Building Structural Frameworks in Complexly Faulted Reservoirs

Hoffman, Karen S.¹, John W. Neave², Erik H. Nilsen² (1) Roxar, Inc, Houston, TX (2) Roxar, Inc,

As exploration and production expands into ever more complex structural settings, it is becoming increasingly critical to create robust and accurate reservoir models for optimum exploitation. Sophisticated geostatistical techniques are commonly used to create facies and petrophysical models which are used for 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 we call the fused fault block method. Our method 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. Our unique approach to 3D gridding of thrust or reverse faults allows staircasing of these faults while maintaining the correct IJK indexing and does not require any modification of the faults. 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