Sinking CO2 in Supercritical Reservoirs

ABSTRACT: Abstract Geologic carbon storage is required for achieving negative CO2 emissions to deal with the climate crisis. The classical concept of CO2 storage consists in injecting CO2 in geological formations at depths greater than 800 m, where CO2 becomes a dense fluid, minimizing storage volume. Yet CO2 has a density lower than the resident brine and tends to float, challenging the widespread deployment of geologic carbon storage. Here, we propose for the first time to store CO2 in supercritical reservoirs to reduce the buoyancy?driven leakage risk. Supercritical reservoirs are found at drilling?reachable depth in volcanic areas, where high pressure (p > 21.8 MPa) and temperature (T > 374°C) imply CO2 is denser than water. We estimate that a CO2 storage capacity in the range of 50–500 Mt yr?1 could be achieved for every 100 injection wells. Carbon storage in supercritical reservoirs is an appealing alternative to the traditional approach. Key Points We propose a novel geologic carbon storage concept that reduces the buoyancy?driven CO2 leakage risk By injecting CO2 in reservoirs where the resident water stays in supercritical conditions, CO2 sinks because it is denser than pore water Supercritical reservoirs are found at relatively shallow depths between 3 and 5 km in deep volcanic areas

SUBMITTER: Parisio F 

PROVIDER: S-EPMC7780548 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature