Claims
- 1. A reamer for use in forming a borehole through earthen formations, comprising:
a housing having a rotational axis and an outer surface; an elongate first blade extending from said housing having a plurality of cutter elements mounted for engaging formation material as said housing is rotated, and having a radially outermost surface for contacting the borehole wall, said first blade and said housing forming an eccentric reamer body having a first diameter; at least a first movable member on said reamer body having a contact surface for contacting the borehole wall, said first movable member movable from a first position where said contact surface of said movable member falls within the circle defined by said first diameter to a second position where said contact surface of said movable member extends beyond the circle defined by said first diameter.
- 2. The reamer of claim 1 further comprising a first elongate slot in said reamer body angularly spaced from said first blade, and wherein said first movable member includes a second elongate blade mounted in said first slot for reciprocal movement from a contracted position to an extended position.
- 3. The reamer of claim 2 wherein said first blade includes first and second ends, a central segment between said ends, and inclined surfaces adjacent to said first and second ends, wherein said cutter elements are disposed on said central segment and on at least one of said inclined surfaces.
- 4. The reamer of claim 2 further comprising a plurality of cutter elements mounted on said second blade for engaging formation material when said second blade is in said extended position.
- 5. The reamer of claim 2 further comprising:
a second elongate slot formed in said housing at a position angularly disposed from said first slot and from said first blade; a third blade reciprocally disposed in said second slot and movable from a contracted position to an extended position, wherein said third blade includes a contact surface for contacting the borehole wall, said contact surface of said third blade falling within the circle defined by said first diameter when said third blade is in said contracted position, and extending beyond the circle defined by said first diameter when said third blade is in said extended position; and wherein each of said blades include upper and lower ends and an inclined surface adjacent to said upper ends.
- 6. The reamer of claim 5 further comprising a plurality of cutter elements mounted on said second blade for engaging formation material when said second blade is in said extended position.
- 7. The reamer of claim 6 further comprising a plurality of cutter elements mounted on said third blade for engaging formation material when said third blade is in said extended position.
- 8. The reamer of claim 1 further comprising an actuator for forcing said movable member to said extended position, and a latching retainer engaging said movable member and retaining said member in said retracted position until a predetermined force is applied to said movable member by said actuator.
- 9. The reamer of claim 1 further comprising a shear pin disposed through a portion of said housing and into said moveable member for retaining said moveable member in said contracted position until a predetermined shearing force is applied to said shear pin.
- 10. The reamer of claim 1 further comprising a latching retainer engaging said movable member when said movable member is in said extended position.
- 11. The reamer of claim 9 wherein said moveable member includes a second elongate blade mounted in a slot in said reamer body, said slot including a blade-facing surface, and wherein said second blade is disposed in said slot a predetermined distance from said blade-facing surface so as to form an interface between said blade-facing surface of said slot and said blade, and wherein said shear pin includes a weakened portion that is positioned within said interface when said blade is in said contracted position.
- 12. The reamer of claim 9 wherein said shear pin extends to said outer surface of said housing.
- 13. The reamer of claim 1 further comprising:
a blade insert attached to said housing by releasable fasteners, wherein said cutter elements are retained on said blade insert.
- 14. The reamer of claim 1 further comprising a first bore in said reamer body formed at a position angularly spaced from said first blade, and wherein said first movable member includes a first piston mounted in said first bore for reciprocal movement from a contracted position to an extended position.
- 15. The reamer of claim 14 wherein said first bore and said first piston extend at an acute angle relative to said rotational axis.
- 16. The reamer of claim 14 wherein said piston includes a piston head having a camming surface formed on the outer surface of said piston head for biasing said piston toward said contracted position as the reamer is withdrawn from the borehole.
- 17. The reamer of claim 16 further comprising a retainer for fixing the orientation of said camming surface and preventing rotation of said piston head.
- 18. The reamer of claim 14 wherein said piston includes a piston head extendable from said first bore, said piston head having a circumferential thin-walled segment.
- 19. The reamer of claim 14 further comprising a spring in said first bore and engaging said first piston and biasing said first piston toward said contracted position.
