Page 95 - Fundamentals of Enhanced Oil and Gas Recovery

83
Enhanced Oil Recovery Using CO 2

each representing an oil of a particular API. Beggs and Robinson [50] neglected the

dependence of oil viscosity on the composition since oils of widely varying composi-
tions have the same gravity. They also neglected the effects of pressure on viscosity.
Formulations are as follows [50]:
• Dead oil:

X
μ 5 10 2 1 (3.16)
oD
where
X 5 yT 21:163
y 5 10 z
z 5 3:0324 2 0:02023γ
0
μ oD is dead oil viscosity in cP, T is temperature in F, and γ is oil-specific

0

gravity in API.
• Live oil:
μ 5 Aμ B (3.17)
oD
where

20:515
A 5 10:715ðR s 1100Þ
20:338
B 5 5:44ðR s 1150Þ
In Eqs. (3.16) and (3.17), μ is live oil viscosity in cP, and R s is dissolved gas ratio
in SCF/STB.

3.2.2.2.9 Mehrotra and Svrcek [39]
They presented a double-logarithm type correlation as follows:

P
log logμ 5 a 1 1 a 2 T 1 a 3 P 1 a 4 (3.18)
ðT 1 273:16Þ

where μ is the viscosity of the crude in mPa.s, T is the temperature in C, P is the
pressure in MPa, and a 1,2,3,4 are the correlation constants given as follows:

a 1 5 0:815991 a 2 52 0:0044495 a 3 5 0:076639 a 4 52 34:5133

It should be mentioned that this correlation was basically developed for CO 2 -satu-
rated bitumen. However, it can be used for crude oils with an error. The use of their

correlation is limited to a temperature range from 23.89 C to 97.22 C and pressures
up to 6.38 MPa.