RU2620327C1 - Defects diagnostic device inside the buildings made of tube steel - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: defect diagnosis device in the constructions made of the steel pipe, comprising GMR magnetic sensors and data processing unit, GMR sensors are placed on the boards in the form of discs mounted on a common shaft parallel. Each board taken not less than 8 bicomponent GMR sensors placed on the outer circumference of the card equidistant from each other, form a board of at least two groups, two in each board. Wherein the horizontal axis of the bicomponent GMR sensors on each of the boards are perpendicular tubing axis are coaxial and are directed to each pair of oppositely lying sensors toward one another, the vertical axis of the sensors are parallel to the axis of the tubing and parallel to one another, the vertical axis are arranged one above the other sensors to provide necessary precision are coaxial. At the end of the rod information processing unit is placed with the output connector to the control and recording devices.

EFFECT: expansion of the functional capabilities of the device.

7 cl, 8 dwg

Description

The invention relates to devices for identifying and characterizing defects and stress concentration zones in engineering structures of steel pipe steels, including oil and gas gauge threaded pipes used in drilling and extraction of oil products.

Work in the field of improving methods and devices for technical diagnostics of oil and gas well equipment and the practical implementation of their results in order to maintain this equipment in good working condition are becoming increasingly relevant both from the point of view of economic efficiency and environmental safety, since most oil fields and gas are in the late stages of industrial development.

The completeness and objectivity of the study of the technical condition of the wells is determined by the design of the well (availability of tubing, underground equipment, multi-column, etc.), downhole conditions, research technology used by the complex of geographic information systems and technical capabilities of downhole geophysical equipment, a consistent approach to measurements.

To increase the accuracy of determining the thickness and the probability of detecting various defects of the walls of the columns in the wells, it is necessary to expand the capabilities of existing measuring instruments, develop new technologies for geophysical research, improve software and methodological tools for the process of recording and processing geophysical data. Recently, new types of domestic geophysical equipment have been developed and mass-produced for studying the technical condition of wells (threaded oil and gas assortment pipes, for example tubing strings). Created new software and methodological tools for research and data processing can increase the efficiency of geophysical research. However, the information level of the existing complex of technical, software and methodological tools for reliable detection of column defects such as cracks, corrosion intervals, and local violations is still insufficient.

The main damage to oil and gas gauge threaded pipes, such as tubing strings, during research should include a “break in the threaded part”, through damage, brook corrosion, pitting corrosion, etc.

The main methods for monitoring the technical condition of wells include:

- Acoustic and ultrasonic thickness and flaw detection, including Schlumberger USI, acoustic televisions ARKTs-T-1, SAT-4 (NPF Geofizika), AWAK-42 (NPP VNIIGIS), AKTS SV (NPP Geometr) ), Schlumberger scanners - CET-CE / G / J, CET-B B / H / F; Computalog - PET, Baker Atlas - CBT.

Disadvantages of well-known methods for monitoring the technical condition of wells: high requirements for well cleaning and dispersion of well fluid, control performance is low, equipment cost is high.

- Electromagnetic flaw detection (magnetic impulse flaw detectors EMDS-S) (Non-destructive testing. Book 3. Electromagnetic control. Higher school. 1992; "Methodological development of borehole electromagnetic flaw detection of oil and gas wells" V.K. Teplukhin; "Magnetic diagnostics of gas and oil pipelines "A.A. Abakumov, A.A. Abakumov (Jr.), Moscow, Energoatomizdat, 2001).

This method does not allow measuring the size of defects, evaluating their shape, quantity and relative position. Limitations on the sensitivity of this method do not allow detecting local crack-like and corrosion defects.

- Thermometry and flow measurement under injection and inflow. It allows detecting only end-to-end damage to the pipe, which is not enough to assess its resource and choose the optimal method of liquidation.

As you know, in the process, a number of external factors are exposed, the degree of impact of which determines the wear of the pipes, and therefore the occurrence of accidents.

Among the factors that most affect pipe wear, the following factors can be considered the most significant:

- abrasion of the pipe wall when it contacts the well wall and the rod string during tripping operations;

- bursting effects caused by pressure on the inner wall of the pipes of the process fluid;

- the influence of the temperature of the oil-water mixture, as well as temperature differences during heating and cooling of tubing pipes in the process of lifting oil and gas;

- corrosion of the walls of the pipes.

These factors cause the occurrence of deformations, which lead to the destruction of threaded joints, unscrewing and rupture of pipes, in particular tubing string.

Prolonged exposure to deformation leads to a violation of the integrity of the walls of oil and gas pipes and emergency situations.

There are various technical solutions in the field of detection and characterization of defects of steel tubing during drilling and oil recovery.

RU patent for invention No. 2364860 (IPC G01N 27/82, published on 08.20.2009) “Sensor for separating defects into external and internal for a device for monitoring magnetic fluxes of scattering”.

The invention relates to the control of pipelines. The projectile contains a housing, the first and second circumferential spaced apart magnets of opposite polarities located on the shell of the projectile. Magnets provide magnetic saturation of the pipeline zone between them. The first measuring devices are placed on the shell of the projectile between the magnets and are configured to generate signals that respond to the scattering of the flow to provide the first information regarding anomalies on the inner and / or outer surface of the pipeline. The second measuring devices are placed on the shell of the projectile between the magnets and are capable of generating signals that respond to eddy currents induced in the inner surface of the pipeline to provide second information regarding anomalies on the inner surface of the pipeline. The signal processing circuitry is designed to combine the first and second signals. In this case, the second measuring devices are excited only in response to the signals generated by the signal processing circuit. Effect: energy saving.

The main distinguishing feature of the technical solution described in the patent is the determination of the defect orientation on the pipe wall using an eddy current system, and the system is excited only by a signal about the presence of a defect received from the main, insufficiently sensitive sensors (Hall).

The invention RU No. 2382357 (IPC: G01V 3/28, G01N 27/82, publ. 02/20/2010) on a borehole magnetic introscope. The aim of the invention is to expand the functionality, increase the resolution when registering wall defects and features of the production string (perforations, couplings, centralizers, etc.), as well as the sensitivity and reliability of the information received. This goal is achieved by the fact that the magnetic borehole introscope consists of a borehole module and a ground-based diagnostic system containing a geophysical elevator, a geophysical cable, a selsyn, rigidly fixed to the surface of the earth relative to the wellhead, which is a transducer of rotation into an electrical signal designed to measure the movement of the geophysical cable . The downhole module contains: a magnetizing device made in the form of an electromagnet, a magnetic measuring system consisting of magnetically sensitive sensors placed on flexible "skis" between the poles of a dumbbell-shaped magnetic circuit.

In the technical solution for this patent, the magnetizing circuit of the magnetizing device is equipped with interchangeable poles, which makes it possible to control production cores of various diameters using a single magnetic borehole introscope. Magnetosensitive sensors of the main scanning magnetic measuring system are located relative to the magnetizing device and the production string in such a way as to provide maximum sensitivity to the magnetic field component directed along the production string. However, the orientation of the magnetic measuring system during operation may vary. An additional scanning system has been introduced, made in the form of a string of magnetosensitive sensors located on flexible "skis" equipped with permanent magnets of small magnetomotive force, magnetizing a portion of the production string adjacent to the magnetosensitive sensor to a state that does not reach "technical saturation", with the output of each of magnetosensitive sensors connected to one of the information inputs of the on-board controller. An additional scanning system is made in the form of a string of eddy current sensors located on flexible "skis", and the output of each of the eddy current sensors is connected to one of the information inputs of the on-board controller. The use of flexible skis during operation creates additional technical difficulties. The eddy current sensors of the line of the additional scanning system are structurally combined with the magnetic measuring sensors of the main scanning magnetic measuring system. The combination of the measuring system of the magnetic introscope and the system of eddy current sensors increases the noise level in the measuring circuits.

US patent No. 7218102 (IPC G01N 27/72, publ. 13.04.2006) for the invention "Method of non-destructive testing of pipelines and a device based on it." A device for monitoring the integrity of the walls of the pipeline contains a magnetic circuit and at least three permanent magnets: a relatively medium-strength magnet located at one end of the magnetic circuit, a relatively weak magnet located at the other end of the magnetic circuit, and a relatively strong magnet located in the middle between the medium and weak magnets . At least three magnets are selected and arranged so as to create a set of magnetic fields in the pipe wall containing the first magnetic field suitable for detecting anomalies associated with metal loss, and a second magnetic field suitable for detecting anomalies associated with mechanical impact on the pipe wall . Preferably, the first magnetic field is larger in magnitude than 120 Oe, and the second magnetic field is larger in size in the range of 40-80 Oe.

