US Patent 9145755 Sealing annular gaps in a well

A well tool for sealing against a wall of well includes an elongate mandrel. A seal assembly encircles the mandrel and can change between an unset state and an axially compressed set state. The seal assembly includes an annular elastomer seal element configured to radially deform into contact with the wall of the well in the set state. An annular anti-extrusion ring is included to compress the seal element and form a containing space with a garter spring embedded in the seal element. The garter spring is embedded in the seal element adjacent the axial end of the seal element and configured to span the gap between the anti-extrusion ring and the wall of the well in the set state. The containing space can prevent the seal element from excessive deformation.