Desorption of hydrocarbon chains by association with ionic and nonionic surfactants under flow as a mechanism for enhanced oil recovery

TL;DR

This study uses simulations to investigate how different surfactants facilitate hydrocarbon desorption from surfaces under flow, revealing nonionic surfactants as the most effective for enhanced oil recovery.

Contribution

The paper provides the first detailed simulation-based analysis of hydrocarbon desorption mechanisms with ionic and nonionic surfactants under flow conditions.

Findings

Nonionic surfactants are most effective in hydrocarbon desorption.

Desorption efficiency varies with surfactant concentration and flow conditions.

Mechanisms of desorption differ between surfactant types.

Abstract

The need to extract oil from wells where it is embedded on the surfaces of rocks has led to the development of new and improved enhanced oil recovery techniques. One of those is the injection of surfactants with water vapor, which promotes desorption of oil that can then be extracted using pumps, as the surfactants encapsulate the oil in foams. However, the mechanisms that lead to the optimal desorption of oil and the best type of surfactants to carry out desorption are not well known yet, which warrants the need to carry out basic research on this topic. In this work, we report non equilibrium dissipative particle dynamics simulations of model surfactants and oil molecules adsorbed on surfaces, with the purpose of studying the efficiency of the surfactants to desorb hydrocarbon chains, that are found adsorbed over flat surfaces. The model surfactants studied correspond to nonionic and cationic surfactants, and the hydrocarbon desorption is studied as a function of surfactant concentration under increasing Poiseuille flow. We obtain various hydrocarbon desorption isotherms for every model of surfactant proposed, under flow. Nonionic surfactants are found to be the most effective to desorb oil and the mechanisms that lead to this phenomenon are presented and discussed.