Salinity-dependent alterations of static and dynamic contact angles in oil/brine/calcite systems: A molecular dynamics simulation study

Abstract

In this study, classic Molecular Dynamics (MD) simulations with established force fields were first performed to investigate the salinity effects on the static contact angle of a n-decane droplet immersing in the water atmosphere within a calcite nanochannel to advance our microscopic understanding on low salinity flooding. By applying an external body force, dynamic contact angle of n-decane in the water phase was also studied in the presence of various salt concentrations based on Non-Equilibrium MD (NEMD) simulation. The predicted n-decane static contact angles are around 59.68º ± 0.26º, which agree well with experimental results in previous studies. A reduction of the static contact angle of the nanodrop is observed with the increase of salinity, which implies an enhancement of surface hydrophilicity. Under flow conditions, the deformation of nanodrop, as evidenced by the centre of mass analysis, becomes faster by increasing the salt concentration. The recovery/mobility of the n-decane 2 nanodrop is, however, still significantly restricted by the adsorption interaction between the substrate and n-decane phase, which may lead to droplet snapping off and/or breaking up into small droplets.

Atomistic Insight into the Behavior of Ions at an Oil-Bearing Hydrated Calcite Surface: Implication to Ion-Engineered Waterflooding

“…21 In later work, the salinity-dependent deformation of a nanodroplet of n-decane on a calcite substrate was studied, and the reduction of contact angle correlated to the increasing salt concentration of the aqueous environment. 22 Recently, Koleini et al observed a direct relationship between the extent of benzoic acid adsorption onto calcite and the concentration of sodium cations in the aqueous interface region. 23 They also pointed out the importance of ion pairing in the brine film separating hydrocarbon phases and the pore wall of carbonates.…”

Movement behavior of residual oil droplets and CO2: insights from molecular dynamics simulations

“…In this model, the parallel Simulator (LAMMPS) free software package (Mehana et al 2018;Zhao et al 2020;Liu et al 2017b;Yan et al 2017b) was used and the simulation results were visualized and processed by VMD and Ovito. The structure of each molecule is first optimized, followed by the optimization of the potential energy of the initial configuration.…”

“…Yu et al (2020) studied the contact angle of water and brine as a function of temperature, pressure, salinity, ion type, and gas content by using MD simulation and compared the results with the literature data. Zhao et al (2020) 2021) studied the intermolecular interactions between crude oil compositions including saturated hydrocarbons, aromatic hydrocarbons, resins, asphaltenes, and amphoteric surfactants 3-(decyl dimethylhydrazone) propane-1-sulfonates (DDPS). From the research mentioned above, it is exemplified that the molecular dynamics simulation technique has been an effective tool to study flow and displacement at the nanoscale (Fang 2019;Fang et al 2020).…”

Atomistic-scale investigations of hyperthermal oxygen–graphene interactions via reactive molecular dynamics simulation: The gas effect

“…However considering the multiple influential factors, a clear understanding of the AO impact effects leading to the disintegration is still experimentally challenging [21][22][23]. To this end, molecular dynamics (MD) simulations can be used as an alternative to investigate AO degradation mechanisms on solid surfaces [24][25][26][27].…”