EP0465072A2 - Raccord coudé à angle variable - Google Patents

Raccord coudé à angle variable Download PDF

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Publication number
EP0465072A2
EP0465072A2 EP91305677A EP91305677A EP0465072A2 EP 0465072 A2 EP0465072 A2 EP 0465072A2 EP 91305677 A EP91305677 A EP 91305677A EP 91305677 A EP91305677 A EP 91305677A EP 0465072 A2 EP0465072 A2 EP 0465072A2
Authority
EP
European Patent Office
Prior art keywords
mandrel
bent sub
housing
relative
downhole
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91305677A
Other languages
German (de)
English (en)
Other versions
EP0465072A3 (en
Inventor
Michael Wawrzynowski
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canadian Fracmaster Ltd
Original Assignee
Canadian Fracmaster Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canadian Fracmaster Ltd filed Critical Canadian Fracmaster Ltd
Publication of EP0465072A2 publication Critical patent/EP0465072A2/fr
Publication of EP0465072A3 publication Critical patent/EP0465072A3/en
Withdrawn legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B7/00—Special methods or apparatus for drilling
    • E21B7/04—Directional drilling
    • E21B7/06—Deflecting the direction of boreholes
    • E21B7/067—Deflecting the direction of boreholes with means for locking sections of a pipe or of a guide for a shaft in angular relation, e.g. adjustable bent sub

