Back-up ring system for elastomeric sealing elements
A back-up ring system incudes an outer C-ring, an inner C-ring that mates with the outer C-ring, the inner C-ring including a first rupture port, and a ring sheath that fits onto the inner C-ring, the ring sheath including a cut-out region, and a second rupture point. The inner C-ring further includes a blocking segment that angularly offsets the first and second rupture points. The cut-out region of the ring sheath mates with the blocking segment of the inner C-ring. The ring sheath further incudes a ‘7’ shaped cross-sectional profile.
1. A back-up ring system, comprising:
an outer C-ring;
an inner C-ring that mates with the outer C-ring, the inner C-ring comprising a first rupture point; and
a ring sheath that fits onto the inner C-ring, the ring sheath comprising:
a cut-out region; and
a second rupture point,
wherein the inner C-ring further comprises a blocking segment that angularly offsets the first and second rupture points,
wherein the cut-out region of the ring sheath mates with the blocking segment of the inner C-ring,
wherein the ring sheath further comprises a ‘7’ shaped cross-sectional profile, and
wherein a lower branch of the ‘7’ shaped cross-sectional profile is tapered.
2. The back-up ring system of claim 1 ,
wherein the blocking segment spans a 45° section of the inner C-ring, and
wherein the cut-out region spans a 47° section of the ring sheath.
3. The back-up ring system of claim 1 , further comprising at least one alignment pin that connects the ring sheath to the inner C-ring.
4. The back-up ring system of claim 1 , wherein the outer C-ring and the inner C-ring form a ‘V’ shaped profile.
5. A tool, comprising:
a mandrel;
an elastomer element;
a support ring;
the back-up ring system of claim 1 , wherein the support ring is disposed between the elastomer element and the back-up ring system on the mandrel; and
a gauge ring disposed on the mandrel that supports the back-up ring system.
6. The tool of claim 5 , wherein the gauge ring supports the outer C-ring of the back-up ring system.
7. The tool of claim 5 , wherein the gauge ring comprises a singled chamfered corner.
8. The tool of claim 5 , wherein, in a set position:
the back-up ring system is cupped evenly between the support ring and the gauge ring;
a mating face of the support ring abuts the gauge ring with face-to-face contact; and
the elastomer element and the back-up ring system bridge a gap between the mandrel and a surrounding wellbore or casing.
9. The tool of claim 8 , wherein, in the set position, an outer apex of the support ring is angled and lies perpendicular to the ring sheath.
10. The tool of claim 8 ,
wherein the outer C-ring and the inner C-ring of the back-up ring system form a ‘V’ shaped profile, and
wherein the support ring comprises a parallel contact region that evenly contacts the ‘V’ shaped profile to stabilize the set position.
11. The tool of claim 5 ,
wherein the outer C-ring and the inner C-ring of the back-up ring system form a ‘V’ shaped profile, and
wherein the support ring comprises a top face that is perpendicular to the ‘V’ shaped profile.
12. The tool of claim 5 , wherein the support ring comprises an inner face that is tapered to match an end of the elastomer element.
13. The tool of claim 5 , further comprising:
a PEEK ring installed in the support ring; and
a foldback ring that abuts the PEEK ring,
wherein the foldback ring does not contact a surrounding wellbore or casing.
14. A method, comprising:
running the tool of claim 5 inside a wellbore; and
axially deploying and compressing the elastomer element into a set position,
wherein, in the set position, the elastomer element fills a space between the mandrel and the surrounding wellbore, creating a seal.
15. A method comprising:
running the tool of claim 13 inside a wellbore; and
axially deploying and compressing the elastomer element into a set position,
wherein, in the set position, the elastomer element fills a space between the mandrel and the surrounding wellbore, creating a seal.
16. A back-up ring system, comprising:
an outer C-ring;
an inner C-ring that mates with the outer C-ring, the inner C-ring comprising a first rupture point; and
a ring sheath that fits onto the inner C-ring, the ring sheath comprising:
a cut-out region; and
a second rupture point,
wherein the inner C-ring further comprises a blocking segment that angularly offsets the first and second rupture points,
wherein the cut-out region of the ring sheath mates with the blocking segment of the inner C-ring,
wherein the ring sheath further comprises a ‘7’ shaped cross-sectional profile,
wherein the blocking segment spans a 45° section of the inner C-ring, and
wherein the cut-out region spans a 47° section of the ring sheath.