Total oil production in Illinois, Indiana, Kentucky, and Tennessee in 1973 was 45 million bbl, down 11.9% from 1972. Tennessee had a very slight increase; all the other states had decreases. Gas production in Kentucky was 69.7 Bcf in 1973, down 7%. Gas production in the other states is not significant.

A total of 1,524 oil and gas tests was drilled in 1973, down 11.4% from 1972. Exploratory tests totaled 565, only 4 tests fewer than in 1972. Of these, 85 (15%) were successful.

Tennessee had 98 oil and gas tests in 1973, up 4.6% from 1972. The number of exploratory tests was down 1.5%; development wells were up 18.5%. Total footage for all tests was 141,950, of which 97,282 ft was exploratory. Much of the activity was concentrated in Scott, Morgan, and Fentress Counties. Three oil fields, 4 gas fields, 2 oil pools, and 5 extensions (2 oil, 3 gas) were discovered in 1973. A dry 4,875-ft basement test was drilled in Macon County. A basement test is drilling in DeKalb County, and a projected Copper Ridge test in Smith County is shut down at 3,380 ft. Leasing activity increased markedly on the east flank of the Nashville dome. Primary deep objectives in Tennessee are probably the lower Knox and pre-Knox Cambrian sedimentary rocks, and shallower objectives are th upper Knox, Trenton, and Mississippian carbonate rocks. Crude-oil production in Tennessee in 1973 was 201,000 bbl, up 1.5%.

Illinois had 556 oil and gas tests in 1973, down 7.8% from 1972. Exploratory tests were up 29.8%, from 151 in 1972 to 196 in 1973. Development wells were down 20.4%. Total footage drilled in oil and gas tests and service wells was 1,446,083, up 3.3% from 1972. Three oil fields, 11 extensions, 4 new-pool wildcats, and 7 new-pay zones in existing fields were discovered. The main focus of exploration was in southwestern Illinois in the Marion and Washington Counties area. Silurian reef production was the principal objective there, but several "Trenton" tests also were drilled. Nashville field in Washington County was the most significant discovery in 1973. Production is from a Silurian reef. Reserves in the field are estimated at more than 1 million bbl. Silurian reefs and Cambrian-Ordov cian strata are expected to be targets of exploration in 1974. Crude-oil production in Illinois in 1973 was 30,669,000 bbl, down 12.1%.

Indiana had 139 exploratory wells (8 more than in 1972) and 100 development wells in 1973. Exploratory tests resulted in 14 (10.1%) successes. Seven oil fields, 3 gas fields, and 6 oil pools were discovered (2 of the new fields resulted from workovers, not included in AAPG-CSD statistics). The discovery well of Westphalia South, one of the most promising of the new fields, was completed in December for an initial daily production of 384 bbl. Production is from the Ste. Genevieve Limestone. The trap appears to be stratigraphic rather than structural. Exploratory activity was concentrated in the belt of known Silurian reefs. Three counties within this area (Daviess, Greene, and Knox) accounted for more than half of the exploratory tests in the state. Exploration in 1974 is expected to f llow the trend of recent years. Silurian reefs, Knox erosional remnants at the Lower Ordovician-Middle Ordovician unconformity in eastern Indiana, and the Middle Ordovician (Trenton) of northern Indiana are expected to be targets. Estimated production in Indiana in 1973 was 5,400,000 bbl, down 730,000 bbl from 1972.

A total of 631 oil and gas tests was drilled in Kentucky in 1973. Of 164 exploratory tests drilled, 34 were successful (20.7%). The exploratory successes included 8 fields, 20 deeper or shallower pools, and 6 extensions. Intensive leasing in many parts of Kentucky reflected an interest in deeper Paleozoic strata. Geophysical activity may have reached an all-time high in all parts of the Commonwealth. In Johnson County, a Precambrian test reached a new depth record of 14,566 ft. Other deep wells in 1973 included a 10,000-ft Tomstown test and a 5,877-ft Knox test, both in Johnson County, and a 4,584-ft Copper Ridge test in Morgan County. A Knox test was nearing completion in Logan County. Crude-oil production in Kentucky in 1973 was 8,686,854 bbl, down about 1 million bbl from 1972. Gas production was 69,737,007 Mcf, down about 5 Bcf.