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
  • E21B44/00—Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
  • E21B44/02—Automatic control of the tool feed
  • E21B44/06—Automatic control of the tool feed in response to the flow or pressure of the motive fluid of the drive
• • 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
  • E21B44/00—Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
  • E21B44/02—Automatic control of the tool feed
  • E21B44/08—Automatic control of the tool feed in response to the amplitude of the movement of the percussion tool, e.g. jump or recoil

Definitions

• the present invention relates to a method and system for controlling drilling parameters during an initial phase of drilling into a rock.
• the critical part of the drilling i.e. the start-up or so called collaring
• the critical part of the drilling should be smooth and careful until there has been formed a deep enough hole having a correct direction, whereafter full feed force and drilling power may be utilized. What constitutes a deep enough depth depends to a large part on the quality of the rock. For example, soft rocks having many cracks may require a deeper hole to ensure a correct direction, before full feed force is used.
• the transition step should be smooth, but not unnecessary extended in order to avoid that time is lost because a great part of the hole is drilled at a lower power than the available full power. Consequently, the parameters that have to be set constitutes a considerable drawback of the method shown in EP 0 564 504.
• There are a number of parameters to adjust for each of the three or more stages for example, different periods of time, percussion force, feed force, drilling time, drilling depth, speeds etc.
• discontinuities in the direction of drilling parameter increase may give incorrect information to those parts of the automatic control system that supervise these parameters in order to detect a drill possibly getting stuck.
• the above mentioned objects are accomplished by a method for controlling drilling parameters during an initial phase of drilling in rock using a drilling machine, whereby the percussion pressure and feed pressure of the drilling machine are controlled as continuously increasing functions during the initial phase.
• the number of parameters can be minimised to include start values for the percussion and feed pressure, and time duration of the initial phase. Further, a successful drilling is ensured by adjusting the collaring depth by means of the duration of the initial phase.
• the initial phase thus includes a single stage control starting from predetermined start values to full force values. This results in a time efficient initial drilling, wherein the time to set different parameters in a plurality of different stages has been eliminated .
• control is represented by functions, which are continuous in time and having a gradually increasing derivative.
• said continuous functions are represented by exponential functions.
• a well known mathematic function may which can easily be programmed and stored.
• the feed pressure is supervised during the collaring stage, so that the percussion pressure is limited if the damping pressure with certainty does not exceed the idling pressure of the damper.
• This supervision may, for example, be performed by means of a RPCF function (Rotation Pressure Controlled Feed) , and the percussion pressure values may, in a preferred embodiment, be limited to the percussion pressure start values.
• the percussion pressure may be lowered when the feed pressure goes below a predetermined level .
• the present invention is also related to such a system, by means of which advantages similar to the above described is achieved.
• Figure 1 shows a timing diagram of a prior art method for collaring .
• Figure 2 shows a timing diagram of another prior art method for collaring.
• Figure 3 shows a timing diagram of a method for collaring in accordance with the invention.
• Figure 4 schematically shows a system in which th vention may be utilised.
• This method comprises a number of parameters that has to be set. Initial values have to be determined, and, also, for how long this stage with reduced power is to go on. Further, the aspects of the transition stage illustrated in figure 2, between the points Tl and T2, have to be determined. In other words, it has to be determined what the transition step should look like in order for it to be smooth enough. At the same time it is undesired to drill with the reduced power too long, since time then is lost.
• start values for the percussion pressure of the drilling machine (and thereby the percussion power of the drilling machine) , and the feed pressure are chosen. These values are chosen such that the collaring is smooth enough to ensure that the hole obtains correct direction and position, while at the same time the pressure cannot be so low that it may cause problems in the drilling machine.
• start values are advantageously chosen to be slightly higher than the accumulator pressure in order to avoid problems with included membranes.
• the start values should, off course, neither be too low to accomplish a collaring hole.
• the start values may, for example, in an ordinary drilling machine, be about 130 bar.
• the initial phase, or collaring phase is then controlled by continuously increasing functions.
• the continuously increasing functions have a gradually increasing derivative, as is shown in figure 3, which results in the preferred, smooth transition.
• a function which advantageously may be used, is the mathematically well known exponential function, but any substantially continuous function in accordance with the mentioned requirements may be used.
• the use of a continuous function of time with a gradually increasing derivative results in a system with only two control stages, of which the parameters of the first stage, the collaring, includes the start values of the percussion pressure, the feed pressure and the length of the initial st Thereby, the number of parameters needed to be set mised.
• the percussion pressure and feed pressure are controlled independently, but with the same duration, i.e. throughout the collaring stage.
• the feed pressure should, however, be supervised by means of the system RPCF function (Rotation Pressure Controlled Feed) during the collaring stage.
• the RPCF function controls the feed pressure such that the rotation pressure and/or torque is substantially constant in order to ensure that the drill string component joints are suitably tightened. This function is of particular importance during full drilling, when the power is higher.
• the damping pressure of the drilling machine should be supervised so that the percussion pressure is limited to, for example, the start values if the damping pressure with certainty does not exceed the no-load pressure of the damper.
• the damper is used to damp the reflexions which arise when the drill steel hits the rock.
• the damping pressure may be used to ensure that the drill steel is in contact with the rock at time of percussion.
• the initial stage may, in other words, be combined with the supervision of the damping pressure so that the percussion pressure does not run away from the feed pressure.
• the accumulator pressure it is not always necessary to go down to the start values, even if this usually is the case since these have been chosen with regard to, among other things, the accumulator pressure.
• the risk for self- oscillation is avoided in the system. Accordingly always necessary to go down to the lowest level i: ing, i.e. the start values, if soft rock is encountered, but it is possible to go down to a level where the percussion pressure is limited with regard to the no-load pressure of the damper. Alternatively, the percussion pressure may be lowered when the feed pressure is or goes below a predetermined level.
• An operator may chose between the setting of a desired hole depth of the collaring, or for how long the initial phase should go on.
• stop values may also be determined, which advantageously correspond to the full power of the drilling machine. It may, however, in some situations, be necessary to run the machine at a reduced power, whereby desired values may be set.
• FIG 4 schematically shows a system 1, in which the present invention may be utilised.
• the system 1 includes, in its simplest embodiment, a drilling machine 2 with a control system 3, by means of which an operator may control the system 1.
• the control system may be integrated with the drilling machine 2, or be separately connected.

