Abstract:
An improved method and apparatus for catching and holding a ball, plug or dart during oil and gas well operations (e.g., cementing operations) employs a specially configured tool body that accepts a ball or a plug or a dart that flows downwardly into the tool body but disallows escape or discharge of the ball, plug or dart upwardly. The tool body has first and second flow channels or passages, one being generally axially aligned with the tool body. The other flow channel or passage is a second channel or passage that enables fluid flow around a cavity that contains one or more captive plugs (or ball or dart(s)).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Priority of U.S. Provisional Patent Application Ser. No. 60/948,057, filed Jul. 5, 2007, incorporated herein by reference, is hereby claimed. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable 
       REFERENCE TO A “MICROFICHE APPENDIX” 
       [0003]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    The present invention relates to a method and apparatus that is of particular utility in cementing operations associated with oil and gas well exploration and production. More specifically the present invention provides an improvement to cementing operations and related operations employing a plug or ball dropping head. 
         [0006]    2. General Background of the Invention 
         [0007]    Patents have issued that relate generally to the concept of using a plug, dart or a ball that is dispensed or dropped into the well or “down hole” during oil and gas well drilling and production operations, especially when conducting cementing operations. The following possibly relevant patents are incorporated herein by reference. The patents are listed numerically. The order of such listing does not have any significance. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 
               
               
                   
               
               
                 U.S. PAT. NO. 
                 TITLE 
                 ISSUE DATE 
               
               
                   
               
             
             
               
                 3,828,852 
                 Apparatus for Cementing Well Bore 
                 August 1974 
               
               
                   
                 Casing 
               
               
                 4,427,065 
                 Cementing Plug Container and 
                 January 1984 
               
               
                   
                 Method of Use Thereof 
               
               
                 4,624,312 
                 Remote Cementing Plug Launching 
                 November 1986 
               
               
                   
                 System 
               
               
                 4,671,353 
                 Apparatus for Releasing a 
                 June 1987 
               
               
                   
                 Cementing Plug 
               
               
                 4,722,389 
                 Well Bore Servicing Arrangement 
                 February 1988 
               
               
                 4,782,894 
                 Cementing Plug Container with 
                 November 1988 
               
               
                   
                 Remote Control System 
               
               
                 4,854,383 
                 Manifold Arrangement for use with a 
                 August 1989 
               
               
                   
                 Top Drive Power Unit 
               
               
                 4,995,457 
                 Lift-Through Head and Swivel 
                 February 1991 
               
               
                 5,095,988 
                 Plug Injection Method and 
                 March 1992 
               
               
                   
                 Apparatus 
               
               
                 5,236,035 
                 Swivel Cementing Head with 
                 August 1993 
               
               
                   
                 Manifold Assembly 
               
               
                 5,293,933 
                 Swivel Cementing Head with 
                 March 1994 
               
               
                   
                 Manifold Assembly Having Remove 
               
               
                   
                 Control Valves and Plug Release 
               
               
                   
                 Plungers 
               
               
                 5,435,390 
                 Remote Control for a Plug-Dropping 
                 July 1995 
               
               
                   
                 Head 
               
               
                 5,758,726 
                 Ball Drop Head With Rotating Rings 
                 June 1998 
               
               
                 5,833,002 
                 Remote Control Plug-Dropping Head 
                 November 1998 
               
               
                 5,856,790 
                 Remote Control for a Plug-Dropping 
                 January 1999 
               
               
                   
                 Head 
               
               
                 5,960,881 
                 Downhole Surge Pressure Reduction 
                 October 1999 
               
               
                   
                 System and Method of Use 
               
               
                 6,142,226 
                 Hydraulic Setting Tool 
                 November 2000 
               
               
                 6,182,752 
                 Multi-Port Cementing Head 
                 February 2001 
               
               
                 6,390,200 
                 Drop Ball Sub and System of Use 
                 May 2002 
               
               
                 6,575,238 
                 Ball and Plug Dropping Head 
                 June 2003 
               
               
                   
               
             
          
         
       
     
