Print this pageObject-Based Modeling of Deep-Water Depositional System Reservoirs
LARUE, D. K., and T. A. JONES
Object-based facies models (OBMs) are constructed by stochastically distributing in three dimensions idealized facies elements (objects) that have well-defined geometries. Typical OBMs simulate fluvial channels and splays, but other geological objects or forms have been modeled. The resulting 3-D geological model contains geological features and shapes that are distributed according to sequence-stratigraphic and other geological rules and are conditioned with available data. Benefits of using OBM include the following: (1) the result is a model of connectivity between objects and continuity within objects; (2) the resulting 3-D model visually resembles "natural" geology, making it easier to incorporate or demonstrate geologic concepts or features; and (3) because the model attempts to capture true geological relationships, the resulting OBM can be stratigraphically validated after construction. That is, the model can be queried to test for adherence to geological observations, such as length scales of barriers or baffles to flow.
We have developed techniques to incorporate key stratigraphic and sedimentologic features into deep-water depositional models. These include the following: (1) Gross internal stratigraphy -- two types of internal fan stratigraphy were modeled using proportional gridding and top-surface- referenced gridding: (2) Sequence-stratigraphic architecture- several high-frequency sequences were modeled, each characterized by an abrupt erosional base and overlain by a retrograding succession of channel deposits; (3) Channel distribution-channels radiated from a canyon area; (4) Channel types-meandering and braided channel deposits were modeled; (5) Down-fan trends- channel deposits were modeled that widen and thin in a down-fan direction until attaining a stochastically- determined zero edge; (6) Other facies-levee and splay deposits and within channel heterogeneities were also modeled. Such object-based geologic modeling of deep-water reservoirs is ideally suited for making preliminary estimates of reservoir performance. We illustrate the benefits of object-based modeling with several deep-water depositional system reservoirs.