Extended reach drilling

Abstract

Apparatus, methods and uses that allow extended reach drilling by virtue of the provision in the drillstring and to downhole tools collective vibrations, not tuned specifically to a single resonant frequency, from a hammer assembly that provides vibrations of different frequency ranges.

1 . A method of extended reach drilling which comprises
 providing a 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 mass or cross sectional 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 (beat frequency) generated at the strike interface, the 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 specifically tuning the drill string for resonance, although some optimisation responsive to different strata might occur.   
     
     
         2 . A method as claimed in  claim 1  wherein said top hammer to be powered by hydraulic, pneumatic, electric, mechanical or electromagnetic means. 
     
     
         3 . A method of extended reach drilling which comprises
 providing a 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.   
     
     
         4 . A method of  claims 1  to  3  wherein there are subsequent uphole frequencies reflected from those generated at the strike or impact interface of the top hammer assembly. 
     
     
         5 . A method of enhancing the reach of a drill string downhole using a top hole hammer functionality, the method comprising, without 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 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 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.   
     
     
         6 . A drilling apparatus having a top hole hammering functionality able, 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. 
     
     
         7 . A top hammer apparatus for 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 100 Hz, 100 Hz to 1000 Hz and 1000 Hz to 10000 Hz. 
     
     
         8 . Apparatus of  claim 7  wherein the i length of the stress waves are very short. for example the wave length=the speed of sound in steel (5,000 metres per second) divided by the frequency, so the wave length at 10,000 Hz=0.5 Meters, at 1,000 Hz=5 meters, at 100 Hz=50 Meters 
     
     
         9 . 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). 
     
     
         10 . Apparatus as claimed in any of  claims 5  to  8  wherein said apparatus includes a top hammer that is configured with impedances, excitation features, masses or the like to provide said frequencies. 
     
     
         11 . Apparatus of  claim 9  wherein the range or frequency can be defined as going from a first to a Nth range. 
     
     
         12 . 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. 
     
     
         13 . The use of  claim 12  wherein any number (N) of frequencies or frequency ranges are used. 
     
     
         14 . The use of  claim 12  or  13  wherein some or several frequencies are non-incident. 
     
     
         15 . 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. 
     
     
         16 . Apparatus of  claim 15  wherein frequencies within the following ranges 0-100 Hz, 100-1000 Hz, 1000-10,000 Hz, etc are generated by both incident frequencies of a strike and nonincident and/or impeded frequencies resulting from the strike. 
     
     
         17 . 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. 
     
     
         18 . An impact/vibrational assembly capable of impacting a drill bit on a bore face, the assembly comprising or including
 a drill string,   a drill bit, and   a drill head, that is capable of attaching to the drill string,   wherein 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.   
     
     
         19 . An assembly of  claim 18  wherein 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.