Tight brine-in-oil emulsions and related high viscosities are common oil field problems experienced in mid-to late-life. Emulsions can have a detrimental effect on water separation efficiency, and costs for injection equipment and demulsifier chemicals are high. It is commonly assumed that asphaltenes play a dominant role in emulsion formation, although in some crudes it was found that resins play a role in emulsion formation, especially the carboxylic acids. For the asphaltenes, polarity, and crude oil aromaticity play an important role in their interactions at the oil-water interface, and to a lesser degree the brine pH. For the resins, pH plays an important role, as carboxylic groups are mostly active when de-protonated. In this article, we studied the role of asphaltenes in oil/water emulsions by application of Critical Electrical Field measurements in topped oil and de-asphalted topped oil. The emulsion stability was measured for a range of water cuts (from 2 to 60%), brine pH, temperature, and shear rates.
This paper presents an overview of the different flow assurance issues associated with naphthenic acids. In field development projects a good understanding of naphthenic acid phase behavior is essential to avoid unplanned plant changes and deferment. Good data on naphthenic acid content and speciation is obtained by using a representative sample. Basic measurements (e.g. TAN) are not sufficient to obtain a detailed understanding of the flow assurance issues regarding a particular crude oil. Infrared spectroscopy and mass spectrometry, high and low resolution, are the preferred tools for analysis of crude oils. The target naphthenic acid species, e.g. ARN or fatty acids will dictate the best suited method selected for analysis. Geochemical analysis of crude oils has helped to highlight some common features which can be used for prediction purposes. For bound soap scale-forming crude oils, a large amount of complexed acids result in emulsions which are difficult to break. Chemical treatments are needed and these should be identified early in the project stages. For soap scale-forming crude oils chemical treatment requires in depth analysis of topsides equipment and impact on existing chemical portfolio. Surveillance of soap scale-forming crude oils is possible using readily available equipment. For soap emulsion-forming crude oils, paraffin precipitation adds to the stability of the emulsion formed. Chemical treatment and heat is required for best results. Use of stock tank sample properties can be used for predictions regarding the type of naphthenic acid issue to be expected for particular crude oil sets.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.