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Molecular Simulation of Multiphase Interface Characteristics and Microscale Flow Mechanisms of Oil and Brine in Carbonate Reservoir
Zheng Li1,*
1 Chengdu University of Technology, Chengdu, 610059, China
* Corresponding Author: Zheng Li. Email:
The International Conference on Computational & Experimental Engineering and Sciences 2023, 26(3), 1-1. https://doi.org/10.32604/icces.2023.09141
Abstract
Pore structures of carbonate reservoirs are complicated leading to the indistinguishable two-phase flow
mechanisms of oil and brine. This work from the molecular perspective investigates the interfacial tension
of oil-brine two-phase system, the contact angle of oil-brine-carbonatite three-phase system, as well as the
microscale flow mechanisms of oil and brine in carbonate nanopores, especially focusing on the effects of
ion species, salinity, and carbonate surface. The following conclusions can be drawn. (1) Oil-brine interfacial
tension increases with salinity for the same ion species, and increases in the order of KCl, NaCl, CaCl2 and
MgCl2 for the same salinity. The cation mainly affects the interfacial tension, and a larger cation size
corresponds to a lower interfacial tension. (2) The neutral carbonate surface is super-hydrophilic with a
water film between oil droplet and carbonatite. As the salinity increases from 0 mol/L to 3.8 mol/L, the
thickness of the water film increases from 0.6 nm to 1.05 nm, and the contact angle of oil droplet increases
from 145° to 170°. For the same salinity, both the water film thickness and the contact angle in CaCl2 brine
system are larger than those in NaCl brine system. The charged carbonate surface makes the water
molecules oriented, stretching the oil droplet vertically, even with the tendency to strip the oil droplet from
the carbonatite. For CaCl2 and NaCl brine systems, there are critical salinities of 0.82 mol/L and 1.23 mol/L,
respectively. The cross section of the oil droplet is oval when the salinity is smaller than the critical value,
while it becomes circular when the salinity exceeds the critical value. (3) In neutral carbonate nanopores,
water film forms near the nanopore wall which cannot flow, while oil prefers the nanopore center which
will flow under the pressure gradient. Increasing the salinity will decrease the velocity. In charged carbonate
nanopores, both oil and water adsorb on the nanopore wall. There is no velocity slip on the nanopore wall.
Increasing the salinity will strip the oil droplet and a water film will form between the oil droplet and
carbonatite. Besides, the velocity will be enhanced. This work can provide microscale understanding and
theoretical basis for enhancing carbonate reservoir recovery factors.
Cite This Article
APA Style
Li, Z. (2023). Molecular simulation of multiphase interface characteristics and microscale flow mechanisms of oil and brine in carbonate reservoir. The International Conference on Computational & Experimental Engineering and Sciences, 26(3), 1-1. https://doi.org/10.32604/icces.2023.09141
Vancouver Style
Li Z. Molecular simulation of multiphase interface characteristics and microscale flow mechanisms of oil and brine in carbonate reservoir. Int Conf Comput Exp Eng Sciences . 2023;26(3):1-1 https://doi.org/10.32604/icces.2023.09141
IEEE Style
Z. Li, "Molecular Simulation of Multiphase Interface Characteristics and Microscale Flow Mechanisms of Oil and Brine in Carbonate Reservoir," Int. Conf. Comput. Exp. Eng. Sciences , vol. 26, no. 3, pp. 1-1. 2023. https://doi.org/10.32604/icces.2023.09141