INTRODUCTION 

 TABLE 1 



MAJOR PROBLEMS OF GEOPHYSICS f 



(a) General problems, (b) Applied problems. 



delineating subsurface features. The seismograph in particular has been 

 successful in revealing hidden structures favorable for the occurrence of 

 new oil and gas fields. 



Whereas oil originally came entirely from shallow wells, it is now 

 produced in wells which may be as deep as 13,000 feet. In 1946, 106 wells 

 were drilled to depths in excess of 12,000 feet, bringing the total of deep 

 wells in this class to 326. Of the 326 wells, 116 had found production at 

 some level, 99 of these at a depth of more than 10,000 feet. The number of 

 deep wells for 1946 was 66 per cent greater than that for 1945 ; deepest 

 production during this year was obtained from a Louisiana well at 13,778 

 feet.$ In 1947, the average for 154 exploratory holes in southern Louisiana 



t Gutenberg, Geophysics, loc. cit. 



t Ernestine Adams, "Deep exploratory wells on increase," The Petroleum Engineer, February, 



