Exploratory drilling in western Nebraska registered a 35% increase while development drilling declined 4.8% from 1955 activity. In Colorado, exploratory and development drilling continued to decline with an 18% decrease in exploratory tests and a 28% decrease in development wells from 1955 activity. The greatest concentration of drilling activity continued to be along the Cretaceous productive fairway in the Denver basin. Total geophysical activity increased in Colorado and declined slightly in western Nebraska, with the lag in Denver basin activity being offset by increased activity along the Las Animas arch and in western Colorado.

Total geophysical activity increased markedly over 1955, with most of the increase attributed to southeastern and western Colorado.

The majority of discoveries in western Nebraska and Colorado were again concentrated in the Cretaceous sandstones of the Denver basin. More exploratory drilling was directed toward the pre-Cretaceous objectives along the Chadron-Cambridge arch, Denver basin, and Las Animas arch-western Dodge City basin; Pennsylvanian discoveries on the Las Animas arch and a Lyons sandstone (Permian) discovery of the west flank of the Denver basin were the most significant successes. The Piceance basin of western Colorado appeared to be developing into a significant gas province.

Continuation of a moderately high level of drilling activity is contemplated during 1957 with increasing emphasis being placed on the pre-Cretaceous objectives in western Nebraska and the eastern half of Colorado. Exploratory successes in the Paradox and Piceance basins are expected to encourage sustained activity in western Colorado.

The majority of 1957 leasing activity centered in southeastern Colorado along the Las Animas arch.