Estimating Carbon Dioxide Storage in Geologic Formations
This map highlights potential regions of carbon dioxide storage for coal beds, oil and gas reservoirs, and saline formations that were assessed by the Regional Carbon Sequestration Partnerships and other sources and compiled by NATCARB.
Carbon, Capture, and Storage (CCS) is an option to reduce carbon dioxide (CO2) emissions. Carbon emissions are captured from stationary sources such as power plants and then injected in the form of supercritical CO2 into select deep geologic formations. Formations such as depleted oil and gas fields, deep saline formations, and unmineable coal seams have a competent seal and geologic trapping capability that will prevent CO2 from escaping back into the atmosphere. Estimates of CO2 storage capacity in geologic formations are required to assess the potential for CCS technologies to contribute towards reducing CO2 emissions globally. Governments and industries worldwide rely on these estimates for broad energy-related government policy and business decisions. Dependable CO2 storage estimates are necessary to ensure successful deployment of CCS technologies
Current estimates of CO2 storage in saline formations are subject to relatively large uncertainties. These assessments rely on simplifying assumptions due to lack of data from the subsurface associated with areas of potential storage in saline formations and the natural heterogeneity of geologic formations in general, resulting in undefined rock properties.
Initiatives for assessing CO2 geologic storage potential have been conducted since 1993. These initiatives vary from an overview description of assessment tools to a detailed, comprehensive method. While dependable prospective CO2 storage estimates provide essential information for policy and business decisions for CCS technologies, it is difficult to assess the uncertainty of these estimates without knowing how the methods targeted at CO2 storage estimates compare with one another.
Researchers at NETL compared a variety of CO2 storage methods for geologic storage in saline formations to determine if the method used for estimation of storage resource significantly impacts the results. Specifically, six prospective CO2 methods were applied to 13 saline formation data sets. Methods applied include those normally utilized by 1) international organizations; 2) U.S. Department of Energy and United States Geological Survey ); and 3) the peer-reviewed scientific community.
Despite the uncertainties arising from the simplifying assumptions inherent to each method, the assessments of CO2 storage potential were comparable. A statistical analysis revealed that the uncertainty in the underlying parameters of the general saline formation data sets has a much greater impact on overall prospective estimates of CO2 storage than the choice of method does, especially within subsets of methods defined by similar assumptions.
These results were recently published as a NETL Technical Report Series as NETL-TRS-1-2013, Comparison of Publicly Available Methods for Development of Geologic Storage Estimates for Carbon Dioxide in Saline Formations.
Contact: Angela Goodman