COMPOSITION OF THE OIL-FIELD WATERS. 
87 
Emery & Co. for the Associated Oil Co. The chloride values are 
accurately determined and are comparable throughout. The figures 
reported for soluble solids in the first four analyses are assumed to 
represent all the constituents except silica and the alkaline earth car¬ 
bonates, and on this basis are comparable with the figures shown for 
the last two analyses. The “alkalinity” values of the first four 
waters are mutually comparable but do not represent alkalinity in 
the sense used elsewhere in this report; no comparable figures for the 
last two waters are available, but their alkalinity is known to be con¬ 
siderably lower than that of the others. 
Partial analyses of water from oil wells near Fellows, Midway field, showing increase of 
salinity with distance from the outcrop. 
Parts per million. 
“Alka¬ 
linity,” 
per cent. 
Chloride 
(Cl). 
Soluble 
solids. 
American Oilfields Co. well 92. 
400 
2,840 
7, 720 
14,480 
17,631 
24,398 
6,630 
8,660 
20, 720 
26,480 
28,970 
39, 700 
0.01300 
.01350 
.01158 
.00625 
American Oilfields Co. well 73. 
American Oilfields Co. well 57. 
American Oilfields Co. well 23. 
Associated Oil Co. well 7°. 
Associated Oil Co. well 3.. 
a See analysis 50, Table 8, p. 73. 
In order to show these relations graphically the determinations 
have been plotted in figure 6. In the figure the horizontal scale repre¬ 
sents the distance between the wells along a line between American 
Oilfields Co.’s well 92 and Associated Oil Co.’s well 3. All the wells 
fall close to this line except Associated Oil Co.’s well 7, which lies 
about 1,200 feet to the northwest. The figure shows fairly well the 
gradation from an essentially meteoric water to a connate water. If 
an analysis of water from still nearer the outcrop could be added it 
would doubtless show a still smaller amount of solids. On the other 
hand, the water from Associated Oil Co.’s well 3 is somewhat more 
concentrated than sea water and contains a slightly larger amount 
of chloride, and waters from points still farther from the outcrop do 
not show any further increase. 
The remarkably regular increase in chloride and soluble solids 
shown by these analyses is not entirely a horizontal gradation, for the 
waters are not all from the same horizon. The water in American 
Oilfields Co.’s well 92 probably occurs about 600 feet stratigraphically 
higher than that in the Associated Oil Co.’s wells. This is suggested 
by the slight irregularities in the curves shown in figure 6, but the 
vertical component is not great enough to detract seriously from the 
significance of this regular and essentially horizontal gradation. 
