Assessment and Development of Heavy-Oil Viscosity Correlations

Abstract

Abstract Heavy oil always poses a great challenge to production and transportation systems due to its high viscosity. This paper evaluates fourteen dead, eight saturated and nine under saturated live oil viscosity correlations against a databank consisting of heavy oil data from various parts of the world with wide ranges of temperature, pressure and fluid compositions. The existing empirical viscosity correlations were mostly developed for significantly lighter oils. Most of them cannot reasonably predict the heavy oil viscosity at low temperatures. Three new empirical correlations for dead, saturated and under saturated oils are developed that are applicable for the heavy oils with API gravity ranging from 10 to 22.3. When compared with the databanks, the new dead oil, saturated and under saturated oil viscosity correlations showed 3 to 50%, 3 to 13% and 22 to 27% improvement over the existing best correlations, respectively. Saturated, Aromatics, Resin and Asphaltenes (SARA) data of some heavy oils were also analyzed to understand the role of the asphaltene and resins in heavy oil viscosity.