Abstract:
An improved method and apparatus for removing metal cuttings from an oil well drilling mud stream provides a magnetic body or “ditch magnet” having end plates that extend radially and circumferentially from the magnetic body, the plates being positioned at end portions of the magnetic body. A third plate in the form of a wiper is used to dislodge metal cuttings and other metallic material from the magnetic body after the magnetic body has accumulated such metallic parts. One of the end plates can be removable to facilitate a complete scraping or wiping of the metallic parts from the metallic body by the wiper plate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 12/117,045, filed May 8, 2008 (issuing as U.S. Pat. No. 8,641,899 on Feb. 4, 2014), which claims benefit of U.S. Provisional Patent Application Ser. No. 60/916,977, filed May 9, 2007, each of which is hereby incorporated herein by reference and priority of which is claimed. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to magnets that are used to remove metal cuttings, metal shavings, metal parts, and like metallic material from a flow stream of oil well drilling mud. More particularly, the present invention relates to an improved method and apparatus for removing metal cuttings, metal shavings, metal parts and the like from an oil well drilling mud flow stream wherein a magnetized bar has first and second end portions, each carrying an end plate and wherein a non-magnetic wiper plate attaches to the magnetized bar in between the end plates, the wiper plate being slidable upon the magnetized bar between the end plates so that movement of the wiper plate from one end plate to the other end plate enables removal of the metal cuttings from the magnetized bar. 
     2. General Background of the Invention 
     Magnets have been used to remove metal from a flow stream of oil well drilling mud. Examples of commercially available magnets can be seen at the Stacey Oil Services, Ltd. website (www.staceyoil.com) and the Ceesan website (www.ceesan.net). Such magnets are also known in the industry as “ditch magnets”. Some patents have issued for ditch magnets. One such patent is U.S. Pat. No. 3,498,455. Other possibly relevant patents are listed chronologically in the following table. 
     
       
         
               
               
               
             
           
               
                 TABLE 
               
               
                   
               
               
                 PAT. NO. 
                 TITLE 
                 ISSUE DATE 
               
               
                   
               
             
             
               
                 2,792,115 
                 Magnetic Separator 
                 May 14, 1957 
               
               
                 3,498,455 
                 Ditch Magnet 
                 Mar. 30, 1970 
               
               
                 3,713,499 
                 Method and Apparatus for Treating 
                 Jan. 30, 1973 
               
               
                   
                 Drilling Mud 
               
               
                 4,030,558 
                 Wear Determination of Drilling 
                 Jun. 21, 1977 
               
               
                   
                 Bits 
               
               
                 5,944,195 
                 Method for Separation of Solids 
                 Aug. 31, 1999 
               
               
                   
                 from Drilling Fluids by Magnetic 
               
               
                   
                 Separation and Centrifugation 
               
               
                 6,354,386 
                 Apparatus for Retrieving Metal 
                 Mar. 12, 2002 
               
               
                   
                 Objects from a Wellbore 
               
               
                 2006/0016732 
                 High Gradient Magnetic Separator 
                 Jan. 26, 2006 
               
               
                 2007/0138103 
                 Magnetic Separation in Fluids 
                 Jun. 21, 2007 
               
               
                   
               
             
          
         
       
     
     Many of the metal parts that are collected by the ditch magnet are pieces that have been cut or shaved and are thus of irregular shape and can have jagged edges, sharp points, or the like. Safety is very important and meaningful in the oil and gas industry today. Cuttings that are collected by a ditch magnet can include sharp edged debris that could possibly cut the hand of a worker who handles the ditch magnet. 
     Cuttings that have been retrieved from a ditch magnet can provide information that is beneficial to oil and gas well operators. These collected cuttings may indicate casing wear during ordinary drilling operations, pipe wear, or any other factor which may be economically detrimental to the well or production. 
     Time is an important factor in oil and gas well drilling. The cost of drilling is rising. With drilling, rig rates as expensive as they are, a small part of time saved can equate to significant savings. Oil and gas well drilling rates can be as high as $125,000 to $600,000 per day. Thus, any procedure or apparatus that shortens the time for handling the ditch magnet and/or its debris can be a significant savings in money. 
     BRIEF SUMMARY OF THE INVENTION 
     The apparatus of the present invention provides an improved “ditch magnet” wherein a wiper flange of special configuration moves longitudinally along to wipe off metal cuttings that have become adhered to the magnet as it is immersed in a mass (e.g. flowing) of drilling mud. The present invention is safe to use because the wiper engages and wipes cuttings from the magnet. Because such cuttings can be sharp, pointed or jagged, injury to a worker can be avoided. 
     Because cuttings can be wiped into a container (such as the very shipping container used to carry the ditch magnet), they can be analyzed to determine their source (e.g. scrapings from casing, broken part, etc.) 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       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: 
         FIG. 1  is an elevation view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 2  is a side view of the preferred embodiment of the apparatus of the present invention taken along lines  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a perspective view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 4  is a fragmentary perspective view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 5  is a side view of the preferred embodiment of the apparatus of the present invention and showing part of the method of the present invention; 
         FIG. 6  is a side view of the preferred embodiment of the apparatus of the present invention and showing part of the method of the present invention; 
         FIG. 7  is a perspective view of the preferred embodiment of the apparatus of the present invention and showing part of the method of the present invention; and 
         FIG. 8  is a schematic diagram illustrating part of the method of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1-8  show the preferred embodiment of the apparatus of the present invention designated generally by the numeral  10  in  FIGS. 1-3  and  5 - 7 . In the drawings, the numeral  10  shows an apparatus for removing metal from drilling mud, which apparatus  10  can also be referred to as a “ditch magnet”. 
     The apparatus  10  is typically placed in a flow stream of drilling mud such as in the flow stream  63  shown in  FIG. 8 . Such a flow stream  63  can be any part of the structure of an oil and gas well drilling platform that utilizes drilling mud. One location that could be used as flow stream  63  for placement of the apparatus  10  is a vessel associated with oil and gas well drilling that is commonly referred to as “the ditch” or the “possum belly” section  60 . The apparatus  10  could also be placed in a pipeline or other flow stream that conveys drilling mud to shale shakers or other solids removal equipment that might be employed as part of the oil and gas well drilling mud system. 
     Over a period of time, a magnetic body  17  of apparatus  10  will attract metallic objects or material  51  that is flowing in the drilling mud stream (see arrows  15  in  FIG. 5 ). This metallic material can be cuttings, shavings, broken metal parts or the like. These unwanted metallic materials are generated as a part of oil and gas well drilling operation, fishing operation, milling operation, and/or completion operation. Such parts are at times lost in the well, or can be cut or shaved from casing or tubing as part of well drilling operations. 
     In  FIG. 8  there is shown schematically the various components of an oil and gas well drilling rig. The drilling rig includes a derrick  52  that supports a drill string  53 . At the lower end portion of the drill string  53  there is provided a drill bit  54 . The drill bit  54  cuts formation material which enters a drilling mud stream. 
     The drilling mud is pumped into the well via a discharge flow line  56  using a discharge or mud pump  55 . At the drill bit, the drilling mud collects drill cuttings and conveys them back to the surface. At the surface, a return flow line  57  carries the drilling mud and cuttings to a shale shaker  58 . 
     The shale shaker  58  removes solid material such as the rock cuttings that are cut by the drill bit  54 . Drilling mud then enters tank or vessel  59  that can have multiple sections such as a possum belly section  60  and a suction pit section  61 . Suction line  62  communicates between tank  59  and pump  55 . The apparatus  10  of the present invention can be placed at any number of locations in the schematic diagram of  FIGS. 5 and 8  such as for example in possum belly  60 , in suction pit  61  or in other locations where drilling mud flows or is contained. 
     A shipping container can be used to transport apparatus  10 . Such a container provides an interior having a lid or cover. The lid or cover can be attached to the shipping container using a hinge and latch. 
     Magnet assembly  16  provides an elongated magnet body  17  having a plurality of sides  11 ,  12 ,  13 ,  14 . Each of the sides  11 - 14  can be, for example, rectangular in shape. Magnet  17  provides end portions  19 ,  20 . Plate  21  is attached to magnet  17  at end portion  19 . This attachment can be for example a bolted connection, using a bolt  22  or other like fastener that connects to an internally threaded opening in the upper end portion  19  of magnet body  17 . Magnet body  17  can be an assembly that includes an outer hollow shell (e.g. stainless steel) and one or more magnets housing inside the shell. Magnet or magnets contained internally of such a hollow shell could extend between end portion  19  and reference line  49 . Thus no magnets would extend between reference line  49  and end portion  20 . 
     Plate  21  can provide spaced apart openings  23 ,  24  as shown in  FIG. 3 . Each opening  23 ,  24  can include a rectangular section  25  and a semi-circular section  26 . The semi-circular section  26  enables a rope, cable, chain, or other connector to form a connection with plate  21  at opening  23  or  24 . Such opening  23  or  24  can be employed when the ditch magnet  10  is to be suspended from a rope, cable, chain, hook, or the like. 
     Openings  23 ,  24  also enable a technician  50  to grip and lift ditch magnet  10  at plates  21 ,  27  when transporting the ditch magnet  10  from one location to another, or when removing it from its shipping container, or when placing it into a shipping container. 
     Plate  27  is a plate that is removable from magnet body  17  using a disconnectable, quick release or detachable connection. The plate  27  can be disconnectable from magnet  17  in a minimum of time so that its removal will facilitate the removal of any metal shavings, metal cuttings, metal parts, or other metallic objects  51  that are affixed to the outer surface or sides  18  of magnet body  17 . The plate  27  provides openings  28 ,  29 . Each of the openings  28 ,  29  has a generally rectangular section  30  and a semi-circular section  31  as with plate  21 . 
     Plate  27  provides a central opening  32 . Sleeve  33  is connected (for example, welded) to plate  27  at central opening  32 . Sleeve  33  provides sleeve bore  34  that is generally aligned with central opening  32  as shown. 
     In  FIGS. 4-7 , magnet body  17  provides end surface  35  fitted with pin  36 . Pin  36  provides a pin opening or channel  37  that is receptive of a locking pin  40 . Upon assembly of plate  27  to magnet body  17  at pin  36 , sleeve openings  38 ,  39  align with pin opening or channel  37 . In this fashion, locking pin  40  can pass through each of the openings or channels  37 ,  38 ,  39  to form a locking connection between the sleeve  33  and pin  36  as shown in  FIGS. 1-2 . Locking pin  40  can be attached to plate  27  using a ring  41 , tether  42  and fastener  43 . 
     Wiper plate  44  is preferably a non-metallic plate, being constructed for example of polymeric material, plastic material, or other like material. Wiper plate  44  is preferably non-metallic. Plate  44  provides openings  45 ,  46  as well as central opening  47 . The central opening  47  is of a size and shape that conforms to the transverse cross-section of magnet body  17  as shown in  FIGS. 2 ,  3  and  4 . 
       FIGS. 5-7  illustrate a removal of cuttings, metallic shavings, metal parts or like metal objects  51  from magnet  17  using wiper plate  44 . In  FIG. 7 , a technician  50  places ditch magnet  10  on a suitable surface or into a container. As shown in  FIG. 7 , a user  50  can grip and manipulate the assembly  16  of magnet  17  and wiper plate  27 . Openings  45 , 46  in  FIG. 7  enable user  50  to grip plate, the area next to the openings  45 ,  46  thus providing handles  64 . The technician  50  grips the handles  64  as shown in  FIG. 7  and moves wiper plate  44  in a direction indicated by arrow  48  from a beginning position next to plate  21  downwardly toward end  20 . 
     The technician removes locking pin  40  so that plate  27  can be separated from magnet  17 . As indicated by the reference line  49 , the part of magnet  17  in between reference line  49  and plate  27  is preferably not magnetized. When wiper plate  44  has pushed downwardly toward plate  27 , metal objects, cuttings, shavings, parts or the like that reach reference line  49  will no longer be subjected to a magnetic field and will fall from magnet body  17  to a floor or other surface or into a container. 
     Removed metallic material  51  can either be saved for later analysis and/or properly disposed of. 
     The following is a list of parts and materials suitable for use in the present invention. 
     
