Knox Unconformity Production from Morrow County, Ohio, with Emphasis on the South Woodbury Pool, Peru Township

Zody, Steven P.
Zody Geoscience, Wooster, OH

Greater Morrow County has proven to be Ohio’s most prolific Knox play. Erosional remnants of the Upper Cambrian Knox dolomite have been outstanding oil producing reservoirs for over 40 years in Morrow County, Ohio. These reservoirs developed beneath the Knox unconformity which resulted in a sharp erosional contact between the Knox dolomite and the overlying Middle Ordovician Wells Creek Formation. Over 200 paleotopographic pools, generally covering only 5 to 150 acres, have been discovered in the region. Karst processes and the resultant solution enhanced porosity and permeability are responsible for the development of many high quality reservoirs capable of yielding over 100,000 barrels of oil per well. Several exceptional reservoirs have produced in excess of 500,000 barrels of oil per well. Peak oil production of 35,000 barrels per day was achieved during the height of development in 1964. The play in this region has produced an estimated 45 million barrels of oil from roughly 1000 producing wells.

South Woodbury Pool in northern Peru Township has produced an estimated 3,500,000 barrels of oil. Several wells drilled during the initial development in the early 1960’s are still actively producing. The field consists of a loosely coalesced series of remnants that comprise a long, linear (relatively large for this play) ridge with over 100 feet of relief. As is commonly the case in this play, the overlying Wells Creek Formation thins or is not present over the crest of the features.

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