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention provides an improved method and apparatus for use in cementing and like operations, employing an apparatus that catches and retains a plug or ball dropping head, preventing inadvertent discharge or escape of the plug. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]    For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: 
           [0010]      FIGS. 1A-1B  are sectional elevation views of the preferred embodiment of the apparatus of the present invention and wherein line A-A are match lines; 
           [0011]      FIG. 2  is a sectional, elevation view of the preferred embodiment of the apparatus of the present invention and showing the method of the present invention; 
           [0012]      FIG. 3  is a sectional, elevation view of the preferred embodiment of the apparatus of the present invention and showing the method of the present invention; 
           [0013]      FIG. 4  is a sectional, elevation view of the preferred embodiment of the apparatus of the present invention and showing the method of the present invention; 
           [0014]      FIG. 5  is a sectional, elevation view of the preferred embodiment of the apparatus of the present invention and showing the method of the present invention; and 
           [0015]      FIG. 6  is a sectional view of the preferred embodiment of the apparatus of the present invention and showing the method of the present invention wherein lines B-B are match lines. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIGS. 1-6  show generally the preferred embodiment of the apparatus of the present invention designated generally by the numeral  10 . The downhole tool  10  of the present invention is used to catch and retain one or more plugs, balls or darts  11  that have been used as part of a cementing operation or other downhole oil well operation. The present invention could be applied to any operation that requires separation of fluid in an oil and gas well environment. Any severely deviated hole where the top and bottom of the cement needs to be defined accurately would typically require plugs. 
         [0017]    The downhole tool  10  of the present invention provides a tool body  20  having an upper end portion  21  and a lower end portion  22 . A main flow bore  23  or first channel extends substantially the length of tool body  20 . The bore or channel  23  can be open-ended as shown in  FIG. 1 . Tool body  20  is typically mounted in a well string or work string  12  or pipe string, being attached to joints of pipe  13 ,  14  and lowered into the well bore  15 . Well bore  15  can be lined with casing  16  or other known liner. Joint  13  of string  12  connects to tool body  20  at upper end portion  21 . Joint  14  of string  12  connects to tool body  20  at lower end portion  22 . The tool body  20  thus provides at its upper end portion  21  an internally threaded section  24  for enabling attachment to the joint of pipe  12  that is above tool body  20 . Similarly, the lower end portion  22  of tool body  20  provides an externally threaded section  25  for enabling it to be attached to the joint of pipe  14  that extends below tool body  20 . 
         [0018]    Tool body  20  can be a multi section tool body as shown in  FIGS. 1A-1B . The tool body  20  thus can provide an upper tool body section  26 , a lower tool body section  27  and a central tool body section  28 . These tool body sections  26 ,  27 ,  28  can be assembled together using threaded connections for example. In  FIGS. 1A-1B , a threaded connection  29  can be used for joining upper tool body section  26  to central tool body section  28 . Similarly, a threaded connection  30  can be used for joining lower tool body section  27  to central tool body section  28 . 
         [0019]    Upper tool body section  26  provides a restriction or a smaller diameter bore section  31  as shown. Below the restriction or smaller diameter bore section  31  is provided a larger diameter bore section  32  that is adapted to hold and retain one or more plugs, balls, or darts  11  as shown. Thus, the internal diameter of larger diameter section  32  can be about the same as the external diameter of the ball, plug or dart  11  to be contained. 
         [0020]    A tapered surface  33  is provided on upper tool body section  26  immediately below internally threaded section  24 . A generally cylindrically shaped surface  34  is provided below tapered surface  33 . Another tapered surface  35  is provided below the generally cylindrically shaped surface  34 . 
         [0021]    Sleeve  36  extends downwardly from upper tool body section  26  as shown in  FIGS. 1A-1B . Sleeve  36  can be attached to upper tool body section  26  using a threaded connection  37 . The sleeve  36  can be a generally cylindrically shaped sleeve that is concentrically placed inside of the central tool body section  28  as shown in  FIGS. 1A-1B . 
         [0022]    Sleeve  36  provides an upper enlarged portion  46  having one or more flow ports  43 . Sleeve  36  also provides a lower enlarged portion  47 . Check valve  40  is attached to the tool body  20  and can be attached to the lower enlarged portion  47  of sleeve  36 . An O-ring  39  can be provided as a seal in between sleeve  36  and check valve  40 . Check valve  40  provides a valving member  41 . Valving member  41  only allows flow in the direction of arrow  42 . Check valve  40  can be a commercially available check valve such as is sold under the trademark Conbraco, such as a Series 61 stainless steel ball-cone type check valve. 
         [0023]    Flow ports  44  extend between second channel  50  and first channel  23  at a position below larger diameter section  32  of first channel  23  and preferably below check valve  40 . Thus, fluid flow can circumvent the balls, plugs or darts  11  that are contained within the larger diameter section  32  or first channel  23 . Flow through second channel  50  thus begins in first channel  23  at a position near restriction  31 . Flow then circumvents the plug, ball, dart  11  by passing from first channel  23  via ports  43  to second channel  50  and then downwardly in second channel  50  to ports  54  which are in the lower end portion  22  of tool body  20  (see  FIGS. 3-5 ). From ports  44 , flow again enters first channel  23  at a position that is next to tapered surface  45  and generally below lower enlarged portion or below check valve  40 . 
         [0024]    During use, one or more plugs, balls, darts  11  are used in a downhole oil well environment as part of a cementing operation. These plugs, balls, darts  11  are typically used to provide a well-defined front and rear to a volume of cement  17  that is pumped down hole as indicated schematically by arrows  18  in  FIGS. 2-5 . Thus, the first ball, dart or plug  11  can be put in front of the volume of cement  17  while a second plug, ball or dart  11  is placed above or at the rear of volume of cement  17 . When the ball, plug or dart  11  that is in front of the volume of cement reaches restriction  31 , it can be pumped through the restriction  31  by increasing pressure behind it, forcing it to deform and pass through the restriction  31  (see arrow  19  in  FIG. 2 ). Such plugs, balls, darts  11  are typically of a deformable material such as a rubber material, an elastomeric material, a polymeric material or the like. Once inside the larger diameter section  32  of bore  23 , the ball, plug or dart  11  has a memory and it regains its original shape (see  FIG. 3 ). 
         [0025]    From its position within enlarged diameter section  32  ( FIG. 3 ), only an increase of pressure from a position below the ball or dart or plug  11  can force it upwardly back through the restriction  31 . However, check valve  40  prevents such a rearward or upward flow of pressurized fluid. Because the ball, plug or dart  11  blocks the flow of cement downwardly in the main bore  23 , it circumvents the tool body  20  by traveling in the second channel  50 . Cement  17  is able to bypass section  32  by entering ports  43 , then channel  50 , and then ports  44  until it is below check valve  40  (see arrows  48 ,  FIGS. 3-4 ) and can exit the tool body  20  in the direction of arrows  49 . 
         [0026]    The volume of cement  17  can then be pumped to and below packer  51  via perforations  53  in casing  16  and into producing formation  52 , as indicated by arrows  54 . Packer  51  is commercially available and/or known in the art. 
         [0027]    The following is a list of parts and materials suitable for use in the present invention. 
         [0000]    
       
