Patent Publication Number: US-8967241-B2

Title: Junk basket with self clean assembly and methods of using same

Description:
PRIORITY INFORMATION 
     This application is a DIVISIONAL of U.S. patent application Ser. No. 13/342,260, filed on Jan. 3, 2012, and claims the benefit of priority from the aforementioned application. 
    
    
     BACKGROUND 
     1. Field of Invention 
     The invention is directed to a downhole clean-up tool for use in oil and gas wells, and in particular, to a downhole clean-up tool that is capable of self-cleaning debris out of the flow path so that the tool can continue to operate for a longer period of time. 
     2. Description of Art 
     Downhole tools for clean-up of debris in a wellbore are generally known and are referred to as “junk baskets.” In general, the junk baskets have a screen or other structure that catches debris within the tool as fluid flows through the tool. This occurs because the fluid carrying the debris flows through the tool such that at a point in the flow path, the speed of the fluid flowing through the tool decreases such that the junk or debris falls out of the flow path and into a basket or screen. 
     SUMMARY OF INVENTION 
     Broadly, downhole tools for clean-up of debris within a well comprise a screen member and a wiper member in sliding engagement with each other to wipe away debris that might be caught in the screen member. The wiper member can be disposed in sliding engagement with the downstream or outer wall surface of the screen member, or in sliding engagement with the upstream or inner wall surface of the screen member. The wiper member also includes one or more window to allow periodic blocking of fluid flow through the screen member during operation of the downhole tools. 
     In certain specific embodiments, the wiper member includes one or more directional flow ports through one end of the wiper member to facilitate rotation of the wiper member relative to the screen member. In other specific embodiments, the screen member includes one or more directional flow ports through one end of the screen member to facilitate rotation of the screen member relative to the wiper member. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a partial cross-sectional view of a specific embodiment of a downhole tool disclosed herein. 
         FIG. 2  is a perspective view of an embodiment of a screen member and an embodiment of a wiper member of the downhole tool shown in  FIG. 1 . 
         FIG. 3  is a perspective view of an embodiment of the wiper member shown in  FIGS. 1 and 2 . 
         FIG. 4  is partial cross-sectional view of an embodiment of the screen member and the wiper member shown in  FIGS. 1 and 2  showing a flow path through the screen member and the wiper member. 
         FIG. 5  is partial cross-sectional view of another embodiment of a screen member and wiper member of a downhole tool disclosed herein. 
         FIG. 6  is a cross-sectional view of another embodiment of a downhole tool disclosed herein. 
         FIG. 7  is a cross-sectional view of an additional embodiment of a downhole tool disclosed herein. 
         FIG. 8  is a perspective view of an additional embodiment of a screen member of the downhole tool shown in  FIG. 7 . 
     
    
    
