Page 84 - Geochemistry of Oil Field Waters

72 ANALYSIS OF OILFIELD WATERS

4.000 -L

1.00 1.05 1.10 1.15 1.20 I. 5
SPECIFIC GRAVITY
Fig. 3.6. Relationship of the concentration of magnesium to specific gravity for some
oilfield brines.

Calculations. See calculations under “Lithium” in the flame spectrophoto-
metric section, Fig. 3.3, or Table 3.XI:
mgMgx 1,000 = mg/l Mg+2
rnl sample

Precision. In a single laboratory using oilfield water samples containing con-
centrations of 1,470 and 2,000 mg Mg+2/1, the standard deviations were
k36 and +128, respectively. The recoveries were 97.3% and 103.2% respec-
tively.

Calcium (1)

Calcium is determined at the 4226.7 A wavelength with an air-acetylene
flame.