iTOUGH2 relies on the TOUGH2 code for the solution of the forward problem. TOUGH2 is a general-purpose numerical simulator for multiphase fluid and heat flow in fractured-porous media, with applications in geothermal reservoir engineering, nuclear waste disposal, and environmental contamination problems.
The TOUGH2 family of codes consists of a number of fluid property and process modules. A list of available modules as well as recent code developments are maintained on the TOUGH2 web site. The core of iTOUGH2 contains slightly modified versions of some of the TOUGH2 modules (see table below). Furthermore, some features have been added to all modules (printout control, secondary mesh, element-by-element properties, user-specified boundary conditions, new relative permeability and capillary pressure functions.) These modifications are described in the iTOUGH2 Command Reference.
A list of TOUGH2 modules that are currently adapted for use with iTOUGH2 can be found on the TOUGH Licensing & Download page.