SU768948A1 - Apparatus for digital recording of logging results - Google Patents

Description

one

The invention relates to geophysical equipment for digitally recording results of geophysical field studies in wells.

There are a number of devices for digitally recording geophysical research data in wells based on the conversion of analog signals into a binary or binary-decimal code with subsequent recording of these numbers on the carrier (mag. Tape, punched tape, etc.).

A multichannel logging data recorder is known, which contains an information sensor, an amplification unit and a channel selector in each channel, as well as a digital analog-code converter, a control device, a graphic recording device, a digital magnetic storage device, and a sync pulse sensor 1.

The disadvantage of this device is that it is adapted to register only analog signals.

In this case, a double conversion of the pulse-analog-to-digit signal occurs and the measurement error increases. In addition, the instability of the ascent rate of the downhole sensors is not taken into account, which leads to additional errors when recording radioactive logging signals and reduces the accuracy of the subsequent interpretation of these data.

It is also known a device for registration of field geophysical research 5 of a scientific research institute containing preamplifiers connected via electronic switches and a channel switch with an analog-to-code converter, a magnetic recorder and a depth encoder, and between

10 analog-to-code converter and a magnetic digital recorder include a memory cube, the control circuits of which are connected to the control output of the analog-code converter and a program block whose output is connected to the output of the channel switch, whose input is via the start switch and the switch. to the output of the master oscillator, and the launch key input is connected to

20 by a magnetic digital recorder directly and through a depth encoder 2. This device allows to coordinate information from sensors that are displaced in depth and link information to depth from descent and ascent.

The closest is a device for multiplex digital recording of logging results, containing a channel switch (multiplexer).

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the output of which is connected to the accumulator and reproducing device through serially connected converter analog-code, arithmetic and buffer storage units and sorter, and control unit whose output is connected to the channel switch, analog-code converter, arithmetic and buffer storage units , sorter, accumulator, playback unit and tester, the output of which is connected to the input of the channel switch 3.

When registering signals using this device, there is another kind of error that is not taken into account in these devices.

All reasoning about the nature of the error of the radioactive logging signal is carried out under the condition that the Y-logging speed is constant. In fact, when lifting with the help of an automobile winch cable, on which the probe is fixed, three types of speed fluctuations are observed.

First, the diameter of the drum on which the cable is wound varies, which causes a smooth change in the lifting speed from the beginning to the end of the lift. This change is significant and it is attempted to be compensated for by manually changing (by the operator) the engine revs of the lift; secondly, the uneven movement due to the different force of the probe friction against the borehole wall; thirdly, the change in speed in critical situations, for example, when a cable coil creeps into a coil and then slips off.

Oscillations in the second and third cases are random and cannot be taken into account in advance. Real speed fluctuations violate the statistics of readings (especially at low signal levels) and the reception of errors in signal processing and the issuance of a geological conclusion.

The aim of the invention is to improve the accuracy of processing signaling of logistic types of logging (for example, radioactive).

This goal is achieved by the fact that in a known device for digital recording of measurement results, containing a channel switch, the output of which is connected through an analog-code converter, a buffer block and a format converter to the drive input, and a control block whose output is connected to the common bus COM1 (bytator of channels, analog-code converter, buffer block, format transformer, accumulator and bycopier playback, the control unit is additionally connected to the buffer block via a coding block Depth intervals and a signal coding block connected to the input of statistical pulse signals. This allows you to simultaneously record the number of pulses L, reflecting the parameter intensity on the sampling interval by depth D, and / is the time interval of interval D. At

5 this dependence, V / (I) expresses the change in the desired parameter along the wellbore, and the change in / (H) - the change in the logging speed. The drawing shows the scheme of the proposed Q device.

The device has four inputs X, Y, Z, V, and X is the input of analog signals, Y is the input of statistical pulse signals, Z, Y are inputs of depth signals.

15 To switch X, a switch of channels 1 is connected, the output of which is connected to the input of accumulator 5 through the converter analog-code 2, buffer unit 3 and format converter (sorter) 4, output

0 which is connected to the input of the playback unit 6 via a format converter

4 and the buffer unit 3 to which the calculator 7 is connected.

