Overall exploratory activity decreased 9% from 1980 totals. 27 new onshore Miocene reservoirs found: however, there were no new fields discovered. 272 Oligocene discoveries made onshore. Eocene discoveries totaled 168, down 23% from 1980. Activity in the Cretaceous trend was up 56% in 1981 with 148 discoveries made. There were 2 Jurassic discoveries. Exploration activity in the south Texas offshore resulted in 13 new reservoirs, 5 of which were new fields.--Modified journal abstract.