102 OIL-FIELD WATERS IN SAN JOAQUIN VALLEY, CAL. 
Analyses of natural gas from Coalinga, Midway, and Sunset fields, Cal. 
1 
2 
3 
4 
5 
6 
i 
Carbon dioxide. 
5.1 
11.1 
34.2 
20.0 
19.7 
20.0 
7.6 
.9 
Oxveren . 
1.1 
.3 
.0 
.0 
.0 
.0 
Methane. 
92.8 
88.0 
61.8 
74.7 
73.8 
62.5 
76.5 
Rthane . 
.7 
4.4 
5.7 
16.4 
15.2 
Nitrogen . 
.9 
2.1 
.9 
.8 
1.1 
.7 
.5 
.0 
99.5 
100.0 
100.0 
100.0 
100.0 
100.0 
100.0 
Heating value (British thermal units per cubic 
foot). 
937 
603 
904 
892 
971 
1,097 
Coalinga field: 
1. Well in sec. 11, T. 19 S., R. 15 E. Analyzed by Kern Trading & Oil Co. 
2. Several wells in sec. 25, T. 20 S., R. 14 E. Analyzed by U. S. Bureau of Mines. (Bur. Mines Bull. 
19, p. 56, 1912.) 
3. Well m sec. 36, T. 20 S., R. 14 E. Analyzed by Smith, Emery & Co. Authority, Associated Oil Co. 
Midway-Sunset fields (samples 4, 5, 6, and 7 collected by G. S. Rogers in July, 1914, and analyzed by G. A. 
Burrell, of the Bureau of Mines): 
4. Well 5, Hal e-McLeod Oil Co., sec. 8, T. 32 S., R. 23 E. 
5. Well 6, Chanslor-Canfield Midway Oil Co., sec. 31, T. 31 S., R. 23 E. 
6. Well 5, Spreckles Oil Co., sec. 32, T. 12 N., R. 23 W. 
7. Well 5, Honolulu Oil Co., sec. 6, T. 32 S., R. 24 E. 
I 
ALTERATION OF HYDROCARBONS BY WATER. 
Despite the close association of petroleum and water in most oil 
fields the chemical relations of the two have apparently never re¬ 
ceived much attention. Many oil men have developed from per¬ 
sonal observation opinions concerning the effect of water on pe¬ 
troleum, but these opinions differ widely and little attempt has been 
made to corroborate them in the laboratory. In fact, petroleum 
chemists have been occupied so largely in working out the complex 
constitution of petroleum and the processes of refining it that we 
know little of the effect on petroleum of any of the substances with 
which it comes in contact underground. The great differences be¬ 
tween petroleum in different regions are doubtless due largely to 
differences in the composition of the original organic matter and to 
differences in age and degree of metamorphism; but some of these 
broader differences, as well as most of the minor variations in the 
character of the oil from any one field, are probably due to the 
local action of natural agents. Of these oxygen and sulphur are 
probably among the most important. 
When oil is exposed to the air for some time it becomes dark, heavy, 
and viscous, and finally passes to asphalt. This change is due chiefly 
to the evaporation of the more volatile constituents but partly to 
oxidation. Thus, if hot air is passed through a so-called paraffin 
oil for several hours the oil becomes black and asphaltic. 1 Simi¬ 
larly, if solid paraffin or a paraffin oil is digested with sulphur it 
becomes black and asphaltic, 2 or if a light asphaltic oil of the type 
1 Jenney, W. P., On the formation of solid oxidized hydrocarbons resembling natural asphalts by the 
action of air on refined petroleum: Am. Chemist, vol. 5, p. 359, 1875. 
2 See Kohler, H., Die Chemie und Technologie der natiirlichen und kiinstlichen Asphalte, p. 119, Braun¬ 
schweig, 1904. 
