Corner-point grid

In geometry, a corner-point grid is a tessellation of a Euclidean 3D volume where the base cell has 6 faces (hexahedron).

A trivial example of a Corner-point grid with only two cells.

A set of straight lines defined by their end points define the pillars of the corner-point grid. The pillars have a lexicographical ordering that determines neighbouring pillars. On each pillar, a constant number of nodes (corner-points) is defined. A corner-point cell is now the volume between 4 neighbouring pillars and two neighbouring points on each pillar.

Each cell can be identified by integer coordinates ${\displaystyle (i,j,k)}$, where the ${\displaystyle k}$ coordinate runs along the pillars, and ${\displaystyle i}$ and ${\displaystyle j}$ span each layer. The cells are ordered naturally, where the index ${\displaystyle i}$ runs the fastest and ${\displaystyle k}$ the slowest.

Data within the interior of such cells can be computed by trilinear interpolation from the boundary values at the 8 corners, 12 edges, and 6 faces.

In the special case of all pillars being vertical, the top and bottom face of each corner-point cell are described by bilinear surfaces and the side faces are planes.

Corner-point grids are supported by most reservoir simulation software, and has become an industry standard.