The known device implements a method based on the method of magnetic flux scattering (MFL). The main distinguishing feature of the invention is a three-pole magnetic system, which creates areas with different levels of magnetization in the control object. It is argued that the identification of areas of metal subject to mechanical stress is more effective in an unsaturated state, when the field value lies in the range of 40-80 Oe (~ 2400-6400 A / m). It is proposed that tense metal sections be detected in the zone of a small field of the magnetic system. Identification of defects in the form of metal losses and cracks is in the zone of a large field in which the metal is in a state of saturation (more than 120 Oe). The main disadvantage is the uncontrolled influence of technological and operational magnetic inhomogeneities.

Also known is a magnetic borehole introscope MI 50 (A.A. Abakumov, A.A. Abakumov (ml.), Bazhenov V.V. et al. Technology of magnetic introscopy for flaw inspection of production casing wells. "Interval" No. 10, 2008) . The device is designed for non-destructive testing of casing strings of wells. Tasks to be solved: determination of casing string defects in the form of through and through holes and cracks; determination of corrosion intervals for casing strings of wells; determination of casing thickness; determination of the actual position of the casing perforation intervals; binding of column defects to a geological section. It is characterized by functional simplicity, relatively low cost and good adaptability.

Types of diagnosed pipes - casing strings of oil wells (hot rolled pipes, steel of strength group “D” (analogue of CT45).

To remove and install the pole pieces, you will need to use the key for the hexagon screws provided. Removing the pole pieces is necessary to replace magnetically sensitive sensors.

The disadvantage of MI 50 is the lack of ability in identifying stress concentration zones (ZKN) in the tubing couplings and areas of small (2-3 mm) tubing shortfalls.

Known electromagnetic flaw detector of steel pipes in wells according to RU patent for invention No. 2176317 (IPC: ЕВВ 47/00, G01N 27/83, publ. 11/27/2001). The technical result of the known solution is to obtain additional information about the places of breaks in the casing and disconnections in the casing couplings through tubing by measuring the natural constant magnetic field at the same time as determining the wall thickness of the casing. To do this, the radiation of probing bipolar electromagnetic pulses is produced using a generator coil and the measurement of the emf induced in the receiving coil by the decay of the electromagnetic field caused by the probe pulses. Then, the values of the emf obtained after the positive and negative generator pulses are subtracted. Additionally measure the intensity of the natural magnetic field along the pipe. Why add up the measurements of the emf on the receiving coil in two half cycles of the generator coil. In this case, the signals caused by the pulses of the probe current having different polarity are subtracted, and the signals caused by the natural magnetic field are added. The magnitude of the resulting signal corresponding to the magnitude of the rate of change of the natural magnetic field is judged on the presence or absence of gaps in the column.

The above-mentioned well-known technical solutions find application mainly in the field of field and trunk oil pipe inspection, and are intended for implementation as part of autonomous flaw detector shells.

The disadvantages of the known technical solutions are:

- the use of an external magnetic field and devices for its creation, the complexity of the design of the probing projectile;

- the need to take into account fluctuations in the internal magnetic field;

- lack of registration of a pre-upset condition;

- lack of registration of shortfalls in the tubing couplings.

Closest to the proposed technical solution for the combination of essential features is the "Method of magnetic flaw detection and measuring device for its implementation" according to patent RU No. 2319955, selected as a prototype. The invention relates to the field of flaw detection and can be used to detect various types of heterogeneities and determine the nature of these heterogeneities, their spatial orientation in steel columns of oil and gas wells. Essence: the method uses the property of the formation in ferromagnets of crystallographic directions of easy magnetization, which determine the direction of the magnetic field. A multi-element magnetic transducer measures the direction of the magnetic field by converting the angle of the magnetic induction vector to a specific emf value proportional to the angle of induction. After that, the analysis of the signals.

