As in the past few years, Michigan again registered a decline in exploration and development activity. There were 435 completions (excluding 28 gas in-put wells) as compared with 509 completions for 1955. Of the 1956 total, 270 were development wells and 165 were exploratory wells. The development wells included 195 producers and 75 dry holes. Exploratory wells included 13 producers and 152 dry holes. Reworking of older field wells and the drilling of development wells accounted for the discovery of 6 new pays.

Total drilled footage of all oil and gas tests (excluding gas in-put wells) was 1,281,657 ft., classified as: exploratory, 461,359 ft.; and development, 820,298 ft. In 1955 the footage drilled was 1,517,951 ft.

Oil produced during the year was 10,737,697 bbls. and gas 8,840,933 MCF. In 1955, 11,265,842 bbls. of oil and 6,787,697 MCF of gas were produced.

Undeveloped acreage under lease for eleven major companies operating in Michigan on December 31, 1956, was 752,051 acres. The same companies had 817,361 undeveloped acres under lease on December 31, 1955.

Only 13 core-test permits were issued for the year. Five of these prospective tests were not drilled. One hundred fourteen core permits were issued and drilled in 1955.

One seismograph company did minor work in the Southern district. Some combination gravity and radiation work was reported in the Southwestern district.