SU1015949A1 - Apparatus for reading out magnetic marks at measuring well depth - Google Patents

Abstract

A DEVICE FOR READING A MAGNETIC METHOD WHEN MEASURING A WELL DEPTH, contains a magnetic modulation converter with an excitation generator and an integrator connected to it, which is connected to a threshold unit, and a compensation unit, in order to improve the reliability of the device by reducing the error compensation of external magnets. fields, the compensation block is made in the form of a binary counter, a digital-to-analog decoder, the first and second circuits And and the compensation bus, and the output is digital-analog The second amplifier is connected to a magnetically-modulated converter, and the input is connected to the output of a binary counter, the input of the zero setting is connected to the compensation bus, and the counting input is connected to the output of the first circuit And, the inputs of which are connected to the output of the threshold unit, the excitation generator and the compensation bus f The first input of the second AND circuit, the second input of the latter is connected to the output of the threshold block, and the output is the output of the device. five

Description

Fffe.f 110 The invention relates to the field of depth measurement in the field geophysical service of boreholes. The device for reading magnetic tags preliminarily applied to a logging cable, including an electronic relay and a magnetic probe that provides reading tags at low cable speeds and a device, is a weak reading of weak tags during long-term operation of the cable with marks in the wells. It is also known a device containing a magnetic probe and a puncher, while to increase the noise immunity between the magnetic probe and the puncher, a threshold device and a logic unit are enabled to ensure the triggering of the tap of a specific shape C2. This device provides a stable reading of the set marks among the false marks on the cable, due to poor erasure of old marks or contact of the cable with magnetized objects, but there is no reliable reading of weak marks in the surrounding conditions. magnetic fields present at the installation point of the device in the depth reference plane of the well. The closest technical solution to the proposed one is a tag sensor containing a magnetically modulated transducer, an integrator, a threshold unit and a compensation circuit for the surrounding magnetic field, including a source of adjustable DC magnitude and direction, and an output winding of the magnetically modulated transducer. The current supplied to the output winding of the converter creates in its core a magnetic flux directed opposite to the flow caused by the surrounding field and compensates for it. Compensation allows increasing the stability of reading the tags in the presence of surrounding magnetic fields of the SPZ. However, in this sensor, compensation is performed manually, which reduces the stability of reading weak marks due to compensation errors. The purpose of the invention is to increase the reliability of the device due to the reduction of E2 and the error of compensation of external magnetic fields. The goal is achieved by the fact that, in a device for reading memory labels, when measuring the depth of a well, which contains a magnetic modulating transducer with an excitation generator and an integrator connected to the threshold unit, and the compensation unit, the compensation unit is designed as a binary counter, digital to analog. first and second circuits And and compensation bus, and the output of the digital-to-analog converter. connected to a magnetically modulated converter, and an input to an output of a binary counter, the zero input of which is connected to the compensation bus, and the counting input to the output of the first circuit AND whose inputs are connected to the output of the threshold unit, the excitation generator and the compensation bus whose foot is connected the input of the second circuit is And, the second input of the latter is connected to the output of the threshold unit, and the output is the output of the device. FIG. 1 shows a block diagram of the proposed device; in fig. 2- stress and magnetic flux diagrams. The sensitive element of the device is a magnetically modulated converter 1, excited by a pulse current from generator 2. The output of the magnetic modulating converter 1 is alternately connected via an integrator 3 to a threshold unit 4, which is connected to the 6 mark bus through the second circuit 5. With a direct current, the output winding of the magnetic modulation converter 1 is connected to the output of a digital-to-analog converter 7 connected to the inverse outputs of a binary counter 8 having a counting input and a zero setting input. The counting input of the counter 8 through the first circuit And 9 is connected with the output of the generator 2, the threshold unit and the compensation bus 10, to which the meter installation input is also connected. ka to zero. By the output line 6 and the compensation line O, the device is connected to a logging station. A manual installation button 11 is connected to the compensation bus 10. The operation of the device depends on the total intensity of the surrounding magnetic field and the label field in the vicinity of the magnetic modulating transducer. When reading tags when the surrounding field is insignificant (Fig. 2a), the magneto-modulation converter 1 outputs a sequence of pulses (Fig. 2g), whose amplitude is proportional to the magnitude of the non-magnetic flux generated) in its core by the north pole of the label (Fig . 