WO2012171643A2 - Two-centre rotary boring bit and method for deepening an existing well - Google Patents

Two-centre rotary boring bit and method for deepening an existing well Download PDF

Info

Publication number
WO2012171643A2
WO2012171643A2 PCT/EP2012/002510 EP2012002510W WO2012171643A2 WO 2012171643 A2 WO2012171643 A2 WO 2012171643A2 EP 2012002510 W EP2012002510 W EP 2012002510W WO 2012171643 A2 WO2012171643 A2 WO 2012171643A2
Authority
WO
WIPO (PCT)
Prior art keywords
tool
pilot
blades
pilot tool
bit
Prior art date
Application number
PCT/EP2012/002510
Other languages
French (fr)
Other versions
WO2012171643A3 (en
Inventor
Sébastian DESMETTE
Abdelhakim Hahati
Benoit Deschamps
Original Assignee
Omni Ip 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 Omni Ip Ltd. filed Critical Omni Ip Ltd.
Priority to US14/125,413 priority Critical patent/US20140131111A1/en
Priority to EP12732786.4A priority patent/EP2721242B1/en
Publication of WO2012171643A2 publication Critical patent/WO2012171643A2/en
Publication of WO2012171643A3 publication Critical patent/WO2012171643A3/en

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/26—Drill bits with leading portion, i.e. drill bits with a pilot cutter; Drill bits for enlarging the borehole, e.g. reamers
    • E21B10/265—Bi-center drill bits, i.e. an integral bit and eccentric reamer used to simultaneously drill and underream the hole