Definitions

  • the present invention relates to downhole drilling tools and more particularly to an adjustable bent sub useful in the directional drilling of well bores.
  • bent subs are commonly used in well drilling in order to deviate the borehole from vertical to a desired angle.
  • Subs are short threaded sections of drill pipe. They are “bent”either by physical bending or machined to create an angular offset between the respective ends of the sub.
  • the bend in the sub causes the drill string to deviate from vertical as drilling progresses.
  • One drawback in the use of bent subs is that the angle is fixed. This means that numerous bent subs must be kept at the drill site to provide a selection of a range of angles which may be required as drilling progresses. The trend in the industry has, therefore, been to develop a single bent sub on which the angle can be adjusted.
  • Subs of this type are therefore referred to as "surface adjustable” bent subs, to distinguish them from subs that are “downhole adjustable”, that is, adjustable while in the well bore without being withdrawn to the surface.
  • the present invention represents an alternate structure for an adjustable bent sub.
  • an adjustable bent sub comprising cylindrical housing means having a first uphole portion and a second downhole portion, said up and downhole portions being axially offset to one another, a cylindrical mandrel having a first uphole end and a second downhole end, said up and downhole ends being axially offset to one another, the uphole end of said mandrel being receivable within said housing means for longitudinal and rotational movement relative thereto, engagement means provided between said mandrel and said housing means to prevent the relative rotation thereof when said mandrel is in a first locked position relative to said housing means, lock means actuatable to maintain said mandrel in said first locked position thereof and a second unlocked position wherein said mandrel is longitudinally movable relative to said housing means into a second unlocked position in which said mandrel and housing means are free to rotate relative to one another, piston means concentrically disposed in said housing means for longitudinal movement relative thereto and spring means concentrically disposed in said housing means for
  • adjustable bent sub 10 for use in directional well drilling generally comprises a tubular housing 12 and a tubular mandrel 14 located downhole of housing 12.
  • Housing 12 actually comprises two separate cylindrical housings, namely a tail housing 20 and an offset drive housing 22 threadedly connected together at 28. As will be described in greater detail below, housings 20 and 22 are axially offset relative to one another.
  • bent sub 10 be adjustable to provide up to 2° of total bend relative to the longitudinal axis 21 of tail housing 20.
  • Tail housing 20 is itself symmetrical about its longitudinal axis 21, which axis is colinear with the longitudinal axis of the drill string (not shown) connected uphole thereof by means of threaded connection 38.
  • externally threaded end 23 of drive housing 22 is machined at an offset angle of 1° as measured from point "x" relative to the longitudinal axis 21 of tail housing 20. This therefore results in a 1° "bend", identified as angle ⁇ , between the tail and drive housings.
  • the 1° offset of threaded end 23 is shown with some exaggeration in Figure 2.
  • Mandrel 14 comprises a cylindrical tubular barrel 40 and a tubular stinger 38.
  • the mandrel as a whole is preferably machined as a single piece, with barrel 40 including at its end 42 a threaded connection 43 used to connect the sub to a bearing assembly (not shown) which in turn supports the drill bit (also not shown).
  • Barrel 40 is symmetrical about the mandrel's longitudinal axis 46 but stinger 38 is machined at a 1° offset to barrel 40, the 1° offset being measured from point "y", the offset itself being identified as angle ⁇ .
  • Stinger 38 is otherwise symmetrical about its longitudinal axis 47 except internally at 51 where its inner diameter widens out into the inner diameter of barrel 40.
  • stinger 38 is telescopically received into drive housing 22 so that longitudinal axis 47 of stinger 38 parallels the outer surface of the drive housing.
  • the 1° bend in the connection between the drive and tail housings is completely offset by the 1° bend between barrel 40 and stinger 38, with the result that the two bends exactly cancel each other.
  • Longitudinal axis 46 of barrel 40 and longitudinal axis 21 of tail housing 20 are therefore aligned so that sub 10 as a whole is perfectly straight.
  • mandrel 14 If mandrel 14 is rotated in the clockwise direction by 180°, the two bends described above will complement each other to provide a total cumulative bend in the sub of 2° measured from point "y". More specifically, longitudinal axes 47 and 21 will intersect each other at point "y" at an angle of 2°. A further 180° rotation of mandrel 14 in either the clockwise or counterclockwise direction will again bring the total bend in the sub to 0° to thereby straighten the tool.
  • the amount of bend in the sub be incrementally adjustable, and that means be provided to lock the sub for preventing accidental or unintentional changes to the sub's bend when in use downhole.
  • connecting means 64 comprise a plurality of circumferentially spaced apart elongated splines 65 formed on the outer surface of stinger 38, and a plurality of cooperating circumferentially spaced apart elongated splines 71 formed on the inner surface of drive housing 22.
  • Splines 65 are elongated in the longitudinal direction of the stinger, extend radially outwardly from the outer surface of the stinger and are chamfered at their downhole ends as at 69 as seen most clearly from Figure 2.
  • splines 71 are also elongated in the longitudinal direction of the stinger, extend radially inwardly from the inner surface of drive housing 22 and fit slidably closely between splines 65 when the sub is locked.
  • splines 65 and 71 engage each other to prevent relative rotation between the mandrel and housing.
  • Drive housing 22 is maintained in this first locked position relative to stinger 38 by means of, for example, a removable split collar 84 comprising two C-shaped half-rings 85 connected together at opposite ends thereof by means of threaded fasteners such as bolts 90 received into threaded apertures 91.
  • collar 84 is first removed and drive housing 22, with tail housing 20 attached, is moved in the downhole direction as indicated by arrow A into a second unlocked position relative to mandrel 14.
  • Splines 71 are thereby longitudinally displaced in the downhole direction to disengage splines 65 and occupy an annular empty space 87 between the outer surface of stinger 38 and the inner surface of threaded portion 23 of drive housing 22.
  • housing 12 is displaced uphole relative to mandrel 14 back into the first locked position to re-engage splines 65 and 71. Collar 84 is then replaced to lock the mechanism at its new setting.
  • Calibrations (not shown) are provided on the outer surfaces of barrel 40 and drive housing 22 to provide an externally readable indication of the amount of bend dialled into the sub.
  • Stinger 38 is threaded at its uphole end 39 to threadably engage a correspondingly internally threaded cylindrical nut 48.
  • Nut 48 is carefully dimensioned to include a downhole end 49 which, when nut 48 is securely torqued onto the stinger, abuts against the uphole end 25 of drive housing 22. This prevents the withdrawal of mandrel 14 from housing 12, and additionally permits the application of a compressive force to the downhole end 31 of drive housing 23 against collar 84. Shoulder 47 of barrel 40, end 31 and the abutting lateral surfaces of collar 84 are carefully machined to provide a close metal-to-metal seal.
  • nut 48 is convexly rounded and abuts against a correspondingly concavely rounded surface 59 of a piston 58. This fit accommodates the eccentric movement of stinger 38 relative to the piston as mandrel 14 is rotated from time to time to set the sub's angle.
  • Piston 58 is slidably movable in the longitudinal direction of the housing against the inner bore 7 of tail housing 20. Piston 58 is sealingly compressed against nut 48 by the action of spring 50. A bearing 56 is placed between spring 50 and piston 58 to prevent torsional winding of the spring that could otherwise result when tail housing 20 is threaded to drive housing 22, or that might be caused by the rotational movement of mandrel 14 relative to housing 12.
  • drilling mud will be pumped under considerable pressure through the interior of sub 10, including the housing and mandrel, to the drill bit (not shown).
  • the mud will return to the surface through the annulus between the drill string, including sub 10, and the inner surface of the well bore. It is important that mud not escape through any of the sub's joints as this will result in a loss of circulation at the bit. Should this happen, the entire string must be removed for repairs to the sub, causing considerable delay and expense.
  • Piston 58 additionally includes a composite wear ring 51 to minimize metal-to-metal contact between itself and bore 7.
  • the rounded interface between nut 48 and piston 58 is sealed by an O-ring 62.
  • a metal-to-metal seal 101 is made in the seam between the drive and tail housings, with additional sealing provided by O-ring 30.
  • Another O-ring 88 seals the downhole end of drive housing 22 against stinger 38.
  • a second wear ring 90 is received into a circumferential groove 91 formed in the inner surface of the drive housing, the purpose of the wear ring being to minimize metal-to-metal wear between the drive housing and stinger 38.
  • Oil plugs 108 are provided in the outer surface of housing 12 for the addition of oil or grease to the annular spaces between the mandrel and housing in the zone between these plugs.
  • Assembly of the sub consists of sliding drive housing 22 over stinger 38, followed by the connection of threaded nut 48 which is torqued tight.
  • Spring 50, bearing 56 and piston 58 are preloaded into tail housing 20, which is then torqued into threaded engagement with drive housing 22.
  • Adjustments to the sub's bend are usually made at the surface when the sub is threaded to a piece of drill pipe or other uphole equipment suspended from a derrick.
  • Barrel 40 may be clamped in the derrick's rotary table, collar 84 is removed, the derrick applies a compressive force to move housing 12 downwardly towards shoulder 47 of barrel 40 to unlock splines 65 and 71, and the required bend can then be dialled in using a pair of tongs to grip and twist the housing.
  • the compressive force from the derrick is removed and spring 50 helps restore the mandrel and housing to their spaced apart positions for reattachment of collar 84.
  • the chamfering on-splines 65 facilitate their engagement with splines 71.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)
EP19910305677 1990-06-26 1991-06-24 Adjustable bent sub Withdrawn EP0465072A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA002019898A CA2019898A1 (fr) 1990-06-26 1990-06-26 Raccord cintre reglable
CA2019898 1990-06-26

