Interfacial characterization of oil-water systems

Abstract

In the process of producing and transporting crude oil, the occurrence of flow assurance dispersions/solids (water-in-crude oil emulsions, gas hydrates, asphaltenes) can reduce and even arrest the flow of hydrocarbons. By characterizing the interface of the oil and water, the behavior of multi-phase dispersions can be analyzed. This analysis can be used to find the stability of different dispersions. This research work focused on using several oils and brines, in order to characterize oil-water interfaces at conditions similar to field conditions. By creating emulsions with the oils and brines, emulsion stability could be determined by measuring the amount of separated water and the average droplet size. Larger droplet sizes indicated less stable emulsions. The water - oil interfacial tension is used to estimate the interfacial activity of natural surfactants. In general, a lower interfacial tension indicated the presence of more interfacially active natural surfactants, and thus a higher tendency to produce stable water - in - crude oil emulsions . This high interfacial activity has strong implications towards a low gas hydrate plugging risk of oil in the field. Using this information, the strategies to reduce gas hydrate plugging problems in the oil and gas industries can be optimized to reduce the amount of chemicals used, lowering the environmental impact.