Patent Publication Number: US-9416633-B2

Title: Screen assembly

Description:
BACKGROUND 
     Screens and other filtering assemblies are ubiquitous in the downhole drilling and completions industry. These assemblies are primarily used to filter solids or particulate matter while enabling the production of fluids such as hydrocarbons. Due at least partially to their prevalence in the industry, advances and alternatives in downhole screen assemblies are always well received. 
     SUMMARY 
     A screen assembly, comprising one or more screen members that correspondingly form one or more flow paths, the one or more flow paths discrete from a tubular with which the one or more screen members are associated, but in fluid communication with an axial passageway of the tubular. 
     A screen assembly, comprising a plurality of screen members arranged at a same longitudinal position along a tubular, each of the screen members having a discrete closed shape that forms one of a plurality of discrete flow paths corresponding to the plurality of screen members. 
     A method of using a screen assembly, comprising positioning the screen assembly in a borehole, the screen assembly having one or more screen members discretely arranged with respect to a tubular having an axial passageway, the one or more screen members correspondingly forming one or more flow paths that are discrete from the tubular; and communicating fluid through the one or more screen members to the axial passageway via the one or more flow paths. 
    
    
     
       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  illustrates a screen assembly installed in a borehole according to one embodiment disclosed herein; 
         FIG. 2  is a cross-sectional view of the assembly of  FIG. 1 ; 
         FIG. 3  illustrates a screen assembly according to one embodiment disclosed herein; 
         FIG. 4  is a cross-sectional view of the assembly of  FIG. 3 ; 
         FIG. 5  illustrates a coupling of the screen assembly of  FIG. 1 ; and 
         FIG. 6  is a coupling for a screen assembly according to one embodiment disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
     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 now to  FIGS. 1 and 2 , a screen assembly  10  is illustrated for filtering solids or particulates while enabling the production of desired fluids, e.g., of hydrocarbons, from a subterranean formation via a borehole  12 . It is to be appreciated at the outset that for succinctness in discussion the assembly  10  is illustrated as a conglomeration of embodiments including several features that may be used separately or together in any combination. In general, the screen assembly  10  includes one or more discrete screen members  14  arranged circumferentially about a tubular of a tubular string  16 , which is, e.g., a production string. By tubular string it is meant one or more tubulars disposed together. The screen members  14  include a filter portion, which can be any desired filtering material, medium, or configuration, such as mesh, slots, wire-wrap, permeable foam, or combinations thereof. In one embodiment, the filtering material is wrapped or disposed about a perforated inner tubular or mini-base pipe to form the screen members  14 . It is to of course be appreciated that in other embodiments the screen members  14  can be formed solely from a filter material without use of an inner tubular. The tubular string  16  includes one or more ports or openings (discussed in more detail below) or is otherwise in fluid communication with the screen members  14  for enabling production of fluids filtered by the screen assembly  10 . 
     It is evident to those of ordinary skill in the art from even a cursory review of the drawings that the screen assembly  10  differs from traditional screens, in which a filter is concentrically wrapped at least partially about a base pipe or other tubular to form a radial flow gap bounded between the screen and the tubular about which the screen is wrapped. Instead of this traditional arrangement, the screen members  14  are arranged as discrete members that form discrete flow paths therein. By “discrete” it is meant that the screen members  14  each form a closed shape defining a flow path  18  therein that is separate from the other screen members  14  and from the tubular string  16 . It is noted that a pattern formed by all of the screen members  14  may encircle the tubular string  16 , but that the tubular string  16  is not enclosed within any individual one of the screen members  14 . In this way, the flow paths  18  are discrete from and not defined by the tubular string  16 . For example, the screen members  14  in  FIG. 2  are shown in a circular pattern, designated by a dashed line  20 , surrounding the tubular string  16 , but the tubular string  16  is not enclosed by any individual one of the screen members  14 . Of course, screen members in other embodiments could be arranged according to other patterns. It is additionally to be recognized that the screen assembly  10  differs from traditional screens in that it includes a plurality of the discrete screen members  14  at a same longitudinal or axial position within the borehole  12  and/or along the length of the string  16 . 
     Additionally, by being discrete members, each of the screen members  14  in the illustrated embodiment, and correspondingly each of the flow paths  18 , is offset or nonconcentric with respect to the tubular string  16 . It is also noted that despite the screen members  14  and the associated flow paths  18  each being nonconcentric with the tubular string  16 , the pattern formed by discretely positioning the screen members  14  about the tubular string  16 , may be concentric with respect to the tubular string  16 . That is, for example, the pattern  20  in  FIG. 2  is circumferentially and concentrically positioned about the tubular string  16 , while the axes of each of the screen members  14 , e.g., an axis  22  of an exemplary one of the screen members  14 , are each offset from an axis  24  of the tubular string  16 . 
     The screen members  14  are coupled to the tubular string  16  via couplings  26 , which have receptacles  28  configured to receive the screen members  14 . The screen members  14  are engagable with the receptacles  28  via threads, ratcheting, grooves, force fitting, welds, etc., or in any other suitable manner. In one embodiment, the receptacles  28  are open on both ends for connecting adjacent ones of the screen members  14 , while in other embodiments the receptacles  28  are capped off opposite to their securement with the screen members  14 . For example, a representative one of the receptacles  28 , designated with the numeral  28   a , is secured at one end to a first representative one of the screen members  14 , designated with the numeral  14   a , and at the opposite end to a second representative one of the screen members, designated with the numeral  14   b . Another representative one of the receptacles  28 , designated with the numeral  28   b , has a capped end  30  for sealing off the flow path  18  through the receptacle  28   b.    
     The screen members  14  can be arranged to create a gap  32  between each circumferentially adjacent pair of the screen members  14 . In one embodiment, the gaps  32  provide fluid about the screen members  14 . Traditional screens are typically spaced some minimum distance from the borehole wall in order to provide sufficient fluid flow into the screen, e.g., during production, and about the screen, e.g., during gravel packing, fracturing, or other borehole treatments or stimulations. Accordingly, in one embodiment, the fluid flow provided by the gaps  32  enables the screen members  14  to be positioned relatively closer to the borehole  12  than a traditional screen could be positioned, thereby enabling the borehole  12  to be more efficiently drilled with a smaller diameter. In another embodiment, the gaps  32  provide for the flow of fluid (e.g., proppant, slurry, injected chemicals, acid, etc.) past, around, or about the screen assembly  10 , e.g., for gravel or frac packing, fracturing, or other treatment or stimulation operations. 
     Additionally, as shown in  FIGS. 1 and 2 , the gaps  32  can be utilized to house and/or protect a control line, cable, instrumentation line, etc. (generally “control line”). The control line can be a hydraulic control line, fiber optic cable, electrical signal conductor, etc., arranged for enabling signal and/or power communication to and/or from the downhole environment. For example, a control line  34   a  is shown located in one of the gaps  32  between an adjacent pair of the screen members  14  in  FIGS. 1 and 2 . The line  34   a  is generally maintained and protected within its corresponding one of the gaps  32  during run-in, completion, and production. Even though the line  34   a  is generally protected, it remains open to downhole fluids, thereby enabling borehole fluids and downhole operations to be monitored by the line  34   a  and/or via sensors attached thereto, if desired. As another example, a control line  34   b  is illustrated passing through one of the screen members  14 , thereby providing protection to the control line  34   b . A clip, adhesive, fastener, or other device or mechanism could be used for holding the control lines  34   a  and/or  34   b  in their respective areas. 
     It is also to be appreciated that the gaps  32  could be used for holding or providing for a shunt tube or other tool or piece of equipment to be located and/or passed by the screen assembly  10 . Furthermore, ones of the screen members  14  could be used as shunt tubes to enable the conveyance of proppant, gravel, or slurry downhole. In one embodiment, one or more of the screen members  14  is replaced by a similarly shaped and sized blank tubular (e.g., not including a filtering material, perforations, or other openings in its circumferential surface) that is receivable in the receptacles  28  of the couplings  26  (the blank tube generally resembling any one of the screen members  14  and thus sufficiently represented in the drawings, although it is understood that the blank tube or shunt tube could take other forms). For example, in one embodiment, the blank tubular is used as a shunt tube to convey slurry or proppant to the borehole  12  or as a protective conduit for housing control lines, sensors, or other equipment. For example, in one embodiment, the screen assembly  10  is modified such that seven of the screen members  14  are included as described above, while an eighth is replaced by a section of blank pipe for protecting control lines, enabling slurry or other media to be conveyed downhole, etc. 
     The screen members  14  of the embodiment of  FIGS. 1 and 2  are shown having a circular cross-section. It is to of course be appreciated that the screen members  14  could take any other desired shape, e.g., polygonal, irregular, crescent or kidney-bean (e.g., to follow the contours of the tubular string  16 ), etc. It is also to be appreciated that the screen members  14  can be arranged in any desired pattern about the tubular string  16  and that they do not need to follow the circular pattern  20 . Moreover, size of the gaps  32  and/or spacing between the screen members  14  does not need to be consistent. For example, the screen members  14  in  FIGS. 1 and 2  are evenly, symmetrically, and/or regularly spaced about the circumference of the tubular string  16 . In other embodiments, the spacing between adjacent ones of the screen members  14  could be irregular or inconsistent. In some embodiments the pattern formed by the screen members  14  is asymmetrical, i.e., the screen members  14  wrap around only a portion of the circumference of the tubular string  16 , e.g., an assembly  36  in  FIG. 3  discussed below. The pattern formed by the members  14  can be concentrically or eccentrically included about the tubular string  16 . 
