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Interfacial tension plays an important role in reservoir mechanisms and in the production and processing of crude oil with coproduced water. Natural surfactants adhere to the oil/water (O/W) interface, which reduces the interfacial tension and in some cases leads to a solidified interfacial film with a significant impact on emulsion stability. These technical challenges are a result of the chemistry of the petroleum system, and hence optimization of production depends on a better understanding of this. The properties and composition of the interfacial film have been the subject of many studies. In this study, films of oil-related components were generated at the interface between oil and water. The interfacial material was recovered by skimming the interface remaining after repeated solvent washings. The recovered material was analyzed using Fourier transform infrared spectroscopy by attenuated total reflectance (FTIR ATR) to obtain both quantitative and qualitative information about the composition of th...

Fourier transform infrared spectrometry (FTIR) spectra were measured for 16 distillation cuts obtained from two bitumens using a deep vacuum fractionation apparatus. Three regions of the spectra were deconvoluted into peaks each associated with a known type of vibration: (1) aliphatic C–H stretching in the 2800–3000 cm–1 region, (2) aliphatic C–H scissoring/symmetric deformation in the 1350–1400 cm–1 region, and (3) aromatic C–H out-of-plane bending in the 680–900 cm–1 region. The distribution of chemical structures in the oils were assessed, and preliminary correlations were identified between measured physical properties (density, atomic H/C ratio, and molecular weight) and the quantified peak areas obtained from the FTIR spectra. A preliminary method was proposed to generate physical property distribution data for crude oils based on distillation and FTIR data. The method predicted the density, atomic H/C ratio, and molecular weight of the distillation cuts, with average deviations less than 0.8, 1.4, ...

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...