Page 98 - Petrophysics

PETROLEUM CHEMISTRY 71

TABLE 2.7
CONVERSION OF VISCOSITY MEASURED SAYBOLT UNIVERSAL SECONDS AT Two
AS
TEMPERATURES
TO CENTISTOKES [32]
Saybolt Seconds at Saybolt Seconds at
Centistokes 100°F 2 10°F Centistokes 100°F 2 10°F
2 32.6 32.8 28 132.1 133.0
3 36.0 36.3 30 140.9 141.9
4 39.1 39.4 32 149.7 150.8
5 42.3 42.6 34 158.7 159.8
6 45.5 45.8 36 167.7 168.9
7 48.7 49.0 38 176.7 177.9
8 52.0 52.4 40 185.7 187.0
9 55.4 55.8 42 194.7 196.1
10 58.8 59.2 44 203.8 205.2
12 65.9 66.4 46 213.0 214.5
14 73.4 73.9 48 222.2 223.8
16 81.1 81.7 50 231.4 233.0
18 89.2 89.8 60 277.4 279.3
20 97.5 98.2 70 323.4 325.7
22 106.0 106.7 80 369.6 372.2
24 114.6 115.4 90 415.8 418.7
26 123.3 124.2 100 462.9 465.2

a measured quantity of oil through a glass capillary, yields the viscosity
in centistokes, and (2) the Saybolt viscosity measurement which is the
time (seconds) required for a standard sample of oil to flow through
a standard orifice (ASTM Test D-88). The Saybolt Universal viscometer
is used for refined oil fractions and lubricating oils, and the Saybolt
Furol (“fuel and road oil”) viscometer is used for high-viscosity crude
oils and fractions. (The Furol viscometer has a larger diameter orifice.)
Results of the test are expressed in Saybolt or Furol seconds at a specified
temperature.
Tables 2.7 and 2.8 are used to convert from Saybolt seconds to
centistokes. Absolute viscosity (centipoises) is obtained by multiplying
centistokes by the density of the oil [32].

PETROLEUM CHEMISTRY

Petroleums are frequently characterized by the relative amounts of four
series of compounds. The members of each series are similar in chemical
structure and properties. The four series (or classes of compounds) that
are found in petroleums are: (1) the normal and branched alkane series