Wiper plug

1. A wiper plug comprising:

a mandrel having a nose portion at a leading end thereof;

a seal unit disposed about the mandrel, the seal unit including a body and one or more fins extending outwardly from the body; and

an anti-extrusion assembly disposed about the mandrel at a leading end of the seal unit, the anti-extrusion assembly arranged to transition between a first configuration, in which the anti-extrusion assembly is not energized, and a second configuration, in which the anti-extrusion assembly is energized;

wherein the nose portion protrudes beyond the anti-extrusion assembly, and the anti-extrusion assembly further comprises:

a setting ring disposed adjacent the seal unit;

a retaining ring; and

a ductile ring disposed between the setting ring and the retaining ring.

2. The wiper plug of claim 1 , wherein when the anti-extrusion assembly transitions to the second configuration, the setting ring moves axially on the mandrel towards the retaining ring, thereby deforming the ductile ring from a radially retracted condition to a radially extended condition.

3. The wiper plug of claim 2 , wherein the setting ring includes:

a base disposed between the ductile ring and the mandrel; and

a projection extending radially from the base, the projection disposed between the seal unit and the ductile ring.

4. The wiper plug of claim 3 , wherein the base includes an extension between a portion of the retaining ring and the mandrel.

5. The wiper plug of claim 4 , wherein movement of the setting ring is limited by the extension contacting a shoulder.

6. The wiper plug of claim 3 , wherein the projection has a first surface facing the ductile ring, the first surface tapering from a location proximal to the retaining ring at the base to a location distal from the retaining ring at an outer edge of the projection.

7. The wiper plug of claim 6 , wherein the retaining ring has a second surface facing the ductile ring and having:

a radially inner location axially proximal to the projection of the setting ring; and

a radially outer location axially distal from the projection of the setting ring.

8. The wiper plug of claim 1 , wherein:

an outer surface of the mandrel includes a slope;

a first outer diameter of the mandrel at a first end of the slope proximal to the leading end of the mandrel is greater than a second outer diameter of the mandrel at a second end of the slope distal from the leading end of the mandrel; and

the seal unit includes an inner surface having a first internal taper disposed adjacent the slope.

9. The wiper plug of claim 8 , wherein the inner surface of the seal unit includes a second internal taper disposed between the first internal taper and an internal shoulder extending substantially perpendicular to a longitudinal axis of the mandrel.

10. A wiper plug comprising:

a mandrel;

a seal unit disposed about the mandrel, the seal unit including a body and one or more fins extending outwardly from the body; and

an anti-extrusion assembly disposed about the mandrel at a leading end of the seal unit, the anti-extrusion assembly arranged to transition between a first configuration, in which the anti-extrusion assembly is not energized, and a second configuration, in which the anti-extrusion assembly is energized, in response to a pressure applied to an obturating object landed in the wiper plug.

11. The wiper plug of claim 10 , wherein the anti-extrusion assembly further comprises:

a setting ring disposed adjacent the seal unit;

a retaining ring; and

a ductile ring disposed between the setting ring and the retaining ring.

12. The wiper plug of claim 11 , wherein when the anti-extrusion assembly transitions to the second configuration, the setting ring moves axially on the mandrel towards the retaining ring, thereby deforming the ductile ring from a radially retracted condition to a radially extended condition.

13. The wiper plug of claim 12 , wherein the setting ring includes:

a base disposed between the ductile ring and the mandrel; and

a projection extending radially from the base, the projection disposed between the seal unit and the ductile ring.

14. The wiper plug of claim 13 , wherein the base extends between a portion of the retaining ring and the mandrel.

15. The wiper plug of claim 14 , wherein movement of the setting ring is limited by the extension contacting a shoulder.

16. A method comprising:

suspending a wiper plug from a support disposed in a tubular; and

energizing an anti-extrusion assembly of the wiper plug while the wiper plug remains suspended from the support, the energizing comprising:

landing an obturating object in the wiper plug; and

applying a pressure to the landed obturating object.

17. The method of claim 16 , wherein energizing the anti-extrusion assembly further comprises:

communicating the applied pressure to a seal unit of the wiper plug, thereby causing the seal unit to apply a force to the anti-extrusion assembly.

18. The method of claim 17 , wherein the force causes a setting ring of the anti-extrusion assembly to move relative to a retaining ring, thereby deforming a ductile ring disposed between the setting ring and the retaining ring from a radially retracted condition to a radially extended condition.

19. The method of claim 16 , further comprising releasing the wiper plug from the support after energizing the anti-extrusion device.