Production risers having rigid inserts and systems and methods for using

Patent metadata

Field	Value
Publication number	US-9850719-B1
Application number	US-201715495012-A
Country	US
Kind code	B1
Filing date	Apr 24, 2017
Priority date	Apr 24, 2017
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

An apparatus enables modifying a riser's operating parameters for transporting production fluids from a subsea well to an offshore production facility after an initial period of production to address changes over time in the conditions of the reservoir and/or the riser without removing the original riser. An insert riser having a smaller diameter is inserted into the riser after the initial period. The original riser has a recessed seal face for receiving seal element(s) and a recessed lock groove for receiving a locking ring. An intervention coiled tubing having a sleeve removal tool is inserted into the riser to engage a protective sleeve covering the recessed seal face. The tubing is pulled to the floating structure thereby removing the protective sleeve and the temporary retaining ring from the production riser, exposing the recessed seal face. The insert riser can then be inserted into the riser and locked into place.

First claim

What is claimed is:

1. An apparatus for facilitating a change in diameter of a riser for transporting production fluids from a subsea well to a production facility on a floating structure after an initial period of production, comprising:
a. a production riser having a topsides end for attaching to a riser hanger assembly on the floating structure, a subsea end for supporting on a pipeline end termination structure located on a seabed and attaching to a subsea pipeline, an outer production riser surface and an inner production riser surface, wherein the inner production riser surface comprises a polished recessed seal face proximate the subsea end for receiving one or more seal elements and a recessed lock groove proximate the polished recessed seal face;
b. a protective sleeve proximate the subsea end for covering the polished recessed seal face, wherein the protective sleeve has an outer sleeve surface for partially engaging the inner production riser surface and an inner sleeve surface comprising a groove therein for receiving a sleeve removal tool;
c. a temporary retaining ring in the recessed lock groove in the inner production riser surface for holding the protective sleeve in place during the initial period of production; and
d. an insert riser having an insert riser length, an outer insert riser surface and an inner insert riser surface, for insertion into the production riser following the initial period of production, wherein the insert riser comprises one or more seal elements around the outer insert riser surface for engaging the polished recessed face of the production riser and a locking ring around the outer insert riser surface for fitting into the recessed lock groove of the production riser.

2. The apparatus of claim 1 further comprising a temporary seal between the polished recessed face and the protective sleeve for protecting the polished recessed seal face during the initial period of production.

3. The apparatus of claim 1 further comprising a plurality of centralizers along the insert riser length for centering the insert riser within the production riser.

4. The apparatus of claim 3 wherein, when the insert riser is inserted into the production riser, an annulus between the outer insert riser surface and the inner production riser surface is formed.

5. The apparatus of claim 4 further comprising a seal assembly between the topsides end of the production riser and the riser hanger assembly for isolating the annulus at the topsides end of the production riser.

6. The apparatus of claim 4 further comprising a spool piece having an opening therein located between the topsides end of the production riser and the riser hanger assembly wherein the opening provides an access point for the injection of liquids or gas into the annulus.

7. The apparatus of claim 6 wherein the spool piece further comprises an injection check valve for injecting the liquids or gas into the annulus between the outer insert riser surface and the inner production riser surface.

8. The apparatus of claim 7 further comprising at least one tubing extending into the annulus having a topside end connected to the opening and a subsea end open to the annulus for introducing liquids into the annulus at a subsea location.

9. The apparatus of claim 4 wherein the insert riser further comprises a side pocket mandrel comprising gas lift valves for injecting gas into the insert riser.

10. A production riser system for facilitating a change in diameter of a riser for transporting production fluids from a subsea well to a production facility on a floating structure after an initial period of production, the system comprising:
a. a pipeline end termination structure located on a seabed a distance along the seabed from the floating structure; and
b. the apparatus of claim 1 wherein the subsea end of the production riser is mounted on the pipeline end termination structure and the topsides end of the production riser is attached to the riser hanger assembly on the floating structure.

11. The production riser system of claim 10 further comprising a temporary seal between the polished recessed face and the protective sleeve of the apparatus of claim 1 for protecting the polished recessed seal face during the initial period of production.

12. The production riser system of claim 10 further comprising a plurality of centralizers along the insert riser length for centering the insert riser within the production riser of the apparatus of claim 1 .

13. The production riser system of claim 10 wherein when the insert riser is inserted into the production riser, an annulus is formed between the outer insert riser surface and the inner production riser surface of the apparatus of claim 1 .

14. The production riser system of claim 13 further comprising a seal assembly between the topsides end of the production riser and the riser hanger assembly for isolating the annulus at the topsides end of the production riser.

15. A method for changing diameter of a riser for transporting production fluids from a subsea well to a production facility on a floating structure after an initial period of production, the method comprising:
a. providing the production riser system of claim 10 ;
b. at a desired time after the initial period of production, inserting intervention coiled tubing into the production riser of the apparatus of claim 1 from the floating structure wherein the tubing comprises a sleeve removal tool at a distal end thereof;
c. engaging the groove of the inner sleeve surface of the protective sleeve with the sleeve removal tool; and
d. pulling the intervention coiled tubing to the floating structure thereby removing the protective sleeve and the temporary retaining ring from the production riser and exposing the polished recessed seal face.

16. The method of claim 15 further comprising inserting from the floating structure the insert riser wherein the insert riser has a distal end, an insert riser length, an outer insert riser surface and an inner insert riser surface into the production riser, and fully inserting the insert riser such that the seal elements engage the polished recessed seal face and the locking ring fits into the recessed lock groove.

17. The method of claim 15 further comprising partially inserting from the floating structure the insert riser wherein the insert riser has a distal end, an insert riser length, an outer insert riser surface and an inner insert riser surface into the production riser, such that the seal elements do not engage the polished recessed seal face and the retaining ring does not fit into the recessed lock groove and a flow path is provided from the inner insert riser surface into the production riser around the distal end of the insert riser; and
injecting a fluid into the insert riser from the floating structure and allowing the fluid to flow along the flow path, thereby flushing an annulus between the outer insert riser surface and the inner production riser surface.

Assignees

• Chevron Usa Inc

Inventors

• Ferrier Brian
• Mazaheri Alireza

Classifications

• E21B17/01 Primary

  Risers · CPC title

• E21B17/12

  Devices for placing or drawing out wear protectors · CPC title

• E21B17/1007

  for the internal surface of a pipe, e.g. wear bushings for underwater well-heads · CPC title

• E21B19/004

  supporting a riser from a drilling or production platform · CPC title