Characterization of CO2 Storage Potential in Harquahala Basin, Arizona

Project Description

The Arizona Geological Survey (AZGS) is working to characterize CO2 storage potential in Harquahala basin, western central Arizona. The basin is favorably located between population centers of southern California and south-central Arizona, and is close to large energy producers and existing infrastructure. The basin is deep and possesses a mix of saline aquifers and basalt formations, providing sufficient volume to store large volumes of CO2. Also, the basin has probable bedded salt that could provide an adequate seal for hydrogen storage, giving yet another dimension to the project.

AZGS is collaborating with several partners including NIKOLA Motor Company, Salt River Project, Arizona Public Service and Tucson Electric Power. The main objective is to compile and integrate all existing data to deliver subsurface map products that highlight important reservoir characteristics, identify data gaps, and can be used to guide a future data acquisition program.

This project will provide needed data to the CUSP, and is intended to set the stage for a Phase 2 project where data acquisition such as geophysical surveys and a characterization well will be proposed.



CUSP Team 

Project Lead: Briant Gootee (Arizona Geological Survey)

Primary Goal

Pre-feasibility evaluation for potential underground storage of CO2

Project Duration

24 months

Impact on Carbon Storage


Anticipated Volume/Year


Harquahala basin outline and depth-to-bedrock contours in meters (light gray). Power plants located in SE corner, natural gas pipelines (purple), Interstate 10 (dark gray), Colorado Arizona Project (CAP) canal (blue).
                                      Project Objectives
  • Collect data, process seismic, create basin cross-sections and construct model layers for 3-D model development in Phase II
  • Cultivate partnerships with energy companies
  • Identify data needs and recommendations for Phase 2
  • Update CUSP databases
  • Publish Open-File Report
  • Develop a Phase 2 project proposal with partners
                        Why Harquahala?
  •  Deep basin with sufficient volume
  • Three potential geologic storage types:
      • Hypersaline aquifer – liquid CO2
      • Bedded salt – potential H2 storage
      • Basalt – CO2 mineralization
  • Potential large volume of saline groundwater
  • Favorable geothermal potential
  • Proximity to large energy producers
  • Existing pipeline ROW between southern AZ and CA
  • Low seismicity risk
  • Unknown sealing potential
  • Poor subsurface well control
Statewide distribution of sedimentary basins with storage potential below 800 m depth, ranked from least to most potential