Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42D—BLASTING
  • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
  • F42D1/04—Arrangements for ignition
  • F42D1/045—Arrangements for electric ignition
  • F42D1/05—Electric circuits for blasting

Definitions

• the invention relates to a method for triggering detonators over a long length line according to the preamble of the first claim.
• Drilling for the exploration and exploration of oil and gas fields extends over lengths that, in particular horizontally, already extend far beyond 10,000 m.
• the borehole is usually perforated at several predetermined locations in order to allow, for example, the oil to enter the borehole.
• suitable explosive charges are positioned at the intended locations, which are detonated in a predetermined sequence using detonators.
• Several igniters in series are also ignited via a common line. Such a
• Ignition circuit is known for example from EP 0 588 685 B1.
• the detonators are controlled individually and then triggered.
• the ignition signal consists of an information component for addressing and unlocking the individual detonators and an energy component that triggers the ignition.
• Known electronic detonators require an unlocking sequence which consists of polarity changes in the nominal voltage which is present at the output of the detonator release device. In addition to the number of changes, the time between changes in the unlocking sequence is evaluated. This code is only accepted by the electronic detonator if the number of polarity changes is correct within a defined time and the slope of the polarity changes is defined.
• the voltage level can be so low and the signals of the transmitted data can be so distorted that the detonator does not recognize the signals and no ignition is triggered becomes.
• the distortion of the signals is primarily caused by the lack of edge steepness between the polarity changes in the nominal voltage.
• the cause of these faults lies in the capacitive and inductive behavior of the long line and the consumers upstream of the detonators, such as the feed drive of the drill head in the horizontal direction, its protective relay, the auxiliary tools and the positioning device. These consumers are supplied with energy via the same line through which the detonators are triggered. When the supply voltage is switched off and the signal and ignition voltage are switched on for data transmission or triggering of the detonators, the discharging capacities of the consumers are charged by this voltage. The result is a voltage drop and therefore a signal weakening.
• the effects of the capacitive resistances on the signals of the detonator release device are reduced in that, before the detonator is triggered, a DC voltage is applied to the line to the detonators, with which the capacities of the consumers are charged to such a level that the subsequent generation the signals for triggering the detonators no longer have any effect on the capacities of the consumers.
• the capacities of the consumers are discharged again after being charged, but the previous charging to a high level ensures that, at least until the last detonator is triggered, there is no charge due to charge losses Capacities. As a result, the nominal voltage required to generate the signals does not drop below their required level.
• the applied DC voltage is higher than the nominal voltage for generating the signals.
• the nominal voltage is 24 volts
• a voltage of 28 volts DC can be provided to charge the capacitors.
• a corresponding time can be provided in which the increased voltage is applied. In the example provided, an activation period of about 5 seconds would be advantageous.
• the increased voltage is below a critical voltage that can cause an igniter to trip.
• the detonators are generally designed so that they are resistant to a certain extent beyond the nominal voltage that is provided for generating the signals for triggering an detonator, without triggering. According to the invention, however, the intended tolerance range is not exhausted in order to avoid any risk, on the other hand, the level of the voltage is chosen so that the intended charging of the capacities of the consumers is possible within a very short time.
• the capacitive resistances vary depending on the length of the line and the additional consumers placed in the borehole and connected to it, it is advantageous if the capacitive resistance is determined before the capacitors are charged and, depending on its size, the capacitance is used to charge the capacitors at least the required DC voltage is determined. This ensures that the critical value of the voltage for triggering an igniter is not exceeded.
• the DC voltage to be switched on can thus be individually tailored to the respective application.
• the line to the detonators with their additionally connected consumers is a resonant circuit with a low-pass filter effect due to the inductances and capacitances. The low-pass filter effect is influenced in particular by the capacitances.
