Bore hole tool with magnetic blade retention

Abstract

A bore hole tool which uses magnetic means to retain the tool in a closed or collapsed position when in a non-operating mode while able to release from the magnetic retention to an open or enlarged position when said tool is in an operating mode when rotation is applied or fluid is pumped through said tool.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional patent application Ser. No. 61/271,414 filed Jul. 21, 2009 by Alan L. Nackerud, which is incorporated by reference herein.

BACKGROUND AND FIELD OF INVENTION

This invention generally relates to bore hole tools, including, but not limited to underreamers, section mills, casing cutters, casing scrapers and drill string centralizers, hereinafter collectively referred to as Bore Hole Tool(s). Most conventional Bore Hole Tools which expand in diameter when operating have expandable blades or cutters which are opened by pump pressure and returned to a closed position by a spring or other mechanical retraction device when not in use. However, some Bore Hole Tools do not have a spring or other mechanical retraction device for said blades but rather are free to rotate on their axis at any time, and are activated or opened when fluid is pumped and expelled through the blades and/or rotation of the drill string is applied. In a vertical well bore the Bore Hole Tool blades close by gravity upon cessation of pumping and cessation of rotation which allows the drill string to be advanced or retracted within the bore hole without the blade or blades catching the side walls of the well bore. One problem with said tools without a mechanical retraction device is that in a horizontal or angled well bore they do not always readily close or remain in a closed position when desired due to gravity pulling the rotatable downward blade against the well bore sidewall. Advancement or retraction of the drill string in a non-operating mode can thereby be problematic. The present invention is an improvement to said Bore Hole Tools and alleviates this problem by having one or more retention magnets positioned in the body or blades such to keep the blades in a closed position when fluid is not being pumped through the drill string and the drill string is not being rotated. At least one full slow rotation of the drill string allows the blade or blades to close into the body whereby the retention magnets keep the blades retracted in the body in a non-operating mode. The retention magnets are of a predetermined sufficient strength to keep the blades in a closed position when fluid is not being pumped through the drill string and the drill string is not being rotated, however said magnets are of a predetermined limited strength which allows the blades to open upon sufficient pumping or rotation. The present invention thereby allows the drill string and Bore Hole Tool to advance or retract within the bore hole when in a non-operating mode.

SUMMARY OF THE INVENTION

The above and other advantages and features will become more readily appreciated and understood from a consideration of the following detailed description of different embodiments when taken together with the accompanying drawings in which:

DRAWINGS-FIGURES

FIG. 1 is a side view of assembled tool in closed position;

FIG. 2 is a side view of assembled tool in closed position rotated 90 degrees;

FIG. 3 is a section view of assembled tool through the magnetic retention device with blades in a closed position;

FIG. 4 is a side view of assembled tool in an open position;

DRAWINGS-REFERENCE NUMERALS

• 10. body
• 11. blade one
• 12. blade two
• 13. blade one magnet
• 14. blade one magnet opening
• 15. blade one magnet encasement material
• 16. blade two magnet
• 17. blade two magnet opening
• 18. blade two magnet encasement material
• 19. blade cutters
• 20. blade fluid ports
• 21. blades slot
• 22. blades main fluid bores
• 23. body main fluid bores

