Kriging Versus Simulation

Two Different Goals

Kriging and simulation start from the same wells and variogram but answer different questions. Kriging asks for the single best estimate and returns a smooth map. Sequential Gaussian simulation asks for a realistic rock and reproduces the full variogram and histogram, adding back the variability kriging averaged away.

Why Smoothness Is Wrong for Flow

The smooth kriged map underestimates the extremes: it has no high-permeability streaks and no tight barriers, only gentle gradients. But flow is controlled by exactly those extremes. Running a simulator on a kriged map gives the wrong dynamics. A simulated realization, rough and full of connected highs and lows, behaves like real rock.

One Map or Many

The price of realism is non-uniqueness: every seed gives a different, equally valid realization, so we run many. Kriging is right when you want one best estimate of a smoothly varying quantity; simulation is right when heterogeneity matters or you need to quantify uncertainty, which is almost always the case for flow modeling.