The project team—led by the University of Wyoming’s Carbon Management Institute and sponsored by the Office of Fossil Energy’s National Energy Technology Laboratory—gathered geologic, hydrologic and geochemical data from a 12,810-foot-deep stratigraphic test well drilled to evaluate the area’s potential as a long-term, high-volume storage site for CO₂.

The Rock Springs Uplift, a geologic feature in southwestern Wyoming, was found to have the sought-after combination of (1) ideal geological characteristics for carbon storage, and (2) proximity to some of Wyoming’s largest sources of anthropogenic CO₂ emissions.

To evaluate the site’s potential for CO₂ storage, the project team performed digital imaging of a core sample to learn about the formation’s grain size, mineralogy, facies distribution, and porosity. In addition, the team studied a comprehensive set of geophysical data from the test well, focusing on two potential CO₂ storage reservoirs—the Madison Limestone and the Weber/Tensleep Sandstone—and the overlying formations that would trap the CO₂ at depth.

The researchers discovered that, along with the promise of a prime CO₂ storage space, the deep saline waters of the Rock Springs Uplift contain high, commercially viable concentrations of lithium: ~190 parts per million for the Weber/Tensleep Sandstone, and ~130 parts per million for the Madison Limestone.

For every 1 million metric tons of CO₂ stored, approximately 250 metric tons of lithium carbonate, with an approximate market value of $1.6 million, could be recovered from processed brine. Lithium, which is used in batteries and other electronics applications, has become vital as many nations transition to greener technologies. The recovered lithium could generate revenue to offset the cost of CO₂ storage and help reduce the need for lithium import.

In addition to the testing completed within the characterization well, and on samples removed from it, the project team performed a three-dimensional seismic survey of a 25-square-mile area around the test site. The seismic data allowed the researchers to extrapolate the geologic properties measured in the well—such as porosity, permeability, and fluid saturation—to the rocks throughout the two storage reservoirs and confining formations. This made it possible to build realistic three-dimensional geologic models of these formations. Combining this with information gathered in the lab from the core samples, the researchers developed realistic assessments of how injected CO₂ would behave in the storage reservoirs, which in turn yielded greatly improved CO₂ storage capacity estimates.

This research effort, funded by the American Recovery and Reinvestment Act of 2009, will provide significant information to the National Carbon Sequestration Database and Geographic Information System (NATCARB), a geographic information system–based tool developed by the National Energy Technology Laboratory to provide a view of carbon capture and storage potential nationwide. The results could also lay the groundwork for a future large-scale carbon capture and storage project in Wyoming.

Resources

• Site Characterization of the Highest-Priority Geologic Formations for CO₂ Storage in Wyoming - University Of Wyoming