Abstract:
A blanking plug device, system and method of use, wherein the plug device has an anchoring portion for securing the blanking plug device within a tubing string or other well conduit. In preferred embodiments, the anchoring portion comprises a locking device such as the Extreme SUR-SET® locking system. However, other anchoring mechanisms may be utilized as well. The blanking plug device has a lower plug portion that incorporates a screening section. The screening section permits flow of fluid through the sidewall of the plug portion while substantially preventing the passage of solid particles.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present application claims the priority of U.S. Provisional patent application serial No. 60/463,163 filed Apr. 16, 2003.  
           [0002]    1. Field of the Invention  
           [0003]    The invention relates generally to downhole locking devices and blanking plugs. In specific aspects, the invention relates to devices and methods for sand control in association with these devices.  
           [0004]    2. Description of the Related Art  
           [0005]    Locking devices, or locks, are used to anchor a well tool at a particular location within a well conduit, such as a tubing string. A locking device is described in U.S. Pat. No. 4,510,995 entitled “Downhole Locking Apparatus” which was issued to Krause, Jr. et al. and is owned by the assignee of the present application. That patent is incorporated herein by reference. A locking device of this type is also available commercially as the Extreme SUR-SET® locking system sold by Baker Oil Tools, 6023 Navigation Blvd., Houston, Tex. 77253. This locking device has a set of radially expandable locking dogs that seat within a complimentary nipple or profile in the tubing string. The lock also incorporates a no-go shoulder to help ensure proper positioning in the tubing string. The lock is run into the tubing string using a running tool, which also sets the lock by expanding the locking dogs into the matching nipple. The running tool is then removed. When it is desired to remove the lock, a retrieval tool is run into the tubing string, engages the lock and retracts the locking dogs. The retrieval tool and lock may then be removed from the wellbore.  
           [0006]    Safety valves and check valves are typically anchored with a lock. Alternatively, a lock may serve as a blanking plug to establish a fluid seal within the tubing string. One example is the Extreme SUR-SET® Model H blanking plug available from Baker Oil Tools, 6023 Navigation Blvd., Houston, Tex. 77253. When in place, the blanking plug blanks off all pressure from above or below the lock. Blanking plugs are useful for pressure testing the tubing string or to abandon certain zones within a well.  
           [0007]    Certain blanking plugs use a removable prong that is inserted into the plug to equalize the pressure across the plug and to complete the fluid seal. A pressure equalization port is disposed through the housing of the plug. After setting the plug portion and prior to installation of the prong, fluid containing sand or other solid particles may enter this port and cause clogging of the interior. As a result, it may be difficult to insert or secure the prong within the plug portion. The present invention addresses the problems of the prior art.  
         SUMMARY OF THE INVENTION  
         [0008]    The invention provides an improved blanking plug device having an anchoring portion for securing the blanking plug device within a tubing string or other well conduit. In preferred embodiments, the anchoring portion comprises a locking device such as the Extreme SUR-SET® locking system. However, other anchoring mechanisms may be utilized as well. The blanking plug device has a lower plug portion that incorporates a screening section. The screening section permits flow of fluid through the sidewall of the plug portion while substantially preventing the passage of solid particles. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The advantages and further aspects of the invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawing and wherein:  
         [0010]    [0010]FIG. 1 is a side, cross-sectional view of an exemplary locking device configured for use as a blanking plug.  
         [0011]    [0011]FIG. 2 is an enlarged view of a lower portion of the blanking plug shown in FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]    [0012]FIG. 1 depicts an exemplary blanking plug device  10  that has been constructed in accordance with the present invention. The blanking plug device  10  is adapted to be run into a production tubing string (not shown) or other well conduit on slickline or wireline. As such operations are well known in the art, they are not described in any detail here. The blanking plug device  10  depicted has two separate components: a plug  12  and a blanking member, specifically prong,  14 , which is shown removably disposed within the plug  10 . In operation, the plug  12  is run into the tubing string first and then the prong  14  is run into the tubing string and seated inside the plug  12 . The plug  12  has an upper anchoring lock portion  16 , the upper end of which is shown at  18 . In preferred embodiments, the lock portion  16  is a locking device of the type described in U.S. Pat. No. 4,510,995. Preferably, the lock portion  16  comprises an Extreme SUR-SET® locking system. Because the structure and operation of this type of lock portion  16  is well known, it will only be described briefly herein. While in preferred embodiments of the present invention the lock portion  16  is a locking mechanism of the type described in U.S. Pat. No. 4,510,995 or an Extreme SUR-SET® locking system, the invention is not, in fact, limited only to these devices. Rather, the invention has application as well for other types of anchoring mechanisms, including those that, for example, do not require a complimentary profile or nipple within the tubing string and those that might anchor within a tubing string using slips, packers, or other means known in the art for securing a tool within a conduit.  
