Build the Structural Framework

The Skeleton First

Every model begins with the grid. Ogbon Field dips and is cut by a normal fault, so a simple box grid would slice across the dipping layers and smear rock together. The industry answer is the corner-point grid, whose cells slide along pillars to follow the dip and step cleanly across the fault.

Resolution Is a Budget

The first real decision is the cell count. More cells resolve the geology more finely but cost more to simulate, and the cost grows fast in three dimensions. Change the resolution in the figure: the field, the dip, and the fault stay the same, only the cell density changes. The volume in place barely moves, but the flow detail a coarse grid can carry does.

Honoring the Structure

Because the eight corners of each cell move independently along their pillars, the grid follows the steep dip and the fault offset without distorting the cells. Get this skeleton right and every later stage, the facies, the properties, the volumes, and the flow, sits on faithful geometry. Get it wrong and no amount of careful property modeling can repair it.