The measuring device contains a set of identical, not electrically connected, magnetic field sensors, sensitive only to the direction of the magnetic field and insensitive to the value of the magnetic field strength. The sensors are evenly distributed over at least three levels, in the form of square cells around the perimeter of the circle. The measuring device also includes an electronic switch, a precision differential amplifier and an analog-to-digital converter. Improving the accuracy in determining zones of various types of defects is achieved by the complex measurement of the character of the magnetic anisotropy of the pipe walls due to the use of high-tech GMR sensors as magnetic field sensors that are sensitive only to a change in the direction of the magnetic field (a change in the angle between the direction of the magnetic field and the normal to surfaces of a magnetic transducer / Handbook of Elementary Physics N. N. Koshkin, M. G. Shirkevich, 7th stereotyped edition, M., Nauka, Main Edition physical and mathematical literature, 1976, pp. 157-158) and insensitive to its tension. A large air gap (up to 50 mm) between the sensor surface and the analyzed surface is allowed; high accuracy is also determined by the fact that the magnetic field sensors of this type have a constant temperature coefficient.

The disadvantages of the known device are:

- lack of sensitivity to the magnitude of the magnetic field, which can lead to the omission of the zones of pre-breakthrough state of pipe columns;

- low sensitivity when fixing through and through isometric holes in the walls of tubing with a diameter of 8, 6, 4 mm;

- insufficient sensitivity when fixing shortfalls of 2.5-3.2 mm in the tubing pipe couplings with a diameter of up to 60 mm and in low-quality areas of threaded tubing pipe couplings and couplings.

The differences of the invention from the prototype:

- the use of 2-component sensors that capture the amplitudes of the signals along the corresponding axes;

- the use of alignment and orthogonality of the axes of the sensors, which allows to carry out the gradient and tensor processing of the received field signals with the necessary accuracy and determine the magnitude of the shortfalls;

- the use of 2 groups of paired (identical) sensors, which increases the accuracy and reliability of measurements;

- the use of the internal magnetic field of the pipe, and not the external magnetizing field.

The task to which the invention is directed is to create a device for diagnosing defects and zones of ZKN (zones of stress concentration) in engineering structures of pipe steels, in particular in tubing, with the following characteristics:

- the possibility of fixing shortfalls of tubing tubing with a diameter of up to 60 mm in the couplings with a magnitude of shortfalls of 2.5-3.2 mm or more, a quantitative characteristic of the changing value of shortfalls of at least 2.5 mm;

- the ability to fix through isometric holes in the walls of the tubing with a diameter of 8, 6, 4 mm;

- the possibility of identifying and evaluating SCZs that are abnormal in the coupling joints and tubing walls that are hazardous in emergency situations;

- the ability to identify areas of poor quality threaded pipe joints and couplings;

- the ability to identify restrictions caused by changes in the overall dimensions of the tubing itself, including the size of ovality, narrowing of the bore, the presence of pipe sections difficult to pass, etc.

The technical result of the invention is to expand the functionality of the device for the diagnosis of defects and zones of ZKN in pipe steels with threaded joints, in particular in the tubing.

The technical result is achieved by the fact that in the device for diagnosing defects in pipe steel structures, including GMD magnetic sensors and an information processing unit, GMR sensors are placed on boards in the form of disks mounted on a single rod parallel to each other, with at least with 8 two-component GMR sensors placed along the outer circumference of the board at an equal distance from each other, the boards form at least two groups, two boards in each. Moreover, the horizontal axes of all two-component GMR sensors on each of the boards are perpendicular to the tubing axis, are aligned and directed for each pair of oppositely lying sensors towards each other, the vertical axes of all sensors are parallel to the tubing axis and parallel to each other, vertical axes located one below the other sensors, for ensure the necessary accuracy of alignment. At the end of the rod there is an information processing unit with an output connector for connecting to a control and recording device.

Additional features of the invention:

- the distance between the boards in each group is not more than 5 mm;

- the diameter of the rod is not more than 4 mm;

- the distance between each pair of boards is not more than 50 mm;

- the location of the sensors on one of the boards in each group of boards is shifted relative to the location of the sensors on the other board of this group by an angle equal to 45 °;

- the information processing unit includes an analog-to-digital converter, the input of which receives input signals from GMR sensors, connected to an interface converter and a communication converter with a USB port, which are in turn connected to a power supply, and the communication converter with a USB port is also connected to a signal recording unit, the output of which is connected to the output connector;

- as a control device can be used in-line geophysical flaw detector, in particular a magnetic introscope.