     As noted above, the screen assembly  36  includes the screen members  14  arranged in an asymmetric pattern about the tubular string  16 . By this it is meant that the screen members  14  of the assembly  36  are not evenly spaced and positioned about the tubular string  16 , but instead are grouped together at one side of the tubular string  16 . A coupling  38  is included for securing the screen members  14  of the assembly  36  to the string  16 . The ends of the screen members  14  opposite from the coupling  38  are illustrated as being open, although it is to be appreciated that these ends would be connected into another coupling or screen member, capped off, etc. Additionally, the ends of the screen members  14  are shown tapered or having reduced diameter than the body of the screen members  14 , which can assist in securing the screen members  14  in the receptacles of the couplings  26  and/or  38 . The tapered ends may be caused by the aforementioned inner tubulars or base pipes of the screen members  14 , e.g., a base pipe  40 , extending out from a filter portion  42  wrapped thereon. It is to of course be appreciated that the description of the assembly is generally application to those of the assembly  10  and that components and features of the assembly  36  can be used with or for the assembly  10 , and vice versa. 
     As shown in cross-section in  FIG. 4 , the coupling  38  is positioned with respect to one or more ports or openings  44  in the tubular string  16 , thereby providing fluid communication between the flow paths  18  and an axial passage  46  of the string  16 . The coupling  38  also includes a valve  48  having a valve member  50  that is movable within a valve chamber  52  in order to selectively enable fluid communication between the flow paths  18  and the axial passageway  46 . In the illustrated embodiment, the valve member  50  is controlled hydraulically via a control line  54  in fluid communication with the chamber  52 . That is, pressure can be communicated via the control line  54  to hold the valve member  50  in the closed configuration shown in  FIG. 4 . Upon relieving the pressure in the control line  54 , pressure from the downhole fluid entering the flow paths  18  through the screen members  14  will force the member  50  toward the line  54 , uncovering or opening the ports  44  and enabling production of the fluid through the axial passageway  46  of the string  16 . It is to be appreciated that the chamber  52  and the valve member  50  can be in communication with all of the screen members  14  of the assembly  36  (e.g., the member  50  resembling a sliding sleeve or arcuate member), selected ones or groups of the screen members  14 , or each of the screen members  14  could be provided separately with a valve member (e.g., the member  50  being generally cylindrical in shape). It is additionally to be appreciated that a valve member, e.g., a sliding sleeve, can be positioned within the axial passage  46  in order to selectively enable fluid communication. Additionally, the valve member  50  or any other valve member can be actuated mechanically, e.g., via a shifting tool or spring, electrically, e.g., via a motor or electromagnet, or in any other manner known in the art or otherwise. In one embodiment, a sliding sleeve having a seat is provided to receive a ball or plug dropped downhole and shifted by pressuring against the plug and seat in order to selectively open the ports  44 . 
       FIG. 5  shows one of the couplings  26  without the rest of the screen assembly  10 . From the view of  FIG. 5  it can be appreciated that one or more ports  56  in the couplings  26  can be positioned with respect to ports, e.g., the ports  44 , in the string  16 , similar to the coupling  38  in order to enable fluid communication between the flow paths  18  and the axial passageway  46 . Additionally, a valve, for example, any of the valves discussed above with respect to the assembly  36 , could be arranged with the coupling  26  to selectively enable fluid communication through the screen assembly  10 . One of the ports  56  could be provided for each of the screen members  14 , or multiple ones of the screen members  14  could be in fluid communication with single ones of the ports  56  via grooves or the like within the coupling  26 . 
       FIG. 6  illustrates a coupling  58  that also enables fluid communication between the flow paths  18  of the screen members  14  and the axial passageway  46  of the string  16 . Specifically, the coupling  58  includes receptacles  60  adapted to receive the screen members  14  and that terminate in ports  62 . The coupling  58  can be secured between two sections of the string  16 , e.g., at an end  64  (and an opposite end, hidden from view behind the receptacles  60 ), such that the ports  62  open directly into axial passageway  46  of the string  16 . The end  64  could be threaded, force fit, welded, or secured to the string  16  in some other manner. Alternatively, the ports  62  could be aligned with ports in the string  16 , e.g., resembling the ports  44 . 
     With knowledge that the filterable surface area of a cylindrical screen is measured as pi times diameter times length, the total filterable surface area of the screen members  14  of the assembly  10  can be set to equal or approximate that of a traditional screen of a given length by modifying the number and diameter of the screen members  14 . For example, there are eight of the screen members  14  in the illustrated embodiments, thus, by setting the diameter of each of the screen members  14  to be one-eighth that of a traditional screen, the total filterable surface area of the screen assembly  10  would approximate that of the tradition screen, assuming constant length. In this way, for example, eight of the screen members  14 , each having a one inch diameter, would approximate the same total filterable surface area as a traditional screen eight inches in diameter having the same length. Of course, any other number of the screen members  14  and/or diameters of the screen members  14  could be utilized and the size of screen members in the same assembly could also vary. 
     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.