THE SEARCH FOR OIL — LEES 237 



The number of oil fields in tlie world in the average category is 

 about 1,500, and the average size is about 500 acres, average depth 

 about 2,500 feet, average initial production per well about 10 tons 

 per day, and average ultimate production about 2 million tons. 



So much for the nature of oil fields. I shall now refer back to my 

 table of production distribution and discuss the question of proved 

 reserves and the prospects of the future. In the table the U. S. A. is 

 credited with proved reserves of 2,000 million tons, or, in other words, 

 about 12 years of supply at the present rate of production. This, 

 however, refers only to proved reserves, that is, the estimated produc- 

 tion yet to be drawn from known fields, and no allowance is made 

 in this figure for new discovery. The rate of new discovery in the 

 States is still a formidable one. But the present decade will show a 

 considerable reduction in this respect on the previous, and this is 

 in spite of great improvements in the technique of oil finding and 

 of the depth capacity of drilling machinery (fig. 4). 



Many estimates have been made in the past of the total oil reserves, 

 as distinct from proved reserves, of the IT. S. A., and each estimate 

 has in turn been disproved by subsequent experience, with the result 

 that there is frequently a disinclination on the part of many to trust 

 the common anticipation of a coming shortage of oil, a disbelief which 

 gains strength from the large potential overproduction at the present 

 day. But notwithstanding past errors, there is no doubt on the part 

 of all responsible American oil geologists, and my own study of the 

 situation adds confirmation, that the bulk of American oil has already 

 been discovered. Fifteen years' supply is already in sight and new 

 discovery may provide for perhaps a further 10 years, perhaps 15 

 years, or perhaps 20 years, but that is the order of expectation. One 

 must not conclude from this that the oil fields of the States will be 

 exhausted within 20 to 30 years from now, because the rat« of decline 

 of oil fields is so slow that it would be impossible to exhaust them 

 in such a short time. But what it does mean is that there will be 

 a decline in total production within a measurable number of years, 

 and a realization of this salient fact is important for the theme of 

 my paper. It is the realization of this fact by the large and power- 

 ful American oil companies that has caused them to intensify their 

 search for new reserves of oil elsewhere in the world, and to compete 

 actively for new concessions wherever they are to be had and in any 

 countries having even remote potentialities, knowing that all the more 

 obvious prospects have been taken up and explored long ago. 



Before leaving the U. S. A. I must answer my earlier question of 

 why that country should have such a dominating position in the 

 world of oil. The answer is twofold: they actually have an enor- 

 mous oil supply, and they have tried harder than any other country. 



