TRENDS IN PETROLEUM GEOLOGY 



By A. I. Lb\'Oksen 

 Tulsa, Okla. 



The oil industry, like other great American indnstries, has made 

 effective nse of the most advanced thinking in many scientific fields. 

 This is particularly true of its applications of physics, chemistry, 

 engineering, and geology. As a matter of fact, the steep upward 

 curve of the expansion of the industry during the past quarter cen- 

 tury merely reflects the increasing use of the sciences in the discovery, 

 drilling, producing, refining, and transporting operations. And, of 

 the sciences that have been employed, none has had a more spectacular 

 rise in usefulness than geology and its close relative, geophysics. 



The oil industry differs from most other industries that use the 

 mineral deposits of the earth in one important respect, however, 

 in that its supplies must continue to be replaced by new discoveries. 

 Whereas in the field of coal the supply for generations to come has 

 been discovered, is proved, and is known, the situation in oil is quite 

 the reverse. The oil that our children will use is not yet discovered — 

 and being undiscovered, its location, quantity, and nature are not 

 known. This situation is largely the result of the economic cycle 

 of supply and demand — as the supply increases, the price goes down, 

 and the incentive to discover new supplies wanes. Equilibrium seems 

 to be reached, on the average, when the known reserves are kept at 

 approximately 15 times the current yearly demand — a demand that 

 completely consumes the supply and leaves no residue with which 

 to cushion an emergency. Tlie gas tank of this modern engine of 

 progress must, therefore, be continually replenished and as long as 

 this condition prevails there will be a need for methods and 

 techniques of discovery. 



There is now an estimated known reserve of 18 to 20 billion barrels 

 of oil underground — oil which has been discovered, is blocked out, 

 and is available for use. This quantity is adequate only if new dis- 

 coveries can be made to replace it as it is produced and consumed. 

 The past ability of the industry to maintain discovery has been 



' Read at the Fiftieth Anniversary Celebration of the University of Chicago, September 

 1941. Reprinted by permission from Economic Geology, vol. 36, November 1041. 



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