OUR PETROLEUM SUPPLY MISER 315 



5 billion barrels were classified as oil "in sight" on January 1, 1922, 

 and 4 billion barrels additional as "prospective and possible" and re- 

 coverable by current methods of production (19). A number of esti- 

 mates have been prepared since 1921. 



The individual estimates of the petroleum reserves that have been 

 made in 1921 and subsequent years differ somewhat, but they all 

 possess a similar order of magnitude. Since 1930 the estimates of 

 proved reserves have ranged from 10 to 15.8 billion barrels. 



The proved reserves in the ground, like the stocks of petroleum 

 held above ground, are constantly changing in quantity. They 

 are depleted by the output of producing wells and increased by the 

 discovery of new fields and deeper pools. During the period 1922 

 to 1938, for which figures of proved reserves are available, many 

 large fields were discovered so that, notwithstanding the consequent 

 greatly augmented production, the proved reserves have increased. 



FUTURE PETROLEUM SUPPLY OP UNITED STATES 



The continued discovery of new fields and deeper oil-bearing 

 zones is required to meet future demands, just as it has since the 

 beginning of the industry in the United States. The extent to 

 which new sources of supply are discovered and produced depends 

 upon the payment of such prices by the consumer as will permit the 

 industry to carry the heavy and increasing expense of new explora- 

 tion and to maintain profits. 



Much oil remains to be discovered in new fields and in deeper 

 pools, but the exact location of these fields and the quantity of 

 petroleum they will yield are not known; they will not be known 

 in advance of drilling. Nevertheless, their number, whatever it 

 may be, is definitely limited and each newly found field leaves 

 one less to be discovered. 



The answer to the question "When will the day of petroleum 

 shortage in the United States be reached?" lies not alone in the 

 supply of oil remaining in the ground. It rests also with the 

 geologist to continue to aid in the increasingly difficult problem 

 of discovery, with the engineer to improve drilling technique and 

 to increase recoveries, and with the chemist to continue improve- 

 ments in refining practice. In part, it rests on the price that the 

 public can pay in the future for oil products, and that in turn 

 depends in part on increased efficiency in use. In a large measure 

 it rests on conservation and efficiency in the discovery, development, 

 and production of our future oil fields. 



The future undoubtedly will see continued advances in science 

 and technology affecting the discovery, recovery, refining, and 

 utilization of petroleum. Thus far, these advances have enabled 



