Page 185 - Geochemistry of Oil Field Waters
P. 185
172 INORGANIC CONSTITUENTS AND PHYSICAL PROPERTIES
Density
Equations that were developed for sea water can be applied to oilfield
waters to obtain approximate values for engineering studies. The density
values (ao) at O°C and atmospheric pressure are related to the chlorinity (CZ)
as follows:
-0.069 + 1.4708 CZ - 0.00157 C12 + 0.0000398 C13 = UO
where CZ = chlorinity (see Table 3.111).
The density is very dependent upon temperature:
where D = a complex function of ao, and temperature and D values can be
obtained from Knudsen’s Hydrographic Tables (Knudsen, 1901).
Vapor pressure
The relative lowering of the vapor pressure of oilfield water can be calcu-
lated with the following equation:
Ap/po = 0.538 x S
where po = the vapor pressure of distilled water at the same temperature,
and S = the salinity (see Table 3.111) (Kellog and Company, 1956, 1966,
1968).
Boiling point
A first approximation of the boiling point elevation can be calculated
from:
At = 0.0158 S
where S = the salinity.
Freezing point
An empirical equation which can be used to estimate the freezing points
is :
t = 4.0086 - 0.064633 ((TO) - 0.0001055 (00)~
See “Density” for an explanation of terms.
