ABSTRACT

Morrow County, Ohio has a long and well documented Copper Ridge ("Trempealeau") erosional remnant exploration and hydrocarbon production history starting in the early 1960's and continuing sporadically to the present. Paleotopographic reconstruction, isopach mapping and seismic surveys are the most common and effective methods used to pinpoint drillsites on the erosional remnants.

The recently drilled Columbus Oilfield Jagger #1 well in Congress Township has discovered a commercial quantity of oil and gas with reserves large enough to warrant further exploration in the area. The reservoir produces from depositionaly controlled porosity in the Copper Ridge dolomite ("Trempealeau"). It is situated on a basement fault block-supported anticline with relatively thick "Glenwood" and Trenton to Trempealeau isopach values. This reservoir is fundamentally different than the classic erosional remnants of the area and challenges "rule of thumb" exploration criteria.

Future exploration of the area requires detailed mapping of porosity zones the Knox unconformity. Seismic data is used to locate individual, positive, basement fault-blocks and the associated Trempealeau high. Seismic anomalies must be carefully scrutinized for false positives caused by localized shale velocity anomalies.