Tennessee had 227 oil and gas tests reported in 1979, up 2.2% from 1978. Exploratory wells (106) were down 29.4%. Development drilling increased 40.5%. The success rate for exploratory wells was 70.7%, and for development wells, 87.6%. Tests were drilled in 19 counties; Scott, Morgan, and Fentress Counties were the most active. Total footage for all tests was 353,731, of which 160,181 ft was exploratory. Mississippian carbonates continued as the most important exploratory objective; most completions were made in the Ft. Payne and Monteagle limestones. Crude oil production for 1979 was 613,671 bbl, an increase of 3.5% from 1978. Marketed natural gas was 941,049 Mcf, an increase of 101.2% over 1978.

Illinois had 1,131 oil and gas tests in 1979, up 3.4% from 1978. Exploratory tests numbered 235, down 11.3%, and 21.7% were successful. Total footage drilled, including service wells, was 3,001,186, down 2.7% from 1978. Burnt Prairie Southwest in White County appears to be the best of the 1979 discoveries. Production is from the Aux Vases Sandstone and the Ohara, Spar Mountain, and McClosky pay zones in the Ste. Genevieve Formation. For the 21 wells reported in 1979, initial production averaged 91 BOPD. Tests that bottomed in the Salem Limestone and underlying Ullin Limestone declined from 308 in 1978 to 237 in 1979; they accounted for 21 of the total tests and for 15 of the 51 successful exploratory tests. The deepest test reported in Illinois in 1979 was a 5,645-ft Silurian deeper p ol test in Calhoun Consolidated field, Richland County. No shows were reported below the Salem, which, at about 3,750 ft, is the deepest pay in the field. Crude oil production in Illinois in 1979 was 21,793,000 bbl, down 6.7% from 1978.

Indiana had 489 oil and gas tests in 1979, down 26.9% from 1978. Drilling activity has been concentrated in the area of Gibson, Knox, and Pike Counties. There were 184 exploratory tests (down 31.3%), of which 22.8% were successful. Exploratory successes included 3 new-field discoveries and 25 new-pool discoveries. Of the 42 exploratory successes, 1 was in Devonian carbonate and 1 in Pennsylvanian sandstone; the others were in Mississippian carbonates or sandstones. Deeper Mississippian strata continued as targets of exploratory activity. A well in Griffin Consolidated field initialled for 130 BOPD from an interval of 4,045 to 4,498 ft in Middle Mississippian rocks; it is an extension of what is called Ft. Payne on the Illinois side of the Wabash River. In 1980, drilling is expected to concentrate on deeper strata in old fields, some rank wildcat drilling, and redrilling of poor reservoirs that may have become economic with the increased price of oil. Crude oil production in Indiana in 1979 was an estimated 4,733,000 bbl, a slight increase from 1978.

In Kentucky, 877 oil and gas tests were drilled in 1979, down 5.1% from 1978. The 332 exploratory tests, down from 351 in 1978, resulted in 42 oil wells and 38 gas wells, a success rate of 24.1%. Development wells were 60.7% successful and resulted in 234 oil wells and 97 gas wells. Among the exploratory successes in western Kentucky was a new-field discovery in Webster County that flowed 221 BOPD from the McClosky. Clear Creek production (Devonian) was discovered in Deanefield field, Ohio County. Leasing and drilling in Muhlenberg County have increased appreciably. In central Kentucky, drilling increased greatly in Clinton and Cumberland Counties; several new areas of Ordovician production were discovered. In eastern Kentucky, the main interest has been in exploration of Big Lime pro uction. Seismic exploration has increased in eastern Kentucky, and at least 2 deep tests are scheduled in the Rome trough. Prospects for 1980 are for a banner year for all areas of the state. Crude oil production in Kentucky in 1979 was 5,513,688 bbl, down 3.4% from 1978. Gas production was 59,519,590 Mcf, down 14.2%.