The mid-eastern states are the southern half of the northeastern United States and include Maryland, Ohio, Pennsylvania, Virginia, and West Virginia. Exploratory activity in this region decreased slightly during 1989 as 178 exploratory completions were reported to state agencies, down 2.7% from 1988. Exploratory targets ranged in age from Triassic (in Virginia) to Cambrian (in Ohio). Overall drilling activity decreased as completions reported decreased 4.7% and footage drilled decreased 2.0%. As usual, drilling was relatively shallow, with average well depths ranging from 3681 ft in Pennsylvania to 4475 ft in Virginia, and very successful, with success rates ranging from 88% in Ohio to 96% in Pennsylvania. Gas production increased 4.8% in 4 of the states (data are unavailable in West Virginia). Oil production, down in all of the states, was 11.8% for the region.

There were no wells drilled for exploration or development of oil or gas in Maryland during 1989. However, data were released on 2 tight holes drilled during 1988, both unsuccessful Benson sandstone tests near Accident field. Natural gas production from the 3 Maryland fields increased 17%. All production is from the Devonian Huntersville-Oriskany interval. A consultant was hired by the state to consider comments from 20 interested parties while compiling a comprehensive set of oil and gas regulations which should be in place by summer 1990.

Drilling activity in Ohio continued to decline, down 9.2% from 1988. The number of wells drilled was the lowest total since 1975. Wells continue to be successful, however, with a completion rate of 87.9%, and relatively shallow, with an average depth of 4115 ft. Drilling ranged from the Pennsylvanian Cow Run sandstone to the Cambrian Trempealeau Dolomite. The Silurian Clinton sandstone, however, remained as the prime target, with 68% of all wells drilled to this reservoir. Other targets included the Ohio Shale, Rose Run Sandstone, Trempealeau Dolomite, and Berea Sandstone. Exploratory wells equaled the 1988 total, and although Rose Run and Trempealeau wells again dominated exploratory activity, success rates for these wells were low. A core hole being drilled as a stratigraphi test discovered a new basin filled with 3500-5000 ft of Cambrian sandstone above crystalline basement. The hydrocarbon potential of this newly discovered basin has yet to be determined. Oil production decreased 12.7%, and gas production decreased 4.2%.

Drilling activity as reported in Pennsylvania during 1989 decreased by 14%, as did the footage drilled. Exploratory activity decreased slightly by 3%, yet footage drilled increased by 17%. Seismic activity decreased 50%. Development drilling also declined by 13%, and development drilling footage decreased accordingly by 15%. There was a 22% decrease in deep drilling (528 wells in 1989 compared to 674 in 1988); however, deep drilling still represents 35% of the total drilling activity. As in past years, deep drilling was concentrated on continued exploration and development of Lower Silurian Medina fields in northwestern Pennsylvania. Shallow drilling activity decreased 9% and, again in 1989, was dominated by Upper Devonian gas fields throughout central and western Pennsylvania Significant exploratory tests were reported in 15 counties in western and northcentral Pennsylvania, with targets ranging from the Upper Devonian Lock Haven Formation to the Upper Cambrian Gatesburg Formation. Oil production decreased 7.3%, and natural gas production increased 14.7%.

Drilling activity in Virginia was slightly lower during 1989 with 40 new wells drilled, a decrease of 11.1% from the 1988 total of 45. Of the 40 new wells, 36 were completed as producers and only 4 were dry holes, a success rate of 90%. Total footage drilled decreased 16.2%. Exploratory well completions dropped from 14 in 1988 to only 3 in 1989 (down 78.6%), and only 1 was successful. This single exploratory success produced gas from a Pennsylvanian coal, whereas the 35 development

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wells were completed in reservoirs ranging from Pennsylvanian coal to Devonian shale. Production of natural gas totaled 17,935,376 mcf, a 4.0% decrease from 1988. Crude oil production decreased during 1989 to 21,271 bbl, a drop of 14.8% from 1988. Based on current projections, drilling activity should increase in 1990 as at least 1 new coalbed methane project is initiated and several companies increase their development programs.

Exploratory completions increased 36.4% in West Virginia, and exploratory footage was up 33.8%. Two new fields and 9 new pools were discovered. Total well completions, including workovers, were up 9.1%. The main exploration programs consisted of scattered tests to the Lower Devonian Oriskany Sandstone and deeper than normal tests to the Devonian shales in several southwestern counties. At least 6 slant holes were drilled through the shale section in that area. Deeper drilling decreased 25.8%. All but 2 of the deep wells were tests of the Middle Devonian Huntersville Chert or Lower Devonian Oriskany Sandstone, and only 35.5% of the deep wells were successful. Seismic activity increased 72.3% and was concentrated in 4 eastern counties adjacent to the Allegheny front. Other lines were shot in areas of Devonian shale exploration. Oil production decreased 12.8%; gas production figures are not available.