Device and method for accurately positioning and precisely detecting leakage of whole shaft of oil and gas well

Abstract

The invention relates to the technical field of oil field oil production engineering, in particular to an oil and gas well whole shaft accurate positioning and precise leakage detection device and method. The device comprises a guide head, wherein the upper end of the guide head is sequentially connected with a positioner, a packer, a check valve and a coiled tubing; the positioner comprises a central pipe, and a positioning outer sleeve is fixed on the outer side of the central pipe and connected with a positioner limiting sleeve. The packer comprises a central connecting pipe, a central connecting pipe connecting rubber sleeve, a conical body, a packer inner sleeve, a packer outer sleeve and a track sleeve, the packer inner sleeve is connected with a clamping piece mechanism, and the clamping piece mechanism is connected with a fixing piece mechanism and the track sleeve; the check valve comprises an upper connector, the upper connector is connected with a check valve limiting sleeve and a check valve inner sleeve, the check valve inner sleeve is connected with a check valve outer sleeve, the check valve inner sleeve is connected with a T-shaped packing mechanism, and the T-shaped packing mechanism is connected with a pressing ring mechanism. According to the oil and gas well whole shaft accurate positioning and precise leakage detection device and method, accurate positioning is achieved, and continuous and rapid whole well precise leakage detection is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of oil field production engineering, and in particular to a device and method for accurately positioning and detecting leaks in the entire wellbore of an oil and gas well. Background Art

[0002] In the field of oil fields, all kinds of wells are very important. Whether it is an oil and gas well or a water well, once leakage occurs, the consequences cannot be underestimated. Among them, the leakage of oil and gas wells has a great impact. Generally speaking, in oil and gas wells, leaking wells with good potential can still achieve subsequent downhole operations through repair or fracturing; wellheads with serious leakage can only abandon operations, and economic and labor losses are very serious. Although leaking wells can be solved by repairs, it is more important to detect leaks in advance than to take measures to save them after leakage occurs. In fact, most leaking wells do not have devices and methods to quickly and accurately find the leakage point and accurately detect leaks, which makes it impossible for workers to tap the potential of these leaking wells with good potential, which not only seriously affects production, but also damages benefits. Therefore, in view of the above shortcomings, a device and method for accurate positioning and precise leak detection of the entire wellbore of oil and gas wells is proposed. Summary of the invention

[0003] 1. Technical issues to be resolved The present invention provides a device and method for accurate positioning of the entire wellbore of an oil and gas well, thereby avoiding the problems in existing methods such as the inability to quickly detect leaks, the inability to accurately position and accurately detect leaks, resulting in low leak detection efficiency in leaking wells in oil fields, and the occurrence of unexplained leakage in the entire wellbore of the oil and gas well, which affects production and benefits.

[0004] (II) Technical solution In order to solve the above problems, the present invention provides an accurate positioning and precise leak detection device for the entire wellbore of an oil and gas well, comprising: A guide head, the upper end of which is sequentially connected to a positioner, a packer, a check valve and a coiled tubing; The positioner comprises a central tube, the outer side of the central tube is fixed to the outer sleeve by a positioner pin, a protrusion is provided on the outer side of the positioning outer sleeve, and the lower side of the positioning outer sleeve is connected to the positioner limiting sleeve by a thread; The packer comprises a central connecting tube, the outer side of the central connecting tube is connected to a rubber tube, a cone, a packer inner sleeve, a packer outer sleeve and a track sleeve, the rubber tube is connected to the cone, the cone and the central connecting tube are sealed by a sealing rubber ring, the sealing rubber ring is connected to a gasket, the outer side of the packer inner sleeve is connected to a card mechanism, the card mechanism is connected to a fixing plate mechanism through a locking ring, the outer side of the fixing plate mechanism is connected to the packer outer sleeve, and the bottom end of the card mechanism is connected to the track sleeve; The check valve includes an upper joint, the outer side of the upper joint is connected to the check valve limiting sleeve, the bottom end of the upper joint is connected to the check valve inner sleeve, the outer side of the check valve inner sleeve is connected to the check valve outer sleeve, the check valve limiting sleeve is connected to the check valve outer sleeve, the outer side of the lower end of the check valve inner sleeve is connected to a T-type packing mechanism, and the T-type packing mechanism is connected to a pressure ring mechanism.

[0005] Preferably, the card mechanism comprises a card sleeve, a card and a card spring, the two ends of the card sleeve are a card and a locking ring respectively, and the card is provided with a card spring.

[0006] Preferably, the fixing plate mechanism includes a fixing plate and a fixing leaf spring, the upper end of the fixing plate is a locking ring, two fixing leaf springs are provided on the fixing plate, the outer side of the fixing plate is connected to the packer sleeve through a packer pin, and the bottom end of the fixing plate is connected to the track sleeve through a track pin.

[0007] Preferably, the T-shaped packing mechanism comprises two T-shaped packings, the pressure ring mechanism comprises a pressure ring and a pressure cap, the two T-shaped packings are connected, a pressure ring is provided between the two T-shaped packings, and the T-shaped packing at the tail end is connected to the pressure cap.

[0008] Preferably, the check valve limiting sleeve and the upper joint are sealed by a sealing ring, the check valve limiting sleeve is connected to the check valve outer sleeve through a check valve pin, and the check valve inner sleeve is connected to the upper joint through a check valve pin.

[0009] Preferably, the coiled tubing is provided with a monitoring meter and a counter, the monitoring meter monitors the change of the hanging weight during the running of the coiled tubing into the well in real time, and the counter measures the running depth of the coiled tubing into the well in real time.

[0010] The present invention also provides a method for accurately positioning a precision leak detection device based on the entire wellbore of an oil and gas well, comprising: Step S1: Complete the connection of the leak detection device and lower the connected leak detection device to the bottom of the well; Step S2: lifting the fracturing string, measuring the short casing depth by the positioner, verifying the acquired short casing depth according to the short casing depth and length data in the acoustic amplitude logging data after the well completion, calculating the error between the running depth of the coiled tubing and the logging depth, and preliminarily determining the location of the leakage point by the error value; Step S3: According to the preliminary position of the leakage point obtained in step S2, the packer is set by lifting and lowering the coiled tubing, and the check valve is closed at the same time to seal the coiled tubing, and the pressure check is used to reduce leakage and reduce the leakage detection error. After setting, the hanging weight of the monitoring meter returns to 0, and the coiled tubing is pressed down so that the hanging weight range of the monitoring meter is displayed in 20-30kN; Step S4: pressurizing the casing inside the wellhead, and obtaining whether leakage occurs at the current well depth by monitoring the changes in the pressure gauge; Step S5: If the depth monitored in step S4 is not leaking, lift the pipe string to the wellhead and half of the current depth, repeat steps S3 and S4, and cycle in sequence until the leakage point is found; Step S6: After the leakage point is determined, the test is terminated, the casing is depressurized, and the device is disassembled, and the leakage point is subsequently repaired.

[0011] Preferably, in step S2, each time the positioner passes through a casing coupling, the suspended weight monitored by the monitoring meter increases in the range of 10-20 kN, and the number of casing couplings passed through is determined by the suspended weight.

[0012] Preferably, in step S2, the error value is the difference between the well depth and the logging depth, and the preliminary position of the leakage point is the difference between the well depth and the error value.

[0013] Preferably, in step S5, the pressure value of the pressure gauge is stable, indicating that there is no leakage from the wellhead to this depth; if the pressure value of the pressure gauge continues to decrease, it indicates that leakage occurs in this section.

[0014] (III) Beneficial effects The device and method for accurate positioning and precise leak detection of the entire wellbore of an oil and gas well provided by the present invention can accurately position and realize continuous and rapid precise leak detection of the entire well, effectively solving the problems of unexplained leakage of the entire wellbore of an oil and gas well, inability to quickly detect leaks, and inability to accurately position and precisely detect leaks. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of a device for accurately positioning a precise leak detection device for an oil and gas well in the entire wellbore according to an embodiment of the present invention; Figure 2 It is a structural schematic diagram of a positioner according to an embodiment of the present invention; Figure 3 It is a structural schematic diagram of a packer according to an embodiment of the present invention; Figure 4 This is a schematic structural diagram of a check valve according to an embodiment of the present invention; Figure 5 This is an application diagram of the check valve according to an embodiment of the present invention.