- 20. The reamer of claim 14 further comprising:
a second bore in said reamer body formed at a position angularly spaced from said first blade and from said first bore; and a second piston mounted in said second bore for reciprocal movement from a contracted position to an extended position.
- 21. The reamer of claim 14 further comprising a dampening means for restricting the velocity of the movement of said first piston toward said contracted position.
- 22. The reamer of claim 21 further comprising a pair of parallel fluid paths through which hydraulic fluid may flow in a first direction when tending to push said first piston to said extended position, said damping means including an orifice restricting the flow of hydraulic fluid in the direction opposite said first direction when said piston is biased toward said contracted position.
- 23. A drilling assembly for forming a borehole comprising:
a mandrel having at lease one fixed blade and having at least one moveable member mounted in a cavity in said mandrel, said moveable member having a contact surface for engaging the borehole wall; said fixed blade extending from said mandrel in a first radial direction and including a plurality of cutter elements disposed on said blade; an actuator in said mandrel extending said movable member to an extended position and a retractor in said mandrel retracting said movable member to a contracted position; a passageway in said mandrel for communicating pressurized fluid therethrough; a bore in said mandrel communicating fluid pressure from said passageway to said actuator for movement of said movable member to said extended position; and at least one retainer retaining said movable member in said contracted position until a fluid at a predetermined fluid pressure is communicated through said passageway and causes said retainer to release said moveable member.
- 24. The drilling assembly of claim 23 wherein retainer includes a shear pin having a portion extending into a bore formed in said moveable member.
- 25. The drilling assembly of claim 23 wherein said retainer includes a piston having an extension disposed in a recess formed in said moveable member.
- 26. The drilling assembly of claim 25 wherein said retainer includes a spring biasing said extension into said recess.
- 27. The drilling assembly of claim 23 wherein said actuator includes a piston moveably mounted in said mandrel and wherein said retractor includes a spring adapted to bias said piston toward said retracted position, wherein said shear pin extends through said mandrel and engages said piston, preventing movement thereof when said piston is in said contracted position.
- 28. The drilling assembly of claim 23 wherein said mandrel includes a longitudinal axis, and wherein said movable member comprises a piston mounted for reciprocal movement in a bore in said mandrel, and wherein said bore extends at an angle that is not perpendicular to said axis.
- 29. The drilling assembly of claim 28 wherein said piston bore extends at an angle of between approximately 10 and 60 degrees with respect to said axis.
- 30. The drilling assembly of claim 23 wherein said actuator includes fluid passageways allowing hydraulic fluid to extend said moveable member at a predetermined velocity, and further comprising a restrictor in said fluid passageway to restrict the velocity of said moveable member as it moves toward said contracted position.
- 31. The drilling assembly of claim 23 wherein said moveable member is an elongate blade having a radially outmost surface, and wherein said cutter elements are mounted in at least one row on said blade.
- 32. The drilling assembly of claim 24 wherein said mandrel includes an outer surface and said shear pin extends to said outer surface of said mandrel.
- 33. The drilling assembly of claim 24 wherein said shear pin includes a threaded portion that threadingly engages a threaded bore formed in said mandrel, an extending portion extending into a bore formed in said moveable member when said moveable member is in said contracted position, and a weakened portion formed between said threaded portion and said extending portion.
- 34. The drilling assembly of claim 23 wherein said fixed blade is removably fastened to said mandrel.
- 35. The drilling assembly of claim 23 wherein said actuator includes a piston movably mounted in said mandrel and said retractor includes a spring cage biased by a spring member, and wherein said shear pin extends through said mandrel and engages said spring cage preventing movement thereof when said blade is in said contracted position.
- 36. The drilling assembly of claim 23 wherein said actuator is in fluid communication with said passageway and extends said moveable member to said extended position when the pressurized fluid in said passageway reaches a predetermined pressure.
- 37. The drilling assembly of claim 23 wherein said actuator is in fluid communication with said passageway and wherein said retainer retains said moveable member in said contracted position at fluid pressures in said passageway that are less than a predetermined actuating pressure; the drilling assembly further comprising a latching retainer engaging said movable member when said movable member is in said extended position and releasably latching said member in said extended position.
- 38. A drilling assembly for cutting a borehole in earthen formation, comprising:
a drill bit; an adjustable diameter eccentric reamer above said bit having a housing, a fluid passageway through said housing, a fixed blade, and at least one movable member, said movable member actuatable to move from a first where said reamer has a first diameter to a second position where said reamer has a second diameter that is greater than said first diameter; a plurality of cutter elements mounted on said blade and having cutting faces oriented to cut formation material as said drilling assembly is rotated; at least one latching retainer releasably connecting said movable member and said housing, said retainer holding said movable member in said first position at fluid pressure within said fluid passageway less than a predetermined threshold pressure, and releasing said movable member at a fluid pressure equal to or greater than the predetermined threshold pressure.
- 39. The drilling assembly of claim 38 wherein said fixed blade comprises a blade insert releasably attached to said housing and wherein said cutter elements are mounted on said blade insert.
- 40. The drilling assembly of claim 39 wherein said moveable member is an extendable blade.
- 41. The drilling assembly of claim 38 wherein said latching retainer comprises at least one shear pin disposed in aligned bores formed in said housing and said moveable member.
- 42. The drilling assembly of claim 38 wherein said latching retainer comprises a piston member with an extension disposed in a recess formed in said movable member.
- 43. The drilling assembly of claim 42 wherein said piston extension is spring biased into said recess.
- 44. The drilling assembly of claim 41 wherein said moveable member comprises an extendable blade disposed in an elongate slot formed in said housing, said slot having a pair of side walls and said blade having a side surface facing one of said walls, wherein said shear pin includes a weakened segment that is positioned in an interface between said side wall of said slot and said blade side surface.
- 45. The drilling assembly of claim 38 wherein said reamer further comprises:
an actuator for moving said moveable member in a first direction to said extended position; a spring-loaded retainer engaging one end of said moveable member and resisting movement thereof in said first direction; wherein said latching retainer comprises at least one shear pin disposed in aligned bores formed in said housing and said spring-loaded retainer.
- 46. The drilling assembly of claim 38 wherein said latching retainer comprises at least one shear pin disposed through said housing, said shear pin having a first portion with first diameter threadingly engaging a bore in said housing, and having a second portion of second diameter that is less than said first diameter; and having a third portion between said first and second portions having a third diameter that is less than said second diameter.
- 47. The drilling assembly of claim 46 wherein said housing includes an outer surface and wherein said first portion of said shear pin is accessible from said outer surface.
- 48. The drilling assembly of claim 38 wherein said latching retainer releases said movable member without said retainer shearing.
- 49. The drilling assembly of claim 38 wherein said latching retainer comprises a spring biased member extending into a recess formed in said movable member.
- 50. A downhole tool for use in a drilling assembly in a borehole, comprising:
a housing having a rotational axis, and outer surface, and upper and lower ends for connecting the tool to adjacent components in the drilling assembly; a longitudinal fluid passageway extending between said ends; a bore through said outer surface of said housing, said bore having an inner end in fluid communication with said longitudinal fluid passageway; a piston mounted in said bore for reciprocal movement between a contracted position and an extended position, said piston including a piston head attached to a piston shaft; a latching retainer retaining said piston in said contracted position until fluid pressure in said bore behind said piston head exceeds a predetermined pressure; dampening means for slowing movement of said piston from said extended position to said contracted position.
- 51. The downhole tool of claim 50 further comprising:
a seal disposed about said piston shaft forming first and second fluid chambers in said piston bore; a first fluid passageway extending between said first and second fluid chambers and a valve in said first fluid passageway allowing fluid flow only from said first to said second fluid chamber; a second fluid passageway between said first and second fluid chambers in parallel with said first fluid passageway, said second fluid passageway including an orifice allowing fluid flow between said first and second fluid chambers in either direction.
- 52. The downhole tool of claim 50 further comprising a second latching retainer retaining said piston in said extended position.
- 53. The tool of claim 50 wherein said bore in said housing is formed at an acute angle relative to said rotational axis.
