SU760009A1 - Seismic signal source - Google Patents

Description

The invention relates to devices for the excitation of seismic vibrations in geophysical studies by electro-hydraulic method by electric discharge in liquid - * bones in wells in special chambers on the surface, as well as in water areas for the purposes of marine exploration.

A seismic signal source ^υ is known, consisting of a percussion generator, a rectifier unit, a saturation throttle, a controlled switching device, an electro-hydraulic radiator and an auxiliary capacitor battery connected to an electro-hydraulic radiator parallel to the percussion generator M.

The capacitor battery is designed for electrical breakdown and the formation of the arc resistance of the water gap of the electro-hydraulic emitter and the spark stage. a discharge of such magnitude as to ensure reliable interception of the arc by a low-voltage shock generator.

Contribution to the arc channel energy auxiliary capacitor battery.

makes up all 2-3% of the energy that is 30

2

Toruy shock generator gives the arc. The pressure impulse developed by the device has a small burst at the leading edge with an amplitude corresponding to the discharge of the auxiliary capacitor battery. Subsequently, due to the slow influx of energy from the percussion generator into the arc, the pressure increase slows down due to the inductance of the generator winding, which leads to a failure on the front of the pressure pulse curve and a decrease in the main pulse amplitude. Another disadvantage of the known device is the need to have a complex additional initiating device - capacitor banks.

The closest in technical essence to the present invention is a source of seismic signals, consisting of a shock generator with the main low-voltage and auxiliary high-voltage stator windings, an electric-discharge converter and controlled switches [2].

The use of a shock generator with two windings allows you to use the advantages of low-voltage shock generators and abandon

complex additional devices to initiate discharge, more efficiently / • / 'Mo use stator bore.

However, the known device has the following drawback: the shape of the current in the circuit of the electric-discharge converter from the main winding of the percussion generator is sinusoidal. This determines a relatively / 'slow initial energy input ·' into the arc channel, which 'leads to a slow formation of a vapor-gas band. As a consequence, the amplitude of the developed pressure pulse decreases .... , ... .. ........ ................. \.,

The aim of the present invention is to increase the amplitude of the developed pulse pressure by increasing the initial rate of energy input by increasing the steepness of the initial front of the discharge current pulse and

...... increase it. amplitudes. _; .------- 7 The goal is achieved by

THAT the source reference is introduced by a capacitor battery and an additional 'comm. / tator, which are connected in parallel 7 'and are connected in series in. .. Chain _"h main low-voltage winding stato7 Figure 1 is a diagram of seismic signals .istochnika FIG 2 -..

Graphs of current arc discharge in the proposed device. ... 7.7,.:, ...

The device consists of a shock Τ '. · ”. ....... 'a generator 7 having the main low-voltage winding 1 and an auxiliary 7 high-voltage winding 2. Main'

low-voltage winding 1 is connected via a thyristor switch 3 and a saturation throttle 4 per electrical section ..... row. converter 5, and ...

'a capacitor is included in this circuit

battery 6, bristling bypassing ........ by the associated commutator 7 .. Parallel

on the electric-discharge converter ........ 5 auxiliary you- connected.

7 juice winding 2 through a switch (controlled discharger) \ 8.

The device works as follows. .

.7 ^{'in the} initial state switches

3, Ί, 8'r'azomknu / gy, the capacitor battery b is charged up to a certain voltage and _c0 , the shock generator when-; put into rotation and excited to the nominal emf.

When a control signal is applied to the switching device by a high 'voltage of the auxiliary winding 2. it is pierced' interelectrode. · The gap of the electric discharge transducer of the maker 5. With some delay

according to the time determined by the time of breakdown of the interelectrode gap, a control signal is supplied to the commun ........

a tapering device 3, and a working

windings of the 1st capacitor battery

b is connected to the initiated electric arc channel

35

40

45

50

760009 4 '

..... • • ^ • dzd _va ^ - _elya ς time of the control signal to the switch.

8 is set in such a way that the ’sign of the EMF of the generator is positive and the value of the EMF is close to the maximum

(0

.15

20

25

55

60

value.

The voltage of the capacitor bank is equal to or greater (in this case, the insulation of the generator winding must be calculated for voltage and co) of the amplitude of the generator EMF. Calculations of the discharge current of a shock generator with a capacitor battery made with the same energy but different initial voltages (from 2.5 to 10 kV). have shown that at high voltages, an increase in the “initial steepness” of the current is reached. arc and size reduction of the capacitor battery. This is especially important /

 for autonomous electrohydraulic devices mounted on a truck.

As an example, nafig. 2 shows the calculated curve of current 9 in the electric-discharge converter with the following parameters of the main winding of the shock generator, capacitor bank and interelectrode pro-.

inter-rush: inductance of the main winding! _ _g · = 19Ό μg, active resistance g _g = 0.006 Ohm, amplitude of the EMF of the main winding Et = 2.5 kV, capacitance -... capacitor batteries C = 100 MkF, initial voltage 1) _c0 = kV, .-. energy \ ^ _c0 = 50 kJ, the length of the interelectrode gap V _e - 0.01 m.

For comparison, in this same figure. . The current curve 10 is shown when there is no capacitor battery in the working circuit, obmbtki. "The initial steepness of the leading edge of the current pulse, determined by the tangent to the current curve, drawn from point 1 = 0, increased in the proposed invention by 4 times compared with prototype. The calculations were made taking into account the nonlinearity of the arc channel resistance by the numerical Runge- ^ KutTe on-CMV M-222 method. · ··. The inclusion of the capacitor into the working circuit. The obturative generator leads not only as-amplitude-current pulse. this example, the current pulse amplitude is increased by 1.3 times compared with the prior art.

During the discharge process, the capacity begins to recharge. Therefore, when the voltage of the capacitor battery drops to zero, when the energy of the capacitor battery is completely transferred to the discharge circuit, it is short-circuited by the switch 7 (Fig. 1). The further input of energy to the electric-discharge converter comes from the percussion generator. ;

It is known that the amplitude of the pressure pulse 65 is defined as

five

energy introduced into the arc channel, and the rate of energy input. In both respects, the proposed device has significant advantages. Thus, for the considered example, the calculation showed that the amplitude of the pressure pulse increases by 80% compared with the prototype. .

Claims (1)

Claims 10 Source of seismic signals, consisting of a shock generator with the main low-voltage and auxiliary high-voltage windings of the stator, electric discharge transducer 760009 6 tel controlled switches, ό τη and h and y and i with the fact that, in order to increase the amplitude of the excited signal, the condensate is inserted into it. Sternary battery and additional switch, which are connected in parallel and connected in series to the main low-voltage winding of the stator.