Publications (2)

Publication Number Publication Date
EP0465072A2 true EP0465072A2 (fr) 1992-01-08
EP0465072A3 EP0465072A3 (en) 1992-12-16

Family

ID=4145345

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910305677 Withdrawn EP0465072A3 (en) 1990-06-26 1991-06-24 Adjustable bent sub

Country Status (4)

Country Link
EP (1) EP0465072A3 (fr)
AU (1) AU7932191A (fr)
CA (1) CA2019898A1 (fr)
NO (1) NO912480L (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0561072A1 (fr) * 1992-03-16 1993-09-22 Canadian Fracmaster Ltd Boîtier de raccord coudé réglable
WO1993023652A1 (fr) * 1992-05-21 1993-11-25 Baroid Technology, Inc. Appareil d'orientation pour trepan
US5441119A (en) * 1992-10-23 1995-08-15 Transocean Petroleum Technology As Directional drilling tool

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4303135A (en) * 1977-08-18 1981-12-01 Benoit Lloyd F Directional drilling sub
US4596294A (en) * 1982-04-16 1986-06-24 Russell Larry R Surface control bent sub for directional drilling of petroleum wells
US4745982A (en) * 1986-11-28 1988-05-24 Wenzel Kenneth H Adjustable bent sub
US4884643A (en) * 1989-01-17 1989-12-05 392534 Alberta Ltd. Downhole adjustable bent sub
US5052501A (en) * 1990-08-01 1991-10-01 Douglas Wenzel Adjustable bent housing
EP0497421A1 (fr) * 1991-02-01 1992-08-05 Anadrill International SA Pièce condée réglable

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4303135A (en) * 1977-08-18 1981-12-01 Benoit Lloyd F Directional drilling sub
US4596294A (en) * 1982-04-16 1986-06-24 Russell Larry R Surface control bent sub for directional drilling of petroleum wells
US4745982A (en) * 1986-11-28 1988-05-24 Wenzel Kenneth H Adjustable bent sub
US4884643A (en) * 1989-01-17 1989-12-05 392534 Alberta Ltd. Downhole adjustable bent sub
US5052501A (en) * 1990-08-01 1991-10-01 Douglas Wenzel Adjustable bent housing
EP0497421A1 (fr) * 1991-02-01 1992-08-05 Anadrill International SA Pièce condée réglable

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0561072A1 (fr) * 1992-03-16 1993-09-22 Canadian Fracmaster Ltd Boîtier de raccord coudé réglable
WO1993023652A1 (fr) * 1992-05-21 1993-11-25 Baroid Technology, Inc. Appareil d'orientation pour trepan
GB2281332A (en) * 1992-05-21 1995-03-01 Baroid Technology Inc Drill Bit Steering
GB2281332B (en) * 1992-05-21 1995-09-13 Baroid Technology Inc Drill Bit Steering
US5441119A (en) * 1992-10-23 1995-08-15 Transocean Petroleum Technology As Directional drilling tool

Also Published As

Publication number Publication date
NO912480D0 (no) 1991-06-25
EP0465072A3 (en) 1992-12-16
CA2019898A1 (fr) 1991-12-26
NO912480L (no) 1991-12-27
AU7932191A (en) 1992-01-02

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