Definition(s)
Annular Packers and Seal Rings
Mechanical barrier devices with flexible, elastomeric sealing elements that can be run into a well on casing or liners for application as: a) annular element installed between an inner and outer pipe or between a casing and openhole formation to seal the annulus, b) annular seal rings installed on the inner pipe string to seal the micro-annulus and voids formed between the cement sheath and the inner pipe string.
Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards