The exploration for and development of Middle Silurian Niagaran reefs dominated Michigan's oil and gas industry activity for the 13th year in a row. Heaviest drilling was concentrated in the northern part of the Southern Peninsula along the reef trend. Reef exploration also continued at a high pace in south-central and southeastern Michigan. Overall, well completions in 1981 broke a 20-year record.

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.

Exploration and development footage figures, derived from Michigan Geological Survey Division records, amounted to 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. An additional 135,686 ft, mainly gas storage facility wells, is credited to 1981.

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 located along the northern reef trend accounted for approximately 72% of the oil and 83% of the gas produced in 1981.