Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B7/00—Special methods or apparatus for drilling
  • E21B7/24—Drilling using vibrating or oscillating means, e.g. out-of-balance masses
• • 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
  • E21B6/00—Drives for drilling with combined rotary and percussive action
  • E21B6/02—Drives for drilling with combined rotary and percussive action the rotation being continuous
  • E21B6/04—Separate drives for percussion and rotation
• • 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
  • E21B1/00—Percussion drilling
  • E21B1/02—Surface drives for drop hammers or percussion drilling, e.g. with a cable
  • E21B1/04—Devices for reversing the movement of the rod or cable at the surface
• • 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
  • E21B10/36—Percussion drill bits
• • 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
  • E21B28/00—Vibration generating arrangements for boreholes or wells, e.g. for stimulating production

Definitions

• the present invention relates to extended reach drilling.
• the invention more particularly, but not solely, relates to methods of extended reach drilling, with a drilling apparatus able to effect extended reach drilling and operation of a downhole drill string in extended reach drilling with the generation and transfer of enabling or synergistic spread of vibration.
• Methods of enhancing the reach of a drill string and downhole tooling using a top hammer comprising, without specifically tuning for resonance, generating a spectrum where the output energy of the hammering impacts at least to some extent is localised to first order of magnitude spread of frequencies, yet the configuration uphole of the drill string supporting assembly (the impacting or vibrational device) is such that, by impedance, excitation, mass affects, or the like, a greater spectral spread of the vibrational energy, and of frequencies over several orders of magnitude, passes downhole and/or in combination with some subsequent frequencies being reflected back uphole thereby to enable the extended reach drill string operations, and operating the drill string with such a modified spectrum of vibrational frequencies passing into it.
• Top hammer drilling has been used for many years within the mining industry to rapidly advance drill bits into ground formations.
• top hammers have traditionally been energised by either pneumatic or hydraulic power. Such hammers are designed to generate large impact shock waves with minimal mechanical impedance between the impacting piston and the drive shaft (the connection between the piston and the drill rods) via drill rods to a drill bit and providing large amplitude of movement, giving very rapid penetration through relatively short distances, as has been the requirement for blast holes - typically up to 30 meters.
• the present invention envisages using impact pulses and wide spread bands of vibrations to advantage when drilling.
• the invention also relates to the use downhole of a first frequency, or a first frequency range (e.g. able to break rock with or without resonance) and a distinct second frequency, or second frequency range (e.g. to avoid formational grab on the drill string), to excite, for different functionalities, the drill string and/or the tool or bit.
• N any number (N) of frequencies or frequency ranges can also be used to advantage.
• the invention is a method of extended reach drilling which comprises
• top hammer assembly from which a drill string is dependant, the top hammer assembly, or the top hammer assembly and the proximate region of the drill string, being configured by impedances, excitation features, or the like to provide excitations to provide multiple localised bands of frequencies that differ from the band or bands of frequencies to be generated at the strike interface, such band(s) at the strike interface themselves(s) not of a power (due to the mechanical impedances designed into the system) or variation of frequencies sufficient to allow extended reach drilling, and operating the top hammer assembly during operation of the drill string in an extended reach drilling operation, without reference to drill string length variation, although some optimisation responsive to the manipulation of the impacting frequencies in different strata might occur.
• the invention is a method of extended reach drilling which comprises
• top hammer assembly from which a drill string is dependant, the top hammer assembly, or the top hammer assembly and the proximate region of the drill string, being configured by impedances, excitation features, masses, or the like to increase the spread of vibrational frequencies to pass into and downhole along the drill string from those generated at the impact interface of the top hammer assembly,
• the method comprising operating the top hammer assembly during drill string dependant downhole operations at a power, or in a finite power range, into the top hammer assembly, without reference to drill string length for resonance purposes.
• the invention is a method of enhancing the reach of a drill string downhole using a top hole hammer functionality, the method comprising, without tuning for resonance,
• the invention is a drilling apparatus having a top hammer functionality able, top hole, to support and/or provide vibration to a drill string that extends downhole and to allow deep reach drilling activities characterised in that a spectrum of different orders of magnitude of vibrational frequency are or can be passed into the drill string without reference to its length, from an impact generated spectrum of lesser order of magnitude of vibrational frequency spread not, of itself, able to allow the deep reach drilling activities.
• the invention is a top hammer assembly usage in extended reach drilling operations characterised in that an impact produced range of vibrations in the range of from 0 to 100 Hz not sufficiently of an energy to allow extended reach drilling operations is modified by passive configurational features of the assembly to allow and/or produce bands of vibrations in each of the ranges 0 to 100Hz, 100Hz to 1000Hz and 1000Hz to 10000Hz. It is this frequency rich vibrational content that cause the down hole tools (drill rods, drill bits, reamers etc) to become excited and vibrate at multiple frequencies- but with (compared to conventional top hammers) small displacement amplitudes that minimise frictional damping in the drill string and therefore allows for efficient energy transfer to the drill bit which collectively and synergistically allow extended reach drilling operations.
