It is well recognized that structural and stratigraphic frameworks are the geologic features that have the highest impact on the flow simulation results. Great advances are being made in modeling complex structural scenarios with either truncated or stair-step grids. However some key stratigraphic features are commonly modeled with simplified geometries (e.g. use of simple layering styles) that are limited in their ability to represent stratigraphic concepts. Due to high geometric complexity of the combined structural and stratigraphic assumptions, simulation grid is bound to further simplify them and thus lose the ability of recapturing geologic concepts and closing the feedback loop of the reservoir modeling and simulation workflow.

Preserving sound structural and stratigraphic concepts from geologic modeling all the way to flow simulation is critical for reliably predicting flow streams. In this paper we propose an approach to address full geometric complexity of geologic frameworks' description by integrating stratigraphic modeling with the generation of truncated simulation grids. We start by defining a continuous volume (e.g., so called “depositional space”) created by removing discontinuities in the original faulted model according to a suitable geometric criterion. Stratigraphic modeling of interfaces and regions, such as channels or sand lobes, shale drapes or high permeability streaks, is carried out in this continuous space. Stratigraphic concepts are represented in this space by volumetric functions including, in particular, an indicator function to designate each different layer or stratigraphic region. After the stratigraphic models are created for all reservoir zones, we generate a grid, which can be either geologic model grid or simulation grid, directly in the original faulted domain. The grid is built honoring both stratigraphic region definition from the “depositional space” (through layer reconstruction) and structural framework of the faulted domain (through truncation). We compare the set of technical challenges our approach presents with other known truncated grid generation techniques.

Examples of the grids adapted to both structural and stratigraphic frameworks according to the proposed methodology are included and flow simulation results are demonstrated on these simulation grids. Examples are based on common geologic environments with a range of complexity of stratigraphic frameworks, e.g., from shoreface to lobes and channelized clastic environments.

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