Characteristics of <scp>CO</scp>₂‐driven cold‐water geyser, <scp>C</scp>rystal <scp>G</scp>eyser in <scp>U</scp>tah: experimental observation and mechanism analyses

Abstract

Abstract Geologic carbon capture and storage ( CCS ) is an option for reducing CO 2 emissions, but leakage to the surface is a risk factor. Natural CO 2 reservoirs that erupt from abandoned oil and gas holes leak to the surface as spectacular cold geysers in the C olorado P lateau, U nited S tates. A better understanding of the mechanisms of CO 2 ‐driven cold‐water geysers will provide valuable insight about the potential modes of leakage from engineered CCS sites. A notable example of a CO 2 ‐driven cold‐water geyser is C rystal G eyser in central U tah. We investigated the fluid mechanics of this regularly erupting geyser by instrumenting its conduit with sensors and measuring pressure and temperature every 20 sec over a period of 17 days. Analyses of these measurements suggest that the timescale of a single‐eruption cycle is composed of four successive eruption types with two recharge periods ranging from 30 to 40 h. Current eruption patterns exhibit a bimodal distribution, but these patterns evolved during past 80 years. The field observation suggests that the geyser's eruptions are regular and predictable and reflect pressure and temperature changes resulting from J oule– T homson cooling and endothermic CO 2 exsolution. The eruption interval between multiple small‐scale eruptions is a direct indicator of the subsequent large‐scale eruption.