Permeability Studies of Pennsylvania Oil Sands

Abstract

The permeability of an oil or gas sand is its capacity for transmittingfluids, either liquids or gases, under pressure. The permeability of a sanddepends upon the size and shape of the openings in it and the extent to whichthese communicate with one another, as well as upon the ratio of their volumeto the total volume of the sand. The apparatus employed and the method of procedure used by the authors inconducting the permeability tests have been described in a previouspublication. 1 For the tests described here 72-in. cubes were used. They wereset in the lower end of a 1-in. union, inserted in a square hole cut in a hardrubber stopper which fitted into the lower end of the union. In the tests withair, volumes were measured with a wet American gas meter of 100 cu. ft.capacity. In those with water, distilled water at room temperature wasemployed, unless otherwise noted. Description Of Sands Tested The tests described in this paper were performed upon 18 samples representingtypical oil and gas sands from 7 localities in northwestern Pennsylvania. Forpurposes of identification, the cores from which the samples came have beendesignated by capital letters, the sequence of the samples in the cores bynumerals, and the individual cubes by small letters. All cubes from the samesamples came from adjacent portions parallel to the bedding. Core A of the Bradford sand came from the north central part of the Bradfordfield, from an area where water-flooding operations have proved highlysuccessful. Core B of the same sand was obtained from the southern part of thefield. This core contained a so-called "loose streak," 7.5 ft. thick, in the middle portion of which B2 is a representative sample. The "loosestreak" has given trouble in water-flooding but responded favorably to anair-drive, using a pressure of 300 lb. The natural production was increasedapproximately five times over a period of three years in which the air-drivewas in operation.