The essence of the invention is illustrated by the following drawings: FIG. 1, which shows the proposed device (a - the location of the boards with GMR sensors; b - the location of the GMR sensors on the boards; c - the direction of the axes of the sensors on 2 selected boards in the upper and lower groups),

Where:

1-4 - boards;

5 - information processing unit;

6 - 2-component sensors, the horizontal axis of which is perpendicular to the axis of the pipe, and the vertical ones are parallel to the axis of the pipe mounted on the upper and lower groups of boards;

7 - a core;

8 - output connector

FIG. 2, in which an information processing unit 5 is shown,

            Where:

6 _1-32 - two-component sensors;

9 _1-32 - sensor amplifiers;

10 - sensor block;

11 - analog-to-digital Converter;

12 - interface converter;

13 - communication converter;

14 - power supply;

15 is a block recording signals

FIG. 3, which shows the connection diagram of the proposed device to the control and recording devices,

Where:

16 - tap information lines of the logging cable to the ground panel;

17, 18 - information lines of the wireline cable;

19 - power supply ground panel;

20 - power source of the proposed device;

21 - the proposed device;

22 - core wire, through which there is power;

23 - ground panel;

24 - odometer;

25 - personal computer.

Output parameters of power supply 19: voltage 200 V, current 0.25 A (source 19 operates in voltage stabilization mode);

The output parameters of the power source 20: voltage 200 V, current 0.4 A (source 20 operates in the mode of current stabilization),

FIG. 4, which shows the control of the proposed device using a magnetic introscope through the eddy current module,

Where:

26 - geophysical cable;

27 - logging elevator with reference to the distance;

28 - a computer for recording distance samples, control ligament;

29 - wireline cable;

30 - memory for storing signals;

31 - in-tube introscope of a galvanomagnetic field;

32 - eddy current field unit;

33 - meter internal pipe magnetic field,

FIG. 5, which shows graphs of a longitudinal gradient,

FIG. 6, which shows a plan of isolines of the longitudinal gradient of the transverse field throughout the pipe,

FIG. 7, which shows the primary plan of the isolines of the under-rotation of 2.27 cm,

FIG. 8, which shows a primary plan of 3.61 cm undercuts.

The device for diagnosing defects in the tubing includes GMD magnetic sensors 6 and an information processing unit 5. GMD sensors 6 are placed on boards 1-4 in the form of disks mounted on a single rod 7 parallel to each other, with at least 8 two-component GMDs located on each board sensors placed along the outer circumference of the board at an equal distance from each other, boards 1-4 form at least two groups, two boards in each. The horizontal axes of all two-component GMR sensors on each of the boards are perpendicular to the axis of the tubing and are aligned for each pair of oppositely lying sensors towards each other. The vertical axes of all sensors are parallel to the axis of the tubing and parallel to each other, vertical axes located one below the other sensors, to ensure the necessary accuracy of the pine.

At the end of the rod 7 there is an information processing unit 5 with an output connector 8 for connection to a control and recording device.

The distance between the boards in each group is not more than 5 mm, the distance between each pair of boards is not more than 50 mm.

The diameter of the rod is not more than 4 mm.

The location of the sensors on one of the boards in each group of boards can be shifted relative to the location of the sensors on the other board of this group by an angle equal to 22.5 °.

The information processing unit 5 includes a 32-channel analog-to-digital converter 11, to the input of which there are input signals from GMP sensors 6, connected to an interface converter 12 and a communication converter with a USB port 13, which are in turn connected to a power supply unit 14, the converter communication with the USB port 13 is also connected to the signal recording unit 15, the output of which is connected to the output connector.

An introscope, for example, MI-50, can be used as a control device.

The use of GMR sensors 6 makes it possible to detect critically dangerous shortfalls in tubing couplings by the number of unscrewed threads and characterize them quantitatively with satisfactory accuracy, as well as to fix low-quality zones of threaded joints.

The use of uniaxial GMR sensors 6, turned towards each other, whose axes are perpendicular / parallel to the axis of the pipe, also makes it possible to detect isometric defects in tubing walls with a diameter of 8 and 6 mm.

Static device

The circuitry and methodological solutions for the use of GMR sensors 6 are proposed when registering SCZ in conjunction with models of galvanomagnetic and eddy current introscopes.

As GMR, heat-resistant sensors with indexing SpHBx, SpHCx, SpHDx are used.

SpHxx - a series of bipolar spin valves of the GMR sensor has a full-bridge design (for operation in the range +/- 0.4 mT +/- 0.7 mT). It provides better performance compared to the known GMR sensors 1 and 2, improved linearity (usually 1%), greater thermal stability and low hysteresis (usually 0.2%). They operate at temperatures from -40 ° C to 125 ° C. This series, consisting of SpHBx, SpHCx and SpHDx, has different sensitivity, the most sensitive is SpHBx.

