Overview and History of 3-D Modeling Approaches

This chapter focuses on layer-based modeling of the subsurface, which aims at a geometrically consistent, three-dimensional representation of various types of stratigraphic surfaces. The models contain structural or tectonic features appropriate to the user requirements and mapping objectives. Geologists initially undertook 3-D modeling to represent multi-dimensional objects with gridded values, or range of values, that reflected changes in their shape or value distribution over time. Between the 1950s and 1970s, several experimental approaches to displaying 3-D geological sequences more explicitly were developed. Subsurface geological models are being accepted as valuable resource-management and planning tools and have become mandated as part of official regulation and management environments. The chapter provides the discussion of the early modeling efforts for the Mahomet aquifer. Geological framework models typically map the distribution of major geologic units, which represent assemblages of rock types. 3-D interpolation methods are well suited to the creation of geological property models.