• the critical frequency at which the low-pass filter effect occurs can be determined by determining the capacitive resistance. A suitable signal frequency is then selected in order to effectively exclude the low-pass filter effect. According to the invention, a frequency which is reduced to such an extent is chosen that the voltage rises again to the final voltage in each period. Furthermore, this voltage must be present at its nominal level for a predeterminable time until the next polarity change, so that the characteristic signal formation is maintained and the polarity changes are also recognized by the signal receivers of the detonator.
• FIG. 1 shows an equivalent circuit diagram of a borehole assembly with detonators and additional consumers
• FIG. 1 shows the conventional course of the signal and ignition voltage at
• FIG. 3 shows the course of the signal and ignition voltage according to the invention.
• a line 3 with two line strands 3a and 3b leads from the detonator triggering device 2 to the detonators 4a, 4b and 4c.
• the charges 5a, 5b and 5c to be ignited are assigned to them.
• the additional consumers are as ohmic resistors 6, inductive resistors 7 - o -
• Designated 10 is a circuit breaker with which the detonators 4a to 4c are separated from the wiring harnesses 3a and 3b while the other consumers are being supplied via the voltage source 9.
• a control device is designated, with which, as indicated by a ⁇ o line 12, the circuit breaker 10 can be operated.
• a further switch 13 is provided which, as indicated by the line 14, can be actuated by the control device 11.
• the circuit breaker 15 10 When the voltage source 9 is disconnected from the line 3, the circuit breaker 15 10 is closed and the voltage source 15 is connected to the line strands 3a, 3b without first generating signals for triggering the detonators for 4a to 4c. Then, in accordance with the present exemplary embodiment, the capacitive resistance and the voltage drop in line 3 are determined using a test device designated by 16, which is connected to lines 3a and 3b via lines 17 and 18. These values are transmitted via line 19 to the ignition trigger device 2. To charge the capacitors 8 of the consumers, a higher voltage is then applied from the voltage source 15 over a predefinable time than is provided for generating the signals for triggering the detonators.
• test device 16 can also be provided to determine the capacitive low-pass filter effect of the line 3 and the connected additional consumers on the basis of the capacitive resistance and to report it to the detonator triggering device 2, so that one of the capacitive resistance of the line and the Frequency matched to the consumer Potential change in the voltage for generating the signals for triggering the igniter is set.
• FIG. 2 shows the conventional course of a signal upon arrival at an igniter in a voltage-time diagram (U, t).
• a direct voltage of the voltage source 15 is applied from the igniter triggering device 2 to the line 3 in the amount U n + . It is the nominal voltage required to generate the signals.
• the signal sequence characterized by a change in polarity of the nominal voltage between the polarities U n + and U n-, begins with the frequency f. The duration of half a period is denoted by ti.
• the capacities of the consumers are charged before the signals are generated.
• the signal voltage no longer has to additionally charge the capacitors.
• the respective nominal voltage U n + or U n - is reached with each change in polarity.
• the frequency f e is reduced with respect to the low-pass filter effect compared to the original frequency f according to FIG. 2.
• the interval according to FIG. 2 is extended by a time t 2 .
• the voltage rises to the nominal voltage and is held at this level for a predefinable time t 3 before the next polarity change begins.
• the nominal voltage is actually reached in its full amount with each polarity change and is held at this level for a certain, predefinable time t 3 , it is possible for the igniter electronics to receive and identify the signals correctly.
• the invention thus enables a safe and interference-free signal transmission between the detonator triggering device and the detonators and thus ensures that each detonator is also triggered at the intended time.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Geophysics And Detection Of Objects (AREA)
• Air Bags (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1999
  • 1999-03-20 DE DE19912641A patent/DE19912641A1/de not_active Withdrawn
• 2000
  • 2000-03-02 DE DE50006500T patent/DE50006500D1/de not_active Expired - Lifetime
  • 2000-03-02 AT AT00920468T patent/ATE267382T1/de not_active IP Right Cessation
  • 2000-03-02 AU AU41039/00A patent/AU4103900A/en not_active Abandoned
  • 2000-03-02 WO PCT/EP2000/001821 patent/WO2000057124A1/fr active IP Right Grant
  • 2000-03-02 EP EP00920468A patent/EP1166037B1/fr not_active Expired - Lifetime

Non-Patent Citations (1)

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