Probabilistic Aggregation of Individual Assessment Units in the U.S. Geological Survey National CO2 Sequestration Assessment.

Abstract: The U.S. Geological Survey is conducting a probabilistic national assessment of CO₂ storage resources in ∼200 storage assessment units (SAUs), and must present results at basin, regional, and national scales. To calculate combined resources with correctly propagated uncertainty requires a probabilistic aggregation procedure in which correlations between SAUs are estimated. A comparison of single- and multiple-stage aggregation methods shows that the former better represents the varied geology within and between basins. Pairwise SAU correlation coefficients are estimated by geologists. If the matrix is not positive semi-definite, it is adjusted. Subsets of the matrix are extracted for basin or regional calculations. [Copyright &y& Elsevier]