Not applicable.
Not applicable.
The present invention generally relates to a liner running system for placing liners in well bores traversing earth formations. More particularly, the present invention relates to a liner running system comprising a liner running tool having an outer diameter less than or equal to the inner diameter of a liner being run into the well bore, and a latch sleeve having a wall thickness that is substantially the same as the wall thickness of the liner.
When drilling or completing wells that traverse earth formations, an upper portion of the primary well bore is drilled from the earth's surface to a selected depth, and then lined with a first section of pipe, commonly referred to as surface casing. The surface casing is then cemented into place in the well bore. The next succeeding section of the primary well bore is drilled to a selected depth below the surface casing and then lined with a string of pipe, commonly referred to as a liner. For each succeeding section of well bore that is drilled, a liner string is installed into the open borehole, below the surface casing or a previously installed liner string. During this process, each liner string may be cemented into place in the well bore.
Once the primary well bore is drilled and lined, a secondary well bore, such as a lateral well bore, for example, may be drilled and also lined with a liner. To perform a liner installation in either a primary or a secondary well bore, a running tool is releasably attached to a liner string. The running tool is connected to a work string or drill pipe that lowers the liner from the earth's surface into the open borehole below the surface casing or a previously installed liner string. The liner string may be rotated via the running tool to clear any obstructions in the borehole and to reduce friction as the liner string is lowered toward the bottom of the borehole.
Each liner string is connected at its upper end to a tubular liner hanger or another type of connection tubular, such as a lateral tube that extends between a primary well bore and a secondary well bore. The liner is lowered on the running tool via the work string until the liner hanger or connection tubular is adjacent to or near the lower end of the surface casing or a previously installed liner string. Then the liner hanger is set to engage the surrounding pipe wall and support the weight of the liner. Alternatively, the connection tubular is attached to the lower end of a previously installed casing or liner. Once the liner string is set, the liner may be cemented into place. The running tool is subsequently released from the liner and retrieved with the work string as it is withdrawn from the well bore.
Liner running tools conventionally include either hydraulic release means or mechanical release means. However, some liner running tools include both hydraulic and mechanical release means. Incorporating two different types of release means in a running tool is desirable given that trips into a well bore are expensive and time consuming. Thus, if the hydraulic release means fails, or if a liner must be reset, selective use of mechanical or hydraulic release means is desirable.
As described above, concentric liner strings are installed in the borehole as drilling progresses to increasing depths in a primary well bore or increasing lengths in a secondary well bore. Each new liner string must be run through the previously installed surface casing or liner string. Therefore, as successively smaller diameter liner strings are set, the flow area for the production of oil and gas is reduced. To maximize the production flow area, it is desirable to install a liner string with as large a diameter and length as possible so that the bottom of the formation can be reached with a comparatively larger diameter liner, thereby providing more flow area for the production of oil and gas.
However, traditional liner running tools have an outer diameter substantially the same size as the outer diameter of the liner string. Therefore, such running tools can only attach to the top of the liner string, and they act to “push” the liner string into the borehole. The longer the liner string, the more difficult it is for a traditional running tool to “push” the liner string into the borehole, especially in a lateral well bore. Therefore, it may be advantageous for a running tool to be releasably attachable to the liner string at any position along its length. Such a design would allow for the running tool to be connected near the lower end of the liner string, for example, so that a very long liner string may be “pulled” rather than “pushed” into an open borehole.
Further, some liner strings include features, such as slots or windows, which create structural weak points in the liner string. A running tool that could be attached to a liner string below a structural weak point, for example, would prevent stressing the weak point and buckling the liner string as it is being lowered into an open borehole. Therefore, a need exists for a liner running tool that may be releasably attached to a liner string at any location along its length.
The present invention is directed to a liner running system and method comprising a liner running tool that releasably attaches to a latch sleeve that, in turn, connects into a liner string. The liner running system may be used to deploy any downhole tubular.
In one aspect, a liner running system for placing a liner in a well bore comprises a latch sleeve connected to the liner and having a wall thickness substantially the same as the wall thickness of the liner, and a running tool releasably attached to the latch sleeve and having an outer diameter less than or equal to the inner diameter of the liner. In an embodiment, the latch sleeve may be connected into the liner at any location along its length. In another embodiment, the running tool is releasable from the latch sleeve via hydraulic actuation or mechanical actuation. Optionally, the liner running system may further comprise a swivel connected to the liner and having a wall thickness substantially the same as the wall thickness of the liner.
