For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which:
Certain terms are used throughout the following description and claims to refer to particular components. This document does not intend to distinguish between components that differ in name but not function.
“Actuator” refers to a device comprising one or more annular pistons and a cylinder slidingly arranged over the pistons, having at least one pressure chamber per piston, and capable of providing a sufficient force to axially move the expansion swage inside the expandable tubular to plastically radially expand the tubular.
“Anchor” refers to a device capable of selective engagement with the inner surface of the tubular and preventing movement of selected parts of the tubular expansion apparatus relative to the tubular.
“Expandable tubular” or “tubular” refers to a member such as a liner, casing, borehole clad to seal a selected zone, or the like that is capable of being plastically radially expanded.
“Expansion swage” refers to a device capable of plastically increasing tubular diameter when it is displaced in the longitudinal direction of the tubular. For instance, an expansion swage includes a tapered cone of a fixed or variable diameter.
“Length of expansion stroke” refers to the maximum displacement of the expansion swage under a single action of the actuator.
“Stopper” refers to a device capable of transmitting a load from the anchor to selected parts of the tubular expansion apparatus.
Without being limited by theory, it has been established that during plastic deformation of metals, the volume of the material may not change and remains constant. Thus, during radial expansion, the stretching of the tubular in the hoop direction may be compensated by shrinkage in the longitudinal direction and by shrinkage in the radial direction (e.g., wall thickness). If, both front and back anchors are engaged with the tubular and do not allow for its longitudinal shrinkage, then the wall shrinkage may be equal to the degree of the radial expansion. It is to be understood that the performance characteristics of the expanded tubular, such as burst and collapse resistance, directly relate to the tubular wall thickness. In an embodiment, a tubular expansion apparatus includes a two anchor expansion system that provides for exit of an expansion swage from the tubular at the end of the expansion process and maximizes the performance characteristics of the expanded tubular.
In an embodiment, the tubular expansion apparatus provides for radial expansion of a tubular. The tubular expansion apparatus includes two anchors with at least one anchor axially movable relative to the other anchor while both anchors are engaged with the inner diameter of the tubular, an expansion swage, and an actuator capable of providing a suitable force for axial movement of the expansion swage inside the expandable tubular to plastically radially expand the tubular. In an embodiment, the tubular expansion apparatus includes an anchoring device. The anchoring device includes at least one anchor capable of axial displacement relative to the other anchor while both anchors are engaged with the inner diameter of the tubular. In an embodiment, two stoppers are positioned on each side of the at least one anchor, and a spring is positioned between one of the stoppers and the at least one anchor. In embodiments, one of the anchors is positioned in front of the expansion swage and the other anchor in back of the expansion swage, which may allow the expansion swage to be positioned outside the tubular before expansion and may also allow for the exit of the expansion swage out of the tubular at the end of the expansion process. The length of axial movement of the at least one anchor between stoppers is selected to allow for longitudinal shrinkage of the tubular during its radial expansion, which may result in improved performance of the expanded tubular.
As illustrated in
As further illustrated in
The configuration of the expansion apparatus shown in
As further illustrated in
Combining equations (1) and (2) yields equation (3).
Thus, the minimum distance for sliding of anchor 110 between end position stopper 111 and end position stopper 109 may not be less than that defined by equation (3).
For instance, in regards to a tubular expansion apparatus with an expansion stroke of actuator, L=5 ft, and expansion ratio of radial expansion ε=25%, the minimum distance for sliding of anchor 110 is Δ=10.5 in.
As shown in
It is to be understood that tubular expansion apparatus 5 may be used to expand either perforated or non-perforated tubulars or tubulars that include portions of both, since pressure automatically increases or decreases to provide the expansion forces.
It is to be further understood that tubular expansion apparatus 5 includes at least one anchor capable of a limited longitudinal displacement with regard to other anchors while all anchors are engaged with the inner diameter of tubular 100, but, in alternative embodiments, tubular expansion apparatus 5 may be employed in various different ways. For instance the anchors may be either hydraulically operated or mechanically operated one way anchors, with the anchor having a limited longitudinal displacement positioned either in the front or in the back of expansion swage 105.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
This application is a non-provisional application that claims the benefit of U.S. Application Ser. No. 60/791,081 filed on Apr. 12, 2006, which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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60791081 | Apr 2006 | US |