Continuous Expandable Backup Ring for a Seal with Retraction Capability

摘要

The extrusion barrier for a sealing element for a packer or bridge plug is energized when set to store a retractive force that can be deployed when the packer or plug is released. The structure is a coiled spring that has gaps in the run in position and has a relaxed diameter smaller than the borehole or surrounding tubular dimension. When the packer is set a cone acts in conjunction with the spring to compress the coils together into contact while increasing the diameter to bridge an annular gap to act as an extrusion barrier. In the set position there is a restorative potential energy force that when the spring is allowed to relax retracts the shape back to the run in shape for removal of the packer or plug. Some of the trailing end coils are of a smaller diameter so that the structure can be clamped there for forcible axial movements in opposed directions.

主权项

1. A retrievable apparatus for forming a seal against a borehole wall, comprising:a mandrel;
a sealing assembly on said mandrel operable between a run in and a set position for sealing against the wall and release from the wall; an anti-extrusion assembly on said mandrel operable between a run in and a set position, said assembly storing potential energy force in said set position that acts in a direction to move said anti-extrusion assembly toward said run in position when said force is released.