Double-porosity tracer-test analysis for interpretation of the fracture characteristics of a Dolomite formation
Hydraulic and tracer testing studies have been performed as part of the regional hydrologic characterization of the Waste Isolation Pilot Plant (WIPP) site in southeastern New Mexico. The interpretation of hydraulic tests and tracer tests from a number of locations has indicated the importance of the double-porosity concept in the interpretation of both the hydraulic and solute-transport characteristics of the fractured dolomite under study. A convergent-flow tracer test conducted in the Culebra Dolomite Member of the Rustler Formation at the WIPP site was analyzed using a double-porosity flow and transport model. The transport of conservative tracers from each of the tracer-addition wells was simulated using the double-porosity flow and transport model SWIFT II. The simulation model accounts for advective-dispersive transport in the fractures and diffusive transport in the matrix. Calibration of the tracer-breakthrough curves included conducting a sensitivity analysis on the important parameters: diffusion coefficient, tortuosity, matrix porosity, fracture porosity, effective matrix-block size, pumping rate, initial tracer input distribution, and distance between pumping and tracer-addition wells. Calibration of the tracer-breakthrough curves resulted in longitudinal dispersivities from 5 to 10% of the flow path length (well-separation distance), a fracture porosity of 0.002, and effective matrix-block sizes of 0.8 ft to 3.9 ft. Even though these estimates of fracture porosity and effective matrix-block size are specific to the location of the tracer test, they provide an initial estimate on which to base predictions of the regional transport of solutes in the Culebra dolomite.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA); Intera Technologies, Inc., Austin, TX (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6900253
- Report Number(s):
- SAND-87-0068C; CONF-870252-4; ON: DE87005876
- Resource Relation:
- Conference: NWWA conference on solving ground water problems with models, Denver, CO, USA, 10 Feb 1987; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
DOLOMITE
GEOLOGIC FRACTURES
POROSITY
WIPP
SITE CHARACTERIZATION
GEOLOGY
HYDROLOGY
NEW MEXICO
TRACER TECHNIQUES
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
FEDERAL REGION VI
FUNCTIONAL MODELS
GEOLOGIC STRUCTURES
ISOTOPE APPLICATIONS
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERALS
NATIONAL ORGANIZATIONS
NORTH AMERICA
NUCLEAR FACILITIES
OXYGEN COMPOUNDS
PILOT PLANTS
RADIOACTIVE WASTE FACILITIES
UNDERGROUND FACILITIES
US DOE
US ORGANIZATIONS
USA
052002* - Nuclear Fuels- Waste Disposal & Storage
580100 - Geology & Hydrology- (-1989)