114 
SANTA MARIA OIL DISTRICT, CALIFORNIA. 
ucts are usually separated at the wells, the gas being utilized for 
heat or directly for power and the oil being run into tanks. This 
tank oil still contains gas, most of which, however, gradually passes 
off on exposure to the air, with a consequent lowering of the gravity of 
the oil. Before transportation by steamer it is necessary to pass 
the oil through a partial refining process for the removal of the 
lighter, volatile, more dangerous constituents; this is done at present 
in the refineries at Port Harford and Gaviota. 
COLOR AND ODOR. 
Nearly all of the oil in the Santa Maria district is dark brown in 
color. The exceptions are the black oil from the Arroyo Grande 
field, the reddish emulsion from one of the wells in the Hartnell- 
Brookshire area, and the brown to greenish oil found in certain of 
the wells in the Lompoc field. The heavier oil is the darker; the 
lighter grades show the greenish hues. The darkest oil in the Santa 
Maria field proper is the 19° petroleum from the wells in the eastern 
Western Union group. Some very dark oil is also said to come 
from the Lompoc field. 
The heavy oil gives off an aroma not unlike some grades of lubricat¬ 
ing oil, and, doubtless owing to the absence of hydrogen sulphide in 
solution, has little of the disagreeable odor common to that from 
some of the other California districts. In this district the lighter the 
oil, as a rule, the sharper and less agreeable is its odor. 
GRAVITY. 
The gravity of the oil ranges from 14° to about 35° Baume. The 
heaviest oil (14°) comes from the Arroyo Grande field; 18° to 24° oil 
from the Lompoc field; 19° oil from the eastern group of Western 
Union wells; 24° to 29° oil from the Santa Maria field; and 35° oil 
from the Los Alamos Oil and Development Company’s well and one 
of the Wise & Denigan wells. The average gravity of the oil from 
the Santa Maria field proper is between 26° and 27°, thus putting it 
well into the class of valuable refinable petroleums. 
VISCOSITY. 
The relative viscosity of several of the oils from the Santa Maria 
district, together with similar data for other California oils, is shown 
in the table on page 116. 
CHEMICAL PROPERTIES. 
Few data concerning the chemical properties of the oil from the 
Santa Maria district are at present available for publication except 
