ABSTRACT: Porosity Trends of the Lower Ordovician Rose Run Sandstone in Adams and White Eyes Townships, Coshocton County, Ohio.

THOMAS, ROBERT B., and PATRICK J. BURNS, P. J. BURNS and Associates, Vienna, WV

The Rose Run Sandstone has become a primary target for exploration in eastern Ohio. Truncation of the Rose Run by the Post-Knox unconformity has created traps for hydrocarbon accumulation along the subcrop of the Sandstone. Identification of paleotopographic highs on the unconformity, either by seismic or subsurface geology, has been the primary focus of exploration to this point. Another important and often overlooked parameter when exploring for the Rose Run is that of reservoir quality.

In White Eyes and Adams Township of Coshocton County, Ohio, over 100 wells have been drilled through the Post-Knox Unconformity.

Complete, uneroded sections of the Rose Run have been electric logged in 63 wells. Average thickness for the main sand body of the Rose Run in the study area is 71 ft with a maximum of 88 ft and minimum of 56 ft. Porosity-feet (porosity times height) values were also calculated from the logs. The porosity-feet values ranged from 1.76 to 7.52 with an average of 4.32 porosity-feet. Average porosity for the Rose Run in the study area is 10.0%.

Overlaying the average porosity, porosity-feet, and isopach maps of the Rose Run onto the structure maps of the base of the Rose Run, indicates that the thick, high average porosity and high porosity-feet areas coincide with the structural lows on the base of the sand. Location of the high average porosity values, relative to the Rose Run Sandstone subcrop, also indicates the importance of primary sandstone porosity vs. secondary porosity developed at the time of the Post-Knox unconformity.

AAPG Search and Discovery Article #91013©1992 AAPG Eastern Section Meeting, Champaign, Illinois, September 20-22, 1992 (2009)