SU1441340A2 - Pressure pulse source with variable frequency spectrum - Google Patents

Abstract

The invention relates to seismic excitation devices. oscillations during geophysical investigations to electrical discharge in a fluid. The purpose of the invention is to increase 71 seismic efficiency by expanding the frequency spectrum of the emitted signal. The device contains a shock generator 1, a transformer 2 with a low-voltage winding 3 and two high-voltage windings 4, high-speed switches 5 and 6, an electric-discharge converter, the power supply of which includes a current sensor, the output of which is connected to the input of a linear amplifier with dead zone, and the output of the latter is included in the control circuit of a high-speed switch 6 connected to an electric discharge converter circuit. 2 Il. a AND 9 b / 4; with 4 About MS)

Description

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The invention relates to devices for exciting seismic vibrations during geophysical surveys by electrical discharge in a liquid.

The purpose of the invention is to increase the seismic efficiency of the fumes by expanding the frequency spectrum of the emitted signal.

Figure 1 shows the circuit diagram of the source described; figure 2 - current pulses in the electric discharge of the Converter.

The source with a controlled frequency spectrum of pressure pulses contains: shock generator 1, high-voltage pulse transformer 2s with low-voltage winding 3 and high-voltage windings 4, high-speed switches 5 and 6, electric discharge converter 7, which has electrodes - two extreme 8 and one middle 9, the peaking capacitors 10, the current sensor 11, the linear amplifier 12 with the dead zone and a control unit (not shown).

The device works as follows.

In the initial state, the switch 5 is open, and the switch. 6 closed. Impact generator 1 is excited to the nominal voltage and operates in idle code mode, since the distance between the electrode head of the electric discharge converter 7 is chosen such that the voltage of the generator 1 is insufficient for the inter-electrode gap breakdown,

When the voltage of the generator 1 passes through zero to a positive half-wave, switch 5 triggers and closes the stator winding to the low-voltage winding 3 of transformer 1, which allows to obtain the maximum value of the short-circuit shock current of the shock generator 1. Transformer ratio 2 is selected such that The EMF values of the high-voltage windings 4 are sufficient for breakdown of the interelectrode gaps of the electric discharge transducer 7s. During the breakdown of the interelectrode promazhut ™ of the electric discharge transducer 7 nergi to the arc discharge is supplied from both exacerbated kschih containers 10, and with the high-voltage windings 4 Shaper 2. Energy Release in

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The arc discharge from the capacitances 10 contributes to a more rapid decrease in resistance in the interelectrode gaps of the electric discharge converter 7. At a given point in time, the switch 5 produces an open stator winding - low voltage winding 3 of the transformer 2, the current of which is transferred to the stator winding - electric discharge converter 7 The current sensor 11, installed in the power supply circuit of the electric discharge converter 7, generates a signal proportional to the current of the solar-discharge converter 7. This signal is supplied to the input of the linear amplifier 12 with the dead zone, and when the current reaches a predetermined value at the output of the linear amplifier 12 (an output voltage is generated, which enters the control circuit of switch b, which de-energizes the circuit of the electric discharge converter 7, after a pause depending on the number and pulses in the load (electric discharge converter), the switch 6 is closed and the duty cycle is repeated in the sequence THj described above.

The current pulses in the load are presented in Fig. 2. The number of pulses and, the duration of the pauses t are set by the operator and processed by the control unit. The amplitude of the current pulses I j, regul1) is given by changing the value of the dead zone in the linear amplifier 12, Taki. pattern (5 envelope of several short igulz gaps along a-shlitudvg will be DIRECT-S1 F1PZ LHC

pressure, which increases the resolution of the location of geological sections.

Claims (1)

Invention Formula Source with controlled frequency spectrum of pressure pulses according to aut. St. 744400J, in order to improve. seismic efficiency by spreading the 1airen-1 frequency spectrum of the radiated signal, a linear amplifier with an adjustable dead band and a sensor, are introduced into the power supply circuit of the electric discharge converter. ka output of which is connected to the input .. t44l340 a linear amplifier with an adjustable stdut switch, deadband, the output of an electric discharger, which is in tteiTb, is connected to the bypass control circuit.  tK.2 2U1