Petroleum drill rod thread detection device and detection method based on high-frequency eddy current

Abstract

The invention discloses a petroleum drill rod thread detection device and detection method based on high-frequency eddy current, belongs to the technical field of drill rod nondestructive detection, and solves the problems that an existing drill rod thread nondestructive detection mode is low in detection precision and incomplete in detection. The petroleum drill rod thread detection device based on the high-frequency eddy current comprises a drill rod external thread scanning device and a drill rod internal thread scanning device. The drilling rod external thread scanning device comprises an external thread detection assembly and an external thread fixing assembly. The drill rod internal thread scanning device comprises an internal thread detection assembly and an internal thread fixing assembly. The external thread detection assembly and the internal thread detection assembly are respectively provided with a plurality of high-frequency eddy current probes, and the plurality of high-frequency eddy current probes are electrically connected with the detection system. According to the invention, when the external thread of the drill rod is scanned, the external thread detection assembly and the external thread fixing assembly are respectively clamped at two sides of the external thread of the drill rod, and a high-frequency eddy current probe on the external thread detection assembly comprehensively scans the external thread of the drill rod.

Description

Technical Field

[0001] The present invention relates to the technical field of non-destructive testing of drill pipes, and particularly to a drill pipe thread detection device and method based on high-frequency eddy current. Background Art

[0002] Drill pipes play an important role in the exploration, development, and production of oil and gas. The threads at the end joints of drill pipes are used for connecting drill pipes to each other. These threads bear the working load of the drill pipes during their service life. Therefore, the detection of these threads is extremely important. Due to the extremely harsh working conditions of drill pipes during their service life, they are affected by the coupling effects of factors such as complex formation conditions, harsh corrosive media, fluid erosion, complex movements, and combined movement loads of tension, compression, bending, and torsion. After long-term use, drill pipe threads will cause various thread failure problems such as cracks at the root of drill pipe threads, broken threads, unthreading, corrosion, and taper changes in the thread area, which will further lead to major safety accidents such as connection failures during the service life of drill pipes.

[0003] Currently, the main detection techniques for threaded drill pipes include commonly used detection methods such as visual inspection, magnetic flux leakage detection, ultrasonic detection, and magnetic particle detection. Manual visual inspection is suitable for the detection of small batches of drill pipe threads. Since small cracks in the threads are often filled and covered with oil stains, and the viewing angle of the female threads of drill pipes is limited, it is difficult to detect small cracks. Magnetic flux leakage detection requires magnetization of drill pipe threads, and there are certain blind spots in both the magnetized part and the detected part, making it difficult to detect small cracks and resulting in low detection accuracy. Ultrasonic detection uses echoes to detect defects at the bottom of drill pipe threads. Although it can detect deeper defects, due to the complex structure of drill pipe threads, only some defects at the bottom can reflect ultrasonic waves back to the probe, resulting in a relatively high missed detection rate. Moreover, ultrasonic detection requires a coupling agent, which limits the detection efficiency to a certain extent. Magnetic particle detection has relatively high detection accuracy, but since imaging and defect observation still need to be completed manually, the efficiency is low.

[0004] In the Chinese invention patent with the authorization announcement number CN112114030B, a drill pipe thread detection device and method based on ferrite eddy current thermal imaging are disclosed. In this patent, an infrared thermal imager is used to record the temperature changes on the surface of drill pipe threads, and then the temperature changes are used to judge the defect positions of drill pipes. Although this detection method has high detection efficiency, it requires deep cleaning of drill pipe threads before detection, and the detection equipment has high costs, a complex detection device, and it is difficult to detect the internal threads of drill pipes.

[0005] In the Chinese invention patent with the publication number CN112815857A, a drill pipe thread detection device and method are disclosed. In this patent, the detection is mainly focused on the morphological parameters such as the tooth height, tooth width, pitch, taper, large end diameter, and cone length of the external threads of phosphated drill pipes, and it cannot detect the thread defects of drill pipes.

[0006] In summary, the defects of drill pipe threads are often filled and covered with oil stains, making it difficult to visually detect them; the detection accuracy of ultrasonic testing and magnetic flux leakage testing is not high, and it is difficult to detect minor defects, posing a significant safety hazard. The eddy current thermal imaging detection method requires in-depth cleaning of the threads, and the detection device is complex, costly, and unable to detect internal threads. Therefore, it is of practical significance to develop a high-efficiency, high-precision, and low-cost detection device for drill pipe internal and external threads. Summary of the Invention

[0007] Aiming at the deficiencies in the prior art, the present invention provides an oil drill pipe thread detection device and detection method based on high-frequency eddy current, which solves the problems of low detection accuracy and incomplete detection in the existing non-destructive detection methods for drill pipe threads.

[0008] In the first aspect, to achieve the above object, the technical solution adopted by the present invention is as follows: An oil drill pipe thread detection device based on high-frequency eddy current includes an external thread scanning device for drill pipes and an internal thread scanning device for drill pipes; a plurality of high-frequency eddy current probes are provided on both the external thread scanning device for drill pipes and the internal thread scanning device for drill pipes, and the plurality of high-frequency eddy current probes are electrically connected to the detection system respectively; the external thread scanning device for drill pipes is connected to the external thread of the drill pipe for scanning the defects of the external thread of the drill pipe; the internal thread scanning device for drill pipes is connected to the internal thread of the drill pipe for scanning the defects of the internal thread of the drill pipe.

