Honoring Dip and Structural Complexity

The Problem with Box Grids

A simple box, or Cartesian, grid has horizontal cells stacked in regular rows. That is fine for a flat reservoir, but real reservoirs dip and fold. Where the layers dip, a horizontal cell slices across them, capturing part of a sand and part of a shale in the same cell. The model then assigns that cell a single averaged porosity and permeability, smearing away the very layering that controls how fluids flow. The widget makes this visible: raise the dip and the box grid fills with mixed cells.

How Corner-Point Grids Follow the Structure

The corner-point grid solves it by letting the cell edges follow the geology. Because the eight corners of each cell slide independently along their pillars, the cell tops and bases can parallel the dipping layers, so each cell stays inside a single layer. Toggle the grid type in the widget: the corner-point cells shear to follow the dip, and the mixing drops to zero. This is why corner-point geometry, not the simpler box grid, is the industry standard for anything but the flattest reservoir.

Complexity Raises the Stakes

The steeper the dip and the more faults and folds the structure carries, the more a box grid distorts and the more a corner-point grid earns its keep. Steeply dipping flanks, overturned folds, and reverse faults push even corner-point grids to their limits, and are where modern unstructured and cut-cell grids come in. For the great majority of reservoirs, though, a well-built corner-point grid that honors the dip and the faults is exactly what keeps the properties and the flow faithful to the geology.