interface, γLV. The surface tension of the solid-liquid interface, γSL, may be expressed in terms of measurable properties, γLV and θ: γSL = γLV(1 − cosθ). The value of θ is predicted to depend on both the pressure in the liquid at the three-phase, line x3L, and the three-phase line curvature, Ccl. We examine these predictions using sessile water droplets on a polished Cu surface, maintained in a closed, constant volume, isothermal container. The value of θ is found to depend on the adsorption at the solid-liquid interface, nSL = nSL(x3L,Ccl). The predicted value of θ is compared with that measured, and found to be in close agreement, but no effect of line tension is found.


1999 ◽  
Vol 13 (27) ◽  
pp. 3255-3259 ◽  
Author(s):  
HARVEY DOBBS

We derive the modified Young's equation for the contact angle of a fluid droplet on a rigid substrate using an interface displacement model and identify the line tension with the excess free energy per unit length calculated previously for a straight three-phase contact line.


2019 ◽  
Vol 11 (2) ◽  
pp. 127
Author(s):  
Mumuni Amadu ◽  
Adango Miadonye

The solid-liquid interfacial tension is a fundamental parameter in areas of wettability pertaining to adhesive bonds and petroleum engineering practice. In wettability issues related to surface functionalized polymeric materials design to achieve specific adhesive properties, the solid-liquid interfacial tension can be pH dependent due to amphoteric behavior. In this paper, we have used the theory of pH dependent surface charging and the 2-pk model as well as the site binding model of the electric double layer theory to derive a pH dependent solid-liquid interfacial tension equation. Following the fundamental relationship between solid-liquid interfacial tension and contact angle in light of Young&rsquo;s equation, we have extended the theoretical basis of the derivation. Consequently, we have also derived a pH dependent cosine of the thermodynamic contact angle. Both equations give satisfactory explanations for observed experimental data available in the literature.


1996 ◽  
Vol 44 (4) ◽  
pp. 1657-1663 ◽  
Author(s):  
Yixiong Liu ◽  
R.M. German

A cleavage technique has been used to measure solid/fluid interfacial energies, and to study directly the effect of various media on these energies. Solid/vapour and solid/liquid interfacial energies were measured by cleaving mica specimens first in an atmosphere of vapour and then in the corresponding liquid. In this way we have a direct means of checking the validity of Young’s equation. Results obtained with water, as representative of a polar medium, and hexane, as representative of a non-polar medium show that Young’s equation holds for systems with zero contact angle. The effect of the humidity of the surrounding atmosphere on the cleavage of mica was also investigated. Water vapour was found to produce a marked reduction in the cleavage energy. In another set of experiments the cleavage technique was used to determine the work done in separating mica surfaces covered with an adsorbed monomolecular layer of fatty acid. The results yield a value of 37 erg/cm 2 for the surface energy of a lauric acid monolayer on mica.


Author(s):  
Dandina N. Rao ◽  
Hussain H. Radwani

The engineering applications of spreading and adhesion phenomena involving fluids on solids are numerous. The adhesive and spreading interactions at the solid-fluid interfaces are well characterized by dynamic contact angles. This study reports on the results of an experimental investigation into the effect of solid surface roughness on dynamic contact angles in solid-liquid-liquid (S-L-L) systems. The experiment involved the use of Wilhelmy Plate apparatus to measure adhesion tension (which is the product of interfacial tension and cosine of the contact angle between the liquid-liquid interface and the solid surface), the DuNuoy tensiometer to measure the liquid-liquid interfacial tension, and a profilometer to characterize the roughness of the solid surfaces used. The components of the solid-liquid-liquid systems studied consisted of: (i) smooth glass, roughened quartz and an actual rock surface for the solid phase, (ii) normal-hexane and deionized water as the two immiscible liquid phases. The dynamic contact angles (advancing and receding angles) of the three-phase (rock-oil-water) system provide essential information about the wettability of petroleum resrvoirs. The wettability of a reservoir is an important parameter that affects oil recovery in primary, secondary, and enhanced recovery operations [1]. Contact angle measurements on smooth surfaces are generally used to characterize reservoir wettability. However pore surfaces within reservoir rocks are essentially rough and hence it is important to determine the effect of such roughness on measured contact angles. There is very little information in the open literature on the effect of surface roughness on dynamic contact angles in S-L-L systems. In the present work, four levels of roughness of solid surfaces of similar mineralogy (quartz and glass) were tested in hexane-deionized water fluid pair. The advancing and receding contact angles measured at ambient conditions were analyzed for wettability effects. It was found that as surface roughness increased, the dynamic contact angles also increased. The wettability of the rock-oil-water system shifted from weakly water-wet for the smooth glass to intermediate-wet for the roughened surface. The general trends observed in our study were found to be in good agreement with other published results. However, the generally held notion of increasing contact angle hysteresis with increasing roughness appears to be incorrect in solid-liquid-liquid systems.


2016 ◽  
Vol 30 (07) ◽  
pp. 1650078
Author(s):  
Ai-Jun Hu ◽  
Bao-Zhan Lv ◽  
Xiao-Song Wang ◽  
Long Zhou

Wetting of droplets on homogeneous and spherical concave rough surfaces is investigated based on thermodynamics. In this study, neglecting the droplet gravity and the thickness of the precursor film of the liquid–vapor interface, the three-phase system is divided into six parts using Gibbs concept of dividing surface. The system Helmholtz free energy is established based on thermodynamics. Supposing the temperature and chemical potential to be constant, a new generalized Young’s equation of the equilibrium contact angle for a spherical droplet on a spherical concave rough surfaces is obtained including the line tension effects. Under certain conditions, this generalized Young’s equation is the same as the Rusanov’s equation.


Author(s):  
H. Ghasemi ◽  
C. A. Ward

A method has been recently proposed for determining the surface tension of solid-vapor interfaces. The proposed method was used in conjunction with Gibbsian thermodynamics to investigate both analytically and experimentally the possible role of line tension in determining the contact angle of sessile-water-droplets. After forming a sessile-water-droplet in a closed system, its contact angle was determined by measuring the curvature of three-phase contact line and the height of the axisymmetric droplet on its centerline. The total number of the moles in the closed system was determined from the minimum in the Helmholtz function. The total number of moles in the system was then changed to a new value and the system allowed to come to equilibrium again. The contact angle in the new equilibrium condition could be measured and predicted by taking the adsorption at the solid-liquid and solid-vapor interfaces into account but with line tension completely neglected. The predicted values of contact angle are in closed agreement with those measured indicating line tension plays no role in determining the contact angle of mm-sized water droplets on a polished Cu surface. The surface tension of the solid-vapor interface was approximately constant and equal to the surface tension of adsorbing fluid; that is, the Young equation could be simplified.


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