Molecular Dynamics Methodology for the Evaluation of the Chemical Alteration of Wettability with Organosilanes

Abstract

In this work, a methodology to evaluate and represent the wettability alteration phenomenon caused by the action of organosilane surfactants using molecular dynamics simulations is presented. This methodology is based on four major steps: (i) the tuning of the energetic parameter of the surface potential to achieve an adequate description of the initial wettability state, (ii) the representation of the adsorption/reaction of the surfactant on the surface, (iii) the evaluation of the coverage degree of the surface and the alteration of the wettability promoted by the surfactant, and (iv) the prediction of the alteration of the wettability of the surface in contact with a hydrocarbon phase. To evaluate this methodology, a case study is presented, in which the variation of the contact angle of water drops on a glass surface by the action of the surfactant C8F17CH2CH2Si–[O–CH2CH3]3 is determined. The methodology results in an adequate reproduction of the contact angle of water drops on untreated surfaces (24.7°) and enables the calculation of the adsorption energy of individual molecules on the surface (44.93 kJ/mol). Additionally, it was found that, with a surfactant surface concentration of 0.76 μmol/m2, the water contact angle on the surfactant-covered surface is properly reproduced (94°). This methodology is sufficiently robust to extend the results obtained for the water system to the evaluation of the contact angle of a system, where n-heptane is the fluid phase (60.7°). All of these results are in excellent agreement with experimental findings. These procedures have shown that the presence of surfactant molecules reduces the affinity of the fluid phase (water or n-heptane) with the surface, increasing the compactness and height of the resulting drop.

Dynamic Molecular Modeling and Experimental Approach of Fluorocarbon Surfactant-Functionalized SiO2 Nanoparticles for Gas-Wettability Alteration on Sandstones

“…On the other hand, to represent the adhesion energies, a tuning procedure was made to estimate the excess energy of the surface , using the experimental contact angle of the brine droplet (123°). Therefore, the wettability state of the restored sample was represented properly by the wall potential.…”

“…In this sense, molecular dynamics (MD) simulations contribute to obtaining valuable physical insights from an atomistic description of the heterogeneous system, describing how the interaction energies change due to the proposed treatment (wettability modifiers such as nanoparticles or surfactants). Hence, the molecular simulations have become a powerful tool to understand the interfacial phenomena based on the study of the atomistic interactions by in silico experiments. − Molecular dynamics models have widely been used to understand the interfacial phenomena in the IOR/EOR process, ,, wettability alteration, − and interfacial tension reduction, − among others. In the specific case of the fluorocarbon surfactant applications, molecular dynamics studies are focused on the wettability alteration ,, and ultralow interfacial tension. − The results reported show a suitable representation by molecular dynamics simulations of the contact angles of water and oil droplets measured experimentally.…”

“…Hence, the molecular simulations have become a powerful tool to understand the interfacial phenomena based on the study of the atomistic interactions by in silico experiments. − Molecular dynamics models have widely been used to understand the interfacial phenomena in the IOR/EOR process, ,, wettability alteration, − and interfacial tension reduction, − among others. In the specific case of the fluorocarbon surfactant applications, molecular dynamics studies are focused on the wettability alteration ,, and ultralow interfacial tension. − The results reported show a suitable representation by molecular dynamics simulations of the contact angles of water and oil droplets measured experimentally. Also, in wettability alteration evaluations from an initial water-wetting state to a gas-wetting state, the calculation of the interaction energies shows an important reduction of the solid–liquid interaction promoted by the fluorocarbon surfactant, at least of 49 and 37% for water and n- decane, respectively. , Sepehrinia and Mohammadi studied through molecular dynamics simulations the wettability alteration using fluorinated SiO 2 nanoparticles.…”

Experimental and molecular dynamics study into the surfactant effect upon coal wettability

“…The lower energy and greater negative interaction energy could spur the steadier adsorption. 38 However, the interaction energy of the simulation system only represents the interaction strength between the surfactant and coal surface, which is not equal to the thermodynamic adsorption energy. 39 The interaction energy is defined as the difference between the energy of the complex and the sum of the energies of the monomers constituting the complex.…”

Molecular Interactions between Asphaltene and Surfactants in a Hydrocarbon Solvent: Application to Asphaltene Dispersion

“…Thanks to technology development, especially breakthroughs in computational capacity, molecular dynamics (MD) simulations draw tremendous attention. Via MD simulations, researchers have focused more precisely on different phenomena at the molecular scale, e.g., liquid-liquid and liquid-solid interactions [31][32][33] and interactions between fractions of heavy oils [34][35][36][37]. Several theoretical investigations have been performed to spotlight an aggregation process and colloidal behavior of asphaltene molecules in solvents [38][39][40][41][42][43][44][45][46].…”