Microwave-assisted demulsification for oilfield applications: a critical review
Heriberto Díaz Velázquez, Diego Guzmán‐Lucero, Rafael Martínez‐Palou
Abstract
In the Oil Industry, part of the extracted crude oil is commonly found in form of emulsions, mainly as water-in-oil (W/O) and oil-in water (O/W), emulsions, and more complex emulsions are less frequent but can also be found, such as water-in-oil-in-water (W/O/W) and oil-in-water-in-oil (O/W/O). These emulsions must be broken before the starting of the oil refining process because water generates operational problems like increasing crude viscosity, corrosion of equipment, piping and clogging of pumps and equipment, causing unscheduled production stoppages. O/W emulsions, can also be intentionally generated as a strategy to reduce the viscosity of very heavy crudes and facilitate their transport to the storage, and processing center. However, in any case, these emulsions must be broken before the crude is processed. Different technologies employing chemicals, electric fields, membranes, biological techniques, ultrasound and microwaves have been studied to favor the breaking of O/W emulsions. Microwaves have proven to be an excellent alternative to break emulsions quickly, efficiently, and with minimal energy losses. This paper review accounts for the research studies on the microwave-assisted breaking of W/O and O/W emulsions for oilfield applications with and without the simultaneous application of demulsifying chemicals. The possible mechanisms by which microwaves accelerate emulsion breakage, and their advantages for a more sustainable industry are also discussed.