SU1053036A1 - Method of calibration testing of acoustical logging equipment - Google Patents

Abstract

METHOD OF TESTING THE DEVICE OF ACOUSTIC CARROLLS, based on the excitation of the emitter of the borehole device from the reference clock pulses and measuring the amplitude and running time of an elastic wave in a conductive medium, due to the fact that, in order to monitor the accuracy of the instrument's calibration, it is accurate to check the accuracy of the instrument. logging, for each measurement channel, additional sync pulses are generated, delayed relative to the reference sync pulses by calibrated time values, and in each measurement cycle, additional sync pulses are triggered pulses measuring channels of the ground part of the equipment.

Description

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The design reference relates to geophysical field research. wells, and more specifically to the methods of calibration of acoustic logging equipment.

The known method of calibration of acoustic logging equipment is based on the measurement of acoustic parameters in a metal pipe, and when the device is lowered into the well, the pipe is pulled over the electrode part of the equipment and, at any depth in the well, the equipment can be checked using a standardization pipe, i.e. the basic error of measurements of interval time and attenuation at one measurement point 1 was determined,

The disadvantage of this method is the impossibility of carrying out the verification over the entire measurement range and, therefore, the impossibility of determining the working range of the equipment being scanned. .

The closest to the present invention is a method of calibration of acoustic logging equipment, based on the excitation of the emitter of the borehole device from the reference sync pulses, measurement of the amplitude and travel time of the elastic wave in a sound-conducting medium. In this method of calibration, the downhole tool is installed in a homogeneous sound-conducting medium; in the first measurement cycle, the first radiator of the device is excited from the reference clock pulses of the first measurement channel and the parameters are recorded. elastic waves propagating in a sound-conducting medium from this radiator, in the second measurement cycle, the second radiator is turned off, and the first radiator is again excited instead, but the moment of its excitation is delayed relative to the reference sync pulses of the second measurement channel by a calibrated value, and the amplitude of elastic oscillations of this The emitter in the second measurement cycle is changed to calibrated values relative to its amplitude in the first measurement cycle 2.

The disadvantage of this method of verification is a decrease in the accuracy of equipment calibration due to the fact that one of the emitters does not participate in calibration and the systematic measurement error, depending on the base length error, is not taken into account for the interval time. On the other hand, the systematic error associated with measuring the attenuation coefficient due to the difference in the emitter intensities is not taken into account. Instrument calibration accuracy is also reduced due to the influence of downhole conditions on the electronic circuit of the calibration system. In addition, the measurement scheme of the downhole tool that implements this method is complicated. The implementation of the method is possible only for a three-element probe.

The purpose of the invention is to improve the accuracy of the calibration of acoustic logging equipment.

This goal is achieved by the fact that according to the method of calibration of acoustic logging equipment, based on the excitation of the emitter of the downhole tool from the reference sync pulses and measuring the amplitude and travel time of the elastic wave in a sound-conducting medium, for each measurement channel form additional sync pulses delayed relative to the reference sync pulses to the calibrated , time values, and in each measurement cycle, the measurement channels of the ground part of the appr are triggered by additional sync pulses. ture.

Improving the accuracy of verification is achieved due to the fact that the systematic error of the interval time measurements is taken into account, which arises due to the inaccuracy of the dimensions of the probe base, as well as the error in measuring the attenuation caused by the difference in the intensity of the emitters, since in this case they both participate in checking

FIG. 1 shows a scheme for carrying out the method / FIG. 2 - examples of additional sync pulses for two and three element probes.

The downhole tool 1 is placed in a device containing a sound-conducting medium with known acoustic properties in the form of a pipe 2 filled with liquid, while the downhole tool is connected by cable (or cable simulator) 3 to calibration block 4 and further to ground panel 5 and recording block 6.

The method is carried out as follows.

When calibrating the instrumentation of the borehole device 1, the device 1 is installed in a sound-conducting pipe 2 with known acoustic properties and a standardized signal from the output of the borehole device and sync pulses determining the moment of excitation of the device emitters through the cable 3 or imitated cable enters the certified calibration block 4, powering the downhole tool performed from the ground panel 5 via cable 3 or an imitated cable. In block 4 calibrations, the clock pulses are discretely or continuously delayed by calibrated values, and the amplitude of the standardized

the acoustic signal is changed to calibrated values. The delayed sync pulses and the calibrated acoustic signal from the output of the calibration unit arrive at the ground channel 5 of the equipment being checked, and the output signal of the ground panel 5 is recorded by any known method, for example, by a certified logging logger.

When calibrating equipment with a two-element probe, the downhole tool is placed in a pipe filled with liquid, for example, vinyl plastic or any other material that allows the device to fix the minimum signal, then the running time of the elastic wave recorded by the recording device at the exit of the ground panel 5 will be maximum t tiMQiKc. When changing for-. holding the sync pulse for a given calibrated value, the fixed time will vary according to the specified calibrated delay values, and (4

When calibrating equipment with a three-junction: ment probe, the downhole tool is placed in a pipe filled with a liquid (for example, steel). Then the travel time of the elastic wave, fixed by the recording device at the exit of the ground panel, will be minimal for a large probe as well.

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t, 6 C, d ,, „. Registered standardized time L -o MMM. PR of the sync pulse delay (The specified calibrated values for the small probe channel, the interval time changes in accordance with the change of the calibrated values of the delay times and corresponds to ftti btp - t k;;

The proposed method of calibration of acoustic logging equipment in comparison with the known method has the following advantages; possibility of calibration of acoustic logging equipment with two- and three-element probes and an increase in accuracy of calibration.

Claims (1)

METHOD FOR TESTING ACOUSTIC LOGGING EQUIPMENT, based on the excitation of a downhole tool emitter from reference clock pulses and measuring the amplitude and travel time of an elastic wave in a sound-conducting medium, with the aim of increasing the accuracy of calibration of acoustic logging equipment , for each measurement channel, additional clock pulses are generated, delayed relative to the reference clock pulses by calibrated time values, and in each measurement cycle, additional clock pulses are triggered and measuring channels are land part of the apparatus. fs f eeodeot I 1053036.2