SU868675A1 - Meter of time interval for acoustic well-logging apparatus - Google Patents

Description

(54) INTERVAL TIME METER

FOR ACOUSTIC EQUIPMENT

I

The invention relates to computing and measuring technology, is intended to measure the average difference in duration of two random alternating time intervals and, in particular, can be used in acoustic logging equipment for measuring the interval time of propagation of elastic vibrations in the medium under study at a given distance.

A device is known consisting of two time interval meters and a subtraction unit, from which output a voltage is applied to the recorder proportional to the difference in the duration of time intervals 1.

The disadvantage of the device is the dependence of the output voltage on the pulse frequency, the difficulty of ensuring the identity of the characteristics of the two time interval meters, and the presence of 1x pulsations of the output parameter caused by non-simultaneous charging and discharge current pulses to the storage element.

It is also known a device containing an autonomous DC generator, three WELLS

electronic key, discharge metering capacitor, storage capacitor and voltage follower 2.

The drawback of the device is the presence of instrumental pulsations caused by non-simultaneous arrival of time intervals at the device input.

The closest to the proposed technical is the device, which consists of a DC generator, one pole

10 of which is connected to the middle contact of the first key, the second pole to the middle contact of the second key, the first contacts of the first and second keys are grounded, and the second are connected to the diode anode and to the ungrounded

15 by an intermediate capacitor plate, the cathode of the diode is connected to the input of a DC amplifier, with one plate of a storage capacitor, with one plate of a discharge metering capacitor and with one contact of a third switch, the second contact of which is connected to the second plate of a storage capacitor, with an amplifier output direct current and output device. The control input of the first key is supplied with pulses of TI duration, and the pulses of TJ 3 are supplied to the control input of the second. The disadvantage of the device is that the charging current pulse arrives at the storage capacitor for a time interval and a proportional difference of the pulses of the input pulses, and the discharge is carried out with the help of a metering capacitor and a switch instantly. Since the charge and discharge current pulses do not enter the memory capacitor simultaneously and have a different shape, the output parameter of the current device contains instrumental pulsations that reduce the measurement accuracy. The purpose of the invention is to improve the measurement accuracy. The goal is achieved by the fact that in the interval time meter for acoustic well logging equipment, a DC generator is contained, one pole of which is connected to the grounded contact of the first key, and the second pole is connected to the grounded contact of the second key, second contact of the first key. And second contact the second key is connected to the ungrounded lining of the intermediate capacitor, the control input of the first key is connected to the first input of the device, the control input of the second key is connected to the second the input of the device, the third key, the first contact of which is connected to the ungrounded plate of the intermediate capacitor, and the second contact is connected to the first plate of the storage capacitor and the first input of the DC amplifier, the second input of which is, and the output is connected to the second plate of the storage capacitor and is the output devices, two one-shot and fourth A1yuch are additionally introduced, the input of the first one-shot is connected to the second input of the device, the output of the first one-shot is connected to the control the input of the third key and the input of the second one-shot, the output of which is connected to the control input of the fourth key, the first contact of the fourth key is connected to the ungrounded lining of the intermediate capacitor, the second combination of the fourth key is connected to the output of the DC amplifier. The drawing shows the functional scheme of the proposed device. The meter consists of the first controlled switch 1, the autonomous generator 2 of direct current, the second controlled switch 3, the intermediate 504 capacitor 4, single vibrators 5 and 6, the third controlled switch 7, the fourth controlled switch 8, the storage capacitor 9 and the displacer 10 direct current. The control input of the key 1 is connected to the input I, and the control input of the key 3 is connected to the input 12 and to the input of the one-vibrator 5. The first contacts of the keys 1 and 3 are grounded, the second is connected to the ungrounded lining of the intermediate capacitor 4 and to the first contacts of the keys 7 and 8 One pole of the autonomous generator 2 of direct current is connected to the middle contact of the control key 1, and the second pole - to the middle contact of the control key 3. The output of the one-vibrator 5 is connected to the input of the one-vibrator bis input of the control key 7. The output of the one-vibrator 6 is connected to the input of control key 8. The second contact of the key 7 is connected to the input of the 10 DC amplifier and to one plate of the storage capacitor 9, the other plate of which is connected to the output of the DC 10 amplifier, to the output 13 and to the second contact of the key 8. To the input 11, the device is pulsed with TI, and input 12 is TJ. The output 13 is the output of the device. The device works as follows. When a pulse with duration t I arrives at the input I, key 1 connects current generator 2 to capacitor 4 and the latter receives charge qi OoTi, where Zo is the current value of generator 2. When pulse impulse t duration 2 arrives at input 12, generator 2 reports to capacitor 4 via key 3 charge q2 -iloTj. On the leading edge of a pulse of duration g 2, a single vibrator 6 is triggered, the capacitor 4 is discharged to the input of the DC amplifier 10, and the charge on the storage capacitor 9 is changed by an amount equal to the value of the charge on the capacitor 4. At the output of the amplifier, voltage and. After the end of the pulse of the one-shot 5, the one-shot b is started and through the switch 8 it charges the capacitor 4 to the voltage Ug; after which, with the arrival of a pulse of duration TI, capacitor 4 receives a charge equal to qt, etc., i.e. the cycle is repeated (fs. Oshta by the start of cyclization of capacitor 4 to the voltage Ug, and by the end of the discharge of the capacitor to the input of the amplifier 10, it is possible to record the total charge on the capacitor 4 in one cycle. Aq q, "qz -CUe, where C is the capacitance value of capacitor 4. At the end of each cycle, the magnitude of this charge at the storage capacitor 9 changes. After the completion of the transient process, the charge value at the storage capacitor 9 is kept constant, i.e. the total charge at capacitor 4 for one cycle will be zero aq o

Consequently,

Qi + qj - CUe 0; loTi - loTz - CUg 0 From where it is possible to determine the pattern on

the output of the device 6 (g. I) Co. (t, - TI) Code

and about

where ko scale factor.

Thus, the output voltage is linearly dependent on the measured difference in the duration of the two alternating pulses.

Since the operation of subtracting the durations of time intervals is not carried out on the memory capacitor, the device measures the interval time without instrumental pulsations of the output parameter, and this results in an increase in the measurement accuracy.

Claims (3)

1. Ivakin B. N., Karus E. V., Kuznetsov O. L. Acoustic well research method. M., 25 Nedra, 1978, p. 152-154. 2. Converters measuring measuring systems. Kiev, Naukszha Dumka, 1978, p. 32. 3. Medved Ya.V., Fedoriv R. F. Enhance, 30 accuracy of measurement of integral time in acoustic logging of wells. Sat Geophysical instrumentation, l. 64, M., Nedra, 1978, with. 120-123 (prototype).