Drilling activity during 1958 was statistically lower than the preceding year. Discoveries indicate no new major fields but should add substantially to the total reserves of the area.
There were 21 new-field discoveries: 10 in the Upper Cretaceous, 10 in the Lower Cretaceous, and 1 in the Jurassic. Field extension and new-pool discoveries totaled 25.
Total number of wells drilled decreased by 26% from the previous year. The decrease was reflected almost equally in exploratory and development drilling.
Exploratory tests totaled 337, of which 11.3% were successfully completed.
Geophysical activity was restricted to 727 crew-weeks. This is a decline of 20% from 1957 and a continuation of the pattern started in 1953.