The signals from the sensors are digitized and transmitted in the form of a code via the autonomous interface of the RS-485 converter with reference to the distance traveled, which is recorded by an electronic odometer.

The sensors are placed in a non-magnetic casing with a diameter of 36 mm, length up to 500 mm.

The device is powered by an external DC source with a rated voltage of 100 V (70 ... 150 V) and a maximum output current of 100 mA.

Device in dynamics

In the case of using a ligament, the introscope module, the eddy current module and the GMR module, the latter is connected to the eddy current module block via a common bus. The device is controlled, namely, the beginning of the recording of the signal on the medium and the end of the file recording is performed by a magnetic introscope through the eddy current module (see Fig. 4).

Recording a signal from GMP sensors 6 is performed on a portable medium of any of the types currently existing (Flash memory, SD card, etc.) with a capacity of 64 GB. Having received a signal to start recording from a magnetic introscope, the device starts recording a signal. Similarly, the signals of the end recording command are received.

The obtained records are processed by the methods of vector and tensor analysis. The gradients obtained during processing (for example, longitudinal derivatives) and the principal axes of the derivatives in several (in 8) horizontal and vertical planes characterize bends, twists, dents, cracks, as well as ZKN, shortcomings in couplings and local defects.

Primary data when using horizontal and vertical components of 2-component sensors:

- horizontal sensors in the upper group (1) in the upper board: X11a ... U24a;

- horizontal sensors in the upper group (2) in the lower board: X11b ... U24b;

- vertical sensors in the upper group (6) in the upper board: Z11 ... Z24a;

- vertical sensors in the upper group (7) in the lower board: Z 11b ... Z 24b.

Similarly, the primary data in the upper and lower boards of the lower group of sensors are determined.

Based on the measured primary data, horizontal gradients are calculated, for example, for the upper group of sensors according to the formulas:

(X1a-X13a) / ΔX ...: (X11b - U24b / .ΔX,

and vertical gradients, for example, for the upper group of sensors:

(Z11a -. Z24a) / Δ Z ... (Z 11b - Z 24b.) / Δ Z

Gradients are used to identify local defects and stress concentration zones.

Next, the values of the modules on the boards are calculated:

- Modules on the upper board of the upper group:

for example, M11a is the square root of the sum of squares Z11a and X11a; M11b is the square root of the sum of the squares Z11b and X11b.

The modules on the bottom board are defined in the same way.

Modules are used to highlight non-through isometric defects, perforations, local stress concentration zones and discontinuities. In this case, to suppress noise, the ratio of the modules, for example, M11a / M11b, or their difference (M11a-M11b) is calculated.

Tensor parameters

The gradients obtained during processing based on tensor processing allow us to calculate the values of the principal axes of heterogeneities and their direction in 8 vertical planes. They characterize pipe defects and deformations in the form of bends, twisting, longitudinal dents, cracks, as well as SCZ and shortfalls in the couplings.

,

,

,

(без индексации а, б) в одной из вертикальных плоскостей (X11, Х13, Z13, Z31) и пропорциональные им величины нормальных и касательных напряжений определяются из соотношений:For example, the main axis of the field gradients

,

,

,

(without indexing a, b) in one of the vertical planes (X11, X13, Z13, Z31) and proportional to them normal and tangential stresses are determined from the relations:

In practically used design:

ΔX = ΔY = 0.038 m, ΔZ = 0.050 m

,

и

,

усредняются.The obtained values

,

and

,

are averaged.

The principal axes in other vertical planes are defined in a similar way.

The direction of the main axes is determined by the classical formulas of tensor analysis on the plane (see Lectures on tensor analysis. M: Publishing House of Moscow University, 1986, 264 pp.).

The following are examples of the application of the proposed device when conducting preliminary bench tests. Processing is based on longitudinal derivatives.

The stand consists of two pieces of tubing tubing with a diameter of 60 mm, wall thickness of 5 mm and a length of 3 meters each, connected by a sleeve. The total length of the screwed segments is 6 meters.

On the graphs of the longitudinal gradient and on the plans of the isolines, a solid vertical line (i.e., for all sensors) fixes the position of the coupling and the under-rotation of the pipe joints of the tubing (see Fig. 5).

