Comparison of methods for geologic storage of carbon dioxide in saline formations

• Six prospective CO2 methods were applied to 13 saline formation data sets.
• Compared CO2 resource estimates for saline formations using the same input data for open and closed boundaries.
• Methods to estimate CO2 storage include CSLF, DOE, and USGS.
• Multiple storage methods can be treated as giving statistically comparable results.
• Uncertainty in geologic parameters affects storage estimates more than method choice.

Preliminary estimates of CO2 storage potential in geologic formations provide critical information related to Carbon Capture, Utilization, and Storage (CCUS) technologies to mitigate CO2 emissions. Currently multiple methods to estimate CO2 storage and multiple storage estimates for saline formations have been published, leading to potential uncertainty when comparing estimates from different studies. In this work, carbon dioxide storage estimates are compared by applying several commonly used methods to general saline formation data sets to assess the impact that the choice of method has on the results. Specifically, six CO2 storage methods were applied to thirteen saline formation data sets which were based on formations across the United States with adaptations to provide the geologic inputs required by each method. Methods applied include those by (1) international efforts – the Carbon Sequestration Leadership Forum (Bachu et al., 2007); (2) United States government agencies – U.S. Department of Energy – National Energy Technology Laboratory (US-DOE-NETL, 2012) and United States Geological Survey (Brennan et al., 2010); and (3) the peer-reviewed scientific community – Szulczewski et al. (2012) and Zhou et al. (2008). A statistical analysis of the estimates generated by multiple methods revealed that assessments of CO2 storage potential made at the prospective level were often statistically indistinguishable from each other, implying that the differences in methodologies are small with respect to the uncertainties in the geologic properties of storage rock in the absence of detailed site-specific characterization.