SU1068859A1 - Device for registering acoustic parameters in well-logging - Google Patents

Abstract

A DEVICE FOR REGISTRATION OF ACOUSTIC PARAMETERS DURING CAROTATION OF WELLS, s. Containing a serially connected one-shot and key, as well as a memory circuit, a circuit, a formation, a comparison device, a coincidence circuit, a lock generator and a current generator, characterized in that, with increasing accuracy by reducing the error the registered parkmetrov from temperature instability, the first input of the comparison device is connected to the output of the key, the input of which is connected to the first input of the coincidence circuit and to the input of the circuits the second input of the comparing device is connected to the output of the memory memory chip, the first input of which is connected to the output of the comparing device, which is connected to the input of the matching circuit, and the second input of the memory circuit is connected to the output of the matching circuit, and the third input of the matching circuit is connected to the output a lock generator, and both outputs cx & ta ta matching are connected to current generators. rCD

Description

The invention relates to well logging and can be used in the development of acoustic well equipment. A device is known for recording the logarithm of amplitude ratios for acoustic logging (AK) of wells, in which the detected signals are sent to two diode logarithmic transducers built on the principle of piecewise linear approximation. The resulting voltages are fed to a subtraction circuit whose output current is proportional to the logarithm of the amplitude ratio l3. The drawback of the device is that the conversion of the amplitude to the logarithmic voltage is carried out in steps, in each of which the proportionality with the logarithmic transformation law is violated. There is a known method for recording time parameters in AK, which consists in measuring time by separating the response of the threshold device from the signal exceeding a certain level of C23. As the amplitude of this signal changes depending on the well conditions, the threshold response time device, which is a disadvantage of the method and device. The closest to the invention is a log of an amplitude ratio rhyme log containing two single vibrators (or a symmetric multivibrator), two schemes of averaging the gain values of signals from the near and far emitters of the acoustic probe, a key, and a shaping circuit (ks 1parator} which forms the voltage variable in logarithmic exponential, open transistor, compensating for temperature influence, comparing device, coincidence circuit, multivibrator (blocking generator) and g current ramp. A pre-detected signal arrives at the input of the device. This voltage goes to two identical jamming circuits. The voltage to the memory circuits arrives at certain time intervals, which are formed by two one-vibrator and 1, respectively. the key to the voltage shaping circuit with the logarithmic .cna house of the falling front, which in turn goes to the comparison device, with the second circuit using an open transistor, which The voltage is affected by temperature, the voltage is applied to the second input of the comparator. The differential voltage is amplified by a comparison device, and the generated rectangular pulses are fed to a coincidence circuit, which passes rectangular pulses with a duration proportional to the logarithm of the amplitude ratio, to the input of the current generator. The control of the coincidence circuit and the key is carried out by a single vibrator, which forms rectangular pulses of a certain duration C3. The disadvantage of the known scheme is that the error due to temperature influence is not fully compensated, since the compensation element (open transistor) is intended to compensate for thermal stability only of the comparator (formation circuit). Compensation for the instability of selectors and memory circuits, despite their nominal symmetry, cannot be complete because of the actual differences in thermal stability of the semiconductor elements, due to the spread of their parameters, such instability in The temperature range from 10 to 45 can reach 70 mV, which is comparable with the signal size in the lower dynamic range region (for K140 type IC chips, 1B signals are of the order of BO mV). Stability can be improved only by special selection of elements,. . . The total error increases due to the instability of the supply voltage and can be a significant amount,. The purpose of the invention is to increase accuracy by reducing the error of recorded parameters from temperature instability (E). The goal is achieved in that the device for recording acoustic parameters containing serially connected one-shot and key, as well as the memory circuit, the formation circuit, the equalization device, the coincidence circuit, the generator interlock and the current generator, the first time of the comparison device is connected to the output of the key, the input of which is connected to the first input of the matching circuit and to the input the house, the forming circuit, the second input of the comparing device is connected to the output of the injection circuit, the first input of which is connected to the output of the comparing device, which is connected to the input of the matching circuit, and the second input of the 4PC generation circuit (connected to the output of the forming circuit, The third input of the coincidence circuit is connected to the output of the blocking generator, and both outputs of the coincidence circuit are connected to the current generators Figure 1 shows the block diagram of the device for recording aerial parameters during well logging; Fig. 2 shows diagrams of the DIRECTORY that show his work. The device (FIG. 1) contains one vibrator 1, memory circuit 2, key 3, formation circuit 4, comparing device 5, circuit 6, locking generator 7, current generators 8 and 9, and photo recorder 10. the shape of the strobe-pulse 11, the packet of the original wave pulses 12, the pulse 13, converted into amplitude, the pulse 14, converted into a duration, and (differential pulse 15. The device works as follows. On the non-inverted input, a packet arrives on device 5; impulses 12 allocated key 3. Controlled Key operation is carried out with a rotor pulse of 11. 