RELEASABLY LOCKED DEBRIS BARRIER FOR A SUBTERRANEAN TOOL

摘要

An articulated debris barrier folds on itself to extend radially to span a surrounding annular gap when the tool associated with it is set. The debris barrier can be used with a packer or bridge plug. The set position of the packer or plug is locked and another lock holds the extended position of the debris barrier. The debris barrier lock can be a snap ring that extends into a groove brought into alignment with it during the setting. Alternatively the lock for the debris barrier can be a body lock ring. In either case, release and retrieval of the packer or plug involves undermining of the locking feature for the debris barrier so that the debris barrier can extend while retracting from the borehole wall so that the barrier and the associated packer or plug can be removed together.