The technical and economic challenges of exploring and producing in deepwater environments require that risk and uncertainty be reduced as much as possible. One of the major contributors to uncertainty – and therefore risk – is creating a sound structural framework. Sophisticated geostatistical techniques are commonly used to create facies and petrophysical models which are used for analyzing uncertainty and making reservoir management decisions, but the underlying structural frameworks often do not correctly portray the true structure. Current methodologies have limitations to the types of fault intersections, the number of faults that realistically can be modeled, and/or the type of grid that can be generated from the reservoir model.
The structural framework is often a compromise between the actual structure and what the modeling system allows, particularly in areas with large numbers of Y-intersections, low angle faults, or reverse faults. We have developed a new technique for structural framework building that takes a unique approach to constructing the initial fault model, where fault relationships and intersections are easily defined and controlled.
This technique does not have limitations to the types of fault intersections nor to the number of faults which may be included in a reservoir model, and provides the tools to build a reservoir grid using these complex fault intersections. When the structural framework more accurately represents the interpretation, subsequent calculations such as reserve estimates, analysis of structural uncertainty, or well placement can be made with more confidence.
The simplicity of building and editing the fault relationships, creating the stratigraphic model, and building the reservoir grid means that an asset team can easily update a model, test different interpretations, and use the model for both geologic and engineering applications.