Claims
- 1. A tractor for moving a component through a borehole, comprising:
an elongate body; aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies each being hydraulically actuated and defining engagement surfaces configured to selectively engage an inner surface of the borehole; aft and forward propulsion assemblies configured to advance said body through the borehole relative to said aft and forward gripper assemblies, respectively; a gripper control valve having a first position in which said gripper control valve directs pressurized fluid to said aft gripper assembly and a second position in which said gripper control valve directs pressurized fluid to said forward gripper assembly; and aft and forward mechanically actuated valves positioned along said body and configured to detect advancement of said body relative to said aft or forward gripper assembly, respectively; wherein said aft and forward mechanically actuated valves are in fluid communication with said gripper control valve such that fluid pressure causes said gripper control valve to change positions after said body has completed an advancement stroke through the borehole relative to said aft or forward gripper assembly.
- 2. The tractor of claim 1, wherein said aft and forward mechanically actuated valves are poppet valves.
- 3. The tractor of claim 1, further comprising an aft vent valve which allows fluid to flow from said aft mechanically actuated valve to said gripper control valve only when a pressure in the fluid exceeds a pre-selected threshold pressure.
- 4. The tractor of claim 3, further comprising an forward vent valve which allows fluid to pass from said forward mechanically actuated valve to said gripper control valve only when a pressure in the fluid exceeds a pre-selected threshold.
- 5. The tractor of claim 1, further comprising aft and forward vent valves, said aft and forward mechanically actuated valves being configured to direct fluid to pilot said aft and forward vent valves, respectively, said aft and forward vent valves being configured to direct fluid to pilot said gripper control valve.
- 6. The tractor of claim 5, further comprising a propulsion control valve, said propulsion control valve having a first position in which said propulsion control valve directs pressurized fluid to said aft propulsion assembly and a second position in which said propulsion control valve directs pressurized fluid to said forward propulsion assembly.
- 7. The tractor of claim 6, wherein said propulsion control valve is piloted by fluid pressures in said aft and forward gripper assemblies and wherein pressure exerted by said surfaces of said aft or forward gripper assembly exceeds a pre-selected threshold before said propulsion control valve changes positions.
- 8. The tractor of claim 1, wherein said aft and forward propulsion assemblies comprise aft and forward cylinders, respectively, and wherein said body further comprises aft and forward pistons which are slidably housed within said aft and foward cylinders, respectively, said aft and forward pistons being configured to be displaced by the pressurized fluid within said aft and forward cylinders for advancing said body through the borehole.
- 9. The tractor of claim 8, wherein said aft and forward mechanically actuated valves are provided on said aft and forward pistons, said aft and forward mechanically actuated valves being mechanically actuated by contact with said aft and forward cylinders.
- 10. The tractor of claim 9, wherein each of said aft and forward mechanically actuated valves is a poppet valve.
- 11. The tractor of claim 1, further comprising a propulsion control valve, said propulsion control valve having a first position in which said propulsion control valve directs pressurized fluid to said aft propulsion assembly and a second position in which said propulsion control valve directs pressurized fluid to said forward propulsion assembly.
- 12. The tractor of claim 11, wherein said propulsion control valve is piloted by fluid pressures in said aft and forward gripper assemblies and wherein pressure exerted by said surfaces of said aft or forward gripper assembly exceeds a pre-selected threshold before said propulsion control valve changes positions.
- 13. A tractor for moving a component through a borehole, comprising:
an elongate body; aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies each being hydraulically actuated and defining engagement surfaces configured to selectively engage an inner surface of the borehole; aft and forward propulsion assemblies configured to advance said body through the borehole relative to said aft and forward gripper assemblies, respectively; a gripper control valve having a first position in which said gripper control valve directs pressurized fluid to said aft gripper assembly and a second position in which said gripper control valve directs pressurized fluid to said forward gripper assembly; a propulsion control valve having a first position in which said propulsion control valve directs pressurized fluid to said aft propulsion assembly and a second position in which said propulsion control valve directs pressurized fluid to said forward propulsion assembly; a supply line for providing pressurized fluid from a supply source at a location on the surface to said gripper control valve and said propulsion control valve; and a pressure relief valve disposed within said body of the tractor for limiting fluid pressure in said supply line.
- 14. The tractor of claim 13, further comprising a start-stop valve positioned and configured to selectively stop a flow of fluid from said supply line to said gripper control valve and said propulsion control valve.
- 15. The tractor of claim 14, wherein an outlet flow from said start-stop valve pilots said pressure relief valve such that said pressure relief valve is only operational when said start-stop valve is open.
- 16. The tractor of claim 14, wherein said start-stop valve has a first position wherein said start-stop valve opens when fluid pressure in said supply line exceeds a pre-selected threshold.
- 17. The tractor of claim 16, wherein said start-stop valve has a second position wherein said start-stop valve remains closed when fluid pressure in said supply line exceeds the pre-selected threshold.
