A method and system for detecting defects in a valve stem of a gas tree in service

Abstract

The application discloses a kind of in-service gas tree valve stem defect detection method and system, it is related to ultrasonic testing technical field, comprising the following steps: making valve stem simulation test piece with defect characteristics and comparative test piece without defect characteristics;In the comparative test piece is scanned by ultrasonic phased array, and the standard echo parameter contrast table of comparative test piece disassembly state is obtained;The comparative test piece is installed in the inside of gas tree wellhead valve, and is scanned again by ultrasonic phased array, and the standard echo parameter contrast table of comparative test piece is obtained under the condition of not disassembly;Make echo feature contrast chart;The valve stem simulation test piece is installed in the inside of gas tree wellhead valve, and is scanned by ultrasonic phased array, and the structure characteristic waveform chart of valve stem simulation test piece is obtained, and the structure characteristic waveform chart and the echo feature contrast chart are compared and analyzed.The application can realize that, without disassembly valve, corrosion defect on the surface of valve stem in the inside of valve is realized online detection.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic testing technology, specifically to a method and system for detecting defects in the valve stem of an in-service gas production tree. Background Technology

[0002] The wellhead tree (or production tree) is a wellhead device used in natural gas extraction surface processes for operations such as well shut-in, pressure and gas volume regulation, and circulating well control. It connects the gas well oil, casing, and surface process equipment, and is one of the core pieces of equipment in natural gas extraction. During operation, it has been found that even small amounts of corrosive media entering the upper area of ​​the production tree valves have caused significant localized corrosion in areas that are theoretically not in contact with the corrosive media, such as the valve stem. This severely affects the valve's service performance and reliability. Therefore, regular inspection and evaluation of corrosion on the valve stem inside the production tree valves, especially without affecting production and without disassembly, has significant engineering application value.

[0003] Without disassembly, the inlet and outlet channels and flange faces of wellhead valves, being external to the overall structure, can typically be detected for corrosion defects using phased array detection technology. Furthermore, due to the substantial thickness of the valve body and valve plate, corrosion damage generally does not cause valve failure. However, for the need to inspect the valve stem internally, limitations exist due to the valve stem's location within the valve, the complex internal structure, and the significant thickness of the valve body. Currently, effective technology for inspecting the valve stem without disassembly is lacking. Therefore, current methods for valve stem inspection involve returning the wellhead valve to the field for disassembly and inspection. This not only impacts the normal production efficiency of oil and gas fields, but also involves long cycles and high costs. Moreover, it fails to address the inherent safety aspects of online inspection and evaluation of in-service wellhead equipment. Therefore, conducting online inspection of the valve stems internally in in-service wellhead valves is of paramount engineering significance for eliminating safety hazards caused by internal valve stem defects and ensuring the safety of gas well production. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention aims to provide a method and system for detecting defects in the valve stem of an in-service gas production tree, enabling online detection of corrosion defects on the surface of the valve stem inside the valve without disassembling the valve.

[0005] This invention is achieved through the following technical solution:

[0006] A method for detecting defects in the valve stem of an in-service gas production tree includes the following steps:

[0007] Step 1: Prepare a valve stem simulation specimen with defect characteristics and a control specimen without defect characteristics;

[0008] Step 2: Perform ultrasonic phased array scanning on the comparison specimen to obtain the structural echo characteristics of the comparison specimen. Based on the structural echo characteristics, obtain a standard echo parameter comparison table of the comparison specimen in the disassembled state.

[0009] Step 3: Insert the comparative specimen into the wellhead valve of the gas production tree and perform ultrasonic phased array scanning again to obtain a standard echo parameter comparison table of the comparative specimen without disassembly; based on the standard echo parameter comparison table of the comparative specimen with disassembly and the standard echo parameter comparison table of the comparative specimen without disassembly, make an echo feature comparison chart.

[0010] Step 4: The valve stem simulation specimen is installed inside the wellhead valve of the gas production tree and ultrasonic phased array scanning is performed to obtain the structural feature waveform diagram of the valve stem simulation specimen. The structural feature waveform diagram and the echo feature comparison diagram are then compared and analyzed.

[0011] Compared to existing technologies that currently require wellhead valves to be returned to the field and disassembled for inspection, which not only affects the normal production efficiency of oil and gas fields, but also involves long cycles and high costs, and fails to address the issue of online inspection and evaluation of in-service wellhead equipment from an inherent safety perspective, this invention provides a method for detecting defects in in-service gas production tree valve stems. This method can directly detect corrosion defects hidden inside the valve stem without disassembling the valve stem inside the in-service valve. Specifically, the method first involves fabricating a corresponding valve stem simulation specimen based on the defect characteristics of the valve stem inside the gas production tree wellhead valve. Artificial groove-shaped defects are etched at the valve stem end and the minor diameter of the thread, which are prone to corrosion. Simultaneously, a valve stem comparison specimen is fabricated to obtain characteristic waveforms under standard defect-free conditions. The comparison specimen is the valve stem specimen without the artificial groove-shaped defects. The comparison specimen is then subjected to ultrasonic phased array scanning. An ultrasonic phased array device emits an ultrasonic beam, with the end of the specimen serving as the emission position of the ultrasonic phased array probe. The structural echo characteristics of the comparison specimen are obtained, and a standard echo parameter comparison table is created based on these characteristics of the specimen under disassembled valve stem conditions. A comparison specimen, i.e., a defect-free valve stem specimen, was installed inside the wellhead valve of the gas production tree and filled with sealing grease. Using an ultrasonic phased array testing device, an ultrasonic beam was emitted from the exposed end of the valve stem during assembly, obtaining a standard echo parameter comparison table for the non-disassembly state. The standard echo parameter characteristic comparison tables for the disassembly and non-disassembly states were then compiled into a feature comparison diagram simultaneously containing both states. Finally, a defect simulation specimen was installed into the wellhead valve of the gas production tree, and an ultrasonic phased array device was used to scan the exposed end of the defect simulation specimen, obtaining waveform diagrams of artificial defects and valve stem structural characteristics. The detected waveform diagram of the defect specimen was compared and analyzed with the standard echo parameter comparison diagram; any discrepancies identified were potential defects.

[0012] The above solutions aim to achieve the following: online detection of corrosion defects on the surface of the valve stem inside the valve without disassembling the valve; and ensure that valve stem defect detection is carried out while the gas-producing tree valve is in normal service, without affecting normal production efficiency, thereby eliminating safety hazards and reducing economic losses.

[0013] A further proposed solution is that the defect feature is a groove-shaped defect.

[0014] A further proposed approach includes the following steps in the ultrasonic phased array scanning:

[0015] Adjust the position and orientation of the ultrasonic probe in the ultrasonic phased array testing equipment to ensure that the ultrasonic probe and the valve stem end are concentric;

[0016] Then, the ultrasonic phased array testing equipment is turned on, the center frequency and number of crystals of the corresponding ultrasonic probe are set, and the ultrasonic signal is excited by the ultrasonic transducer to perform ultrasonic probe rotation scanning.

[0017] A further step in the rotating scan includes the following steps:

[0018] In the ultrasonic phased array detection device, the deflection angle is set by adjusting the focusing law, the focusing law of each crystal module around the end of the ultrasonic probe is adjusted in sequence, and the probe is excited in sequence.

[0019] After being controlled by the focusing law, the ultrasonic beam is deflected toward the valve stem surface. The deflection angle of each crystal module is controlled by the ultrasonic phased array detection equipment. The angle is scanned from small to large to obtain the structural information of the circumferential surface of the valve stem.

[0020] Input the actual depth of the specimen into the ultrasonic phased array instrument to obtain the propagation time required for the bottom wave signal echo of a single excitation;

[0021] The intermittent working time of each chip module is set to the total time from the excitation of the ultrasonic beam to the single reception of the bottom wave signal. Several chip modules are excited in sequence to obtain the single scan result.

[0022] Next, the ultrasonic probe is rotated at a certain angle and scanned several times to cover the entire circumferential surface of the valve stem. The above steps are repeated for each scan. When the ultrasonic probe is rotated at a certain angle, the center of the ultrasonic probe does not deviate from the center of the valve stem, and the vertical distance between the ultrasonic probe and the valve stem remains unchanged.

[0023] In a further embodiment, a gap for injecting coupling agent is left between the end of the ultrasonic probe and the end of the valve stem.

[0024] A further step is to calibrate the sound velocity of the phased array probe before performing ultrasonic phased array scanning on the comparative specimen.

[0025] A further solution is an in-service gas production tree valve stem defect detection system, including an ultrasonic probe;

[0026] The ultrasonic probe includes a probe body, a rotation positioning auxiliary tooling, and a wafer module. Several wafer modules are detachably distributed around the end of the probe body. The wafer modules are connected to the communication part of the probe body and are used to excite the ultrasonic phased array.

[0027] The rotary positioning auxiliary fixture is located at the center of the end of the probe body. The lower end of the rotary positioning auxiliary fixture is connected to the end of the valve stem, and the upper end of the rotary positioning auxiliary fixture is rotatably connected to the probe body. The probe body can rotate around its own axis.

[0028] In a further embodiment, the probe body has several ports evenly distributed around its circumference, each port having a slot, and the slot is connected to the communication part inside the probe body via a communication cable.

[0029] The chip module includes a module housing, the upper end of which is used to insert into the socket, and the upper end of the module housing has a plug that is compatible with the slot on the side facing the socket.

[0030] The lower end of the module housing has several bottom chips arranged radially along the probe body, and the bottom chips are connected to the communication part inside the probe body through the slot.

[0031] In a further embodiment, the socket is a T-type socket, and the upper part of the module housing is a T-type plug that is compatible with the T-type socket.

[0032] In a further embodiment, the rotary positioning auxiliary tooling includes a positioning support column, the bottom of which has a suction cup, and a bearing is rotatably sleeved on the positioning support column.

[0033] The probe body has a through hole on its axis, the upper end of which is used to install and insert the communication part; the lower end of which has a bearing mounting hole for installing the bearing; and the bottom of the communication part has a round hole that positions with the upper end of the positioning support.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] This invention provides a method and system for detecting defects in the valve stem of an in-service gas production tree. It can detect corrosion defects on the surface of the valve stem inside the valve online without disassembling the valve. It can also ensure that valve stem defects are detected while the gas production tree valve is in normal service and without affecting normal production efficiency, thereby eliminating safety hazards and reducing economic losses. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0037] Figure 1 This is an assembly drawing of an ultrasonic probe according to an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of the structure of an ultrasonic body according to an embodiment of the present invention;

[0039] Figure 3 An internal cross-sectional view of an ultrasonic body according to an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of the structure of a chip module according to an embodiment of the present invention;

[0041] Figure 5 A bottom schematic diagram of a wafer module according to an embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram of the structure of a rotary positioning auxiliary tooling according to an embodiment of the present invention;

[0043] Figure 7 A schematic diagram of the communication section of one embodiment of the present invention is provided;

[0044] Figure 8 This is a schematic diagram simulating the operation of the valve stem probe inside the wellhead valve of the gas production tree according to an embodiment of the present invention;

[0045] Figure 9 A schematic diagram of the valve stem according to an embodiment of the present invention.

[0046] The attached diagram shows the markings and corresponding component names:

[0047] 1-Ultrasonic probe, 11-Probe body, 12-Slot, 13-Groove, 14-Bearing mounting hole, 16-Communication cable, 2-Chip module, 22-Plug, 23-Module housing, 24-Plug-in board, 25-Bottom chip, 3-Rotation positioning auxiliary tooling, 31-Positioning support, 32-Suction cup, 33-Boss, 34-Bearing, 41-Main cable, 42-Communication section, 43-Communication head, 5-Valve stem. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0049] Example 1:

[0050] This embodiment 1 provides a method for detecting defects in the valve stem of an in-service gas production tree, including the following specific steps:

[0051] Select appropriate probes and ultrasonic phased array testing instruments.

[0052] Step 1: Based on the defect characteristics of the valve stem inside the wellhead valve, fabricate corresponding simulated valve stem specimens. Artificial groove defects are etched at the valve stem end, which is prone to corrosion, and at the minor diameter of the thread. Simultaneously, fabricate comparative valve stem specimens. These comparative specimens are used to obtain characteristic waveform diagrams under standard defect-free conditions; the comparative specimens are valve stem specimens without artificial groove defects.

[0053] In step one, the artificial defect simulation specimen has a groove-shaped defect. The defect size parameters of two defects in the same specimen are the same, as shown in the table below:

[0054] Defect area Length (mm) Width (mm) Depth (mm) Distance from end (mm) end 10 0.5 2 160 end 10 0.5 2 180 end 10 0.5 2 200

[0055] Step 2: Perform ultrasonic phased array scanning on the comparison specimen. Use an ultrasonic phased array device to emit an ultrasonic beam. Use the end of the specimen as the emission position of the ultrasonic phased array probe to obtain the structural echo characteristics of the comparison specimen. Based on the structural echo characteristics of the specimen, make a standard echo parameter comparison table of valve stem 5 in disassembled state.

[0056] The specific method for ultrasonic scanning in step two is as follows: First, select a suitable ultrasonic phased array testing device and choose a 64-chip specially designed ultrasonic phased array probe. Adjust the device scanning mode to S-shaped scanning. Adjust the ultrasonic probe 1 position and ensure that the probe is concentric with the end of valve stem 5. The center position of the probe is 0.5mm away from the end of valve stem 5, leaving space for coupling agent filling. Perform rotational scanning with the help of auxiliary fixtures. The auxiliary fixtures ensure that the center of the probe does not deviate from the center of valve stem 5 during rotational scanning, and at the same time ensure that the vertical distance between the probe and valve stem 5 does not change. This reduces the impact of the instability of the handheld probe on the scanning results of ultrasonic phased array technology. After setting the probe position and installing the auxiliary fixtures, turn on the ultrasonic phased array device and set the corresponding probe center frequency and number of chips. Before performing ultrasonic phased array scanning on the comparison specimen, perform phased array probe sound velocity calibration. Sound velocity calibration is an important step for ultrasonic phased array to ensure the accuracy of the detected defect depth and location.

[0057] When testing valve stem 5 using an ultrasonic phased array, an ultrasonic signal is first excited by an ultrasonic transducer. The generated ultrasonic beam propagates inside valve stem 5. When the ultrasonic beam encounters a region within valve stem 5 where the geometry has changed, a reflected echo is generated. A specialized ultrasonic probe receives the reflected echo and transmits the received data to the ultrasonic phased array testing instrument. The instrument then exports the data to create an ultrasonic phased array test pattern for the comparative specimen.

[0058] Step 3: Install the comparison specimen, i.e., the defect-free valve stem 5 specimen, into the gas production tree wellhead valve and fill it with sealing grease. Use an ultrasonic phased array testing device to emit an ultrasonic beam from the exposed end of the valve stem 5 during assembly. Obtain a comparison table of standard echo parameters in the non-disassembly state. Compile the comparison tables of standard echo parameter characteristics in the disassembly and non-disassembly states into a feature comparison chart that simultaneously includes both states.

[0059] Step 4: Install the defect simulation specimen into the wellhead valve of the gas production tree. Use an ultrasonic phased array device to scan the exposed end of the defect simulation specimen with an ultrasonic beam to obtain waveform diagrams of the artificial defects and the structural characteristics of valve stem 5. Compare and analyze the detected waveform diagram of the defect specimen with the standard echo parameter comparison diagram. The parts with differences in the analysis are the possible defects.

[0060] Example 2:

[0061] like Figures 1-9 As shown, this embodiment 2 provides a defect detection system for the in-service gas production tree valve stem 5 used in embodiment 1, such as... Figures 1-7 As shown. It includes an ultrasonic probe 1; the ultrasonic probe 1 includes a probe body 11, a rotation positioning auxiliary tooling 3 and a wafer module 2; a plurality of wafer modules 2 are detachably and evenly distributed around the end of the probe body 11, the wafer modules 2 are connected to the communication part 42 of the probe body 11 and are used to excite the ultrasonic phased array;

[0062] The rotary positioning auxiliary tooling 3 is located at the center of the end of the probe body 11. The lower end of the rotary positioning auxiliary tooling 3 is connected to the end of the valve stem 5, and the upper end of the rotary positioning auxiliary tooling 3 is rotatably connected to the probe body 11. The probe body 11 can rotate around its own axis.

