Abstract: 3-D Petroleum Systems Modeling - Expectations and Reality

Wygrala, Bjorn; Thomas Hantschel and Gary Muscio - Integrated Exploration Systems (IES)

Methods commonly employed in 3D petroleum migration modeling include a) pseudo-3D simulations of buoyancy driven flow along surfaces (map-based models), and b) fully integrated 3D physical models of thermal, pressure, generation and migration histories.

The fundamental advantage of map-based models is their fast, high-resolution processing and total simulation times rarely exceed several tens of minutes. The major disadvantage is their 1-dimensionality which can lead to inaccurate temperature and pressure calculations, and therefore to insufficiently well-defined boundary conditions for the migration models. Seal definitions are often based on arbitrary assumptions as only a full 3D model can calculate the relationships between capillary, buoyancy and pore pressures and other determining factors. Map-based models are an essential part of any risk analysis, but users must be aware of their limitations.

Full 3D models offer physically perfect solutions but processing times are long, and simplified models must be used in order to provide results in realistic time spans, i.e. within hours to several days on high-end workstations. Code parallelization and the use of workstation clusters has narrowed the gap, but user expectations have been formed by high-resolution, map-based models and they cannot be met by the full 3D models, which appear oversimplified and coarse.

However, recent developments in 3D data models and in the way that the different model types can be linked provide a way to bridge this gap. Both methods provide essential benefits and the improved integration now enables users to efficiently deploy them both.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil