WIRELINE SIGNATURES OF CONTINENTAL FLOOD BASALT LITHOFACIES IN A CARBON SEQUESTRATION PILOT WELL

Chemically reactive continental flood basalts form an important sequestration target for anthropogenic carbon dioxide, especially in areas that lack conventional sedimentary targets. The Miocene Columbia River Basalt Group of the northwest United States forms regional aquifers and has the potential to sequester gigatons of supercritical CO₂ in stacks of porous and permeable flow tops separated by massive basalt flow interiors. Only a handful of studies exist which examine techniques to exploit conventional wire-line log data to identify basalt textures and lithofacies relevant to CO₂ sequestration. In this study, we continue to address that knowledge gap. We integrate wire-line log and rock data from the 2009 Big Sky Carbon Sequestration Partnership basalt pilot well near Wallula, Washington U.S.A. with outcrop observations and regional data to identify patterns for recognition of basalt lithofacies. We incorporate techniques used in hydrocarbon exploration of basalt terrains and expand on the work of Nelson et al. to include new possible flow signatures which have stratigraphic, storage, and geomechanical implications for the evaluation of reservoirs and seals for long-term carbon dioxide sequestration in basalts of the northwestern U.S. and elsewhere.