Regional‐scale advective, diffusive, and eruptive dynamics of CO₂ and brine leakage through faults and wellbores

Abstract

Regional-scale advective, diffusive, and eruptive transport dynamics of CO 2 and brine within a natural analogue in the northern Paradox Basin, Utah, were explored by integrating numerical simulations with soil CO 2 flux measurements. Deeply sourced CO 2 migrates through steeply dipping fault zones to the shallow aquifers predominantly as an aqueous phase. Dense CO 2 -rich brine mixes with regional groundwater, enhancing CO 2 dissolution. Linear stability analysis reveals that CO 2 could be dissolved completely within only~500 years. Assigning lower permeability to the fault zones induces fault-parallel movement, feeds up-gradient aquifers with more CO 2 , and impedes down-gradient fluid flow, developing anticlinal CO 2 traps at shallow depths (<300 m). The regional fault permeability that best reproduces field spatial CO 2 flux variation is estimated 1 × 10 À17 ≤ k h < 1 × 10 À16 m 2 and 5 × 10 À16 ≤ k v < 1 × 10 À15 m 2 . The anticlinal trap serves as an essential fluid source for eruption at Crystal Geyser. Geyser-like discharge sensitively responds to varying well permeability, radius, and CO 2 recharge rate. The cyclic behavior of wellbore CO 2 leakage decreases with time.

Differential depth distribution of microbial function and putative symbionts through sediment-hosted aquifers in the deep terrestrial subsurface

“…The CO 2 was probably generated from thermal decomposition of Pennsylvanian-aged carbonate rocks 26, 51,52 . CO 2 gas and brine formed by groundwater dissolution of Paradox evaporites migrate via faults and fractures 53,54 . b , The community profile of 505 organisms strongly followed the succession of the geyser eruptions (blue lines, NMDS).…”

Modelling of Long-term Along-fault Flow of CO2 From a Natural Reservoir

“…For an accumulation of 100 MT, this corresponds to 0.003% -0.2 % leakage per year, which is a factor 3 -200 above the often quoted 1% in 1000 years as (from a climate change perspective) acceptable surface leak rate for CO2 storage sites (see Roberts et al [9] for a recent overview of considerations and values). This excludes the contribution from Crystal Geyser, a poorly abandoned (uncapped) exploration well dating back to 1936, for which Gouveia and Friedman [10] estimate leaked an average rate of about Electronic copy available at: https://ssrn.com/abstract=3816437 11 kT/yr in 2005, although likely declining with time [11,12]. In our modelling we also excluded Crystal Geyser (although it could be included as part of future work), thus ignoring feedback loops with nearby soil fluxes [4,12].…”

Measurements in degassing processes of CO 2 solution with particular reference to CO 2 -driven limnic eruptions

“…Once CO 2 leakage happens in these reservoirs, there are possibilities of the CO 2 -brine leakage via faults. The brine can migrate and eventually reach near-surface water leading to the potential of eruption [Jung et al, 2015, Lewicki et al, 2007, Shipton et al, 2005. Limnic eruption related studies have also been carried out recently.…”