- 18. A tractor for moving a component through a borehole, comprising:
an elongate body formed with an internal passage extending longitudinally therethrough, said internal passage being adapted for receiving pressurized operating fluid from a supply line; aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies each being hydraulically actuated and defining engagement surfaces configured to selectively engage an inner surface of the borehole; aft and forward propulsion assemblies configured to advance said body through the borehole relative to said aft and forward gripper assemblies, respectively; a hydraulic valve system housed within said elongate body, said valve system being configured for directing a portion of the pressurized fluid from said internal passage to said aft or forward gripper assembly in a desired sequence for effecting movement of the tractor through the borehole; a pressure relief valve for limiting fluid pressure within said supply line, said pressure relief valve being adapted to vent a portion of the fluid from said internal passage to an annulus when the fluid pressure in said supply line exceeds a pre-selected threshold pressure; a first fluid path extending from said internal passage to said hydraulic valve system; and a second fluid path extending from said internal passage to said pressure relief valve.
- 19. The tractor of claim 18, wherein a portion of the pressurized fluid in said internal passage bypasses said first and second fluid paths.
- 20. The tractor of claim 19, further comprising a bottom hole assembly disposed along a forward end of said elongate body, said bottom hole assembly utilizing pressurized fluid from said internal passage.
- 21. The tractor of claim 18, wherein said hydraulic valve system comprises:
a gripper control valve having a first position in which said gripper control valve directs pressurized fluid to said aft gripper assembly and a second position in which said gripper control valve directs pressurized fluid to said forward gripper assembly; a propulsion control valve having a first position in which said propulsion control valve directs pressurized fluid to said aft propulsion assembly and a second position in which said propulsion control valve directs pressurized fluid to said forward propulsion assembly.
- 22. The tractor of claim 18, further comprising a fluid filter disposed along said first fluid path between said internal passage and said hydraulic valve system for preventing particles from entering said hydraulic valve system.
- 23. The tractor of claim 18 wherein more than 5% of the fluid entering said internal passage flows through said first fluid path and into said hydraulic valve system.
- 24. The tractor of claim 18 wherein said pressure relief valve is disposed within said elongate body.
- 25. The tractor of claim 18 further comprising a bottom hole assembly disposed along a forward end of said elongate body, said bottom hole assembly being powered by fluid passing through said internal passage, wherein said pressure relief valve limits the fluid pressure entering said bottom hole assembly.
- 26. The tractor of claim 18, further comprising a start-stop valve disposed along said second fluid path between said internal passage and said hydraulic valve system for preventing fluid from entering said hydraulic valve system.
- 27. The tractor of claim 26, wherein an outlet flow from said start-stop valve pilots said pressure relief valve such that said pressure relief valve is non-operational when said start-stop valve is closed.
- 28. The tractor of claim 23, wherein said start-stop valve is configured to open when fluid pressure in said second fluid path exceeds a pre-selected threshold.
- 29. An apparatus for moving through a borehole, comprising:
an elongate body formed with an internal passage extending longitudinally therethrough, said internal passage being adapted for passing pressurized operating fluid through said elongate body; aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies being hydraulically actuated for selectively engaging an inner surface of the borehole; aft and forward propulsion assemblies adapted for advancing said body through the borehole relative to said aft and forward gripper assemblies, respectively; a hydraulic valve system housed within said elongate body, said valve system being configured for receiving a portion of the pressurized fluid from said internal passage and directing the fluid to said aft or forward gripper assembly in a desired sequence for effecting movement of the tractor through the borehole; a pressure relief valve for limiting fluid pressure within said internal passage, said pressure relief valve being adapted to vent fluid from said internal passage to an annulus when the fluid pressure in said internal passage exceeds a pre-selected threshold; a first fluid path extending from said internal passage to said hydraulic valve system; and a second fluid path extending from said internal passage to said pressure relief valve.
- 30. The apparatus of claim 30, wherein said pressure relief valve is disposed within said elongate body between said aft and forward gripper assemblies.
- 31. The apparatus of claim 30, wherein said pressure relief valve is disposed at a location outside of region between said aft and forward gripper assemblies.
- 32. A tractor for moving a component through a borehole, comprising:
an elongate body; aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies being hydraulically actuated for selectively engaging an inner surface of the borehole; aft and forward propulsion assemblies adapted for advancing said body through the borehole relative to said aft and forward gripper assemblies, respectively; a gripper control valve having a first position for directing pressurized fluid to said aft gripper assembly and a second position for directing pressurized fluid to said forward gripper assembly; a propulsion control valve having first and second end surfaces, said propulsion control valve having a first position for directing pressurized fluid to said aft propulsion assembly and a second position for directing pressurized fluid to said forward propulsion assembly; a first flow path between said aft gripper assembly and said first end surface for piloting said propulsion control valve; a second flow path between said forward gripper assembly and said second end surface for piloting said propulsion control valve; and a first sequence valve disposed along said first flow path and adapted to open only when fluid pressure in said first flow path exceeds a pre-selected threshold; and a second sequence valve disposed along said second flow path and adapted to open only when fluid pressure in said second flow path exceeds a pre-selected threshold.