11. It is removed from the one-vibrator 1. The key's operation is based on shunting the variable component voltage throughout the variable interval, except for the time interval of the impact of the strobe pulse 11. At this time, the key 3 is closed and the packet of wave pulses 12 is fed to the first input of the comparing device 5. The packet of wave pulses 12 is amplified by the comparing device 5 and is fed to the input of the circuit 2 for storing the maximum of the phases of the selected pulse packet 12. Control of the PSM circuit 2 A pulse 13 is removed from the formation circuit 4, the memory circuit 2 maintains an amplitude with a peak value of pulse 13 for a time equal to the duration of the strobe pulse 11. At the end of the strobe pulse 11 s output of the jamming circuit 2, the pulse 13 enters the second The input is compared to device 5. Since the comparison device 5, after comparing the pulse packet 12 with the pulse 13, results in additional amplification, very small differences are trapped, forming a difference signal, which is an indication of the comparison error And stabilization of the operating mode of the device. At the end of the action of the strobe pulse 11, the signal at the non-inverting first input of the comparator device 5 is absent, and at the second the input will continue to be impacted by the pulse 13, which locks the amplifier compared to the first device 5. As a result, pulse 13 will be amplified to limit and a rectangular pulse 14 will be formed at the output of the comparing device 5. Since the formation of the logarithmic exponent begins at the end of the gate-pulse 11, the pulse duration 11 is subtracted from the pulse 14 in the matching circuit 6 formed as the difference of pulses 14 and 11 from the first probe from the coincidence circuit is fed to the input of the current generator 8 (from the second probe, the signal, respectively, is fed to the input current generator 9) f control of the coincidence circuit 6 uschestvl a lock generator 7. Between the output points of the current generators 9 and 8, the logging station 10 of the logging station is turned on, the deviation of the flare of the galvanometer corresponds to the hcwy voltage to the voltage of the current generators, i.e. proportional to the logarithm of the ratio of the input signals from the first and second probes of the downhole tool. The device can also be used to record the amplitudes of acoustic signals. In this case, the storage circuit 2, in conjunction with the formation circuit 4, is a linearly falling voltage. As a result, a rectangular pulse with a duration proportional to the amplitude of the input signal is formed at the output of the comparative device 5, and DC voltage is removed from each current generator proportional to the amplitude of the acoustic signal from the corresponding probe of the downhole tool. Connecting the memory circuit 2 to the output of the comparator device 5 allows storing two information signals in one circuit and, therefore, using one channel for processing signals received from two probes of the downhole tool. In addition, comparing the variable to 1 signal of the memory circuit 2 with the signal from the preamplifier with the power of one channel makes it possible to avoid the thermal instability error arising during the operation of two full channels. Thus, the amplitude-to-duration conversion is proportional to the single-num- ply - is carried out in one AZ common channel, which excludes the appearance of additional errors b of the various effects of temperature. The device improves the accuracy of determining the position of the vertices of the Singsh and, therefore, can be used to record the interval time. As can be seen from FIG. 2d pulse t4, the first negative edge of the rectangular pulse corresponds to the position of the apex of one of the first phases of the received signal and, consequently, this front does not depend on matching the threshold device of the time measurement channel by level. In known devices, the time measurement error can reach a quarter of a period. In addition, the ability to determine the position of the vertices of the signals with high accuracy allows the device to be used in the AKIUS and other equipment to form CRT illumination pulses at the maxima of the amplitudes of the signals. In this case, a gate-pulse in the device must be formed for each

phase of the signal, for example, Schmidt trigger.

In addition, a certain structure of the layout of the circuit elements allows it to be used to register any of the main acoustic signals.

L parameters A ;, tfj, forming no pulses, corresponding to the position of the vertex of each of the phases of the incoming signal, and thereby unify the measuring devices of the acoustic logging equipment.

L /

F1 / g.2

Claims (1)

DEVICE FOR REGISTRATION OF ACOUSTIC PARAMETERS DURING BOREHOLE LOGGING, containing a serially connected one-shot and a key, as well as a memory circuit, a formation circuit, a comparing device, a matching circuit, a block generator * and current generators, characterized in that, for the purpose of increasing accuracy by To reduce the error of the recorded parameters from temperature instability, the first input of the comparison device is connected to the output of the key, the input of which is connected to the first input of the matching circuit and to the input of the circuit ormirova- _with Nia, the second input of comparator Device for $ roystva connected to the output of memory circuit having a first input connected to the output of the comparator which is connected to the input matching circuit and the second input memory circuits connected to the output generation circuit, the third input circuit matches are connected to the output of the lock generator, and both outputs of the match circuit are connected to current generators. 988 901 0S Fig!