47th Annual AAPG-SPE Eastern Section Joint Meeting

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Residual Oil Zone EOR Potential in the Northern Pinnacle Niagaran Reef Trend


The primary goal of this study was to identify and evaluate the potential for a regionally pervasive residual oil zone (ROZ) in the Northern Pinnacle Niagaran Reef trend (NPRT) that could provide a viable enhanced oil recovery (EOR) play for operators and a CO2 sink for carbon capture, utilization, and storage (CCUS) projects. Data available for analysis included downhole well logs, core analyses, literature, maps, and input from ongoing regional geologic characterization. Structural complexity and well log data from ten reefs in Otsego County were used to evaluate the subregional petroleum systems evolution, leading to the following conclusions: • There is no evidence to support the presence of a regionally extensive ROZ in the NPRT. • Geographically isolated capillary pressure transition zones are present in all reefs, but they are unlikely to be in hydraulic communication with other reefs. • Changes in carbonate pore geometry with depth or other variables may impact interpreted water saturation (Sw) curves, generating expanded apparent transition zones where the water saturation remains constant. • Continuous bottom hole pressure (BHP) measurements collected before, during, and after CO2 injection in the Charlton 30-31 reef confirm hydraulic communication between the north and south reef pods on short time scales. • The combination of one-way analysis of variance and Tukey Grouping analysis show that gamma ray and neutron porosity validate the separation of the Brown Niagara formation into three statistically different zones based on log properties; the main pay zone (MPZ), the transition zone (TZ), and the water zone (WZ). The sonic and bulk density logs distinguished the WZ from the two other zones. This study is part of the Midwestern Regional Carbon Sequestration Partnership (MRCSP) Michigan Basin Large-Scale Injection Project under DOE/NETL Cooperative Agreement # DE- FC26-0NT42589 with co-funding by Core Energy, LLC, and several other partners.