[0016] Among them: 1-guide head; 2-positioner; 3-packer; 4-check valve; 5-coiled tubing; 21-center tube; 22-positioning sleeve; 23-positioning pin; 24-positioning limit sleeve; 31-center connecting tube; 32-rubber cylinder; 33-sealing rubber ring; 34-washer; 35-cone; 36-card; 37-card spring; 38-packer inner sleeve; 39-card sleeve; 310-locking ring; 311-fixing plate; 312-fixing leaf spring; 313-packer pin; 314-packer outer sleeve; 315-track sleeve; 316-track pin; 41-upper joint; 42-sealing ring; 43-check valve pin; 44-check valve limit sleeve; 45-check valve inner sleeve; 46-check valve outer sleeve; 47-T-type packing; 48-pressure ring; 49-pressure cap. Implementation

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Figure 1 Schematic diagram of the structure of the device for accurately positioning the entire wellbore of an oil and gas well according to an embodiment of the present invention. Figure 1 As shown, the present invention provides a precise leak detection device for accurate positioning of the entire wellbore of an oil and gas well, comprising: A guide head 1, the upper end of which is connected to a positioner 2, the positioner 2 is connected to a packer 3, the packer is connected to a check valve 4, and the upper end of the check valve 4 is connected to a coiled tubing 5.

[0019] Figure 2 FIG. 1 is a schematic diagram of the structure of a positioner according to an embodiment of the present invention. Figure 2 As shown, the positioner 2 includes a center tube 21, the outer side of the center tube 21 is connected to a positioning sleeve 22 via a positioner pin 23, a protrusion is provided on the outer side of the positioning sleeve 22, and the bottom of the positioning sleeve 22 is connected to a positioner limiting sleeve 24 via a thread.

[0020] In actual application, the positioning sleeve 22 is hung on the outer wall of the central pipe 21. By lifting the pipe string, when the protrusion of the positioning sleeve 22 passes through the gap of the casing coupling, the hanging weight of the coiled tubing increases, and the lowering position of the device can be determined.

[0021] Figure 3 FIG. 1 is a schematic diagram of the structure of a packer according to an embodiment of the present invention. Figure 3As shown, the packer 3 includes a central connecting tube 31, the outer side of the central connecting tube 31 is connected to a rubber sleeve 32, a cone 35, a packer inner sleeve 38, a packer outer sleeve 314 and a track sleeve 315, the rubber sleeve 32 is connected to the cone 35, the outer side of the packer inner sleeve 38 is connected to a card mechanism, the card mechanism is connected to a fixing plate mechanism, the outer side of the fixing plate mechanism is connected to the packer outer sleeve 314, and the bottom end of the card mechanism is connected to the track sleeve 315.

[0022] Figure 4 is a schematic diagram of the structure of a check valve according to an embodiment of the present invention, Figure 5 FIG. 1 is an application diagram of a check valve according to an embodiment of the present invention, as shown in FIG. Figure 4 and Figure 5 As shown, the check valve 4 includes an upper joint 41, the outer side of the upper joint 41 is connected to a check valve limiting sleeve 44, the bottom end of the upper joint 41 is connected to a check valve inner sleeve 45, the outer side of the check valve inner sleeve 45 is connected to a check valve outer sleeve 46, the check valve limiting sleeve 44 is connected to the check valve outer sleeve 46, the outer side of the lower end of the check valve inner sleeve 45 is connected to a T-type packing mechanism, and the T-type packing mechanism is connected to a pressure ring mechanism.

[0023] In practical applications, the cone 35 and the central connecting tube 31 are sealed by a sealing rubber ring 33 , the sealing rubber ring 33 is connected to the gasket 34 , and the card mechanism is connected to the fixing plate mechanism through a locking ring 310 .

[0024] It should be noted that the card mechanism includes a card sleeve 39, a card 36 and a card spring 37. The two ends of the card sleeve 39 are a card 36 and a locking ring 310 respectively. The card 36 is provided with a card spring 37. In addition, the fixed plate mechanism includes a fixed plate 311 and a fixed leaf spring 312. The upper end of the fixed plate 311 is a locking ring 310. Two fixed leaf springs 32 are provided on the fixed plate 311. The outer side of the fixed plate 311 is connected to the packer sleeve 314 through the packer pin 313, and the bottom end of the fixed plate 311 is connected to the track sleeve 315 through the track pin 316.

