Exploratory drilling in the shallow-sand territory of western Pennsylvania (Upper Devonian or higher) during 1949 led to the discovery of 3 new gas fields. One of these may be proved significant in size. No new oil pools were discovered. The total number of shallow wells drilled, exclusive of those drilled in connection with underground gas storage and secondary-recovery oil operations, was 17 per cent less than in 1948. In the Pennsylvania part of the Bradford oil field, which continued to be the most active area, 1,100 new wells were completed, as compared with 2,070 in 1948. About half of these were water-intake wells. The Bradford field accounted for 79 per cent of the total oil production in Pennsylvania during 1949. The average daily oil production in the state in 1 49 was 31,347 barrels, as compared with 35,206 barrels in 1948.

Twenty-seven new wells were completed to the deeper formations (Onondaga or deeper) as compared with 30 in 1948. Of these, one was drilled for gas storage purposes. Of the remainder, 16 were gas wells and 10 were dry holes. One may lead to the development of a new Onondaga chert gas field. The greatest activity centered in the East Fork-Wharton Oriskany sand gas pool of north-central Pennsylvania where 13 wells were completed, whose initial open-flow capacities ranged from 165 thousand to 22 million cubic feet per day. The W. R. Barton Estate well No. 8 in the South Summit field of Fayette County, drilled to the depth total of 10,312 feet, is now the deepest in Pennsylvania and the Appalachian province, and also has the distinction of being the deepest well in the world to be drilled ntirely with cable tools.

A significant discovery in the Oriskany sandstone was made in Leidy Township, Clinton County, in north-central Pennsylvania shortly after the close of the year. A wildcat well on the Wellsboro anticline, 10 miles southeast of the East Fork-Wharton pool, encountered gas under a reservoir pressure of 4,200 pounds per square inch. The initial open-flow was estimated at 10-15 million cubic feet per day. The discovery has focused attention on a large area that has not yet been explored.