[0063] In the above scheme, the ultrasonic probe 1 mainly consists of three parts: the probe body 11, the rotation positioning auxiliary fixture 3, and the detachable wafer module 2. The probe body 11 has six evenly distributed circumferential ports at its end for connecting the wafer module 2, with each port's centerline at a 60-degree angle. Each port contains 16 symmetrical slots 12, which can be used to connect detachable phased array ultrasonic wafer modules 2 of two different models: 16-wafer and 8-wafer. The number of slots 12 on the probe body 11 can also be increased to connect detachable wafer modules 2 with 32 or more wafers. When using linear scanning, detachable wafers with 32 or more wafers are selected to achieve large-area scanning. When using focusing methods for multi-angle scanning, 8-wafer or 16-wafer modules are selected to ensure sound wave superposition. The detachable wafer design allows the probe to be flexibly applied to different valve stem 5 detection scenarios. The probe body 11 has a mounting clip at slot 12 to ensure that the detachable chip will not fall off due to rotation during the inspection process. When using the ultrasonic probe 1 to inspect the valve stem 5, the ultrasonic phased array is excited by the chip module 2. The ultrasonic beam is reflected by the internal structure and defects of the valve stem 5 and then received by the chip, achieving self-emission and self-reception. The probe body has a recess on its circumference, i.e., a groove 13, for easy hand operation.

[0064] In this embodiment, to achieve detachable connection of the chip module 2, the probe body 11 has several ports evenly distributed around its end, each port having a slot 12. The slot 12 is connected to the communication part 42 inside the probe body 11 via a communication cable 16. The chip module 2 includes a module housing 23, the upper end of which is used to insert into the port. The upper end of the module housing 23 facing the port has a plug 22 that is compatible with the slot 12. The lower end of the module housing 23 has several bottom chips 25 arranged radially along the probe body 11. The several bottom chips 25 are connected to the communication part 42 inside the probe body 11 via the slot 12. In this design, the outer casing 23 of the chip module 2 resembles an L-shaped plug 22, and the socket is an L-shaped connector adapted to the L-shaped plug 22. The inner surface of the upper end of the outer casing 23 has a plug 22; inserting the plug 22 into the slot 12 establishes a communication connection. At this time, the chip module 2 and the probe communication section 42 are connected to the bottom chip 25 using different numbers of plugs 22. The ultrasonic phased array chips are located at the bottom of the outer casing 23, arranged sequentially perpendicular to the plane of symmetry. When the focusing law and other control information communicate with the module via the plug 22 from the probe body 11 cable, the bottom chip 25 excites the corresponding chip according to the received focusing law, achieving deflection and focusing of the ultrasonic beam. This allows for beam angle control, enabling scanning of the circumferential surface of the valve stem 5. The number of bottom chips 25 can range from 8 to 64, selected according to actual usage requirements. Modules with different numbers of chips have the same overall structure and the same chip spacing.

[0065] In this embodiment, to prevent the chip module 2 from swaying along the probe body 11 axis, the socket is a T-shaped socket, and the upper end of the module housing 23 is a T-shaped plug 22 that is compatible with the T-shaped socket.

