PETROLEUM. 71 



devices, preventing an overproduction ;^ gushers " gone wild " may 

 be capped and brought under subjugation; "blow-outs" may be 

 guarded against and prevented; and losses due to fire, seepage, and 

 evaporation largely nullified through adequate development of stor- 

 age facilities. All these gains will accrue more fully through wide- 

 spread application of well-known engineering technique already 

 successfully practiced in many instances. 



The gas that almost invariably comes forth along with the oil cus- 

 tomarily carries some of the lighter components of the oil itself. 

 These components are recoverable by means of appropriate methods 

 in the form of a very volatile gasoline, which can be blended with a 

 heavier petroleum distillate to form commercial gasoline. Until a 

 few years ago, the recovery of the gasoline suspended in natural gas 

 was neglected, but now a very significant yield of this so-called " cas- 

 ing-head " gasoline is obtained.^ The natural gas is made to yield up 

 its gasoline either through compression, which squeezes out the liquid 

 content, or by absorption, which entices it out by means of a certain 

 type of oil which later is heated and thus forced to yield up in turn 

 the gasoline absorbed.' Even with full gasoline extraction, however, 

 there remains in many fields much more gas than can be consumed 

 by legitimate demand, which necessitates a waste of the surplus, un- 

 less it can be cheaply transported to points where demand exists.* 

 In this connection possibilities open up in connection with processes 

 of liquefaction, by means of which the gas may be compressed into 

 reasonable bounds for transportation.' 



Due chiefly to the decline of pressure upon the escape of natural 

 gas, wells quickly mature and then produce at a declining rate; but 

 recent investigations go to show that even when a well is apparently 

 exhausted, its full quota of oil has by no means been exacted. On the 

 contrary, as demonstrated by established practice in Ohio and else- 

 where, an additional yield may be forced by means of compressed air 

 or its antithesis, a vacuum. The more promising of the two methods 

 consists in forcing compressed air down to the porous oil-bearing 

 formation, thus driving the oil to positions reached by pumping wells. 

 The full possibilities of these methods may not be safely forecast, but 

 they are certainly capable, if widely applied, of increasing by a large 



1 Thus, for example, the flow from Mexican oil wells is at present held down to the 

 transportation capacities available for export, avoiding a tremendous local overproduc- 

 tion. 



■ Production of gasoline from natural gas has grown from 7,000,000 gallons in 1911 

 to 104,000,000 gallons in 1916. 



' The absorption method Is especially adapted to " dry " gas lean in gasoline vapor. 



* When the natural pressure is insufficient or distances too great, the normal trans- 

 portation through pipes is unprofitable. 



" See I. C. Allen and G. A. Burrell, Liquefied products from natural gas : Technical 

 Paper 10, Bureau of Mines, 1912. 



