GRID

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 Cirrus, 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

Cirrus can also do local grid refinements (LGR). However, to define wells, faults, or different properties within an LGR there are some differences with the standard approach, see Local Grid Refinement (LGR) for more details.

More details on the eclipse-style grids are given in:

• GRDECL grids
• Local Grid Refinement (LGR)

Other grid formats are available for advanced Cirrus users:

• Structured and Structured Cylindrical

• Unstructured Explicit