Characterization of the Overton Pool: Upper Cambrian Copper Ridge Sandstone Play, Wayne County, Ohio

Thomas, John B.
Belden & Blake Corporation, North Canton, OH

The Overton Pool in Wayne County, Ohio was discovered in 1994 and lies along the present day Killbuck Creek drainage system believed to originate from the Cambridge Cross-Strike Structural Discontinuity. The producing reservoirs are the Copper Ridge (Trempealeau) sandstones that are present throughout north-central Wayne County. These sands, informally named the Copper Ridge “A” and “B” units were deposited possibly as tidal channels resulting from syndepositional activity along the Cambridge Arch. These units may be stacked, in which case they are separated by 25 to 30 feet of nonporous dolomite. The basal “B” unit is usually better developed with an average thickness of 20 feet and a maximum of 30 feet. The “A” unit has an average thickness of 6 feet and a maximum of 12 feet. Porosity is better developed in the “B” unit, probably a function of grain size and overall reservoir thickness. The configuration of the pool is defined by shallow mapping; however, high quality seismic data is key in defining the stratigraphic and structural details. Preserved Knox section, anomalous seismic amplitude, and waveform character can usually be observed. Copper Ridge sand outliers preserved away from the main pool tend to be more seismically definable but are often limited in reservoir size and areal extent.

Estimated ultimate recovery for the pool is 25+ BCFG and 1,300,000 BO with additional potential lying north and south of the main pool in preserved sand outliers. Because estimates of primary recovery are in the 15-20 percent range, the potential of an enhanced oil recovery project should be seriously considered.

AAPG Search and Discovery Article #90031©2004 AAPG Eastern Section Meeting, Columbus, Ohio, October 3-5, 2004