Patent attributes
Opposed cones for slips on a packer have an annular undercut in general alignment with the end of the cone that has the slip ramp. The undercut faces the mandrel on which the cones can be driven together to radially extend the slips. A high modulus insert sleeve is interference fitted to the undercut. This results in the cone exterior surface being in hoop stress tension before the slips are set. Once the slips are set and a reaction load comes radially back from the surrounding tubular into which the slips have extended there is a tendency for the reaction force to put the exterior surface of the cones into compressive hoop stress. The initial tensile hoop stress from the sleeve placement acts to at least in part offset the reaction force tending to create compressive hoop stress. The net loading and deflection of the mandrel is minimized.
