Process-Based Modeling of Reservoirs: Why Do It?

James K. Miller, Tao Sun, Hongmei Li, and Jonathon Stewart
ExxonMobil Upstream Research Company, Houston, TX

Recent advances will soon make constructing reservoir models by modeling the fundamental physical processes that formed them a reality. The need for improved methods for modeling remains critical. Current modeling practices cannot duplicate the natural order found in nature, neither can they reproduce the complex interactions of topography, flow, deposition and erosion. Rule-based parametric and pattern-matching techniques can come close, but no technique other than process-based modeling can provide the needed geologically realistic 3D volumes necessary for developing accurate rules or pattern training datasets. 3D Seismic can provide us some insight, but is limited in scale and cannot provide us direct information on the flows and processes that must have been present to lay down a given deposit. Outcrops and modern data are generally limited to 2D with poor expression of the 3D.

The process of building physics-based numeric models is complex; one has to determine initial conditions, solve for a multitude of unknown parameters, and retrace the full history of a reservoir from deposition through compaction, diagenesis, and structuring. However, recent advances in algorithm development, increased computer speed, new quantitative insights into the processes of flow and erosion, and better understanding of the chemical and hydrologic controls of diagenesis suggest that this complexity can be unraveled. Much technology still needs to be developed; modeling physics and honoring known data such as logs and seismic remains extremely challenging.

We will show examples of a span of application of process-based models, ranging from developing new insights into stratigraphic processes, to extraction of patterns and statistics for rule-based and geostatistical modeling, through to full physics simulation of the erosion and deposition of a reservoir.

AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery