In Tennessee, drilling activity declined in 1984. The number of permits issued was down from 822 in 1983 to 670 in 1984. Scott, Morgan, Overton, and Fentress Counties on the Cumberland Plateau accounted for almost 75% of the permits; Clay and Pickett Counties on the Eastern Highland rim had almost 100 between them; Campbell and Claiborne Counties on the Pine Mountain block accounted for 31. The oolitic zones of the Mississippian Monteagle in the plateau and the Pine Mountain areas, and the Ordovician Nashville (Trenton), Stones River, and Knox Groups in Clay and Pickett Counties were the principal targets. Because of a good response to regulations, the number of wells classified was up from 922 in 1983 to 1,045 in 1984. The 1984 classifications showed 408 development well (119 oil, 184 gas, 33 oil and gas, 72 dry), 529 wildcats (82 oil, 201 gas, 9 oil and gas, 237 dry), and 108 abandoned locations. Oil production in 1984 was about 937,500 bbl, compared to 1,052,000 in 1983. Gas production, which has increased steadily since 1981, was slightly more than 5 bcf in 1984.

In Illinois, the Geological Survey processed reports on 2,762 oil and gas tests in 1984, 3.5% more than in 1983. These included 661 exploratory wells (up 3.2%) and 2,101 development wells (up 3.6%). Exploratory wells were 15% successful; development wells were 72.0% successful. Exploratory successes included 10 field discoveries (all small) and 18 deeper pay discoveries. The deepest pay discovery was a well in Mayberry field, Wayne County, that had an initial production of 85 BOPD from the Dutch Creek (Devonian) between 5,300 and 5,322 ft. Many excellent wells continued to be completed; 135 with initial productions of 100 BOPD or more were reported in 1984. The biggest was a 900-BOPD Ullin (Mississippian) well in White County. Forty of the tests reported in 1984 went to TD 4,500 ft or deeper. The deepest, all Ordovician, were a 6,000-ft Knox test in Effingham County, a 6,300-ft Platteville test in Franklin County, and, in Williamson County, a 7,250-ft Trenton test and a 7,400-ft Knox test. A projected 8,300-ft Knox test is drilling in Williamson County. Drilling activity is expected to decline slightly in 1985. Crude oil production in 1984 was 28.9 million bbl, down slightly from 1983.

In Indiana, 980 holes (405 exploratory, 513 development, and 62 service) were drilled in 1984, 52 less than in 1983. Exploratory wells were 19.8% successful (72 oil, 8 gas). Development wells were 68.2% successful (337 oil, 13 gas). Total footage drilled for all wells was 1,790,217 ft. Most drilling was in traditional areas of activity, but some exploration shifted eastward to the marginal flank of the Illinois basin, where testing of the Harrodsburg Limestone (Mississippian) in Spencer County resulted in a number of successes. Interest in the Harrodsburg in this area was stimulated by the completion in 1982 of the first Harrodsburg producer in the area since 1953. Rumors of the discovery in December 1984 of the first production in Indiana from Lower Devonian carbonate rocks were conf rmed in February 1985. These rocks underlie almost all of the shallower reservoirs of southwestern Indiana and have had virtually no testing. The discovery well, in Spencer County, had an initial potential of 120 BOPD from the interval in the Lower Devonian between 2,488 and 2,507 ft. Exploration and development drilling in Indiana is expected to continue at a healthy rate in 1985. Oil production in 1984 was 5,394,147 bbl, virtually unchanged from 1983.

In Kentucky, drilling activity declined significantly in 1984. Permits issued were down from 6,779 in 1983 to 6,258 in 1984, and 2,671 of those issued in 1983 were allowed to expire without drilling. Late reporting of 1983 completions and improved reporting of 1984 completions resulted in a statistical increase of 129% in exploratory tests and 151% in development wells reported. Of a total of 1,994 exploratory tests in 1984, 559 (28%) were successful. The intense drilling activity of the past few years in the Cumberland saddle has diminished. Increased drilling for gas in eastern Kentucky resulted in a number of gas producers in the "Big Lime" (Mississippian) in Whitley County and in the "Big Lime" and Devonian shale of Leslie County, and in the discovery of both oil and gas in Middle and Lower Ordovician beds in Clay County. In south-central Kentucky, the main emphasis has been on extensions of oil production from the "Corniferous" (Clear Creek) in Warren County. The most significant developments in western Kentucky occurred in Henderson County, where numerous wells have been completed producing from various zones in the middle Mississippian. Kentucky produced 7,787,513 bbl of oil in 1984, 1.3% less than in 1983.