COMPOSITION OF THE OIL-FIELD WATERS. 83 
Table 13. —Analyses of water from different depths in an oil well in the Midway oilfield, 
Cal. 
PROPERTIES OF REACTION IN 
PER CENT. 
Primary salinity. 
Secondary salinity. 
Primary alkalinity. 
Secondary alkalinity. 
Per cent of rS04 in rSCU+rCl. 
Ratio of rC 03 +rHC 03 to rSC>4. 
CONSTITUENTS IN PARTS PER 
MILLION. 
Sodium (Na) and potassium 
(K)o. 
Calcium (Ca). 
Magnesium (Mg). 
Iron (Fe 2 C> 3 ) and alumina 
(AI 2 O 3 ). 
Sulphate (SO 4 ). 
Chloride (Cl). 
Carbonate (CO 3 ) b ... 
Silica (Si0 2 ). 
81 
82 
81 
82 
REACTING VALUES IN PER 
CENT. 
68.6 
67.0 
Alkalies: 
0 
0 
Sodium (rNa) and potas- 
28.6 
31.8 
sium (rK) a. 
48.6 
49.4 
2.8 
1.2 
Alkaline earths: 
a 
K 
2.3 
.2 
Magnesium (rMg). 
• D 
.8 
. 0 
.1 
20 
165 
Strong acids: 
Q 
Chloride (rCl). 
33'. 5 
33! 4 
Weak acids: 
Carbonate (rCOs) &. 
15.7 
16.5 
1,059 
2,809 
ANALYSIS AS REPORTED. 
11 
26 
9.6 
2.9 
Sodium sulphate. 
3.31 
.76 
Sodium chloride. 
108. 40 
281.50 
1.7 
Sodium carbonate. 
41.64 
121. 80 
38 
8.7 
Calcium carbonate. 
1.65 
3.80 
1,125 
2,920 
Magnesium carbonate. 
1.92 
.61 
443 
1,226 
Iron oxide and alumina. 
.10 
12 
17 
Silica. 
.71 
1.00 
c 2,699.3 
7,009.6 
c 157. 73 
409. 47 
a Reported and calculated as sodium but includes potassium. 
i> Reported and calculated as carbonate but probably in part bicarbonate. 
c Potassium, iodide, and borate absent. 
d In hypothetic combinations, in grains per U. S. gallon. 
81,82. Standard Oil Co. well, sec. 30, T. 32 S., R. 24 E. No. 81 represents water from 1,380 feet and No. 
82 water from 1,947 feet. A small gas sand occurs between the two waters, and an oil sand a short 
distance below the lower. Both samples taken while drilling and analyzed by Standard Oil Co. 
Analyses 83 to 85, Table 14, represent the vertical gradation in the 
Kern River field. As these waters are primary alkaline there is no 
sharp change in character comparable with the change from secondary 
salinity to primary alkalinity in the waters of the west side, but the 
same order of succession is observed, carbonate increasing and sul¬ 
phate decreasing as the oil zone is approached. Analysis 86 repre¬ 
sents water from a depth of 5,135 feet or over 3,000 feet below 
the main oil zone. Although occurring over 3,000 feet below the 
deepest of the waters just mentioned it is very similar to it in charac¬ 
ter, showing high alkalies, chloride, and carbonate, and no sulphate. 1 
However, a water encountered at least 2,500 feet above this in the 
same well close to (probably below) the oil zone is very different in 
character; it is a secondary saline brine rather than a primary alkaline 
water, though as would be expected from its position it contains no 
sulphate. So far as is known, this water is much the most concen¬ 
trated water and is the only brine that has been found in the Kern 
River field. An idea of its composition may be obtained from the 
following partial analysis, 2 and the properties of reaction estimated 
from this analysis' are as follows: Primary salinity 89.5 per cent, 
secondary salinity 10 per cent, secondary alkalinity 0.5 per cent. 
1 Compare analysis 44, Table 7, p. 70, which represents water from a depth of 3,860 feet, or about 3,000 
feet below the oil measures at the northern end of the Midway field. 
2 Mendenhall, W. C., Dole, R. B., and Stabler, Herman, Groundwater in San Joaquin Valley, Cal.: 
U. S. Geol. Survey Water-Supply Paper 398, Table 60, p. 294, 1916. 
