Estimating CO2 storage resource volumes using a Static Earth Model of the St. Peter Sandstone in the Northern Michigan Basin

Abstract

The St. Peter sandstone in the Michigan Basin has been identified through previous studies as a potential storage reservoir due to its thickness (205-1180 ft.), porosity (0-38.5 %), permeability (0-124 mD), and lateral extent. However, few wells have been drilled, limiting detailed studies of the reservoir. Three lithofacies (L1, L2, and L3) within the St. Peter sandstone were identified using core and wireline logs and further investigated using 2D maps and cross sections to characterize each lithofacies’ structure, petrophysical properties, and CO2 resource estimate. Regional 3D static earth models (SEM) allow valuable insights into the geologic heterogeneity of potential CO2 reservoirs that cannot be derived from 2D analyses in regions with sparse datasets, like the Ordovician St. Peter sandstone. Integration of wells tops, petrophysical logs, whole core, and expert knowledge of the geology went into developing the first regional 3D SEM of the St. Peter sandstone lithofacies in northern Michigan. The model has been built to facilitate current CCS project efforts and serve as a foundation for future site feasibility assessment and selection. Using Petrel™ software, a 3D structural framework of the St. Peter sandstone was created and populated with key petrophysical properties such as porosity and permeability. Pore volumes were calculated for each cell using bulk volume and porosity to determine available associated CO2 storage quantities and identify areas with high geologic storage potential in the St. Peter sandstone. Preliminary deterministic estimates for the potential mass of CO2 equivalent to the net pore volume were calculated in the regional SEM. These range from 1.5– 5.2 GT (gigatonnes) for the p10-p90 values with a p50 of about 3 GT. The p50 values for the LF1, LF2, and LF3 are 0.6, 1.4, and 0.9 GT, respectively. The highest injectivity and largest connected reservoir volumes are seen in LF3 in the northeastern and southwestern regions of the study area and are promising prospects for CO2 sequestration. This projected was supported by the Department of Energy (DOE) under Award Number DEFE0029276 with co-funding by Core Energy, LLC and other team members.

AAPG Datapages/Search and Discovery Article #90335 © 2018 AAPG 47th Annual AAPG-SPE Eastern Section Joint Meeting, Pittsburgh, Pennsylvania, October 7-11, 2018