In another aspect, a method for placing a liner having a length, a wall thickness, and an inner diameter in a well bore comprises connecting a latch sleeve into the liner at any location along the length, releasably attaching to the latch sleeve a running tool having an outer diameter less than or equal to the inner diameter of the liner, running the liner into the well bore via the running tool, releasing the running tool from the latch sleeve, and removing the running tool from the well bore. In an embodiment, the method further comprises setting the liner. Running the liner into the well bore may comprise rotating the liner, pushing the liner, pulling the liner, or a combination thereof. Releasing the running tool from the latch sleeve may comprise applying a hydraulic force or a mechanical force.
In yet another aspect, a swivel connected into a liner comprises an upper portion and a lower portion rotatably connected to the upper portion, wherein the upper portion and the lower portion each have a wall thickness substantially the same as the wall thickness of the liner.
Other aspects and advantages of the invention will be apparent from the following description and the appended claims.
Certain terms are used throughout the following description and claims to refer to particular assembly components. This document does not intend to distinguish between components that differ in name but not function. 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 . . . ”.
Reference to up or down will be made for purposes of description with “up”, “upper”, or “upstream” meaning toward the earth's surface or toward the entrance of a well bore; and with “down”, “lower”, or “downstream” meaning toward the bottom of the well bore.
In the figures that follow, the cross-sectional side views of the liner running system should be viewed from left to right, with the upstream end on the far left side of the drawing and the downstream end on the far right side of the drawing.
Various embodiments of the liner running system and method will now be described with reference to the accompanying figures, wherein like reference characters are used for like features throughout the several views.
Referring now to
The body 21 includes recesses 48 adapted to partially contain torque keys 38. The torque keys 38 are held in place via a torque key retainer 39 that connects via threads 71 to the body 21. Corresponding with recesses 48 in the body 21 are slots 49 in the mandrel 25 within which torque keys 38 also partially reside.
An axial recess 73 is formed by the body 21, the mandrel 25, the piston retaining nut 33, and the nose 26, and contained within the axial recess 73 is an actuatable piston 31 connected via threads 75 to a piston lock ring retaining nut 34. A piston lock ring 24 is captured in a space between the piston 31, the piston lock ring retaining nut 34, and the mandrel 25. The piston 31 is in fluid communication with the flowbore 29 via port 28 that leads into a piston chamber 30 formed by O-rings 27 in the mandrel 25 and the piston 31. The piston lock ring retaining nut 34 and piston 31 are releasably coupled to the mandrel 25 by at least one hydraulic shear screw 36 that engages a groove 97 in the mandrel 25. The body 21 also contains a plurality of passages 52 adapted to receive latch dogs 22. As best shown in
Referring now to
In operation, the liner running system 100 may be used to run any downhole tubular into a primary or secondary well bore. To lower a liner 200 into a well bore, the running tool 20 is connected to the latch sleeve 40 as shown in
The running tool 20 is designed to selectively release the latch sleeve 40 by either hydraulic or mechanical actuation.
In one embodiment, a mechanical release is an emergency release operation performed only if the hydraulic release does not work.
Referring now to
In one embodiment, the swivel 10 comprises a top sub 16, a bottom sub 11, and a retainer nut 15. Retainer nut 15 is connected via threads 17 to bottom sub 11 and slidingly engages the top sub 16, thereby rotatingly connecting top sub 16 to bottom sub 11. Retainer nut 15 is disposed between an undercut area 18 and a shoulder 19 on the top sub 16, and O-ring 14 in the shoulder 19 assists in sealing the connection between the swivel components 16, 11, 15. In one embodiment, the retainer nut 15 comprises two semi-circular sections. During assembly of the swivel 10, spacers 13 may be provided (as best shown in
The foregoing descriptions of specific embodiments of the liner running system 100, as well as the systems and methods for running a liner 200 into a primary or secondary well bore were presented for purposes of illustration and description and are not intended to be exhaustive or to limit the liner running systems and methods to the precise forms disclosed. Obviously many other modifications and variations are possible. For example, the various components of the liner running tool 20, the latch sleeve 40, and the swivel 10 may be varied.
Accordingly, while various embodiments of the invention have been shown and described herein, modifications may be made by one skilled in the art without departing from the spirit and the teachings of the invention. The embodiments described here are exemplary only, and are not intended to be limiting. Many variations, combinations, and modifications of the invention disclosed herein are possible and are within the scope of the invention. The different teachings of the embodiments discussed herein may be employed separately or in any suitable combination to produce desired results. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow, that scope including all equivalents of the subject matter of the claims.
The present application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application Ser. No. 60/500,527 filed Sep. 5, 2003 and entitled “Liner Running System and Method”, hereby incorporated herein by reference for all purposes.
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Number | Date | Country | |
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20050051342 A1 | Mar 2005 | US |
Number | Date | Country | |
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60500527 | Sep 2003 | US |