There were 100 fewer tests drilled in Colorado and western Nebraska in 1963 than in 1962. This was a decline of 8.8%. The over-all success ratio, however, remained nearly constant, increasing by 0.3% to 29.6%. Exploratory drilling in the Cambridge Arch area of Nebraska suffered a sharp decline. This was not reflected by the success ratio in the area which increased from 4.2% in 1962 to 11.5% in 1963.

In Nebraska, oil and gas production declined from 30,703,000 bbls. and 24,200 MMCFC in 1962, to 26,912,000 bbls. and 15,470 MMCFG in 1963. This production decline was mirrored in Colorado by a decline from 42,477,000 bbls. and 173,230 MMCFG in 1962, to 37,859,700 bbls. and 159,650 MMCFG during 1963 (production figures approx.). Oil and gas reserves also declined during this period with considerably fewer reserves discovered than produced.

Several of the most active 1962 exploration plays either waned such as the Washington "D-J" and the Cambridge arch Pennsylvanian, or did not continue into 1963.

Exploration activity increased in eastern and southeastern Colorado. In northwestern Colorado, a good deal of interest has developed in the bituminous sands and oil shale deposits. Some rank wildcats were drilled in this part of the state but most success came from deeper drilling in established fields.

There was a 51% decrease in geophysical activity in Colorado and western Nebraska during 1963. This decrease was sharpest in Nebraska with a 77% decline and in southwestern Colorado with an 80% decline.

Exploratory activity in 1964 should continue at about the 1963 level with activity concentrated in northwest and eastern Colorado. Activity in the Cambridge Arch area of Nebraska should increase.