[0009] Furthermore, the external thread scanning device for drill pipes includes a first skeleton ring, and an external thread detection component and an external thread fixing component are movably arranged on the first skeleton ring; the external thread detection component and the external thread fixing component are respectively clamped on both sides of the external thread of the drill pipe; The internal thread scanning device for drill pipes includes a second skeleton ring, and an internal thread detection component and an internal thread fixing component are movably arranged on the second skeleton ring; the internal thread detection component and the internal thread fixing component are respectively abutted against both sides of the internal thread of the drill pipe; The high-frequency eddy current probes are arranged on the external thread detection component and the internal thread detection component.

[0010] In this solution, when scanning the defects of the external thread of the drill pipe, the external thread detection component and the external thread fixing component in the external thread scanning device for drill pipes are respectively clamped on both sides of the external thread of the drill pipe, and the high-frequency eddy current probes on the external thread detection component are used to comprehensively scan the defects of the external thread of the drill pipe; when scanning the defects of the internal thread of the drill pipe, the internal thread detection component and the internal thread fixing component in the internal thread scanning device for drill pipes are respectively supported on both sides of the internal thread of the drill pipe, and the high-frequency eddy current probes on the internal thread detection component are used to comprehensively scan the internal thread of the drill pipe, with high scanning accuracy and fast speed.

[0011] Further, the external thread detection component includes a detection block fixing bracket fixed to the inner side of the first skeleton ring; an external thread detection block is installed on the detection block fixing bracket. The side of the external thread detection block close to the external thread of the drill pipe is tapped with threads, and a high-frequency eddy current probe is installed on the thread teeth of the external thread detection block; The external thread fixing component includes a lifting adjustment cylinder and an external thread support block. The lifting adjustment cylinder is movably connected to the inner side of the first skeleton ring; the top of the external thread support block is inserted into the lifting adjustment cylinder, and a bolt on the side wall of the lifting adjustment cylinder fixes the external thread support block; the side of the external thread support block close to the external thread of the drill pipe is tapped with threads.

[0012] In this solution, the sides of the external thread detection block and the external thread support block with threads are respectively connected to both sides of the external thread of the drill pipe. During the detection process, the first skeleton ring is rotated, and the first skeleton ring drives the two to move along the external thread of the drill pipe, thereby comprehensively scanning the external thread of the drill pipe. The coverage area during the scan is large, avoiding missing areas. The external thread support block can be axially adjusted up and down relative to the lifting adjustment cylinder, and its position can be flexibly adjusted and fixed when installing the external thread support block.

[0013] Further, a first slider is connected to the side of the detection block fixing bracket close to the lifting adjustment cylinder, and a first slide rail is connected to the side of the lifting adjustment cylinder close to the detection block fixing bracket. The first slider is slidably connected to the first slide rail; A regulating rod is connected to the side of the lifting adjustment cylinder away from the detection block fixing bracket. The regulating rod is movably arranged in the chute of the first skeleton ring and is connected to the chute through a bolt; Elastic band fixing openings are provided on both the detection block fixing bracket and the external thread support block, and an elastic band is connected between the two elastic band fixing openings.

[0014] In this solution, since the position of the external thread of the drill pipe is conical, the distance between the external thread detection block and the external thread support block needs to be adjusted radially during each scan; during the scan, the external thread support block moves radially under the action of the tension of the elastic band, so that the external thread detection block always fits the external thread of the drill pipe; the design of the first slider and the first slide rail can ensure the accuracy and stability of the radial movement.

[0015] Further, a circuit board accommodation groove is provided on the external thread detection block, and a circuit board cover is installed on the circuit board accommodation groove through screws; a wire routing groove is provided on one side of the circuit board accommodation groove, and a cable fastening cover is installed on the wire routing groove through screws.

[0016] In this solution, the probe circuit board is arranged in the circuit board accommodation groove, and the circuit board cover encapsulates the probe circuit board; the cable for connecting the probe circuit board passes through the wire routing groove, and the cable fastening cover can fix the cable to avoid damage to the connection structure between the cable and the probe circuit board when the external thread detection block rotates.

[0017] Furthermore, the internal thread detection component includes a detection block fixing block, which is movably connected to the second skeleton ring; an internal thread detection block is installed on the detection block fixing block, and threads are tapped on the side of the internal thread detection block close to the internal thread of the drill pipe; a high-frequency eddy current probe is installed on the thread teeth of the internal thread detection block; The internal thread fixing component includes an adjusting frame, which is connected to the second skeleton ring; an internal thread support block is connected to the bottom of the adjusting frame, and threads are tapped on the side of the internal thread support block close to the internal thread of the drill pipe.

[0018] In this solution, the internal thread detection block and the internal thread support block respectively support on both sides of the internal thread of the drill pipe. During detection, rotating the second skeleton ring drives the two to rotate, and during rotation, the high-frequency eddy current probe on the internal thread detection block detects the internal thread of the drill pipe.

[0019] Furthermore, a second slide rail is connected to the side of the detection block fixing block close to the adjusting frame, and a second slider is connected to the side of the adjusting frame close to the detection block fixing block; the second slider is slidably connected to the second slide rail; a spring is arranged between the detection block fixing block and the internal thread support block; The top of the second slider is connected to the second skeleton ring through a rod.

[0020] In this solution, the spring drives the detection block fixing block to move radially along the direction of the second slide rail through elastic force, so that the internal thread detection block fits with the internal thread of the drill pipe to be measured.

