Role of Asphaltenes and Additives on the Viscosity and Microscopic Structure of Heavy Crude Oils

Role of Asphaltenes and Additives on the Viscosity and Microscopic Structure of Heavy Crude Oils

Type	Journal Article
Author	Lilian Padula
Author	Lia Beraldo da Silveira Balestrin
URL	http://dx.doi.org/10.1021/acs.energyfuels.5b02103
Publication	Energy & Fuels
Date	January 11, 2016
Abstract	An attempt to understand the microscopic origin of the high viscosity of Brazilian heavy crude oils was made combining macroscopic and microscopic techniques. Researchers obserbed a clear relationship between the asphaltene content and viscosity, while the removal of asphaltene via flocculation led to a large viscosity drop, confirming them as the origin of high viscosity. The SAXS analyses of crude oils confirmed the presence of asphaltene aggregates as fractal-like particles of colloidal dimensions. Afterward, a systematic investigation was performed on the effects of a series of additives and physical treatments on the crude oil viscosity. Physical methods did not cause any significant viscosity drop as well as more than 80 additives tested. SAXS measurements on oil samples containing toluene and heptane indicated little effect on the asphaltene nanoaggregates within the dimensions probed by SAXS, confirming a general mode of action based on aggregate dilution instead of disruption.