Eastern Section Meeting

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Evaluating the Silurian (Niagaran) Reefs in the Michigan Basin for carbon sequestration


The Silurian Niagaran Pinnacle Reef oil fields comprise a giant oil province with closely-spaced, highly geologically compartmentalized and laterally discontinuous oil and gas fields which have produced over 500 million barrels of oil and 2.9 trillion cubic feet of natural gas to date. Many of the fields are nearing or past the economic limitations of primary production mode and the considerable compartmentalization observed in many of the reefs make them a current target for CO2 Enhanced Oil Recovery projects. The fundamental assumption from previous work done on the Niagaran Reefs is that primary facies within the reservoirs have a first order control on pore types and reservoir quality. Therefore it is important to perform detailed facies analysis using rock core as well as evaluate the reliability of core to log calibration and correlation as proxy for identification of facies and stacking pattern relationships within the reefs. Understanding the relationships between petrophysical properties and the geological controls on the spatial distribution of these flow units are the fundamental inputs for 3D static earth models. The average primary recovery of these reservoirs is 26% and the potential value for modeling these reefs is that average secondary recovery is about 12.5% with only about 5% of the fields in the trend have undergone anything past primary. Our estimates for secondary recovery are at least 180 to 200 million additional bbls using CO2 EOR, but effective and efficient development of these reservoirs depends on high quality reservoir characterization.