EXPANDABLE RETAINING SHOE

An improved downhole tool apparatus and method for limiting the extrusion of a packer element. The apparatus includes a mandrel having a packer element assembly. Packer retaining shoes are disposed about the mandrel at the ends of the packer element assembly. The packer retaining shoes have an inner retainer and an outer retainer. The inner retainer has a plurality of segments having gaps therebetween that expand in width when the retaining shoe is moved from the initial position in which it is disposed about the mandrel to an expanded position wherein it engages the casing to limit the extrusion of the packer element assembly. The outer shoe is likewise made up of a plurality of segments having gaps therebetween that will expand. The inner shoe segments cover the gaps that exist between the outer shoe segments and the outer shoe segments cover the gaps that exis t between the inner shoe segments so that extrusion is limited. The retaining shoes provid e enhanced high temperature and higher pressure performance in that extrusion in wells havin g high temperature and high pressure is severely limited if not completely prevente d.