[0021] Furthermore, the high-frequency eddy current probe includes two copper coils arranged side by side, and two ferrite cores are respectively fixed inside the two copper coils; the two copper coils are connected to the detection system through a bridge-type adjustment circuit.

[0022] In this solution, the two copper coils are connected to a bridge-type conditioning circuit. When there is a defect at the bottom of one of the coils, the impedance of the coil changes, and the balance of the bridge is broken, so that the detected defect can be responded and output. The high-frequency eddy current probe composed of the copper coil and the ferrite core has higher spatial resolution; the ferrite core has high magnetic permeability, which can converge the magnetic induction lines generated by the copper coil to enhance the magnetic field generated by the copper coil and improve the sensitivity of eddy current detection; the inductance of the copper coil is between 0.1 - 50uH, the resistance is between 0.1 - 10Ω, the L∶R ratio is high, and the excitation signal frequency range is between 100kHz - 3MHz.

[0023] Furthermore, the detection system includes a probe circuit board, an eddy current detection circuit board and a host computer. The probe circuit board is connected to the copper coils of the high-frequency eddy current probe through a bridge-type adjustment circuit; the eddy current detection circuit board is electrically connected to the probe circuit board, and the host computer is electrically connected to the eddy current detection circuit board; The eddy current detection circuit board includes a pre - circuit, a system - level chip circuit, and an alarm unit that are connected in sequence; the pre - circuit is electrically connected to the probe circuit board, and the system - level chip circuit is electrically connected to the upper computer.

[0024] In this solution, the pre - circuit realizes the processing of the excitation signal and the eddy current signal; the system - level chip circuit realizes the control of the entire circuit board, can generate excitation signals with different waveforms, amplitudes, and frequencies, obtains the real part and the imaginary part of the induction signal through the collected voltage signal, and then analyzes to obtain the required impedance change signal and sends it to the upper computer.

[0025] In a second aspect, based on the oil drill pipe thread detection device based on high - frequency eddy current provided in the first aspect, the present invention provides an oil drill pipe thread detection method based on high - frequency eddy current, including the following steps: Step 1: Connect the probe circuit board and the eddy current detection circuit board; Step 2: Install an external thread scanning device or an internal thread scanning device on the drill pipe; Step 3: Set the alarm threshold of the alarm unit and the parameters of the high - frequency eddy current probe in the upper computer; after aligning the high - frequency eddy current probe with the thread position without defects on the drill pipe, click to set the balance center; Step 4: Start the detection program, rotate the external thread scanning device or the internal thread scanning device of the drill pipe to start scanning. When the high - frequency eddy current probe detects a defect signal, the system - level chip circuit controls the alarm unit to alarm; Step 5: After the scanning is completed, remove the external thread scanning device or the internal thread scanning device of the drill pipe, export the detection data by the upper computer and perform scanning data processing, and the detection ends.

[0026] The beneficial effects of the present invention are: In the oil drill pipe thread detection device based on high - frequency eddy current provided by the present invention, when detecting the external thread, the external thread detection block and the external thread support block are clamped on both sides of the external thread of the drill pipe, and the first skeleton ring drives the two to rotate one week. During the rotation, the high - frequency eddy current probe on the external thread detection block scans the external thread of the drill pipe. The scanning efficiency is high, the scanning range is wide, and there will be no missed dead angles.

[0027] The detection accuracy of the high-frequency eddy current probe is high; a ferrite with high magnetic permeability is inserted into the copper coil. The ferrite has a high magnetic permeability to converge the magnetic field, making the magnetic field generated by the coil stronger, increasing the inductance of the coil. The copper coil with a larger diameter can reduce the coil resistance and improve the quality factor of the coil. The copper coil has a small aperture and higher spatial resolution. The high-frequency excitation signal enhances the skin effect of the eddy current. The differential coil design can improve the detection sensitivity and reduce the lift-off effect. This detection method can detect tiny defects on the thread surface. The detection efficiency of the high-frequency eddy current probe is high; compared with the traditional drill pipe thread detection device, high-frequency eddy current detection can be completed in a very short time, does not require a coupling agent, realizes non-contact measurement, and will not affect the thread surface and cause no pollution to the environment. The designed external thread detection block and internal thread detection block both contain 16 high-precision high-frequency eddy current probes, which can simultaneously scan 16 thread positions, output 16-channel data, and realize the efficient scanning of oil drill pipe threads.

[0028] The internal and external thread detection of the female and male threads of the oil drill pipe is realized. The drill pipe internal thread scanning device and the drill pipe external thread scanning device are designed respectively for the female and male threads of the oil drill pipe; by replacing different external thread detection blocks and internal thread detection blocks, the thread teeth can be adapted to different drill pipes, and the overall device can also be adjusted accordingly, with strong versatility. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of the drill pipe external thread scanning device assembled on the drill pipe external thread in the present invention; Figure 2 It is a schematic structural diagram of the drill pipe external thread scanning device in the present invention; Figure 3 It is a schematic structural diagram of the drill pipe external thread scanning device removing the first skeleton ring in the present invention; Figure 4 It is a schematic structural diagram of the external thread detection block in the present invention; Figure 5 It is a schematic structural diagram of the drill pipe internal thread scanning device in the present invention; Figure 6 It is a schematic structural diagram of the internal thread detection component in the present invention; Figure 7 It is a schematic structural diagram of the internal thread detection block in the present invention; Figure 8 It is a schematic structural diagram of the high-frequency eddy current probe in the present invention; Figure 9 It is a schematic structural diagram of the detection system in the present invention; Figure 10 It is a flow control diagram of the detection system in the present invention.

