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

摘要

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.