Microcalorimetry as a New Technique for Experimental Study of Solubility Parameters of Crude Oil and Asphaltenes

Abstract

Prediction of the potential for precipitation of asphaltenes is very important to the oil and gas industry. This precipitation can occur at various stages of oil production, during extraction from the rocky formation until refining. It is related to the variation of factors such as the crude oil composition and pressure. Incompatibility of oils coming from different streams can also cause undesired deposition of asphaltenes. Models to predict the stability of asphaltenes typically consider solubility parameters of the oil and its fractions, but as yet, no relatively simple experimental procedure has been presented. In this study, a relatively simple experimental procedure was developed relying on microcalorimetry and ultraviolet–visible spectroscopy (UV–vis) to determine these solubility parameters of two samples of crude oil and five of asphaltenes (four extracted from crude oils and one an asphalt residue). Similar results were obtained between these techniques, demonstrating the potential of using them for this type of analysis. Furthermore, the influence of the solvent in determining the solubility parameter of an asphaltene was studied.