Abstract:
An interventionless downhole screen that is resistant to plugging during run-in-hole operations and a method for remotely actuating the screen. The screen includes a perforated sleeve that is slideably disposed coaxially with a perforated tubular member. When running, the sleeve is in a closed positioned with its openings offset from the apertures in the tubular member, thereby blocking flow through the screened openings, while a check valve through the tubular member allows fluid ingress. To actuate for production, the tubular member is pressurized, which moves a piston into ratcheting engagement with the sleeve. A subsequent depressurization allows the piston to return to its original position, carrying with it the sleeve to an open position where the sleeve and tubing perforations are aligned for allowing fluid flow into the tubular member.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a U.S. National Stage patent application of International Patent Application No. PCT/US2013/040539, filed on May 10, 2013, the benefit of which is claimed and the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to completing and producing oil and gas wells, and specifically to a novel method and system for deploying a downhole screen. 
     2. Background Art 
     In the process of completing on oil or gas well, a tubular is run into the hole through which produced fluids will be communicated to the surface. Typically, this tubular includes a screen assembly that filters gravel, sand, and other particulate matter from entering the tubular. 
     When running this completion string into the well, the well may contain drilling mud, brine, or other fluid. Further, this fluid may be laden with rock, cutting chips, sand, and the like. Fluid tends to enter the empty tubular through the screen assembly, and such particulate can substantially plug the screen assembly by the time it has been lowered into the desired position. 
     Accordingly, it is desirable to provide a screen assembly that resists plugging during run-in-hole operations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in detail hereinafter on the basis of the embodiments represented in the accompanying figures, in which: 
         FIG. 1  is a longitudinal cross section of a downhole screen assembly according to a present embodiment, showing a tubular member with apertures formed through the wall, a sleeve slideably disposed about the tubular member with openings that correspond to the apertures, and an actuator that remotely moves the sleeve with respect to the tubular member; 
         FIG. 2  is an enlarged longitudinal cross section of the downhole screen of  FIG. 1 , showing detail of the actuator as actuation of the screen is first begun; 
         FIG. 3  is an enlarged longitudinal cross section of the actuator of  FIG. 2 , showing the body lock ring having been displaced and further engaged the sleeve under the influence of a pressurized interior; and 
         FIG. 4  is a perspective view of the body lock ring of the actuator of  FIG. 3 , showing an interior wall surface having ratchet teeth for unidirectional movement against ratcheting teeth of the slideable sleeve of  FIG. 3 ; 
         FIG. 5  is an enlarged longitudinal cross section of the actuator of  FIG. 3 , showing the sleeve moved to the open position after remote actuation. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a longitudinal cross section of a downhole screen assembly  10  for use within a well  8  according to a present embodiment. Screen assembly  10  includes a tubular member  12 , which may be cylindrical in shape. However, other tubing shapes, such as square tubing, may be used as appropriate. Tubular member  12  includes a plurality of apertures  14  for the intake of well fluids from an exterior or annular region  16  to the interior  18  during well production. Tubular member  12  may have a closed lower end  20  for terminating the bottom of the tubing string in the well. If multiple screen assemblies  10  are provided in a tubing string, only the lowest screen assembly would have a closed lower end. 
     According to an embodiment, screen assembly  10  includes a sleeve  30  having the same shape type as tubular member  12 , which preferably abuts but can be moved relative to tubular member  12 . Sleeve  30  is shown disposed about the exterior wall surface of tubular member  12 , but in an alternative arrangement (not illustrated), the tubular member could be disposed about the sleeve. Sleeve  30  includes a plurality of openings  32 , which correspond to apertures  14 . Sleeve  30  may have a closed lower end (not illustrated) if it is the last device in tubing string. 
       FIG. 1  shows sleeve  30  in a shut position where openings  32  are offset from apertures  14  to prevent fluid flow therebetween. In the embodiment illustrated, sleeve  30  can slide longitudinally along axis  24  with respect to tubular member  12 , and openings  32  are radially aligned with longitudinally offset from apertures  14 . However, in other embodiments (not illustrated), openings  32  may be radially offset instead of or in addition to longitudinally offset, and sleeve  30  is capable of rotating with respect to tubular member  12 . 
     Screen assembly includes a mesh, screen or filter  40  disposed so as to prevent sand, sediment, gravel, and other particulate matter of predetermined size from entering into the interior  18  of tubular member  12 .  FIG. 1  shows mesh  40  to be disposed about the exterior of sleeve  30 , but meshing  40  can be disposed within tubular member  12 , within apertures  14 , between tubular member and screen  30 , within openings  32 , or any combination of the above as would be known to one of ordinary skill in the art. 
     A actuator  50  is operatively connected between tubular member  12  and sleeve  30  which provides for remote, interventionless actuation from the surface of screen assembly  10  to move screen  30  with respect to tubular member  12  so that openings  32  align with aperture  14  to allow fluid flow into the interior  18 . In this manner, downhole screen assembly  10  can be run into a well  8  with sleeve  30  in a shut position, thereby preventing fluid flow into the screen assembly and minimizing the tendency for particulate matter to plug mesh  40 . Once screen assembly  10  has been lowered to the desired position within well  8 , sleeve  30  may be actuated to an open position to allow well production simply by pressurizing interior  18 , as is described below with respect to  FIGS. 2-5 . 
     Although actuator  50  is shown in  FIG. 1  as being located at the top of sleeve  30 , it may also be located the bottom or somewhere in the middle of sleeve  30 . 
       FIG. 2  is an enlarged longitudinal cross section of the downhole screen of  FIG. 1 , showing detail of actuator  50 . In a particular embodiment, actuator  50  includes a housing  52  with an inner cylindrical chamber  51 , through which tubular member  12  passes and in which a portion  31  of sleeve  30  is located. Sleeve portion  31  includes ratchet teeth  53 . A body lock ring  54  is provided within housing  52 , and it also includes ratchet teeth  56  that engage ratchet teeth  53  so as to allow axial movement of the body lock ring  54  with respect to sleeve portion  31  in one direction only as described in further detail below. 
     Body lock ring  54  is axially movable about tubular member  12  within chamber  51 . A first end  55  of body lock ring  54  acts as an annular piston face and is in fluid communication with the interior  18  of tubular member  12  via a conduit  60 . Body lock ring  54  includes inner and outer dynamic seals  57 ,  58 , for example grooves with seated o-rings, that seal against an outer wall section of tubular member  14  and in the inner wall of chamber  51  within housing  52 , respectively, yet allow relative movement of body lock ring  54 . The second end  59  of body lock ring  54  rests against a resilient member  62 , such as a coiled spring, which resists an increase of pressure acting on piston face  55 . 
     Conduit  60  also includes a check valve  64  that selectively connects the interior  18  to the exterior  16 . As illustrated, check valve  64  may include a ball  65  and a seat  66 , whereby the ball  65  is forced and seals against the seat  66  when the fluid pressure within the interior  18  is pressurized with respect to the pressure of the exterior  16 . When the pressure gradient is reversed, ball  65  lifts off of seat  66  and allows flow. Accordingly, when screen assembly is being run into the well, as shown in  FIG. 1 , well fluid can enter tubular member  12  through check valve  64  and conduit  60 , rather than through apertures  12  to reduce the risk of plugging the screen assembly. Although only one check valve  64  is illustrated, multiple check valves may be used as appropriate. 
       FIG. 2  depicts screen actuator  50  after the screen assembly has been run into the well and at the initial point in the actuation sequence where the interior fluid pressure has been raised to shut check valve  64 , thereby allowing the tubular member  14  to be pressurized at the surface, with a concomitant increase in pressure acting at piston face  55  of body lock ring  54 . 
