(610h) Understanding Interfacial Properties of Octane-Water-Rock System Using Monte Carlo Simulation

Understanding the interfacial properties of the hydrocarbon-water system is important for many industrial applications, especially for the enhanced oil recovery process. In our recent work, we have traced octane-rich liquid-water-rich liquid (LLE) saturation curves over a wide range of temperatures, pressures and compositions. We are now interested in studying the interfacial properties of this mixture at different rock surfaces, for example at graphite and silica surfaces. We are also interested in understanding how these fluid-rock wetting properties are influenced by carboxylic acids. In this presentation, we describe our efforts to use Monte Carlo simulations to study the wetting behavior of the water-octane mixture. We present results that show how wetting properties, such as the contact angle of a water droplet at a silica/graphite surface in a mother octane phase, evolve with temperature, pressure and composition. These properties are computed via a combination of direct grand canonical simulations and various expanded ensemble schemes. Analogs of these techniques are used to examine the behavior of different carboxylic acids at the rock/fluid and octane/water interfaces. Results are presented to show the effect of temperature, pressure, composition and chemical nature of the carboxylic acid on the wettability of rock surfaces.