Capturing Multi-Scale Geologic Heterogeneity With Logical Rules in Sketch-Based Reservoir Modeling

Abstract

Conventional reservoir modeling workflows are not optimized for rapid prototyping and testing of reservoir models. A common approach to prototyping in other engineering and design fields (e.g. aeronautics) is to use computer-aided design or sketch-based interfaces and modeling (SBIM). SBIM is used to develop geometrically complex 3D models quickly, in order to test an underlying concept and investigate its implications. A similar, experimental philosophy for reservoir modeling is not favored by conventional workflows, which can be laborious to use, emphasize unreasonable accuracy, and require a high level of user expertise.

We present an alternative approach to reservoir modeling using an intuitive, sketch-based system. Our SBIM workflow uses logical rules that define how stratigraphic and structural surfaces can interact, thereby allowing the rapid creation of geologically sound models by non-expert modelers. Users are able to create a variety of models for a number of purposes, including to capture combinations of reservoir heterogeneity of different types and scales, to investigate a range of interpreted geologic scenarios, and/or to test the impact of uncertainty in geologic interpretation.

Our workflow is particularly applicable to capturing reservoir heterogeneity because the underlying logical rules are scale- and process-independent. For example, the same rules can be used at successively smaller scales to create basin-fill stratigraphy, positioning of architectural elements within a reservoir unit, and cross-lamination within a bed. This allows reservoir heterogeneity to be captured at the level of geologic detail required by the modeler, and for the level of modeled geologic detail to be increased or decreased in a straightforward, geologically plausible manner.

We present two example models to demonstrate the flexibility and applicability of the logical rules and SBIM workflow. One model is of a deepwater slope channel complex (Pleistocene Rakhine Basin, Myanmar), and the other model is of carbonate platforms of complex geometrical configurations that varied through time (Miocene Luconia Province, Sarawak). Both models can be generated and modified quickly, to accurately capture stratal architectures and facies distributions in these different geologic settings, using the same logical rules and workflow. With this approach it is possible to explore multiple scenarios for a 3D reservoir model in a matter of hours or days rather than weeks or months.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018