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
  • E21B10/00—Drill bits
  • E21B10/08—Roller bits
  • E21B10/18—Roller bits characterised by conduits or nozzles for drilling fluids
• • 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
  • E21B10/00—Drill bits
  • E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
  • E21B10/50—Drill bits characterised by wear resisting parts, e.g. diamond inserts the bit being of roller type
• • 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
  • E21B7/065—Deflecting the direction of boreholes using oriented fluid jets

Definitions

• the present invention relates generally to bits for drilling a borehole, and more particularly to a drill bit for horizontal directional drilling (HDD) with improved directional control.
• HDD horizontal directional drilling
• HDD horizontal directional drilling
• rock drill bits both rolling cone and fixed cutter
• these "trenchless holes” are drilled under rivers, roads, or other developed areas.
• the bit is directionally controlled or steered underneath or around these obstacles.
• the bit encounters and is steered around obstacles including power lines, water mains, and other obstacles in drilling the horizontal hole.
• the ability to accurately and reliably steer the bit facilitates successful project completion.
• Boreholes formed with directionally controlled drill bits are used to route underground sewer lines, water lines, and fiber optic cables, and the like.
• each cone 5 that includes three cones 10a, 10b, and 10c, each supporting multiple cutters 1 1.
• the cutters 11 are arranged in intermeshed rows.
• Each cone is associated with a drilling fluid nozzle 7a, 7b, and 7c.
• One embodiment of forming the three cone bit 5 is to weld the components as shown and described in U.S. Patent No. 4,414,734 to Atkinson, which is hereby incorporated by reference.
• cone 10a including the pin to which it is rotatably mounted may be removed.
• a push plate (not shown) is installed in the space created by the removal of the cone and the pin. The push plate provides a lever to push the bit in the desired direction and maintain balanced drilling with the two remaining intermeshed cones 10b, 10c.
• the borehole bottom refers to the undrilled portion of the borehole which the bit will encounter upon continued drilling
• the sidewall of the borehole refers to the sidewalls that are generally perpendicular to the borehole bottom.
• the result may be an outer uncut ring 12 and an inner uncut ring 13 corresponding to the respective rows of cutters of the removed cone 10a.
• This uncut borehole bottom is known in the drilling industry to reduce rate of penetration and cause lateral bit instability (also referred to as off center running), which can result in reduced steerability of the bit.
• a center jet nozzle 14 is disposed substantially on the axis of rotation 15 of the bit 5.
• the center jet nozzle 14 directs drilling fluid generally along the bit rotation axis 15 such that the drilling fluid impinges on the borehole bottom where it may remove sticky formation.
• the center jet nozzle 14 is modified such that the drilling fluid flow impinges on the rolling cones 10b, 10c where it may remove sticky formation or rock cuttings from the cones themselves.
• one or more of the nozzles 7a, 7b, and 7c is plugged to cause the drilling fluid to flow to an open nozzle where it can be controlled to fluidly erode the formation in a desired direction of advancement of the bit.
• Directional control and rate of penetration of drill bits used for horizontal directional drilling may still be improved.
• a bit body for a drill bit for horizontal directional drilling includes a pair of legs and a small wedge member disposed between the pair of legs.
• a roller cone is rotatably mounted to each bearing shaft extending from a respective leg. The roller cones support full coverage cutting structures.
• a center jet nozzle is configured to direct drilling fluid between the pair of roller cones.
• the bit body includes a large wedge where the included angle of the large wedge member is greater than the included angle of the small wedge member.
• the large wedge member may be welded to the legs on one side of the bit body, and the small wedge member may be welded to the legs on the other side of the bit body.
• a stabilizer member extends from the bit body and is configured to maintain a drilling orientation of the drill bit within a borehole.
• the stabilizer may include wear protection elements applied to its outer surface.
• An alternate embodiment of a bi-cone drill bit for horizontal directional drilling according to the teachings of the present disclosure includes an extended nozzle that extends between the two legs and directs a stream of drilling fluid to be concentrated near a borehole bottom to fluidly erode a formation to aid in steering the bi-cone bit.
• One technical advantage to embodiments taught by the present disclosure is a bi-cone bit employing full coverage roller cones to ensure that the borehole bottom is fully addressed by the cutting elements supported by the roller cones such that rings of uncut formation are not left due to the removal of one of three intermeshed roller cones.
• a further technical advantage includes a bi-cone drill bit for use in horizontal directional drilling that employs conventionally fabricated legs of a three cone bit including full sized bearings.