[0066] In this embodiment, as a specific implementation of a rotary positioning auxiliary tooling 3, the rotary positioning auxiliary tooling 3 includes a positioning support column 31, the bottom of which has a suction cup 32, and a bearing 34 is rotatably sleeved on the positioning support column 31; the probe body 11 has a through hole on its axis, the upper end of which is used to install and insert a communication part 42; the lower end of which has a bearing mounting hole 14 for installing the bearing 34; the bottom of the communication part 42 has a circular hole that positions with the upper end of the positioning support column 31. In this solution, the bottom of the positioning support column 31 is provided with a suction cup 32 for connecting to the end of the valve stem 5 to ensure that the tooling does not move axially. The upper end of the suction cup 32 is a boss 33 fixed on the positioning support column 31. The size of the boss 33 is slightly smaller than that of the bearing 34, and it is used to abut against the inner ring of the bearing 34. The bearing 34 and the positioning support column 31 are interference-fitted, and the bottom of the bearing 34 is in direct contact with the supporting boss 33. After the probe is clamped, the auxiliary fixture contacts the probe through bearing 34. When the probe rotates, the auxiliary fixture ensures that its axial position will not shift.

[0067] Specific working principle:

[0068] First, the auxiliary fixture is connected to the center of the valve stem 5 end via suction cup 32, and then the bearing 34 is inserted. Next, a suitable number of detachable wafer modules 2 are selected based on the actual length of the valve stem 5 and connected to the probe body 11. Six detachable wafers are used for each ultrasonic phased array scan. The six detachable wafer modules 2 are connected to the probe body 11 to complete probe assembly. After the probe body 11 is assembled, it is inserted into the auxiliary fixture through the center hole. The probe body 11 has a step with the same size as the bearing 34 inside; the bearing 34 is pressed through the step hole to achieve axial positioning of the probe body 11. After installation, coupling agent is injected between the probe and the upper surface of the valve stem 5, and the main cable 41 is connected to the ultrasonic phased array probe device. The probe parameters are set in the ultrasonic phased array device, the appropriate number of wafers and scan type are selected, and the deflection angle is set by adjusting the focusing law. The focusing law of each wafer module 2 is adjusted sequentially. The phased array wafers arranged at the bottom are sequentially excited by the focusing law transmitted from the probe body 11. After being controlled by the focusing law, the ultrasonic beam is deflected towards the surface of the valve stem 5. The deflection angle of each wafer module 2 is controlled by the phased array instrument, and the scanning is performed from small to large angles to obtain the structural information of the circumferential surface of the valve stem 5. To complete one scan, six detachable wafer modules 2 need to be excited sequentially. The actual depth of the specimen is input into the ultrasonic phased array instrument to obtain the propagation time required for the bottom wave signal echo of a single excitation. The intermittent working time of each wafer module 2 is set as the total time from the excitation of the ultrasonic beam to the single reception of the bottom wave signal. The six wafer modules 2 are excited sequentially to obtain the single scan result. Then, the probe is rotated 60 degrees to perform a second scan to cover the entire circumferential surface of the valve stem 5. The second scan procedure is the same as the first scan result.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A defect detection system for in-service gas production tree valve stems, characterized in that, Including ultrasound probes; The ultrasonic probe includes a probe body (11), a rotation positioning auxiliary tooling and a wafer module; the probe body (11) has several wafer modules detachably distributed around its end in a circumferential direction, and the wafer modules are connected to the communication part of the probe body (11) and used to excite the ultrasonic phased array. The rotary positioning auxiliary tooling is located at the center of the end of the probe body (11). The lower end of the rotary positioning auxiliary tooling is connected to the end of the valve stem, and the upper end of the rotary positioning auxiliary tooling is rotatably connected to the probe body (11). The probe body (11) can rotate around its own axis. The rotary positioning auxiliary tooling includes a positioning support column (31), the bottom of which is equipped with a suction cup (32), and a bearing (34) is rotatably sleeved on the positioning support column (31). The probe body (11) has a through hole on its axis, the upper end of which is used to install the communication part; the lower end of which has a bearing mounting hole (14) for installing the bearing (34); the bottom of the communication part has a round hole that positions with the upper end of the positioning support (31). The upper end of the suction cup (32) is a boss (33) fixed on the positioning support (31). The boss (33) is used to abut against the inner ring of the bearing (34). The bearing (34) and the positioning support (31) are interference fit. The bottom of the bearing (34) is in direct contact with the boss (33). After the probe is pressed, the auxiliary tooling contacts the probe through the bearing (34).

