Radially expandable anti-extrusion backup ring

An apparatus, comprising:

• a wedge ramp defining an external tapered surface;
• and
• a backup ring positioned around the wedge ramp,
• wherein the backup ring comprises:
• an inner ring segment defining opposing first and second end portions, and
• an outer ring segment defining opposing third and fourth end portions,
• wherein the third end portion of the outer ring segment telescopically receives, and overlaps, the first end portion of the inner ring segment,
• and
• wherein the backup ring is slidable up the external tapered surface of the wedge ramp to:
• radially expand the backup ring, and
• prevent, or at least reduce, extrusion of a sealing element. The apparatus of claim 6, further comprising:
• a piston positioned adjacent the wedge ramp and movable to slide the backup ring up the external tapered surface of the wedge ramp.

A backup ring, comprising:

• an inner ring segment defining opposing first and second end portions;
• and
• an outer ring segment defining opposing third and fourth end portion,
• wherein the third end portion of the outer ring segment telescopically receives, and overlaps, the first end portion of the inner ring segment,
• and
• wherein the backup ring is slidable up an external tapered surface of a wedge ramp to:
• radially expand the backup ring, and
• prevent, or at least reduce, extrusion of a sealing element.