SU813349A1 - Device for graduation and testing acoustic logging instruments - Google Patents

Description

   G.

The invention relates to a geophysical measuring technique and can be used for the calibration and calibration of acoustic logging equipment designed to measure the time of propagation and attenuation of acoustic signals.

It is known a device for calibing a acoustic logging instrument, in which the waveguide of acoustic waves is made in the form of a metallic elastic tape, the portions of which in the zones of electroacoustic transducers of the instrument being calibrated are uniquely fixed in the fluid medium by the unit for orientation 1.

A disadvantage of this device is the impossibility of calibrating and calibrating the equipment throughout the whole scale of the measurement range.

The closest to the present invention is a device containing a receiver and emitters of acoustic signals, an amplifier, a threshold device, blocks of calibrated pulse delay, amplifiers, limiters and calibrated attenuators. In this device, the receiver and the calibration device emitters are pressed against the emitter and receivers of the downhole tool of the equipment being tested, as a result of which the acoustic pulse of the downhole device radiator is converted by the receiver of the calibration device into an electrical pulse that is delayed in blocks of delay for a calibrated time, amplified by the limiting amplifier and transmits 0 s through calibrated attenuators to a measuring device emitters that directly affect reception iki skvazhinnog.opribora power metal emoy apparatus 2.

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The disadvantage of this device is the impossibility of reproducing the attenuation measure of acoustic waves with a high degree of accuracy due to the instability of the level of acoustic contact between the radiators of the testing device and the receivers of the downhole tool,

The purpose of the invention is to improve the reproduction accuracy of the attenuation measure of the acoustic signals of a device for calibration and calibration of acoustic logging equipment. The goal is achieved by inserting a pipe into the device,

0 filled with fluid on the outside

To the side of which acoustic signal emitters are placed (for example, ring-shaped, magnetostriction ones that have a hard contact with the pipe (for example, using a compound). The reproduction accuracy of the attenuation measure of acoustic waves in this device is increased by ensuring the stability of the acoustic contact between the radiators of the testing device and the receiver equipment.

The drawing schematically shows the structure of the device for the calibration and calibration of the acoustic logging equipment of the structure and 1 P 1 P 2 and its principle of operation.

The calibrated equipment consists of a downhole tool 1 containing the radiator 2 and receivers of the 3rd 4 acoustic signals, the logging cable 5 and the ground measuring panel 6, the output signals from which are fed to the logging recorder 7. The device for marking and calibrating the acoustic logging equipment contains a pipe 8 with radiators 9 and 10 of acoustic signals rigidly coupled with it, filled with liquid 11, centralizers 12 and 1 receiver 14 of acoustic signals, threshold device 15, blocks 16 and 17 of the calibrated delay, generation Op 18 emitter excitation pulses, control unit 19, switch 20 and sources 21 and 22 calibrated voltages, /

The device works as follows.

The acoustic impulse of the radiator 2 of the downhole tool 1 is converted by the receiver 14 into an electrical impulse that triggers the threshold device 15, the threshold device generates a pulse that triggers the blocks 16. and 17 of the calibrated delay, which form the pulses of calibrated duration. Block 16 generates a pulse of duration t, block 17 - t, Output pulses of blocks 16 and 17 are fed to a bushing 20, which passes one pulse of these pulses to the input of generator 18 of radiator excitation pulses. The switch state is determined by the signal of control block 19 of the ground measuring panel 6 of the test equipment AK. During the first half-cycle of measurement of the test equipment, when the parameters of the signal from the receiver 3 are measured, the switch 20 is in the state shown in black , during the second half-cycle of measurement, the moving contacts of the switch change their position to the opposite. On the first half-cycle of measuring the measured equipment, the generator 18 of the excitation pulses is started with a delay C relative to the starting time of the radiator 2, in the second half-cycle the measurement is delayed t. In this case, in the first case, the emitter 9 is excited by a pulse of calibrated amplitude, which is determined by the source of 21 calibrated voltages, and in the second case, the emitter 10 is excited by a pulse of calibrated amplitude,

defined by source 22,

The acoustic pressure generated by radiators 9 and 10 through the material of the pipe 8 and the liquid 11 affects respectively the receivers 3 and 4 of the downhole tool 1,

Thus, in each measurement cycle of the calibrated equipment, the calibrated values of the interval propagation time, At, of the attenuation coefficient, Ig, are specified; acoustic signals, where A and A, 2 are the amplitudes of the acoustic pulses, respectively, at receivers 3 and 4 of the downhole tool 1. The readings of the equipment being checked are recorded by a logging recorder 7 and compared with calibrated At values and about, reproducible calibration device. The conversion factors of the calibrated voltage generated by the sources 21 and 22 into the amplitudes A and A of the acoustic pressure pulses are determined by metrological certification of the device using an exemplary hydrophone centered along the axis of the pipe 8, alternately opposite the emitters 9 and 10. generated by the sources 21 and 22, the amplitudes of the sound pressure pulses, respectively, A and AQ, are matched

Similarly, a calibration calibration device can be implemented for an acoustic logging instrument with a greater number of receivers.

Improving the accuracy of the calibration and calibration of acoustic logging equipment improves the accuracy of the calibrated equipment when measuring the attenuation of acoustic waves in the mined rocks, which increases the efficiency of using acoustic logging equipment for well testing.

Claims (2)

1. Authors certificate of the USSR 518749, cl. G 01 V 1/40, 1976. 2. US Patent 2,944,621, cl. 181-5, I960 (prototype).