Apparatus for retrieving metal objects from a wellbore

• US 6,354,386 B1
• Filed: 06/22/2000
• Issued: 03/12/2002
• Est. Priority Date: 10/21/1999
• Status: Expired due to Term

• Current Assignee: Abrado Inc
• Original Assignee: Rattler Tools Incorporated
• Inventors: Ruttley, David J.
• Primary Examiner(s): Barrera, Ramon M.
• Application Number:
  US09/602,356
• Time in Patent Office: 628 Days
• Field of Search: 166/66.5, 166/311, 175/328
• US Class Current: 175/328
• CPC Class Codes: E21B 31/06 using magnetic means
• CPC Class Codes: E21B 37/00 Methods or apparatus for cleaning boreholes or wells E21B21/00 takes precedence

Abstract

A tool for retrieving metal objects from a wellbore has a plurality of magnet assemblies spaced longitudinally along a tool body. Each magnet assembly has a plurality of magnet members, which can be arcuate or longitudinal, covering a majority surface area of the tool body. In the embodiment of the invention having longitudinal members, magnet protectors are secured immediately adjacent to a corresponding magnet member for deflecting striking force of the metal particles being attracted to the magnet during rotation of the tool. A trap space if formed between the magnet and an adjacent magnet protector for retaining more metal particles within the magnet assemblies.

Claims

1. An apparatus for retrieving metal objects from a wellbore, comprising:

a cylindrical tool body with a central opening therethrough;

a plurality of magnet assemblies spaced longitudinally along the length of the tool body and covering a majority of surface area of said tool body, each of said magnet assemblies comprising a plurality of elongated magnet members spaced equidistantly from each other about the circumference of said tool body, each of said magnet members being provided with a magnet protector that extends outwardly from an exterior of said tool body to a distance greater than a corresponding magnet member to protect the corresponding magnet member from striking force of metal particles being attracted by the magnet member, while retaining a distance between the magnet protector and an adjacent magnet member.

2. The apparatus of claim 1, wherein each of said magnet protector members is secured on said tool body adjacent a corresponding detachable magnet member.

3. The apparatus of claim 2, wherein a particle trap space is defined between a longer side of a magnet protector member and an adjacent side of an immediately adjacent magnet member, said particle trap space being located within a magnetic field formed by individual magnet member, thereby allowing to retain metal objects within the particle trap space during operation.

4. The apparatus of claim 2, wherein each of said magnet protector members is provided with a slanted exterior surface for deflecting metal particles and preventing damage to an immediately adjacent magnet member.

5. The apparatus of claim 3, wherein the longer side of each of said magnet protector members has a length greater than a corresponding side of an immediately adjacent magnet member to thereby protect the magnet member from striking force of a metal object being attracted by the magnet.

6. The apparatus of claim 1, wherein said tool body is provided with an upper sub located above said magnet assemblies and a lower sub located below said magnet assemblies, said upper sub and said lower sub allowing connection of said body to a drill string lowered into the well bore.

7. The apparatus of claim 6, wherein diameter of said magnet assemblies is substantially equal to or less than an exterior diameter of said upper sub and said lower sub.

8. The apparatus of claim 1, wherein said tool body is provided with a plurality of recesses for receiving one side of said magnet members therein.

9. The apparatus of claim 1, further comprising retainer rings mounted between longitudinally spaced magnet assemblies for detachably securing said magnet assemblies on the tool body.

10. An apparatus for retrieving metal objects from a wellbore, comprising:

a cylindrical tool body with a central opening therethrough;

a plurality of magnet assemblies spaced longitudinally along the length of the tool body and covering a majority of surface area of said tool body, each of said magnet assemblies comprising a plurality of elongated magnet members spaced equidistantly from each other about the circumference of said tool body, each of said magnet members being provided with a magnet protector, one side of each of said magnet protectors and a side of an immediately adjacent magnet member defining a metal particles trap space.

11. The apparatus of claim 10, wherein each magnet protector member is secured on said tool body adjacent a corresponding magnet member.

12. The apparatus of claim 11, wherein each of said magnet protector members is provided with a slanted exterior surface for deflecting metal particles and preventing damage to an immediately adjacent magnet member.