Characterize subsurface 3-D geological heterogeneity in targeted CO2 storage reservoirs in the Rock Springs Uplift: Wyoming’s highest-priority saline aquifer for CO2 storage

Abstract

The several CCS projects conducted by researchers from the UW and partners conducted have documented that the Rock Springs Uplift (RSU) is a promise CO2 storage location characterized by its favorable geologic conditions and structure. The RSU is a 35 mile × 50 mile anticline with 4-way closure, 10,000 feet of structural relief, multiple outstanding confining layers above the favorable storage reservoir intervals, and 8,000 feet of vertical separation from fresh water aquifers (USDW). However, the greatest uncertainty in CO2 injection or CO2 storage processes is characterizing geological heterogeneity in three dimensions and operatively managing the reservoir pressure. In Southwest Wyoming, the reservoir intervals with the greatest potential for CO2 storage are the Mississippian Madison Limestone, Pennsylvanian Tensleep/Weber Sandstone, and Jurassic Nugget Sandstone. To substantially reduce risk in modeling CO2 storage in these reservoirs, researchers in Center for Economic Geology Research have integrated 3-D seismic data with results from well log analysis and core observations to construct detailed porosity, permeability, lithofacies, and fracture distribution volumes. A 5 mile × 5 mile 3-D seismic survey and a 12,810-foot-deep stratigraphic test well (more than 910 feet of core and complete log suite retrieved) are the basis of this construction. The three-dimensional distribution of heterogeneity in petrophysical properties of the reservoir intervals results from the seismic/log/core/geology integration. Within the volumes, we can now isolate individual reservoir horizons and construct maps of the distribution of petrophysical properties. Dynamic models were constructed based on detailed reservoir characterization, and run for various injection and storage scenarios. The extensive CO2 injection and storage perform assessment has done for the priority RSU commercial scale CO2 geological storage site. The results from this project have significant utility in reducing risk for diverse commercial scale CO2 storage projects in the Rocky Mountain region. This work establishes a strategy for dealing with projects relating to deep (>10,000 feet) injection/storage and production brine in deep saline aquifers – reservoirs generally considered too deep and/or too tight.

AAPG Datapages/Search and Discovery Article #90357 ©2019 AAPG Rocky Mountain Section Meeting, Cheyenne, Wyoming, September 15-18, 2019