Borehole seal, backup and method

1. An assembly for reducing a radial gap between radially proximate components comprising:

a setting member having a first dimension that partially defines the radial gap, the setting member including a circumferential groove extending radially from the first dimension;

and a first toroid having a second dimension, the setting member operatively arranged to engage with the first toroid, wherein increasingly engaging the setting member with the first toroid enables a boundary dimension of the assembly to be extended toward the radial gap for reducing the radial gap, the circumferential groove operatively arranged to catch the first toroid when the setting member is fully engaged with the first toroid, wherein the setting member includes a first portion engaged with a second portion, the first portion arranged radially inwardly from the second portion, the first and second portions at least partially movable relative to each other.

2. The assembly of claim 1 , wherein the first and second portions include complementarily arranged ratchet teeth for enabling relative movement between the first and second portions in one direction only.

3. The assembly of claim 1 , wherein the first portion includes a first radially extending projection, the second portion includes a second radially extending projection, and relative movement between the first portion and the second portion is limited when the first radially extending projection contacts the second radially extending projection.

4. A system including a pair of assemblies comprising:

a setting member having a first dimension that partially defines the radial gap, the setting member including a circumferential groove extending radially from the first dimension; and a first toroid having a second dimension, the setting member operatively arranged to engage with the first toroid, wherein increasingly engaging the setting member with the first toroid enables a boundary dimension of the assembly to be extended toward the radial gap for reducing the radial gap, the circumferential groove operatively arranged to catch the first toroid when the setting member is fully engaged with the first toroid, wherein a first end assembly of the pair of assemblies is arranged facing a second end assembly of the pair of assemblies, the first toroids and a plurality of subsequent toroids arranged in a sealing area between the first and second end assemblies and wherein the setting member of each of the first and second end assemblies comprises a pair of first and second portions, the first portion of each pair arranged radially inwardly from the second portion of each pair, each pair of first and second portions at least partially movable relative to each other.

5. The system of claim 4 , wherein the sealing area isolates a first zone from a second zone of a borehole or a tubular.

6. The system of claim 4 , wherein the first end assembly includes a dog for initially preventing relative movement between the first and second portions of the first end assembly, wherein moving the first portion of the first end assembly enables the dog to enter a receiving area for providing relative movement between the first and second portions of the first end assembly.

7. The system of claim 4 , wherein the first portion of the second end assembly is anchored to a mandrel for restricting movement of the first portion of the second end assembly, the second portion of the second end assembly operatively connected to the first portion of the first end assembly for enabling movement of the second portion of the second end assembly based on movement of the first portion of the first end assembly.