Framework QC and Why It Matters

Check the Skeleton First

The framework is the one part of the model that every later step inherits: facies and properties are simulated on it, volumes are summed over it, and the flow simulator solves between its cells. A defect here propagates everywhere, so the framework is quality-checked before any property is added. The most damaging defect is crossing horizons. Add a pick error in the widget and watch the top horizon dip below the base: where they cross, the zone has negative thickness.

Why Negative Thickness Is Fatal

A negative thickness means negative cell volumes, and negative volumes are nonsense: they corrupt the in-place calculation (a region that subtracts oil) and routinely crash the flow simulator, which cannot integrate a cell with no positive volume. There is no property model good enough to rescue a framework with crossing horizons; the pick has to be corrected first. The fix is geological: re-pick the horizon so it stays above the one below, honoring the seismic and the wells.

The Wider Checklist

Crossing horizons are the most obvious failure, but a full framework QC covers more: fault throws consistent between intersecting faults, no gaps or overlaps where the grid meets a fault, cell orthogonality good enough that the flow solver stays accurate, and layer thicknesses sensible. Passing these checks is the gate between building the skeleton and populating it. With a clean framework in hand, the next chapter turns to designing the grid itself for resolution and flow.