(184a) Microwave-Assisted Demulsification of Tight Crude Oil-Water Emulsions

The main objective of this study is to use microwaves to develop an energy efficient and economical method to demulsify stable crude oil and water emulsions. These crude oil emulsions are formed by high shear mixing of process water and crude oil during pumping, desalting and transportation through wellbores and pipelines and are stabilized by emulsifying agents that form interfacial films at the oil-water interface. These surface-active species, such as asphaltenes, resins, solids, waxes, or commercially available chemical emulsifiers present in the crude, are responsible for the formation of stable emulsions. Tight crude oil emulsions, characterized by suspended droplets on the order of submicron to tens of microns, often cause serious problems to the wellbores and pipelines such as clogging, corrosion, and pump failures. To simulate field conditions, we mixed two crude oils to prepare samples with American Petroleum Institute (API) gravities between 28.9° and 46.0°. These crudes were mixed with water to create emulsions containing between 20% and 80% water. This array of Water-in-Oil (W/O) and Oil-in-Water (O/W) emulsions with different densities and viscosities were mixed at varying shear rates. A series of batch demulsification runs of these crude oil emulsions were done by exposure to microwaves under a well-defined set of parameters such as temperature, power, time, and salinity. To determine the efficiency of phase separation after treatment, final oil-phase water content was measured using Karl Fischer Titration and the water-phase oil content was determined using an Oil and Grease analyzer. Under similar hold times and temperatures, microwave separation methods more effectively separated the phases than thermal separation methods. Energy input analysis was performed from the Power-Time data obtained from each demulsification run. A separation efficiency model was developed based on the energy and mass balance study for the microwave demulsification method.