Niagaran reef exploration continued to dominate the scene for the third straight year. Reef exploration was concentrated mainly in the Northern District, in Ingham County and nearby areas and in St. Clair County. Of the 41 new discoveries (including new pools), scattered around the basin, most were found in Grand Traverse, Kalkaska, and Otsego Counties in the Northern District, and in Ingham County in the southern part of the basin. In the Northern District 18 new fields were discovered; in Ingham County, 4; and in St. Clair County, 2.

Exploratory and development footage, figured from CSD printouts, amounted to about 1,244,976 ft in 1971 compared with 1,073,765 ft in 1970. Of the total, 692,660 ft is credited to exploratory wells and 554,968 ft to development well drilling. Geological Survey records show an additional 180,418 ft drilled in connection with gas storage reservoirs and other types of service wells.

New policies and rules relating to drilling on state-owned lands and leasing of state-owned lands may affect exploration and development drilling in northern Michigan.

Preliminary oil production figures for 1971 indicate a small increase in the yearly total: 11,893,411 bbl compared with 11,693,488 bbl in 1970. Preliminary gas production figures show a decrease in production for 1971: 25,930,622 Mcf compared with 39,252,013 Mcf in 1970. The small increase in oil is attributed to new reef developments. Most new reef gas fields have been shut in pending marketing facilities. When these fields go on production, gas figures will show a substantial increase. The Albion-Scipio trend oil pools produced about 40% of the oil and 43% of the gas in 1971.