Definitions

  • the invention relates to rotary bits, especially to bits for drilling wells in fluid deposits such as oil or natural gas.
  • the invention more particularly relates to a rotary bit of the bi-center type comprising a pilot tool followed by a widening tool.
  • Drill bits are drill tools that are attached to the end of a drill string to drill a well to a useful underground deposit, such as a deposit of oil, gas, water, ore. or coal.
  • the drill string is supported by a tower located on the surface.
  • a drilling mud is generally injected into the drill string to exit through the bit and back to the surface by the annular space formed between the drill string and the well being drilled.
  • the function of the drilling mud is to cool the drill bit and to remove debris from the borehole to the surface.
  • Bi-center rotary bits are well known in drilling technology, where they are used for drilling large diameter wells or for deepening while widening pre-existing wells.
  • These known drill bits described in particular in US 5 678 644 and US 2002/0104688 comprise a pilot tool, followed by an expanding tool, these two tools forming a rigid unitary assembly.
  • the pilot tool comprises a body of revolution with an axial core carrying, at one end, radial and frontal blades provided with cutting elements and, at the other end, a threaded end to fix it to the drill string.
  • the expanding tool is inserted between the pilot tool and the threaded end. It includes a body with cutting elements on only a portion of its periphery, so that it is asymmetrical, its cutting elements acting in the manner of a bur to expand the well being drilled, behind the pilot tool .
  • the invention aims to overcome the aforementioned disadvantages of known drills described above.
  • the object of the invention is more particularly to provide a rotary bit of the bi-center type, of a new design, capable of preventing unbalance of the bit.
  • Another object of the invention is to provide a bi-center type drill bit whose efficiency is improved and which allows a high precision drilling.
  • a further object of the invention is to improve the efficiency of the bi-center type rotary bits by allowing higher drilling speeds.
  • the invention also aims to enhance the accuracy of the geological analysis of the massif during drilling.
  • a further object of the invention is to provide a bi-center bit which is specially adapted for use in a pre-existing well to deepen it, especially a well whose diameter is substantially equal to the greatest transverse dimension of the tool. bit enlarger.
  • the invention relates to a bi-center rotary bit for drilling wells, comprising, on the one hand, a pilot tool comprising a body of revolution with an axial core and radial blades carrying cutting elements and, on the other hand, an expanding tool placed behind the pilot tool and offset laterally thereto;
  • the bit is characterized in that the front face of the pilot tool has an axial central zone which is devoid of cutting elements to allow the formation of an axial core, said central zone being in communication with a cavity located between two blades of the pilot tool and used to evacuate the core towards the periphery of the bit.
  • 'back', 'front', 'behind', 'front' and 'posterior' are defined with respect to the direction of bit progression in a well being drilled. Because of this definition, the pilot tool is located in front of the expanding tool and the front face of the pilot tool is the face of it which faces the face of size.
  • bit according to the invention is of the type described in US 5,678,644.
  • the pilot tool includes a body of revolution provided with sharp elements.
  • the body of revolution comprises an axial core whose rear portion is arranged to be attached to a drill string coupled to a motor. Fixing the core to the drill string is usually performed via a threaded end formed on the rear face of the core.
  • a plurality of radial blades are approximately evenly distributed around the periphery of the core and carry the cutting elements.
  • the constitutive material of the core and blades is not critical for the definition of the invention. It can be steel, tungsten carbide or abrasive diamond impregnated material.
  • the cutting elements are not critical for the definition of the invention and may be any cutting elements commonly used in rotary bits. They may in particular be PDC cutting elements or infiltrated abrasive elements.
  • the cutting elements PDC (abbreviation of the English expression "Polycrystalline Diamond Compacts”) are well known in the sector of mining drilling. They comprise a polycrystalline diamond pellet on a cemented tungsten carbide substrate and are usually obtained by compressing a mixed diamond and cobalt powder on the tungsten carbide substrate.
  • the infiltrated abrasive elements are also well known in mining drilling technique and are usually obtained by mixing a diamond powder (optionally added with a metal carbide powder, for example tungsten carbide) with a powder of a fusible binder (for example). a Cu-Mn solder) and subjecting the mixture thus produced to compacting followed by sintering. Information on this technique is available in US 2002 / 0125048A1.
  • the expanding tool is offset laterally relative to the pilot tool (transversely to the axis of the pilot tool), so that a portion of its lateral peripheral surface is projecting from the peripheral surface of the pilot tool. pilot tool.
  • the peripheral surface of the pilot tool is, by definition, the surface of it that faces the wall of the well being drilled.
  • the peripheral surface of the expanding tool is the surface thereof, which faces the wall of the well during drilling.
  • the aforesaid portion projecting from the peripheral surface of the expanding tool is moved away from the axis of rotation of the bit by a distance greater than the maximum radius of the pilot tool (the axis of rotation of the bit being coincident with the axis of symmetry of the pilot tool). Subsequently, the aforesaid portion of the peripheral surface of the expanding tool will be designated 'enlarged part'.
  • the expanding tool is located behind the pilot tool. It has, on its enlarged part above, sharp elements.
  • the constituent material of the expanding tool, its profile and the cutting elements that equip it are not critical for the definition of the invention. It is generally preferred that the expanding tool comprises a core and radial blades in its enlarged portion, said blades carrying the cutting elements.
  • the core and blades may be steel, the cutting elements being PDC cutting elements.
  • the expanding tool and the pilot tool form a rigid composite assembly, substantially indeformable.
  • Both of these tools may include a single tool body carrying the cutting elements.
  • they may be formed of the indeformable assembly of two separate tool bodies (a body for the pilot tool and a body for the expanding tool).
  • the core and the blades of the pilot tool and the expanding tool are of steel and that their respective cutting elements are PDC cutting elements.
  • a portion of the PDC cutting elements may be replaced by diamond abrasive elements infiltrated.
  • the pilot tool and at least the enlarged portion of the expanding tool may be of infiltrated metal carbide, as is well known in the art of oil drilling tools.
  • the blades of the pilot tool extend on the lateral face of the tool body.
  • the blades of the pilot tool extend on the front face thereof, while leaving there a central axial zone, lacking blades and cutting elements. This results in the formation of an axial core during drilling.
  • said central axial zone of the pilot tool is in communication with a cavity located between two blades of the pilot tool.
  • This cavity serves to ensure the evacuation of the core to the periphery of the bit, then in the annular zone defined behind the bit, between the drill string and the wall of the well being drilled.
  • said cavity is delimited by two lateral surfaces and a clearance surface located at a distance from the front face of the tool. These two lateral surfaces can advantageously be two successive blades of the pilot tool. Additional information concerning the two characteristics of the invention defined above are accessible in document WO 2008/149240 (TOTAL SA).
  • the pilot tool comprises a device for breaking the core.
  • This breaking device has the function of breaking the core at regular intervals so as to obtain the most regular fragments possible.
  • the rupture device may for example comprise an abrasion-resistant pellet disposed in the aforementioned cavity of the pilot tool. This pellet may for example be a PDC cutting element or a pellet into an infiltrated abrasive element.
  • the core stabilizes the bit, exerting a counter-reaction to the lateral forces resulting from the dissymmetry of the expanding tool.
  • the core thus opposes a lateral deviation of the pilot tool.
  • the diameter of the aforementioned central zone of the pilot tool determines the diameter of the core. It must be calculated so that the core base withstands the lateral forces generated by the expanding tool during normal use of the bit and prevents lateral movement of the pilot tool. The selection of this diameter will depend on various parameters, among which include the dimensions of the bit, the type of cutting elements that equip it and the geological nature of the rock in which the well is drilled. (illustrative, non-exhaustive list). It must be determined in each particular case by those skilled in the art.
  • a portion of the peripheral surface of the expanding tool is radially recessed relative to the peripheral surface of the pilot tool; in this embodiment, the cavity of the pilot tool, used for the removal of the core, opens into this recessed portion of the expanding tool. This embodiment facilitates the removal of carrot debris and their transfer behind the bit.
  • the blades of the pilot tool are spiral. This embodiment of the invention facilitates the removal of debris from the core.
  • the expanding tool comprises blades, which are spiral and arranged in the extension of the blades of the pilot tool. This variant of the invention improves the removal of debris from the core behind the bit.
  • the drill bit further comprises, in well known manner in known drill bits, drilling mud feed channels. These channels open through the front face of the pilot tool, between its blades and they communicate with an axial channel opening into an internal conduit of the drill string.
  • drilling mud feed channels open through the front face of the pilot tool, between its blades and they communicate with an axial channel opening into an internal conduit of the drill string.
  • the drill bit according to the invention takes advantage of the fact that it combines an expanding tool and a core forming area.
  • the widening tool also makes it possible to produce large-diameter cores, which has the advantageous consequence of allowing greater drilling speeds and better geological analysis of the rock.
  • the drill bit according to the invention finds applications for drilling all types of wells for various applications. It is especially suitable for drilling artesian wells or deep wells in coal, ore, oil or gas deposits.
  • the drill bit according to the invention finds a particularly advantageous application for deepening pre-existing wells and in particular drilling in mortar plugs at the bottom thereof.
  • a trephine is selected which is introduced substantially exactly into the pre-existing well (usually cased).
  • the overall diameter of the bit enlarging tool is substantially equal to the diameter of the well.
  • the diameter of the aforementioned central zone of the pilot tool is at least equal to the difference between the overall diameter of the expanding tool and the diameter of the pilot tool.
  • the overall diameter of the expanding tool is, by definition, its largest dimension transverse to the axis of rotation of the pilot tool.
  • the invention therefore also relates to a method for deepening pre-existing wells implementing a bi-center bit according to the invention.
  • the invention particularly relates to such a method in which the radius of the central zone of the bit pilot tool is at least equal to the difference between the radius of the well and the radius of the pilot tool.
  • Figure 1 is an elevational view of an embodiment of the bit according to the invention.
  • Figure 2 is a front view of the bit of Figure 1;
  • Figure 3 is an elevational view of another embodiment of the bit according to the invention;
  • Figure 4 is a front view of the bit of Figure 3;
  • Figure 5 shows a bi-center drill bit in a well being deepened
  • Figure 6 is a front view of a particular embodiment of the bit according to the invention.
  • the bit shown in FIGS. 1 and 2 associates, on a unitary body, a pilot tool 1 and a finishing tool 2.
  • the pilot tool 1 is of revolution. It comprises an axial core 3 made of steel and radial blades 4 made of steel.
  • the radial blades 4 carry cutting elements 5 at their periphery.
  • the cutting elements 5 are advantageously cutting elements in PDC.
  • the expanding tool 2 comprises a core 6 made of steel, extending the core 3 of the pilot tool 1.
  • the core 6 carries radial blades 7 of steel on a part of its periphery, the remaining part 9 of its periphery being in the extension of the core 3 of the pilot tool 1.
  • the radial blades 7 carry cutting elements 8 PDC.
  • the blades 7 of the expanding tool are offset laterally relative to the pilot tool 1, so that their cutting elements 8 project from the peripheral surface of the pilot tool 1.
  • the portion 9 of the expanding tool 2 is set back relative to the periphery of the pilot tool 1.
  • the core 6 is extended by a threaded end 17 to attach it to the drill string, not shown.
  • the drilling mud supply channels 16 open out between the blades (7) of the drill pipe. widening tool 2.
  • the blades 4 of the pilot tool are interrupted in the anterior central area 11 of this tool.
  • This central zone 11 is centered on the axis of the bit (coincides with the axis of the pilot tool), so that, during the drilling of the well, a cylindrical rock core 12 is formed.
  • the pilot tool 1 further comprises a cavity 13 for the discharge of the core 12. This cavity 13 is delimited between two blades 4 and an inclined clearance surface 14, which opens in front of the portion 9 of the core 6 of the tool expander 2.
  • the bit is rotated in the direction of the arrow X ( Figure 2) and is moved axially in the direction of the arrow Y ( Figure 1) through a rock formation.
  • the pilot tool 1 digs the well that the expanding tool then widens.
  • Carrot 12 which is formed in the anterior central zone 11 of the pilot tool 1 keeps the bit assembly in the axis of the well being excavated, despite the lateral forces generated by the expanding tool 2.
  • the core 12 is deflected laterally on the clearance surface 14 of the cavity 13 where it breaks and its debris 15 are discharged to the mouth of the well by the drilling fluid.
  • a pellet (not shown) resistant to abrasion is disposed in the cavity 13, to break the core 12 as it is formed. This pellet may for example be a PDC pellet.
  • the blades 4 of the pilot tool 1 are spiral.
  • the radial blades 7 of the expanding tool 2 are rectilinear. Alternatively, they could be spiral in the same direction as the blades 4 of the pilot tool 1.
  • FIG. 5 a preexisting well has been schematized, into which a bi-center bit has been introduced, in order to extend said well.
  • the well shown in axial section, is cased with a metal tube 18.
  • the bit is dimensioned and positioned so that the overall diameter of its expanding tool 2 is substantially equal to the diameter of the well.
  • the bit being thus positioned in the well, its axis 19 (axis of symmetry of the pilot tool and the threaded end 17) is offset relative to the axis 20 of the well.
  • the bit is subjected to an epicyclic movement.
  • the central zone 11 of the pilot tool is delimited by a circle which is centered on the axis 19 and whose radius is equal to the distance separating the two axes 19 and 20. Its radius is substantially equal to the difference between the radius of the well 18 and the radius of the pilot tool 1.
  • FIG. 6 shows the circular central zone 11 of the bit of FIG. 5. This central zone 11 is delimited between the axis 19 of the bit and the axis 20 of the well 18.

Abstract

Two-centre rotary boring bit for boring wells, comprising, on the one hand, a pilot tool (1) comprising a body of revolution with an axial core (3) and radial blades (4) bearing cutting elements (5) and, on the other hand, an enlarging tool (2) fitted behind the pilot tool and laterally offset therefrom, the pilot tool having, on its front face, a central region (11) that has no cutting elements in order to allow the creation of a core sample (12), said central region being in communication with a cavity (13) situated between two blades (4) of the pilot tool (1) and serving to remove the core sample toward the periphery of the boring bit.

