Parameters Estimated by iTOUGH2

In general, any input parameter for the TOUGH2 simulator can be estimated using iTOUGH2, provided that data of sufficient sensitivity are available. The parameters include hydrogeologic and thermal properties, initial and boundary conditions, some geometric features, as well as shifts or lags in the data. A list of parameters currently implemented in iTOUGH2 is shown below. Furthermore, an interface routine is provided in which users can specify their own parameter types.

Most of the parameters refer to one or more rock types defined in TOUGH2, but they may also be associated with grid blocks, sink/sources, parameters of the meshmaker utility, or default properties. One can estimate individual parameters or groups of parameters of the same type. iTOUGH2 estimates either the value of a parameters, its logarithm or a scaling factor. Prior information about the parameter can be provided, along with lower and upper bounds.

The following is a partial list of available parameter types (check Command Index for a complete list):

  • Anisotropic absolute permeabilities
  • Any parameter of the relative permeability functions
  • Any parameter of the capillary pressure function
  • Initial conditions
    • Initial pressure
    • Initial saturation
    • Initial temperature
    • Initial mass fraction
  • Boundary conditions
    • Boundary pressure
    • Boundary saturation
    • Boundary temperature
    • Boundary mass fraction
    • Time-dependent or constant sinks and sources
  • Porosity
  • Rock compressibility
  • Heat capacity
  • Thermal conductivity
  • Klinkenberg factor
  • Distribution of pumping rates within a well cluster
  • Fracture aperture assuming parallel plate model
  • Productivity index for wells on deliverability
  • Bottomhole pressure for wells on deliverability
  • Fracture spacing for MINC meshes
  • Lag in the data
  • Drift in the data
  • Parameters of the SELEC block
  • IFS parameters
  • Grid scaling factor
  • Rockmechanical parameters (if iTOUGH2-ROCMECH)
  • Geostatistical parameters and pilot point values (if iTOUGH2-GSLIB)
  • GeoT parameters (if iGeotT)
  • User-specified parameters