Positive locating expendable plug

Abstract

This invention relates to an expendable tool, such as a plug assembly, which may be locked within a tubular member, such as a packer assembly, located within a well casing, and a method of locating and releasing same. The plug assembly comprises a main housing adapted to support a plurality of circumferentially spaced, radially retractable locking segments. A longitudinally extending mandrel is slidably mounted within the housing and is axially shiftable from an first position, wherein the mandrel maintains the locking segments outwardly within a cooperating groove formed in the packer assembly, to a second position, wherein the locking segments are permitted to move out of engagement with the well packer. A collet sleeve is secured to the mandrel by a shear pin and maintains the mandrel in the upper position. When it is desired to release the plug from the packer assembly, an actuating sleeve is attached to the lower end of a tubing string and run down the well casing to be engaged by the collet sleeve. A predetermined amount of upward force is applied to the collet sleeve by the actuating sleeve to shear the shear pin and release the mandrel from the upper position. By monitoring the upward force required to release the mandrel from its upper position, an operator is provided with a positive indication that the tubing guide has located the plug. Thereafter, a downward force applied to the mandrel will shift the mandrel to the lower position to retract the locking segments and expend the plug from the packer assembly.