Spatiotemporal changes in CO2 emissions during the second ZERT injection, August–September 2008

Abstract

This study reports the first field test of a multichannel, auto-dilution, steady-state, soil-CO 2 flux monitoring system being developed to help understand the pathways by which fugitive CO 2 from a geologic sequestration site migrates to the surface. The test was conducted from late August through mid-October 2008 at the Zero Emissions Research and Technology project site located in Bozeman, MT. Twenty steady-state and five non-steadystate flux chambers were installed in a 10 9 15 m area, one boundary of which was directly above a shallow (2-m depth) horizontal injection well located 0.5 m below the water table. A total flux of 52 kg CO 2 day -1 was injected into the well for 13 days and the efflux from the soil was monitored by the chambers before, during, and for 33 days after the injection. The results showed a rapid increase in soil efflux once injection started, with maximal values reached within 3-7 days in most chambers. Efflux returned to background levels within a similar time period after injection ceased. A radial efflux pattern was observed to at least 2 m from the injection well, and evidence for movement of the CO 2 plume during the injection, presumably due to groundwater flow, was seen. The steadystate chambers yielded very stable data, but threefold to fivefold higher fluxes than the non-steady-state chambers. The higher fluxes were attributed to vacuum induced in the steady-state chambers by narrow vent tubes. High winds resulted in significant decreases in measured soil CO 2 efflux, presumably by enhancing efflux from soil outside the chambers.

Persistent wind-induced enhancement of diffusive CO2transport in a mountain forest snowpack

“…Wind effects on soil gases, some penetrating to many decimeters, have been reported in moss organic horizons of boreal forests [ Hirsch et al , 2004], in crop soils [ Reicosky et al , 2008], those of a temperate grassland [ Flechard et al , 2007], a Scots pine forest [ Maier et al , 2010], an urban temperate deciduous stand [ Fujiyoshi et al , 2010], and soils subjected to volcanic outgassing [ Viveiros et al , 2009]. Experimental studies with CO 2 leakage from geologic storage sites have identified the importance of nondiffusive transport [ Amonette et al , 2010; Lewicki et al , 2010], and it can be a factor influencing radon emission [ Fujiyoshi et al , 2010], contaminant transport [ Auer et al , 1996], and geochemical redox processes [ Elberling et al , 1998].…”

Characteristics of soil CO2 under different conditions and its influence on water chemical composition: an experimental and modeling study in the laboratory

“…With the development of CO 2 geological storage technology (Eiken et al 2011), the problem of CO 2 leakage in ecosystems is becoming increasingly serious (Oldenburg et al 2010;Patil et al 2010). CO 2 leakage can change soil physical and chemical properties and the soil environment by changing soil gas (Amonette et al 2010), water (Nicot, 2009), pH (Patil et al 2010), and composition and the activity of the soil microbial community (Morozova et al 2011), and it will affect soil carbon sequestration capacity (West et al 2009).…”

Quantitative assessment of soil CO2 concentration and stable carbon isotope for leakage detection at geological carbon sequestration sites

“…[16][17][18][19][20] Field demonstration by releasing CO 2 into near-surface environments to simulate leakage from a CO 2 storage formation is one of most effective ways of testing and validating near-surface monitoring technologies, although to date few field experiments of controlled CO 2 injection into the vadose zone have been reported in the literature for purposes of either testing the sensitivity of soil CO 2 measurements so as to detect CO 2 leakage signals or studying the impacts of CO 2 leakage on soil ecosystems. Various achievements have been reported, such as CO 2 concentration and flux measurements, [23][24][25][26] carbon isotopes of CO 2 monitoring, 20,[27][28][29] tracers (Rn 222 and perfluorocarbon) detection, 20,30 net flux of CO 2 in the atmosphere with eddy covariance monitoring, 31 and soil gas composition measurements. Various achievements have been reported, such as CO 2 concentration and flux measurements, [23][24][25][26] carbon isotopes of CO 2 monitoring, 20,[27][28][29] tracers (Rn 222 and perfluorocarbon) detection, 20,30 net flux of CO 2 in the atmosphere with eddy covariance monitoring, 31 and soil gas composition measurements.…”

“…19,21,22 The field site of Zero Emission Research and Technology Center (ZERT) in Bozeman, MT, USA, has served as an ideal test bed for developing new MVA technologies and numerical models for leakage detection. Various achievements have been reported, such as CO 2 concentration and flux measurements, [23][24][25][26] carbon isotopes of CO 2 monitoring, 20,[27][28][29] tracers (Rn 222 and perfluorocarbon) detection, 20,30 net flux of CO 2 in the atmosphere with eddy covariance monitoring, 31 and soil gas composition measurements. 32 Several numerical models have been developed and validated with the field data obtained at this site, mainly for assessing CO 2 flux and/or CO 2 concentration for leakage detection.…”