         
               
             
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
             
          
           
               
                 Part Number 
                 Description 
               
               
                   
               
               
                 10 
                 down hole tool 
               
               
                 11 
                 plug/ball/dart 
               
               
                 12 
                 well string/work string 
               
               
                 13 
                 joint of pipe 
               
               
                 14 
                 joint of pipe 
               
               
                 15 
                 well bore 
               
               
                 16 
                 casing 
               
               
                 17 
                 volume of cement 
               
               
                 18 
                 arrow 
               
               
                 19 
                 arrow 
               
               
                 20 
                 tool body 
               
               
                 21 
                 upper end portion 
               
               
                 22 
                 lower end portion 
               
               
                 23 
                 flow bore/first channel 
               
               
                 24 
                 internally threaded section 
               
               
                 25 
                 externally threaded section 
               
               
                 26 
                 upper tool body section 
               
               
                 27 
                 lower tool body section 
               
               
                 28 
                 central tool body section 
               
               
                 29 
                 threaded connection 
               
               
                 30 
                 threaded connection 
               
               
                 31 
                 restriction/smaller 
               
               
                   
                 diameter section 
               
               
                 32 
                 larger diameter section 
               
               
                 33 
                 tapered surface 
               
               
                 34 
                 cylindrically shaped surface 
               
               
                 35 
                 tapered surface 
               
               
                 36 
                 sleeve 
               
               
                 37 
                 threaded connection 
               
               
                 38 
                 tapered surface 
               
               
                 39 
                 O-ring 
               
               
                 40 
                 check valve 
               
               
                 41 
                 valving member 
               
               
                 42 
                 arrow 
               
               
                 43 
                 flow port 
               
               
                 44 
                 flow port 
               
               
                 45 
                 tapered surface 
               
               
                 46 
                 upper enlarged portion 
               
               
                 47 
                 lower enlarged portion 
               
               
                 48 
                 arrow 
               
               
                 49 
                 arrow 
               
               
                 50 
                 second channel 
               
               
                 51 
                 packer 
               
               
                 52 
                 formation 
               
               
                 53 
                 perforation 
               
               
                 54 
                 arrow 
               
               
                   
               
             
          
         
       
     
         [0028]    All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. 
         [0029]    The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.