2 c). This signal is integrated to suppress interference from the integrator 3 and in the form of a voltage of constant current (Fig. 2 (supplied to the threshold unit 4. When the input voltage exceeds the actuation level (Fig. 2), the threshold unit forms a positive voltage drop (Fig 2 6), which is fed to the tag output bus 6 through the signal quality circuit 58 and the label (Fig. 2k. Reading tags under conditions of surrounding fields of high intensity (Fig. 3a and a) occurs in a similar way after compensating for the surrounding field Compensation is made when serving with Compensation (Fig. 3 kS) at the input 10 or when the button 11 is pressed, when there is no mark in the vicinity of the magnetic modulation converter. At the Compensation signal, the counter 8 is set to zero, the AND 9 circuit is blocked And the digital-to-analog converter is blocked 7 begins to issue a current into the output winding of the magnetically modulated converter (Fig. 3it and 4 U.), creating in its core a compensating magnetic flux. This causes a change in the magnitude and direction of the total magnetic flux in the core (Fig. 3.6 and k) and the appearance of the output signal of the magnetic modulation converter (Fig. 32, and 42,), which, after integration (Fig. 36 and kd) and forming the poroBbiM device (Fig. 3 and 4) allows the passage of pulses from the generator 2 through the circuit And 9 on. the counter input of counter 8. The counter starts counting in the forward direction, as a result of which the output current of the digital-to-analog converter starts to change from the maximum positive to maximum negative value, which causes a decrease in the total flux and output signal of the innitho-modulation converter 1. When the signal drops below the release level of the threshold device, the counter in meter 8 and the change in the output current of the converter 7 is stopped. In this case, the magnetic flux in the core of the magnetic modulation converter 1 generated by the current of the digital-analog converter 7 is equal to and opposite to the direction of the flow created by the surrounding field and compensates for it at the release level of the threshold block with an accuracy determined by the discreteness of the digital-analog converter 7. When the Compensation signal is removed, the device provides for reading tags that exceed the spacing intensity, and trigger and release levels of the threshold unit. To eliminate the effects of changes in the surrounding field, compensation is made immediately before reading the tags. Thus, the compensation of the surrounding field in the device is performed with great accuracy immediately before reading the tags, which makes it possible to choose the level of release of the threshold block close to the trigger level, and thereby significantly increase the stability of reading the weak marks. This makes it possible to reduce the frequency of marking of the logging cable and to improve the accuracy of reference of the field geophysical information to the depths in the wells. When using an eight-digit D / A converter in the device, the surrounding field with a strength of up to 16.00 A / m can be compensated with an accuracy of i 6.25 A / m. This allows you to select the difference between the trigger levels and the release of the paBHovi threshold device 12 A / m and ensure a stable reading of tags with a field strength of 18 A / m, instead of 80 A / m, which occurs when using MejoK sensors with manual compensation. Since usually the tag field strength, immediately after marking the cable 800 A / m, drops to 80 A / m after servicing 10-12 wells and to a level of 20 A / m after 20-25 wells, the increase in the stability of the tags the expense of more accurate compensation of the surrounding field in the proposed device) makes it possible to reduce the frequency of marking of the cable by about S101 by 2 times. Together with a decrease in the number of repeated measurements in wells caused by inaccuracies in depth data binding due to poor readings of tags, this gives an annual economic effect when servicing wells drilling for oil and gas 5 9 "in size of about 200 thousand rubles. in year. Automatic compensation in the proposed device simplifies. logging geophysical information and allows its use in software-controlled logging stations.

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Claims (1)

DEVICE FOR READING MAGNETIC METHODS WHEN MEASURING A WELL DEPTH, comprising a magnetomodulating transducer with an excitation generator and an integrator connected to it, which is connected to a threshold unit, and a compensation unit, characterized in that, in order to increase the reliability of the device by reducing the error of compensation of external magnetic fields, the compensation unit is made in the form of a binary counter, a digital-to-analog converter, the first and second AND circuits, and a compensation bus, the output of the digital-to-analog pre the developer is connected to the magnetomodulating transducer, and the input is to the output of the binary counter, the zero-setting input of which is connected to the compensation bus, and the counting input to the output of the first AND circuit, the inputs of which are connected to the output of the threshold block, the excitation generator, and the compensation bus, to which the first input of the second AND circuit is connected, the second input of the last is connected to the output of the threshold block, and the output is the output of the device. Fie. f 6L65G0T ^{, and,} 7T§