The mechanism of how asphaltene affects the viscosity of Tahe heavy oil

Abstract

In this paper, the effect of asphaltene on the viscosity of Tahe heavy oil was studied. Firstly, the viscosity of the heavy oil with different asphaltene content was tested. Results showed that more asphaltene would lead to larger viscosity of the heavy oil. Secondly, it is observed that with the increased asphaltene content, there is a synchronous increasing tendency of storage modulus and viscosity. This indicates that asphaltene might form space netty aggregates in the heavy oil and result in the increased storage modulus and viscosity. Finally, causes of such asphaltene aggreggates and the influence mechanism of asphaltene on the heavy oil viscosity was analyzed in depth. It is found that through methylation modification experiments, the active hydrogen was removed from asphaltene molecules. In this way, the intermolecular forces including hydrogen bonding could be weakened. Then the molecular assembly variation of asphaltene aggregates was compared with the heavy oil viscosity. Results revealed that among all kinds of intermolecular forces, the ones related to active hydrogen are more beneficial to the space netty structure of alphaltenes and have more impact on the viscosity.