This is the 51st consecutive annual report on drilling activity for the United States. Canadian drilling data have been included with these annual reports since 1948; Mexico provided data for the period 1948-1980.

For 1986, Canada showed a 52.3% decrease in total wells drilled (5,991 wells) and a 45.2% decrease in the amount of footage drilled (24,698,184 ft). The 99 new-field wildcat discoveries represented a success rate of 30.9%. Of these discoveries, 44 were in Alberta, 17 were in Manitoba, and 15 were in British Columbia. New-field and new-pool wildcats accounted for 39.2% of the 1,124 exploratory discoveries. In Canada, 55.3% of the 2,033 exploratory wells drilled were successful.

In the United States, total drilling activity during 1986 decreased 38.9% (to 51,045 wells), and footage drilled decreased 39.2% (to 41,651 mi) compared with 1985. There were 692 new-field discoveries--a 31.4% decrease from 1985. The ratio of new-field dry holes to producers was 5.84:1, and the success rate was 14.6%.

Estimates of ultimate reserves reported as discovered in 1983-1986 in the United States are being reviewed by the Joint Task Group on Statistical Integrity of the Committee on Statistics of Drilling. Results of this study will be published in a later issue of the Bulletin.