Abstract: Improved Reservoir Characterization of the Rose Run Sandstone on the East Randolph Field, Portage County, Ohio

Eugene L. Safley, John B. Thomas

The East Randolph Field, located in Randolph Township, Portage County, Ohio, produces oil and gas from the Cambrian Rose Run sandstone unit, a member of the Knox Supergroup. Field development and infill drilling opportunities illustrate the need for improved reservoir characterization of the hydrocarbon productive intervals. This reservoir study is conducted under the Department of Energy's Reservoir Management Program with professionals from BDM-Oklahoma and Belden & Blake Corporation.

Well log and core analyses were conducted to determine the reservoir distribution, the heterogeneity of the hydrocarbon producing intervals, and the effects of faulting and fracturing on well productivity. The Rose Run sandstones and interbedded dolomites were subdivided into three productive intervals. Cross sections were constructed for correlation of individual layers and identification of localized faulting. The geologic data was input into GeoGraphix software for construction of structure, net pay, production, and gas- and water-oil ratio maps.

Rotary sidewall cores and core plugs were analyzed to determine porosity, relative permeability, fluid saturation, and capillary pressures. Detailed core descriptions provided information on lithologies, depositional environments, diagenesis, and fracture density. Core to log relationships were used to refine geologic mapping.

Relationships between well production and reservoir parameters, such as structure, net sandstone thickness, and porosity were investigated. Volumetric calculations using the new geologic model increased original oil-in-place estimates to over 11 million stock tank barrels, more than doubling the original estimate. Reservoir simulation will be used to optimize locations of infill wells, and determine waterflood and/or pressure maintenance feasibility.

AAPG Search and Discovery Article #90950©1996 AAPG GCAGS 46th Annual Meeting, San Antonio, Texas