Tennessee had 351 oil and gas tests reported in 1980, up 54.6% from 1979. Exploratory wells (196) were up 84.9%. Development drilling increased 28.1%. Morgan, Scott, Fentress, and Overton counties accounted for more than 70% of the permits issued in 1980. Carbonates of Mississippian age continued to be the most important objectives in exploratory drilling. Almost all of Tennessee's oil and gas production is found in stratigraphic traps in the Fort Payne and Monteagle limestones. Leasing was very active in 1980. An estimated 5.5 million acres are under lease. Crude oil production in 1980 was 743,000 barrels, up 21.1% from 1979. Marketed natural gas in 1980 was 1,248,000 thousand cubic feet, and increase of 32.6% from 1979.

Illinois had 1,980 oil and gas tests in 1980, up 75% from 1979. Exploratory tests numbered 451, up 92%, and were 18.8% successful. New field wildcats were 5.1% successful. Deeper pool tests were 25% successful. Of the 6 new field discoveries in 1980, 2 produce from Pennsylvanian rocks, 3 from Mississippian (Valmeyeran) and 1 from Devonian. Of the 36 new pools discovered, 31 produce from Valmeyeran, and 5 produce from Devonian. In Clay City Consolidated field, in the vicinity of the town of Clay City in Clay County, many excellent wells were completed, mostly in the Valmeyeran. This oil is stratigraphically trapped in a syncline. After years of being dominated by the anticlinal theory, much future exploration in Illinois probably will be directed toward the search of such pure stratigr phic traps. Drilling activity in Illinois in 1981 is expected to match or exceed the pace set in 1980. Crude oil production in Illinois in 1980 was 22,702,000 barrels, up 4.2% from 1979.

Indiana had 725 oil and gas tests in 1980, up 48.3% from 1979. Exploratory wells increased from 184 in 1979 to 322 in 1980 and were 28% successful. New field wildcats were 8.8% successful. Of a total of 90 exploratory successes, 9 were new fields, 63 were new pools, and 18 were extensions to pools. Three new field discoveries, 1 new pool discovery, and 1 extension were gas wells; the rest were oil wells. Chesterian and Valmeyeran (Mississippian) rocks were the chief targets of exploration. Gibson, Posey, and Knox counties accounted for 73% of the exploratory successes. Average depth of the successful exploratory wells was 2,187 ft, 406 ft deeper than the average in 1979. The Trenton field of east-central Indiana, discovered in 1886, received renewed interest in 1980. The increased dri ling activity in Indiana in 1980 is expected to continue in 1981. Estimated crude oil production in Indiana in 1980 was 4,520,000 barrels, a decline of 200,000 barrels from 1979.

In Kentucky, 1,244 oil and gas tests were drilled in 1980, up 41.8% from 1979. The 437 exploratory tests, up from 332 in 1979, resulted in 54 oil wells, 31 gas wells, and 3 combination oil and gas wells, a success rate of 20.1%. Exploratory successes included 18 new pool wildcat discoveries, 6 deeper pools, 5 shallower pools, and 59 extensions. No new fields were discovered. Development wells were 60.8% successful and included 391 oil wells, 92 gas wells, and 8 combination oil and gas wells. Oil production in Kentucky in 1980 was 5,945,666 barrels, an increase of 7.8% from 1979. Gas production, 96% of which is from eastern Kentucky, was 58,274,375 thousand cubic feet, virtually the same as in 1979. In 1980, the number of permits issued reached an all-time high of 4,132, 40% of which w re in the south-central portion of the state. Drilling activity in 1981 should exceed that of 1980.