Magnetic means for managing and stopping leaks in metal pipes such as we bores and pipe risers is provided. A magnetic leak arrestor comprises a spool with magnetic collar disposed thereabout. The spool has a tapered end for inserting into a pipe riser. The magnetic collar creates a seal with the pipe riser, which may the be welded in place, if desired. Additionally, a magnet may be positioned proximate a leak in a side wall of a pipe riser to seal the leak. The magnet may be shaped to conform to the shape of the pipe riser, and a seal gasket provided around an edge portion of the magnet. A slurry of magnetically active material may be provide inside the pipe to seal the leak in the side wall or to provide a blockage in the pipe riser so that killing fluids may be pumped into the well bore, if desired.

FIELD 
       [0001]    Embodiments described herein relate to use of magnetism for leak management in metal piping. More specifically, embodiments described herein relate to methods and apparatus for deploying magnets to stop or control leaks in metal piping. 
       BACKGROUND 
       [0002]    Drilling for oil is one of the world's largest industries. Unfortunately, bringing critical energy resources to consumers occasionally results in releasing oil and other substances into the environment. As was clearly demonstrated in the summer of 2010 with the massive oil release in the Gulf of Mexico, effective and efficient means for addressing leaking well bores, pipe risers, and other leaking pipes is still needed. 
       SUMMARY 
       [0003]    Embodiments disclosed herein provide an apparatus for closing a leak from an open pipe with a spool tapered to extend inside the open pipe a magnet configured to produce a magnetic field aligned with a central axis of the pipe, and a valve coupled to the spool. 
         [0004]    Other embodiments provide a method of connecting magnetically susceptible pipes by tapering an end of a first pipe to mate with a second pipe, providing a magnetic field in alignment with a central axis of the first pipe and the second pipe, and configuring the magnetic field to provide an attractive force between the first pipe and the second pipe. 
         [0005]    Other embodiments provide a method of sealing a leaking pipe by providing a ferromagnetic slurry in the leaking pipe, positioning one or more magnets to direct the ferromagnetic slurry toward an inside surface of the pipe, and using the magnetic field to harden the ferromagnetic slurry against leaks in the inside surface of the pipe. 
         [0006]    Other embodiments provide a method of plugging a well bore by providing a slurry of a ferromagnetic material into the well bore, positioning one or more magnets proximate an external surface of the well bore, accumulating the ferromagnetic material inside the well bore at a location adjacent the one or more magnets to form a flow restriction, and providing a plug mixture into the well bore to plug the well bore. 
         [0007]    Other embodiments provide a method of plugging a leaking metal pipe by applying a magnet with a gasket over the leak in the metal pipe, sealing the casket against the metal pipe, and maintaining the seal by the magnetic force of the magnet. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    So that the manner in which the above-recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0009]      FIG. 1A  is a schematic side view of an arrestor according to one embodiment. 
           [0010]      FIG. 1B  is a cross-sectional detail view of the arrestor of  FIG. 1A . 
           [0011]      FIG. 2A  is a schematic side view of a leak management apparatus according to another embodiment. 
           [0012]      FIG. 2B  is a schematic end view of a leak stopping apparatus according to another embodiment. 
           [0013]      FIG. 2C  is a schematic end view of a leak stopping apparatus according to another embodiment. 
       
    
    
       [0014]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
       DETAILED DESCRIPTION 
       [0015]      FIG. 1A  is a schematic side view of an arrestor  100  according to one embodiment. The arrestor  100  of  FIG. 1A  fits into an end of a leaking pipe to facilitate stopping the leak. The arrestor  100  comprises a spool  102  with a block valve  104 . The spool  102  is coupled to a tapered fitting  106 , which is tapered to facilitate mating with an open end of a riser, which is generally the same diameter as the spool  102 . It should be noted that the arrestor  100  of  FIG. 1A  may be sized to fit a particular leaking riser, if desired. The tapered fitting  106  enters the pipe riser, penetrating until the spool  102  contacts the pipe riser at an end  110  of the spool  102  that couples to the tapered fitting  106 . The spool  102  may contact the pipe riser by abutting an edge of the pipe riser or the end of the pipe riser may nest inside the end  110  of the spool  102 . 
         [0016]    A magnetic collar  108  disposed around the spool  102  generates a magnetic field within the spool  102  that creates an attractive magnetic force between the spool  102  and the pipe riser. The attractive force increases the contact force between the spool  102  and the pipe riser, improving the seal therebetween. The magnetic collar  108  also generates an attractive magnetic force between the arrestor  100  and the pipe riser. The magnetic collar  108  may be a permanent magnet, or preferably an electromagnet. When using an electromagnet, the arrestor  100  may be positioned with the tapered fitting  106  inside the pipe riser, and then the magnetic collar  108  may be energized to generate an attractive force between the spool  102  and the pipe riser. The attractive force seals the joint between the spool  102  and the pipe riser. If desired, the block valve  104  may be opened to admit fluids from the pipe riser into the arrestor  100  to be collected. The block valve may be left open while the arrestor is secured in place by the magnetic force. The magnetic force may also be used to hold the arrestor in place while it is welded to the pipe riser. 
         [0017]    The tapered fitting  106  may be formed integral with the spool  102 , may be welded to the spool at the end  110 , or may have a cylindrical insert portion that fits within the spool  102  and is welded to an inner wall of the spool  102 . The degree of tapering of the tapered fitting  106  may be selected to meet the requirements of different embodiments, but in most embodiments, the taper will be slight. In one example, the spool  102  has a 6 inch diameter, and the tapered fitting  106  extends beyond the end  110  of the spool  102  by about 18 inches. In this embodiment, the degree of tapering is between about 1/10 inch and about ¼ inch reduction in diameter. The tapering is generally linear, but may be non-linear in alternate embodiments. 
         [0018]      FIG. 1B  is a cross-sectional detail view of the arrestor  100  of  FIG. 1A . In the embodiment of  FIG. 1B , the tapered fitting  106  is formed integral with the spool  102 . In  FIG. 1B  the arrestor  100  is shown in mating relationship to a blowout preventer  150 , which is in turn coupled to a pipe riser  152 . In  FIG. 1B , the arrestor  100  has a ring  112  coupled to the magnetic collar  110 , the ring  112 , magnetic collar  110 , spool  102 , and tapered fitting  106  cooperatively forming a recess for accommodating the pipe riser  152 . Such construction will also accommodate a pipe riser without a blowout preventer. While the arrestor  100  is held against the pipe riser  152  and blowout preventer  105 , the ring  112  may be welded to the pipe riser  152  for improved seal. 
         [0019]    In the embodiment of  FIG. 1B , the magnetic collar  110  comprises a housing  114 , a conductor  116 , and a core  118 . The conductor  116  and core  118  constitute a magnetic assembly that may be an electromagnet. The core  118  is generally a magnetic field enhancing material, such as ferrite. The housing  114  may be any suitable structural material, such as metal, which may be lined with a dielectric material if the conductor  116  carries an electric current. 
         [0020]    The tapered fitting  106  and the spool  102  define an angle point  116 , at which the diameter of the tapered fitting  106  begins to decline. When the magnetic collar  110  is placed proximate the pipe riser  152 , the magnetic force between the magnetic collar  110  and the pipe riser  152  pulls the magnetic collar  110 , along with the spool  102 , toward the pipe riser  152  and the blowout preventer  150 , creating a sealing force at the point of contact between the magnetic collar  110  and the pipe riser  152 . The angle point  116  is generally inside the pipe riser  152  when the magnetic collar  110  contacts the pipe riser  152  to ensure the best seal. The angle point  116  may extend into the pipe riser  152  any convenient distance, but in most embodiments, the extension length will be between about ¼ and 1 pipe diameters. For example, in a 6 inch pipe system (i.e. the inner diameter of the pipe riser  152  is 6 inches), the angle point  116  will extend into the pipe riser  152  between about 1.5 inches and about 6 inches, such as about 3 inches. 
         [0021]      FIG. 2A  is a schematic side view of a leak management apparatus  200  according to another embodiment. The apparatus  200  comprises an electromagnet  202  positioned proximate a riser pipe  204  for a well. The electromagnet  202  is positioned proximate a leaking portion (not shown in  FIG. 2A ) of the riser pipe  204  to facilitate plugging the leak. The leaking portion may be a side portion or an end portion of the riser pipe  204 . A ferromagnetic fluid is provided to the interior of the riser pipe  204 , and the electromagnet  202  is energized. The electromagnet  202  generates a magnetic field inside the riser pipe  204 , at least a portion of which is substantially perpendicular to a central axis  206  of the riser pipe  204 . The lines of magnetic force propel the ferromagnetic material in the riser pipe  204  toward a leaking wall, for example the external wall, of the riser pipe  204 , creating a layer of magnetically hardened material lining the interior wall of the riser pipe  204  and covering the leaking portion. In an embodiment wherein the riser pipe  204  is leaking from an end portion thereof, the electromagnet  202  may be positioned proximate the end portion, or at any point along the pipe spaced apart from the end portion, and when energized will accumulate the ferromagnetic fluid inside the riser pipe  204  to stop or reduce the leak from the end portion. 
         [0022]      FIG. 2B  is a schematic end view of a leak stopping apparatus according to one embodiment. A magnet  206 , which may be an electromagnet or a permanent magnet, is positioned proximate a leaking portion  208  of a pipe riser  210 , which may be a well bore. The magnet  206  may have a core  212 , for example ferrite, for amplifying a magnetic field formed therein, and a coil  214  for generating a magnetic field  216  perpendicular to a central axis  218  of the pipe riser  210 . Magnetically active material, such as a slurry of ferromagnetic material for example hematite or iron filings or fragments in oil or drilling fluid, is injected into the riser pipe  210 , and the magnetic field  216  propels the magnetically active material toward the wall  220  of the pipe riser  210 , covering and sealing the leaking portion  208  thereof. 
         [0023]    In one embodiment, the magnetically active material accumulates in the pipe riser  210  at a location adjacent the magnet  206  to form a flow restriction or plug inside the pipe riser  210 . The plug is formed and held in place by magnetic force from the magnet  206 . Such a flow restriction may enable a plug or kill mixture to be pumped into the pipe riser  210  without being ejected from the pipe riser  210  by the pressure of the fluid flowing therein. 
         [0024]    In another embodiment, a side wall leak may be magnetically sealed by providing a magnet, which may be an electromagnet or permanent magnet, shaped to follow an outside surface of a pipe riser such as the pipe riser  210 . A seal or gasket may be attached to an edge of the magnet such that the seal or gasket continuously contacts the outside surface of the pipe when the magnet is in proximity to the pipe. The magnet may be placed over the side wall leak, with the seal gasket surrounding the leak. The magnetic force between the magnet and the pipe wall attracts the magnet toward the pipe wall, creating a sealing force between the seal or gasket and the pipe wall. Such a device may be used to stop a leak in a gas, oil, water, or other pipe quickly until a permanent repair can be made. 
         [0025]      FIG. 2C  is a schematic end view of a leak stopping apparatus according to another embodiment. The embodiment of  FIG. 2C  features a semi-circular magnet  250  disposed around a partial circumference of a pipe riser  260 . The pipe riser  260  may have a side wall leak that is desirous of sealing, as described above, or may be desirous of plugging or killing. The magnet  250  may be used to provide a side wall seal using an edge gasket and/or a magnetically active slurry, or to provide a flow restriction or plug of magnetically active material inside the pipe riser  260 , as described above. 
         [0026]    It should be noted that the magnetically active material to be provided to the interior of the pipe for magnetically sealing a leak is preferably not magnetized, or has only a weak magnetic moment, before it is pumped into the pipe. The magnetic moment of the material should be less that than required to immobilize the material inside the pipe so that the material will flow to the point in the pipe at which the magnet is activated. 
         [0027]    While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof.