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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 62 (1978)

Issue: 8. (August)

First Page: 1275

Last Page: 1310

Title: North American Drilling Activity in 1977

Author(s): Robert R. Johnston (2)


Total drilling activity in North America increased in 1977 compared with 1976. The 52,983 total wells drilled in the United States, Canada, and Mexico is an increase of 11.6% compared with 1976, and the 45,267 mi of footage drilled is a 15.6% increase over 1976.

Canada showed an increase of 9.0% in total wells drilled (6,197) and a 14.2% increase in the amount of footage drilled (20,994,767). The 468 new-field wildcat discoveries represented a success of 44.7%; an all-time high. Of these discoveries, 146 were in Alberta and 36 were in Saskatchewan. The new-field and new-pool wildcats accounted for 68.4% of the 1,498 exploratory discoveries. In Canada 53.5% of the 2,801 exploratory wells drilled were successful.

In 1977 Mexico drilled a total of 307 exploratory and development wells. This number represents a 8.6% decrease compared with 1976. Of this number, 78 were exploratory and 229 were development wells. New-field wildcat drilling accounted for 26 discoveries with a success of 49% (the success percentage does not include wells suspended owing to mechanical failures). Overall exploratory success was 38.5%, resulting in 30 discoveries, 10 of which were in the Northeast Zone, and 20 in the South Zone.

In the United States total drilling activity increased 12.1% (46,479 wells) and footage drilled increased 16.0% (40,722 mi) compared with 1976. There were 1,004 new-field discoveries--the highest since 1956. The ratio of dry holes to producers was 5.08:1, and the success was 16.5%; which is substantially higher than the usual 9 to 11%.

Estimates of ultimate reserves discovered in 1977 in the United States showed an increase in volume over those discovered in 1976. The new fields in 1977 discovered an estimated 531.42 million bbl oil and condensate and 4.5 Tcf gas. However, 1977 production remains significantly greater than the amount found.

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