2. The in-service gas production tree valve stem defect detection system according to claim 1, characterized in that, The probe body (11) has several ports evenly distributed around its end, and each port has a slot (12). The slot (12) is connected to the communication part inside the probe body (11) via a communication cable (16). The chip module includes a module housing (23), the upper end of which is used to insert into the socket, and the upper end of the module housing (23) facing the socket has a plug (22) that is compatible with the slot (12). The lower end of the module housing (23) has a plurality of bottom chips (25) arranged radially along the probe body (11), and the plurality of bottom chips (25) are connected to the communication part inside the probe body (11) through the slot (12).

3. The in-service gas production tree valve stem defect detection system according to claim 2, characterized in that, The socket is a T-type socket, and the upper end of the module housing (23) is a T-type plug that is compatible with the T-type socket.

4. A defect detection method for an in-service gas production tree valve stem defect detection system according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Prepare a valve stem simulation specimen with defect characteristics and a control specimen without defect characteristics; Step 2: Perform ultrasonic phased array scanning on the comparison specimen to obtain the structural echo characteristics of the comparison specimen. Based on the structural echo characteristics, obtain a standard echo parameter comparison table of the comparison specimen in the disassembled state. Step 3: Insert the comparative specimen into the wellhead valve of the gas production tree and perform ultrasonic phased array scanning again to obtain a standard echo parameter comparison table of the comparative specimen without disassembly; based on the standard echo parameter comparison table of the comparative specimen with disassembly and the standard echo parameter comparison table of the comparative specimen without disassembly, make an echo feature comparison chart. Step 4: The valve stem simulation specimen is installed inside the wellhead valve of the gas production tree and ultrasonic phased array scanning is performed to obtain the structural feature waveform diagram of the valve stem simulation specimen. The structural feature waveform diagram and the echo feature comparison diagram are then compared and analyzed.

5. The defect detection method of the in-service gas production tree valve stem defect detection system according to claim 4, characterized in that, The defect is characterized as a groove-shaped defect.

6. The defect detection method of the in-service gas production tree valve stem defect detection system according to claim 4, characterized in that, The ultrasonic phased array scan includes the following steps: Adjust the position and orientation of the ultrasonic probe of the ultrasonic phased array detection equipment to ensure that the ultrasonic probe and the end of the valve stem are concentric; Then, the ultrasonic phased array testing equipment is turned on, the center frequency and number of crystals of the corresponding ultrasonic probe are set, and the ultrasonic signal is excited by the ultrasonic transducer to perform ultrasonic probe rotation scanning.

7. The defect detection method of the in-service gas production tree valve stem defect detection system according to claim 6, characterized in that, The rotational scanning also includes the following steps: In the ultrasonic phased array detection device, the deflection angle is set by adjusting the focusing law, the focusing law of each crystal module around the end of the ultrasonic probe is adjusted in sequence, and the probe is excited in sequence. After being controlled by the focusing law, the ultrasonic beam is deflected toward the valve stem surface. The deflection angle of each crystal module is controlled by the ultrasonic phased array detection equipment. The angle is scanned from small to large to obtain the structural information of the circumferential surface of the valve stem. Input the actual depth of the specimen into the ultrasonic phased array instrument to obtain the propagation time required for the bottom wave signal echo of a single excitation; The intermittent working time of each chip module is set to the total time from the excitation of the ultrasonic beam to the single reception of the bottom wave signal. Several chip modules are excited in sequence to obtain the single scan result. Next, rotate the ultrasonic probe at a certain angle and perform several scans to cover the entire circumferential surface of the valve stem. Repeat the above steps for each scan. When rotating the ultrasonic probe at a certain angle, the center of the ultrasonic probe does not deviate from the center of the valve stem, and the vertical distance between the ultrasonic probe and the valve stem remains unchanged.

8. The defect detection method of the in-service gas production tree valve stem defect detection system according to claim 6, characterized in that, A gap for injecting coupling agent is left between the end of the ultrasonic probe and the end of the valve stem.

9. A defect detection method for an in-service gas production tree valve stem defect detection system according to claim 4, characterized in that, Before performing ultrasonic phased array scanning on the comparative specimen, the sound velocity of the phased array probe must be calibrated.

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