- 33. A tractor for moving a component through a borehole, comprising:
an elongate body; aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies being hydraulically actuated for selectively engaging an inner surface of the borehole; aft and forward propulsion assemblies adapted for advancing said body through the borehole relative to said aft and forward gripper assemblies, respectively; a gripper control valve, said gripper control valve having a first position in which said gripper control valve directs pressurized fluid to said aft gripper assembly and a second position in which said gripper control valve directs pressurized fluid to said forward gripper assembly; and a means for detecting advancement of said body relative to said aft or forward gripper assembly; wherein said means for detecting advancement of said body causes said gripper control valve to change positions after said body has completed an advancement stroke through the borehole relative to said aft or forward gripper assembly.
- 34. A tractor for moving a component through a borehole, comprising:
an elongate body; aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies being hydraulically actuated for selectively engaging an inner surface of the borehole; aft and forward propulsion assemblies adapted for advancing said body through the borehole relative to said aft and forward gripper assemblies, respectively; a gripper control valve, said gripper control valve having a first position for directing pressurized fluid to said aft gripper assembly and a second position for directing pressurized fluid to said forward gripper assembly; a propulsion control valve disposed within said body, said propulsion control valve having a first position for directing pressurized fluid to said aft propulsion assembly and a second position for directing pressurized fluid to said forward propulsion assembly; a supply line for providing pressurized fluid from a supply source at a location on the surface to said gripper control valve and said propulsion control valve; and a means for regulating the fluid pressure in said supply line.
- 35. A method of moving a component through a borehole, comprising:
providing a tractor having an elongate body, aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies being hydraulically actuated for selectively engaging an inner surface of the borehole, and aft and forward propulsion assemblies adapted for advancing said body through the borehole relative to said aft and forward gripper assemblies, respectively; attaching the component to the elongate body; conveying a pressurized fluid through a supply line to said elongate body for powering movement of the tractor; conveying pressurized fluid through said elongate body to the component; directing a portion of the pressurized fluid through a valve system in the elongate body for selectively supplying fluid to said aft and forward gripper assemblies and said aft and forward propulsion assemblies for producing movement of the tractor; regulating the pressure of the pressurized fluid in the supply line for limiting the pressure of the fluid supplied to the component and said valve system.
- 36. A method of moving a component through a borehole, comprising:
providing a tractor having an elongate body, aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies being hydraulically actuated for selectively engaging an inner surface of the borehole, and aft and forward propulsion cylinders adapted for advancing said body through the borehole relative to said aft and forward gripper assemblies, respectively; attaching the component to the elongate body; conveying a pressurized fluid through a supply line to said elongate body for powering movement of the tractor; conveying pressurized fluid through said elongate body to the component; directing a portion of the pressurized fluid through a valve system in the elongate body for selectively supplying fluid to said aft and forward gripper assemblies and said aft and forward propulsion assemblies for producing movement of the tractor; and mechanically detecting the completion of an advancement of said elongate body relative to said aft and forward propulsion cylinders for causing said aft and forward gripper assemblies to alternately engage the inner surface in a desired operational sequence.
- 37. A tractor for moving a component through a borehole, comprising:
an elongate body defining an internal passage, said internal passage being adapted for receiving pressurized fluid from a supply line; aft and forward gripper assemblies longitudinally movably engaged with said body, said aft and forward gripper assemblies each being hydraulically actuated and delivering engagement surfaces configured to selectively engage an inner surface of the borehole; aft and forward propulsion assemblies configured to advance said body through the borehole relative to said aft and forward gripper assemblies, respectively; a gripper control valve, said gripper control valve having a first position in which said gripper control valve directs pressurized fluid to said aft gripper assembly along a first flow path and a second position in which said gripper control valve directs pressurized fluid to said forward gripper assembly along a second flow path; a propulsion control valve disposed within said body, said propulsion control valve having a first position in which said propulsion control valve directs pressurized fluid to said aft propulsion assembly and a second position in which said propulsion control valve directs pressurized fluid to said forward propulsion assembly; a pressure relief valve disposed within said body of the tractor for limiting fluid pressure within said internal passage; and a reverser valve adapted for reversing said first and second flow paths for causing the tractor to move in the reverse direction.
RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional Patent Application Serial No. 60/446,644, filed Feb. 10, 2003, and U.S. Provisional Patent Application Serial No. 60/448,163, filed Feb. 14, 2003.
[0002] This application incorporates by reference the entire disclosures of (1) U.S. application Ser. No. 10/004,965, entitled “TRACTOR WITH IMPROVED VALVE SYSTEM,” filed on Dec. 3, 2001; (2) U.S. Provisional Patent Application Serial No. 60/446,644, filed on Feb. 10, 2003; and (3) U.S. Provisional Patent Application Serial No. 60/448,163, filed on Feb. 14, 2003.
Provisional Applications (3)
|
Number |
Date |
Country |
|
60446644 |
Feb 2003 |
US |
|
60448163 |
Feb 2003 |
US |
|
60525309 |
Nov 2003 |
US |