     While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF INVENTION 
     Referring now to  FIGS. 1-4 , in one particular embodiment, downhole tool  30  comprises tubular member  31  having outer wall surface  32 , and inner wall surface  33  defining longitudinal bore  34 . Disposed within bore  34  is screen member  40  and wiper member  50 . In the particular embodiment of  FIGS. 1-4 , screen member  40  is secured within bore  34  by flange  35  formed by inner wall surface  33 . It is to be understood, however, that flange  35  is not required to secure screen member  40  within bore  34 . Any other device or method known in the art can be used to secure screen member  40  within bore  34 . 
     Screen member  40  comprises upper end  41 , lower end  42 , upstream or outer wall surface  43 , downstream or inner wall surface  44  defining screen bore  45  ( FIG. 4 ), and a plurality of apertures  48  ( FIGS. 2 ,  4 , and  5 ). Although screen member  40  is shown has having a plurality of apertures  48 , it is to be understood that screen member  40  can have as few as one aperture  48 . As shown in  FIG. 4 , in this particular embodiment, lower end  42  is closed and upper end  41  is opened to receive wiper member  50 . 
     Wiper member  50  comprises upper end  51 , lower end  52 , upstream or outer wall surface  53 , downstream or inner wall surface  54  defining wiper bore  55  ( FIGS. 3 ,  4 , and  5 ), and two windows  58  ( FIG. 3 ). Outer wall surface  53 , inner wall surface  54 , and windows  58  define wiper blades  57 . Wiper blades  57  can be straight (as shown in  FIG. 3 ), curved (not shown), or any other layout or design desired or necessary to facilitate operation of downhole tool  30 . In the embodiment of  FIGS. 1-4 , upper end  51  is closed and lower end  52  is opened. Disposed at upper end  51  are directional ports  59 . Directional ports  59  facilitate rotation of wiper member  50  so that outer wall surface  53  of wiper member  50  is in sliding engagement with inner wall surface  44  of screen member  40 . Directional ports  59  can be in any size, shape, or pattern as long as when fluid is flowing through directional ports  59 , wiper member  50  rotates. 
     The term “downstream wall surface” as used herein means the wall surface after the fluid has passed through the screen member or the wiper member and the term “upstream wall surface” as used herein means the wall surface before the fluid has passed through the screen member or the wiper member. 
     Screen member  40  and wiper member  50  can be formed out of any desired or necessary material to facilitate catching and wiping away debris. In one embodiment, both screen member  40  and wiper member  50  are formed of metal such as steel. In another embodiment, wiper member  50  is formed of a non-metallic material to reduce weight. 
     Referring now to  FIG. 5 , in one specific embodiment of downhole tool  30  described above with respect to  FIGS. 1-4 , inner wall surface  54  comprises a plurality of bristles or brush members  70 . As discussed in greater detail below, brush member(s)  70  facilitate(s) removal of debris disposed along inner wall surface  43  of screen member  40 . 
     Although brush members  70  are shown disposed uniformly over the entire inner wall surface  54 , it is to be understood that brush members  70  can be distributed along inner wall surface  54  in any arrangement and can be limited to as few as one brush member  70 . 
     In operation, downhole tool  30  is included as part of a tubing or work string that is then disposed within a wellbore. Conventional fluid circulation down through the work string is utilized to perform a reverse circulating action downhole to collect debris such as metal cuttings and other junk. The circulation of fluid through the work string flows debris upward through downhole tool  30 . The fluid passes through apertures  48  into bore  45  of screen member  40 . Apertures  48  allow the fluid to pass through screen member  40  (as indicated by arrows  63  ( FIGS. 4 and 5 ) causing debris to be captured along outer wall surface  43  of screen member  40 . In some instances, the debris will fall downward into a basket (not shown) disposed below screen member  40  due to the force of gravity being greater than the force of the fluid flowing upward. This occurs because, even though the fluid circulation rate needs to be increased to pick up large size debris, the pressure drop across screen member  40  caused by the fluid flow rate causes smaller sized debris to stick to outer wall surface  43  of screen member  40  causing circulation to become restricted such that the larger debris falls downward. To prevent the likelihood that all circulation is cut-off by the smaller debris, wiper member  50  is rotated within screen bore  45  restricting fluid flow through one or more of apertures  48 . As wiper blade(s)  57  rotate, a portion of apertures  48  are periodically no longer in fluid communication with screen bore  45  causing the pressure drop across apertures  48  to lessen or disappear which, in turns, causes the debris to fall-off of outer wall surface  43 . As wiper member  40  is rotated, fluid flow is reestablished through the previously restricted apertures  48  and continued downhole clean-up can proceed without further intervention. In embodiments in which brush members  70  are present, brush members  70  facilitate removal of debris along outer wall surface  43  such as by temporarily being disposed through apertures  48  to push debris out of apertures  48 . 
     As shown in the embodiment of  FIGS. 1-5 , fluid flowing through apertures  48  and through windows  58  enters wiper bore  55  and then flows out of directional ports  59  as indicated by arrow  61  ( FIG. 2 ). Due to the orientation of directional ports  59 , wiper member  40  is rotated as indicated by arrow  60  ( FIGS. 2 ,  4 , and  5 ) within screen bore  45  such that outer wall surface  53  of wiper member  50  is in sliding engagement with inner wall surface  44  of screen member  40 . 
     Referring now to  FIG. 6 , in another specific embodiment, downhole tool  130  comprises tubular member  131  having outer wall surface  132 , inner wall surface  133  defining longitudinal bore  134 . Disposed within bore  134  is screen member  140  and wiper member  150 . In the particular embodiment of  FIG. 6 , screen member  140  is secured within bore  134  by flange  136  formed by inner wall surface  133 . It is to be understood, however, that flange  136  is not required to secure screen member  140  within bore  134 . Any other device or method known in the art can be used to secure screen member  140  within bore  134 . 
     Screen member  140  comprises upper end  141 , lower end  142 , outer wall surface  143 , inner wall surface  144  defining screen bore  145 , and a plurality of apertures  148 . Although screen member  140  is shown has having a plurality of apertures  148 , it is to be understood that screen member  140  can have as few as one aperture  148 . Upper end  141  and lower end  142  are closed. 
