COMPENSATING FOR ESTIMATION SMOOTHING IN KRIGING

Smoothing is a characteristic inherent to all minimum mean-square-erro r spatial estimators such as kriging. Cross-validation can be used to detect and model such smoothing. Inversion of the model produces a new estimator-compensated kriging. A numerical comparison based on an exh austive permeability sampling of a 4-ft(2) slab of Berea Sandstone sho ws that the estimation surface generated by compensated kriging has pr operties intermediate between those generated by ordinary kriging and stochastic realizations resulting from simulated annealing and sequent ial Gaussian simulation. The frequency distribution is well reproduced by the compensated kriging surface, which also approximates the exper imental semivariogram well-better that ordinary kriging, but not as we ll as stochastic realizations. Compensated kriging produces surfaces t hat are more accurate than stochastic realizations, but not as accurat e as ordinary kriging.