Page 75 - Introduction to Petroleum Engineering

OIL PROPERTIES 59
B
µ = A µ oD (3.21)
o
with
.
.
A = 10 7 ( R +100 ) −0 515 (3.22)
s
.
.
B = 544 ( R +150 ) −0 338 (3.23)
s
where μ is dead oil viscosity calculated in the first step and R is solution
s
oD
GOR (SCF/STB). Oil with dissolved gas is often called “live” oil. Live oil and dead
oil have analogs in the world of carbonated beverages.
Example 3.4 Dead Oil Viscosity
Calculate dead oil viscosity for a 35°API oil at 220°F.

Answer
Substitute values into Equation 3.20:
(
log ( µ + 1) = 733 10 − . 0 0251 35) = . 046
.
( 220) . 0 564
oD
10
µ oD = 10 046 − =11 90 cp
.
.

Example 3.5 Live Oil Viscosity
Calculate live oil viscosity for a 35°API oil at 220°F with 350 SCF/STB of
dissolved gas.

Answer
Combine the dead oil viscosity from the previous example with the above
values and Equations 3.21 through 3.23 to find live oil viscosity:

.
.
A = 10 7 (350 +100 ) −0 515 = 046
.
.
B = 544 (350 +150 ) −0 338 = 067
.
.
.
=
B
.
µ = A µ oD (0441 90. )( . cp) 064 = 071 cp
o
The plot in Figure 3.6 shows results for the correlation of Equations 3.20 through
3.23 with the properties of Examples 3.4 and 3.5. We consider R varying from near
s
0 up to 350 SCF/STB.