SU181571A1 - DEVICE FOR SIMULTANEOUS DIMENSION OF MULTIPLE PARAMETERS AT DRIVING WELLS - Google Patents

Description

Apparatus are known for transmitting information in frequency division multiplexing and frequency modulated logging with modulating voltage detection.

The proposed device differs from the known ones in that it uses as a modulator a fantastic oscillator controlled by a low-frequency alternating current voltage, which is the measured signal.

This improves the accuracy of the required measurements.

The drawing shows a block diagram of the proposed device.

The power circuit of the borehole part of the telesystem and probe device is supplied from alternator 1 with frequency F. Current I feed from generator 1, passed separation capacitor 2 and choke 3 along the central conductor of the cable through choke 4 to power transformer 5 and then current electrode L probe

The reactive resistances of the chokes 3 vi 4 and the capacitor 2 are small for alternating current with a frequency F. If necessary, a measuring bridge of the rheostat sensor 6 is inserted between the power transformer and the current electrode A, for example, to measure the temperature in the well or the diameter of the well.

polarization of the rocks creates a direct current circuit. The potential difference of the PS between the electrode A and the electrode 7 on the surface is measured. The DC circuit is separated from the other circuits by means of capacitors 8, 2 and 9. The barrier filter 10 does not pass a supply voltage with a frequency F to the input of the PS channel. Together with the measurement of the potentials of the self-polarization of the rocks, the telesystem makes it possible to simultaneously register several other studied depth parameters. For each measured value, a frequency channel is created with frequency modulated carrier frequency, i.e., frequency division channels are used.

A variable voltage F is applied to the input of each channel from the corresponding sensor (from the measuring electrodes of the logging probe, rheostat temperature sensor, etc.).

The purpose of the individual functional units of the telesystem can be seen on the example of a single channel.

The measured potential difference between the electrodes M, NI is amplified by the amplifier and controls the frequency of the oscillator P. The frequency / 1 and the average load at its output varies according to the variation of the relative modulation of the carrier frequency fi. The carrier frequencies of each channel are mixed at the resistance 12, amplified by a common channel amplifier, and fed through a capacitor 8 to the central core of the cable. The carrier frequencies must be several times higher than the frequency F of the supply current, otherwise there will be difficulties in separating them.

The throttles 3 vi 4 perform high-frequency processing of the communication line.

On the surface, the high frequency information voltage of the first channel through the filter 13 is fed to the input of the frequency detector 14. The filter 13 passes the frequency band of the first channel with the center frequency i.

At the output of the frequency detector, an alternating voltage is obtained with a frequency F and an amplitude corresponding to the amplitude of the voltage being measured. The voltage detected by the detector is amplified by the amplifier 15 and rectified by the phase-sensitive rectifier 16. The output voltage of the phase-sensitive rectifier 16 is fed to the recording device 17 of the first channel and recorded on the diagram at a certain scale of the measured parameter.

The control voltage to the phase-sensitive rectifier 16 is obtained from the node 18, which allows to regulate the phase of the control voltage.

The reference phase can also be transmitted from the depth channel, introducing an auxiliary channel, which at the same time allows the control of the television system using a standard signal.

All other channels work in a similar way, including a channel with a rheostat sensor.

A power transformer 5 and a rectifier 19 serve to feed the incandescent and anode circuits of the subsurface circuit.

Improving the accuracy of measurements in the proposed device is achieved by eliminating the effect of changes in the supply current of the depth gauge on the measurement results.

It is known that the frequency of relaxation oscillations of a self-exciting fadron generator does not change while

a change in the significant limits of the control voltage supplied to the control grid of the lamp and the voltage of the anode power supply .. i (When using such a generator (//), its transfer characteristic will not change when the power current of the depth part of the tele system is changed. In the proposed frequency modulation of the carrier frequency / is carried out by alternating voltage with frequency F () taken from the measuring electrodes of the probe. The amplitude of this modulating voltage is determined by the value of the measured

parameter.

Due to the two-pole modulation of the carrier frequency f, the difficulties of transmitting a zero reading are overcome. In fact, in the absence of a modulating voltage with a frequency

F output of the tele system is zero regardless of the instability of the carrier frequency / generator of the frequency modulator or the instability of other functional units. The constant component of the signal is allocated only by the most recent functional unit — the phase-sensitive rectifier, and the circuit of the phase-sensitive rectifier assembled according to the key circuit has an insignificant zero zero.

Due to the above, the described device has a relatively high dynamic range (on the order of 1000), which allows the measured parameter to be recorded at the same time on three scales.

Subject invention

A device for simultaneous measurement of several parameters in single-core cable logging, containing a carrier frequency modulator, characterized in that, in order to improve measurement accuracy, a fadron generator controlled by alternating current AC, measuring, is used as a modulator emitted signal.

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