LUCI: A facility at DUSEL for large-scale experimental study of geologic carbon sequestration

LUCI, the Laboratory for Underground CO₂ Investigations, is an experimental facility being planned for the DUSEL underground laboratory in South Dakota, USA. It is designed to study vertical flow of CO₂ in porous media over length scales representative of leakage scenarios in geologic carbon sequestration. The plan for LUCI is a set of three vertical column pressure vessels, each of which is ∼500 m long and ∼1 m in diameter. The vessels will be filled with brine and sand or sedimentary rock. Each vessel will have an inner column to simulate a well for deployment of down-hole logging tools. The experiments are configured to simulate CO₂ leakage by releasing CO₂ into the bottoms of the columns. The scale of the LUCI facility will permit measurements to study CO₂ flow over pressure and temperature variations that span supercritical to subcritical gas conditions. It will enable observation or inference of a variety of relevant processes such as buoyancy-driven flow in porous media, Joule-Thomson cooling, thermal exchange, viscous fingering, residual trapping, and CO₂ dissolution. Experiments are also planned for reactive flow of CO₂ and acidified brines in caprock sediments and well cements, and for CO₂-enhanced methanogenesis in organic-rich shales. A comprehensive suite of geophysical logging instruments will be deployed to monitor experimental conditions as well as provide data to quantify vertical resolution of sensor technologies. The experimental observations from LUCI will generate fundamental new understanding of the processes governing CO₂ trapping and vertical migration, and will provide valuable data to calibrate and validate large-scale model simulations.