A control unit 8 is connected to the Z and Y inputs, one of the outputs of which is connected to block 3 via the depth interval coding block 9 and the signal coding block 10, and the other via the common bus -. with channel switch 1, analog-code 2 converter, buffer block 3, format 4 converter, storage

5 and a playback unit 6. A signal encoding unit 10 is connected to an input of statistical impulse signals (Y).

g The device has two modes of operation - “Record and“ Play. When recording, the signals received at the inputs X or Y are recorded on a magnetic tape. During playback, the recorded information is read from a magnetic tape for monitoring or further processing.

In recording mode, non-statistical signals (for example, electrical signals

5 logs) are fed to the inputs X of the switch of channels 1, where they are amplified and alternately fed to converter 2. Conversion signals (numbers) are fed to block 3, where they are complemented

The Q overhead information (and, for example, depth information) coming through the common bus from the control unit 8. During the stay in the buffer block, 3 numbers look like a 16-bit binary code, and 11 bits carry information about the ammeter size Five bits carry the service information necessary for further processing.

Q From the buffer unit 3, after accumulating information from all the channels of the number, through the format 4 converter, in which each number is rolled up into 8-bit combinations (bytes),

for registration into accumulator 5. Simultaneously from block 3, numbers are transferred to reproducing unit 6 and calculator 7. To represent digital information in analog form, for example, for visual control using an electronic oscilloscope or photo oscilloscope of a logging station, the reproducing unit contains code-voltage schemes).

As a calculator, a specialized on-board calculator can be used, or the ECM is small. The transmitter 7 calculates the actual parameters of the well (for example, porosity) using for this purpose numerical information from the analog-code converter.

2, or the information recorded in the drive 5.

Statistical signals (for example, radioactive logging signals) through inputs Y are fed to the signal coding unit 10, which converts the incoming pulse sequence into a binary code as a function of depth. Block 10 may contain, for example, binary counters, the signals to which are received through keys gated by the depth interval A i, which is set by the control unit 8. Block 8 forms depth intervals D i using depth information (depth marks and depth quanta) which comes from the corresponding devices of the standard logging station to the inputs Z and U.. Thus, the coding unit generates some numbers jVj reflecting the amplitude of the statistical signal in a given channel, averaged over the depth interval Ai (for example, over the 0.1 m interval). These numbers, in the form of an 11-bit binary code, enter the block

3, where supplemented with service information. At the same time, the depth interval coding unit 9, containing a quartz clock (generator) and scaling circuits, measures the time of existence of the interval A i. The resulting result goes to block 3 to supplement the number of the parameter Ni and further, similarly to non-statistical signals, to the calculator 7, the playback unit 6 and through the format 4 converter to the drive 5.

Regardless of the type of recorded signal in the playback mode, each information zone recorded, for example, on a magnetic tape and carrying information about all signals from inputs X or Y,

related to the same depth interval Ai is read from accumulator 5 to format converter 4 and from it to calculator 7 and playback unit 6. Communication of buffer unit 3 with calculator 7, playback unit 6, format converter 4 and accumulator 5 allow with the minimum hardware volume to carry out all modes (recording,

reproduction, control, calculation, etc.), without switching blocks and not entering new devices.

The calculation of the logging results can be done in the recording process, but

“Reproduction” is preferred, since in this case all information about the well is recorded on the media. The change in the number of Ni in the wellbore gives the desired parameter, and the change in the lifetime of the interval, the depth ti in the wellbore reflects the change in the error of digital recording from the speed of the sensors. Making a calculation, the computer gets the opportunity

monitor the error condition of the registered information, input the result correction if necessary, which significantly improves the processing accuracy.

Claims (3)

1. USSR Author's Certificate No. 239893, cl. E 21B 47/00, 1966. 2. USSR author's certificate number 441542, cl. G 01V 3/18, 1971. 3. Patent of the USSR No. 503544, cl. E 21B 47/00, 1971 (prototype).