Description

Trépan rotatif bi-centre et procédé pour  Bi-center rotary bit and method for
l'approfondissement d'un puits préexistant  the deepening of a pre-existing well
Domaine de l'invention Field of the invention
L'invention se rapporte aux trépans rotatifs, spécialement aux trépans destinés au forage de puits dans des gisements de fluides comme du pétrole ou du gaz naturel .  The invention relates to rotary bits, especially to bits for drilling wells in fluid deposits such as oil or natural gas.
L'invention concerne plus particulièrement un trépan rotatif du type bi-centre comprenant un outil pilote suivi d'un outil élargisseur.  The invention more particularly relates to a rotary bit of the bi-center type comprising a pilot tool followed by a widening tool.
Etat de la technique  State of the art
Les trépans sont des outils de forage destinés à être fixés à l'extrémité d'un train de tiges pour forer un puits jusqu'à un gisement souterrain utile, tel qu'un gisement de pétrole, de gaz, d'eau, de minerai ou de houille. Le train de tiges est supporté par une tour située en surface. Une boue de forage est généralement injectée à l'intérieur du train de tiges pour ressortir par le trépan et remonter jusqu'à la surface, par l'espace annulaire formé entre le train de tiges et le puits en cours de forage. La boue de forage a pour fonction de refroidir le trépan et d'évacuer les débris du forage jusqu'à la surface.  Drill bits are drill tools that are attached to the end of a drill string to drill a well to a useful underground deposit, such as a deposit of oil, gas, water, ore. or coal. The drill string is supported by a tower located on the surface. A drilling mud is generally injected into the drill string to exit through the bit and back to the surface by the annular space formed between the drill string and the well being drilled. The function of the drilling mud is to cool the drill bit and to remove debris from the borehole to the surface.
Les trépans rotatifs du type bi-centre sont bien connus en technique de forage, où on les utilise pour le forage de puits de grand diamètre ou pour approfondir tout en élargissant des puits préexistants. Ces trépans connus, décrits notamment dans les documents US- 5 678 644 et US 2002/0104688 comprennent un outil pilote, suivi d'un outil élargisseur, ces deux outils formant un ensemble unitaire rigide. L'outil pilote comprend un corps de révolution avec un noyau axial portant, à une extrémité, des lames radiales et frontales munies d'éléments tranchants et, à l'autre extrémité, un embout fileté pour le fixer au train de tiges. L'outil élargisseur est intercalé entre l'outil pilote et l'embout fileté. Il comprend un corps muni d'éléments tranchants sur une portion seulement de sa périphérie, de sorte qu'il est asymétrique, ses éléments tranchants agissant à la manière d'une fraise pour élargir le puits en cours de forage, derrière l'outil pilote. Bi-center rotary bits are well known in drilling technology, where they are used for drilling large diameter wells or for deepening while widening pre-existing wells. These known drill bits, described in particular in US 5 678 644 and US 2002/0104688 comprise a pilot tool, followed by an expanding tool, these two tools forming a rigid unitary assembly. The pilot tool comprises a body of revolution with an axial core carrying, at one end, radial and frontal blades provided with cutting elements and, at the other end, a threaded end to fix it to the drill string. The expanding tool is inserted between the pilot tool and the threaded end. It includes a body with cutting elements on only a portion of its periphery, so that it is asymmetrical, its cutting elements acting in the manner of a bur to expand the well being drilled, behind the pilot tool .
Dans les trépans bi-centre connus, décrits ci- dessus, le profil asymétrique de l'outil élargisseur a pour effet de déséquilibrer le trépan pendant le forage. Cette particularité constitue un désavantage des trépans bi-centre connus, en nuisant à la qualité et la précision. Elle soumet en outre le trépan à des efforts parasites, susceptibles de l'endommager prématurément.  In known bi-center bits, described above, the asymmetrical profile of the expanding tool has the effect of unbalancing the bit during drilling. This feature is a disadvantage of known bi-center bits, affecting quality and accuracy. It also subjects the bit to parasitic forces, which can damage it prematurely.
Lorsque ces trépans bi-centre connus sont utilisés pour approfondir des puits préexistants, ils y sont normalement soumis à un mouvement épicycloïdal jusqu'à ce qu'ils sortent du tubage. Dès que l'outil pilote du trépan sort du tubage, le trépan reprend le forage normal du puits, avec élargissement. Sous l'effet du mouvement épicycloïdal, les éléments tranchants situés dans la partie centrale de l'outil pilote subissent un mouvement de précession et tournent à l'envers, ce qui est dommageable pour ces éléments coupants lorsqu'ils entrent en contact avec le fond du puits . Résumé de l'invention When these known bi-center drill bits are used to deepen pre-existing wells, they are normally subjected to epicyclic movement until they come out of the casing. As soon as the pilot tool of the bit comes out of the casing, the bit resumes normal drilling of the well, with enlargement. Under the effect of the epicyclic movement, the cutting elements located in the central part of the pilot tool undergo a precession movement and turn upside down, which is harmful for these cutting elements when they come into contact with the bottom. of Wells . Summary of the invention
L'invention vise à remédier aux désavantages précités des trépans connus décrits plus haut.  The invention aims to overcome the aforementioned disadvantages of known drills described above.
L'invention vise plus particulièrement à fournir un trépan rotatif du type bi-centre, d'une conception nouvelle, susceptible d'éviter un déséquilibrage du trépan.  The object of the invention is more particularly to provide a rotary bit of the bi-center type, of a new design, capable of preventing unbalance of the bit.
Un autre objectif de l'invention consiste à fournir un trépan du type bi -centre dont l'efficacité est améliorée et qui permette une grande précision du forage.  Another object of the invention is to provide a bi-center type drill bit whose efficiency is improved and which allows a high precision drilling.
Un objectif supplémentaire de l'invention est d'améliorer le rendement des trépans rotatifs du type bi- centre, en permettant des vitesses de forage plus élevées.  A further object of the invention is to improve the efficiency of the bi-center type rotary bits by allowing higher drilling speeds.
L'invention a aussi pour objectif de renforcer la précision de l'analyse géologique du massif en cours de forage .  The invention also aims to enhance the accuracy of the geological analysis of the massif during drilling.
Un objectif supplémentaire de l'invention est de fournir un trépan bi-centre qui soit spécialement adapté à une utilisation dans un puits préexistant pour l'approfondir, spécialement un puits dont le diamètre est sensiblement égal à la plus grande dimension transversale de l'outil élargisseur du trépan.  A further object of the invention is to provide a bi-center bit which is specially adapted for use in a pre-existing well to deepen it, especially a well whose diameter is substantially equal to the greatest transverse dimension of the tool. bit enlarger.
En conséquence, l'invention concerne un trépan rotatif bi-centre pour le forage de puits, comprenant, d'une part, un outil pilote comprenant un corps de révolution avec un noyau axial et des lames radiales portant des éléments tranchants et, d'autre part, un outil élargisseur disposé derrière l'outil pilote et décalé latéralement par rapport à celui-ci ; selon l'invention, le trépan se caractérise en ce que la face avant de l'outil pilote présente une zone centrale axiale qui est dépourvue d'éléments tranchants pour permettre la formation d'une carotte axiale, ladite zone centrale étant en communication avec une cavité située entre deux lames de l'outil pilote et servant à l'évacuation de la carotte vers la périphérie du trépan. Accordingly, the invention relates to a bi-center rotary bit for drilling wells, comprising, on the one hand, a pilot tool comprising a body of revolution with an axial core and radial blades carrying cutting elements and, on the other hand, an expanding tool placed behind the pilot tool and offset laterally thereto; according to the invention, the bit is characterized in that the front face of the pilot tool has an axial central zone which is devoid of cutting elements to allow the formation of an axial core, said central zone being in communication with a cavity located between two blades of the pilot tool and used to evacuate the core towards the periphery of the bit.
Description détaillée de l ' invention  Detailed description of the invention
Dans le présent mémoire, les vocables 'avant' , In this memo, the words 'before',
'arrière' , 'devant' , 'derrière' , 'antérieur' et 'postérieur' sont définis par rapport au sens de la progression du trépan dans un puits en cours de forage. Du fait de cette définition, l'outil pilote est situé devant l'outil élargisseur et la face avant de l'outil pilote est la face de celui-ci qui fait face au front de taille . 'back', 'front', 'behind', 'front' and 'posterior' are defined with respect to the direction of bit progression in a well being drilled. Because of this definition, the pilot tool is located in front of the expanding tool and the front face of the pilot tool is the face of it which faces the face of size.
Dans sa conception générale, le trépan selon l'invention est du type de celui décrit dans le document US 5 678 644.  In its general design, the bit according to the invention is of the type described in US 5,678,644.
L'outil pilote comprend un corps de révolution muni d'éléments tranchants. Le corps de révolution comprend un noyau axial dont la partie arrière est agencée pour pouvoir être fixée à un train de tiges couplé à un moteur. La fixation du noyau au train de tiges est habituellement réalisée par l'intermédiaire d'un embout fileté ménagé sur la face arrière du noyau.  The pilot tool includes a body of revolution provided with sharp elements. The body of revolution comprises an axial core whose rear portion is arranged to be attached to a drill string coupled to a motor. Fixing the core to the drill string is usually performed via a threaded end formed on the rear face of the core.
Une pluralité de lames radiales sont approximativement uniformément réparties à la périphérie du noyau et elles portent les éléments tranchants. La matière constitutive du noyau et des lames n'est pas critique pour la définition de l'invention. Elle peut être de l'acier, du carbure de tungstène ou une matière abrasive en diamants imprégnés. A plurality of radial blades are approximately evenly distributed around the periphery of the core and carry the cutting elements. The constitutive material of the core and blades is not critical for the definition of the invention. It can be steel, tungsten carbide or abrasive diamond impregnated material.
Les éléments tranchants ne sont pas critiques pour la définition de l'invention et peuvent être tous éléments tranchants communément utilisés dans les trépans rotatifs. Ils peuvent notamment être des éléments coupants PDC ou des éléments abrasifs infiltrés. Les éléments coupants PDC (abréviation de l'expression anglo- saxonne « Polycrystalline Diamond Compacts ») sont bien connus dans le secteur du forage minier. Ils comprennent une pastille en diamant polycristallin sur un substrat en carbure de tungstène cémenté et ils sont habituellement obtenus en comprimant une poudre mixte de diamant et de cobalt sur le substrat en carbure de tungstène . Les éléments abrasifs infiltrés sont également bien connus en technique de forage minier et sont usuellement obtenus en mélangeant une poudre diamantée (éventuellement additionnée d'une poudre de carbure métallique, par exemple du carbure de tungstène) avec une poudre d'un liant fusible (par exemple une brasure Cu-Mn) et en soumettant le mélange ainsi réalisé à un compactage suivi d'un frittage. Des informations sur cette technique sont accessibles dans le document US 2002/0125048A1.  The cutting elements are not critical for the definition of the invention and may be any cutting elements commonly used in rotary bits. They may in particular be PDC cutting elements or infiltrated abrasive elements. The cutting elements PDC (abbreviation of the English expression "Polycrystalline Diamond Compacts") are well known in the sector of mining drilling. They comprise a polycrystalline diamond pellet on a cemented tungsten carbide substrate and are usually obtained by compressing a mixed diamond and cobalt powder on the tungsten carbide substrate. The infiltrated abrasive elements are also well known in mining drilling technique and are usually obtained by mixing a diamond powder (optionally added with a metal carbide powder, for example tungsten carbide) with a powder of a fusible binder (for example). a Cu-Mn solder) and subjecting the mixture thus produced to compacting followed by sintering. Information on this technique is available in US 2002 / 0125048A1.
L'outil élargisseur est décalé latéralement par rapport à l'outil pilote (transversalement à l'axe de l'outil pilote), de telle sorte qu'une partie de sa surface périphérique latérale soit en saillie par rapport à la surface périphérique de l'outil pilote. La surface périphérique de l'outil pilote est, par définition, la surface de celui-ci qui fait face à la paroi du puits en cours de forage. De manière similaire, la surface périphérique de l'outil élargisseur est la surface de celui-ci, qui fait face à la paroi du puits en cours de forage. Dans le trépan selon l'invention, la partie précitée en saillie de la surface périphérique de l'outil élargisseur est éloignée de l'axe de rotation du trépan d'une distance supérieure au rayon maximum de l'outil pilote (l'axe de rotation du trépan étant confondu avec l'axe de symétrie de l'outil pilote) . Par la suite, la partie susdite de la surface périphérique de l'outil élargisseur sera désignée 'partie élargie' . The expanding tool is offset laterally relative to the pilot tool (transversely to the axis of the pilot tool), so that a portion of its lateral peripheral surface is projecting from the peripheral surface of the pilot tool. pilot tool. The peripheral surface of the pilot tool is, by definition, the surface of it that faces the wall of the well being drilled. Similarly, the peripheral surface of the expanding tool is the surface thereof, which faces the wall of the well during drilling. In the bit according to the invention, the aforesaid portion projecting from the peripheral surface of the expanding tool is moved away from the axis of rotation of the bit by a distance greater than the maximum radius of the pilot tool (the axis of rotation of the bit being coincident with the axis of symmetry of the pilot tool). Subsequently, the aforesaid portion of the peripheral surface of the expanding tool will be designated 'enlarged part'.
L'outil élargisseur est situé derrière l'outil pilote. Il porte, sur sa partie élargie précitée, des éléments tranchants. La matière constitutive de l'outil élargisseur, son profil et les éléments tranchants qui l' équipent ne sont pas critiques pour la définition de l'invention. On préfère généralement que l'outil élargisseur comprenne un noyau et des lames radiales dans sa partie élargie, lesdites lames portant les éléments tranchants. Dans cette forme de réalisation particulière de l'invention, le noyau et les lames peuvent être en acier, les éléments tranchants étant des éléments coupants en PDC.  The expanding tool is located behind the pilot tool. It has, on its enlarged part above, sharp elements. The constituent material of the expanding tool, its profile and the cutting elements that equip it are not critical for the definition of the invention. It is generally preferred that the expanding tool comprises a core and radial blades in its enlarged portion, said blades carrying the cutting elements. In this particular embodiment of the invention, the core and blades may be steel, the cutting elements being PDC cutting elements.
L'outil élargisseur et l'outil pilote forment un ensemble composite rigide, sensiblement indéformable. Ces deux outils peuvent comprendre un corps d'outil unique, portant les éléments tranchants. En variante, ils peuvent être formés de l'assemblage indéformable de deux corps d'outils distincts (un corps pour l'outil pilote et un corps pour l'outil élargisseur). On préfère, selon l'invention, que le noyau et les lames de l'outil pilote et de l'outil élargisseur soient en acier et que leurs éléments tranchants respectifs soient des éléments coupants PDC. En variante, une partie des éléments coupants PDC peuvent être remplacés par des éléments abrasifs en diamants infiltrés.The expanding tool and the pilot tool form a rigid composite assembly, substantially indeformable. Both of these tools may include a single tool body carrying the cutting elements. Alternatively, they may be formed of the indeformable assembly of two separate tool bodies (a body for the pilot tool and a body for the expanding tool). According to the invention, it is preferred that the core and the blades of the pilot tool and the expanding tool are of steel and that their respective cutting elements are PDC cutting elements. Alternatively, a portion of the PDC cutting elements may be replaced by diamond abrasive elements infiltrated.
Dans une forme de réalisation modifiée, l'outil pilote et au moins la partie élargie de l'outil élargisseur peuvent être en carbure métallique infiltré, comme il est bien connu dans la technique des outils de forage pétrolier. In a modified embodiment, the pilot tool and at least the enlarged portion of the expanding tool may be of infiltrated metal carbide, as is well known in the art of oil drilling tools.
Dans le trépan selon l'invention, les lames de l'outil pilote s'étendent sur la face latérale du corps d' outil .  In the bit according to the invention, the blades of the pilot tool extend on the lateral face of the tool body.
Selon une première caractéristique de l'invention, les lames de l'outil pilote se prolongent sur la face avant de celui-ci, tout en y laissant une zone centrale axiale, démunie de lames et d'éléments tranchants. Il s'ensuit la formation d'une carotte axiale au cours du forage .  According to a first characteristic of the invention, the blades of the pilot tool extend on the front face thereof, while leaving there a central axial zone, lacking blades and cutting elements. This results in the formation of an axial core during drilling.
Selon une seconde caractéristique de l'invention, ladite zone centrale axiale de l'outil pilote est en communication avec une cavité située entre deux lames de l'outil pilote. Cette cavité a pour fonction d'assurer l'évacuation de la carotte vers la périphérie du trépan, puis dans la zone annulaire délimitée derrière le trépan, entre le train de tiges et la paroi du puits en cours de forage. A cet effet, ladite cavité est délimitée par deux surfaces latérales et une surface de dégagement située en recul par rapport à la face avant de l'outil. Ces deux surfaces latérales peuvent, avec avantage, être deux lames successives de l'outil pilote. Des informations complémentaires concernant les deux caractéristiques de l'invention définies plus haut sont accessibles dans le document WO 2008/149240 (TOTAL S.A. ) . According to a second characteristic of the invention, said central axial zone of the pilot tool is in communication with a cavity located between two blades of the pilot tool. This cavity serves to ensure the evacuation of the core to the periphery of the bit, then in the annular zone defined behind the bit, between the drill string and the wall of the well being drilled. For this purpose, said cavity is delimited by two lateral surfaces and a clearance surface located at a distance from the front face of the tool. These two lateral surfaces can advantageously be two successive blades of the pilot tool. Additional information concerning the two characteristics of the invention defined above are accessible in document WO 2008/149240 (TOTAL SA).
II est souhaitable, selon une forme de réalisation particulière de l'invention, que l'outil pilote comprenne un dispositif de rupture de la carotte. Ce dispositif de rupture a pour fonction de briser la carotte à intervalles réguliers de manière à obtenir des fragments les plus réguliers possible. Dans cette forme de réalisation de l'invention, le dispositif de rupture peut par exemple comprendre une pastille résistant à l'abrasion, disposée dans la cavité précitée de l'outil pilote. Cette pastille peut par exemple être un élément coupant PDC ou une pastille en un élément abrasif infiltré .  It is desirable, according to a particular embodiment of the invention, that the pilot tool comprises a device for breaking the core. This breaking device has the function of breaking the core at regular intervals so as to obtain the most regular fragments possible. In this embodiment of the invention, the rupture device may for example comprise an abrasion-resistant pellet disposed in the aforementioned cavity of the pilot tool. This pellet may for example be a PDC cutting element or a pellet into an infiltrated abrasive element.
Dans le trépan selon l'invention, la carotte stabilise le trépan, en exerçant une contre-réaction aux efforts latéraux résultant de la dissymétrie de l'outil élargisseur. La carotte s'oppose ainsi à une déviation latérale de l'outil pilote. In the bit according to the invention, the core stabilizes the bit, exerting a counter-reaction to the lateral forces resulting from the dissymmetry of the expanding tool. The core thus opposes a lateral deviation of the pilot tool.
Le diamètre de la zone centrale précitée de l'outil pilote conditionne le diamètre de la carotte. Il doit être calculé pour que la base de la carotte résiste aux efforts latéraux générés par l'outil élargisseur pendant une utilisation normale du trépan et empêche un déplacement latéral de l'outil pilote. La sélection de ce diamètre va dépendre de divers paramètres, parmi lesquels figurent notamment les dimensions du trépan, le type d'éléments tranchants qui l' équipent et la nature géologique de la roche dans laquelle le puits est foré (liste exemplative, non exhaustive) . Il doit être déterminé dans chaque cas particulier par l'homme du métier . The diameter of the aforementioned central zone of the pilot tool determines the diameter of the core. It must be calculated so that the core base withstands the lateral forces generated by the expanding tool during normal use of the bit and prevents lateral movement of the pilot tool. The selection of this diameter will depend on various parameters, among which include the dimensions of the bit, the type of cutting elements that equip it and the geological nature of the rock in which the well is drilled. (illustrative, non-exhaustive list). It must be determined in each particular case by those skilled in the art.
Dans une forme de réalisation avantageuse du trépan selon l'invention, une partie de la surface périphérique de l'outil élargisseur est radialement en retrait par rapport à la surface périphérique de l'outil pilote ; dans cette forme de réalisation, la cavité de l'outil pilote, servant à l'évacuation de la carotte, débouche dans cette partie en retrait de l'outil élargisseur. Cette forme de réalisation facilite l'évacuation des débris de la carotte et leur transfert derrière le trépan.  In an advantageous embodiment of the bit according to the invention, a portion of the peripheral surface of the expanding tool is radially recessed relative to the peripheral surface of the pilot tool; in this embodiment, the cavity of the pilot tool, used for the removal of the core, opens into this recessed portion of the expanding tool. This embodiment facilitates the removal of carrot debris and their transfer behind the bit.
Dans une autre forme de réalisation avantageuse de l'invention, les lames de l'outil pilote sont spiralées. Cette forme de réalisation de l'invention facilite l'évacuation des débris de la carotte. Dans une variante préférée de cette forme de réalisation de l'invention, l'outil élargisseur comprend des lames, qui sont spiralées et disposées dans le prolongement des lames de l'outil pilote. Cette variante de l'invention améliore l'évacuation des débris de la carotte derrière le trépan.  In another advantageous embodiment of the invention, the blades of the pilot tool are spiral. This embodiment of the invention facilitates the removal of debris from the core. In a preferred variant of this embodiment of the invention, the expanding tool comprises blades, which are spiral and arranged in the extension of the blades of the pilot tool. This variant of the invention improves the removal of debris from the core behind the bit.
Dans une forme de réalisation supplémentaire de l'invention, le trépan comprend en outre, de manière bien connue dans les trépans connus, de canaux d'alimentation en boue de forage . Ces canaux débouchent à travers la face avant de l'outil pilote, entre ses lames et ils communiquent avec un canal axial débouchant dans un conduit interne du train de tiges. Comparé aux trépans bi-centre connus, le trépan bi- centre selon l'invention présente une meilleure stabilité, une efficacité et un rendement supérieurs et une plus grande précision dans une opération de forage. La récupération des débris de la carotte permet par ailleurs une analyse minéralogique plus précise des couches géologiques traversées par le puits . In a further embodiment of the invention, the drill bit further comprises, in well known manner in known drill bits, drilling mud feed channels. These channels open through the front face of the pilot tool, between its blades and they communicate with an axial channel opening into an internal conduit of the drill string. Compared to known bi-center bits, the bi-center bit according to the invention has better stability, higher efficiency and efficiency and greater accuracy in a drilling operation. The recovery of carrot debris also allows a more precise mineralogical analysis of the geological layers traversed by the well.
Le trépan selon l'invention tire un avantage important du fait qu'il combine un outil élargisseur et une zone de formation d'une carotte. En permettant le forage de puits de grands diamètres, l'outil élargisseur permet par la même occasion de réaliser des carottes de grand diamètre, ce qui a pour conséquence avantageuse de permettre de plus grandes vitesses de forage et une meilleure analyse géologique de la roche.  The drill bit according to the invention takes advantage of the fact that it combines an expanding tool and a core forming area. By allowing large-diameter wells to be drilled, the widening tool also makes it possible to produce large-diameter cores, which has the advantageous consequence of allowing greater drilling speeds and better geological analysis of the rock.
Le trépan selon l'invention trouve des applications pour le forage de tous types de puits pour diverses applications. Il est tout spécialement adapté au forage de puits artésiens ou de puits profonds dans des gisements de houille, de minerais, de pétrole ou de gaz.  The drill bit according to the invention finds applications for drilling all types of wells for various applications. It is especially suitable for drilling artesian wells or deep wells in coal, ore, oil or gas deposits.
Le trépan selon l'invention trouve une application spécialement avantageuse pour approfondir des puits préexistants et notamment forer dans des bouchons de mortier au fond de ceux-ci. Dans cette application de l'invention, on sélectionne un trépan qui s'introduit sensiblement exactement dans le puits préexistant (habituellement tubé) . Le diamètre hors tout de l'outil élargisseur du trépan est sensiblement égal au diamètre du puits . Dans une forme de réalisation avantageuse de l'invention, spécialement adaptée à cette application, le diamètre de la zone centrale précitée de l'outil pilote est au moins égal à la différence entre le diamètre hors tout de l'outil élargisseur et le diamètre de l'outil pilote. Le diamètre hors tout de l'outil élargisseur est, par définition, sa plus grande dimension transversale à l'axe de rotation de l'outil pilote. Lorsqu'un trépan selon cette forme de réalisation de l'invention est utilisé pour approfondir un puits préexistant, aucun de ses éléments tranchants ne subit un mouvement de précession. Dans cette forme de réalisation de l'invention, il convient de laisser, autour de ladite zone centrale, une couronne suffisante d'éléments tranchants pour permettre de forer à travers le fond du puits . The drill bit according to the invention finds a particularly advantageous application for deepening pre-existing wells and in particular drilling in mortar plugs at the bottom thereof. In this application of the invention, a trephine is selected which is introduced substantially exactly into the pre-existing well (usually cased). The overall diameter of the bit enlarging tool is substantially equal to the diameter of the well. In an advantageous embodiment of the invention, especially adapted to this application, the diameter of the aforementioned central zone of the pilot tool is at least equal to the difference between the overall diameter of the expanding tool and the diameter of the pilot tool. The overall diameter of the expanding tool is, by definition, its largest dimension transverse to the axis of rotation of the pilot tool. When a drill bit according to this embodiment of the invention is used to deepen a pre-existing well, none of its cutting elements undergoes a precession. In this embodiment of the invention, it is appropriate to leave, around said central zone, a sufficient crown of cutting elements to allow drilling through the bottom of the well.
L'invention concerne dès lors également un procédé pour l'approfondissement de puits préexistants mettant en œuvre un trépan bi-centre conforme à l'invention. L' invention concerne tout spécialement un tel procédé dans lequel le rayon de la zone centrale de l'outil pilote du trépan est au moins égal à la différence entre le rayon du puits et le rayon de l'outil pilote.  The invention therefore also relates to a method for deepening pre-existing wells implementing a bi-center bit according to the invention. The invention particularly relates to such a method in which the radius of the central zone of the bit pilot tool is at least equal to the difference between the radius of the well and the radius of the pilot tool.
Brève description des figures Brief description of the figures
Des particularités et détails de l'invention vont apparaître au cours de la description suivante des figures annexées, qui représentent quelques formes de réalisation particulières de l'invention.  Features and details of the invention will become apparent from the following description of the accompanying figures, which show some particular embodiments of the invention.
La figure 1 est une vue en élévation d'une forme de réalisation du trépan selon l'invention ;  Figure 1 is an elevational view of an embodiment of the bit according to the invention;
La figure 2 est une vue de face du trépan de la figure 1 ; La figure 3 est une vue en élévation d'une autre forme de réalisation du trépan selon l'invention ; Figure 2 is a front view of the bit of Figure 1; Figure 3 is an elevational view of another embodiment of the bit according to the invention;
La figure 4 est une vue de face du trépan de la figure 3 ;  Figure 4 is a front view of the bit of Figure 3;
La figure 5 montre un trépan bi- centre dans un puits en cours d'approfondissement ; et  Figure 5 shows a bi-center drill bit in a well being deepened; and
La figure 6 est une vue de face d'une forme de réalisation particulière du trépan selon l'invention.  Figure 6 is a front view of a particular embodiment of the bit according to the invention.
Dans ces figures, des mêmes notations de référence désignent des éléments identiques.  In these figures, the same reference notations designate identical elements.
Description détaillée de modes de réalisation particuliers Detailed description of particular embodiments
Le trépan représenté aux figures 1 et 2 associe, sur un corps unitaire, un outil pilote 1 et un outil finisseur 2. The bit shown in FIGS. 1 and 2 associates, on a unitary body, a pilot tool 1 and a finishing tool 2.
L'outil pilote 1 est de révolution. Il comprend un noyau axial 3 en acier et des lames radiales 4 en acier. Les lames radiales 4 portent des éléments tranchants 5 à leur périphérie. Les éléments tranchants 5 sont avantageusement des éléments coupants en PDC.  The pilot tool 1 is of revolution. It comprises an axial core 3 made of steel and radial blades 4 made of steel. The radial blades 4 carry cutting elements 5 at their periphery. The cutting elements 5 are advantageously cutting elements in PDC.
L'outil élargisseur 2 comprend un noyau 6 en acier, prolongeant le noyau 3 de l'outil pilote 1. Le noyau 6 porte des lames radiales 7 en acier sur une partie de sa périphérie, la partie restante 9 de sa périphérie étant dans le prolongement du noyau 3 de l'outil pilote 1. Les lames radiales 7 portent des éléments tranchants 8 en PDC.  The expanding tool 2 comprises a core 6 made of steel, extending the core 3 of the pilot tool 1. The core 6 carries radial blades 7 of steel on a part of its periphery, the remaining part 9 of its periphery being in the extension of the core 3 of the pilot tool 1. The radial blades 7 carry cutting elements 8 PDC.
Les lames 7 de l'outil élargisseur sont décalées latéralement par rapport à l'outil pilote 1, de telle sorte que leurs éléments tranchants 8 sont en saillie par rapport à la surface périphérique de l'outil pilote 1. La partie 9 de l'outil élargisseur 2 est en retrait par rapport à la périphérie de l'outil pilote 1. The blades 7 of the expanding tool are offset laterally relative to the pilot tool 1, so that their cutting elements 8 project from the peripheral surface of the pilot tool 1. The portion 9 of the expanding tool 2 is set back relative to the periphery of the pilot tool 1.
Le noyau 6 est prolongé par un embout fileté 17 pour le fixer au train de tiges, non représenté.  The core 6 is extended by a threaded end 17 to attach it to the drill string, not shown.
Des canaux 10, servant à l'alimentation en boue de forage, débouchent à travers la face avant de l'outil pilote 1. De manière similaire, des canaux 16 d'alimentation en boue de forage débouchent entre les lames (7) de l'outil élargisseur 2.  Channels 10, serving to supply drilling mud, open through the front face of the pilot tool 1. Similarly, the drilling mud supply channels 16 open out between the blades (7) of the drill pipe. widening tool 2.
Conformément à l'invention, les lames 4 de l'outil pilote sont interrompues dans la zone centrale antérieure 11 de cet outil. Cette zone centrale 11 est centrée sur l'axe du trépan (confondu avec l'axe de l'outil pilote), de sorte que, pendant le forage du puits, il se forme une carotte rocheuse cylindrique 12.  According to the invention, the blades 4 of the pilot tool are interrupted in the anterior central area 11 of this tool. This central zone 11 is centered on the axis of the bit (coincides with the axis of the pilot tool), so that, during the drilling of the well, a cylindrical rock core 12 is formed.
L'outil pilote 1 comprend en outre une cavité 13 pour l'évacuation de la carotte 12. Cette cavité 13 est délimitée entre deux lames 4 et une surface de dégagement inclinée 14, qui débouche devant la partie 9 du noyau 6 de l'outil élargisseur 2.  The pilot tool 1 further comprises a cavity 13 for the discharge of the core 12. This cavity 13 is delimited between two blades 4 and an inclined clearance surface 14, which opens in front of the portion 9 of the core 6 of the tool expander 2.
Pour creuser un puits au moyen du trépan des figures 1 et 2, le trépan est mis en rotation dans le sens de la flèche X (figure 2) et il est déplacé axialement dans le sens de la flèche Y (figure 1) à travers une formation rocheuse. Au fur et à mesure qu'il s'enfonce dans la masse rocheuse, l'outil pilote 1 creuse le puits que l'outil élargisseur élargit ensuite. La carotte 12 qui se forme dans la zone centrale antérieure 11 de l'outil pilote 1 maintient l'ensemble du trépan dans l'axe du puits en cours de creusement, en dépit des forces latérales générées par l'outil élargisseur 2. Au fur et à mesure de la progression du trépan dans la formation rocheuse, la carotte 12 est déviée latéralement sur la surface de dégagement 14 de la cavité 13 où elle se rompt et ses débris 15 sont évacués vers l'embouchure du puits par le liquide de forage. Dans une variante de l'invention, une pastille (non représentée) résistant à l'abrasion est disposée dans la cavité 13 , pour rompre la carotte 12 au fur et à mesure de sa formation. Cette pastille peut par exemple être une pastille en PDC. To dig a well by means of the bit of Figures 1 and 2, the bit is rotated in the direction of the arrow X (Figure 2) and is moved axially in the direction of the arrow Y (Figure 1) through a rock formation. As it sinks into the rock mass, the pilot tool 1 digs the well that the expanding tool then widens. Carrot 12 which is formed in the anterior central zone 11 of the pilot tool 1 keeps the bit assembly in the axis of the well being excavated, despite the lateral forces generated by the expanding tool 2. As and when the progress of the bit in the rock formation, the core 12 is deflected laterally on the clearance surface 14 of the cavity 13 where it breaks and its debris 15 are discharged to the mouth of the well by the drilling fluid. In a variant of the invention, a pellet (not shown) resistant to abrasion is disposed in the cavity 13, to break the core 12 as it is formed. This pellet may for example be a PDC pellet.
Dans le trépan des figures 3 et 4 , les lames 4 de l'outil pilote 1 sont spiralées. Les lames radiales 7 de l'outil élargisseur 2 sont rectilignes. En variante, elles pourraient être spiralées dans le même sens que les lames 4 de l'outil pilote 1.  In the bit of Figures 3 and 4, the blades 4 of the pilot tool 1 are spiral. The radial blades 7 of the expanding tool 2 are rectilinear. Alternatively, they could be spiral in the same direction as the blades 4 of the pilot tool 1.
A la figure 5, on a schématisé un puits préexistant, dans lequel on a introduit un trépan bi-centre, dans le but de prolonger ledit puits. Le puits, montré en section axiale, est tubé d'un tube métallique 18. Le trépan est dimensionné et positionné de telle sorte que le diamètre hors tout de son outil élargisseur 2 soit sensiblement égal au diamètre du puits. Le trépan étant ainsi positionné dans le puits, son axe 19 (axe de symétrie de l'outil pilote et de l'embout fileté 17) est décalé par rapport à l'axe 20 du puits. Pendant l'approfondissement du puits, le trépan est soumis à un mouvement épicycloïdal . Selon l'invention, la zone centrale 11 de l'outil pilote est délimitée par un cercle qui est centré sur l'axe 19 et dont le rayon est égal à la distance séparant les deux axes 19 et 20. Son rayon est sensiblement égal à la différence entre le rayon du puits 18 et le rayon de l'outil pilote 1. In FIG. 5, a preexisting well has been schematized, into which a bi-center bit has been introduced, in order to extend said well. The well, shown in axial section, is cased with a metal tube 18. The bit is dimensioned and positioned so that the overall diameter of its expanding tool 2 is substantially equal to the diameter of the well. The bit being thus positioned in the well, its axis 19 (axis of symmetry of the pilot tool and the threaded end 17) is offset relative to the axis 20 of the well. During the deepening of the well, the bit is subjected to an epicyclic movement. According to the invention, the central zone 11 of the pilot tool is delimited by a circle which is centered on the axis 19 and whose radius is equal to the distance separating the two axes 19 and 20. Its radius is substantially equal to the difference between the radius of the well 18 and the radius of the pilot tool 1.
La figure 6 montre la zone centrale circulaire 11 du trépan de la figure 5. Cette zone centrale 11 est délimitée entre l'axe 19 du trépan et l'axe 20 du puits 18.  FIG. 6 shows the circular central zone 11 of the bit of FIG. 5. This central zone 11 is delimited between the axis 19 of the bit and the axis 20 of the well 18.