       
         
               
             
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
             
          
           
               
                 Part Number 
                 Description 
               
               
                   
               
               
                 10 
                 apparatus for removing metal from 
               
               
                   
                 drilling mud 
               
               
                 11 
                 side 
               
               
                 12 
                 side 
               
               
                 13 
                 side 
               
               
                 14 
                 side 
               
               
                 15 
                 arrow 
               
               
                 16 
                 magnet assembly 
               
               
                 17 
                 magnet body 
               
               
                 18 
                 side 
               
               
                 19 
                 end portion 
               
               
                 20 
                 end portion 
               
               
                 21 
                 plate 
               
               
                 22 
                 bolt/fastener 
               
               
                 23 
                 opening 
               
               
                 24 
                 opening 
               
               
                 25 
                 rectangular section 
               
               
                 26 
                 semi-circular section 
               
               
                 27 
                 plate 
               
               
                 28 
                 opening 
               
               
                 29 
                 opening 
               
               
                 30 
                 rectangular section 
               
               
                 31 
                 semi-circular section 
               
               
                 32 
                 central opening 
               
               
                 33 
                 sleeve 
               
               
                 34 
                 sleeve bore 
               
               
                 35 
                 end surface 
               
               
                 36 
                 pin 
               
               
                 37 
                 pin opening/channel 
               
               
                 38 
                 sleeve opening 
               
               
                 39 
                 sleeve opening 
               
               
                 40 
                 locking pin 
               
               
                 41 
                 ring 
               
               
                 42 
                 tether 
               
               
                 43 
                 fastener 
               
               
                 44 
                 wiper plate 
               
               
                 45 
                 opening 
               
               
                 46 
                 opening 
               
               
                 47 
                 central opening 
               
               
                 48 
                 arrow 
               
               
                 49 
                 reference line 
               
               
                 50 
                 technician 
               
               
                 51 
                 metal cuttings/shavings/parts/ 
               
               
                   
                 objects 
               
               
                 52 
                 derrick 
               
               
                 53 
                 drill string 
               
               
                 54 
                 drill bit 
               
               
                 55 
                 pump 
               
               
                 56 
                 flow line 
               
               
                 57 
                 flow line 
               
               
                 58 
                 shale shaker 
               
               
                 59 
                 tank/vessel 
               
               
                 60 
                 possum belly section 
               
               
                 61 
                 pit section 
               
               
                 62 
                 suction line 
               
               
                 63 
                 flow stream 
               
               
                 64 
                 handle 
               
               
                   
               
             
          
         
       
     
     All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise. 
     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.