Recent Insights from Computational Materials Chemistry into Interfaces Relevant to Enhanced Oil Recovery

Abstract

Efficient usage of earth's limited oil reserves requires fundamental understanding of the interfacial effects governing oil recovery. As experimental access to such knowledge is often limited, modern simulation techniques are constantly gaining relevance in this field of research. This progress report therefore addresses recent studies of materials chemistry dealing with computational approaches to obtain insights into the interaction between rock surfaces, water, and oil components. It aims both at providing a starting point for newcomers to the field and at equipping experts with an overview of new developments. Being the most prominent mineral in oil reservoirs and the main component of sedimentary carbonate rock, special attention is given to interfaces involving calcite (CaCO3). While the research field still develops in two branches with most studies dealing either with rock–water or rock–oil interaction, it will be important to consider also collective effects at general rock–water–oil interfaces in future investigations.

Mechanism of wettability alteration of the calcite {101̄4} surface

“…12,13 It is known that interaction of salt ions with calcite is responsible for wettability alteration from a strongly oil-wet toward a water-wet state. [14][15][16][17] In particular, low-salinity brines containing monovalent ions result in more water-wet characteristics. It has been concluded from experimental results that the mechanism of wettability modification is related to the affinity of the salt ions to calcite, 18 and theoretical studies have been performed to deepen the understanding.…”

How do ions contribute to brine-hydrophobic hydrocarbon Interfaces? An in silico study

“…However, the interfacial contribution of ions at oil-brine interfaces is not fully understood [9], due to the difficulty of probing nanoscopic phenomena at interfaces by direct experimental observation, and because of the complex chemistry of crude oils [10][11][12]. The discrete character of ions becomes especially important in the tightly confined medium of porous minerals, where continuum theory fails to provide a detailed picture of the ions behavior [13].…”

“…For this purpose, molecular dynamics (MD) simulation is a promising tool for gaining knowledge on the physics of substances enclosed within extraordinary thin spaces [16]. MD simulation facilitates developing new theories and improving existing models for surface and bulk properties of fluids by providing insight into the nature and relative strength of inter-and intra-molecular interactions [13]. Leveraging the strength of MD simulation, Underwood et al studied the salinity dependence of the interfacial tension (IFT) for decane in contact with aqueous NaCl solutions [17].…”