Barrett Resources first well in the Cave Gulch Unit began production in December, 1994, at 10.7 million cubic feet of gas and 116 barrels of oil per day. The elements necessary to define this close-in subsurface prospect were present in 1959. The senior author first recommended the prospect in 1971. Major companies owned the key leases from 1959 to 1994. Everyone had an opportunity to bid on them in 1973. This paper will show: 1959 key data; 1973 subsurface interpretation; 1994 information used to sell the prospect; and results of drilling to date. Reasons why it went undrilled for 35 years will be suggested. One reason may be reliance on questionable subthrust seismic data instead of hard geologic evidence.

Shallow production, from 4600 to 9800 feet, is from numerous lenticular fluvial sandstones in the Paleocene Fort Union and Cretaceous Lance and Meeteetse Formations on a structural closure beneath the South Owl Creek Mountains thrust. Development drilling is incomplete and many pay zones have yet to be perforated. Net pay can exceed 1200 feet and appears to average between 500 and 600 feet for wells drilled to 9000 feet. Ultimate shallow reserves should exceed 500 billion cubic feet of gas.

In addition, a recent 19,000 foot test indicates that overpressured sandstones in the Cretaceous Frontier, Muddy and Lakota formations have significant reserves, and a 21,000 foot test of the Mississippian Madison limestone is underway. Reserves in these deeper units could exceed those in the shallower zones.