Reservoir Geomechanics - Implications for Reservoir Fracture Permeability and Fault Seal Integrity

C. Barton¹ and D. Moos^2
1GeoMechanics International, Menlo Park, CA, [email protected]
²GeoMechanics International, Menlo Park, CA, [email protected]

A field-specific geomechanical model serves as a platform for dramatically reducing costs and increasing production over the life of a field. The information contained in a geomechanical model makes it possible to reduce drilling costs and production losses through field-wide well planning that can optimize production and minimize risk. A significant value of the geomechanical model is its application to the efficient exploitation of fractured and faulted reservoirs.

A growing body of evidence reveals that in many fractured reservoirs the most productive fractures are those that are optimally aligned in the current stress field to fail in shear. Thus, it is necessary both to obtain knowledge of the stress magnitudes and orientations and of the distribution of natural fractures to determine the optimal orientations for wells to maximize their productivity. The best well intersects the maximum number of stress sensitive fractures. Applying geomechanics and the reservoir fracture distributions to model shear-enhanced permeability as the mechanism for reservoir production appears to be a promising improvement to existing reservoir flow models.

Fault-trap integrity is also strongly influenced by the state of stress resolved on reservoir bounding faults. The ability of a fault to support a hydrocarbon column is influenced by the principal stress directions and magnitudes, and by fault geometry. Through careful construction of a geomechanical model the risk of encountering breached reservoirs in exploration and appraisal wells can be quantified.

AAPG Search and Discovery Article #90088©2009 Pacific Section Meeting, Ventura, California, May 3-5, 2009