Plasma channel drilling process
First Claim
1. A method of removing material from a body of material comprising providing a high voltage pulsed generator coupled to an electrode assembly, and repeatedly per second generating electrical pulses with a duration in the range 1-50 microseconds and a voltage rise time of less than 150 nanoseconds to create a plasma channel within or on the surface of the body of material, thereby causing material to fracture and fragment from the body due to the rapid expansion of each plasma channel following electrical breakdown of the material.
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Accused Products
Abstract
Material is removed from a body of material, e.g. to create a bore hole, by plasma channel drilling. High voltage, high energy, rapid rise time electrical pulses are delivered many times per second to an electrode assembly in contact with the material body to generate therein elongate plasma channels which expand rapidly following electrical breakdown of the material causing the material to fracture and fragment.
93 Citations
40 Claims
- 1. A method of removing material from a body of material comprising providing a high voltage pulsed generator coupled to an electrode assembly, and repeatedly per second generating electrical pulses with a duration in the range 1-50 microseconds and a voltage rise time of less than 150 nanoseconds to create a plasma channel within or on the surface of the body of material, thereby causing material to fracture and fragment from the body due to the rapid expansion of each plasma channel following electrical breakdown of the material.
- 12. An apparatus comprising a high voltage pulsed generator coupled to an electrode assembly located at a material-removal station, said apparatus being adapted to generate repeatedly per second electrical pulses with a duration in the range 1-50 microseconds and a voltage rise time of less than 150 nanoseconds to create a plasma channel repetitively per second within or on a surface of the body of material, thereby to remove material by the rapid expansion of each plasma channel fracturing and fragmenting the body of material.
- 24. A method of removing material from a body of material comprising providing a high voltage pulsed generator coupled to an electrode assembly, and repeatedly per second generating electrical pulses having a voltage in the range 10-50 kV to create a plasma channel within or on the surface of the body of material, thereby causing material to fracture and fragment from the body due to the rapid expansion of each plasma channel following electrical breakdown of the material.
- 35. An apparatus for removal of material from a body of material, the apparatus comprising a high voltage pulsed generator coupled to an electrode assembly located at a material-removal station, said apparatus being adapted to generate electrical pulses in the range 10-50 kV to create a plasma channel repetitively per second within or on a surface of the body of material and material is removed by the rapid expansion of each plasma channel fracturing and fragmenting the body of material.
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38. A method of removing material from a body of material comprising providing a high voltage pulsed generator coupled to an electrode assembly, and repeatedly per second generating electrical pulses having an energy level in the range of 10-500 Joules to create a plasma channel within or on the surface of the body of material, thereby causing material to fracture and fragment from the body due to the rapid expansion of each plasma channel following electrical breakdown of the material.
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39. An apparatus for removal of material from a body of material, the apparatus comprising a high voltage pulsed generator coupled to an electrode assembly located at a material-removal station of said apparatus, said apparatus being adapted to generate electrical pulses to create a plasma channel repetitively per second within or on a surface of the body of material and material is removed by the rapid expansion of each plasma channel fracturing and fragmenting the body of material, wherein the pulse generator produces a high voltage pulse which has a current waveform close to that of the critically damped response of the circuit created when the plasma channel is produced.
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40. An apparatus for removal of material from a body of material, the apparatus comprising a high voltage pulsed generator coupled to an electrode assembly located at a material-removal station of said apparatus, said apparatus being adapted to generate electrical pulses to create a plasma channel repetitively per second within or on a surface of the body of material and material is removed by the rapid expansion of each plasma channel fracturing and fragmenting the body of material, wherein the electrode assembly is in the form of a sonde and the high voltage pulsed generator an electrical cartridge, thereby enabling the sonde and cartridge to be deployed down-hole in a well or bore by means of coiled tubing, drill pipe, wireline or the like.
Specification