Ind. Eng. Chem. Res. 1993,32, 2183-2186
2183
CORRELATIONS Modeling the Viscosity of Middle-East Crude Oil Mixtures Birbal Singh,'J Adango MiadonyeJJand V. Rao Puttaguntat Department of Mechanical Engineering and Department of Chemical Engineering, Lakehead University, Thunder Bay, Ontario, Canada P7B 5El
A correlation is presented for predicting the effect of temperature and pressure on kinematic viscosity of crude oil mixtures. The correlation is demonstrated to be capable of modeling the viscosities of binary and ternary crude oil mixtures of the Middle East. The overall average absolute deviations obtained with the correlation are 3.8% and 2.7 % for binary and ternary mixtures, respectively. The correlation is simple and convenient to use, and the predictions are based on a single viscosity measurement on the dead oil.
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Introduction Equations to represent the effects of temperature and pressure on kinematic viscosity of crude oils have been presented by several authors (Sanderson, 1949; Hersey and Lowdenslager, 1950; Kouzel, 1965; Beggs and Robinson, 1975; Al-Besharah et al., 1989; Mehrotra, 1990). The model presented by Beggs and Robinson (1975) for saturated-oil viscosity has the form = ArdB (1) where pw = saturated-oil viscosity, p d = dead-oilviscosity, and A, B = functions of R,, given as follows: Clw
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A = 10.715(Rs 100)4'.515
(2)
B = 5.44(Rs + 150)4'.338
(3)
where R, is the solution gas-oil ratio in standard cubic feet/standard barrels. The correlation was developed from more than 2000 experimental data points using 600 oil systems. The equation reproduced the measured data with a standard deviation of 27 % . Al-Besharah et al. (1989) presented a correlation for the effects of temperature and pressure on the kinematic viscosity of three (light, medium,and heavy) Middle-East crude oils and their binary and ternary mixtures, at temperatures ranging from 10 to 50 "C and five pressures (from 14.7 to 8000 psi): - eR(P-14.7) (4) vp-
0
where vp denotes the kinematic viscosity at pressure P (in psi) and vo is the atmospheric pressure viscosity. R was expressed as a linear function of the crude oil density. The average absolute deviations reported by the authors were