[0030] Reference Signs: 1. Drill pipe; 2. External thread scanning device for drill pipe; 21. First skeleton ring; 22. External thread detection component; 221. Detection block fixing frame; 222. External thread detection block; 223. First slider; 224. Circuit board cover; 225. Cable buckling cover; 23. External thread fixing component; 231. Lifting adjustment cylinder; 232. External thread support block; 233. First slide rail; 234. Adjusting rod; 24. Rubber band fixing port; 25. Rubber ring; 3. Internal thread scanning device for drill pipe; 31. Second skeleton ring; 32. Internal thread detection component; 321. Detection block fixing block; 322. Internal thread detection block; 323. Second slide rail; 33. Internal thread fixing component; 331. Adjusting frame; 332. Internal thread support block; 333. Second slider; 34. Spring; 4. High-frequency eddy current probe; 41. Ferrite; 42. Copper coil; 5. Eddy current detection circuit board; 6. Power supply; 7. Host computer. Specific embodiments

[0031] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The specific embodiments of the present invention are described below to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0032] Embodiment 1 As Figures 1 - 9 shown, this embodiment provides a thread detection device for oil drill pipes based on high-frequency eddy current; this thread detection device for oil drill pipes based on high-frequency eddy current is used to comprehensively detect the thread defects of the external and internal threads of the drill pipe, and has high detection accuracy; it specifically includes: External thread scanning device 2 for drill pipe, internal thread scanning device 3 for drill pipe, high-frequency eddy current probe 4 and detection system; Among them, a plurality of high-frequency eddy current probes 4 are arranged on both the external thread scanning device 2 for drill pipe and the internal thread scanning device 3 for drill pipe, and the plurality of high-frequency eddy current probes 4 are respectively electrically connected to the detection system; the external thread scanning device 2 for drill pipe is installed on the external thread of the drill pipe 1 and is used to scan the external thread defects of the drill pipe 1; the internal thread scanning device 3 for drill pipe is installed on the internal thread of the drill pipe 1 and is used to scan the internal thread defects of the drill pipe 1.

[0033] The structure of the external thread scanning device 2 for drill pipe is specifically as follows: As Figure 2As shown, the external thread scanning device 2 of the drill pipe includes a first skeleton ring 21, an external thread detection component 22, and an external thread fixing component 23; the external thread detection component 22 and the external thread fixing component 23 are movably arranged on the first skeleton ring 21; the external thread detection component 22 and the external thread fixing component 23 are respectively clamped on both sides of the external thread of the drill pipe 1; several high-frequency eddy current probes 4 are arranged on the external thread detection component 22. When scanning the defects of the external thread of the drill pipe 1, the external thread detection component 22 and the external thread fixing component 23 in the external thread scanning device 2 of the drill pipe are respectively clamped on both sides of the external thread of the drill pipe 1, and the high-frequency eddy current probes 4 on the external thread detection component 22 are used to comprehensively scan the defects of the external thread of the drill pipe 1.

[0034] As Figure 3 shown, the external thread detection component 22 includes a detection block fixing frame 221, an external thread detection block 222, and a first slider 223. The detection block fixing frame 221 is fixed inside the first skeleton ring 21; the external thread detection block 222 is installed on the detection block fixing frame 221. Threads are tapped on the side of the external thread detection block 222 close to the external thread of the drill pipe 1, and high-frequency eddy current probes 4 are installed on the threads of the external thread detection block 222, as Figure 4 shown.

[0035] As Figure 3 shown, the external thread fixing component 23 includes a lifting adjustment cylinder 231, an external thread support block 232, a first slide rail 233, and an adjustment rod 234; the lifting adjustment cylinder 231 is movably connected inside the first skeleton ring 21; the top of the external thread support block 232 is inserted into the lifting adjustment cylinder 231, and the bolt on the side wall of the lifting adjustment cylinder 231 fixes the external thread support block 232. The external thread support block 232 can be axially adjusted up and down relative to the lifting adjustment cylinder 231, and its position can be flexibly adjusted and fixed when installing the external thread support block 232; threads are tapped on the side of the external thread support block 232 close to the external thread of the drill pipe 1.

[0036] When detecting the external thread of the drill pipe 1, the threaded sides of the external thread detection block 222 and the external thread support block 232 are respectively connected to both sides of the external thread of the drill pipe 1. During the detection process, the first skeleton ring 21 is rotated, and the first skeleton ring 21 drives the two to move along the external thread of the drill pipe 1, thereby comprehensively scanning the external thread of the drill pipe 1.

[0037] One side of the detection block fixing frame 221 close to the lifting adjustment cylinder 231 is connected with a first slider 223, and one side of the lifting adjustment cylinder 231 close to the detection block fixing frame 221 is connected with a first slide rail 233. The first slider 223 is slidably connected to the first slide rail 233; One side of the lifting and adjusting cylinder 231 away from the detection block fixing frame 221 is connected with an adjusting rod 234. The adjusting rod 234 is movably arranged in the chute of the first skeleton ring 21 and is connected with the chute through bolts. Elastic band fixing ports 24 are arranged on both the detection block fixing frame 221 and the external thread support block 232, and an elastic band is connected between the two elastic band fixing ports 24. Since the position of the external thread of the drill pipe 1 is conical, the distance between the external thread detection block 222 and the external thread support block 232 needs to be adjusted radially during each scanning process. During scanning, the external thread support block 232 moves radially under the pulling force of the elastic band, so that the external thread detection block 222 always fits with the external thread of the drill pipe 1. The design of the first slider 223 and the first slide rail 233 can ensure the accuracy and stability of the radial movement.

