A part of subsurface reservoir which is not hydrodynamically connected to other parts of subsurface reservoirs.

Sometimes this definition extends to the cases when reservoir units may have the hydrodynamic connection but very weak or happening far from the location where they have been identified.

For example, away from the well where the reservoir units have been delineated.

In other words, the subsurface reservoirs may contain few isolated from each other reservoir units, which in some cases may happen to have indirect communication.

See Also

Petroleum Industry / Upstream / Subsurface E&P Disciplines / Petroleum Geology / Reservoir