The University of Texas at Austin and their partners at Los Alamos National Laboratory (LANL), Environmental Defense Fund, and Sandia Technologies, LLC are investigating Texas offshore subsurface storage resources in the Gulf of Mexico as candidate geologic storage formations (Figure 1). This project will identify one or more CO2 injection site(s) within an area of Texas offshore state lands (extending approximately 10 miles from the shoreline) that are suitable for the safe and permanent storage of CO2 from future large-scale commercial CCS operations (Figure 2). The approach for identifying these injection sites is to use both historic and new data to evaluate the candidate geologic formations. Additional work will be conducted to evaluate the effects of chemical reactions resulting from injection of CO2 into the identified formations and their effects on potential commercial-level injection. A risk analysis and mitigation plan will also be generated in support of near-term commercial development efforts.
The project team will refine CO2 storage resource estimates for Miocene-age geologic storage formations and specific candidate reservoirs, and coordinate data sharing with the National Carbon Sequestration Database and Geographical Information System (NATCARB). In addition, the team will assess the effectiveness of confining zone(s) for retaining CO2 over a period of centuries, by evaluating brine chemical reactions and conducting reservoir simulations, and plume modeling.
Carbon capture and storage (CCS) technologies offer the potential for reducing CO2 emissions without adversely influencing energy use or hindering economic growth. Deploying these technologies in commercial-scale applications requires adequate geologic formations capable of (1) storing large volumes of CO2, (2) receiving injected CO2 at efficient and economic rates, and (3) retaining CO2 safely over extended periods. Research efforts are currently focused on conventional and unconventional storage formations within depositional environments such as: deltaic, fluvial, alluvial, strandplain, turbidite, eolian, lacustrine, clastic shelf, carbonate shallow shelf, and reef. Conventional storage types are porous permeable clastic or carbonate rocks that have fluids such as brine, oil, or gas in the natural void spaces of the rocks. Unconventional storage types include unmineable coal, organic shale, and basalt interflow zones1.
The Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) selected 10 projects that received $49 million of DOE funding to characterize promising geologic formations for CO2 storage. The funding was provided by the American Recovery and Reinvestment Act of 2009 (ARRA), which was enacted to create new jobs, spur economic activity, and promote long-term economic growth. This research further advances DOE’s efforts to develop a national assessment of CO2 storage resources in deep geologic formations. These 10 projects are focusing on the regional site characterization of high-potential geologic storage formations. They will assess and develop comprehensive data sets of storage formation characteristics (porosity, permeability, reservoir architecture, cap rock integrity, etc.) to provide insight into the potential for selected geologic reservoirs across the United States to safely and permanently store CO2. An additional $50 million of ARRA funding was provided to augment the work that the existing projects are conducting. This additional funding is allowing these projects to further characterize reservoir geology, identifying additional storage opportunities for industrial CO2 sources. This additional funding is allowing these projects to drill additional and/or deeper wells, collect significantly better log and core data to populate models, collect additional geophysical data, and integrate additional data and conduct more extensive reservoir models.
The overall effort will provide greater insight into the potential for geologic formations across the United States to safely and permanently store CO2. The information gained from this endeavor will further DOE efforts to refine a national assessment of CO2 storage capacity in deep geologic formations. Specifically, the project’s ability to develop and utilize offshore geologic storage resources could contribute significantly to the management of CO2 emissions from various emission sources located in southeastern Texas. The University of Texas at Austin has partnered with the General Land Office of Texas, the owner of these offshore lands. This single-owner situation avoids typically troublesome issues for onshore geologic storage projects, such as liability, pore space ownership, and risk to underground sources of drinking water (protected groundwater). The results from this study are expected to provide a summary of basin-scale suitability and will identify and prioritize potential offshore CO2 geological storage opportunities. Initial estimates indicate a storage resource potential of 86 million metric tons of CO2 within the study area, and the project team is working to refine this estimate. Offshore geologic sequestration offers additional CO2 storage opportunities and may prove to be easier, safer, and less expensive than storing CO2 in geologic formations on land, particularly during the early days of commercialization. Offshore storage provides several advantages that include: (1) additional CO2 storage potential in the United States to supplement existing onshore capacity estimates; (2) locating sequestration sites away from heavily populated; and (3) reduces the risk to underground sources of drinking water.
The data gathered as part of this research effort will be shared with the Regional Carbon Sequestration Partnership’s (RCSP) Southeast Regional Carbon Sequestration Partnership (SECARB), integrated into the National Carbon Sequestration Database and Geographic Information System, and utilized for the 4th Edition of the Carbon Sequestration Atlas of the United States and Canada.
The primary objective of the DOE’s Carbon Storage Program is to develop technologies to safely and permanently store CO2 and reduce Greenhouse Gas (GHG) emissions without adversely affecting energy use or hindering economic growth. The Programmatic goals of Carbon Storage research are: (1) estimating CO2 storage capacity in geologic formations; (2) demonstrating that 99 percent of injected CO2 remains in the injection zone(s); (3) improving efficiency of storage operations; and (4) developing Best Practices Manuals (BPMs).
The primary objective of the project is to identify at least one specific site within Texas offshore state lands capable of safely and permanently storing at least 30 million metric tons of CO2 from future commercial CCS operations. To meet this objective, the project plans to use existing data from hydrocarbon exploration activity to identify candidate CO2 storage opportunities and refine storage resource calculations for optimal Miocene age rock formations within a regional area of Texas and offshore state lands. In addition to evaluating geologic storage potential of saline aquifers in Miocene formations, the project team will also develop a detailed geologic storage resource estimate for CO2. Initial estimates indicate a storage resource potential of 86 million metric tons of CO2 within the study area, though this estimate is currently being refined.
1DOE NETL 2010 - Geologic Storage Formation Classification: Understanding Its Importance and Impacts on CCS Opportunities in the United States, /technologies/carbon_seq/refshelf/BPM_GeologicStorageClassification.pdf.
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