[0038] A circuit board accommodating groove is formed on the external thread detection block 222, and a circuit board cover 224 is installed on the circuit board accommodating groove through screws. A wire routing groove is formed on one side of the circuit board accommodating groove, and a cable buckling cover 225 is installed on the wire routing groove through screws. The circuit board accommodating groove in the external thread detection block 222 is used to accommodate the probe circuit board of the high-frequency eddy current probe 4 in the external thread detection block 222, and the circuit board cover 224 encapsulates the probe circuit board. The cable for connecting the probe circuit board passes through the wire routing groove, and the cable buckling cover 225 can fix the cable to prevent the connection position between the cable and the probe circuit board from being damaged due to pulling when the external thread detection block 222 rotates.

[0039] The specific structure of the drill pipe internal thread scanning device 3 is as follows: As Figure 5 shown, the drill pipe internal thread scanning device 3 includes a second skeleton ring 31, an internal thread detection component 32 and an internal thread fixing component 33. The internal thread detection component 32 and the internal thread fixing component 33 are movably arranged on the second skeleton ring 31. The internal thread detection component 32 and the internal thread fixing component 33 respectively abut against both sides of the internal thread of the drill pipe 1. A plurality of high-frequency eddy current probes 4 are arranged on the internal thread detection component 32. When scanning the defects of the internal thread of the drill pipe 1, the internal thread detection component 32 and the internal thread fixing component 33 respectively support on both sides of the internal thread of the drill pipe 1, and the high-frequency eddy current probes 4 on the internal thread detection component 32 perform a comprehensive scan on the internal thread of the drill pipe 1, with high scanning accuracy and fast speed.

[0040] The internal thread detection component 32 includes a detection block fixing block 321, an internal thread detection block 322 and a second slide rail 323. The detection block fixing block 321 is movably connected to the second skeleton ring 31. The internal thread detection block 322 is installed on the detection block fixing block 321, and threads are tapped on the side of the internal thread detection block 322 close to the internal thread of the drill pipe 1. High-frequency eddy current probes 4 are installed on the threads of the internal thread detection block 322, as Figure 7 shown.

[0041] The internal thread fixing assembly 33 includes an adjusting frame 331, an internal thread support block 332, and a second slider 333; the adjusting frame 331 is connected to the second skeleton ring 31; the bottom of the adjusting frame 331 is connected with an internal thread support block 332, and the side of the internal thread support block 332 close to the internal thread of the drill pipe 1 is tapped with threads. The internal thread detection block 322 and the internal thread support block 332 respectively support on both sides of the internal thread of the drill pipe 1. During detection, rotating the second skeleton ring 31 drives the two to rotate, and during the rotation, the high-frequency eddy current probe 4 on the internal thread detection block 322 detects the internal thread of the drill pipe 1.

[0042] One side of the detection block fixing block 321 close to the adjusting frame 331 is connected with a second slide rail 323, and one side of the adjusting frame 331 close to the detection block fixing block 321 is connected with a second slider 333; the second slider 333 is slidably connected to the second slide rail 323; a spring 34 is arranged between the detection block fixing block 321 and the internal thread support block 332; the spring 34 drives the detection block fixing block 321 to move radially along the direction of the second slide rail 323 through elastic force, so that the internal thread detection block 322 is attached to the internal thread of the drill pipe 1 to be measured.

[0043] The top of the second slider 333 is connected to the second skeleton ring 31 through a rod.

[0044] As Figure 6 shown, similar to the external thread detection block 222, a circuit board accommodation groove is also opened inside the internal thread detection block 322, and a circuit board cover 224 is installed on the circuit board accommodation groove through screws; a wiring groove is opened on one side of the circuit board accommodation groove, and a cable buckling cover 225 is installed on the wiring groove through screws. The circuit board accommodation groove in the internal thread detection block 322 is used to accommodate the probe circuit board of the high-frequency eddy current probe 4 in the internal thread detection block 322.

[0045] Rubber rings 25 are wrapped on both the first skeleton ring 21 and the second skeleton ring 31, and the rubber rings 25 play a role in protecting the hands.

[0046] The specific structure of the high-frequency eddy current probe 4 is: As Figure 8 shown, the high-frequency eddy current probe 4 includes two copper coils 42 and two ferrites 41. The two copper coils 42 are arranged side by side, and the two ferrites 41 are respectively fixed inside the two copper coils 42; the two copper coils 42 are connected to the detection system through a bridge-type adjustment circuit.

[0047] Two copper coils 42 are connected to a bridge-type conditioning circuit. When there is a defect at the bottom of one of the coils, the impedance of the coil changes, breaking the balance of the bridge, and thus a response output can be generated for the detected defect. The high-frequency eddy current probe 4 composed of the copper coil 42 and the ferrite 41 has higher spatial resolution; the ferrite 41 has high magnetic permeability, which can converge the magnetic induction lines generated by the copper coil 42 to enhance the magnetic field generated by the copper coil 42 and improve the eddy current detection sensitivity; the inductance of the copper coil 42 is between 0.1 - 50 uH, the resistance is between 0.1 - 10 Ω, the L∶R ratio is high, and the excitation signal frequency range is between 100 kHz - 3 MHz.

