Page 186 - Geochemistry of Oil Field Waters

PHYSICAL PROPERTIES 173

Viscosity

The viscosity will increase with decreasing temperature and with increas-
ing salinity. The viscosities of sodium chloride solutions of the same ionic
strength can be used to estimate oilfield water vicosities.

Osmotic pressure

A relationship between osmotic pressure (Po) and the depression of the
freezing point at 0°C is (in atmospheres):

The osmotic pressure at other temperatures can be estimated (Kellog and
Company, 1956,1966,1968):

Po x (1 + 0.00367t)

Specific heat

The values for the specific heat, cp, of oilfield waters can be approxi-
mated from the values of an equivalent sodium chloride solution.

Thermal conductivity

The thermal conductivity coefficient, A, can be calculated from thermal
capacities because the ratio of thermal conductivities of two materials is the
same as that of the thermal capacities of equal volumes. The values for X at
various temperatures are available in a “Saline Water Conversion Technical
Data Book” (Kellog and Company, 1956,1966,1968).

Surface tension

The surface tension of an oilfield water increases with decreasing tempera-
ture and with increasing salinity. An empirical formula which can be used to
calculate it is:

75.64 - 0.144t + 0.0399 Cl = surface tension (dynes/cm*)

where t = temperature in Celcius, and CZ = the chlorinity (see Table 3.111;
Kellog and Company, 1956,1966,1968).