COAST LINE LOS ANGELES TO SAN FEANCTSCO. 



95 



mile 



may he made 



The Fernando and its equivalent post- 

 Monterey formations contain the most 

 important oil reservoirs in the State, 

 owing in great measure to their uncon- 

 formable position upon the underlying 

 Monterey group, which has facilitated 

 the upward migration of the oil originating 

 in the Monterey. In general the Fer- 

 nando sediments consist of more or less 

 incoherent conglomerates and sands, 

 clayey shales, and soft clays. With some 

 exceptions the oil produced by the Fer- 

 nando is of the fuel type, its gravity rang- 

 ing from 11^ to 19"^ Baum^. Lai-ge depos- 

 its of aaphaltum, the residuum from oil 

 escaping into the Fernando from the 

 Monterey group, occur at a number of 

 places. 



The oil in the California fields, as in 

 most others throughout the world, occurs 

 in inclined or sloping beds of porous sand, 

 and these oil sands are usually overlain 

 and underlain by water sands, which are 

 separated from the oil sands by imper- 

 vious clay, shale, or other strata. 



'The principal oil fields adjacent to Los 

 Angeles are those of the Los Angeles dis- 



ajid 



Tlie 



Los Angeles district includes the City 

 field, lying in the city of Los Angeles, 

 and the Salt Lake field, immediately 

 West of the city limits, about 4 

 from its business center. 



The City field was discovered in 1892, 

 when a 155-foot shaft was sunk near a 

 small deposit of brea on Colton Street. 

 The first succesrful well was drilled later 

 in that year on Second Street, and by the 

 end of 1895 there were more than 300 

 Wells. This field forms a narrow belt 

 about 5^ miles long nimiing through the 

 northern part of the city; the total area is 

 about 2 square miles. The wells are from 

 500 to 1,200 feet in depth, and the gravity 

 of the oil ranges from 12^ to 19° Baume. 

 The limits of the field are well defined. 

 The wells have alwavs been small pro- 



necessitatine: pumping, and owin 



wi 



small 



a rapid rate and water has been allowed 

 to enter the oil sands in many areas. 



The first well in the Salt Lake field was 

 drilled in 1901 by the Salt Lake Oil Co., 

 and since 1902 this field has been the 

 chief producer in the Los Angeles dis- 

 trict. The wells are deeper than in the 

 City field, ranging between 1,200 and 

 3,000 feet, and the average gmA-ity of the 

 oil is between 16° and JS'^ Baum^. Con- 

 siderable gas under strong pressure ac- 

 companies the oil, which causes the wells 

 to gush during the early part of their life. 



The oil in the Los Aiigeles district is 

 derived largely from the upper 500 feet 

 of the Monterey group and the basal beds 

 of the Fcrnajido formation. During 1914 

 the district produced about 2, 500, 000 

 barrels of oil, and between 1894 and the 

 end of 1914 it produced over 40,000,000 

 barrels. At present there are about 700 

 producing wells in the district. The aver- 

 age daily production for each well in the 

 City field is about 2J barrels and in the 

 Salt Lake field about 23 barrels. 



The 



gra-v-itT 



nigh they varj^ considerably 

 Thev contain considerable 



sulphur, and owing to the entire absence 

 of light products are of little value for 

 refining, being used almost entirely for 

 fueL The oils produced in the Salt 

 Lake field show a marked siroilarity in 

 general properties, being characterized 

 by a liigh percentage of sulphur. The 

 heavy oils are highly viscous and j-ield 

 considerable asphalt. 



The Puente Hills district, from 12 to 34 

 miles southeast of Los Angeles, was the 

 second oil district discovered in Cali- 

 fornia. The first producing well in it 

 was completed in 1880. Until 1893 the 

 Puente Hills and Santa Clam Hiver 

 Valley districts yielded practically all 

 the oil produced in Califoroia. The 

 average depth of the wells in the Puente 

 Hills district is somewhat more than 

 1,300 feet and the average life of the wells 

 is about 16 years. The gravity of the oil 

 varies between 21° and 32"^ Baume. 



