Scott Quillinan

Regional Geologic History, CO2 Source Inventory, and Groundwater Risk Assessment of a Potential CO2 Sequestration Site on the Rock Springs Uplift in Southwest Wyoming

The location of a potential carbon capture and sequestration (CCS) project in southwest Wyoming is evaluated with emphasis on the site location, geologic history, location of potential drinking-water aquifers, and proximity to sources of both anthropogenic and natural CO2. Natural and anthropogenic CO2 sources were mapped in Wyoming to define their relation to enhanced oil recovery opportunities and prospective storage sites. Of the nearly 60 Mt of anthropogenic CO2 emissions reported in Wyoming, half were located in the Greater Green River Basin (GGRB) in southwest Wyoming. The Rock Springs Uplift (RSU) CO2 storage site is located in the GGRB, and is a promising structure for commercial CO2 storage/surge tank development. Successful economic utilization of natural and anthropogenic CO2 depends on near-by sources, infrastructure, areas of resource depletion suitable for enhanced recovery, and areas of potential storage.

Reservoir Fluid Characterization of the Weber Sandstone and Madison Limestone on the Rock Springs Uplift in Southwest Wyoming

Formation brine characterization provided the data for analytical permitting requirements, evaluating reservoir confinement, and reaction path modeling. The brines of the Weber Sandstone and Madison Limestone of the Rock Springs Uplift are sodium-chloride type with total dissolved solid concentrations in excess of 75,000 mg/L. Due to the high TDS the Wyoming Department of Environmental Quality has classified these as Class VI groundwater.

Displaced Fluid Management—the Key to Commercial-Scale Geologic CO2 Storage

The most critical problem with commercial scale geological CO2 sequestration is management of displaced fluids. All of the high quality numerical simulations of carbon capture, utilization, and storage (CCUS) on the Rock Springs Uplift (RSU), utilizing realistic 3-D reservoir models, demonstrate that commercial-scale geological CO2 storage will require the removal of formation brines in approximately 1:1 ratio of injected CO2 to displaced fluid. Without the production of formation brines the simulations suggest that very quickly injected CO2 will cause pressures in the storage domain to exceed fracture pressures. To solve this problem, Carbon Management Institute (CMI) proposed a strategy that includes integration of fluid production/treatment with injection of CO2. The treatment of the brines involved three important steps: (1) use of the temperature of the produced brines (~100 °C) to produce electricity via a heat exchanger to power the treatment facility, (2) to separate fresh water from the brines via nanofiltration and reverse osmosis, and (3) to recover metals, notably lithium, from the residual brines after partial evaporation. The impact of this approach; production of electricity, fresh water, and metals such as lithium from produced brines transform an anticipated carbon storage penalty into a revenue center.