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• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Earth Drilling (AREA)
• Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
• Peptides Or Proteins (AREA)
• Paper (AREA)
• Diaphragms For Electromechanical Transducers (AREA)

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• 2004
  • 2004-06-09 SE SE0401472A patent/SE528699C2/sv not_active IP Right Cessation
• 2005
  • 2005-05-31 ZA ZA200608971A patent/ZA200608971B/en unknown
  • 2005-05-31 CA CA2561894A patent/CA2561894C/en not_active Expired - Lifetime
  • 2005-05-31 US US11/578,868 patent/US7762346B2/en active Active
  • 2005-05-31 JP JP2007527130A patent/JP4759566B2/ja not_active Expired - Lifetime
  • 2005-05-31 WO PCT/SE2005/000819 patent/WO2005121506A1/en not_active Ceased
  • 2005-05-31 DE DE602005003371T patent/DE602005003371T2/de not_active Expired - Lifetime
  • 2005-05-31 AT AT05746886T patent/ATE378502T1/de active
  • 2005-05-31 AU AU2005252606A patent/AU2005252606B2/en not_active Expired
  • 2005-05-31 CN CN2005800137130A patent/CN1950586B/zh not_active Expired - Lifetime
  • 2005-05-31 ES ES05746886T patent/ES2293580T3/es not_active Expired - Lifetime
  • 2005-05-31 EP EP05746886A patent/EP1766186B1/en not_active Expired - Lifetime

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