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| Titel |
Single-well and inter-well dual-tracer tests for CCS pilot site characterization at Heletz (Israel): scope and limitations |
| VerfasserIn |
Julia Ghergut, Jac Bensabat, Auli Niemi, Tobias Licha, Torsten Lange, Alexandru Tatomir, Martin Sauter |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075012
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| Zusammenfassung |
| A semi-analytical approximation to tracer signals is proposed for evaluating the
chances of unambiguous tracer test interpretation for the CCS pilot site at Heletz
(www.co2mustang.eu/Heletz.aspx), given the multiple constraints imposed upon tracer test
execution at any deep geological formation regarding maximum pressure buildup admissible,
fluid turnover rates, injection-fluid availability and conditioning capabilities, fluid disposal
capacity, maximum test duration, tracer quantities/species available, tracer metering costs,
etc. At the Ketzin site in Germany (www.co2sink.org), such constraints acted prohibitively
towards conducting any tracer tests prior to CO2 injection (cf. EGU2009-11625,
EGU2011-2823-1). In contrast, at the Heletz site within the MUSTANG project,
a particular sequence of single-well (SW) and inter-well (IW) tracer tests to be
conducted prior to CO2 injection (Bensabat et al. 2011, Niemi et al. 2011) is being
regarded as a critical, indispensable contribution towards the goal of georeservoir
characterization.
An advantage of the proposed approach, expressing tracer signals U in terms of fluid
volume recovery fraction f (rather than time), is its independence upon IW distance
and upon fluid injection/production rates (which may be difficult to prescribe in
advance). It roughly predicts conservative- and sorptive-tracer signals, fluid mixing and
temperature evolution in SW and IW tests, for stratified georeservoirs whose high- and
low-permeability layers have thicknesses of same magnitude order. Thus, besides the CCS
context, it can be extended to a range of geothermal applications, including some
aquifer-dominated systems in the Upper Rhine Rift Valley, S-German Malm/Molasse Basin,
N-German Sedimentary Basin, but excluding fracture-dominated (petrothermal)
systems.
IW tracer signals are sensitive to storage capacity (measured by transport-effective
porosities n), but suffer from ambiguity between longitudinal heterogeneity (Peclet number
Pe) and vertical heterogeneity (hydrostratigraphy Prf(z)), and from all-parameter ambiguity at
early times (f |
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