• Still a further technical advantage includes a bi-cone bit that is configured to fluidly erode an earth formation at a transitional zone of a borehole located between a borehole sidewall and a borehole bottom while maintaining a generally upright drilling position of the drill bit.
• Figure 1 illustrates a face of a conventional three cone roller cone drill bit
• Figure 2A illustrates a body of a bi-cone bit for use in horizontal directional drilling according to an embodiment of the present disclosure
• Figures 2B and 2C are perspective views of wedge members forming the bit body of Figure 2A;
• Figure 3 illustrates a face of the bi-cone bit of Figure 2A
• Figure 4 is a cross-section of the bi-cone bit of Figure 2A illustrated in a drilling position within a borehole;
• Figure 5 is a cross section of an embodiment of the large wedge member and a stabilizer member of Figure 4 with hardfacing material applied to enhance wear resistance;
• Figure 6 is a cross section of an alternate embodiment of the large wedge member and the stabilizer with wear resistant inserts enhancing wear resistance
• Figures 7A and 7B are respectively a face view and a cross-section of an alternate embodiment of a bi-cone bit including an extended nozzle for use in horizontal directional drilling according to the teachings of the present disclosure.
• Figure 2A illustrates a body of a bi-cone bit 16 for use in horizontal directional drilling ("HDD").
• the "shirttail” portion of each of two legs 18a, 18b is omitted to show details of the body of the bit 16.
• the omitted shirttail portions include the bearing shafts and the two roller cones that are each rotatably mounted to a respective bearing shaft.
• the body of the bi-cone bit 16 includes a small wedge 20 that is disposed between the legs 18a and 18b on one side, and a large wedge 22 that is disposed between the legs 18a and 18b on the other side.
• One advantage of the bi-cone bit 16 is that the body includes conventional legs 18a, 18b.
• the legs 18a, 18b are conventionally formed as machined steel forgings, and according to certain embodiment are stock parts used in the manufacturing of conventional three cone bits.
• each leg 18a, 18b includes a nozzle 24a, 24b, each of which is blocked by a plug 26a, 26b in order to direct full drilling fluid flow through a center jet nozzle 28 to steer the bit 16, as described in more detail below with respect to Figure 4.
• the bit body is formed by welding together the leg 18a, the small wedge 20, the leg 18b, and the large wedge 22. Specifically, a leg face 30a proximate the nozzle 24a is abutted to a large wedge face 32. A leg face 34a opposite of leg face 30a is abutted to a small wedge face 36. Similarly, for the other leg 18b, a leg face 34b is abutted to a large wedge face 38, and an opposite leg face 30b is abutted to a small wedge face 40.
• the components are welded or otherwise joined together to form the body of bi-cone bit 16. In this manner, the small wedge 20 and the large wedge 22 together occupy the space that would otherwise be occupied by the third leg of a conventional three cone bit.
• the small wedge 20 has an included angle ⁇ 1 sufficient to prevent the cutters of the two cones from striking and interfering with the rotation of the cones, as described in more detail below with respect to Figure 3. In one embodiment, this included angle is approximately 20°-30°.
• the large wedge 22 has an included angle ⁇ 2 of approximately 120° minus the included angle ⁇ 1 of small wedge 20 and is greater than the included angle ⁇ 1 of small wedge 20. In the illustrated embodiment, ⁇ 1 is approximately 20° and ⁇ 2 is approximately 100°.
• the small wedge 20 includes a cavity portion 42, and the large wedge includes a cavity portion 44.
• the small wedge 20 and the large wedge 22 are formed by machining steel forgings similar to the fabrication of the legs 18a, 18b. For example, the steel forgings of the small and the large wedges are machined to form threads 46 that enable the bi-cone bit 16 to be coupled to a drill string.
• the cavity portions 42 and 44 with the legs 18a and 18b the bit body defines a central plenum through which drilling flows from the surface to the center jet nozzle 28.
• FIG. 3 shows a face of the bi-cone bit 16.
• the face includes a cone 46a rotatably mounted to the bearing shaft extending from leg 18a and a cone 46b rotatably mounted to the bearing shaft extending from leg 18b.
• a bottom surface of the large wedge 22 provides a robust location for attaching, adhering, or otherwise implementing a stabilizer 48.
• Each cone 46a, 46b of the bi-cone bit 16 supports a plurality of cutters 50.
• the cutters may be PDC cutter inserts that are cone-shaped, dome-shaped, chisel-shaped or any other suitable cutting structure that is known in the art.
