ABSTRACT

Approximately 3,860 well completions have been recorded in central Montana since the discovery of oil at Devil's Basin Field in 1919. Sixty fields have been discovered, and cumulative production for the area through 1991 was 130,653,797 barrels of oil.

Graphs of yearly well completions since 1919 indicate three major cycles in drilling activity within central Montana. The first cycle was dominated by the development of Cat Creek Field. The highest recorded yearly production for central Montana occurred in 1961, near the peak of drilling activity for the second cycle. The highest number of completions recorded in any one year in central Montana occurred in 1974, or in the third major cycle of exploration and development activity.

The number of well completions during 1991 was lower than any year since 1943. Production reported during 1991 was nearly equivalent to that reported during 1954.