Asphaltene Stability in Crude Oils

Abstract

Summary The influence of different factors on the asphaltene stability in crude oils was evaluated. Compositional studies and structural characterization of resins and asphaltenes were carried out to study a possible relationship between these properties and asphaltene deposition behavior. Asphaltenes were obtained by precipitation with n-heptane and characterized by elemental analysis and spectroscopic techniques. Low hydrogen to carbon ratios, high aromaticities, and high condensation of aromatic rings were the main characteristics of the asphaltenes from unstable crude oils. According to these results, the stability behavior of the asphaltenes was influenced strongly by their structural characteristics. However, it was also found that stabilization by means of a commercial inhibitor was affected by the composition of the crude oil. In particular, a high content of basic functionalities in the crude oil can be related to the decrease of the inhibitor's effectiveness (dodecylbenzene sulphonic acid). Based on these findings, some useful suggestions applicable to the oilfield operations are made.