- 54. A method of passing a drilling assembly through an existing borehole having a given diameter and drilling a new borehole beneath the existing borehole, comprising:
providing a drilling assembly having a pilot bit with a pilot bit axis and an eccentric reamer above said pilot bit, said reamer including at least one extendable contact member and at least one fixed blade, wherein said fixed blade includes a plurality of cutter elements; contracting the contact members of the eccentric reamer and retaining the contact members in the contracted position; contacting the existing cased borehole with the fixed blade of the reamer and one side of the pilot bit; lowering the drilling assembly to the bottom of the cased borehole; extending the extendable contact member of the eccentric reamer; rotating the drilling assembly with the extendable contact member of the eccentric reamer in the extended position to form a new borehole beneath the existing cased borehole as the fixed blade having the cutter elements enlarges the pilot hole made by said pilot bit.
- 55. The method of claim 54 further comprising backreaming the newly formed borehole by moving the drilling assembly upward and rotating the drilling assembly to rotate the blade having the cutter elements.
- 56. The method of claim 54 further comprising:
extending said contact member to the extended position by pumping fluid at a predetermined pressure through the drilling assembly.
- 57. The method of claim 54 further comprising:
rotating the drilling assembly and drilling through a casing shoe at the bottom of the cased borehole before extending said extendable contact member of said reamer.
- 58. The method of claim 54 further comprising:
pumping drilling fluid through the drilling assembly at a first flow rate and pressure and rotating the drilling assembly with the contact members in the contracted position; pumping drilling fluid through the drilling assembly at an increased flow rate and pressure that exceeds the first flow rate and pressure to cause said extendable contact member to move to its extended position; and rotating the drilling assembly and drilling with the contact member in its extended position while pumping drilling fluid through the drilling assembly at a flow rate and pressure that is less than the increased flow rate and pressure.
- 59. A method of reaming a borehole, comprising:
providing a drilling assembly having a drill bit and an eccentric adjustable diameter reamer above said bit, said eccentric reamer including at least one extendable contact member and a fixed blade, wherein said fixed blade includes a plurality of cutter elements; contracting the contact members of the eccentric reamer and retaining them in the contracted position; lowering the drilling assembly into the borehole; extending the extendable contact members of the eccentric reamer; rotating the drilling assembly with the extendable contact members of the eccentric reamer in the extended position.
- 60. The method of claim 59 further comprising:
moving the drilling assembly upward in the borehole while rotating the drilling assembly with the extendable contact member in the extended position to back ream the borehole.
- 61. A drilling assembly for drilling a borehole through earthen formations, comprising:
a bottom hole assembly including a pilot bit and a reamer spaced apart and uphole from said pilot bit; an adjustable diameter stabilizer on said bottom hole assembly adjacent to said reamer, said adjustable diameter stabilizer comprising:
a housing having a rotational axis, an outer surface and a first diameter; a pair of moveable members having contact surfaces for contacting the borehole wall, said members moveable from a first position in said housing where said contact surfaces fall within the circle defined by said first diameter to a second position where said contact surfaces of said moveable members extend beyond the circle defined by said first diameter.
- 62. The drilling assembly of claim 61 further comprising:
actuators for forcing said movable members from said first position to said second position; and
latching retainers engaging said movable members and retaining said movable members in said first position until a predetermined force is applied to said movable members by said actuators.
- 63. The drilling assembly of claim 62 wherein said latching retainers comprise a shear pin.
- 64. The drilling assembly of claim 62 wherein said latching retainers comprise spring-biased piston members.
- 65. The drilling assembly of claim 61 wherein said moveable members comprise at least one elongate blade reciprocally mounted in a slot formed in said housing.
- 66. The drilling assembly of claim 61 wherein said moveable members comprise at least one piston reciprocally mounted in a bore formed in said housing.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part application of pending U.S. patent application Ser. No. 09/718,722, filed Nov. 22, 2000; and Ser. No. 09/603,706, filed Jun. 27, 2000, each incorporated herein by reference.
Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
09718722 |
Nov 2000 |
US |
Child |
10304842 |
Nov 2002 |
US |
Parent |
09603706 |
Jun 2000 |
US |
Child |
10304842 |
Nov 2002 |
US |