The grid of the computational model is defined by the GRID block, which specifies the type of discretisation to be used. Grid may define a regular grid directly, or select an external file where the grid data is stored.
Various types of meshes can be defined using the TYPE keyword. A common grid type for reservoir simulation is GRDECL, in which the grid is defined using a number of Eclipse keywords in a named file. The GRDECL format is recommended for reservoir simulations in PFLOTRAN, as it is the only one that supports modeling of wells using the keyword WELL_DATA.
An example of use of the GRDECL grid format is given below:
GRID TYPE grdecl spe10.grdecl END
More details on the eclipse-style grids are given in:
Other grid formats are available for advanced PFLOTRAN users: