High-temperature-resistant electromagnetic flaw detector and test process

Abstract

The high-temperature-resistant electromagnetic flaw detector comprises a temperature measuring unit, a heat insulation unit, a heat absorption unit, a probe unit, a circuit unit, a power supply unit and a vacuum bottle, the temperature measurement unit, the heat insulation unit, the heat absorption unit, the probe unit, the circuit unit and the power supply unit are all arranged in the vacuum bottle and are all fixedly mounted on the instrument framework; the temperature measuring unit and the probe unit are respectively connected with the circuit unit; the power supply unit is connected with the circuit unit. The heat insulation technology of multi-section phase change heat absorption, end heat insulation and titanium alloy heat preservation is adopted, the heat absorption body absorbs heat of the internal main sensor, and the heat insulation body and the vacuum bottle isolate the influence of external high temperature of the electromagnetic flaw detector. According to the structure, the overall temperature resistance of the electromagnetic flaw detector is effectively improved, and the problem that high-temperature thermal recovery block sleeve detection cannot be realized in the prior art is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas exploitation, and particularly relates to a high-temperature resistant electromagnetic flaw detector and a testing process. Background Art

[0002] The electromagnetic flaw detector can detect the damage of tubing and casing in the tubing, or detect the damage of casing and surface casing in the casing. Therefore, logging with an electromagnetic flaw detector can be used for general oil well surveys, evaluate the degree of casing damage, understand and prevent the expansion of casing damage in regions, and take timely measures. The electromagnetic flaw detector logging technology has successfully solved problems such as detecting the thickness, corrosion, deformation and rupture of tubing and casing in the tubing, can accurately indicate the downhole string structure and tool position, and can detect ferromagnetic substances outside the casing, such as casing centralizers and surface casing.

[0003] In some oil fields, the temperature in the wellbore of the thermal recovery block can reach 200°C. There are a large number of casing damage wells that need to be evaluated. In the upper well section of the steam chamber, there are casing damage problems such as breakage, diameter reduction, perforation and distortion, which seriously restrict production safety. At present, the logging instrument indicators are all positioned at a temperature resistance of 175°C to meet the on-site requirements of non-thermal recovery blocks. Due to limitations in instrument circuits, sealing structures, signal temperature compensation technologies, etc., it is impossible to reach the index requirement of 220°C temperature resistance in high-temperature thermal recovery blocks, thus unable to meet the casing damage well evaluation requirements. Therefore, it is urgent to conduct research and development in instrument manufacturing, testing processes, and interpretation methods to achieve casing detection in high-temperature thermal recovery blocks. Summary of the Invention

[0004] In view of the above problems, the present invention discloses a high-temperature resistant electromagnetic flaw detector, including: a temperature measurement unit, a heat insulation unit, a heat absorption unit, a probe unit, a circuit unit, a power supply unit, and a thermos flask;

[0005] The temperature measurement unit, heat insulation unit, heat absorption unit, probe unit, circuit unit, and power supply unit are all arranged inside the thermos flask and are all fixedly installed on the instrument skeleton;

[0006] The temperature measurement unit and the probe unit are respectively connected to the circuit unit;

[0007] The power supply unit is connected to the circuit unit.

[0008] In some embodiments, the temperature measurement unit includes an outer temperature probe and an inner temperature probe;

[0009] The outer temperature probe is arranged at one end inside the thermos flask;

[0010] The inner temperature probe is located on the right side of the outer temperature probe.

[0011] In some embodiments, the heat insulation unit includes a heat insulation body;

[0012] The heat insulation body is arranged between the outer temperature probe and the inner temperature probe.

[0013] In some embodiments, the heat absorption unit includes a first heat absorption body, a second heat absorption body, and a third heat absorption body;

[0014] The first heat absorption body, the second heat absorption body, and the third heat absorption body are arranged at intervals from left to right on the right side of the heat insulation body.

