Controlled In-Line Generation of Stable Oil–Water Emulsions for Enhanced Oil Recovery

Emulsions have been widely used in many industrial applications, and emulsion flooding is applied as an effective chemical enhanced oil recovery technique and used for acid treatment of the reservoir rocks. Most of the techniques used for supplying emulsions to the oil fields are batch preparation methods, which generate a batch of emulsion by using homogenizers or by circulation of water and oil with pumps. Emulsion generated through these methods suffers from separation with time, losing its main properties, making it inefficient, less cost-effective, time and power consuming. This paper investigates a novel method for fully controlled in-line generation technique providing fresh and on-demand emulsion to be used instantaneously in the oil field. This method is based on using Liquid–liquid ejector with control valves for mixing water with oil generating a fresh and stable emulsion instead of using a premixed batch of stored emulsion. The performance of the ejector for generation of invert and direct emulsion is studied experimentally. Diesel and water were used as the two liquids forming surfactant-stabilized emulsion. Emulsion stability, external phase, droplet size distribution and emulsion rheology are also investigated experimentally of the generated emulsions. The results showed that the fully controlled ejector is an efficient device for in-line emulsion generation of both water-in-oil (Invert) and oil-in-water (Direct) emulsions at specific and required ratio. For water salinty of 10 g/l or less, the external phase was always water phase, while for salinity of more than 15 g/l the continuous phase of the resulted emulsion is always oil.