Inorganic Solid Content Governs Water-in-Crude Oil Emulsion Stability Predictions

• Published in: Energy & fuels 2009-03, Vol.23 (3), p.1258-1268
• Main Authors: Poindexter, Michael K, Marsh, Samuel C
• Format: Article
• Language: English
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/ef800652n

Solving oilfield emulsion problems is often addressed with the field bottle test. This widely used and informative method uses fresh samples and readily generates a number of emulsion stability parameters that aptly describe the diverse aspects of oil−water separation, namely, water drop, oil dryness, and interface quality. Bottle test data by itself is not predictive because all of the parameters are dependent. Demulsification depends upon the conditions used to resolve the emulsion and the crude oil components that inherently stabilize emulsions. By coupling field bottle test data with subsequent characterization of the same samples used in the field, it is possible to gain insight into the factors that describe and possibly determine emulsion stability. Past work using 12 different crude oils showed that inorganic solid content was the most informative parameter in describing many aspects of emulsion stability. Higher solid levels resulted in more stable emulsions. Further field studies and laboratory analyses have doubled the sample size of the original data set and nearly doubled the number of potential descriptive variables. The characterization data is multivariate (i.e., described by many variables) to account for the chemical diversity of crude oil emulsions. In this study, a broad spectrum of oils with American Petroleum Institute (API) gravities ranging from 10−31° and their associated water were characterized using 18 different parameters. Statistical analyses of the expanded data set yield results that agree with the conclusions set forth in the original study. Inorganic solid content remains the most descriptive variable in predicting emulsion stability.