Variograms and Spatial Continuity
The variogram is the workhorse of spatial statistics: it measures how quickly a property decorrelates with distance. Learn lag binning, directional variograms, anisotropy, and model fitting on interactive datasets where you control the geology.
20 interactive sections across 1 book
Geostatistics
- Covariance, correlogram, and variogram, three views of the same thing
- h-scatterplots and lag binning
- Isotropic and directional variograms
- Nested structures and additive sills
- Permissible model families (spherical, exponential, Gaussian)
- Universal kriging and kriging with external drift
- Anisotropic ellipsoids and the search ellipse
- The kriging variance, what it means and what it doesn't
- Capstone 1: Clastic shelf reservoir characterization
- Fitting strategies: by eye, by WLS, by likelihood
- Nugget effect and short-scale variability
- Ordinary kriging and the unbiasedness constraint
- Simple kriging from first principles
- Calibration of the kriging variance
- Anisotropy: range, sill, geometric vs zonal
- Indicator variograms
- Robust variogram estimators
- What declustering changes downstream
- Cokriging with secondary data
- Debiasing checks and conditional bias