RESERVOIR CHARACTERIZATION AND CO2 EOR MODELING SIMULATION OF THE SILURIAN “CLINTON” SANDSTONE IN THE EAST CANTON OIL FIELD, OHIO

The Ohio Geological Survey has conducted a reservoir characterization and simulation of the Silurian “Clinton” sandstone in the East Canton oil field, in eastern Ohio. The primary objective was to evaluate potential for carbon dioxide-enhanced oil recovery (CO₂-EOR). The East Canton oil field has produced 95 million barrels of oil from 3,100 wells on 175,000 acres. The field is contains over one billion barrels of original oil-in-place. “Clinton” gross thickness is 110 ft; net thickness is 50 to 70 ft. Development is based on primary depletion using hydraulically fractured wells on 40 ac spacing. The reservoir contains matrix porosity of about 7 to 14% and matrix permeability of 0.1 to 0.6 millidarcies. Natural fractures may enhance permeability by as much as 10 times. Initial reservoir pressure ranges from 1,500 to 2,400 psi; existing pressure is 300 psi. The field has not been water flooded.

After a regional geologic study, a detailed local stratigraphic study of a 4-by-4-mile area of interest was developed. Over 250 wire-line logs, mostly gamma-ray/neutron density logs, were analyzed and used to create detailed maps. The five porous sandstone units within this 5,000-ft-deep reservoir were correlated. Structure, lineament, net and gross sandstone, isopach, porosity, permeability, and production maps were constructed.

Fekete Associates Inc. constructed a CO₂-EOR simulation model of the “Clinton” reservoir in the area of interest to design a CO₂ pilot flood by examining natural and hydraulic fractures and well spacing, and by evaluating a “Huff-n-Puff” test conducted in the area of interest. The reservoir model incorporated detailed mapping, production, and fracture analyses, as well as “Clinton” fluid properties and relative permeability data from published reports.

During modeling, a history match attempted to confirm the understanding of the impact of natural and hydraulic fractures and also attempted to quantify properties controlling fracture/matrix fluid exchange. The “Huff-n-Puff” provided insight into CO₂ movement and the impact of oil swelling. Simulation of CO₂ pilot flooding evaluated operational parameters impacting flood performance, such as well spacing and pattern configuration. The project would benefit from additional properties testing and more numerical simulation.