Subsea isolation sleeve system

Patent metadata

Field	Value
Publication number	US-10633966-B2
Application number	US-201715833013-A
Country	US
Kind code	B2
Filing date	Dec 6, 2017
Priority date	Dec 6, 2017
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

A technique facilitates pressure testing of a seal positioned between a wellhead and a subsea tree system. The technique utilizes an isolation sleeve which may comprise a mandrel having an internal mandrel passage as well as a lower seal and an upper seal positioned along an exterior of the mandrel. The isolation sleeve also may comprise a retention member mounted along the exterior of the mandrel. The retention member, e.g. a retention nut, may be rotatably mounted about the exterior of the mandrel and may comprise external threads or other mechanism for securing the isolation sleeve to the subsea tree system. In some embodiments, the upper end of the isolation sleeve may be constructed in a uniform manner for insertion into a universal profile of the subsea tree system.

First claim

What is claimed is:

1. A system for use in a subsea operation, comprising:
a wellhead having an internal wellhead passage;
a subsea tree system having an internal passage, the subsea tree system being sealably coupled with the wellhead via a seal; and
an isolation sleeve extending from the internal passage of the subsea tree system into the internal wellhead passage to facilitate pressure testing of the seal, the isolation sleeve comprising:
a mandrel formed as a single, continuous structure having an internal mandrel passage;
a lower seal position along an exterior of the mandrel for sealing engagement with the wellhead;
an upper seal positioned along the exterior of the mandrel for sealing engagement with the subsea tree system;
a retention nut mounted along the exterior of the mandrel by moving the retention nut a sufficient distance along the exterior of the mandrel to enable subsequent positioning of the upper seal above the retention nut along the exterior of the mandrel, the retention nut being threadably engaged with the subsea tree system along the internal passage; and
an upper seal retainer mounted to the mandrel above the upper seal to secure the upper seal along the mandrel, the upper seal retainer being sized to accommodate insertion into the internal passage of the subsea tree system.

2. The system as recited in claim 1 , wherein the subsea tree system comprises a Christmas tree, the retention nut being threadably engaged with the Christmas tree.

3. The system as recited in claim 1 , wherein the subsea tree system comprises a tubing head spool, the retention nut being threadably engaged with the tubing head spool.

4. The system as recited in claim 1 , wherein the lower seal has a larger diameter than the upper seal.

5. The system as recited in claim 1 , wherein the upper seal has a larger diameter than the lower seal.

6. The system as recited in claim 1 , wherein the retention nut is slid onto the mandrel along the exterior of the mandrel and contained by at least one of an upper mandrel abutment and a lower mandrel abutment.

7. The system as recited in claim 6 , wherein the upper mandrel abutment comprises a split ring.

8. The system as recited in claim 1 , wherein the lower seal and the upper seal are secured in place along the mandrel via a lower seal retainer and an upper seal retainer, respectively.

9. A system, comprising:
an isolation sleeve for subsea pressure testing, the isolation sleeve comprising:
a mandrel having an internal mandrel passage;
a lower seal positioned along an exterior of the mandrel;
an upper seal;
a retention member positioned along the exterior of the mandrel by sliding the retention member a sufficient distance along the exterior of the mandrel to enable subsequent positioning of the upper seal above the retention member along the exterior of the mandrel, the retention member being constructed for secure engagement with a subsea tree system; and
an upper seal retainer mounted to the mandrel above the upper seal to secure the upper seal along the mandrel.

10. The system as recited in claim 9 , wherein the retention member is rotatably positioned adjacent an abutment along the mandrel, the retention member having external threads oriented for threaded engagement with a subsea tree system.

11. The system as recited in claim 10 , wherein the retention member comprises a retention mechanism to resist unthreading of the retention member after being threadably engaged with the subsea tree system.

12. The system as recited in claim 9 , wherein the lower seal has a larger diameter than the upper seal.

13. The system as recited in claim 9 , wherein the upper seal has a larger diameter than the lower seal.

Assignees

• Onesubsea Ip Uk Ltd

Inventors

• Pollak Joshua
• Santilli Claudio

Classifications

• E21B17/042

  Threaded · CPC title

• E21B47/0001

  Fixed Constructions · mapped topic

• E21B33/035

  specially adapted for underwater installations (E21B33/043, E21B33/064, E21B33/076 take precedence) · CPC title

• E21B34/04

  in underwater well heads · CPC title

• E21B47/1025 Primary

  Fixed Constructions · mapped topic