Exploration resulted in 69 new discoveries, 84% of which were new Niagaran reef reservoirs. A gas discovery in the Prairie du Chien Group, at a depth greater than 10,000 ft, generated a great deal of excitement in the central basin deep play. 1,766,593 ft exploratory and 1,255,759 ft development compared with 1,375,993 ft exploratory and 1,468,038 ft development drilled in 1980. Oil and gas production declined slightly in 1981. Preliminary figures show that Michigan produced 32,664,000 bbl of oil (including condensate) and 152,593 mcf of gas. Niagaran reef reservoirs accounted for approximately 72% of the oil and 83% of the gas.--Modified journal abstract.