[0048] The specific structure of the detection system is as follows: As Figure 9 shown, the detection system includes a probe circuit board, an eddy current detection circuit board 5, a host computer 7, and a power supply 6; the probe circuit board is connected to the copper coil 42 of the high-frequency eddy current probe 4 through a bridge-type adjustment circuit; the eddy current detection circuit board 5 is electrically connected to the probe circuit board, and the host computer 7 is electrically connected to the eddy current detection circuit board 5; the power supply 6 is connected to the eddy current detection circuit board 5 to supply power to the eddy current detection circuit board 5.

[0049] The probe circuit board is arranged in the circuit board accommodation groove of the external thread detection block 222 or the internal thread detection block 322 and is connected to the high-frequency eddy current probe 4 inside it respectively, and 16 high-frequency eddy current probes 4 can be connected simultaneously.

[0050] As Figure 10 shown, the eddy current detection circuit board 5 includes a preamplifier circuit, a system-on-chip (SOC) circuit, and an alarm unit connected in sequence; the preamplifier circuit is electrically connected to the probe circuit board, and the system-on-chip circuit is electrically connected to the host computer 7.

[0051] The preamplifier circuit includes a channel switching module, an excitation signal processing circuit, and an eddy current signal processing circuit. The channel switching module is electrically connected to the probe circuit board. The channel switching module can be switched to different channels according to the channel switching signal to control the high-frequency eddy current probe 4 at different positions for defect detection, and transmit the induction signal to the preamplifier circuit through a cable. The excitation signal processing circuit and the eddy current signal processing circuit are respectively used to process the excitation signal and the eddy current signal. The excitation signal is generated by a direct digital synthesis (DDS) module, amplified by the excitation signal processing circuit, and the DDS signal is converted into an analog signal through a DAC module. The amplitude of the output signal can be adjusted by adjusting the reference voltage of the DAC module through a specific chip. The eddy current signal processing circuit is responsible for processing the differential eddy current signal after the bridge change, amplifying and performing analog-to-digital conversion and sending it to the system-on-chip circuit.

[0052] The system - on - chip circuit includes a direct digital frequency synthesis module (DDS module), a phase - sensitive detection module, a control unit, a serial port module, and an Ethernet communication module. The DDS module can generate digital signals with arbitrary frequencies and arbitrary waveforms such as sine waves, square waves, triangular waves, and sawtooth waves. The phase - sensitive detection module multiplies the voltage signal collected by the ADC module with the output signal of the original DDS module and the phase - shifted signal for phase - locked amplification, obtaining the real and imaginary parts of the induction signal, and finally parsing to obtain the required impedance change signal.

[0053] The serial port module and the Ethernet communication module are responsible for the signal transmission between the host computer 7 and the system - on - chip circuit. The control unit is responsible for data parsing and data packaging for upward transmission, generating channel switching signals and controlling the alarm unit to alarm.

[0054] The host computer 7 is designed based on object - oriented language programming. It includes a UDP module, a serial port module, a database, an excitation signal control module, and a multi - channel signal display module. The UDP module and the serial communication module send information such as the excitation signal frequency, amplitude, gain, and channels set by the host computer 7 to the eddy current detection circuit board 5. The database module is used to save multi - channel signals for thread defect analysis. The excitation signal control module generates control signals such as the excitation signal waveform, frequency, amplitude, and gain. The multi - channel signal display module visually displays the real and imaginary parts of the impedance in the form of a time - base diagram and an impedance diagram, facilitating the user to observe the scanning results in real - time.

[0055] In this embodiment, ZYNQ with the model number XC7Z020 is selected as the system - on - chip circuit.

[0056] In this embodiment, the alarm unit uses a buzzer or a warning light.

[0057] In this embodiment, the host computer 7 is preferably a computer.

[0058] Embodiment 2 Based on the high - frequency eddy current - based oil drill pipe thread detection device provided in Embodiment 1, this embodiment provides a high - frequency eddy current - based oil drill pipe thread detection method for detecting external thread defects of the drill pipe 1, which specifically includes the following steps: Step 1: Connect the probe circuit board and the eddy current detection circuit board 5; connect the eddy current detection circuit board 5 to the host computer 7 through a network cable and a data cable, input the IP address and port number of the device in the host computer 7, set the COM port and baud rate, and open the corresponding serial port.

[0059] Step 2: Install the drill pipe external thread scanning device 2 on the drill pipe 1; the specific operation is as follows: Place the external thread detection block 222 and the external thread support block 232 on both sides of the external thread of the drill pipe 1, and first fit the threaded side of the external thread detection block 222 to the external thread of the drill pipe 1; then loosen the bolts on the lifting adjustment cylinder 231, and make axial fine adjustment on the external thread support block 232. After adjustment, fit the threaded side of the external thread support block 232 to the external thread of the drill pipe 1, and make the threads of the two match; Connect the rubber band fixing opening 24 on the detection block fixing frame 221 and the rubber band fixing opening 24 on the external thread support block 232 through a rubber band; The external thread detection block 222 and the external thread support block 232 are driven to rotate by the first skeleton ring 21, so that the high-frequency eddy current probe 4 on the external thread detection block 222 is aligned with the thread position without defects on the drill pipe, and this position is used as the initial position for detection.

