IMPLICIT GEOLOGICAL MODELING WITH LOCALLY VARYING ANISOTROPY

Geological structures such as folds, veins, and channel systems often have complex curvilinear geometry. Generating 3D geological models featuring these structures is difficult as drillhole data are typically sparse and preferentially sampled. Furthermore, most implicit modeling techniques rely on interpolation methods based on a single global anisotropy model, which is inappropriate for modeling complex geological structures from sparse drillhole data. Inaccurate geological models may lead to poor mineral resource estimates and groundwater flow models. Locally varying anisotropy is a spatial modeling framework which enables interpolation of complex structures based an anisotropy field that locally describe the direction of geological continuity across the modeling domain using non-Euclidean distances. In this work, an algorithm for 3D implicit geological modeling with locally varying anisotropy is proposed. Locally varying anisotropy fields are inferred based on interpolation of available structural data derived from drillhole samples. This information is subsequently used to construct an undirected weighted graph describing the spatial connectivity and geological distances between the interpolation grid nodes and the conditioning data. Multiple-category geological models are generated by interpolation using the signed distance function method. Adaptations for modeling folded layers and vein systems are illustrated with synthetic examples.