Detection and Impact of Carboxylic Acids at the Crude Oil–Water Interface

Abstract

The impact of surface active indigenous components on interfacial tension (IFT) of crude oil–water systems is an important parameter in many aspects of crude oil production such as emulsion stability, reservoir wettability, and capillary number calculations. These components may affect productivity across the reservoir due to variations in concentrations. In most cases simulation of IFT is not taking interfacial activity into account and is purely based on oil bulk properties. In this paper we examine two crude oils and their subfractions such as maltenes, deacidified crude, and natural acidic components. Films were prepared at the toluene–water interface with crude oil and its various fractions and studied for interfacial activity and chemical compositions. The chemical analysis of the interfacial active material indicated that carboxylic acids are preferentially adsorbed or concentrated at the oil/water interface. Infrared spectroscopic analysis of the interfacial films clearly demonstrates that carboxy...