Patent Application
20150122508
This disclosure relates generally to methods and apparatus for centralizing an expandable tubular member within a wellbore. More specifically, this disclosure relates to methods and apparatus for centralizing an expandable tubular member within a wellbore with a centralizer that includes collars with a frangible region.
Centralizers are used to maintain a radial stand-off between a wellbore tubular, such as a casing, and the interior wall of the wellbore in which the tubular is being installed. Maintaining this radial stand-off can help to reduce the likelihood of the wellbore tubular becoming stuck during running and provides a suitable annulus for cementing the tubular into the wellbore.
One type of centralizer is a bow spring centralizer that utilizes a plurality of flexible bow springs distributed around the circumference of the wellbore tubular. Bow spring centralizers generally include a pair of axially-spaced collars that surround the wellbore tubular and are coupled together by the plurality of bow springs. The bow springs are arranged to bow radially outwardly from the axis of the wellbore tubular so as to engage the wall of the wellbore. Thus, the bow springs provide stand-off from the wall of the wellbore and can flex, or collapse, inwardly in order to accommodate restrictions in the wellbore.
Expandable tubular are used in certain applications where wellbore restrictions may limit the diameter of a tubular that can be used. Expandable tubulars are run into the wellbore and then radially expanded to a larger diameter by any number of processes. Conventional centralizers are likely to interfere with, or be damaged during, the expansion process and often are not used with expandable tubular systems.
Thus, there is a continuing need in the art for methods and apparatus for centralizing expandable tubulars.
A centralizer comprises a plurality of bow springs, wherein each bow spring has a first and second end. A first collar is coupled to the first end of each of the plurality of bow springs and includes a longitudinal frangible region. A second collar is coupled to the second end of each of the plurality of bow springs and also includes a longitudinal frangible region.
For a more detailed description of the embodiments of the present disclosure, reference will now be made to the accompanying drawings, wherein:
It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.
Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Additionally, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. Furthermore, as it is used in the claims or specification, the term “or” is intended to encompass both exclusive and inclusive cases, i.e., “A or B” is intended to be synonymous with “at least one of A and B,” unless otherwise expressly specified herein.
Referring initially to
The centralizer 10 is coupled to an outer surface of an expandable tubular member 24 before the tubular member is run into a wellbore. The centralizer 10 may be coupled to the expandable tubular member 24 directly or may be axially constrained on the expandable tubular member 24 by one or more stop collars (not shown) that are coupled to the expandable tubular member 24 on at least one side of the centralizer 10. The stop collars may be coupled to the expandable tubular member 24 by set screws, brazing, or by other means. Each stop collar may also include a frangible region similar to the frangible regions 22 on the centralizer 10.
Once positioned in a wellbore, the expandable tubular member 24 is radially expanded. An expansion mandrel 26 may be disposed within the expandable tubular member 24 so that longitudinal translation of the expansion mandrel 26 through the expandable tubular member 24 radially expands the expandable tubular member 24. In other embodiments, the expandable tubular member 24 may be radially expanded by other methods.
Referring now to
The separated region 28 allows the first collar 14 and the second collar 16 to radially expand with the expandable tubular member 24. The longitudinal frangible regions 22 is designed to reduce the excess expansion forces needed to pass the expansion mandrel 26 through the portion of the expandable tubular member 24 fitted with the centralizer 10 and to ensure that the first collar 14 and the second collar 16 break at a predictable location. In certain embodiments, the expansion force needed to expand the expandable tubular member 24 and the centralizer 10 may be limited to a 10-15% increase over the expansion force needed to expand just the expandable tubular member 24. Without the longitudinal frangible region 22, the first collar 14 and second collar 16 may tend to break at or near the connection of a bow spring 12, which may cause a bow spring 12 to become misaligned and therefore degrade the performance of the centralizer 10.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and description. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present disclosure.
This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/899,997 filed Nov. 5, 2013, the disclosure of said applications is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61899997 | Nov 2013 | US |
