Eruption dynamics of CO2-driven cold-water geysers: Crystal, Tenmile geysers in Utah and Chimayo geyser in New Mexico

The CO2 bubble volume fraction, eruption velocity, flash depth and mass emission of CO2 were determined from multiple wellbore CO2-driven cold-water geysers (Crystal and Tenmile geysers, in Utah and Chimayo geyser in New Mexico). At shallow depths the bubble volume fraction ranges from 0 to 0.8, eruption velocities range from 2 to 20 m/s and flash depths are predominately shallow ranging from 5 to 40 m below the surface. Annual emission of CO2 is estimated to be (4.77 +/- 1.92) x 10(3), (6.17 +/- 1.73) x 10(1), (6.54 +/- 0.57) x 10(1) t/yr for Crystal, Tenmile and Chimayo geysers, respectively. These estimates are coherent with Burnside et al. (2013) showing that the rate of CO2 leakage from wellbores is greater than fault-parallel or diffuse CO2 leakage. The geyser plumbing geometry consists of a vertical wellbore which allows for the upward migration of CO2-rich fluids due to artesian conditions. The positive feedback system of a CO2-driven eruption occurs within the well. Active inflow of CO2 into the regional aquifers through faulted bedrock allows geysering to persist for decades. Crystal geyser erupts for over 24 h at a time, highlighting the potential for a wellbore in a natural environment to reach relatively steady-state high velocity discharge. Mitigating high velocity CO2-driven discharge from wellbores will, however, be easier than mitigating diffuse leakage from faults or into groundwater systems. (C) 2014 Elsevier B.V. All rights reserved.