Molecular Dynamics Studies of Fluid/Oil Interfaces for Improved Oil Recovery Processes

Abstract

In our paper, we study the interface wettability, diffusivity, and molecular orientation between crude oil and different fluids for applications in improved oil recovery (IOR) processes through atomistic molecular dynamics (MD). The salt concentration, temperature, and pressure effects on the physical chemistry properties of different interfaces between IOR agents [brine (H(2)O + % NaCl), CO(2), N(2), and CH(4)] and crude oil have been determined. From the interfacial density profiles, an accumulation of aromatic molecules near the interface has been observed. In the case of brine interfaced with crude oil, our calculations indicate an increase in the interfacial tension with increasing pressure and salt concentration, which favors oil displacement. On the other hand, with the other fluids studied (CO(2), N(2), and CH(4)), the interfacial tension decreases with increasing pressure and temperature. With interfacial tension reduction, an increase in fluid diffusivity in the oil phase is observed. We also studied the molecular orientation properties of the hydrocarbon and fluids molecules in the interface region. We perceived that the molecular orientation could be affected by changes in the interfacial tension and diffusivity of the molecules in the interface region with the increased pressure and temperature: pressure (increasing) → interfacial tension (decreasing) → diffusion (increasing) → molecular ordering. From a molecular point of view, the combination of low interfacial tension and high diffusion of molecules in the oil phase gives the CO(2) molecules unique properties as an IOR fluid compared with other fluids studied here.

Molecular dynamics simulations of the role of salinity and temperature on the hydrocarbon/water interfacial tension

“…However, more recently, complex mixtures consisting of alkanes, cycloalkanes and aromatic molecules [15,16] even including an oil polar fraction [17] have been considered, recognizing the importance that the composition has in the properties of crude oils. These theoretical simulations allow us to understand structure and properties of the interface.…”

Potential applications of cyclodextrins in enhanced oil recovery

“…(1)). The interfacial tensions in biphasic and triphasic planar interfaces were calculated using a Gibbs formulation of the interfacial tension [25], written in terms of pressures (Eq. (2)), where the distances L a and −L b determine the limits of the interfacial region, and p T (z) and p ab (z) are the tangential and normal components of the pressure tensor, respectively.…”

“…There have been a large number of reports in the literature dealing with simulations of the oil-brine-rock interface [25][26][27][28][29], which are especially useful when experimentally inaccessible molecular level information is desired. Molecular modeling provided new insights into the interaction between the CD and the other constituents of the oil-brine-rock system.…”

Molecular dynamics study of oil detachment from an amorphous silica surface in water medium

“…Some experiments on detachment of oil drops from silica substrate were carried out, and the mechanisms of oil detachment from substrate had been analyzed [4][5][6][7][8][9][10]. Recent papers [4,5] show findings that the detachment process of oil from silica surface involves three stages.…”

“…There are also some experiments where different organic pollution is used to do simulations. These involve the simulations about adsorption and detachment of oil on the solid surface [6][7][8][9][10][11][12][13]. The simulation objects of oil molecules include Pyridine and Alkyl Pyridine [9], dodecane [10], organic methanol [11] and so on.…”