Emulsion Stability Studies Based on the Critical Electric Field (CEF) Technique

Abstract

The production and processing of crude oil most often involve the formation of undesirable emulsions, because of the presence of water and high shear conditions. Crude oil emulsions need to be resolved to produce dry oil as well as oil-free water in a timely manner. The type of equipment, process, and chemical treatment required is determined by the emulsion stability as well as the mechanism of stabilization. Traditional “bottle tests” are used to mimic the system to develop suitable demulsifiers for chemical treatment. More recently, critical electric field (CEF)-based techniques were developed in an effort to measure the stability of an emulsion in quantitative terms. The internal phase ratio (IPR)–CEF technique was subsequently proposed as an expansion of earlier work, to gain additional information related to the mechanism of stabilization as well as the mechanism of demulsifier function. This paper reports new insights and advances made with applications of CEF- and IPR–CEF-based techniques. The principles and approach followed here are not limited to oil field applications only but could be relevant to water-in-oil emulsions in various other industries or applications.