Exploratory activity in Washington declined. One exploratory well in Oregon was drilled during the year. Exploratory drilling in California increased moderately over 1972. Most of the increase was in wells drilled primarily to find gas. The number of wells drilled in California was less than in any year since 1942. New oil and gas discoveries reversed the trend of the past several years and showed a significant increase in the volume of reserves discovered. There were 5 significant oil discoveries, but no new oil-field discoveries, and 9 significant gas discoveries made in California. Exploration activity was high in the Sacramento Valley and in the Outer Basins area south of the Santa Barbara Channel Islands. A campaign of deep drilling was initiated in California which ill continue in 1974.

Geothermal exploration continued in northern California. One geothermal test was drilled in south-central Oregon. The Geysers became the world's largest producer of geothermal power. Testing continued in the Imperial Valley to determine if highly saline and lower temperature reservoir fluids can become a commercial source of power.