Abstract:
A magnetic tool for use in removing metal debris from a well is disclosed, the tool having inserts that may be safely installed and removed by a method using a placement screw to prevent pinching. The inserts comprised of a sleeve with a lead end and a follow end. The inserts also containing a plurality of magnets.

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention relates generally to tools and methods used to remove metal from wells. 
     2. Description of Related Art 
     During a drilling process metal debris is often formed within a well. Where that debris is magnetic, typically from being sufficiently ferrous, it may be removed by placing a tool having magnets within the well. The magnet will attract the magnetic debris from within the well, especially if that debris is dispersed in fluids within the well. Removal of the magnetic debris can reduce processing costs of fluids that are removed form the well and aid production from the well in other ways generally known in the art. 
     The tools currently used either have multiple small magnets or large magnetic inserts. Either way the magnets have to be secured to the tools to insure that they survive the trip down the well and back up in an environment of extreme temperature and pressure. Upon removal of the tool from the well the magnets typically are removed from the tool for cleaning and inspection before being used again. Where the magnets are arranged in large inserts they are very powerful and can be difficult and dangerous to install and remove from the tools. There is a high risk of pinching skin or body parts when dealing with these powerful magnet inserts. 
     A need exists, therefore, for a magnetic tool with powerful magnet inserts that are safe to install and remove from a tool, an insert to help achieve this goal and a method for safely installing and removing inserts from a magnetic tool. 
     All references cited herein are incorporated by reference to the maximum extent allowable by law. To the extent a reference may not be fully incorporated herein, it is incorporated by reference for background purposes and indicative of the knowledge of one of ordinary skill in the art. 
     BRIEF SUMMARY OF THE INVENTION 
     The problems presented in the art are addressed by a magnetic insert for a magnetic tool used in a well, the insert comprising: a tubular sleeve with a first end and a second end opposite the first end, an outwardly facing top surface and an inwardly facing bottom surface; a lead end securely attached to the first end; a follow end securely attached to the second end; a plurality of magnets within the sleeve, each magnet having a north pole and an opposite south pole, the magnets arranged in the sleeve such that each magnet has the same pole directed towards the top surface; and the follow end having a smooth bore for receiving a securing bolt and a threaded bore for receiving a placement bolt. 
     The problems presented in the art are addressed by a tool for removing metal from a well, the tool comprising: a body having a connector at a top end of the body and a plurality of recesses about a perimeter of the body, each recess having a tool tab at one end; a plurality of magnetic inserts sized to fit the recesses, each insert comprising: a tubular sleeve with a first end and a second end opposite the first end, an outwardly facing top surface and an inwardly facing bottom surface; a lead end securely attached to the first end; a follow end securely attached to the second end; a plurality of magnets within the sleeve, each magnet having a north pole and an opposite south pole, the magnets arranged in the sleeve such that each magnet has the same pole directed towards the top surface; and the follow end having a smooth bore for receiving a securing bolt and a threaded bore for receiving a placement bolt and washer. 
     The problems presented in the art are addressed by a method for safely securing and removing magnetic inserts from a magnetic tool used in a well, the method comprising: providing a tool having: a body having a connector at a top end of the body and a plurality of recesses about a perimeter of the body, each recess having an associated tool tab at one end of the recess and an associated threaded tool bore at the opposite end; a plurality of magnetic inserts sized to fit the recesses, each insert comprising: a tubular sleeve with a first end and a second end opposite the first end, an outwardly facing top surface and an inwardly facing bottom surface; a lead end securely attached to the first end; a follow end securely attached to the second end; a plurality of magnets within the sleeve, each magnet having a north pole and an opposite south pole, the magnets arranged in the sleeve such that each magnet has the same pole directed towards the top surface; and the follow end having a smooth bore for receiving a securing bolt and a threaded bore for receiving a placement bolt and washer; threading a placement bolt through a washer and through the threaded bore in the follow end of a first magnetic insert; placing the lead end of the first insert under a first tool tab while holding the follow end of the first insert away from the tool; moving the follow end of the insert towards the recess associated with the first tool tab until the placement bolt is within the recess; unscrewing the placement bolt to lower the sleeve into the recess of the tool; unscrewing the placement bolt from the threaded hole completely; and placing a securing bolt through a washer and through the smooth bore of the follow end of the insert into the threaded tool bore associated with the first tool tab. 
     Other objects, features, and advantages of the present invention will become apparent with reference to the drawings and detailed description that follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a tool for removing metal from a well; 
         FIG. 2  is a perspective view of the tool of  FIG. 1  with a magnetic insert partially installed in the tool; 
         FIG. 3  is a top view of a magnetic insert from the tool of  FIG. 1 ; 
         FIG. 4A  is a side view of the magnetic insert of  FIG. 2 ; 
         FIG. 4B  is a sectional side view of the magnetic insert of  FIG. 3 ; 
         FIG. 5A  is a close up view of the lead end of the insert of  FIG. 3 ; 
         FIG. 5B  is a close up view of the lead end of the insert of  FIG. 4 ; 
         FIG. 6A  is a close up view of the follow end of the insert of  FIG. 3 ; 
         FIG. 6B  is a close up view of the follow end of the insert of  FIG. 4 ; 
         FIG. 7A  is a close up view of the follow end of the insert of  FIG. 3  with a set screw; and 
         FIG. 7B  is a close up view of the follow end of the insert of  FIG. 4  with a set screw. 
     
    
    
     DETAILED DESCRIPTION 
     All references cited herein are incorporated by reference to the maximum extent allowable by law. To the extent a reference may not be fully incorporated herein, it is incorporated by reference for background purposes and indicative of the knowledge of one of ordinary skill in the art. 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical mechanical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the invention, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. 
       FIG. 1  is a perspective view of a tool  10  for removing metal from a well. Tool  10  is lowered into a well by its connector  12  to remove metal debris, such as worn parts of bits or other tools, from the fluid in a well. Tool  10  has several recesses  14  about it perimeter running lengthwise along tool  10 . Each recess  14  has a tool tab  16  at one end and a threaded tool bore  18  at the opposite end the tab  16 . Each recess  14  may accommodate a magnetic insert  20 . 
       FIG. 2  is a perspective view of the tool  10  of  FIG. 1  with a magnetic insert  20  partially installed in the tool  10 . The magnetic insert  20  has a sleeve  22  holding the magnets  24 , as will be described in more detail below. The sleeve is capped at one end by a lead end piece  26  and at the opposite end by a follow end piece  28 . The lead end piece  26  is positioned under tab  16  of a recess  14 . The follow end piece  28  is spaced from recess  14  by a placement bolt  30 . The partially removed inserts  20  may either be new inserts  20  being placed or old inserts  20  being removed, as will be discussed below. 
       FIG. 3  is a top view of a magnetic insert  20  from the tool  10  of  FIG. 1 . The insert  20  has a sleeve  22  capped by a lead end piece  26  and a follow end piece  28 . Lead end piece  26  may be rounded as shown to aid in placement and orientation. Follow end piece  28  has a tapped hole  32  and a smooth bored slot  34 . Tapped hole  32  is threaded to receive placement bolt  30 . Smooth bored slot  34  is preferably recessed to receive securing bolt  36  and washer  46 . Sleeve  22  is a tube of ferromagnetic material, such as type 410 stainless steel. Lead end piece  26  and follow end piece  28  are typically formed of non-ferrous material, such as type 303 stainless steel. Lead end piece  26  and follow end piece  28  are welded to sleeve  22  to seal the sleeve. 
       FIG. 4A  is a side view of the magnetic insert  20  of  FIG. 2 . Lead end  26  is thinner than sleeve  20  to allow lead end  26  to fit under tab  16  as discussed above. Follow end  28  may also be thinner to reduce any interference between the securing bolt  36  and operation of the tool  10 . To position insert  20  into tool  10  securing bolt  36  and washer  46  are removed and placement bolt  30  is fully threaded through tapped hole  32 . 
     Returning to  FIGS. 1 and 2 , lead end  26  is placed under tab  16  of tool  10  while follow end  28  is held away from recess  14 . Follow end  28  may then be lowered until placement bolt  30  is in recess  14 , as shown in  FIG. 2 . Follow end  28  may then be tapped with a non-metallic hammer to secure lead end  26  under tab  16  in recess  14 . Placement bolt  30  is then partially unscrewed from tapped hole  32  to allow follow end piece  28  to be drawn closer to recess  14  by magnets  24 . Follow end  28  may then be tapped with a non-metallic hammer to further secure lead end  26  under tab  16  in recess  14 . This process is repeated as necessary to lower insert  20  into recess  14  of tool  10  while keeping lead end  26  secure behind tab  16 . Once placement bolt  30  is fully unthreaded follow end piece  28  will be resting in recess  14  and smooth bore  34  should be aligned with threaded tool bore  18  in recess  14 . Securing bolt  36  is placed through smooth bore with washer  46  placed over the threads of the securing bold, above the unthreaded follow end piece  24  and threaded into tool bore  18  to secure follow end  28  and insert  20  into tool  10 . Washer  46  is preferably a locking type to prevent backing of securing bolt  36 . A setscrew  44  may be secured in tapped hole  32  to prevent debris build up in tapped hole  32  during use and further secure insert  20  as shown in  FIGS. 1 and 2 . Placement bolt  30  allows for insert  20  to be lowered into recess  14  without the need of a body part, such as a finger, being between insert  20  and tool  10  that could be pinched. This arrangement also has fewer parts than comparable units in the prior art to reduce loss or failure. 
     To remove insert  20  from tool  10  follow end  28  may first need to be wiped clear of any debris from use. Setscrew  44 , if used, and securing bolt  36  and washer  46  may then be removed. Placement bolt  30  is then threaded through tapped hole  32  to lift follow end piece  28  from recess  14 . Once placement bolt  30  is fully threaded through tapped hole  32  follow end  28  should be safely clear of tool  10  and insert  20  may be removed from tool  10  by sliding lead end  26  out from under tab  16 . 
       FIG. 4B  is a sectional side view of the magnetic insert  20  of  FIG. 3 . The sectional view allows magnets  24  to be shown. In this example there are 4 magnets  24  positioned within sleeve  22 , although the number of magnets  24  will depend on the size of the insert. Each magnet  24  has a north pole  38  and a south pole  40 . The magnets  24  are placed within sleeve  22  so that they all have the same pole facing up. For example, all of the magnets  24  may be placed into the sleeve  22  with their north poles  38  facing up as shown. Individual magnets  24  may be of various length, width and thickness dimensions. Individual magnets  24  of various thickness dimensions may consist of a single magnet  24  with a specific thickness or it may consist of two or more magnets  24  that are stacked on top of each other with the magnetic north and south poles of the stacked magnets  24  facing and contacting each other to create a thicker, more powerful magnet circuit as compared to a thinner single magnet  24  or thinner stack of magnets  24  with the thickness of magnets  24  or stack of magnets  24  being level across the entirety of the north and south poles for a consistent magnetic circuit from end to end within the sleeve  22 . Magnets  24  are typically raw magnets such as Neodymium Iron Boron, Ultra High Temperature Neodymium Iron Boron, Samarium Cobalt, Ceramic, or AlNiCo. N40UH (Neodymium Iron Boron Ultra High Temperature Rated grade 40) raw magnets.  24  may be Nickel coated for corrosion prevention. SmCo26 (Samarium Cobalt grade 26) raw magnets  24  may be non-coated in some applications. 
     Also visible from this view is pole piece  42 . Pole piece  42  has two primary functions. Pole piece  42  is placed on the bottom of sleeve  22  so that in use pole piece  42  is between magnets  24  and tool  10 . Pole piece  42  aids in the assembly of insert  20  by providing a surface for loading the magnets  24  within sleeve  22 . Pole piece  42  also serves to focus the magnetic field of magnets  24  out from the perimeter of tool  10 . Pole piece  42  is made of ferromagnetic material, such as 1018 carbon steel. 
       FIG. 5A  is a close up view of the lead end  26  of the insert  20  of  FIG. 3 . Lead end  26  is shown inserted into sleeve  22  such that lead end  26  may be welded to seal sleeve  22 . Lead end  26  is shown rounded to aid in positioning within recess  14  and under tab  16 . 
       FIG. 5B  is a sectional view of the lead end  26  of the insert  20  of  FIG. 5A . Lead end  26  is shown sealing sleeve  22  with magnets  24  and pole piece  42  within sleeve  22 . Lead end  26  may abut magnets  24  and pole piece  42 . Pole piece  42  may be slightly shorter than magnets  24  to insure that magnets  24  are pressed tightly together within sleeve  22 . 
       FIG. 6A  is a close up view of the follow end  28  of the insert  20  of  FIG. 3 . Follow end  28  is inserted within sleeve  22  and welded in place to seal sleeve  22 . Tapped hole  32  and smooth bore hole  34  are shown with placement bolt  30  and securing bolt  36  respectively. Smooth bore hole  34  is shown as a slotted bore to compensate for any alignment issues once insert  20  is installed in recess  14 . 
       FIG. 6B  is a sectional view of the follow end  28  of the insert  20  of  FIG. 6A . In sectional view it is easier to see the tapped hole  32  and smooth bore  34 . Magnets  24  and pole piece  42  are also shown within sleeve  22  which may be of various width, length and height dimensions depending on the width, length and thickness of magnets  24  installed within the sleeve and whether the magnets  24  consist of two or more magnets  24  that are stacked on top of each other with the magnetic north and south poles of the stacked magnets  24  facing and contacting each other to create a thicker, more powerful magnet circuit as compared to a thinner single magnet  24  or thinner stack of magnets  24  with the thickness of magnets  24  or stack of magnets  24  being level across the entirety of the north and south poles for a consistent magnetic circuit from end to end within the sleeve  22 . 
       FIG. 7A  is a close up view of the follow end  28  of the insert  20  of  FIG. 3  with a set screw  44 . Follow end  28  is inserted within sleeve  22  and welded in place to seal sleeve  22 . Tapped hole  32  and smooth bore hole  34  are shown with set screw  44  and securing bolt  36  respectively. Smooth bore hole  34  is shown as a slotted bore to compensate for any alignment issues once insert  20  is installed in recess  14 . Set screw  44  prevents debris build up in threaded bore  32  so that placement bolt  30  may be inserted more easily after tool  10  has been deployed. Set screw  44  may also be tightened to provide additional tension on securing bolt  36  once insert  20  is secured in tool  10 . Washer  46  and set screw  44  may both be used to lock securing bolt  36  into place, or only one may be used or neither may be used. 
       FIG. 7B  is a close up view of the follow end  28  of the insert  20  of  FIG. 4  with a set screw  44 . In sectional view it is easier to see the tapped hole  32  and smooth bore  34 . Magnets  24  and pole piece  42  are also shown within sleeve  22 . Set screw  44  is shown in threaded bore  32 . 
     It should be apparent from the foregoing that an invention having significant advantages has been provided. While the invention is shown in only a few of its forms, it is not just limited but is susceptible to various changes and modifications without departing from the spirit thereof.