[0015] In some embodiments, the probe unit includes natural gamma acquisition and a C probe;

[0016] The natural gamma acquisition is arranged on the right side of the first heat absorption body;

[0017] The inner temperature probe is arranged between the natural gamma acquisition and the second heat absorption body;

[0018] The C probe is arranged between the inner temperature probe and the second heat absorption body.

[0019] In some embodiments, the probe unit further includes: a BB probe, a B probe, and an A probe;

[0020] The BB probe, the B probe, and the A probe are arranged at intervals in sequence between the second heat absorption body and the third heat absorption body.

[0021] In some embodiments, the circuit unit includes a first circuit board and a second circuit board;

[0022] The first circuit board and the second circuit board are arranged at intervals in sequence between the second heat absorption body and the BB probe;

[0023] The first circuit board is electrically connected to the outer temperature probe, the natural gamma acquisition, the inner temperature probe, and the C probe respectively;

[0024] The second circuit board is electrically connected to the BB probe and the B probe respectively.

[0025] In some embodiments, the circuit unit further includes: a third circuit board;

[0026] The third circuit board is arranged between the B probe and the A probe;

[0027] The third circuit board is electrically connected to the A probe.

[0028] In some embodiments, the power supply unit includes a power supply board;

[0029] The power supply board is arranged between the first circuit board and the second circuit board;

[0030] The power supply board is electrically connected to the first circuit board, the second circuit board, and the third circuit board respectively.

[0031] In some embodiments, the heat absorption unit is a solid-liquid phase change material.

[0032] In some embodiments, the solid-liquid phase change material is sodium dihydrogen phosphate dodecahydrate.

[0033] In some embodiments, the thermal insulator is polyetheretherketone material.

[0034] In some embodiments, the thermos bottle includes a bottle mouth sealing sleeve, a bottle mouth ring, a pressure-bearing shell, a bottle inner tube and an instrument frame;

[0035] The inner tube of the bottle is inserted into an instrument frame on which a temperature measuring unit, a heat insulation unit, a heat absorption unit, a probe unit, a circuit unit and a power supply unit are fixedly installed;

[0036] The instrument frame is arranged inside the pressure-bearing shell and is threadedly connected to the inner wall of the bottom of the pressure-bearing shell;

[0037] The bottle mouth ring is threadedly connected to the pressure-bearing shell;

[0038] The bottle mouth sealing sleeve is threadedly connected with the bottle mouth ring.

[0039] In some embodiments, the thermos bottle further comprises: a bottle bottom sealing head;

[0040] The bottle bottom sealing head is connected to the outer wall of the bottom of the pressure-bearing shell.

[0041] In some embodiments, the thermos bottle is made of titanium alloy.

[0042] In some embodiments, the operating temperature inside the thermos bottle does not exceed a first temperature threshold.

[0043] The present invention also discloses a testing process based on the above-mentioned high temperature resistant electromagnetic flaw detector, comprising the following steps:

[0044] Vertical blowout preventer;

[0045] Place the logging vehicle and crane in the upwind direction according to the well site wind direction. If the well site conditions do not allow, the upwind direction is the primary placement direction, and the side wind direction is the secondary placement direction. The logging vehicle winch is aimed at the test wellhead and the instrument cabin is opened to prepare;

[0046] Install the sky and earth pulleys;

[0047] After the electromagnetic flaw detector is debugged on the ground, it is lowered into the test well. The cable lowering speed is controlled at the first set speed. The speed should be kept uniform during the lowering process, and retesting should be carried out when necessary.