• the cones 46a, 46b are full coverage cutter cones because the cutters 50 are positioned at locations over the entire surface of each cone such that the full borehole bottom is addressed by one or more cutters 50 on each of cones 46a, 46b. In certain embodiments, the cutters 50 are randomly positioned on the cones.
• the full coverage cones 46a, 46b together apply cutters 50 to the full bottom of the borehole, as opposed to the intermeshed rows of the remaining cones of a modified three cone bit as shown and described with respect to Figure 1.
• the included angle ⁇ 1 of the small wedge 20 is selected such that the full cutter coverage cones 46a does not interfere with the full coverage cutter cone 46b.
• full cutter coverage cones 46a, 46b are employed instead of cutters formed in intermeshing rows as shown and described above with respect to the three cone bit shown in Figure 1.
• each leg 18a, 18b supports a full size bearing for each of cones 46a, 46b.
• the large wedge 22 and the small wedge 20 are formed as a single integral steel machined forging.
• the stabilizer 48 extends from the large wedge 22.
• the stabilizer 48 is generally a wedge-shaped machined steel forging. In some embodiments, the stabilizer is formed integrally with the large wedge 22. In other embodiments, the stabilizer 48 may be welded, brazed, or otherwise attached to a bottom surface of the large wedge 22.
• a function of the stabilizer 48 is to maintain upright drilling position orientation of the bi-cone drill bit 16 during drilling and during a halt in drilling when the drilling fluid nozzle is employed to fluidly erode the formation to facilitate directional control of the bit 16.
• the stabilizer 48 includes generally rounded surfaces to minimize any cutting of the borehole sidewall 52 by the stabilizer 48. Also, the stabilizer 48 is disposed above the bottom 54 of the borehole to ensure that the bottom 54 of the borehole is not addressed and possibly cut by the stabilizer 48.
• the cutting and drilling action of the bi-cone bit 16 is performed by the cutters 50 supported by the cones 46a, 46b (only one cone shown in Figure 4). During drilling, the stabilizer 48 ensures balanced drilling such that the orientation of the bit in the borehole is maintained by the outer surface of each leg 18a, 18b, the outer surface of the large wedge 22, and the stabilizer 48.
• the stabilizer 48 also maintains the balance of the bi-cone bit 16 when operating the center jet nozzle 28 to facilitate bit steering.
• the center jet nozzle 28 receives drilling fluid from the plenum and is configured to direct the drilling fluid between cone 46a and cone 46b.
• the center jet nozzle 28 is oriented at an angle with respect to the axis of rotation or centerline of the bit. This angle is selected such that the fluid flow impacts the transitional zone 53 between the borehole sidewall 52 and the bottom 54 of the borehole such that formation is eroded and a depression or grove is created, which will aid in steering the bit.
• the bi-cone bit 16 may be advanced into the earth and rotated about its rotational axis to create the borehole through the cutting action of the cutters 50 supported by the cones 46a, 46b. If an obstacle is encountered that the bit is to be steered around, the bit rotation can be halted such that the center jet nozzle 28 is positioned to direct a stream 56 of drilling fluid from the center jet nozzle 28 to erode an area of the borehole in the desired direction to steer the bit 16. A grove is eroded or cavity is eroded in the formation by the drilling fluid stream 56. The bit 16 is then positioned in the grove and bit rotation is restarted such that the bit drills formation in the steered direction.
• the center jet nozzle stream 56 is oriented with respect to the circumference of the bit 16 such that the location of impingement of the nozzle stream 56 with the formation is approximately 180° opposed to the stabilizer 48. In this manner, the contact between the sidewall 52 and the stabilizer 48 opposes the force created by the center jet nozzle 28 and maintains the bit in an upright orientation.
• the location of impingement may be 135°-225° opposed to the stabilizer 48.
• the nozzle stream 56 by be angled in a generally forward direction toward cone 46b or a generally rearward direction toward cone 46a may be applied to aid the steering of the bi-cone bit 16.
• FIG. 5 illustrates a cross section of an alternate embodiment of the large wedge 22 and the stabilizer 48.
• erosion resistance of the stabilizer 48 is enhanced by applying wear resistant material to an outer surface of the large wedge 22 and/or the stabilizer 48 at locations that are particularly susceptible to erosion due to contact with the sidewall 52 of the borehole.
• a layer of welded hardfacing material 58 is applied to the outer surface of the large wedge 22 and/or the stabilizer 48.
• the hardfacing material 58 is a deposit of tungsten carbide hard metal.
• the material is typically pelletized tungsten carbide carried in a welding medium primarily composed of nickel. High heat is used to apply a layer of the hardfacing material 58.
