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EP-4735728-A1 - A DRILLING EQUIPMENT AND A METHOD OF OPERATION

EP4735728A1EP 4735728 A1EP4735728 A1EP 4735728A1EP-4735728-A1

Abstract

The present disclosure relates to a method of operating a pulsed power drilling equipment (100) comprising a drill head (101), a liquid supply system (110), and a liquid retrieval system (120), the method comprising: - controlling the drill head to drill a hole (2) in a mineral substrate (1) in a drilling operation by passing a high voltage current pulse (5) through the mineral substrate, - controlling the liquid supply system to supply a liquid (3) to the hole during the drilling operation, - controlling the liquid retrieval system to retrieve the liquid from the hole during the drilling operation, wherein the liquid supply system and the liquid retrieval system are controlled such that a level (4) of the liquid within the hole is at a target level (h) set such that an upper portion (2a) of the drilled hole is free from the supplied liquid.

Inventors

  • JAKOBSSON, Erik
  • Merkel, Harald Franz Arno
  • SKYTTEDAL, André

Assignees

  • Epiroc Rock Drills Aktiebolag

Dates

Publication Date
20260506
Application Date
20230629

Claims (15)

  1. 1. A method of operating a drilling equipment (100) comprising a drill head (101) having at least two electrodes (102, 103), the drilling equipment (100) further comprising a pulsed power generator (150) for generating high voltage current pulses, a liquid supply system (110), and a liquid retrieval system (120), the method comprising: controlling (S1) the drill head to drill a hole (2) in a mineral substrate (1) in a drilling operation by passing a high voltage current pulse (5) generated by the pulsed power generator (150) between the at least two electrodes (102, 103) via the mineral substrate (1), controlling (S2) the liquid supply system (110) to supply a liquid (3) to the hole (2) during the drilling operation, controlling (S3) the liquid retrieval system (120) to retrieve the liquid from the hole (2) during the drilling operation, wherein the liquid supply system (110) and the liquid retrieval system (120) are controlled such that a level (4) of the liquid (3) within the hole (2) is at a target level (h) or within a target range (h1-h2) during the drilling operation, the target level (h) or target range (h1- h2) being set such that an upper portion (2a) of the drilled hole (2) is free from the supplied liquid (3).
  2. 2. The method according to claim 1 , wherein the liquid supply system (110) comprises a liquid supplying pump (111), and wherein controlling the liquid supply system (110) such that the level (4) of the liquid within the hole (2) is at the target level or within the target range comprises controlling a flow rate of the liquid supplying pump (111).
  3. 3. The method according to claim 1 or 2, wherein the liquid retrieval system (120) comprises a liquid retrieving pump (121), and wherein controlling the liquid retrieval system (120) such that the level (4) of the liquid within the hole (2) is at the target level or within the target range comprises controlling a flow rate of the liquid retrieving pump (121).
  4. 4. The method according to any one of the preceding claims, wherein the drilling equipment (100) further comprises at least one sensor (130) or switch (131 , 132) arranged to detect the level (4) of the liquid (3) within the hole (2), and wherein the method comprises: detecting (S4) the level (4) of the liquid using the at least one sensor (130) or switch (131, 132), wherein at least one of the liquid supply system (110) and the liquid retrieval system (120) is controlled in dependence on the detected level (4) of the liquid (3).
  5. 5. The method according to any one of the preceding claims, further comprising: - varying the target value (h) or target range (h1-h2) during the drilling operation.
  6. 6. The method according to any one of the preceding claims, further comprising: detecting at least one crack (7) within a wall of the hole (2), in response to determining that the at least one crack (7) affects the level (4) of the liquid within the hole (2), adjusting the target value (h) or target range (h1-h2).
  7. 7. The method according to any one of the preceding claims, wherein the target value (h) or target range (h1-h2) is set such that said upper portion (2a) of the hole (2) being free from the supplied liquid (3) is a major portion of the hole (2).
  8. 8. The method according to any one of the preceding claims, wherein the drilling equipment (100) further comprises a gas supply system (630) and a plasma generator (620), and wherein controlling the drill head (101) to drill the hole (2) further comprises: controlling the gas supply system (630) to supply compressed gas to the plasma generator (620), controlling the plasma generator (620) to generate at least one plasma volume (610) extending from at least a first one (102’) of the electrodes (102, 103) to a surface (1a) of the mineral substrate (1) by ionizing the supplied compressed gas, wherein said pulsed power generator (150) is controlled to pass the high voltage current pulse (5) between the two electrodes (102, 103) via the at least one plasma volume (610) and the mineral substrate (1).
  9. 9. The method according to claim 8, wherein target value (h) or target range (hi — h2) is set to a value or range at which a maximum pressure caused by the liquid (3) within the hole (2) is smaller than a gas pressure of the compressed gas at an electrode outlet.
  10. 10. A drilling equipment (100) comprising: a pulsed power generator (150) configured to generate high voltage current pulses, a drill head (101) comprising at least two electrodes (102, 103), the drill head (101) being configured to drill a hole (2) in a mineral substrate (1) in a drilling operation by passing a high voltage current pulse (5) generated by the pulsed power generator (150) between the at least two electrodes (102, 103) via the mineral substrate (1), a liquid supply system (110) configured to supply a liquid (3) to the hole (2) during the drilling operation, a liquid retrieval system (120) configured to retrieve the liquid from the hole (2) during the drilling operation, and a control system (140) configured to control the liquid supply system (110) and the liquid retrieval system (120) such that a level (4) of the liquid (3) within the hole (2) is at a target level (h) or within a target range (h1-h2) during the drilling operation, the target value (h) or target range (h1-h2) being set such that an upper portion (2a) of the drilled hole (2) is free from the supplied liquid (3).
  11. 11. The drilling equipment according to claim 10, wherein the liquid supply system (110) comprises a liquid supplying pump (111), and/or wherein the liquid retrieval system (120) comprises a liquid retrieving pump (121).
  12. 12. The drilling equipment according to claim 10 or 11, wherein the liquid supply system (110) comprises at least one liquid supply conduit (113) having an outlet (114) at the drill head (101), and/or wherein the liquid retrieval system (120) comprises at least one liquid retrieval conduit (123) having an inlet (124) at the drill head (110).
  13. 13. The drilling equipment according to any one of claims 10-12, wherein the control system comprises at least one sensor (130) or switch (131, 132) arranged to detect the level (4) of the liquid (3) within the hole (2), and wherein the control system is configured to control at least one of the liquid supply system (110) and the liquid retrieval system (120) in dependence on the detected level (4) of the liquid (3).
  14. 14. The drilling equipment according to any one of claims 10-13, further comprising a plasma generator (620) configured to generate at least one plasma volume (610) extending from at least a first one (102’) of the electrodes (102, 103) to a surface (1a) of the mineral substrate (1) by ionizing a compressed gas, and a gas supply system (630) configured to supply the compressed gas to the plasma generator (620), and wherein said pulsed power generator (150) is configured to pass a high voltage current pulse (5) between the two electrodes (102, 103) via the at least one plasma volume (610) and the mineral substrate (1) to break the mineral substrate (1).
  15. 15. A drill rig (800) comprising the drilling equipment (100) according to any one of claims 10-14.

