Patent Application
20050023001
This application claims benefit of Great Britain patent application serial number GB 0315997.7, filed Jul. 9, 2003, which is herein incorporated by reference.
1. Field of the Invention
This invention relates to expanding tubing, and in particular to expansion of tubing downhole. Embodiments of the invention relate to anchoring and expanding tubing downhole.
2. Description of the Related Art
The present applicant and others have made various proposals relating to anchoring tubing in a bore by diametrically expanding the tubing into engagement with surrounding tubing. For example, in applicant's GB-A-2 345 308 there is disclosed a method of creating a tubing hanger by expanding tubing into engagement with existing tubing using a radially expandable tool, and subsequently advancing the tool through anchored tubing to expand the tubing.
It is among the objectives of embodiments of the invention to provide alternative methods for anchoring and expanding tubing.
According to the present invention there is provided a method of anchoring and expanding tubing, the method comprising:
According to another aspect of the invention there is provided apparatus for expanding tubing, the apparatus comprising:
The invention has particular utility in downhole applications, but may be utilised in other situations, for example in subsea risers or in subsea or surface pipelines. For downhole applications the tubing may take any appropriate form or serve any appropriate function, but will typically be bore-lining casing.
Initial expansion of a portion of the tubing using the expansion tool may serve to anchor the tubing relative to the bore wall, which will typically be defined by existing tubing, which existing tubing may be cemented and thus of fixed diameter and not capable of expansion. The use of an expansion tool having at least one radially movable expansion member avoids many of the risks inherent in attempting to expand tubing in such situations, as the expansion tool may accommodate anomalies in tubing shape, condition and internal diameter (ID) dimension. The cone expander may then be utilised to expand a further portion of the tubing, which may comprise all or a substantial portion of the remainder of the tubing below the anchor. The cone expander may be advanced through the tubing relatively quickly, and may be better suited to expanding extended lengths of tubing than other forms of expansion tools.
The expansion tool for expanding said portion of the tubing may take any appropriate form, including a cone which is one or both of compliant and expandable, such as an expansion tool having a substantially cone-shaped expansion member adapted to be advanced axially through the tubing and capable of radial deflection to accommodate, for example, sections of tubing which cannot be expanded to a desired diameter. The cone may be adapted for sliding contact with the tubing or may feature a surface at least partially defined by rolling elements. Most preferably however, the expansion tool is a rotary expander, and may feature a plurality of circumferentially spaced expansion members. Examples of rotary expanders are set out in applicant's WO00/37766, the disclosure of which is incorporated herein by reference.
The expansion tool may be actuated to extend the expansion member by any appropriate means, but is most preferably fluid-pressure actuated.
The tubing may be cemented prior to or following expansion.
Said portion of the tubing may be expanded to engage the bore wall while retaining a fluid passage between the tubing and the wall. The passage may be useful to allow displacement of fluid in subsequent cementing operations. Alternatively, ports or other means may be provided to permit fluid bypass.
These and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIGS. 1 to 5 are schematic illustrations of tubing being anchored in a bore and then expanded, in accordance with a preferred embodiment of the present invention.
The figures illustrate steps in the process of anchoring and then expanding a section of casing 10 in a drilled subsurface bore 12. In particular, the casing 10 is located with an upper end overlapping the lower end of existing casing 14, and the remainder of the casing 10 extending into an unlined section of bore below the existing casing 14.
The casing 10 is run into the bore 12 together with an anchoring and expansion apparatus 16, and mounted on the lower end of an appropriate pipe string 18. The apparatus comprises two expansion tools 20, 22, a compliant rotary expander 20 and a cone expander 22. Initially, the rotary expander 20 is located within the upper end of the casing 10, and is run into the bore in this position.
The expander 20 features a number of piston-mounted rollers 24 on the hollow tool body 28. The rollers 24 are initially retracted, but application of elevated fluid pressure to the interior of the body 28, via the pipe string 18, urges the rollers 24 radially outwardly, as will be described. The expander 20 is initially fixed axially relative to the casing 10 by retractable dogs 30.
The cone expander 22 is a fixed diameter cone of suitable hard-wearing material, and may include metallic or ceramic elements. The expander is mounted on the pipe string 18 above the rotary expander 20, and is initially located above the upper end of the casing 10.
The casing string 10 will be made up on surface and then run into the bore 12 with the anchoring and expansion apparatus 16 and located relative to the existing casing 14 as illustrated in
In any event, the dogs 30 may then be released (
The remainder of the casing 10, extending into the unlined section of bore below the casing 14, may then be expanded by driving the cone expander 22 axially down through the casing 10, as illustrated in
Those of skill in the art will appreciate that the invention provides a method of anchoring and expanding tubing which takes advantage of the attributes of the different forms of expansion tools.
Those skilled in the art will also recognise that this embodiment is merely exemplary of the present invention and that various modifications and improvements may be made thereto, without departing from the present invention. For example, rather than casing 10 as described above, the invention may be utilised to anchor and locate liner in a bore.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0315997.7 | Jul 2003 | GB | national |
