SU1298361A1 - Method of investigating wells - Google Patents

Abstract

The invention relates to geophysical surveys of oil and gas wells using cable-launched instruments. The goal is to increase the accuracy and reliability of measuring geophysical parameters. A downhole tool (SP), connected through a cable and a guide roller to a ground panel, is lowered into the well. During the movement of the joint venture, the geophysical parameters and parameters characterizing the movement of the joint venture are measured and transmitted along the cable to the surface for recording. At the same time, the processes of moving the information transmission and recording information are carried out synchronously. In order to match the synchronization frequency F, with the process of movement, it is varied depending on the speed V of the movement of the SP by the formula F y-P V 2F-Ch, where y is the measurement error; h is the quantization step; F is the width of the hard spectrum of the measured signal; Р - power consumed from the source of information; C - energy threshold of sensitivity. 1il i SL e

Description

The invention relates to geophysics, in particular to the study of oil and gas wells with the help of instruments running on a cable.

The aim of the invention is to increase the accuracy and reliability of measurements of geophysical parameters.

The drawing shows a schematic diagram of the implementation of the method.

An outcome from the Kotelnikov theorem and based on the results of P. Novitsky’s research, one can get the expression

N. g -, (1)

where w | - number of channels (measurements); measurement error; energy threshold of sensitivity;

the limit value of the frequency of the spectrum of the signal; consumed from; source of information power. This swelling is essentially; 5)

If

with

F - P device. With this agreement, the measurement error will not depend on the speed of the instrument. From expression (4) we get y2 - Ic2FCh

yy pv

At present, in well testing, the synchronization frequency is usually constant, i.e.

fO Fj const5 and the speed changes, i.e. . Therefore, the error varies inversely with the speed change. If the clock frequency is a function of speed

15 movements of the device, i.e. is adjusted in accordance with expression (5), then the measurement accuracy is improved by aligning the movement processes with the measurement and data transmission processes and ensuring the independence of the speed of movement.

It follows from the above that expression (4) is the analytical expression according to which

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with the mathematical model of a multichannel, control (of the measurement process (transformation) of the synchronization frequency by the measurement and data transfer processes during logging) must be carried out. Such control ensures the adaptation of measurement modes 30 and data transfer to the process of the instrument movement.

nor) with a temporary seal channels.

The logging process is a combination of at least two processes — a measurement process and a motion process. Therefore, it is possible to obtain a formula similar to expression (1) and determining the number of measurement channels depending on the speed of movement of the instrument.

TG V,

(2)

and - IL - ,, g)

Mr. V

where F is the synchronization frequency of the switches of the downhole tool and the ground equipment; - quantization step length; V is the speed of movement of the device. Obviously, the coordination of the considered processes is possible under the condition

40

 P

shown is an increase in measurement accuracy.

The implementation of the method can be carried out using a logging station equipped with a computerized logging laboratory LK-01. This laboratory is equipped with a power supply unit for downhole equipment, which is controlled by microcomputers. The laboratory works with complex borehole devices of type K 1A-723. These devices are equipped with elements that control the speed of movement of the device. The signal from the downhole tool, which characterizes the movement of the device, enters the microcomputer, from which a control signal is sent to the power supply unit to change the frequency of the downhole tool power supply. The frequency of this power supply is the synchronization frequency of the switches (borehole and ground) of multi-channel measuring and transmitting equipment. In these laboratories, data recording is carried out with the help of paper carrier, the drive control of which is very simply carried out by voltage

45

N,

N,

. (3)

From here it is not difficult to get an expression

hg, 11 s. 2FCh

(four)

It is obvious that the synchronization frequency, consistent with the measurement and transmission processes, is linearly dependent on the speed of movement. At the same time, it shows how it is necessary to coordinate the synchronization frequency with the movement process.

;five)

device. With this agreement, the measurement error will not depend on the speed of the instrument. From expression (4) we get y2 - Ic2FCh

yy pv

At present, in well testing, the synchronization frequency is usually constant, i.e.

Fj const5 and the speed varies, i.e. . Therefore, the error varies inversely with the speed change. If the clock frequency is a function of speed

device movements, i.e. is adjusted in accordance with expression (5), then the measurement accuracy is improved by aligning the movement processes with the measurement and data transmission processes and ensuring the independence of the speed of movement.

