Expandable screen jacket and methods of using same

[0002] The present inventions relate to sand-control apparatus for use in subterranean wells, and in particular contemplate improved configurations for radially expandable sand-control screen jacket apparatus and methods of using the same.

[0003] The control of the movement of sand and gravel into a well bore has been the subject of much importance in the oil production industry. The introduction of sand or gravel into the well bore commonly occurs under certain well conditions. The introduction of these materials into the well commonly causes problems including plugged formations or well tubing, and erosion of tubing and equipment. There have therefore been numerous attempts to prevent the introduction of sand and gravel into the production stream.

[0004] A common method to prevent the introduction of sand and gravel into the production stream has been a procedure known as gravel packing. In general, this involves placing selected sand or gravel into the annular space between the well bore and a base pipe introduced into the wellbore for that purpose. The base pipe contains perforations designed to allow well fluids to flow into the base pipe while excluding other material. A sand-control screen is commonly used in conjunction with a base pipe. An appropriately sized screen is commonly formed into a jacket and placed concentrically around the outside of the base pipe to prevent the entry of sand into the base pipe. Exemplary apparatus and methods of attaching a sand-control screen jacket to a base pipe are disclosed in U.S. Pat. No. 5,931,232, and in application Ser. No. 09/602,387, which are both assigned to this assignee and is incorporated herein for all purposes by this reference thereto.

[0005] One method of enhancing production in a well using a sand-control screen jacket includes causing the radial expansion of the base pipe and surrounding screen jacket by forcing a mechanical expansion tool through the base pipe. Examples of deformable well screens are disclosed in U.S. Pat. Nos. 5,901,789 and 6,012,522, to Donnelly. These methods use screens and methods to control the screen mesh opening size.

[0006] It is important that an expandable sand-control screen maintain its integrity throughout its entire length. Any voids in the screen that permit the entry of sand generally lead to erosion, which in turn allows the entry of more sand into the production stream. Wellbores with irregular sides or a particularly tortuous path, in order to allow sufficient clearance for insertion, generally require sand-control screen jackets having a diameter much smaller than the diameter of the wellbore. The radial expansion of a small diameter sand-control screen jacket into a much larger diameter wellbore can be particularly problematic. Extreme levels of expansion can lead to loss of integrity of the screen jacket connections with the base pipe. The result is the introduction of sand into the production stream and all of the attendant problems associated therewith.

[0007] Due to the aforementioned problems with the introduction of sand and gravel into the production stream, a need exists for apparatus and methods ensuring a radially expandable sand-control screen capable of withstanding a high degree of expansion while retaining sand-controlling connections with the base pipe.

[0008] The invention provides apparatus and related methods for constructing and using a radially expandable sand-control screen jacket assembly for use in a subterranean well. The screen-jacket assembly has at least two overlapping screen elements surrounding a base pipe, with a longitudinal sand-control seal between screen elements. The assembly maintains sand control after being radially expanded.

[0009] According to different aspects of the invention, the screen jacket assembly has two, three, four, or more overlapping screen elements.

[0010] According to another aspect of the invention, the assembly is encased in a screen shroud.

[0011] According to still another aspect of the invention, the inner screen element edges and outer screen element edges are substantially helical with respect to the to axis of the base pipe.

[0012] According to another aspect of the invention, the outer screen element is biased toward the inner screen element.

[0013] The accompanying drawings are incorporated into and form a part of the specification to illustrate several examples of the present inventions. These drawings together with the description serve to explain the principals of the inventions. The drawings are only for the purpose of illustrating preferred and alternative examples of how the inventions can be made and used and are not to be construed as limiting the inventions to only the illustrated and described examples. The various advantages and features of the present inventions will be apparent from a consideration of the drawings in which:

[0014] FIG. 1 is a top perspective view of a radially expandable sand-control screen jacket;

[0015] FIG. 2 is a transverse cross-sectional view of the radially expandable sand-control screen jacket taken along line 2—2 of FIG. 1;

[0016] FIG. 3 is a transverse cross-sectional view of the radially expandable sand-control screen jacket of FIG. 2 in an expanded state;

[0017] FIG. 4 is a top perspective view of an alternative embodiment of a radially expandable sand-control screen jacket in an unexpanded state; and

[0018] FIG. 5 is a transverse cross-sectional view of an alternative embodiment of the inventions.

