INTEGRATED CHARACTERIZATION AND MODELING WORKFLOWS FOR A DEPLETED RESERVOIR IN THE TRENTON-BLACK RIVER PLAY, SOUTHERN MICHIGAN, PART 2: STATIC AND DYNAMIC MODELING

The Trenton-Black River play in Michigan has produced significant amounts of oil since the 1960’s, reaching over 170 million barrels produced by the 1980’s. The United States Geological Survey predicts that there are over 700 million barrels of unrecovered oil in the play, which makes it an attractive target for both primary recovery in new fields and enhanced oil recovery (EOR) in existing fields. As part of a US Department of Energy funded project to assess the viability of CO2-EOR in the Michigan Basin, the Lee 26 Field, containing four production wells, was analyzed first using standard seismic and well log-based reservoir characterization workflows, and then modeled using static and dynamic reservoir modeling workflows to determine the effectiveness of enhanced oil recovery methods. Part 2 of this two-part talk reviews the modeling workflows used to plan EOR operations.

The primary driver of production in the Trenton-Black River play is secondary porosity and permeability due to fractures and vugs developed by strike-slip faults that serve as a fluid conduit for magnesium-rich fluids that contribute to dolomitization. Reservoir characterization results identified zones with high secondary porosity and permeability. Distribution of facies and petrophysical properties were constrained based on proximity to faults identified in seismic. Facies selections were made based on a review of the mud logs in each well and verified by a porosity cutoff, with greater than 5% porosity being dolomite facies and less than 5% being limestone facies. While core data was not available in the Lee Field, the Timur (1968) correlation was used to develop the permeability distribution based on effective porosity and irreducible water saturations from the nearby Albion-Scipio Field.

Two superimposed, fully heterogeneous porosity and permeability distributions – representing the matrix and fractures/vug media – were generated by combining log-derived porosity and permeability measurements and pressure transient analysis results. A high-quality match to field production history was obtained using the commercial black-oil simulator CMG-IMEX. Forecasting simulations have indicated appreciable incremental recovery resulting from CO2-EOR.