Summary
This paper presents an experimental study performed to characterize the stability of emulsion samples collected from different Gas/Oil Separation Plants (GOSPs). The first part of the study (Al-Ghamdi et al. 2007) focused on the analyses of separated phases. Many techniques (differential scanning calorimetry, Karl Fischer titration, rheology, optical microscopy, and cryo-scanning electron microscopy) were applied to analyze and characterize the separated phases: crude oil, emulsion, and free water. In the second part of this study, the stability of residual emulsions was investigated against several chemical demulsifiers by using bottle tests and an automated vertical-scan macroscopic analyzer (Turbiscan; Formulaction; Toulouse, France). This instrument is used to obtain kinetics of separation of concentrated and opaque dispersed systems such as emulsions, suspensions, and foams. Interfacial tension measurements were also made to obtain information about the interfacial behavior of samples including viscoelasticity properties of the film. The results of transient emulsion-separation experiments provide some useful insights into their behavior, stability, and tightness. The study highlights the main physicochemical parameters responsible for the varying tightness of these emulsions and should help provide recommendations to optimize their treatment costs and resolve emulsion issues in the GOSPs.