Local features (i.e., along the axes of the sensors that are suitable in orientation) fix the magnetic inhomogeneities of the pipe (see Fig. 6, which shows the plan of the isolines of the longitudinal gradient of the transverse field throughout the pipe).

In FIG. Figure 7 shows the primary plan of the isolines of the under-rotation of 2.27 cm.

The distance between the minima of the longitudinal gradient graphs in the area of the tubing pipe joint for the sensors selected along the GMR axis corresponds to the distance between the pipe joints and can be measured with a ruler with an error of up to one thread turn, i.e. no worse than +/- 1 mm (see Figs. 5 and 6).

The complex nature of the anomalies of the isolines of the longitudinal gradient with the disappearance of one of the extremes indicates the influence of the quality of the threaded joints of the tubing with the sleeve.

An example of calculating under-rotation when manually unscrewing a pipe from a sleeve:

The distance between the minima of the longitudinal gradient at the maximum possible twisting of 2.27 cm, when unscrewing the pipe is 3.61 cm. The calculated change in the distance between the ends of the pipes = 3.61-2.27 = 1.34 cm. The number of turns corresponding to an increase in under-rotation, t .e. the change in the distance between the ends of the pipes = 13.4 mm / 2.5 mm (the distance between the turns of thread on the pipes) = 5.36, i.e. 5 turns. (A value of 2.5 mm is used - the distance between the threads on the pipes).

The advantages of the invention before the known analogues:

- The use of GMR sensors makes it possible to detect shortcomings that are critical in the number of screwed thread turns with satisfactory accuracy and make timely decisions on repairing sections of pipe threaded joints, for example tubing pipes;

- The use of GMR sensors at the optimal position of their axes makes it possible to detect local isometric defects with a diameter of 8 and 6 mm in the walls of the pipes, in particular in the walls of the tubing;

- The use of GMR sensors allows you to fix the magnetic inhomogeneities of the pipe, which can be dangerous if they are associated with excessive mechanical stresses;

- The use of GMR sensors allows fixing defects in threaded couplings of the coupling with tubing pipes, which increase the level of mechanical stresses and the risk of rupture of the pipe string.

Thanks to the use of the proposed device, difficulties are minimized (namely, the absence of absolute measurements, the need for magnetization reversal, difficulties in measuring field gradients, displacement of the operating point, scatter of the measured parameters) of use in magnetometers or magnetometers-gradiometers. As a result, due to the higher speed compared to flux probes, greater accuracy and detail in solving flaw detection tasks are achieved.

Thus, thanks to the proposed design, the functionality of the device for diagnosing defects and stress concentration zones in threaded joints of steel oil and gas pipes, including tubing, is expanded.

Claims (8)

1. A device for diagnosing defects in structures made of pipe steels, including GMR magnetic sensors and an information processing unit, characterized in that the GMR sensors are placed on the boards in the form of disks mounted on a single rod parallel to each other, and on each board there are at least 8 two-component GMR sensors located on the outer circumference of the board at an equal distance from each other, the boards do not form less than two groups, two boards in each, and the horizontal axes of all two-component GMR sensors on each of the boards are perpendicular to the tubing axis, are aligned and directed for each pair of oppositely lying sensors towards each other to each other, the vertical axes of all sensors are parallel to the tubing axis and parallel to each other, the vertical axes of the sensors located under each other to ensure the necessary accuracy are aligned, an information processing unit with an output connector for connecting to the control and recording devices is located on the end of the rod. 2. The device according to claim 1, characterized in that the distance between the boards in each group is not more than 5 mm. 3. The device according to p. 1, characterized in that the diameter of the rod is not more than 4 mm 4. The device according to claim 2, characterized in that the distance between each pair of boards is at least 50 mm. 5. The device according to claim 1, characterized in that the location of the sensors on one of the boards in each group of boards is shifted relative to the location of the sensors on the other board of this group by an angle equal to 22.5 °. 6. The device according to claim 1, characterized in that the information processing unit includes an analog-to-digital converter, the input of which receives input signals from GMR sensors, connected to an interface converter and a communication converter with a USB port, connected in turn to the power supply moreover, the communication converter with the USB port is also connected to the signal recording unit, the output of which is connected to the output connector. 7. The device according to claim 1, characterized in that an introscope can be used as a control device.

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