• the impulse length of the stress waves are very short and
• the invention is apparatus including a drill string and drill string dependent tool where there is provision from within and/or without the drill string to generate for and/or to the drill string, for and/or to the tool, or both, a frequency or a range of frequencies to provide multiple vibration(s).
• the range or frequency could be defined as going from a first to a Nth range.
• the invention is the use of a first frequency or frequency range and at least a second frequency or second frequency range in a drill string having a drill bit.
• N any number (N) of frequencies or frequency ranges can be used.
• frequencies can be generated (e.g. by an oscillator) to be incident downhole some or several frequencies can be non-incident (e.g. reflected).
• Such reflected and/or incident frequencies may be caused to vary by the nature of the overall apparatus.
• the invention is an oscillating (vibrational)apparatus that outputs at least two vibrational frequencies and/or frequency ranges with first frequency or frequencies in the kilohertz range e.g. (>1000 Hz) and the second frequency or frequencies in the tens hertz range e.g. ( ⁇ 100 Hz) for drilling through sub terrain.
• Envisaged are frequencies within the following ranges 0-100 Hz, 100 -1000 Hz, 1000 -10,000 Hz, etc.
• the invention is a multi-oscillating (vibrational) apparatus capable of being tailored to drill through sub terrain reliant on specified or discrete frequency or frequency ranges for specific purposes in the drilling function.
• the invention is an impact/vibrational assembly capable of impacting a drill bit on a bore face, the assembly comprising or including
• a drill head that is capable of attaching to the drill string
• each of the drill string, drill bit and drill head each have a mass, or masses, that can be excited to vibrate at functional frequencies.
• the drill head provides with a striking directly some functional frequencies and said masses responsive to the striking provides other functional frequencies to which at least one of the drill string and drill bit responds with an excitation.
• the excitation is by means of one or more oscillator(s) whether in the drill string, in the drill head, in the drill bit, or some hybrid of those choices.
• the device may optionally or preferably have dampers that negate non useful frequencies.
• the primary vibrational frequencies are totally or in part generated by, hydraulic, pneumatic, eccentric drive, electromagnetic, electric, or mechanical top hammer functionality.
• extended reach contemplates drilling to greater, and indeed very much greater than, say, 50 metres.
• the capabilities are to allow downhole operations (drilling, reaming, etc) that extend for deeper than the depths of 30 metres, 50 metres and 100 metres acknowledged as depth limits for existing techniques.
• This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known
• Figure 1 shows a conventional hydraulic/pneumatic top hammer arrangement, the impact device being on the right and involving a hammering shuttle (commensurate to its impact face in cross-section) responsive to input pressure(s) and exhaust actuation (shown diagrammatically) and subject to drill string rotation apparatus to drive a downhole drill bit or other downhole tool, these top hammers generating significant impact force of (relatively) long duration which provides significant force and large amplitudes of movement of the drill bit into the formation - but with most of the impact energy in frequencies at or near the beat frequency (the number of hammer impacts per second) but without generating significant additional frequency rich vibrational content of very short duration
• Figure 2 shows a typical impact graph resulting at the interface from the hammering effect of an arrangement as in Figure 1,
• Figure 3 shows a sonic drill arrangement, this time reliant on eccentrics to generate substantially sinusoidal inputs, but again showing a drill string rotational apparatus and a downhole drill bit,
• Figure 4 shows a typical sinusoidal output of such an eccentric driven vibrational arrangement for sonic drilling
• Figure 5 is the conceptual arrangement of the present invention showing an impact device to the right acting down a drill string to a drill bit or other downhole tool (optionally via a spring), the impact device being hereinafter described in more detail by reference to an example,
• Figure 6 shows an extended reach hydraulic or pneumatic top hammer arrangement as an example in accordance with the present invention to be the impact device at the right of, for example, the layout as in Figure 5 or to operate without the spring arrangement shown,
• Figure 7 shows a still further embodiment reliant on a hydraulic or pneumatic top hammer arrangement
• FIGS 5,6,&7 showing embodiments of an extended reach Top hammer device, whereby the various masses, dimensional changes and stiffnesses of the assembly encourage a broad band pulse of vibrational energy to be transmitted to the dill string when excited by a short duration impact ( ⁇ 0.0005 s ) of relatively low energy
• Figure 8 shows a typical spectral plotplot (Amplitude/Frequency) of the response downhole resulting from an impact when using an extended top reach hammer such as shown in Figure 5, 6, or 7
• Resonance devices - (such as eccentric drive “sonic” devices) strive to resonate the entire drill string - thus causing an axial (hammering) movement back and forth of the drill bit.
• an impact device 1 with a reciprocatable piston, anvil or shuttle 2 as the hammer to strike at least one impact face 3 forming part of or connecting
• a rotational drive apparatus 6 to rotate the drill string of rods 4 is provided.
• This arrangement drills hard rock very rapidly - although the distance (or depth) capability is typically less than 50 meters.
• the eccentric vibrational apparatus 8 of Figure 3 generates likewise into a drill string of rods 7 to a drill bit 9, the drill string being rotatable by a drive 10.
• the sonic drill system of Figure 3 generates a smooth sinusoidal force wave (as in Figure 4) from the input of the rapidly rotating eccentric masses.
