Claims
- 1. A window mill for milling a window through metal casing in a well bore, comprising:a body having a plurality of blades; and natural diamond cutters on said blades; wherein said cutters initiate cutting into said casing and mill said window in one trip into said well bore.
- 2. The window mill of claim 1 wherein said body has a longitudinal axis and said blades have a taper with respect to said longitudinal axis.
- 3. The window mill of claim 1 wherein said body has a longitudinal said blades have different angled tapers with respect to said longitudinal axis.
- 4. The window mill of claim 1 wherein said body has a longitudinal axis and said mill rotates on-center about said longitudinal axis.
- 5. The window mill of claim 1 wherein said cutters both cut said casing and drill a secondary borehole.
- 6. A window mill for milling a window through metal casing in a well bore, comprising:a body having a plurality of blades; and polycrystalline diamond cutters on said blades; wherein said cutters initiate cutting into said casing and mill said window in one trip into said well bore.
- 7. The window mill of claim 6 wherein said body has a longitudinal axis and said blades have a taper with respect to said longitudinal axis.
- 8. The window mill of claim 6 wherein said body has a longitudinal axis and said blades have different angled tapers with respect to said longitudinal axis.
- 9. The window mill of claim 6 wherein said body has a longitudinal axis and said mill rotates on-center about said longitudinal axis.
- 10. The window mill of claim 6 wherein said cutters both cut said casing and drill a secondary borehole.
- 11. A casing mill for milling a window through casing to drill a secondary borehole, comprising:a body; a plurality of blades on said body with slots extending between said blades; and each blade having a multiplicity of cutting elements including tungsten carbide cutters and diamond cutters; wherein said diamond cutters cut said casing and drill said secondary borehole.
- 12. The casing mill of claim 11 wherein said diamond cutters include natural or polycrystalline diamond cutters.
- 13. A casing mill for milling a window through casing to drill a secondary borehole, comprising:a mill body; a plurality of blades on said mill body with slots extending between said blades; and each blade having a multiplicity of cutting elements made of tungsten carbide and diamonds; wherein said diamonds mill said window borehole.
- 14. The casing mill of claim 13 wherein said diamonds include natural or polycrystalline diamonds.
- 15. The casing mill of claim 13 wherein said casing is metal casing.
- 16. The casing mill of claim 13 wherein said slots extend radially and longitudinally between the blades.
- 17. The casing mill of claim 13 wherein said blades have a width and said slots have a depth greater than said width.
- 18. A casing mill for milling a window through casing to drill a secondary borehole, comprising:a mill body; a plurality of blades on said mill body with slots extending between said blades; and each blade having a multiplicity of cutting elements made of tungsten carbide and diamonds; wherein said mill body has an axis and said cutting elements collectively form an external cutter profile comprising: an upper cylindrical gage portion; and a lower conical portion extending downwardly from said gage portion at an angle in the range of from about 10° to 20° from the axis of said mill body.
- 19. The casing mill of claim 18 wherein said lower conical portion is disposed at an angle in the range of from about 12° to 18° from the axis of said mill body.
- 20. A cutting tool for milling a window through steel casing in a well bore and being adapted to cooperate with a whipstock having a whipstock axis and ramp surface disposed at a ramp angle to the whipstock axis, the cutting tool comprising:a tool body having a body axis; a plurality of blades on said body with radially and longitudinally extending slots between said blades; and a plurality of cutting faces having polycrystalline diamond material to mill the window through the steel casing; and said cutting faces collectively forming an external profile having a gage portion with a diameter corresponding to the window to be milled through the casing, and a conical portion having a length and extending from said gage portion at an angle approximately corresponding to the ramp angle of the whipstock, said gage portion having a shorter length in the direction along said body axis than said length of said conical portion.
- 21. The tool of claim 20 wherein said conical portion has an angle in the range of from about 10° to 20° from said body axis.
- 22. The tool of claim 20 wherein said cutting faces mill said window and drill a secondary borehole in one trip into said well bore.
- 23. A method of milling a window through metal casing and drilling a secondary borehole in one trip into a well, the method comprising:rotating a mill with blades having a diamond cutting material; cutting a window in the metal casing with the mill; passing the mill through the window; and drilling a secondary borehole with the mill; wherein the diamond cutting material both cuts metal and drills borehole.
- 24. The method of claim 23 wherein said diamond material includes natural or polycrystalline diamonds.
- 25. The method of claim 23 wherein rotating a mill comprises rotating on-center about a longitudinal axis of the mill.
- 26. A cutting tool for milling a window through casing in a well bore and being adapted to cooperate with a whipstock having a whipstock axis and ramp surface disposed at a ramp angle to the whipstock axis, the cutting tool comprising:a tool body having a body axis; a plurality of blades on said body with radially and longitudinally extending slots between said blades; and a plurality of cutting faces having natural diamond material to mill the window through the casing; and said cutting faces collectively forming an external profile having a gage portion with a diameter corresponding to the window to be milled through the casing, and a conical portion having a length and extending from said gage portion at an angle approximately corresponding to the ramp angle of the whipstock, said gage portion having a shorter length in the direction along said body axis than said length of said conical portion.
- 27. The tool of claim 26 wherein said conical portion has an angle in the range of from about 10° to 20° from said body axis.
- 28. The tool of claim 26 wherein said cutting faces mill said window and drill a secondary borehole in one trip into said well bore.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation prosecution application (CPA) of U.S. patent application Ser. No. 09/303,049, filed Apr. 30, 1999 entitled One Trip Milling System, which is a continuation-in-part of U.S. patent application Ser. No. 09/021,630 filed Feb. 10, 1998, now U.S. Pat. No. 6,102,123, hereby incorporated herein by reference, which is a continuation-in-pan of U.S. patent application Ser. No. 08/642,829 filed May 3, 1996, now U.S. Pat. No. 5,771,972, hereby incorporated herein by reference, and is related to U.S. Patent Application entitled Two Trip Window Cutting System, Ser. No. 572,592, filed Dec. 14, 1995, now U.S. Pat. No. 5,657,820, hereby incorporated herein by reference, and U.S. Patent application Ser. No. 08/916,932 filed Aug. 21, 1997, now U.S. Pat. No. 5,894,889, hereby incorporated herein by reference.
US Referenced Citations (49)
Foreign Referenced Citations (9)
Number |
Date |
Country |
0 430 590 |
Jun 1991 |
EP |
2060735 |
May 1981 |
GB |
2 216 929 |
Oct 1989 |
GB |
2299105 |
Sep 1996 |
GB |
2 304 760 |
Mar 1997 |
GB |
2303158 |
Dec 1997 |
GB |
9711249 |
Mar 1997 |
WO |
WO 9813572 |
Apr 1998 |
WO |
WO 9834006 |
Aug 1998 |
WO |
Non-Patent Literature Citations (4)
Entry |
British Search and Examination Report for Application No. 0017841.8 dated Sep. 5, 2000 (3 p.). |
Track Master Sidetracking System; Feb. 24, 1995; (1 sheet). |
A-Z Grant International; Casing Sidetrack Systems; undated; (7 pgs.). |
A-Z Servco Performance Bulletin; Smith Internatioal, Inc.; 1995 (1 pg.). |
Continuation in Parts (2)
|
Number |
Date |
Country |
Parent |
09/021630 |
Feb 1998 |
US |
Child |
09/303049 |
|
US |
Parent |
08/642829 |
May 1996 |
US |
Child |
09/021630 |
|
US |