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Study of alternative tracer tests in characterizing transport in fractured rocks
Author(s) -
Tsang Y. W.
Publication year - 1995
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/95gl01093
Subject(s) - tracer , advection , matrix (chemical analysis) , diffusion , fracture (geology) , geology , inverse , flow (mathematics) , mechanics , geotechnical engineering , materials science , physics , mathematics , geometry , thermodynamics , nuclear physics , composite material
Flow and transport calculations are carried out by numerical simulation for different tracer designs: single‐well radially diverging /converging (huff‐puff), single well radially converging, and two‐well injection‐withdrawal (doublet) in a 2D fracture zone. The fractured rocks are conceptualized as a dual‐continuum: the well‐connected fractures forming a heterogeneous continuum for advective transport, and the less permeable matrix forming a second continuum for tracer diffusion. Results show that the huff‐puff design is a good diagnostic test for matrix diffusion. The two‐well doublet design averages over a large volume and corrects for the extreme sensitivity to spatial heterogeneities of the single well converging test, but requires prior knowledge of presence or absence of matrix diffusion to give reliable estimate of transport parameters. Results of this study demonstrate that using a suite of different tracer designs is important to reduce the uncertainty in association with solving the inverse problem of tracer test interpretation to characterize transport in fracture rocks.