Discriminating effects of heterogeneity and matrix diffusion by alternative tracer designs

Technical Report · Wed Mar 01 04:00:00 EST 1995

DOI:https://doi.org/10.2172/70742· OSTI ID:70742

Tsang, Y Y.W.

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 can be 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 fractured rocks.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 70742
• Report Number(s): LBL--36831; ON: DE95012376
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AQUIFERS
FLOW MODELS
FLUID FLOW
FRACTURED RESERVOIRS
GEOLOGIC FRACTURES
PERMEABILITY
TESTING
TRACER TECHNIQUES