[0048] Monitor the value of the external temperature probe of the electromagnetic flaw detector. If it exceeds the second temperature threshold, the electromagnetic flaw detector is powered off, the lowering is stopped, and the electromagnetic flaw detector is lifted up for testing; if it does not exceed the second temperature threshold, continue to lower until the target section;

[0049] Monitor the value of the internal temperature probe of the electromagnetic flaw detector. If it exceeds the first temperature threshold, the electromagnetic flaw detector is powered off, the lowering is stopped, and the electromagnetic flaw detector is lifted up for testing; if it does not exceed the first temperature threshold, continue to lower until the target section;

[0050] During the lifting process of the electromagnetic flaw detector, the lifting speed should be controlled within the first set speed. When the electromagnetic flaw detector is lifted to within the first set distance from the wellhead, the lifting speed should be controlled within the second set speed. When in the deviated well section, casing deformation, at the distance from the casing shoe and at the second set distance from the wellhead, the lifting speed should be controlled within the third set speed. After the electromagnetic flaw detector is lifted to the wellhead, there should be an operator holding the electromagnetic flaw detector by hand to avoid damage to the electromagnetic flaw detector caused by collision;

[0051] Count the test tools and put them into the toolbox; disassemble and recycle the electromagnetic flaw detector for wellhead testing, and restore the wellhead to its original state.

[0052] In some embodiments, the first set speed is 30 m / min.

[0053] In some embodiments, the second set speed is 20 m / min.

[0054] In some embodiments, the third set speed is 10 m / min.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows: An insulation technology of multi-stage phase change heat absorption + end heat insulation + titanium alloy heat preservation is adopted. The heat absorber absorbs the heat of the internal main sensor, and the heat insulator and thermos flask isolate the influence of the external high temperature of the electromagnetic flaw detector. This structure effectively improves the overall temperature resistance performance of the electromagnetic flaw detector and solves the problem that the prior art cannot realize the casing detection in high-temperature thermal recovery blocks.

[0056] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained by the structure pointed out in the specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0058] Figure 1 shows the external schematic diagram of a high-temperature-resistant electromagnetic flaw detector according to an embodiment of the present invention;

[0059] Figure 2 shows the internal schematic diagram of a high-temperature-resistant electromagnetic flaw detector according to an embodiment of the present invention;

[0060] Figure 3 shows the flowchart of a test process according to an embodiment of the present invention.

[0061] Reference numerals: 1, external temperature probe; 2, heat insulation body; 3, first heat absorber; 4, natural gamma acquisition; 5, internal temperature probe; 6, C probe; 7, second heat absorber; 8, first circuit board; 9, power supply board; 10, second circuit board; 11, BB probe; 12, B probe; 13, third circuit board; 14, A probe; 15, third heat absorber; 16, thermos bottle; 16-1, bottle mouth seal; 16-2, bottle mouth ring; 16-3, pressure-bearing outer shell; 16-4, inner bottle tube; 16-5, bottle bottom seal head. Detailed implementation manners

[0062] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0063] As Figure 1 and Figure 2 shown, a high-temperature-resistant electromagnetic flaw detector proposed by the present invention includes: a temperature measurement unit, a heat insulation unit, a heat absorption unit, a probe unit, a circuit unit, a power supply unit and a thermos bottle 16;

[0064] The temperature measurement unit, the heat insulation unit, the heat absorption unit, the probe unit, the circuit unit and the power supply unit are all arranged inside the thermos bottle 16 and are all fixedly installed on the instrument skeleton, that is, the inner part of the bottle is formed;

[0065] The temperature measurement unit and the probe unit are respectively connected to the circuit unit;

[0066] The power supply unit is connected to the circuit unit.

[0067] The temperature measurement unit is used to measure the external and internal temperatures of the high-temperature-resistant electromagnetic flaw detector;

[0068] The heat insulation unit is used to isolate the external high temperature of the high-temperature-resistant electromagnetic flaw detector;

[0069] An endothermic unit for absorbing the heat generated by the internal electronic devices of a high-temperature-resistant electromagnetic flaw detector;

[0070] A probe unit for detection;

[0071] A circuit unit for collecting and processing the signals of the probe unit;

[0072] A power supply unit for supplying power to the electronic devices;

[0073] A thermos 16 for isolating the external high temperature of the high-temperature-resistant electromagnetic flaw detector.

[0074] The present invention adopts a heat insulation technology of multi-stage phase change endothermic + end heat insulation + titanium alloy heat preservation. The endothermic body absorbs the heat of the internal main sensor, and the heat insulation bodies 2 and the thermos 16 isolate the influence of the external high temperature of the electromagnetic flaw detector, thus solving the key problems such as the temperature resistance of the circuit and the overall high-temperature protection. This structure effectively improves the overall temperature resistance performance of the electromagnetic flaw detector, solves the problem that the existing technology cannot realize the detection of the casing of the high-temperature thermal recovery block, and fills the gap in the detection technology of damaged wells in high-temperature environments.

[0075] In some embodiments, the temperature measurement unit includes an external temperature probe 1 and an internal temperature probe 5;

[0076] The external temperature probe 1 is arranged at the head end inside the thermos 16;

[0077] The internal temperature probe 5 is located on the right side of the external temperature probe 1.

[0078] The external temperature probe 1 is used for measuring the external temperature;

[0079] The internal temperature probe 5 is used for real-time monitoring of the internal temperature of the electromagnetic flaw detector, making the overall internal temperature of the electromagnetic flaw detector controllable and protecting the internal circuit. If the temperature measured by the internal temperature probe 5 is greater than the threshold value, the power-off program is started to protect the internal circuit.

[0080] In some embodiments, the heat insulation unit includes a heat insulation body 2;

[0081] The heat insulation body 2 is arranged between the external temperature probe 1 and the internal temperature probe 5.

[0082] The heat insulation body 2 is placed at the rear end of the external temperature probe 1 and the front end of the first endothermic body 3, and is used for isolating the influence of the external high temperature of the electromagnetic flaw detector.

[0083] In some embodiments, the heat insulation body 2 is made of polyetheretherketone material. Polyetheretherketone (PEEK) is a special engineering plastic with excellent properties such as high temperature resistance, self-lubrication, easy processing, and high mechanical strength.

[0084] In some embodiments, the endothermic unit includes a first endothermic body 3, a second endothermic body 7, and a third endothermic body 15;

[0085] The first heat absorber 3, the second heat absorber 7, and the third heat absorber 15 are sequentially arranged at intervals from left to right on the right side of the heat insulation body 2.

[0086] The first heat absorber 3 is used to absorb the heat of the heat insulation body 2 and the natural gamma acquisition 4, so as to achieve temperature resistance of the electromagnetic flaw detector circuit and overall high-temperature protection;

[0087] The second heat absorber 7 is used to absorb the heat of the C probe 6, the first circuit board 8, the power supply board 9, the second circuit board 10, and the BB probe 11;

[0088] The third heat absorber 15 is used to absorb the heat of the B probe 12, the third circuit board 13, and the A probe 14.

[0089] Multi-stage phase change heat absorption is achieved by placing multiple heat absorbers at the circuit board and the probe, and using the principle of phase change heat absorption to absorb the heat of the internal main sensor to achieve the purpose of temperature resistance of the circuit. The number of multi-stage phase change heat absorption segments can be increased or decreased according to actual test requirements, and the placement position can be flexibly changed. Considering the function and length of the high-temperature resistant electromagnetic flaw detector, preferably, three-stage phase change heat absorption is adopted.

[0090] In some embodiments, the heat absorption unit is a solid-liquid phase change material.

[0091] The solid-liquid phase change material can be higher aliphatic hydrocarbons (n-hexadecane, n-octadecane, paraffin, etc.), fatty acids and their esters (stearic acid, palmitic acid, etc.), crystalline hydrated salts (Na2SO4·10H2O, Mn(NO3)2·6H2O, etc.), molten salts (LiF, NaF, CaF2, etc.), metals and alloys (lead-tin alloy, etc.), polymers (polyethylene glycol, etc.), and sodium dihydrogen phosphate dodecahydrate.

[0092] Preferably, the solid-liquid phase change material is sodium dihydrogen phosphate dodecahydrate.

[0093] Ensure that the high-temperature resistant electromagnetic flaw detector can be used normally under the condition that the external temperature is greater than 220°C.

[0094] In some embodiments, the probe unit includes a natural gamma acquisition 4 and a C probe 6;

[0095] The natural gamma acquisition 4 is arranged on the right side of the first heat absorber 3;

[0096] The internal temperature probe 5 is arranged between the natural gamma acquisition 4 and the second heat absorber 7;

[0097] The C probe 6 is arranged between the internal temperature probe 5 and the second heat absorber 7.

[0098] The natural gamma acquisition 4 is used for measuring the formation gamma for the next depth calibration;

[0099] C probe 6, for collecting proximal longitudinal signals.

[0100] In some embodiments, the probe unit further includes: BB probe 11, B probe 12, and A probe 14;

[0101] The BB probe 11, B probe 12, and A probe 14 are sequentially arranged at intervals between the second heat absorber 7 and the third heat absorber 15.

[0102] BB probe 11, for collecting transverse signals;

[0103] B probe 12, for collecting transverse signals;

[0104] A probe 14, for collecting distal longitudinal signals.

[0105] In some embodiments, the circuit unit includes a first circuit board 8 and a second circuit board 10;

[0106] The first circuit board 8 and the second circuit board 10 are sequentially arranged at intervals between the second heat absorber 7 and the BB probe 11;

[0107] The first circuit board 8 is electrically connected to the external temperature probe 1, natural gamma acquisition 4, internal temperature probe 5, and C probe 6 respectively;

[0108] The second circuit board 10 is electrically connected to the BB probe 11 and the B probe 12 respectively.

[0109] The first circuit board 8 is used to process the signals of the C probe 6, converting analog signals into digital signals;

[0110] The second circuit board 10 is used to process the signals of the BB probe 11 and the B probe 12, converting analog signals into digital signals.

[0111] In some embodiments, the circuit unit further includes: a third circuit board 13;

[0112] The third circuit board 13 is arranged between the B probe 12 and the A probe 14;

[0113] The third circuit board 13 is electrically connected to the A probe 14.

[0114] The third circuit board 13 is used to process the signals of the A probe 14, converting analog signals into digital signals.

[0115] The first circuit board 8, the second circuit board 10, and the third circuit board 13 are connected to the ground equipment through cables.

[0116] In some embodiments, the power supply unit includes a power supply board 9;

[0117] The power board 9 is arranged between the first circuit board 8 and the second circuit board 10;

[0118] The power board 9 is electrically connected to the first circuit board 8 , the second circuit board 10 and the third circuit board 13 respectively.

[0119] The power supply board 9 is connected to the ground power supply through a cable.

[0120] The power board 9 is used to supply power to the circuit board.

[0121] In some embodiments, the thermos bottle 16 includes a bottle mouth sealing sleeve 16-1, a bottle mouth ring 16-2, a pressure-bearing shell 16-3, a bottle inner tube 16-4 and an instrument frame;

[0122] The inner tube 16-4 of the bottle penetrates into the instrument skeleton (i.e., the inner tube 16-4 of the bottle penetrates into the connected inner part of the bottle) on which the temperature measuring unit, the heat insulation unit, the heat absorption unit, the probe unit, the circuit unit and the power supply unit are fixedly installed;

[0123] The instrument skeleton is arranged inside the pressure-bearing shell 16-3 and is threadedly connected to the inner wall of the bottom of the pressure-bearing shell 16-3;

[0124] The bottle mouth ring 16-2 is threadedly connected to the top of the pressure-bearing shell 16-3;

[0125] The bottle mouth sealing sleeve 16 - 1 is threadedly connected to the bottle mouth ring 16 - 2 .

[0126] Bottle mouth sealing sleeve 16-1, used for connecting the upper end centralizer of the electromagnetic flaw detector;

[0127] A bottle mouth ring 16-2, used for sealing the thermos bottle 16;

[0128] The pressure-bearing shell 16-3 is used for bearing the overall pressure of the electromagnetic flaw detector;

[0129] The inner tube 16-4 of the bottle is used for internal heat insulation of the electromagnetic flaw detector;

[0130] The instrument frame is used to connect the internal components of the electromagnetic flaw detector.

[0131] The shell of the thermos flask 16 adopts a combined titanium alloy instrument frame and a large diameter long thermos flask shell structure to ensure that the temperature inside the bottle does not exceed 150°C and the maximum pressure resistance is 80MPa under an ambient temperature of 220°C and a single maximum working time of 4 hours. All materials of the thermos flask 16 must be absolutely non-magnetic. The above structure enables the instrument frame to maintain structural strength, the electromagnetic flaw detector core to achieve external heat insulation, and the overall magnetic permeability and pressure resistance indicators are achieved to achieve overall high temperature protection.

[0132] In some embodiments, the thermos bottle 16 further includes: a bottle bottom sealing head 16-5;

[0133] The bottle bottom sealing head 16-5 is connected to the outer wall of the bottom of the pressure-bearing shell 16-3.

[0134] The bottle bottom sealing head 16-5 is used to seal the bottle body of the electromagnetic flaw detector and connect the lower end centralizer.

[0135] In some embodiments, the thermos bottle 16 is made of titanium alloy.

[0136] Advantages of titanium alloy: 1. Titanium alloy has excellent mechanical properties and a very high strength-to-mass ratio. 2. Good corrosion resistance, high and low temperature resistance, can be used between -253℃ and 600℃. 3. Low density, strong wear resistance, good wear resistance. 4. Super toughness, can withstand large deformation, easy to stamp. 5. High surface hardness, not easy to fall off and damage.

[0137] In some embodiments, the working temperature inside the thermos bottle 16 does not exceed a first temperature threshold. Exemplarily, the first temperature threshold is 150°C.

[0138] like Figure 3 As shown, based on the above-mentioned high temperature resistant electromagnetic flaw detector, the present invention also discloses a testing process, comprising the following steps:

[0139] Step 1, erect the blowout preventer;

[0140] Step 2: Place the logging vehicle and crane in the upwind direction according to the wind direction of the well site. If the well site conditions do not allow, the upwind direction is the primary placement direction, and the side wind direction is the secondary placement direction. The winch of the logging vehicle is aimed at the test wellhead, and the instrument cabin is opened and ready;

[0141] Step 3: Set up a cordon at the site, place safety signs, set up escape routes, and prohibit non-staff from entering;

[0142] Step 4: Install the top and bottom pulleys;

[0143] Step 5. After the electromagnetic flaw detector is debugged on the ground, it is lowered into the test well. The cable lowering speed is controlled at the first set speed. The speed should be kept uniform during the lowering process, and retesting should be performed if necessary.

[0144] Step 6, monitor the value of the external temperature probe 1 of the electromagnetic flaw detector. If it exceeds the second temperature threshold, the electromagnetic flaw detector is powered off, the lowering is stopped, and the electromagnetic flaw detector is pulled up for testing according to the speed requirement of step 8; if it does not exceed the second temperature threshold, it continues to be lowered to the destination section; illustratively, the second temperature threshold is 220°C.

[0145] Step 7: Monitor the value of the internal temperature probe 5 of the electromagnetic flaw detector. If it exceeds the first temperature threshold, power off the electromagnetic flaw detector, stop lowering, and raise the electromagnetic flaw detector to conduct tests according to the speed requirements in Step 8. If it does not exceed the first temperature threshold, continue to lower until the target section.

[0146] Step 8: During the raising process of the electromagnetic flaw detector, the raising speed should be controlled within the first set speed. When the electromagnetic flaw detector is raised to within the first set distance from the wellhead, the raising speed should be controlled within the second set speed. When in the deviated well section, casing deformation, at a distance from the casing shoe and at the second set distance from the wellhead, the raising speed should be controlled within the third set speed. After the electromagnetic flaw detector is raised to the wellhead, an operator should hold the electromagnetic flaw detector by hand to prevent it from being damaged by collision. Exemplarily, the first set distance is 100m; the second set distance is 50m.

[0147] Step 9: Count the test tools and put them into the toolbox; disassemble and recycle the electromagnetic flaw detector for wellhead testing, and restore the wellhead to its original state.

[0148] In some embodiments, the first set speed is 30m / min.

[0149] In some embodiments, the second set speed is 20m / min.

[0150] In some embodiments, the third set speed is 10m / min.

[0151] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-temperature resistant electromagnetic flaw detector, characterized in that, Comprising: a temperature measurement unit, a heat insulation unit, a heat absorption unit, a probe unit, a circuit unit, a power supply unit, and a thermos flask (16); the temperature measurement unit, the heat insulation unit, the heat absorption unit, the probe unit, the circuit unit, and the power supply unit are all arranged inside the thermos flask (16) and are fixedly installed on the instrument skeleton; the temperature measurement unit and the probe unit are respectively connected to the circuit unit; the power supply unit is connected to the circuit unit.

2. The high-temperature resistant electromagnetic flaw detector according to claim 1, characterized in that, The temperature measurement unit includes an outer temperature probe (1) and an inner temperature probe (5); the outer temperature probe (1) is arranged at one end inside the thermos flask (16); the inner temperature probe (5) is located on the right side of the outer temperature probe (1).

3. The high-temperature resistant electromagnetic flaw detector according to claim 2, characterized in that, The heat insulation unit includes a heat insulator (2); the heat insulator (2) is arranged between the outer temperature probe (1) and the inner temperature probe (5).

4. The high-temperature resistant electromagnetic flaw detector according to claim 3, characterized in that, The heat absorption unit includes a first heat absorber (3), a second heat absorber (7), and a third heat absorber (15); the first heat absorber (3), the second heat absorber (7), and the third heat absorber (15) are arranged at intervals from left to right on the right side of the heat insulator (2).

5. The high-temperature resistant electromagnetic flaw detector according to claim 4, characterized in that, The probe unit includes a natural gamma acquisition (4) and a C probe (6); the natural gamma acquisition (4) is arranged on the right side of the first heat absorber (3); the inner temperature probe (5) is arranged between the natural gamma acquisition (4) and the second heat absorber (7); the C probe (6) is arranged between the inner temperature probe (5) and the second heat absorber (7).

6. The high-temperature resistant electromagnetic flaw detector according to claim 5, wherein, The probe unit further includes: a BB probe (11), a B probe (12), and an A probe (14); the BB probe (11), the B probe (12), and the A probe (14) are arranged at intervals in sequence between the second heat absorber (7) and the third heat absorber (15).

7. The high-temperature resistant electromagnetic flaw detector according to claim 6, wherein, The circuit unit includes a first circuit board (8) and a second circuit board (10); the first circuit board (8) and the second circuit board (10) are arranged at intervals in sequence between the second heat absorber (7) and the BB probe (11); the first circuit board (8) is electrically connected to the outer temperature probe (1), the natural gamma acquisition (4), the inner temperature probe (5), and the C probe (6) respectively; the second circuit board (10) is electrically connected to the BB probe (11) and the B probe (12) respectively.

8. The high-temperature resistant electromagnetic flaw detector according to claim 7, characterized in that, The circuit unit further includes: a third circuit board (13); the third circuit board (13) is arranged between the B probe (12) and the A probe (14); the third circuit board (13) is electrically connected to the A probe (14).

9. The high-temperature resistant electromagnetic flaw detector according to claim 8, wherein The power supply unit includes a power supply board (9); the power supply board (9) is arranged between the first circuit board (8) and the second circuit board (10); the power supply board (9) is electrically connected to the first circuit board (8), the second circuit board (10), and the third circuit board (13) respectively.

10. The high-temperature resistant electromagnetic flaw detector according to claim 4, wherein, The heat absorption unit is a solid-liquid phase change material.

11. The high-temperature resistant electromagnetic flaw detector according to claim 10, characterized in that, The solid-liquid phase change material is sodium dihydrogen phosphate dodecahydrate.

12. The high-temperature resistant electromagnetic flaw detector according to claim 3, wherein, The heat insulator (2) is made of polyether ether ketone material.

13. The high-temperature resistant electromagnetic flaw detector according to claim 1, wherein The thermos flask (16) includes a bottle mouth seal sleeve (16-1), a bottle mouth ring (16-2), a pressure-bearing outer shell (16-3), an inner bottle tube (16-4), and an instrument skeleton; The inner tube (16-4) of the bottle is inserted into an instrument frame on which a temperature measuring unit, a heat insulating unit, a heat absorbing unit, a probe unit, a circuit unit and a power supply unit are fixedly installed; The instrument frame is arranged inside the pressure-bearing shell (16-3) and is threadedly connected to the inner wall of the bottom of the pressure-bearing shell (16-3); The bottle mouth ring (16-2) is threadedly connected to the pressure-bearing shell (16-3); The bottle mouth sealing sleeve (16-1) is threadedly connected to the bottle mouth ring (16-2).

14. The high-temperature resistant electromagnetic flaw detector according to claim 13, characterized in that, The thermos bottle (16) further comprises: a bottle bottom sealing head (16-5); The bottle bottom sealing head (16-5) is connected to the outer wall of the bottom of the pressure-bearing shell (16-3).

15. The high-temperature resistant electromagnetic flaw detector according to claim 1, wherein The thermos bottle (16) is made of titanium alloy.

16. The high-temperature resistant electromagnetic flaw detector according to claim 1, characterized in that, The operating temperature inside the thermos bottle (16) does not exceed a first temperature threshold.

17. A testing process for a high-temperature resistant electromagnetic flaw detector according to any one of claims 1-16, characterized in that, The following steps are involved: Vertical blowout preventer; Place the logging vehicle and crane in the upwind direction according to the well site wind direction. If the well site conditions do not allow, the upwind direction is the primary placement direction, and the side wind direction is the secondary placement direction. The logging vehicle winch is aimed at the test wellhead and the instrument cabin is opened to prepare; Install the sky and earth pulleys; After the electromagnetic flaw detector is debugged on the ground, it is lowered into the test well. The cable lowering speed is controlled at the first set speed. The speed should be kept uniform during the lowering process, and retesting should be carried out when necessary. Monitoring the value of the external temperature probe (1) of the electromagnetic flaw detector. If the value exceeds a second temperature threshold, the electromagnetic flaw detector is powered off, the lowering is stopped, and the electromagnetic flaw detector is lifted up for testing. If the value does not exceed the second temperature threshold, the electromagnetic flaw detector continues to be lowered until it reaches the target section. Monitor the value of the temperature probe (5) inside the electromagnetic flaw detector. If the value exceeds a first temperature threshold, the electromagnetic flaw detector is powered off, the lowering is stopped, and the electromagnetic flaw detector is lifted up for testing. If the value does not exceed the first temperature threshold, the electromagnetic flaw detector continues to be lowered until it reaches the target section. During the lifting process of the electromagnetic flaw detector, the lifting speed should be controlled within the first set speed. When the electromagnetic flaw detector is pulled up to within the first set distance from the wellhead, the lifting speed should be controlled within the second set speed. In the inclination section, casing change, distance from the casing shoe and the second set distance from the wellhead, the lifting speed should be controlled within the third set speed. After the electromagnetic flaw detector is pulled up to the wellhead, an operator should hold the electromagnetic flaw detector by hand to prevent the electromagnetic flaw detector from being damaged by collision; Count the test tools and put them into the tool box; dismantle and recover the wellhead test electromagnetic flaw detector and restore the wellhead to its original state.

18. The test process according to claim 17, wherein The first set speed is 30 m / min.

19. The test process according to claim 17, characterized in that, The second set speed is 20 m / min.

20. The test process according to claim 17, characterized in that, The third set speed is 10 m / min.

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