[0019] The present inventions are described by reference to drawings showing one or more examples of how the inventions can be made and used. In these drawings, reference characters are used throughout the several views to indicate like or corresponding parts.

[0020] In the description which follows, like or corresponding parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the invention. In the following description, the terms “upper,” “upward,” “lower,” “below,” “downhole”, “longitudinally” and the like, as used herein, shall mean in relation to the bottom, or furthest extent of, the surrounding wellbore even though the wellbore or portions of it may be deviated or horizontal. Correspondingly, the “transverse” orientation shall mean the orientation perpendicular to the longitudinal orientation. “Longitudinally moveable”, in particular, means movement with a longitudinal component, although a transverse component may be present as well. In the discussion which follows generally cylindrical well, pipe and tube components are assumed unless expressed otherwise. The term “sand-control” used herein means the exclusion of particles larger in cross section than a chosen size, whether sand, gravel, mineral, soil, organic matter, or a combination thereof.

[0021] Referring now to FIGS. 1-5, the general structure of a radially expandable sand-control apparatus 10 utilizing the present inventive concepts is shown. A base pipe 12 is connected to a pipe string (not shown) used in a subterranean well. The base pipe 12 has a plurality of perforations 14 through which fluids in the well enters the interior of the base pipe 12. The number and configuration of the perforations 14 is not critical to the invention so long as a balance between fluid production and pipe integrity is maintained. The sand-control screen jacket assembly 16 concentrically surrounds the base pipe 12. A screen shroud 18 with perforations 19 may surround the screen jacket assembly 16. It is important to note that the exact ordering and number of components of the screen jacket assembly are not crucial to the invention except as to the features further discussed below. For example, or multiple screens with or without intervening layers of packing medium may be included. The screen shroud 18 may also be omitted or replaced by an additional screen.

[0022] Now referring primarily to FIG. 2, expandable sand-control apparatus 10 is shown in this cross-section view taken along line 2-2 of FIG. 1. The screen jacket assembly 16 has an inner screen element 22 attached at its longitudinal edges 24 to the base pipe 12. A base pipe joint 13 is formed at the point of attachment. The joint is preferably spot welded, or may be screwed, pinned, or on slidable channels, and is not necessarily sand-controlling. The inner screen element 22 and outer screen element 26 are preferably made of a screen, but may be made of other relatively low friction material such as “TEFLON”®, a registered trademark, or perforated sheet metal such as nickel or nickel alloy.

[0023] An outer screen element 26, substantially encircles the inner screen element 22. Longitudinal end portions 27 of outer screen element 26 at least partially overlap longitudinal end portions 29 of the inner screen element 22. The outer screen element may optionally completely encircle the inner screen element. The outer screen element 26 is preferably manufactured with a bias toward closing its edges 28 in the direction of the inner screen 22. The outer screen element edges 28 each have a seal element 30. The seal element 30 is preferably made from an elastomeric material but may be made from wire or a hollow wire designed to collapse in operation and seal upon radial expansion of the sand-control apparatus 10 as further discussed below. The contact between the seal elements 30 and the inner screen element 22 forms sand-control joints 32 sufficiently close-fitting after expansion to exclude sand particles of a size to also be excluded by the screen elements 22, 26, but not necessarily fluid tight. The joints 32 may or may not be sand-controlling prior to expansion. As the base pipe 12 and screen jacket assembly 16 are radially expanded, the overlapping portions 27, 29 of the joints 32 slide transversely with respect to one another while maintaining sand-controlling fits.

[0024] Now referring primarily to FIG. 3, in operation, the sand-control apparatus 10 is expanded in the conventional manner, typically with an expansion cone (not shown). The base pipe 12 expands, as do the inner screen element 22, and the outer screen element 26, and screen shroud 18, if included. The components come to rest in the position drawn with seal element 30 in contact with inner screen element 22. If a hollow wire seal element 30 is used, the hollow wire collapses or partially collapses and maintains a sand-controlling seal. As the base pipe 12 and screen jacket assembly 16 are radially expanded, the overlapping portions 27, 29 of the sand-controlling joints 32 slide transversely with respect to one another, maintaining their sand-controlling fits. It is not critical to the invention for the base joints 13 to maintain their attachment to the expanded base pipe 12. The expanded sand-control apparatus 10 may be used with or without packing medium (not shown) in the annular space 36 between the expanded screen jacket assembly and the wellbore wall 15.

[0025] Referring to FIG. 4, an alternative embodiment of the invention is shown wherein the inner and outer screen elements 22 and 26 are in helical form. In this embodiment, sand-control screen jacket assembly 16 surrounds base pipe 12. The sand-control screen jacket assembly may include a screen shroud (not shown). Inner screen element 22 is in helical form and is affixed along longitudinal edges 24 to the base pipe 12 forming base pipe joints 13. Outer screen element 26 substantially encircles the inner screen element 22 and is preferably spring-biased toward the inner element 22. Outer screen edges 28 each have a seal element 30. Longitudinal end portions 27 of the outer screen element 26 at least partially overlap the longitudinal end portions 29 of the inner screen element 22. The contact between the seal elements 30 and the inner screen element 22 forms sand-control joints 32 sufficiently close-fitting after expansion to exclude sand particles of a size to also be excluded by the screen elements 22, 26, but not necessarily fluid tight. The joints 32 may or may not be sand-controlling prior to expansion. As the base pipe 12 and screen jacket assembly 16 are radially expanded, the overlapping portions 27, 29 of the joints 32 slide transversely with respect to one another, maintaining their sand-controlling fits.

[0026] Referring primarily to FIG. 5, an alternative example of the invention is shown wherein the invention is embodied with two inner screens 22a, 22b, and two outer screens 26a, 26b. Seal elements 30 are included where the longitudinal edges 28 of the outer screens 26 contact the inner screens 22. Also in this embodiment, the inner and outer screen elements 22, 26, may be helical in form. The seal elements 30 are preferably made from an elastomeric material but may be made from a wire or hollow wire designed to collapse and seal upon radial expansion of the sand-control apparatus 10. The contact between the seal elements 30 and the inner screen element 22 forms a sand-control joint 32 sufficiently close-fitting after expansion to exclude sand particles of a size to also be excluded by the screen elements 22a,b, 26a,b, but not necessarily fluid tight. The joints 32 may or may not be sand-controlling prior to expansion. As the base pipe 12 and screen jacket assembly 16 are radially expanded, the overlapping portions 27, 29 of the joints 32 slide transversely with respect to one another, maintaining their sand-controlling fits. The outer screen elements 26a, 26bare preferably manufactured with a spring-bias toward closing their longitudinal edges 28 in the direction of inner screens 22aand 22b. The screen elements may be made from materials known in the art for downhole screens.

[0027] The embodiments shown and described above are only exemplary. Many details are often found in the art such as: seal element or screen size, configurations and materials. Therefore, many such details are neither shown nor described. It is not claimed that all of the details, parts, elements, or steps described and shown were invented herein. Even though numerous characteristics and advantages of the present inventions have been set forth in the foregoing description, together with details of the structure and function of the inventions, the disclosure is illustrative only, and changes may be made in the detail, especially in matters of shape, size and arrangement of the parts within the principles of the inventions to the full extent indicated by the broad general meaning of the terms used in the attached claims.

[0028] The restrictive description and drawings of the specific examples above do not point out what an infringement of this patent would be, but are to provide at least one explanation of how to make and use the inventions. The limits of the inventions and the bounds of the patent protection are measured by and defined in the following claims.