Claims

REVENDICATIONS
Trépan rotatif bi -centre pour le forage de puits, comprenant, d'une part, un outil pilote comprenant un corps de révolution avec un noyau axial et des lames radiales portant des éléments tranchants et, d'autre part, un outil élargisseur disposé derrière l'outil pilote et décalé latéralement par rapport à celui-ci, caractérisé en ce que la face avant de l'outil pilote (1) présente une zone centrale axiale (11) qui est dépourvue d'éléments tranchants (5) pour permettre la formation d'une carotte axiale (12), ladite zone centrale étant en communication avec une cavité (13) située entre deux lames (4) de l'outil pilote et servant à l'évacuation de la carotte vers la périphérie du trépan.  A bi-center rotary bit for drilling wells, comprising, on the one hand, a pilot tool comprising a body of revolution with an axial core and radial blades carrying cutting elements and, on the other hand, an expanding tool disposed behind the pilot tool and shifted laterally thereto, characterized in that the front face of the pilot tool (1) has an axial central zone (11) which is devoid of sharp elements (5) to allow the formation of an axial core (12), said central zone being in communication with a cavity (13) situated between two blades (4) of the pilot tool and serving for the evacuation of the core towards the periphery of the bit.
Trépan selon la revendication 1, caractérisé en ce que la cavité (13) précitée est délimitée par deux lames (4) de l'outil pilote (1) et une surface de dégagement (14) située en recul par rapport à la face avant dudit outil pilote.  Drill according to claim 1, characterized in that the cavity (13) above is delimited by two blades (4) of the pilot tool (1) and a clearance surface (14) set back from the front face of said pilot tool.
Trépan selon la revendication 1 ou 2 , caractérisé en ce que l'outil élargisseur (2) est décalé par rapport à l'outil pilote (1), de telle sorte qu'une partie (9) de sa surface périphérique soit radialement en retrait par rapport à la surface périphérique de l'outil pilote et en ce que la cavité (13) précitée de l'outil pilote (1) débouche dans ladite partie (9) de la surface périphérique de l'outil élargisseur. Drill according to claim 1 or 2, characterized in that the expanding tool (2) is offset relative to the pilot tool (1) so that a portion (9) of its peripheral surface is radially recessed. relative to the peripheral surface of the pilot tool and in that the aforementioned cavity (13) of the pilot tool (1) opens into said portion (9) of the peripheral surface of the expanding tool.
Trépan selon l'une quelconque des revendications 1 à 3, caractérisé en ce que l'outil élargisseur (2) comprend un noyau (6) avec des lames radiales (7) portant des éléments tranchants (8) et en ce que la cavité (13) précitée débouche entre deux lames (7) de l'outil élargisseur. Drill bit according to one of Claims 1 to 3, characterized in that the expanding tool (2) comprises a core (6) with radial blades (7) carrying cutting elements (8) and in that the cavity (13) above emerges between two blades (7) of the expanding tool.
Trépan selon l'une quelconque des revendications 1 à 4, caractérisé en ce que les lames (4) de l'outil pilote (1) sont spiralées.  Drill according to any one of claims 1 to 4, characterized in that the blades (4) of the pilot tool (1) are spiral.
Trépan selon la revendication 5, caractérisé en ce que les lames (7) de l'outil élargisseurs (1) sont spiralées et disposées dans le prolongement des lames de l'outil pilote.  Drill according to claim 5, characterized in that the blades (7) of the widening tool (1) are spiral and arranged in the extension of the blades of the pilot tool.
Trépan selon l'une quelconque des revendications 1 à 6, caractérisé en ce que l'outil pilote (1) comprend en outre un dispositif de rupture de la carotte (12) . Drill bit according to any one of claims 1 to 6, characterized in that the pilot tool (1) further comprises a device for breaking the core (12).
Trépan selon la revendication 7, caractérisé en ce que le dispositif de rupture comprend une pastille résistant à l'abrasion, disposée dans la zone centrale (11) précitée de l'outil pilote (1). Drill according to claim 7, characterized in that the rupture device comprises an abrasion-resistant pellet disposed in the above-mentioned central region (11) of the pilot tool (1).
Trépan selon l'une quelconque des revendications 1 à Drill according to any one of claims 1 to
8, caractérisé en ce que le diamètre de la zone centrale (11) de l'outil pilote (1) est réglée pour que la carotte (12) résiste aux efforts latéraux générés par l'outil élargisseur (2) pendant une utilisation normale du trépan. 8, characterized in that the diameter of the central zone (11) of the pilot tool (1) is adjusted so that the core (12) withstands the lateral forces generated by the expanding tool (2) during normal use of the trepan.
Trépan selon l'une quelconque des revendications 1 à Drill according to any one of claims 1 to
9, caractérisé en ce que le diamètre de la zone centrale (11) de l'outil pilote (1) est au moins égal à la différence entre le diamètre hors tout de l'outil élargisseur (2) et le diamètre de l'outil pilote (1) . 9, characterized in that the diameter of the central zone (11) of the pilot tool (1) is at least equal to the difference between the overall diameter of the expanding tool (2) and the diameter of the tool driver (1).
11. Trépan selon l'une quelconque des revendications 1 à 10, caractérisé en ce qu'il comprend en outre des canaux (10) d'alimentation en boue de forage, qui débouchent à travers la face avant de l'outil pilote (1) . 11. A drill bit according to any one of claims 1 to 10, characterized in that it further comprises channels (10) for supplying drilling mud, which open through the front face of the pilot tool (1). ).
12. Trépan selon la revendication 11, caractérisé en ce des canaux (16) d'alimentation en boue de forage débouchent entre les lames (7) de l'outil élargisseur 2.  12. Drill bit according to claim 11, characterized in that channels (16) supplying drilling mud open between the blades (7) of the expanding tool 2.
13. Trépan selon l'une quelconque des revendications 1 à 12, caractérisé en ce que les noyaux (3, 6) et les lames (4, 7) sont en acier et les éléments tranchants (5, 8) comprennent des éléments en PDC. Bit according to one of Claims 1 to 12, characterized in that the cores (3, 6) and the blades (4, 7) are made of steel and the cutting elements (5, 8) comprise PDC elements. .
14. Trépan selon l'une quelconque des revendications 1 à 13, pour le forage de puits artésiens ou dans des gisements de houille, de minerais, de pétrole ou de gaz .  14. A drill bit as claimed in any one of claims 1 to 13 for the drilling of artesian wells or in deposits of coal, ores, oil or gas.
15. Procédé pour l'approfondissement de puits préexistants, caractérisé en ce que l'on met en œuvre un trépan bi-centre conforme à l'une quelconque des revendications 1 à 14.  15. Process for the deepening of pre-existing wells, characterized in that a bi-center drill bit according to any one of Claims 1 to 14 is used.
16. Procédé selon la revendication 15, caractérisé en ce que le rayon de la zone centrale (11) de l'outil pilote (1) du trépan est au moins égal à la différence entre le rayon du puits (18) et le rayon de l'outil pilote (1).  16. The method of claim 15, characterized in that the radius of the central zone (11) of the pilot tool (1) of the bit is at least equal to the difference between the radius of the well (18) and the radius of the pilot tool (1).
PCT/EP2012/002510 2011-06-16 2012-06-14 Two-centre rotary boring bit and method for deepening an existing well WO2012171643A2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US14/125,413 US20140131111A1 (en) 2011-06-16 2012-06-14 Two-centre rotary boring bit and method for deepening an existing well
EP12732786.4A EP2721242B1 (en) 2011-06-16 2012-06-14 Two-centre rotary boring bit and method for deepening an existing well

