Patent ID: 7909109

Claim:
An apparatus for use in a casing string, comprising: a tubular profile sub for attachment into and forming a part of the casing string, the profile sub having an inner diameter with an annular recess formed therein, the annular recess having a length and having a diameter greater than an inner diameter of the casing string; a cement retainer comprising: an anchor carriage including a section formed as a helically cut spring coil by a helical cut extending completely through a sidewall of the anchor carriage from a radially interior edge of the sidewall to a radially exterior edge of the sidewall, the anchor carriage having a length selected to be less than the annular recess length and being sized to pass through the casing string when radially compressed and to have an outer diameter when radially expanded greater than the casing string inner diameter, a mandrel having an outer surface, an upper end and a lower end, the mandrel sized to move through the casing string in which it is to be used, the mandrel carrying the anchor carriage and being selected to limit axial movement of the anchor carriage relative to the mandrel and to permit the anchor carriage to be compressed against the mandrel to fit inside the inner diameter of the casing string and to remain interengaged when the anchor carriage is expanded and latched into the annular recess of the casing string; and a seal assembly on the mandrel for sealing against the casing string inner diameter, enabling the cement retainer to be pumped down the casing string into the profile sub, and for preventing an upward flow of cement between the mandrel and the profile sub.