Stratigraphic rule-based reservoir modeling

Abstract

Abstract Stratigraphic rule-based modeling methods approximate sedimentary dynamics to generate numerical descriptions of reservoir architecture and the spatial distribution of petrophysical properties. A few intuitive rules included in a reservoir model construction workflow are shown to render realistic reservoir heterogeneity, continuity, and spatial organization to petrophysical property distributions that are difficult to obtain using conventional reservoir modeling methods. These rules may be inferred from mature reservoirs, surface and subsurface datasets, and process-based models. Examples include confinement, meander, compensation, and healing rules. By incorporating stratigraphic rules that relate to the underlying geological processes in temporal sequence, rule-based modeling methods offer more realistic representation of inferred reservoir heterogeneity beyond conventional geostatistical reservoir modeling approaches. These include variogram-based, multiple point-based and object-based approaches that rely on a limited set of spatial statistics to describe the products of geological processes. Moreover, since these methods operate within a geostatistical framework, uncertainty can be explored by varying geologically meaningful parameters over multiple scenarios and realizations whilst maintaining consistency with input data constraints and applied to reservoir modeling studies within standard workflows. Rule-based modeling methods enable a variety of applications, including use: directly as reservoir models, as a source of reservoir model input statistics such as variograms and training images, and as a numerical analog laboratory to explore relationships between data, model choices and forecasts. Challenges remain, such as reliability of emergent features, alignment to grid framework, and feasibility for broad application. Despite challenges, rule-based methods can offer uplift when the natural facies continuity patterns and their corresponding petrophysical properties are critical to support decisions in reservoir modeling projects.