• the depth to which sonic drill rigs can operate is ultimately dictated by the speed to which the eccentrics can be rotated. It is also important to note that there is a one to one relationship between the input frequency and the drill rod/bit frequency (e.g. if 100Hz is required to maintain resonance in the drill string - then an input frequency of 100Hz is required). Our device is quite different to these systems in that what we propose allows the drill bit to become excited and therefore oscillate INDEPENDENTLY and at higher frequencies than the drill string.
• Keskiniva WO 2010/037905 Al has a feed back device for controlling reflected stress waves.
• Keskiniva US 7891437B2 looks to optimise impact force and the length of the stress wave.
• Watanabe US 6454021 Bl uses a magnetostrictive material with an electrical pulse and coil to alter the pulse characteristics of the drilling machine.
• Figure 5 shows a system with an impact device 11 such as will be described with respect to the present invention driving directly or indirectly down a drill string of rods 12 to a drill bit or other downhole tool 13.
• a spring 14 can be provided in the drill string.
• FIG. 6 shows a preferred embodiment.
• An impact device 15 interacts with a drill string 16 to a drill bit 17 or other downhole tool.
• the drill string 16 is one with drill rods 18 and a drive to rotate the drill string. This drive 19 can be positioned
• Masses 20 and 21 are movable relative to the surrounding structure 22 (e.g. by moving one or the other of the shuttling anvil or its surround, or both). As can be seen, at least for the mass 20, there is shown a pair of opposed impact faces A and B to act alternately and respectively with impact faces A and B of the surround structure 22.
• Figure 7 shows another alternative way (again with input pressures and exhaust pressures) able to cause, as a piston, the member 23, as an anvil, to move backwards and forwards in alignment with the drill string direction so as to impact on impact face 24 and impact face 25.
• an isolation spring 26 can be provided and there can be input to turn the drill bit from zone 27.
• the initial impact frequency is broken into multiple frequencies of varying magnitude as the impact wave travels longitudinally through the hammer and causes the primary and secondary masses (there may be more than two) connected by various stiffnesses to vibrate over a wide band of distinct frequencies. These distinct stress wave vibrations move down the drill string to the drill bit. It is speculated that the larger amplitude vibrations carry out the majority of the rock breaking - while the higher frequency vibrations also assist in localised rock fracture - but more importantly cause fluidization of the formation being drilled and minimise "frictional grab" (damping)on the drill rods.
• a hammer that provides an initial impact or hitting force of 40 tonnes will provide an output force at the drill bit of between 12-15 tonnes.
• Such a hammer will be operated at 50Hz.
• the reduction in peak force, being between 25-27 tonnes, is into the creation of the multiple frequencies as shown in the spectral plot of Figure 8 or some other version with multiple localised bands of frequencies, each with its own amplitude spread.
• Figure 6 and 7 suggest how a hydraulic or pneumatic top hammer can achieve outcomes wanted.
• the piston or hammer is propelled into the drive shaft by (probably) hydraulic or pneumatic energy, or mechanical energy (e.g. rotating eccentric masses).
• hydraulic or pneumatic energy or mechanical energy (e.g. rotating eccentric masses).
• the top hammer assembly usage in the extended reach drilling operations is characterised in that an impact produced range of vibrations in the range of from 0 to 100Hz, not sufficiently of an energy to allow extended reach drilling operations, is modified, by passive configurational features of the assembly, to allow and/or produce bands of vibrations in each of the ranges 0 to 100Hz, 100Hz to 1000Hz and 1000Hz to 10000 Hz which collectively and synergistically allow extended reach drilling operations.
• an advantage in generating a profile of multiple spectrum vibrational frequencies that, when combined, together, provide numerous advantages over conventional technologies including the following:
• the apparatus is able to deliver two (or more) identifiable frequency bands via the drill string to the formation that is being drilled.
• Such frequencies can be generated by a top hammer apparatus that is made up of different components - wherein each component has differing masses each connected by varying stiffness elements and varying ratio dampers that results in the apparatus having several differing natural frequencies.
• Each natural frequency can be determined by the usual formulae for such systems with appropriate changes made to the masses and stiffness of the material of each component to alter the natural frequencies generated.
• the present invention is to generate multi frequencies that allows drilling in various formations to long distances - potentially hundreds of meters.
• the specific vibrations work to minimise friction on the drill string, and are sufficient to allow competent rock formations to be penetrated.
• the frequencies could provide at least one frequency in the kilohertz range (above one thousand Hz) and another frequency operating in the tens of Hz range (e.g. 60 Hz).
• Such frequencies are dependent on the masses of each individual part making up the drilling assembly, where each part has its own inherent natural frequencies such that the combination of frequencies generated can enhance, cancel out, or maintain the multitude of frequencies generated.

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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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• 2012
  • 2012-12-18 US US14/366,377 patent/US20140332278A1/en not_active Abandoned
  • 2012-12-18 WO PCT/NZ2012/000240 patent/WO2013095164A1/en active Application Filing
  • 2012-12-18 EP EP12858853.0A patent/EP2795032A4/de not_active Withdrawn

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