US 5,311,938 A · Retrievable packer for high temperature, high pressure service

Abstract

In a retrievable packer adapted for service under high temperature and high pressure operating conditions, improved sealing is provided by a seal element prop surface which is radially offset with respect to the seal element support surface of the packer body mandrel. At least one seal element is supported on the elevated prop surface and is subjected to a radial squeeze in the set configuration, even though the lowermost outside seal element may be subject to longitudinal separation. The split level seal element support arrangement provides an annular pocket into which the seal elements can be retracted upon release and retrieval of the packer, thereby providing clearance for unobstructed retrieval. Upon release of the packer, a retainer collar is shifted away from a metal backup shoe, thereby providing an annular pocket into which the metal backup shoe is deflected, so that it does not obstruct the drift clearance as the packer is retrieved. The upper outside seal element is reinforced by a garter spring assembly having deformation resistant reinforcing material enclosed within a helical wound coil. Preloading of the seal element assembly is provided by a cover sleeve which releases when a predetermined amount of compression has been achieved. The controlled preloading of the seal elements assists movement of the elements from the lower O.D. of the packer mandrel to the upper O.D. of the prop surface, and the seal elements are forced to expand into the annulus uniformly for preventing the formation of uneven extrusion gaps.

Claims21

Dependent claims

In a well packer having a tubular body mandrel, an anchor slip assembly, a seal element assembly including an expandable seal element movably mounted for longitudinal travel along a seal element support surface of said body mandrel, and force transmitting apparatus coupled to said anchor slip assembly and said seal element assembly for radially extending said anchor slip element assembly and radially expanding said seal element assembly into set engagement against the internal sidewall bore of a well casing, the improvement comprising:

prop apparatus disposed on said body mandrel and having a tubular seal element prop member radially engagable by said seal element assembly, the seal element prop member having a prop surface which is radially offset with respect to the seal element support surface of said body mandrel;
and,
the unexpanded radial thickness of the expandable seal element being greater than the radial spacing between the seal element prop surface and the internal sidewall bore of the well casing, but less than the radial spacing between the seal element support surface and the internal sidewall bore of the well casing.

In a well packer having a tubular body mandrel, an anchor slip assembly, a seal element assembly movably mounted for longitudinal travel along a seal element support surface of said body mandrel, and force transmitting apparatus coupled to said anchor slip assembly and said seal element assembly for radially extending said anchor slip element assembly and radially expanding said seal element assembly into set engagement against the internal bore sidewall of a well casing, the improvement comprising:

prop apparatus disposed on said body mandrel and engagable by said seal element assembly, said prop apparatus having a seal element prop surface which is radially offset with respect to the seal element support surface of said body mandrel;
said seal element assembly including first and second longitudinally compressible, radially expandable outside seal elements, and a third seal element disposed intermediate the first and second outside seal elements, and wherein the longitudinal dimensions of said sealing elements and said prop surface are so selected that at least the first outside seal element is radially compressed against said seal element prop surface and the second outside seal element is radially compressed against said seal element support surface when said seal element assembly is expanded into sealing engagement against a well casing;
an annular backup shoe mounted on said body mandrel adjacent said seal element assembly, said backup shoe defining a radial bridge between said body mandrel and a well casing when said seal element assembly is expanded into engagement against the internal bore sidewall of the well casing;
and,
a seal element retainer sleeve slidably mounted for longitudinal movement along said body mandrel;
a seal element retainer collar movably mounted on said retainer sleeve for longitudinal movement from a retracted position in which said seal element retainer collar and retainer sleeve are engagable against said backup shoe to an extended position longitudinally spaced from said backup shoe, thereby defining a pocket for receiving said backup shoe as it undergoes deflection during retrieval of said packer.

3 more elements

prop apparatus disposed on said body mandrel and engagable by said seal element assembly, said prop apparatus having a seal element prop surface which is radially offset with respect to the seal element support surface of said body mandrel;
said seal element assembly including first and second longitudinally compressible, radially expandable outside seal elements, and a third seal element disposed intermediate the first and second outside seal elements, and wherein the longitudinal dimensions of said sealing elements and said prop surface are so selected that at least the first outside seal element radially is compressed against said seal element prop surface and the second outside seal element is radially compressed against said seal element support surface when said seal element assembly is expanded into sealing engagement against a well casing;
a cover sleeve mounted on said body mandrel for longitudinal movement from an extended position in which said prop surface is covered by said sleeve, to a retracted position in which the seal element prop surface is uncovered;
at least one shear pin releasably securing said cover sleeve to said body mandrel at said extended position;
stop means disposed on said body mandrel adjacent said prop surface, said cover sleeve being engagable against said stop means at the limit of its travel to the retracted position;
said cover sleeve having a tubular sidewall and an annular head radially offset from said sidewall, said annular head being disposed in slidable engagement with said seal element prop surface, and said cover sleeve head being engagable against said stop means when said sleeve is moved to the retracted position;
said body mandrel having an annular shoulder defining said stop means, said annular shoulder projecting radially with respect to said prop surface;
and,
the tubular sidewall of said cover sleeve being intersected by a longitudinal slot, and including a radially projecting guide lug mounted on said body mandrel, said guide lug being received within said slot.

6 more elements

Dependencies are inferred from the claim text.

Retrievable packer for high temperature, high pressure service

Life of this patent

Retrievable packer for high temperature, high pressure service

Life of this patent

Abstract

Claims21