Downhole locking apparatus

摘要

A locking apparatus for positioning a well tool within a subterranean well bore and comprising a primary locking member attached to the well tool; a nipple incorporable in a subterranean well conduit; and running and retrieving tools for positioning the lock member is disclosed. The lock has a no-go shoulder for initially positioning the lock adjacent the nipple and radially expandable locking dogs for carrying both upwardly and downwardly directed forces upon full expansion thereof after the no-go shoulder has been disengaged. At least two interlocking members disengagable only by separate manipulations maintain the locking dogs in a radially expanded fully engaged position. A retrieving tool having a rotational alignment means to position the tool relative to the lock is used to separately manipulate the interlocking members and to pull the disengaged lock from the well.