Abstract
The Mayfield pool, the most productive of the Newburg-sand gas pools in Ohio, is in northeastern Cuyahoga County. The rocks that have been tested by drilling range in age from Upper Ordovician to Upper Devonian. Rocks that crop out in the area are Upper Devonian and Mississippian in age. They are extensively covered by Pleistocene and Recent deposits. Gas and a small amount of oil are produced from the Newburg sand (Middle Silurian) at an average depth of 2,875 feet, and from the so-called Oriskany sand (Lower Devonian) at a depth of 1,800 feet. The reservoir is of the structural type in the Oriskany sand and is of a combined structural and porosity type in the Newburg sand. The structure has not been completely outlined because of the cover of Pleistocene deposits at the surface and restrictions on drilling south and southwest of the pool. However, at the surface the structure appears to resemble a dome with limbs dipping about 0°18^prime. In the subsurface the structure appears to be a broad anticline trending northeast with a known closure of approximately 100 feet and with its southeast limb dipping 0°38^prime. Fifty-two tests, eleven of which were dry holes, have been drilled on the anticline. The total yield of gas, on January 1, 1949, has been nearly 14½ billion cubic feet from wells having a distribution ratio of 30 acres per well. The chances of obtaining oil or gas from deeper Ordovician and older strata are considered to be chief y dependent on the amount of closure in the structure in these deeper strata, and on the porosity of the rocks.
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