PETROLEUM RESOURCES AND INDUSTRIES 

 the depth being obtained by the rotary and the hole 

 finished by the standard. The "circulation method," 

 a combination of the standard drilling tools and the 

 rotary method of removing the debris from the bot~ 

 torn of the hole by circulating water, is sometimes 

 used. 



Cementing is now nearly always resorted to in 

 shutting off the water. The pumping method, dump- 

 ing the cement from a bailer, and forcing down the 

 cement between discs which fit snugly inside the 

 casing, are among the ways in which the wells are 

 cemented. Two to twenty-five tons of cement are 

 used in the process, seven to ten tons being the 

 usual amount in the deep holes. 



Many of the wells flow of their own gas pres- 

 sure, especially when first brought in, but sooner 

 or later pumping has to be resorted to. The plunger 

 pump, air lift, and various modifications of these 

 standard methods are in use. Steam, gas, and oil 

 engines, and electricity, are utilized for power 

 generation in connection with the pumping opera- 

 tions, while steam is still used almost entirely in 

 drilling and in the large pumping plants along the 

 trunk pipe lines. 



THE OIL DISTRICTS: Eleven principal districts 

 furnish the oil in California, these, in their order 

 from north to south, being as follows: 



Estimated Production 

 San Joaquin Valley Districts for 1914 



Coalinga 15,925,887 bbls. 



Lost Hills 4,830,921 " 



McKittrick 3,820 857 " 



Midway and Sunset .". .". 50,025,843 " 



Kern River 7,030,545 " 



81,634,053 " 

 Coast Districts 



Santa Maria _ 4,303,080 bbls. 



Summer-land and miscellaneous 83,118 " 



Santa Clara Valley 968,421 " 



Los Angeles 2,504,475 " 



Puente Hills .... . 14,130,548 " 



21,989,642 " 

 Total 103,623,695 " 



The relative location of the districts is shown 

 on the accompanying map. 



Coalinga District. This district is the northern- 

 most of the important ones of California and is 

 situated on the southwestern edge of the San 

 Joaquin Valley, in Fresno County, 170 miles south- 

 east of San Francisco. The proved oil-bearing area 

 embraces about 25,154 acres, or forty square miles. 

 It is connected with Monterey, Port Harford and 

 San Francisco Bay by adequate pipe lines. The 

 wells in this district, of which there are now 807 

 82 