         [0013]    The exemplary lock portion  16  includes a generally cylindrical outer housing  20  and an inner mandrel  22  that is axially moveable with respect to the outer housing in order to accomplish setting and unsetting of the lock portion  16  within a section of tubing. The outer housing  20  features a set of annular seals  24  above its lower end  26 . A plurality of radially expandable locking dogs  28  are spaced about the circumference of the lock portion  16  and are shaped and sized to selectively reside within a complimentary nipple or profile (not shown) within a tubing string section. The inner mandrel  22  of the lock portion  16  defines a central axial bore  30 .  
         [0014]    A plug section  32  is secured to the lower end  26  of the outer housing  20  via threaded connection  34 . FIG. 2 provides an enlarged view of the plug section  32 . The plug section  32  is a tubular body  36  that terminates in a rounded nose cone  38 . An axial blind bore  40  is defined within the body  36  and, when the plug section  32  is secured to the outer housing  20 , the blind bore  40  is aligned with the central axial bore  30 . One or more pressure equalization ports  42  (one shown) are disposed radially through the tubular body  36 . As FIG. 2 depicts, the outer radial surface of the tubular body  36  has a radially reduced portion, or groove,  44 . The equalization port(s)  42  is (are) disposed through the body  36  within this groove  44 . A screen  46  surrounds the tubular body  36 , residing within the groove  44 . The screen  44  provides a mesh for screening out of sand and other solid particles and prevents their entry into the equalization port(s)  42 . While screen  44  preferably comprises a sand screen, of a type known in the art, other suitable filtering media may be used as well. Further, while the screen  44  is shown as being located radially outside of the body  36 , it might as easily be located at any point within the port  42  or even at the radially interior end of the port  42 .  
         [0015]    The prong  14  includes an upper enlarged portion  47  and a reduced diameter prong portion  48 . The prong portion  48  is shaped and sized to reside within the axial bore  30  and blind bore  40  when the prong  14  is inserted axially into the plug  12 . The enlarged portion  47  will be seated atop the upper end  18  of the plug  12  when the prong  14  is fully inserted. The prong portion  48  carries a pair of annular fluid seals  50 ,  52  proximate its lower end  54 . When the prong  14  is fully inserted into the plug  12 , the enlarged portion  47  of the prong  14  seats against the upper end  18  to provide a no-go shoulder stop that prevents further downward movement of the prong  14  within the plug  12 . At this point, the seals  50 ,  52  are positioned on either side of the equalization port(s)  42  of the plug section  32 . It is also noted that the prong portion  48  defines a central axial fluid bore  56  and that a pressure port  58  is disposed proximate the lower end of the prong portion  48  to enable fluid communication between the exterior of the prong portion  48  and the bore  56 .  
         [0016]    In operation, the plug  12  is run into a tubing string by a running tool (not shown), and the running tool is used to radially expand the locking dogs  28  into a mating profile or nipple in the tubing string in a manner that is known in the art. The running tool is withdrawn from the tubing string. At this point, fluid within the tubing string is capable of entering the axial bore  30  and blind bore  40  via the equalization port(s)  42 . The screen  46  prevents sand and other solids from entering the equalization port  42 .  
         [0017]    The prong  14  is then run into the tubing string on a separate running tool (not shown) and inserted into the plug  12 , again in a manner well known in the art. As the prong portion  48  enters the axial bore  30 , fluid within the axial bore  30  and blind bore  40  will enter the pressure port  58  and the axial bore  56  of the prong  14 , thereby equalizing pressure across the plug  12 . As the prong  14  becomes fully seated within the plug  12 , the annular seal  52  will move below the equalization port  42 , thereby preventing further transmission of fluid from the equalization port  42  into the pressure port  58 . The prong  14  is then locked into the plug  12 , in a manner known in the art, to blank off pressure across the blanking plug device  10 .  
         [0018]    The foregoing description is directed to particular embodiments of the present invention for the purpose of illustration and explanation. It will be apparent, however, to one skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope and the spirit of the invention.