Analysis of three sets of SWIW tracer-test data using a two-population complex fracture model for matrix diffusion and sorption

Doughty, C; Tsang, C F

doi:10.2172/981521

Title: Analysis of three sets of SWIW tracer-test data using a two-population complex fracture model for matrix diffusion and sorption

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Abstract

A complex fracture model employing two populations for diffusion and sorption is proposed to analyze three representative single-well injection-withdrawal (SWIW) tracer tests from Forsmark and Laxemar, the two sites under investigation by the Swedish Nuclear Fuel and Waste Management Company (SKB). One population represents the semi-infinite rock matrix and the other represents finite blocks that can become saturated, thereafter accepting no further diffusion or sorption. The diffusion and sorption parameters of the models are inferred by matching tracer breakthrough curves (BTCs). Three tracers are simultaneously injected, uranine (Ur), which is conservative, and rubidium (Rb) and cesium (Cs), which are non-conservative. For non-sorbing tracer uranine, the finite blocks become saturated with test duration of the order of 10 hours, and both the finite and the semi-infinite populations play a distinct role in controlling BTCs. For sorbing tracers Rb and Cs, finite blocks do not saturate, but act essentially as semi-infinite, and thus BTC behavior is comparable to that obtained for a model containing only a semi-infinite rock matrix. The ability to obtain good matches to BTCs for both sorbing and non-sorbing tracers for these three different SWIW data sets demonstrates that the two-population complex fracture model may be a useful conceptualmore »« less

Authors:: Doughty, C; Tsang, C F

Publication Date:: Sat Aug 01 00:00:00 EDT 2009

Research Org.:: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:: Earth Sciences Division

OSTI Identifier:: 981521

Report Number(s):: LBNL-3006E
TRN: US1003874

DOE Contract Number:: DE-AC02-05CH11231

Resource Type:: Technical Report

Country of Publication:: United States

Language:: English

Subject:: 54; 58; CESIUM; DIFFUSION; FRACTURES; NUCLEAR FUELS; RUBIDIUM; RUTHERFORD BACKSCATTERING SPECTROSCOPY; SORPTION; STAGNATION; WASTE MANAGEMENT

Citation Formats


                    Doughty, C, and Tsang, C F. Analysis of three sets of SWIW tracer-test data using a two-population complex fracture model for matrix diffusion and sorption.  United States: N. p., 2009. 
        Web.  doi:10.2172/981521.

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                    Doughty, C, & Tsang, C F. Analysis of three sets of SWIW tracer-test data using a two-population complex fracture model for matrix diffusion and sorption.  United States.  https://doi.org/10.2172/981521

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                    Doughty, C, and Tsang, C F. 2009.  
        "Analysis of three sets of SWIW tracer-test data using a two-population complex fracture model for matrix diffusion and sorption".  United States.  https://doi.org/10.2172/981521.  https://www.osti.gov/servlets/purl/981521.

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@article{osti_981521,

  title        = {Analysis of three sets of SWIW tracer-test data using a two-population complex fracture model for matrix diffusion and sorption},

  author       = {Doughty, C and Tsang, C F},

  abstractNote = {A complex fracture model employing two populations for diffusion and sorption is proposed to analyze three representative single-well injection-withdrawal (SWIW) tracer tests from Forsmark and Laxemar, the two sites under investigation by the Swedish Nuclear Fuel and Waste Management Company (SKB). One population represents the semi-infinite rock matrix and the other represents finite blocks that can become saturated, thereafter accepting no further diffusion or sorption. The diffusion and sorption parameters of the models are inferred by matching tracer breakthrough curves (BTCs). Three tracers are simultaneously injected, uranine (Ur), which is conservative, and rubidium (Rb) and cesium (Cs), which are non-conservative. For non-sorbing tracer uranine, the finite blocks become saturated with test duration of the order of 10 hours, and both the finite and the semi-infinite populations play a distinct role in controlling BTCs. For sorbing tracers Rb and Cs, finite blocks do not saturate, but act essentially as semi-infinite, and thus BTC behavior is comparable to that obtained for a model containing only a semi-infinite rock matrix. The ability to obtain good matches to BTCs for both sorbing and non-sorbing tracers for these three different SWIW data sets demonstrates that the two-population complex fracture model may be a useful conceptual model to analyze all SWIW tracer tests in fractured rock, and perhaps also usual multiwell tracer tests. One of the two populations should be semi-infinite rock matrix and the other finite blocks that can saturate. The latter can represent either rock blocks or gouge within the fracture, a fracture skin zone, or stagnation zones.},

  doi          = {10.2172/981521},

  url          = {https://www.osti.gov/biblio/981521},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Sat Aug 01 00:00:00 EDT 2009},

  month        = {Sat Aug 01 00:00:00 EDT 2009}

}

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