Abstract: Modeling the Unexpected: a New Approach to 3D Reservoir Modeling Cuts Reaction Time in Fast-Track Developments

GUTTERIDGE, PAMELA, and DAVID GAWITH*

How fast can a subsurface team react if new well results invalidate the reservoir model? In fast-track developments there is not time to go back and start again.

Many 3-D reservoir models are essentially engineering models, containing little geology; they do not easily adapt to unexpected events. Geological modeling makes it easier for the subsurface team to think about alternative reservoir models, because this is an interpretative process, not simply manipulation of data. A lot of attention has been paid to rapid re-building of geological models, creating a new model quickly to take account of new data, but it can still take a month or more to make new performance predictions.

However, a subsurface team can react much faster to new information if it matches an alternative interpretation which they have already evaluated. In other words, the best trick is to have modeled already the situation which the new data indicates.

Through creative application of the latest modeling technology, the radical exists simultaneously in many forms, corresponding to different interpretations of the available data. This means that the team can model all the alternatives, rather than a single "most likely" reservoir description. When new data arrives, it changes the relative probabilities of the model versions and allows us to make new predictions of field performance straight away. The team is on top of the situation and the asset manager has technical support for quick decisions.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria