XU, Richard YingQing (11711 Rivergroove Ct, Tomball, Texas, 77377, US)
|What is claimed:
1. An expandable screen assembly comprising:
a tubular; and
a plurality of screens in operable communication with the tubular each of the plurality of screens being configured to radially expand in response to a same force longitudinally compressing the plurality of screens.
2. The expandable screen assembly of claim 1, wherein longitudinal forces needed to radially expand the plurality of screens varies from one of the plurality of screens to another the plurality of screens.
3. The expandable screen assembly of claim 1, wherein forces needed to radially expand each of the plurality of screens increases sequentially along a longitudinal direction.
4. The expandable screen assembly of claim 3, wherein the sequential increases in force increase in an uphole direction.
5. The expandable screen assembly of claim 1, wherein a first end of one of the plurality of screens is stationary relative to the tubular and another end is movable relative to the first end.
6. The expandable screen assembly of claim 5, wherein a plurality of screens nearer to the first end are configured to expand before a plurality of screens further from the first end.
7. The expandable screen assembly of claim 5, wherein a plurality of screens nearer to the first end are structurally weaker than a plurality of screens further from the first end.
8. The expandable screen assembly of claim 7, wherein structural weakness is due at least in part to radial thicknesses of the plurality of screens.
9. The expandable screen assembly of claim 5, wherein the plurality of screens are configured to expand sequentially starting with a screen nearest the first end and proceeding to a screen furthest from the first end.
10. The expandable screen assembly of claim 5, wherein a plurality of screens that are nearer to the first end have deformable portions with greater longitudinal dimensions than a plurality of screens further from the first end.
11. The expandable screen assembly of claim 1, wherein each of the plurality of screens prior to being radially expanded has a greater radial dimension near a longitudinal center thereof than at locations further from the longitudinal center.
12. The expandable screen assembly of claim 1, wherein the expandable screen assembly is employable within a wellbore.
13. The expandable screen assembly of claim 1, wherein the plurality of screens, when expanded, are configured to contact walls of a structure surrounding the expandable screen assembly even though dimensions of radial expansion needed to contact the walls varies.
14. The expandable screen assembly of claim 1, further comprising a piston in operable communication with the plurality of screens and the tubular configured to compress the plurality of screens in response to pressure applied thereagainst.
15. The expandable screen assembly of claim 14, further comprising a plug seat in operable communication with the tubular configured to allow pressure to build against the piston when a plug is seated against the plug seat.
16. The expandable screen assembly of claim 1, wherein the tubular is perforated.
17. The expandable screen assembly of claim 1, wherein the plurality of screens are configured to center the tubular within a structure surrounding the plurality of screens when the plurality of screens are radially expanded.
18. A method of expanding a plurality of screens comprising:
simultaneously longitudinally compressing the plurality of screens with a same load; and radially expanding each of the plurality of screens sequentially.
19. The method of expanding a plurality of screens of claim 18 wherein the sequentially radially expanding of the plurality of screens progresses in an uphole direction.
20. The method of expanding a plurality of screens of claim 18 wherein the longitudinally compressing is in response to building pressure against a piston in operable communication with the plurality of screens.
PLURALITY OF SCREENS
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Application No. 12/956,130, filed on November 30, 2010, which is incorporated herein by reference in its entirety.
 Filtering contaminates from flowing fluids is a common exercise in systems involved in transportation of fluids. Many such systems employ screens as the filtering mechanism. Screens that expand to substantially fill an annular gap between concentric tubulars, for example, is another common practice. Some of these systems use swaging equipment to radially expand the screen. Although such equipment serves its purpose it has limitations, including a limited amount of potential expansion, complex and costly equipment and an inability to expand to fill a space that varies over a longitudinal dimension. Apparatuses and methods that overcome these and other limitations with existing systems are therefore desirable to operators in the field.
 Disclosed herein is an expandable screen assembly. The screen assembly includes, a tubular, and a plurality of screens in operable communication with the tubular each of the plurality of screens is configured to radially expand in response to a same force longitudinally compressing the plurality of screens.
 Further disclosed herein is a method of expanding a plurality of screens. The method includes, simultaneously longitudinally compressing the plurality of screens with a same load and radially expanding each of the plurality of screens sequentially.
BRIEF DESCRIPTION OF THE DRAWINGS
 The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
 FIG. 1 depicts a cross sectional view of an expandable screen assembly disclosed herein in an unexpanded configuration;
 FIG. 2 depicts a cross sectional view of the expandable screen assembly of FIG. 1, in an expanded configuration; and  FIG. 3 depicts a cross sectional view of a portion of the expandable screen assembly of FIG. 1.
 A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
 Referring to Figures 1 and 2, an embodiment of an expandable screen assembly disclosed herein is illustrated generally at 10. The expandable screen assembly 10 includes, a tubular 14 and a plurality of screens 18A-18C that surround the tubular 14. The illustrated embodiment employs three of the screens 18A-18C while any number of the screens 18 is contemplated. The screens 18 are configured to radially expand when longitudinally compressed. All of the screens 18 in the expandable screen assembly 10 are longitudinally compressed by a same compressive arrangement, discussed in more detail below. As such they all experience a substantially same longitudinally compressive force. Differences in construction between each of the screens 18A-18C causes the screens 18A- 18C to expand at different compressive forces. As such, the screens 18A-18C can be made to expand in a preferred order. For example, the screens 18A-18C illustrated herein are configured to expand in sequence from the most downhole screen 18A toward the most uphole screen 18C as the compressive force is increased.
 Physical parameters of the screens 18A-18C can be selected to control an order of expansion of the screens 18A-18C. For example, the screens 18A-18C can be fabricated to have different values of structural weakness from one another, through the use of different materials, different material properties or different dimensions of specific features of each of the screens 18A-18C. In order to assure that the screen 18A expands at a lower compressive force than the screen 18B, for example, a wall thickness dimension 22A of the screen 18A can be made smaller than a wall thickness dimension 22B of the screen 18B. All other things being equal the smaller dimension 22 A will cause the screen 18A to expand at a lower compressive force than the screen 18B having the larger dimension 22B. Alternately, or in addition to having different wall thickness dimensions 22A, 22B, deformable portions 24A-24C of the screens 18A-18C can have different longitudinal lengths 26A-26C from one another. The longer the longitudinal dimension 26 A of the most downhole screen 18A will cause it to radially expand at lower compressive forces than the screens 18B, 18C that have smaller longitudinal dimensions 26B, 26C.  Having the screen 18A-18C radially expand in a specific sequence can be beneficial for various reasons. One such reason being to avoid longitudinally moving an already expanded screen relative to a structure surrounding the screens 18A-18C such as walls 30 of a borehole 34 in an application employed in the borehole 34 in an earth formation 36, for example. The screens 18A-18C are longitudinally slidably engaged on an outer surface 38 of the tubular 14. In this embodiment, a downhole end 42 of the screen 18A abuts a shoulder 46 on a downhole end 50 of the tubular 14. A piston 54 is movably engaged with the tubular 14 in response to pressure within a chamber 58 defined between a sleeve 62 sealingly slidably engaged with tubular 14 via seals 66, shown herein as o-rings. The piston 54 is urged in a downhole direction relative to the tubular 14 in response to pressure within the chamber 58. The urging force of the piston 54 simultaneously compresses all of the screens 18A-18C between the piston 54 and the shoulder 46.
 Since each of the screens 18A-18C is longitudinally compressed during radial expansion thereof, screens 18B and 18C move downhole relative to the tubular 14 in response to radial expansion of the screen 18 A. If either of the screens 18B or 18C were to radially expand into contact with the walls 30 before the screen 18A radially expanded, then surfaces 70B, 70C of the screens 18B, 18C respectively would scrape along the walls 30 while moving in a downhole direction during longitudinal compression of the screen 18 A. Such scraping could damage the screens 18B, 18C and should therefore be avoided. By having the screen 18A nearest to the stationary shoulder 46 expand first followed by the screen 18B next closest to the shoulder 46, and so on, scraping of screens 18B, 18C against the walls 30 can be avoided. Although the embodiment illustrated has the screens 18A-18C expand sequentially from a furthest downhole screen 18A first toward the furthest uphole screen 18C, it should be understood that alternate embodiments could just as well have this sequence inverted.
 Once one of the screens 18A-18C begins to radially expand forces required to continue radially expanding it further will be less than those required to begin the expansion until the expansion is complete. The expansion is complete when the screen 18A-18C encounters an obstacle, such as the walls 30, that prevents further expansion, or the screen 18A-18C has expanded as far as it is capable of expanding. Regardless of the cause of the completion, after completion the screen 18A-18C will begin supporting greater longitudinal loads thereacross. These greater loads, being transferred through all of the screens 18A-18C will cause the next structurally weakest of the screens 18A-18C to begin expanding.  The structure of the foregoing expandable screen assembly 10 allows each of the screens 18A-18C to fully radially expand into contact with the walls 30 even if the walls 30 are located at varying dimensions from the surfaces 70A-70C prior to expansion thereof. This characteristic of the screen assembly 10 is beneficial in certain downhole applications where contact between the screens 18A-18C and the walls 30 provide structural support to the walls 30 and helps avoid erosion that could otherwise occur due to longitudinal fluid flow between the surfaces 70A-70C and the walls 30 if a gap were allowed to exist therebetween.
 Perforations 74 in the tubular 14 in the embodiment in the Figures permits fluid flowing through the screens 18A-18C to also flow through the perforations 74 and into an inside 78 of the tubular 14. Once fluid is located at the inside 78 it is able to flow longitudinally through the tubular 14.
 Although many actuators are available that could provide actuation forces sufficient to deform the screens 18A-18C, such as electric motor actuators, shape memory alloy actuators, and hydrostatic pressure actuators, for example, the piston arrangement discuss above will be elaborated on further herein. One way to build pressure within the chamber 58 is to provide the pressure from a remote location, such as from surface, through the tubular 14. A port 82 through the tubular 14 provides fluid communication between the inside 78 of the tubular 14 and the chamber 58. A plug 86, illustrated here as a ball, is sealable with a seat 90 to allow pressure to be build thereagainst while preventing the fluid from escaping through the perforations 74. The ball 86 can be dropped or pumped from a remote location, such as surface, to the seat 90. Upon completion of expansion of the screens 18A-18C the ball 86 can be removed from the seat 90 via methods, such as, dissolving the ball 86, milling or drilling the ball 86, pumping the ball 86 through the seat 90 via deformation of the ball 86, the seat 90 or both, and by floating the ball 86 back from where it came via reverse flow through the tubular 14.
 An optional check valve 92, positioned within the port 82, can maintain pressure within the chamber 58 to keep the screens 18A-18C in their expanded configurations even after pressure within the inside 78 of the tubular 14 has been reduced. Alternately, other means (not shown), such as a ratcheting mechanism could be employed to mechanically lock the piston 54 at a position maintaining the screens 18A-18C in their expanded configurations after pressure within the inside 78 of the tubular 14 has been reduced.
 Referring to Figure 3, one of the plurality of screens 18A-18C, is illustrated alone in greater detail. The deformable portions 24A-24C of the screens 18A-18C are configured to radially expand in response to longitudinal contraction thereof. In this embodiment, the deformable portions 24A-24C have larger radial dimensions 94A-94C near longitudinal centers 98 A-98C of each of the screens 18 A- 18C respectively thereof than radial dimensions 102 at locations 106 displaced further longitudinally from the longitudinal centers 98A-98C. Although the shape of the surface 70A-70C disclosed herein approximates a radial arc, other shapes are contemplated as long as they meet the criteria laid out above. This criterion primarily assures that the surfaces 70A-70C of the screens 18A-18C deform radially outwardly in response to longitudinal compression thereof. Flanges 104, on either end of the screens 18A-18C have radial dimensions 105 that are greater than the radial dimensions 94A- 94C to provide protection for the surfaces 70A-70C against abrasion during running into the borehole 34.
 The screens 18A-18C disclosed herein, in addition to providing support to the walls 30 of the borehole 34 also tend to center the tubular 14 radially within the borehole 34 in response to being radially expanded into engagement therewith.
 While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.
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