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This disclosure relates generally to methods and apparatus for expanding a tubular member in a wellbore. More specifically, this disclosure relates to methods and apparatus for expanding a tubular member into an oversized base casing.
Expandable casings, liners, and other tubulars are utilized in the construction of wells to line the wellbore. Expandable tubulars are disposed in a well in an unexpanded state and then can be radially expanded to increase the diameter of the tubular. The expansion typically takes place via the application of mechanical expansion tools, hydraulic pressure, or a combination thereof to plastically deform the tubular. Expandable tubulars can therefore provide an increased tubular diameter as compared to the use of conventional tubulars.
Expandable tubulars are often secured in a wellbore by compressing an elastomer between a portion of the expanded tubular and the existing base casing. In certain applications, the existing base casing may have an inner diameter that makes the compression of the elastomer difficult due to the size of the inner diameter of the base casing and the expanded diameter of the expandable tubular. If the inner diameter of the base casing is too large, the expansion of the expandable tubular may not provide sufficient compression of the elastomer or require the use of an increased thickness of elastomer. In the most extreme of these applications, the size of the base casing may prevent the use of conventional expandable tubulars or may require special preparation of the wellbore to accommodate a larger expandable tubular.
Thus, there is a continuing need in the art for methods and apparatus for expanding a tubular member into an oversized base casing that overcome these and other limitations of the prior art.
An expandable tubular member comprises a first portion having a first inner diameter and a first wall thickness. A second portion of the expandable tubular member has an increased inner diameter and an increased wall thickness. A transition portion of the expandable tubular member is defined by a wall thickness that varies non-linearly between the first wall thickness and the increased wall thickness.
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
In certain applications, the expanded diameter 22 of the tubular member 10 plus the thickness 26 of the tubular may not provide for sufficient compression of the anchor members 24 in the annulus between the tubular and the base casing 16. In certain embodiments, the thickness of the anchor members 24 may be increased so that sufficient compression can be achieved. In other embodiments, the thickness 26 of a portion of the expandable tubular member 10 can be increased, as shown in
As can be seen in
In order to reduce the expansion forces required in the portion of an expandable tubular member 10 having an increased wall thickness 26, the wall thickness can be decreased by increasing the inner diameter through the thickened section. Increasing the unexpanded inner diameter reduces the amount of radial expansion that is seen by the increased thickness section. Because the amount radial expansion is decreased, the expansion force is also decreased.
Referring now to
Referring now to
Referring now to
The inner taper 42 for the linearly increasing wall thickness embodiment of
Referring back to
Each of the expansion force curves 54, 56, 58 is substantially equal during the expansion of the portions of the tubular where the inner diameter and thickness are constant. The expansion force curves 54, 56, 58 diverge as the diameter and/or thickness of the tubular transitions from the nominal thickness portions to the increased thickness portions. Expansion force curve 54 shows an increase in expansion force during the transition portion between the nominal thickness portions and the increased thickness portion of the tubular. This increased expansion force is due to the increasing wall thickness of the tubular and the changing expansion percentage of the tubular. Because the wall thickness is increasing linearly and the expansion percentage is decreasing non-linearly, the expansion force is changing in a non-linear fashion. It is also observed that the transitions from the nominal thickness sections to the increased thickness section require more expansion force than expanding through either of the constant diameter/constant thickness sections.
The expansion force curve 56 shows that by increasing the wall thickness in a non-linear manner (as shown in
The expansion force needed to expand the expandable tubular shown in
Thus, using any of the embodiments illustrated in
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.