A current viscosity of different Egyptian crude oils: Measurements and modeling over a certain range of temperature and pressure

Abstract

Viscosity is an important characteristic of crude oil. The value and changing of viscosity have essential significance for all events in the transportation pipeline of crude oil. The viscosity of crude oil is chan-ged with temperature and pressure and chemical composition of crude. In analyzing the determination of crude oil viscosity operations, it is usual to use only the temperature dependence of viscosity while the influence of pressure is neglected. Therefore the principal objective of this paper is to obtain an exact model that can successfully predict this important fluid property covering a wide range of tem-peratures and pressures. Moreover, in this paper, a mathematical model of changing the current visco-sity of Egyptian crude oils with changing of temperature and pressure is determined. A total of 6 oil samples of different API gravities ranging from 13.4 to 40.4 is tested. Viscosity is measured in the temperature range from 20 to 150°C, and pressure ranges from 14.7 to 132.3 psi. These measu-rements are determined by using the process viscometer apparatus. The comparison between the experi-mental data and the predicted values indicate that the proposed model successfully predict the experi-mental data with an average absolute relative error of less than 3 % and correlation coefficients (R2) of 0.991. It is observed that it is impossible to generalize a correlation for the crude oil viscosity using only API and temperature because the pressure dependence of viscosity cannot be neglected.