428 proceedings: geological society 



Problems of oil and gas accumulations in the Appalachian Region: M. 

 J. Munn. The oil and gas fields generally included within the Appa- 

 lachian region are situated in southern New York and the western parts 

 of Pennsylvania and West Virginia, the eastern parts of Ohio and Ken- 

 tucky, middle Tennessee, and northern and western Alabama. 



Structurally this part of the region is a broad flat geosyncline, roughly 

 coincident with the Appalachian Plateau. The deepest part of this 

 great structural basin is in the western part of West Virginia about 10 

 miles southwest of the corner of Pennsylvania. The general clip of the 

 rocks toward the center of this basin is broken by a series of minor, open, 

 irregular folds most of which trend northeast-southwest. The pitch 

 of the axis of this trough has not been determined thruout its length 

 but from the vicinity of Pittsburg southward to the center of the basin, 

 a distance of about 125 miles, it is approximately 2400 feet. At the center 

 of the basin the rocks consist of probably about 5000 feet of Devonian 

 sandstone and shale and thin beds of limestone, overlain by about 3000 

 feet of Carboniferous rocks of Mississippian, Pennsylvanian, and Per- 

 mian series, consisting of shale, sandstone, limestone, clay, and — in the 

 Pennsylvanian and Permian — many coal beds. The Permian rocks are 

 exposed over several hundred square miles in the center of the basin 

 and successively older formations outcrop in going from the axis of the 

 fold both east and west. 



The special points brought out in this paper were as follows: (1) By 

 far the largest number of oil and gas pools and also the largest pools are 

 grouped along the axis of this geosyncline, in areas where the rocks have 

 dips of less than 200 feet to the mile and rarely more than 75 feet to the 

 mile. (2) On the west side of the axis of this geosyncline oil pools pre- 

 dominate, though a number of large gas fields occur. East of this axis 

 only a few small oil fields have been found; this part of the region con- 

 taining many of the greatest gas fields yet discovered, in areas where 

 the rocks have in general a somewhat greater dip than in the oil fields 

 on the west side of the axis. (3) The oil and gas pools which occur near 

 the outer edges of this productive region farthest from the center of the 

 basin are found at relatively shallow depths in sandstones which show 

 considerable quantities of salt water closely associated with the oil. 

 When these sandstones are traced toward the center of the basin the vol- 

 ume of salt water appears to increase in each sandstone up to a certain 

 distance from the outcrop and depth from the surface. Beyond this. 

 down the dip of the beds, and therefore at greater depths from the sur- 

 face, the amount of salt water decreases, until, at the center of the basin 

 many of the sandstones that furnish salt water somewhere up the slopes 

 are found to contain no water when penetrated by the drill. (4) Many 

 large gas fields in flat-lying rocks near this axis show little or no water 

 in the producing sand in and immediately surrounding the gas field, the 

 sand being continuous over large areas and the closed pressure of the 

 gas ranging up to over 1000 pounds per square inch. 



One of the objects of the paper was to show that the general regional 

 conditions accompanying the occurrence of oil and gas in these fields 



