Page 43 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2

Basic Principles, Definitions, and Data 31

In 1977, Standing's classic work [2] was reprinted [30] by the Society of
Petroleum Engineers and an appendix was added by Standing that provides
equations for several of the charts in the original work. Most of the equations
were developed by simple curve fitting procedures. Some equations were based
on computer solutions by other individuals; details of this will not be presented
here and the reader is referred to Appendix 2 of Reference 30. Gas viscosity
can be estimated from the correlations of Cur, Kobayashi, and Burrows [31]
(the basis of Figures 5-6 and 5-7); first the atmospheric value of gas gravity at
reservoir temperature, estimated from gravity and nonhydrocarbon content:

p, = (pl uncorrected) + (N, correction) + (CO, correction)
+ (H,S correction) (5-18)

where (pl uncorrected) = [1.709(10") - 2.062(10-6)yg]T + 8.188(10")
- 6.15( 10") log yg
(N, correction) = yNP[8.48(1O6)logyg +9.59(10")]
(CO, correction) = y,,[9.08(10")logyg + 6.24(10")]
(H,S correction) = yw[ 8.49( lo-') log yg + 3.73( lo")]
is adjusted to reservoir conditions by a factor based on reduced temperature
and pressure:

where a, = - 2.462 118 20E - 00 a, = - 7.933 856 84E - 01
2.970 547 14E - 00 1.396 433 06E - 00
a, = a, =
ap = - 2.862 640 54E - 01 a,, = - 1.491 449 25E - 01
a, = 8.054 205 22E - 03 a,, = 4.410 155 12E - 03
a4 = 2.808 609 49E - 00 a,, = 8.393 871 78E - 02
a5 = - 3.498 033 05E - 00 a,, = - 1.864 088 48E - 01
a6 = 3.603 730 20E - 01 aI4 = 2.033 678 81E - 02
a7 = - 1.044 324 13E - 02 aI5 = - 6.095 792 63E - 04
( = 0.00 060 957 9263)
A reasonable fit to Beal's correlation (Figure 8 of Reference 5) of gas-free or
dead oil viscosity (which is not very precise) is given by Standing:
360 )'
1.8(10')](
0.32+- - (5-20)
T + 200

where a = antilog