SWIFT-98 Order No: TPS 41

Price: $395

SWIFT-98 is a fully transient, three-dimensional model which simulates the flow and transport of fluid, heat (energy), brine, and radionuclide chains in porous and fractured geologic media. The primary equations for fluid, heat, and brine are coupled with fluid density, fluid viscosity, and porosity. Steady-state options are available for the fluid and brine equations, and both Cartesian and cylindrical coordinate systems may be used. However, the latter system is restricted to two-dimensional, r-z simulations. Both dual-porosity and discrete-fracture conceptualizations may be considered for the fractured zone. Migration within the rock matrix is characterized as a one-dimensional process.

SWIFT - 98 is comprised of the four transport processes: fluid, heat, brine, and radionuclide chains. For porous media, only the global (three-dimensional) process simulator is used. For fractured media, the global process simulator is used for the fractured media, and the local (one-dimensional) process simulator is used for the rock matrix.

Basic Assumptions and Characteristics

  • Single-phase fluid flow governed by Darcy's law
  • Three-dimensional transport in the global system, and one-dimensional transport in the local rock-matrix subsystem
  • Local rock matrix may be characterized by either prisms or spheres
  • Linear variations in porosity and fluid density with respect to the dependent variables
  • Viscosity is dependent on temperature and brine concentrations only
  • Nonlinear isothermal equilibrium adsorption (Freundlich or linear)
  • Injection wastes are miscible with the resident fluids
  • Confined or unconfined aquifer (transient or steady-state free water surface)
  • Hydraulic and thermal conductivities may be heterogeneous and/or anisotropic
  • Longitudinal and transverse dispersivities may vary throughout the domain
  • Variable rock compressibility (storativity)
  • Dual or simulataneous discretization

    • Discretization is performed by the finite-difference method using centered or backward weighting in the time and space domains. Matrix solution is performed either by Gaussian elimination or by two-line successive overrelaxation.

    A variety of boundary conditions and source terms may be invoked for both the porous and fractured media. These include:

  • Prescribed pressure (head), temperature, and brine concentration
  • Prescribed flux of fluid (water), heat, brine, or nuclide mass
  • Wellbore injection/production submodel subject to pumping constraints
  • Aquifer influence function (i.e., Carter-Tracy infinite reservoir)
  • Dual porosity domain extension
  • Waste-leach radionuclide submodel for waste repository nuclides and heat
  • Freewater surface with recharge

    • SWIFT can be applied to a variety of groundwater problems, ranging from simple well flow to complex transport analysis.

  • Deep-well injection of hazardous waste; isothermal/nonisothermal, constant/variable density
  • Seawater intrusion
  • Optimization of well fields to reduce intrusion and upconing
  • Prediction of hazardous waste migration
  • Well performance and pumping test analysis
  • Complex variable-block elevation and thickness data (input via a separate binary file)

    Postprocessor Interface (UNSWIFT) Contour maps of pressure, temperature, brine, or concentration in any window in any plane can be quickly processed directly into uniformly-spaced grid files for the SURFER contouring software. STLINE Particle Tracking allows transient flowpath evaluation of streamlines and export to SURFER as lines or posted symbols.

    SYSTEM REQUIREMENTS:

    Pentium with 32+ MB RAM, Lahey LF90, Version 4.5, SURFER for postprocessing

    Custodian: GeoTrans, Inc., Sterling, VA.