TY - GEN
T1 - Monitoring tracers with time-lapse electrical methods
T2 - Society of Exploration Geophysicists International Exposition and 82nd Annual Meeting 2012, SEG 2012
AU - Singha, Kamini
AU - Li, Li
AU - Day-Lewis, Frederick D.
AU - Regberg, Aaron B.
N1 - Funding Information:
This material is based upon work supported by the National Science Foundation Grant EAR-0747629 and Department Of Energy Grants DE-FG02-08ER64520 and DE-SC0001773, and by the U.S. Geological Survey Toxic Substances Hydrology Program.
Funding Information:
This material is based upon work supported by the National Science Foundation Grant EAR-0747629 and Department Of Energy Grants DE-FG02-08ER64520 and DESC0001773, and by the U.S. Geological Survey Toxic Substances Hydrology Program.
Publisher Copyright:
© 2012 SEG.
PY - 2012
Y1 - 2012
N2 - Tracer tests are frequently used in hydrogeology to quantify subsurface processes. These tracers are frequently assumed to travel conservatively with groundwater; however, this assumption requires additional study in the context of electrical geophysical monitoring. Tracers may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system, and consequently the fluid and bulk electrical conductivity. As a result, the measured electrical conductivity may not only reflect solely solute transport but also reactive processes. Here, we evaluate the impacts of ion exchange reactions, rate-limited mass transfer, and surface conduction on quantifying tracer mass, mean arrival time, and temporal variance using electrical methods in synthetic column experiments. Numerical examples that (1) ion exchange can lead to resistivity-estimated tracer mass, velocity, and dispersivity that may be inaccurate; (2) mass transfer leads to an overestimate in the mobile tracer mass and an underestimate in velocity when using electrical methods; and (3) surface conductance does not degrade moment estimates when high-concentration tracers are used.
AB - Tracer tests are frequently used in hydrogeology to quantify subsurface processes. These tracers are frequently assumed to travel conservatively with groundwater; however, this assumption requires additional study in the context of electrical geophysical monitoring. Tracers may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system, and consequently the fluid and bulk electrical conductivity. As a result, the measured electrical conductivity may not only reflect solely solute transport but also reactive processes. Here, we evaluate the impacts of ion exchange reactions, rate-limited mass transfer, and surface conduction on quantifying tracer mass, mean arrival time, and temporal variance using electrical methods in synthetic column experiments. Numerical examples that (1) ion exchange can lead to resistivity-estimated tracer mass, velocity, and dispersivity that may be inaccurate; (2) mass transfer leads to an overestimate in the mobile tracer mass and an underestimate in velocity when using electrical methods; and (3) surface conductance does not degrade moment estimates when high-concentration tracers are used.
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U2 - 10.1190/segam2012-1345.1
DO - 10.1190/segam2012-1345.1
M3 - Conference contribution
AN - SCOPUS:85021015379
SN - 9781622769452
T3 - Society of Exploration Geophysicists International Exposition and 82nd Annual Meeting 2012, SEG 2012
SP - 4000
EP - 4005
BT - Society of Exploration Geophysicists International Exposition and 82nd Annual Meeting 2012, SEG 2012
PB - Society of Exploration Geophysicists
Y2 - 4 November 2012 through 9 November 2012
ER -