NATURAL FACTORS AND THEIR RELATED PROBLEMS 609 



WHY PETROLEUM DEPOSITS ARE RARE 



A stiid}^ of the chemical and jDhysical properties of petroleum — its 

 origin, migration, and accumulation — makes clear why its distribution is 

 so wide, but its segregation in commercial deposits so restricted. In the 

 first place, because of its origin it is confined almost exclusively to a cer- 

 tain group of rocks, namely, sedimentary; secondly, it is a liquid at ordi- 

 nary temperatures, susceptible to evaporation when exposed to the air, 

 and never a stable compound, even when confined. Slow distillation is 

 always taking place in crude petroleum, generating gas which tends to 

 expand and cause migration and dissipation of the oil. " In most deposits 

 the tendency to migrate because of the generation of gas is augmented by 

 hydrostatic pressure. Oil is therefore not a stationary, but a migratory, 

 substance. Third, a natural oil reservoir once emptied will never fill 

 again for generations, commonly speaking. 



The WoPvLD^s Future Supply 



In discussing the relative importance of the various countries of the 

 world as ^^roducers of petroleum, the question of probable future pro- 

 ductiveness must often be considered apart from that of their past and 

 present yield, for in some cases the country, like the United States, is at 

 its zenith or past, while other countries, like Persia or Colombia, with 

 little or no production at present, may ofi'er evidence of later becoming 

 important producers. 



According to this table, it is seen that nearly three-fourths of the 

 world's supply is now coming from jSTorth America, including Mexico, 

 and that the bulk of the remainder comes from Eussia. The United 

 States has produced about 60 per cent of the total production to date, 

 while Eussia has produced only about half as much, or a little over 29 

 per cent. As regards future production, it is probably safe to say that 

 Eussia, or possibly even Mexico, will outstrip the United States. This 

 condition is true because of the early and intensive development of petro- 

 leum in the United States, due to the proximity of the fields to markets, 

 the character of our citizens who went into the business, and the attitude 

 of our Government. The last two factors are always important ones and 

 ones that will be in the future, as they have been in the past, the deter- 

 mining ones in many instances. These same two factors are also the 

 dominant ones, almost universally, when it comes to conservation of oil, 

 and it is the balance between the forces of exploitation and those of con- 

 servation that determines the efficiency with which petroleum, as well as 

 other natural resources, is produced and utilized. 



