40 OIL-FIELD WATERS IK SAN JOAQUIN VALLEY, CAL. 
tions become apparent that do not suggest themselves in a study of 
the original analysis. 
In addition to the three properties of reaction two other factors 
may be taken into account as criteria for comparison. One of these 
factors is the ratio of the chloride to the sulphate radicles, for in 
Palmer’s system these radicles are classed together as strong acids. 
Since the strong acids give rise to salinity, chloride salinity and 
sulphate salinity may be distinguished, and these may conveniently 
be expressed as percentages of the total salinity. For example, the 
sulphate salinity ratio in analysis 31 (shown graphically in fig. 2, 
p. 39) is rS0 4 divided by rS0 4 +rCl, or 13 divided by 22.3 = 58.3 per 
cent (of the total salinity). The other factor is the concentration of 
the solution, or the total amount of dissolved solids. In general, the 
concentration of oil-field waters of any one type is fairly constant, 
but it may vary widely and therefore should not be lost sight of. In 
gome waters it may also be desirable to determine the ratio of 
sulphate to carbonate, though in general this ratio is adequately 
expressed by the proportions of the properties of reaction. 
The calculations involved in the stages leading up to the deduction 
of the properties of reaction may seem long and tedious, but the 
value of the results should more than pay for the necessary labor. 
Adequate comparison is impossible until the analyses have been con¬ 
verted into ionic form; and when this step has been accomplished 
the labor of calculating the reacting values and deducing from them 
the properties of reaction is inconsiderable. 
SOURCE AND STATEMENT OF ANALYSES IN THIS REPORT. 
In order to give an adequate idea of the principles that seem to 
control the composition of the oil-field waters, 88 analyses selected 
from several hundred available for the writer’s study are included in 
this preliminary report. These analyses have been selected, first, 
according to their representation of the chemical variation encoun¬ 
tered; second, according to their position with regard to the oil; 
third, according to the probable accuracy of the analytical work; 
and, fourth, according to their geographic distribution. 
Of the 88 analyses given 30 were made by the Geological Survey, 
17 by the Standard Oil Co., 12 by the Kern Trading & Oil Co., and 
29 by industrial chemists. In most of those made by the Survey all 
the reported constituents were determined and the- percentage of 
error may be computed. The others are partial analyses, the alka¬ 
lies having been calculated by difference. The analyses made by 
the Standard Oil Co. and the Kern Trading & Oil Co. may be accepted 
as reliable and accurate within pretty close limits. The remaining 
analyses are believed to be reliable, but they were made only for 