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE2011/0371A BE1020012A3 (en) 2011-06-16 2011-06-16 BI-CENTER ROTARY TREPAN AND METHOD FOR EXTENDING PREEXISTANT WELL.
BE2011/0371 2011-06-16

Publications (2)

Publication Number Publication Date
WO2012171643A2 true WO2012171643A2 (en) 2012-12-20
WO2012171643A3 WO2012171643A3 (en) 2013-07-18

Family

ID=45478608

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2012/002510 WO2012171643A2 (en) 2011-06-16 2012-06-14 Two-centre rotary boring bit and method for deepening an existing well

Country Status (4)

Country Link
US (1) US20140131111A1 (en)
EP (1) EP2721242B1 (en)
BE (1) BE1020012A3 (en)
WO (1) WO2012171643A2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104850671B (en) * 2014-02-18 2017-03-15 中国石油化工股份有限公司 The grid cutting algorithm in rock core complexity duct

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8851205B1 (en) 2011-04-08 2014-10-07 Hard Rock Solutions, Llc Method and apparatus for reaming well bore surfaces nearer the center of drift
CA2850795C (en) * 2011-10-03 2016-08-16 Gilbert T. Meier Wellbore conditioning system
US10024105B2 (en) * 2015-02-25 2018-07-17 Radius Hdd Direct, Llc Rock bit
US10492107B2 (en) 2016-11-03 2019-11-26 Ofinno, Llc SPS configuration during handover
USD877780S1 (en) * 2017-09-08 2020-03-10 XR Lateral, LLC Directional drilling assembly
USD863919S1 (en) 2017-09-08 2019-10-22 XR Lateral, LLC Directional drilling assembly
US11111739B2 (en) 2017-09-09 2021-09-07 Extreme Technologies, Llc Well bore conditioner and stabilizer
AU2018347352B2 (en) 2017-10-10 2024-02-15 Extreme Technologies, Llc Wellbore reaming systems and devices

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5678644A (en) 1995-08-15 1997-10-21 Diamond Products International, Inc. Bi-center and bit method for enhancing stability
US20020104688A1 (en) 1999-06-30 2002-08-08 Carl Hoffmaster Bi-centered drill bit having enhanced casing drill-out capability and improved directional stability
US20020125048A1 (en) 1999-06-30 2002-09-12 Traux David K. Drill bit having diamond impregnated inserts primary cutting structure
WO2008149240A2 (en) 2007-04-23 2008-12-11 Total S.A. Bit for drilling wells and associated drilling method

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SG34341A1 (en) * 1994-12-20 1996-12-06 Smith International Self-centering polycrystalline diamond drill bit
US6039131A (en) * 1997-08-25 2000-03-21 Smith International, Inc. Directional drift and drill PDC drill bit
US6394200B1 (en) * 1999-10-28 2002-05-28 Camco International (U.K.) Limited Drillout bi-center bit

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5678644A (en) 1995-08-15 1997-10-21 Diamond Products International, Inc. Bi-center and bit method for enhancing stability
US20020104688A1 (en) 1999-06-30 2002-08-08 Carl Hoffmaster Bi-centered drill bit having enhanced casing drill-out capability and improved directional stability
US20020125048A1 (en) 1999-06-30 2002-09-12 Traux David K. Drill bit having diamond impregnated inserts primary cutting structure
WO2008149240A2 (en) 2007-04-23 2008-12-11 Total S.A. Bit for drilling wells and associated drilling method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104850671B (en) * 2014-02-18 2017-03-15 中国石油化工股份有限公司 The grid cutting algorithm in rock core complexity duct

Also Published As

Publication number Publication date
EP2721242B1 (en) 2016-01-20
WO2012171643A3 (en) 2013-07-18
EP2721242A2 (en) 2014-04-23
BE1020012A3 (en) 2013-03-05
US20140131111A1 (en) 2014-05-15

Similar Documents

Publication Publication Date Title
EP2721242B1 (en) Two-centre rotary boring bit and method for deepening an existing well
BE1015740A3 (en)
BE1016273A3 (en) Process for drilling subterranean.
BE1014353A5 (en) Cutting element and drill using the rotating element.
BE1016436A3 (en) Expandable reamer for drilling subterranean formation has blades carried by tubular body and each carrying cutting structure(s), blade biasing element, structure to retain movable blade at outermost lateral position, and actuation device
BE1015738A3 (en) ENLARGEMENT DEVICE AND METHOD USING THE SAME
US9903165B2 (en) Drill bits with axially-tapered waterways
BE1012823A5 (en) REPORTED ITEMS TO POINTE superabrasive bits EARTH DRILL.
BE1016272A3 (en) Drill and drilling method.
US8561729B2 (en) Casing bit and casing reamer designs
RU2436927C2 (en) Drilling reamer lowered on casing pipe or shank, and method of its drilling
CN103097642B (en) There is the impregnated bit of integrated reamer
US8960335B2 (en) Bit for drilling wells and associated drilling method
EA025749B1 (en) Cutting structures for fixed cutter drill bit and other downhole cutting tools
FR2752263A1 (en) TREPAN WITH SHEAR CUTTING ELEMENTS
US8245797B2 (en) Cutting structures for casing component drillout and earth-boring drill bits including same
CN105658900A (en) Fixed cutter drill bit with multiple cutting elements at first radial position to cut core
CN107476766A (en) Cutting element recess with release characteristic
BE1014014A5 (en) Rotary drag bit, for drilling subterranean formations, has blades, post-like cutting structures, and polycrystalline diamond compact cutters
BE1014333A3 (en) Rotating rock drill bit for drilling wellshafts comprises fluted body carrying cutting elements on front face, with cross-sectional area or grooves in body reduced near rear face of body
FR2646875A1 (en) Rotary-percussive boring bit with ultra-hard biting elements
JP2017008502A (en) Drill bit for core sampling, hole adjustment member and drilling method
BE669193A (en)
WO2022148867A1 (en) Deep drilling method and drilling assembly
CN111425139A (en) Composite drill bit

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12732786

Country of ref document: EP

Kind code of ref document: A2

WWE Wipo information: entry into national phase

Ref document number: 2012732786

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 14125413

Country of ref document: US