25. Geologic storage of CO₂: Potential environmental and human health effects

Anthropogenic activity and the burning of fossil fuel have caused a continuous and dramatic increase of atmospheric CO₂ over the past 120 years and its role as a greenhouse gas and its potential effect on global climate have been well documented. Power plants are a major source of anthropogenic CO₂ and although the capture, or scrubbing of CO₂ is a proven technology, its disposal and storage remain problematic. CO₂ sequestration in geologic formations is increasingly being studied as a strategy for limiting CO₂ emissions to the atmosphere. But, there are major uncertainties involving the environmental impact and long-term stability of CO₂ disposed in deep aquifers, in the oceans, in depleted oil and gas reservoirs, salt domes, and in deep coal seams. To date, research on the geologic storage of CO₂ has focused primarily on storage feasibility and reservoir capacity. But, there is growing concern about the integrity of reservoir seals to contain CO₂ and potential contamination of groundwater resources with heavy metals and toxic organic compounds released by the interaction of CO₂ with formation rocks. Both liquid and aqueous CO₂ are reactive in the sub-surface. Liquid CO₂ is a very effective organic solvent for polycyclic aromatic and other hydrocarbons; many are known carcinogens. Aqueous CO₂ reacts with water to produce an extremely acidic solution, capable of dissolving minerals and releasing metals to solution. Carbonate minerals are integral to the integrity of the reservoirs helping seal pores and fractures in the cap rock, that if opened could release CO₂ and contaminated brine into overlying aquifers that supply drinking and irrigation water. Moreover, the acid solution could corrode the cement seals plugging abandoned oil or gas wells, 2.5 million of which exist in the United States.

Environmental geochemistry research conducted under this opportunity will explore the fundamental chemical reactions between liquid CO₂ and potential reservoir fluids and rocks. The potential exists to better understand the risks and hazards associated with geologic storage and to identify both favorable and unfavorable disposal and storage options. To that end, we seek a research geochemist to carry out a combination of modeling and experimental studies to provide some understanding of the reactivity of potential reservoir cap rocks in the presence of molecular and dissolved CO₂, specifically to 1) identify the type and extent of chemical reactions that occur to resolve some of the uncertainty involving the disposal of CO₂, 2) to identify and quantify hazardous chemicals dissolved in solution by the interaction of CO₂ charged fluids with formation rocks, 3) to identify rock and reservoir types and environmental conditions likely to retain CO₂ and environmental contaminants, and 4) to model the thermodynamic stability of the system. This is an opportunity for scientific leadership in providing essential data and guidance for pilot site characterization and monitoring.

Applicants for this Research Opportunity are encouraged to submit proposals that rely on a combination of theory and experimentation. Extensive laboratory facilities are located at the USGS Menlo Park Science Center, including a water/rock experimental laboratory utilizing flexible gold reaction-cell technology to study liquid-vapor-solid systems over a wide range of temperature and pressure conditions, with a unique capability for serial on-line sampling of the liquid/vapor phases. Expected outcome of this Opportunity will benefit researchers in government, industry, and academia who are involved in sequestration technologies and in developing and implementing a sequestration strategy.

Proposed Duty Station: Menlo Park, CA

Areas of Ph.D.: Geochemistry, geology, environmental science

Qualifications: Applicants must meet one of the following qualifications: Research Chemist, Research Geologist

(This type of research is performed by those who have backgrounds for the occupations stated above. However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Research Advisor(s): Robert Rosenbauer, (650) 329-4198, brosenbauer@usgs.gov; Yousif Kharaka, (650) 329-4535, ykharaka@usgs.gov; Robert Burrus, (703) 648-6144, burruss@usgs.gov

Human Resources Office contact: Erica Settlemyer, (916) 278-9383, esettlemyer@usgs.gov

Summary of Opportunities