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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 63 (1979)

Issue: 8. (August)

First Page: 1168

Last Page: 1203

Title: North American Drilling Activity in 1978

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


Total drilling activity in North America increased in 1978 compared with 1977. The 56,088 total wells drilled in the United States, Canada, and Mexico is an increase of 5.9% compared with 1977, and the 48,287 mi of footage drilled is a 6.7% increase from 1977.

Canada showed an increase of 15.7% in total wells drilled (7,170) and a 20.5% increase in the amount of footage drilled (25,297,101). The 213 new-field wildcat discoveries represented a success of 46.6%, an all-time high. Of these discoveries, 100 were in Alberta and 92 were in Saskatchewan. The new-field and new-pool wildcats accounted for 74.5% of the 1,711 exploratory discoveries. In Canada, 54.4% of the 3,144 exploratory wells drilled were successful.

In 1978 Mexico drilled 406 exploratory and development wells, a 32.2% increase compared with 1977. Of this number, 83 were exploratory and 323 were development. New-field wildcat drilling accounted for 62 discoveries with a success of 32.3% (the success percentage does not include wells suspended due to mechanical failures). Overall exploratory success was 75.7%, resulting in 28 discoveries, 11 of which were in the northeast zone, 1 in the north zone, 6 in the combined Poza Rica district and Vera Cruz embayment, and 10 in the south zone.

In the United States drilling activity increased 4.4% (48,512 wells) and footage drilled increased 7.5% (43,761 mi) compared with 1977. There were 983 new-field discoveries--a 2.1% decrease from 1977. The ratio of dry holes to producers was 5.62:1, and the success was 15.1%, which is substantially higher than the usual 9 to 11%.

Estimates of ultimate reserves discovered in 1978 in the United States showed an increase in volume of gas and a decrease in volume of liquids from those discovered in 1977. The new fields in 1978 discovered an estimated 479.49 million bbl of oil and condensate and 4.9 Tcf gas. However, 1978 production remains significantly greater than the amount found.

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