reservoir geomecanics

410 Reservoir geomechanics
Figure 12.15. Cumulative production from a hypothetical reservoir with a single well. One
simulation represents compaction using constant compressibility throughout production. When
compaction drive (porosity loss due to depletion) is considered, the cumulative production from
this reservoir is increased significantly. However, the loss in permeability associated with a loss in
porosity reduces the reservoir productivity to some degree, depending on the severity of
compaction-induced permeability loss.
permeability (upper bound) on the estimated recovery. The trade-off between porosity
changes and permeability changes has significant implications for the determination of
the recovery rate and the overall exploitation scheme for the reservoir and will affect
critical decisions such as the need to drill additional wells.
Viscoplastic deformation and dynamic DARS
One of the limitations of traditional end-cap models, such as the modified Cam-Clay
described in the previous section, isthat the models only describe materials with a
static, time-independent yield surface. For materials with significant time-dependent