WIEKAMP JAN HENDRIK ATE (NL)
| WO2003069110A1 | 2003-08-21 |
| US20090200032A1 | 2009-08-13 | |||
| US5168940A | 1992-12-08 | |||
| US3467206A | 1969-09-16 |
| Claims: 1) Drilling, excavating or mining using thermal spallation technology extracting power from pumped drilling mud to drive a generator for electrical power for an electrical arc where energy is extracted from the arc under formation of a plasma jet, to create a heat flux towards a rock formation to spall the rock, where the plasma forming gas is generated underground by water or steam, or gas from a chemical reaction between water, drill fluid, or from drill fluid extracted water, and a solid, like sodium, potassium or calciumcarbide, where the plasma forming gas contains hydrogen, like in steam or acetylene, and where 50% or more of the atoms in the plasma are hydrogen atoms. 2) Drilling, excavating or mining using thermal spallation technology extracting power from pumped drilling mud to drive a generator for electrical power for an electrical arc where energy is extracted from the arc under formation of a plasma jet, to create a heat flux towards a rock formation to spall the rock, where the plasma forming hydrogen and/or oxygen is generated underground by electrolysis of a brine, and where 50% or more of the atoms in the plasma are hydrogen atoms. 3) A combination of methods of claim 1 or 2 where water for electrolysis or chemical reaction is extracted from the drill fluid by osmosis from a brine saltier than the drilling fluid. 4) A combination of the methods of claim 1,2 or 3 integrated in a drill head, where the rotation of the drill head creates a thermal cycle of heating and cooling parts of the rock, by which the rock weakens or spalls, where the plasma jet, from 1 or more plasma generators, follows a circular path and locally heats the rock, where after passing of the plasma jet, the drill fluid quickly cools the rock, creating mechanical stresses or weaknesses in the rock. 5) A combination of the methods of claim 1, 2, 3 or 4 integrated in a drill head with fixed bits or teeth, like a standard PDC Polycrystalline Diamond Compact, to thermally weaken the rock or create micro fractures in it, so the bits or teeth can more easily grind the rock. 6) As any one of claims 1 to 5, where part of the plasma forming gas, like hydrogen, is captured after being expelled by the plasma generators, and reused. |
Technology
The invention is to be used for drilling, excavating or mining.
Objects of the Invention
A drilling technology for hard rock, replacing or complementing mechanical drilling, needing no adaptation to standard drill pipe or need to pump down fuel, using down-hole generation of gas and electricity, using thermal cycling with plasma generators to weaken or break rock, and compatible with standard drill bits and hydraulics .
Background of the Invention
Standard drilling technology uses mechanical grinding, which as best is slow in hard rock and wears out drill-bits fast.
Geothermal drilling using hot air spallation was developed in the 1970s, and demonstrated impressive drilling performance, producing 8 inch to 12 inch boreholes to depths of 1,100 feet at rates faster than 50 feet per hour in solid granite. But to get spalls out from deeper wells, a fluid has to be circulated, which is incompatible with the hot air technology. Also pumping down fuel and oxidizer is incompatible with using standard drill pipe, rotating drill bits, and standard drill rig operations including keeping within strict safety rules. Bringing down common plasma gasses like nitrogen, argon, oxygen or helium in pressurized containers is impractical and dangerous as well. Further, continuous heating can become highly ineffective when rock types are hit that will not spall rapidly , and might even melt, and block further drilling.
Proposed technology omits the need to transport down fuel or gas, as the plasma generating gas, like hydrogen, is generated down-hole either through electrolysis of a brine which extracts water through osmosis from the drilling mud or by a chemical reaction between water or mud and a solid, like sodium, which might become liquid at down-hole conditions. Electricity for the electric arcs and for electrolysis is generated by a down-hole turbine, and only a limited amount of gas has to be generated as most can be recaptured and reused, as the gas does not have to be burned, but is only used to extract heat from the electric arc, which dissociated the gas molecules into atoms which transport the arc energy, and releases recombination heat upon hitting the colder formation rock. The generation of hydrogen in the plasma is important to prevent oxidation and wear of the hot electrodes of the plasma generators, and should be above 50%. Integrating the plasma generators in a rotating drill-bit, the temperature shock is cyclic, and will increase fractures until the rock spalls.
No adaptation has to be made to the drill pipe, and the technology can be integrated with standard tri-cone or PDC drill bits, which can run in combination using the plasma generators to weaken the rock, so the teeth of the bits can now more easily grind spalls away out of the rock formation.
Description of the Drawing In Fig.l is shown a schematic of a BHA (bottom hole assembly), with (1) drill pipe through which drilling mud (2) is pumped from the surface. A turbine (3) is powered by the pumped mud, and drives a generator to power the electrolysis of a brine (5) with electrodes generating hydrogen (6) and oxygen (7). The brine (5) is replenished by osmosis with water from the mud (2). Alternatively a chemical reaction between water, and a solid like sodium, potassium or calciumcarbide could provide a plasma generating gas. The hydrogen, or other down-hole generated plasma gas, is pressured by a pump (8) and vented through an arc (9), the arc being powered by the electricity from the turbine. Vented gas can be recaptured and reused. Drill pipe (1) can be standard drill- pipe, and control can be by standard MWD (measure while drilling), like mud-pulse. The drill-bits can be standard drill-bits, like PDC or tri-cone, with full mechanical
functionality, adapted to accommodate the arcing electrodes and gas vents.
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