Improved Variogram Models for More Realistic Estimation and Simulation

Geostatistical models often require a variogram or covariance model for kriging and krigingbased simulation. Next to the initial decision of stationarity, the choice of an appropriate variogram model is the most important decision in a geostatistical study. Common practice consists of fitting experimental variograms with a nested combination of proven models such as the spherical, exponential, and Gaussian models. These models work well in most cases; however, there are some “shapes” found in practice that are difficult to fit. Greater flexibility is available through the application of geometric and spectral corrected variogram models.