Geology sub-model provides fundamental support for Stratigraphy and the basic need to put names on geologic features. It does not cover the concept of representation, which allows grids, maps or drawings to show spatial relationships or characterize the properties of geologic features. To a lesser extent, the Geology sub-model allows for the description of structural elements such as faults and fluid contacts and the use of these features to outline reservoirs.
Geologic interpretations are constructed by establishing a framework of geologic features built of surfaces and the layers they bind. Geologic interpretation workflows vary according to purpose, individual and tools. Some geologists emphasize the geologic surface while others focus on the geologic layers. While these are not exclusive concepts in the work process some data representations may introduce an artificial division in the persisted object.
Geologic terminology is shown in the cross section given in Figure 1. It depicts a single stratigraphic layer bound by two stratigraphic surfaces. The layer is cut by a fault and contains a geologic facies exhibiting a channel shaped profile. The sand rich strata in the channel facies traps a hydrocarbon accumulation shown by the fluid contact which bounds a reservoir. A stratigraphic column provides names and characteristics for the geologic features shown.