• the hardfacing material 58 may be substantially flush with the outer surface of the large wedge 22.
• Erosion resistant inserts 60 are press-fit or brazed in a cavity formed in the stabilizer 48.
• the erosion resistant inserts 60 are generally cylindrical tungsten carbide members that are press-fit or brazed into cavities formed in an outer surface of the large wedge 22.
• the erosion resistant inserts 60 may also be press-fit or brazed into a cavity formed in an outer surface of the stabilizer 48.
• the wear resistant inserts 60 may provide wear resistance that is superior to the wear resistance of the hardfacing material 58 because of the tendency of the welding medium, typically nickel to break down when drilling highly abrasive rock formations.
• the wear resistant inserts 60 may be polycrystalline diamond compact
• PDC physical compact disc
• inserts in the form of impregnated diamond slugs inserts in the form of impregnated diamond plates.
• These erosions resistance inserts 60 may be either press-fit or brazed to secure them to the large wedge 22 and/or stabilizer 48 at locations that are susceptible to erosion.
• the holes that receive the inserts must be located at some appreciable distance from an edge in order for the press- fit to function properly and peripherally retain the inserts 60.
• tungsten carbide plates may be brazed to an outer surface of the large wedge 22 and/or the stabilizer 48 similar to the teaching of tungsten carbide plates applied to a leading transitional leg surface of a three cone bit, as disclosed and described in U.S. Patent App. Pub. No. 2014/0299384 by Harrington et al., which is hereby incorporated by reference.
• FIGS 7A and 7B illustrate respectively a face and a cross section of an extended nozzle HDD bi-cone bit 61 according to an alternate embodiment of the present disclosure.
• An extended nozzle 62 extends downward such that it is proximate the borehole bottom 28.
• the extended nozzle 62 is disposed between cone 46a and cone 46b.
• the extended nozzle 62 extends from the small wedge 20.
• a conduit 64 runs through the small wedge 64 and the extended nozzle 62.
• the conduit 64 fluidly couples an outlet 66 of the extended nozzle 62 to the plenum.
• the extended nozzle 62 allows drilling fluid to be focused at a particular location of the borehole.
• the outlet 66 of the extended nozzle 62 may be less than about seven times the diameter of the nozzle orifice away from the borehole bottom 28.
• an exit plane of the outlet 66 of the extended nozzle 62 is disposed within about 3.5 inches (7 x 0.5) above the borehole bottom 54 and oriented toward the transitional zone 53 between the borehole sidewall 52 and the bottom 54 of the borehole.
• the exit plane is the plane at which the drilling fluid exits the nozzle and begins to form drilling fluid 68 generally in the form of a cone.
• the cone of drilling fluid 68 from the extended nozzle 62 erodes formation and generates a depression or grove, which will aid in steering the bit, as described above with respect to Figure 4.
• the extended nozzle 62 is circumferentially oriented on the extended nozzle bi- cone bit 61 such that the location of impingement of the drilling fluid is approximately 180° degrees opposed to the stabilizer 48. According to an alternate embodiment, the location of impingement may be 135°-225° opposed to the stabilizer 48.
• the nozzle stream 68 by be angled in a generally forward direction toward cone 46b or a generally rearward direction toward cone 46a may be applied to aid the steering of the bi-cone bit 61.
• the exit plane of the outlet 66 of the extended nozzle 62 is not parallel with the borehole bottom 54, but rather is angled to focus the drilling fluid even more directly toward the transitional zone 53 between the borehole wall 52 and the borehole bottom 54.
• the embodiments disclosed herein resolve problems of lateral instability related to excessive uncut borehole bottom, and thereby increase the rate of penetration and increase lateral stability and also reduce off center running.
• the directional control of a bi-cone bit used for horizontal directional drilling is substantially improved.
• the disclosed embodiments provide improved steerability by providing efficient hydraulic energy focused on a selected portion of the borehole to erode formation and aid in directional control of the HDD bit.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (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)
• Mechanical Engineering (AREA)
• Earth Drilling (AREA)

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• 2015
  • 2015-02-06 EP EP15745800.1A patent/EP3102772A4/de not_active Withdrawn
  • 2015-02-06 WO PCT/US2015/014880 patent/WO2015120311A1/en active Application Filing
  • 2015-02-06 AU AU2015213772A patent/AU2015213772A1/en not_active Abandoned
  • 2015-02-06 US US14/616,361 patent/US20150226007A1/en not_active Abandoned

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