The stratigraphic model

An integral part of the application's modeling workflow is defining a stratigraphic model. The stratigraphic model links two important aspects of geological modeling:

The stratigraphic model should be constructed early in the modeling process, as a collaborative tool to ensure all disciplines are aligned on how their data will be incorporated into the geological model. Stratigraphic correlation establishes connectivity in a reservoir model. Also, the stratigraphic model influences the fluid model definition and the structural model building sequence. After the stratigraphic model is defined, it determines how units will relate to each other vertically as well as laterally, once they are constructed in 3D in the structural model.

A characteristic element of the stratigraphic model in JewelSuite Subsurface Modeling is its use of hierarchy in the form of stratigraphic ‘levels’. The hierarchical concept supports a set of parent child relationships, where one parent can have multiple children, but a child can only have one parent (see image further below, where an example is given for the North Sea Brent Group). The hierarchical concept of the stratigraphic model has clear advantages during the various modeling stages:

Hierarchical levels in the stratigraphic model support the lithostratigraphic concept commonly known as the Group-Formation-Member relationship, which is relevant in most reservoir modeling studies, where rocks are described using their gross lithological characteristics and named according to their rank in this formal hierarchy. In many reservoir field studies, a typical hierarchical stratigraphic scheme combines the regional (group and/or formation) stratigraphy with local production allocation and reservoir modeling zones at deeper levels. Irrespective of the approach, the stratigraphic model forms the framework for various types of modeling purposes, such as structural models, fluid flow models or geomechanical models.