Kriging and Simulation in Presence of Stationary Domains: Developments in Boundary Modeling

Abstract

Perhaps the most critical decision in geostatistical modeling is that of choosing the stationary domains or populations for common analysis. The boundaries between the stationary domains must be modeled with uncertainty. The correlations and trends across these boundaries must be used in modeling. Interpolating a distance function is a useful method for modeling boundaries with uncertainty. The current implementation of distance function boundary modeling with uncertainty requires expensive calibration with simulated data and numerous reference models to ensure unbiasedness and fair uncertainty. A method for using the available data to calibrate the distance function is proposed which greatly reduces the calibration expense. The nature of the boundaries between stationary domains must be considered. Boundaries can be hard or soft. The boundary nature must be accounted for in the modeling. A contact plot is a useful tool for identifying the nature of the grade transition across a boundary. Guidelines for determining the nature of a boundary from a contact plot are suggested. With the location of the boundary defined and the nature of transition across the boundary determined, the next step is to model the grades in a manner that accounts for the boundary information. The resulting models should reproduce the boundaries of the stationary domains and reproduce the nature of the boundary at the boundary location.