     Referring now to  FIG. 3 , further increasing fluid pressure within interior  18  causes a greater force to be exerted on piston face  55  of body lock ring  54 , thereby compressing resilient member  62  and moving body lock ring  54  toward sleeve  30 . As body lock ring  54  moves toward sleeve  30 , ratchet teeth  56  are forced past and engage ratchet teeth  53 , as explained in greater detail below with reference to  FIG. 4 . 
       FIG. 4  is a perspective view of body lock ring  54  according to a particular embodiment. The first end  55  has a smaller internal diameter than the second end  59 . Near the first end  55 , a circumferential groove  68  is provided around the exterior wall surface into which dynamic seal  58  is seated for sealing against the wall of chamber  51  in housing  52  ( FIG. 3 ). Similarly, a circumferential groove  67  is provided around the inner wall surface into which dynamic seal  57  is seated for sealing against the outer wall section of tubular member  12  ( FIG. 3 ). Body lock ring  54  includes a section having ratchet tooth profile  56 . In particular, and as best seen in  FIG. 3 , a typical ratchet tooth profile is similar to a buttress thread; one side of each tooth is perpendicular to the longitudinal axis  24  (as in a square tooth), while the obverse side of each tooth is sloped (as in a ‘V’ tooth). 
     Preferably, body lock ring  54  includes a number of slots formed therein to provide a limited resilience to allow body lock ring to elastically deform in a radial direction. As the ‘V’ sides of ratchet teeth  56  slide against the ‘V’ sides of ratchet teeth  53  ( FIG. 3 ), an outward radial force is created that temporarily deforms body lock ring  54 , thereby allowing the teeth to pass each other. However, when the square sides of ratchet teeth  56  engage the square sides of ratchet teeth  53 , no radial force is exerted on body lock ring  54 , and no axial motion is permitted. In this manner, body lock ring  54  is capable only of unidirectional motion with respect to portion  31  of sleeve  30  ( FIG. 3 ). 
     As illustrated, four slots are provided. Two partial slots  70 A,  70 B are formed halfway through body lock ring  54  at first end  55 , one partial slot  71  is formed halfway through body lock ring  54  at second end  59 , and one slot  72  is a full slot formed through the entire ring. However, other numbers and combinations of slots and half slots, or other materials, mechanisms, or techniques may be used as appropriate to obtain a ratcheting effect or unidirectional motion. Additionally, body lock ring  54  is described and illustrated as having a ratchet tooth profile  56  on its inner diameter to engage a ratchet tooth profile  53  on the outer diameter of sleeve portion  31 , a body lock ring with ratchet teeth on its outer diameter may be used as appropriate. 
     Returning back to  FIG. 3 , body lock ring  54  is nearly fully engaged with sleeve  30  due to the pressurization of the interior  18  of tubular member  12 . Now referring to  FIG. 5 , the interior  18  is depressurized. Resilient member  62  forces body lock ring  54  back into its original position, and because of the unidirectional ratchet threads  56 ,  53 , sleeve  30  is axially moved along with body lock ring  54  into an open position. Openings  32  are now aligned with apertures  14  to allow well production. 
     Although screen assembly  10  is described herein predominately with respect to a single unit, multiple screen assemblies may be used within a single tubing string. Pressurizing the tubing string works to actuate every body lock ring in the string, and subsequently releasing the internal pressure opens every screen in the completion at once. 
     The Abstract of the disclosure is solely for providing the United States Patent and Trademark Office and the public at large with a way by which to determine quickly from a cursory reading the nature and gist of technical disclosure, and it represents solely a preferred embodiment and is not indicative of the nature of the invention as a whole. The design of screen assembly  10  as described herein also allows the screen gauge to be remotely adjusted by cycling or adjusting the internal pressure so as to clear the screen or increase production, for example. 
     While various embodiments have been illustrated in detail, the disclosure is not limited to the embodiments shown. It is apparent that modifications and adaptations of the above embodiments may occur to those skilled in the art. Such modifications and adaptations are in the spirit and scope of the disclosure.