[0060] Step 3: Set the alarm threshold of the alarm unit and the parameters of the high-frequency eddy current probe 4, such as waveform, frequency, gain, drive and other information, in the host computer 7, and send this information to the system-level chip circuit; when the high-frequency eddy current probe 4 is aligned with the thread position without defects on the drill rod 1, click to set the balance center.

[0061] Step 4: Start the detection program, manually drive the drill pipe external thread scanning device 2 to rotate, and start scanning. During the scanning process, the distance between the external thread detection block 222 and the external thread support block 232 increases or shrinks to adapt to the tapered structure of the external thread of the drill pipe 1. Under the tension of the rubber band, the external thread detection block 222 and the external thread support block 232 can always be tightly attached to both sides of the external thread of the drill pipe 1; When the high-frequency eddy current probe 4 detects a defect signal, the system-level chip circuit controls the alarm unit to sound an alarm.

[0062] Step 5: Repeat the scan multiple times to verify the test results and accurately determine the defect location.

[0063] Step 6: After the detection is completed, remove the rubber band; pull the external thread detection block 222 and the external thread support block 232 to both sides to make them detach from the external thread of the drill pipe 1 and then remove them to avoid collision with the external thread of the drill pipe 1 and thus damage to the drill pipe 1; finally, the host computer 7 exports the detection data and performs scanning data processing, and the detection is completed.

[0064] Example 3 This embodiment provides a method for detecting oil drill pipe threads based on high-frequency eddy currents based on the oil drill pipe thread detection device provided in Embodiment 1, which is used to detect internal thread defects of a drill pipe 1, and specifically includes the following steps: Step 1: Connect the probe circuit board and the eddy current detection circuit board 5; Step 2: Install the drill pipe internal thread scanning device 3 on the drill pipe 1; the specific operation is: Press the spring 34 between the internal thread detection block 322 and the internal thread support block 332, and insert the internal thread detection block 322 and the internal thread support block 332 into the inside of the drill pipe 1; Make the threads of the internal thread detection block 322 and the internal thread support block 332 fit on both sides of the internal thread of the drill pipe 1; Drive the internal thread detection block 322 and the internal thread support block 332 to rotate through the second skeleton ring 31, so that the high-frequency eddy current probe 4 on the internal thread detection block 322 is aligned with the thread position on the drill pipe without defects, and this position is used as the initial position for detection.

[0065] Step 3: Set the alarm threshold of the alarm unit and the parameters of the high-frequency eddy current probe 4, such as waveform, frequency, gain, drive and other information in the host computer 7, and send this information to the system-level chip circuit; click to set the balance center after the high-frequency eddy current probe 4 is aligned with the thread position on the drill pipe 1 without defects.

[0066] Step 4: Start the detection program, manually drive the internal thread scanning device 3 of the drill pipe to rotate, and start scanning. During the scanning process, the distance between the internal thread detection block 322 and the internal thread support block 332 adapts to the conical structure of the internal thread of the drill pipe 1 and increases or contracts. Under the support of the spring 34, the internal thread detection block 322 and the internal thread support block 332 can always be close to the inner wall of the internal thread of the drill pipe 1; When the high-frequency eddy current probe 4 detects a defect signal, the system-level chip circuit controls the alarm unit to alarm.

[0067] Step 5: Repeat the scanning multiple times to verify the detection result and accurately determine the defect position.

[0068] Step 6: After the detection is completed, make the internal thread detection block 322 and the internal thread support block 332 squeeze the spring 34 towards the middle. After the threads of the internal thread detection block 322 and the internal thread support block 332 are completely separated from the internal thread of the drill pipe 1, then take out the internal thread scanning device 3 of the drill pipe; finally, export the detection data by the host computer 7 and perform scanning data processing.

[0069] Those of ordinary skill in the art will realize that the embodiments here are to help the reader understand the principles of the present invention and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations without departing from the essence of the present invention according to the technical revelations disclosed in the present invention, and these deformations and combinations are still within the protection scope of the invention.

Claims

1. A petroleum drill pipe thread detection device based on high-frequency eddy current, characterized in that: The invention comprises a drill rod external thread scanning device (2) and a drill rod internal thread scanning device (3); the drill rod external thread scanning device (2) and the drill rod internal thread scanning device (3) are both provided with a plurality of high-frequency eddy current probes (4), and the plurality of high-frequency eddy current probes (4) are respectively electrically connected to a detection system; the drill rod external thread scanning device (2) is installed on the external thread of the drill rod (1) and is used to scan the external thread defects of the drill rod (1); the drill rod internal thread scanning device (3) is installed on the internal thread of the drill rod (1) and is used to scan the internal thread defects of the drill rod (1).

2. The oil drill pipe thread detection device based on high-frequency eddy current according to claim 1 is characterized in that: The drill rod external thread scanning device (2) comprises a first skeleton ring (21), on which an external thread detection component (22) and an external thread fixing component (23) are movably arranged; the external thread detection component (22) and the external thread fixing component (23) are respectively clamped on two sides of the external thread of the drill rod (1); The drill rod internal thread scanning device (3) comprises a second skeleton ring (31), on which an internal thread detection component (32) and an internal thread fixing component (33) are movably arranged; the internal thread detection component (32) and the internal thread fixing component (33) are respectively abutted against two sides of the internal thread of the drill rod (1); The high-frequency eddy current probe (4) is arranged on the external thread detection component (22) and the internal thread detection component (32).