Description

A DRILLING EQUIPMENT AND A METHOD OF OPERATION TECHNICAL FIELD The present disclosure relates to rock drilling and handling of fluid during rock drilling. In certain aspects, it relates to a method of operating a drilling equipment. The disclosure further relates to a drilling equipment and a drill rig. BACKGROUND During rock drilling it is often necessary to supply a fluid towards the mineral substrate to be drilled. The fluid is sometimes referred to as a flushing fluid, and one of its functions is to remove rock debris from the drilled hole. In surface drilling operations, the fluid generally consists of a gas, such as compressed air. By flushing the hole with compressed air, rock debris is efficiently flushed out of the hole. Compressed air can easily be provided by means of a compressor. In underground drilling applications, a liquid instead of a gas is often used as the flushing fluid. The liquid, which may be oil or water, may in those cases be continuously pumped or ejected into the hole at high pressure, whereafter it is guided up from the hole via an annular cavity formed between a wall of the drilled hole and the drilling equipment used for drilling the hole. Liquid flushing is generally more energy efficient than compressed air and can hence contribute to lowering energy consumption at the drilling site. However, water or oil is usually a limited resource at the drilling site, and it is therefore generally desired to collect the used liquid and recirculate it into the hole. A problem that may arise when a liquid is used as the flushing fluid is that the liquid may diffuse into cracks extending from the drilled hole before it reaches the ground surface above the hole. This prevents efficient recirculation of the flushing fluid, which may be particularly problematic in regions without natural sources of liquid. SUMMARY A primary object of the present disclosure is to achieve an in at least some aspect improved method of operating a drilling equipment and an in at least some aspect improved drilling equipment. In particular, it is an object to achieve a method and a drilling equipment which facilitate the use of a liquid as a flushing fluid, also in surface drilling operations. According to a first aspect of the disclosure, a method of operating a drilling equipment according to claim 1 is provided. The drilling equipment comprises a drill head having at least two electrodes, a pulsed power generator for generating high voltage current pulses, a liquid supply system, and a liquid retrieval system. The method comprises: controlling the drill head to drill a hole in a mineral substrate in a drilling operation by passing a high voltage current pulse generated by the pulsed power generator between the at least two electrodes via the mineral substrate, controlling the liquid supply system to supply a liquid to the hole during the drilling operation, and controlling the liquid retrieval system to retrieve the liquid from the hole during the drilling operation. The liquid supply system and the liquid retrieval system are controlled such that a level of the liquid within the hole is at a target level or within a target range during the drilling operation, the target level or target range being set such that an upper portion of the drilled hole is free from the supplied liquid. By the proposed method, it is possible to concentrate the liquid to a lower portion of the hole, where the drill head is located, while the upper portion is kept dry during the drilling operation. This means that seepage, or leakage through cracks in a wall of the hole, can be reduced thanks to the smaller portion of the hole being exposed to the liquid. An improved recirculation of the liquid can hence be achieved. In this way, advantages associated with using a liquid flushing fluid instead of a gaseous flushing fluid such as compressed air can be achieved even when the supply of liquid, such as water, oil, or emulsion, is limited. Such advantages may include reduced energy consumption, less dust, and a better stability of the drilled hole. The method may in some embodiments be carried out at least in part by an electronic control unit comprising processing circuitry. In some embodiments, the method may at least in part be carried out by a control system comprising switches configured to automatically switch the liquid supply system and the liquid retrieval system on and off in dependence on the level of the liquid within the hole. The target level or target range may be measured from a bottom of the drilled hole. The drilled hole may extend downward, such as in a vertical direction or in a slanted direction. The upper portion of the hole is to be understood as the portion of the hole which is closest to a surface of the mineral substrate in which the hole is formed, i.e., the surface relative to which the hole is defined. Optionally, the liquid supply system comprises a liquid supplying pump, and controlling the liquid supply