DETAILED DESCRIPTION

Referring to the drawings, there is illustrated in

FIGS. 1 through 4 one form of the present invention being an improved Bore Hole Tool with magnets 13, 16 for steel blades 11, 12 retention in the body 10 when the Bore Hole Tool is in a closed position and in a non-operating mode. In FIG. 1 the Bore Hole Tool has a top threaded connection and a bottom threaded connection to allow connection to a drill string. The Bore Hole Tool has a bore through the top threaded connection. Said bore intersects angled bores in the body 10 which lead to and intersect body main fluid bores 23 which run down both sides of the body 10 which then intersect angled bores back into a bore leading out the bottom threaded connection and into the preceding drill string and any preceding bottom hole assembly. The Bore Hole Tool body main fluid bores 23 also intersect bores into blades 11, 12 and main fluid blade bores 22 whereby fluid can travel into and through blades 11, 12 and expel out blade fluid ports 20 which assist the Bore Hole Tool opening. The blades 11, 12 are free to move on their pin or bearing axis near the top of the Bore Hole Tool whereby rotation of the drill string allows centrifugal force to also assist opening of the Bore Hole Tool blades 11, 12. When the Bore Hole Tool is in a non-operating mode, retraction of the blades 11, 12 back into the Bore Hole Tool body 10 is caused by cessation of pumping fluid and cessation of rotation of the drill string whereby gravity causes the blades to close by gravity in a vertical well bore. In an angled or horizontal well bore, closure of the blades 11, 12 is assisted by one or more slow rotations of the drill string whereby gravity cause the blades 11, 12 to retract into the body 10. The blades remain in a closed or retracted position by one or more magnets 13, 16 which are placed in the magnet openings 14, 17 in the body 10. This is especially helpful when the Bore Hole Tool is working in an angled or horizontal well bore where gravity would otherwise pull the blade able to rotate downward to an open position whereby it may catch the side wall of the well bore. The magnets 13, 16 could also be positioned in the blades 11, 12 rather than the body 10 with the same result of blade retention. The magnets 13, 16 are retained in the magnet openings 14, 17 by encasement material 15, 18 being an epoxy or other encasement material means or mechanical suspension means such as pins. The magnets 13, 16 can be in a plate form or cylindrical or other shape. The magnets 13, 16 are suspended in the slot within the encasement material 15 such that direct contact with the metallic Bore Hole Tool body 10 is not made or minimized whereby the magnetic force is maintained. The magnets 13, 16 are positioned to make contact, or near contact with the blades 11, 12 when said blades 11, 12 are in a closed position. The magnets 13, 16 are of sufficient size, shape and magnetic strength and positioned such in the body 10 to allow retention of the blades 11, 12 in a closed position. The magnets 13, 16 are however of a limited size, shape and magnetic strength and positioned such in the body 10 to allow opening of the blades 11, 12 when adequate fluid is pumped through the Bore Hole Tool or adequate rotation of the drill string is made to actuate the Bore Hole Tool.

It is therefore to be understood that even though numerous characteristics and advantages of the present embodiment have been set forth in the foregoing description, together with the details of the structure and function of the embodiment, the disclosure is illustrative only, and changes may be made within the principles of the embodiment to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed and reasonable equivalents thereof.

Claims

1. A bore hole tool apparatus blade retention system which uses magnetic means in the body to keep moveable blades in a closed position when not in an operating mode, whereby said magnetic means are of a predetermined strength to retain said blades in a closed position in a vertical, angled or horizontal well bore, and whereby said magnetic means are of a predetermined limited strength to allow the blades to open to an operating position when rotation of the drill string is actuated or fluid is pumped through the drill string and said tool blades.

2. In an apparatus according to claim 1 wherein said magnetic means are positioned adjacent to the distal end of the blades.

3. In an apparatus according to claim 2 wherein said magnetic means are retained in the body by hardened fluid encasement material.

4. In an apparatus according to claim 2 wherein said magnetic means are retained in the body by pin or bolt means.

5. A bore hole tool blade retention system which uses magnetic means in the blades to keep moveable blades in a closed position when not in an operating mode, whereby said magnetic means are of a predetermined strength to retain said blades in a closed position in a vertical, angled or horizontal well bore, and whereby said magnetic means are of a predetermined limited strength to allow the blades to open to an operating position when rotation of the drill string is actuated or fluid is pumped through the drill string and said blades.

6. In an apparatus according to claim 5 wherein said magnetic means are positioned at the distal end of the blades.

7. In an apparatus according to claim 6 wherein said magnetic means are retained in the blades by hardened fluid encasement material.

8. In an apparatus according to claim 6 wherein said magnetic means are retained in the blades by pin or bolt means.

9. A bore hole tool apparatus blade retention system which uses magnetic means in the body to keep moveable blades in a closed position when not in an operating mode, whereby said magnetic means are of a predetermined strength to retain said blades in a closed position in a vertical, angled or horizontal well bore, and whereby said magnetic means are of a predetermined limited strength to allow the blades to open to an operating position when rotation of the drill string is actuated or fluid is pumped through the drill string and said tool blades, wherein said magnetic means are positioned adjacent to the distal end of the blades and retained in the body by hardened fluid encasement material.