     Wiper member  150  comprises upper end  151 , lower end  152 , outer wall surface  153 , inner wall surface  154  defining the wiper bore, and windows  158 . Outer wall surface  153 , inner wall surface  154 , and windows  158  define wiper blades (not shown) in the same manner as described above with respect to wiper member  50 . Upper end  151  and lower end  152  are opened so screen member  140  can extend above and below upper end  151  and lower end  152 , respectively. Disposed at upper end  151  are directional ports  159 . Directional ports  159  facilitate rotation of wiper member  150  so that outer wall surface  143  of screen member  140  is in sliding engagement with inner wall surface  154  of wiper member  150 . Directional ports  159  can be in any size, shape, or pattern as long as when fluid is flowing through directional ports  159 , wiper member  150  rotates. 
     In the embodiment of  FIG. 6 , wiper member  150  is operatively associated with flange  135  formed by inner wall surface  133 . Bearing  180  facilitates rotation of wiper member  150  along the upper surface of flange  135  in the direction of arrow  160 . 
     Chamber  138  is defined by flanges  135 ,  136  to receive fluid flowing from directional ports  159 . Passages  137  permit fluid to flow from chamber  138  through flange  136  and into bore  134  above screen member  140  and wiper member  150 . 
     In operation, fluid flows upward in the same manner as described above with respect to the embodiment of  FIGS. 1-5 . In so doing, the fluid flows in the direction of the arrows shown in  FIG. 6 , namely, through windows  158 , through apertures  148  disposed below flange  135 , into bore  145 , out of apertures  148  disposed above flange  135 , through directional ports  159 , into chamber  138 , through passages  137 , and into bore  134  above screen member  140  and wiper member  150 . As fluid flows through this path, wiper member  150  rotates in the direction of arrow  160  causing periodic pressure drop across apertures  148  so that debris is cleaned from outer wall surface  143  of screen member  140  facilitating continued downhole clean-up without further intervention. 
     Referring now to  FIGS. 7-8 , in an additional embodiment, downhole tool  230  comprises tubular member  231  having outer wall surface  232 , inner wall surface  233  defining longitudinal bore  234 . Disposed within bore  234  is screen member  240  and wiper member  250 . In the particular embodiment of  FIGS. 7-8 , wiper member  250  is secured within bore  234  by flange  235  formed by inner wall surface  233 . It is to be understood, however, that flange  235  is not required to secure wiper member  250  within bore  134 . Any other device or method known in the art can be used to secure wiper member  250  within bore  234 . 
     Wiper member  250  comprises upper end  251 , lower end  252 , outer wall surface  253 , inner wall surface  254  defining the wiper bore, and windows  258 . Outer wall surface  253 , inner wall surface  254 , and windows  258  define wiper blades (not shown) in the same manner as described above with respect to wiper member  50 . Upper end  251  and lower end  252  are opened so screen member  240  can extend above and below upper end  251  and lower end  252 , respectively. 
     As shown in  FIGS. 7-8 , screen member  240  comprises upper end  241 , lower end  242 , outer wall surface  243 , inner wall surface  244  ( FIG. 7 ) defining screen bore  245  ( FIG. 7 ), and a plurality of apertures  248 . Although screen member  240  is shown has having a plurality of apertures  248 , it is to be understood that screen member  240  can have as few as one aperture  248 . Upper end  241  and lower end  242  are closed. Disposed at upper end  241  are directional ports  259 . Directional ports  259  facilitate rotation of screen member  240  so that outer wall surface  243  of screen member  240  is in sliding engagement with inner wall surface  254  of wiper member  250 . Directional ports  259  can be in any size, shape, or pattern as long as when fluid is flowing through directional ports  259 , screen member  240  rotates. 
     In the embodiment of  FIGS. 7-8 , screen member  240  is operatively associated with flange  235  formed by inner wall surface  233 . Bearing  280  facilitates rotation of screen member  240  along the upper surface of flange  235  in the direction of arrow  260 . 
     In operation, fluid flows upward in the same manner as described above with respect to the embodiment of  FIGS. 1-5 . In so doing, the fluid flows in the direction of the arrows shown in  FIG. 7 , namely, through windows  258 , through apertures  248 , into bore  245 , through directional ports  259 , and into bore  134  above screen member  240  and wiper member  250 . As fluid flows through this path, screen member  240  rotates in the direction of arrow  260  causing periodic pressure drop across apertures  248  so that debris is cleaned from outer wall surface  243  of screen member  240  facilitating continued downhole clean-up without further intervention. 
     It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. For example, in embodiments in which either the screen member or the wiper member is stationary, any device or method known in the art to maintain the screen member or wiper member stationary can be used. In addition, the wiper member can have as few as one window. Alternatively, the wiper member can have three or more windows. Moreover, the apertures in screen member can have any arrangement, size and dimensions as desired or necessary to restrict flow of debris through screen and to allow debris stuck on the screen member to be removed by the wiper member. Further, brush members can be included in any of the embodiments of  FIGS. 1-8 . Additionally, the directional ports in the embodiment of  FIGS. 1-6  can be absent and instead, rotation of the wiper member can be caused by fluid flowing through one or more helical grooves disposed along the upstream or outer wall surface of the wiper member. Alternatively, rotation of wiper member can be caused by fluid flowing against one or more tilted or angled blades disposed along the upstream or outer wall surface of the wiper member. 
     In addition, screen member can have a flat geometric shape with the wiper member in sliding engagement with the downstream wall surface of the screen member such that the downstream wall surface is substantially horizontal to a longitudinal axis of the downhole tool. In this embodiment, the wiper can comprise a shaft with an upper end that is operatively associated with a bearing disposed on a flange member and the blades are shape to cause rotation as fluid flows through the aperture(s) of the screen member. The flange member includes one or more passages similar to passages  137  as shown in  FIG. 6 . Alternatively, the wiper member can be held stationary and the screen member can be rotatable on bearings disposed on the inner wall surface of the tubular member. To facilitate such rotation, the screen member can have one or more fins or other structures, such as the ones identified above, that cause screen to rotate as fluid flows through the aperture(s). Accordingly, the invention is therefore to be limited only by the scope of the appended claims.