3. The oil drill pipe thread detection device based on high-frequency eddy current according to claim 2 is characterized in that: The external thread detection assembly (22) comprises a detection block fixing frame (221), the detection block fixing frame (221) being fixed on the inner side of the first skeleton ring (21); an external thread detection block (222) is mounted on the detection block fixing frame (221), a side of the external thread detection block (222) close to the external thread of the drill rod (1) is threaded, and the high-frequency eddy current probe (4) is mounted on the thread of the external thread detection block (222); The external thread fixing assembly (23) comprises a lifting adjustment cylinder (231) and an external thread support block (232); the lifting adjustment cylinder (231) is movably connected to the inner side of the first skeleton ring (21); the top of the external thread support block (232) is inserted into the lifting adjustment cylinder (231), and bolts on the side wall of the lifting adjustment cylinder (231) fix the external thread support block (232); and a thread is tapped on a side of the external thread support block (232) close to the external thread of the drill rod (1).

4. The oil drill pipe thread detection device based on high-frequency eddy current according to claim 3 is characterized in that: A first sliding block (223) is connected to a side of the detection block fixing frame (221) close to the lifting adjustment cylinder (231), a first sliding rail (233) is connected to a side of the lifting adjustment cylinder (231) close to the detection block fixing frame (221), and the first sliding block (223) is slidably connected to the first sliding rail (233); An adjustment rod (234) is connected to a side of the lifting adjustment cylinder (231) away from the detection block fixing frame (221); the adjustment rod (234) is movably arranged in a slide groove of the first skeleton ring (21) and connected to the slide groove via a bolt; The detection block fixing frame (221) and the external thread support block (232) are both provided with a rubber band fixing opening (24), and a rubber band is connected between the two rubber band fixing openings (24).

5. The oil drill pipe thread detection device based on high-frequency eddy current according to claim 3 is characterized in that: The external thread detection block (222) is provided with a circuit board receiving groove, on which a circuit board cover (224) is mounted by screws; a wiring groove is provided on one side of the circuit board receiving groove, on which a cable buckle cover (225) is mounted by screws.

6. The oil drill pipe thread detection device based on high-frequency eddy current according to claim 2 is characterized in that: The internal thread detection assembly (32) comprises a detection block fixing block (321), the detection block fixing block (321) being movably connected to the second skeleton ring (31); an internal thread detection block (322) is mounted on the detection block fixing block (321), and a side of the internal thread detection block (322) close to the internal thread of the drill rod (1) is tapped with a thread; the high-frequency eddy current probe (4) is mounted on the thread of the internal thread detection block (322); The internal thread fixing assembly (33) comprises an adjustment frame (331), the adjustment frame (331) being connected to the second skeleton ring (31); an internal thread support block (332) is connected to the bottom of the adjustment frame (331), and a thread is tapped on a side of the internal thread of the drill rod (1) close to the internal thread of the drill rod (1).

7. The oil drill pipe thread detection device based on high-frequency eddy current according to claim 6 is characterized in that: A second slide rail (323) is connected to one side of the detection block fixing block (321) close to the adjustment frame (331), and a second slider (333) is connected to one side of the adjustment frame (331) close to the detection block fixing block (321); the second slider (333) is slidably connected to the second slide rail (323); a spring (34) is provided between the detection block fixing block (321) and the internal thread support block (332); The top of the second sliding block (333) is connected to the second skeleton ring (31) via a rod.

8. The oil drill pipe thread detection device based on high-frequency eddy current according to claim 2 is characterized in that: The high-frequency eddy current probe (4) comprises two copper coils (42) arranged side by side, two ferrites (41) being fixed inside the two copper coils (42) respectively; the two copper coils (42) are connected to the detection system via a bridge adjustment circuit.

9. The oil drill pipe thread detection device based on high-frequency eddy current according to claim 8 is characterized in that: The detection system comprises a probe circuit board, an eddy current detection circuit board (5) and a host computer (7); the probe circuit board is connected to the copper coil (42) of the high-frequency eddy current probe (4) via a bridge adjustment circuit; the eddy current detection circuit board (5) is electrically connected to the probe circuit board, and the host computer (7) is electrically connected to the eddy current detection circuit board (5); The eddy current detection circuit board (5) comprises a front-end circuit, a system-on-chip circuit and an alarm unit which are connected in sequence; the front-end circuit is electrically connected to the probe circuit board, and the system-on-chip circuit is electrically connected to the host computer (7).

10. A detection method for a petroleum drill pipe thread detection device based on high-frequency eddy current according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Connect the probe circuit board and the eddy current detection circuit board (5); Step 2: Installing a drill rod external thread scanning device (2) or a drill rod internal thread scanning device (3) on the drill rod (1); Step 3: setting the alarm threshold of the alarm unit and the parameters of the high-frequency eddy current probe (4) in the host computer (7); aligning the high-frequency eddy current probe (4) with a thread position without defects on the drill rod (1) and clicking Set Balance Center; Step 4: Start the detection program, turn the drill pipe external thread scanning device (2) or the drill pipe internal thread scanning device (3) to start scanning, and when the high-frequency eddy current probe (4) detects a defect signal, the system-level chip circuit controls the alarm unit to alarm; Step 5: After the scanning is completed, the drill pipe external thread scanning device (2) or the drill pipe internal thread scanning device (3) is removed, and the host computer (7) exports the detection data and performs scanning data processing, and the detection is completed.

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