It follows from the above that expression (4) is the analytical expression according to which

the synchronization frequency should be controlled (changed) by the measurement and data transfer processes in logging. Such control provides adaptation of measurement and data transfer modes to the process of movement of the instrument. The result of this is how

shown is an increase in measurement accuracy.

The implementation of the method can be carried out using a logging station equipped with a computerized logging laboratory LK-01. This laboratory is equipped with a power supply unit for downhole equipment, which is controlled by microcomputers. The laboratory works with complex borehole devices of type K 1A-723. These devices are equipped with elements that control the speed of movement of the device. The signal from the downhole tool, which characterizes the movement of the device, enters the microcomputer, from which a control signal is sent to the power supply unit to change the frequency of the downhole tool power supply. The frequency of this power supply is the synchronization frequency of the switches (borehole and ground) of multi-channel measuring and transmitting equipment. In these laboratories, data recording is carried out with the help of paper carrier, the drive control of which is very simply carried out by voltage

variable frequency coming from the specified power supply

The implementation of the method, i.e., of the synchronization frequency control mode, can be demonstrated by the example of a system whose functional diagram is shown in the drawing. The diagram is a functional diagram of the integrated device K 1A-723 developed on the basis of the downhole tool system (ASKP).

The drawing shows a downhole tool 1 comprising a filter 2 for separating a 400 Hz supply voltage from information pulses generated by a voltage converter 3 — the duration of a time interval or a pulse width modulator (GSM), to which information 4 is received from switch 5 Power supply of electronic elements and assemblies of the wellbore device is carried out from the secondary source 6. At the same time, among these dates, 25 is voltage, proportional to

The tension sensor (force), which controls the tension between the devices and the lower end of the cable, is also located. A strain gauge pressure transmitter D-100 is used as a tension sensor.

The downhole tool is connected via cable and guide roller 7 to ground panel 8, which includes frequency separation filter 9 (400 Hz (power supply voltage of downhole tool), driver 10 synchronization pulses, channel number 11 counter;), decoders (multiplexers) 12 and 13, the shaper 14 of the duration of the time (information) interval based on the trigger, the power supply source 15 of the well equipment UG-1, serially produced, the time interval-voltage converter 16, and the actuator (micromotor) 17. Moreover, to implement the method, the newly introduced elements in the functional diagram of the integrated device K 1A-723 and the ground panel, respectively, were introduced a tension sensor, a decoder (multiplexer) 12, a converter 16 and an actuator 17.

The implementation of the method is carried out during the operation of the entire system as follows. When changing the speed of movement of the device 1

This change in the form of voltage, proportional to the acceleration of the device, from the tension sensor through the switch 4 is fed to PWM 3. Next, weft into

the form of a sequence of durations of time intervals through the filters 2 and 9 information enters the ground part. The number of time intervals depends on the number of sensors in

the instrument, Dp, the selection of each cycle of the survey of sensors from the downhole tool also receives marker pulses, with the help of which the selection of channels corresponding to

specific sensors. This procedure is carried out using a synchronization pulse generator 10, a counter 8, multiplexers 12, 13, and a trigger generator 14, Geophysical information from the decoder-multiplexer 13 is fed to the registration, and the cable tension information from the decoder 12 is fed to 16 time transducer - voltage. Magnitude30

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The device is converted from the converter 16 to the electric motor 17. Since the electric motor is an integrating element, its rotational speed is proportional to the speed of movement of the devices. Rotating the potentiometer, the motor thereby changes the frequency of the supply voltage of the UG-1 in accordance with the j formulas given.

Claims (1)

Invention Formula The method of investigating wells, including measurements of geophysical parameters during the movement of a downhole tool and parameters characterizing the movement of the device, transferring the measured information through the cable to the surface and its registration, as well as synchronizing the process of recording information with the process of moving the downhole tool, differs from in order to increase the accuracy and reliability of measuring geophysical parameters, they change the frequency of synchronization of the processes of measuring parameters, transmitting and recording information depending The velocities of movement of the downhole tool in accordance with the formula p c- 2F.C.h 51298361 Fp - synchronization frequency; V is the speed of movement of the device; y is the measurement error; 5 h is the quantization step; i I to Tfr 7R 1G LTz: P L Editor A, Vorovich Compiled by, Sidorov Tehred L. Serdyukova Order 870/32 Circulation 533 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 width of the frequency spectrum of the measured signal; power consumed from the source of information; energy threshold of sensitivity Proofreader A. Obruchar Subscription