[0025] In the leak detection device, the rubber cylinder 32, the card 33, the fixing plate 311 and the packer sleeve 314 are all hung on the outer wall of the central connecting tube 31. By lifting and lowering the central connecting tube 31, the track of the central connecting tube 31 is changed, the card 36 is disengaged, and the rubber cylinder 32 is sealed.

[0026] In actual application, the check valve limit sleeve 44 and the upper joint 41 are sealed by a sealing ring 42, the check valve limit sleeve 44 is connected to the check valve outer sleeve 46 through the check valve pin 43, and the check valve inner sleeve 45 is connected to the upper joint 41 through the check valve pin 43. In addition, the T-type packing mechanism includes two T-type packings 47, and the pressure ring mechanism includes a pressure ring 48 and a pressure cap 49. The two T-type packings 47 are connected, and the pressure ring 48 is between the two T-type packings 47. The T-type packing 47 at the tail end is connected to the pressure cap 49.

[0027] In this leakage detection device, a sealing ring 42 is installed in the check valve limiting sleeve 44, the check valve limiting sleeve 44 is inserted into the upper joint 41, the T-type packing 47 is inserted into the check valve inner sleeve 45, the pressure cap 49 is pressed on, the pressure ring 48 is tightened, the check valve inner sleeve 45 is threadedly connected to the upper joint 41, and the check valve outer sleeve 46 is threadedly connected to the check valve limiting sleeve 44. When the check valve 4 needs to be sealed, the upper joint 41 is pressed down to drive the T-type packing 47 to the check valve outer sleeve 46 to form a seal and pressure check.

[0028] In addition, the coiled tubing 5 is provided with a monitoring meter and a counter. The monitoring meter monitors the change of the hanging weight during the running of the coiled tubing into the well in real time, and the counter measures the running depth of the coiled tubing into the well in real time.

[0029] The present invention also provides a method for accurately positioning a precision leak detection device based on the entire wellbore of an oil and gas well, comprising: Step S1: Complete the connection of the leak detection device and lower the connected leak detection device to the bottom of the well; Step S2: lifting the fracturing string, measuring the short casing depth by the positioner, verifying the acquired short casing depth according to the short casing depth and length data in the acoustic amplitude logging data after the well completion, calculating the error between the running depth of the coiled tubing and the logging depth, and preliminarily determining the location of the leakage point by the error value; Step S3: According to the preliminary position of the leakage point obtained in step S2, the packer is set by lifting and lowering the coiled tubing, and the check valve is closed at the same time to seal the coiled tubing, and the pressure check is used to reduce leakage and reduce the leakage detection error. After setting, the hanging weight of the monitoring meter returns to 0, and the coiled tubing is pressed down so that the hanging weight range of the monitoring meter is displayed in 20-30kN; Step S4: pressurizing the casing inside the wellhead, and obtaining whether leakage occurs at the current well depth by monitoring the changes in the pressure gauge; Step S5: If the depth monitored in step S4 is not leaking, lift the pipe string to the wellhead and half of the current depth, repeat steps S3 and S4, and cycle in sequence until the leakage point is found; Step S6: After the leakage point is determined, the test is terminated, the casing is depressurized, and the device is disassembled, and the leakage point is subsequently repaired.

[0030] In practical applications, each time the positioner 2 passes a casing coupling, the suspended weight monitored by its monitoring meter increases by 10-20 kN. The number of casing couplings passed is determined by the suspended weight, and the depth of the casing couplings is obtained by the number of casing couplings.

[0031] In this leak detection method, the error value is the difference between the well depth and the logging depth. The initial position of the leakage point is the difference between the well depth and the error value. In actual application, the pressure value of the pressure gauge is stable, indicating that there is no leakage from the wellhead to this depth. If the pressure value of the pressure gauge continues to decrease, it means that leakage occurs in this section.

[0032] There are tens of thousands of leaking wells in Daqing Oilfield, among which more than 2,000 wells have good potential and need to be repaired, fracturing and other subsequent downhole operations. However, there is no process to quickly and accurately find the leakage point and accurately detect the leakage, which makes it impossible to tap the potential of these wells, seriously affecting the production and benefits. The following describes the actual application process of this precise leak detection device based on accurate positioning of the entire wellbore of oil and gas wells: Step 1: Complete the connection of the leak detection device and lower the connected leak detection device to the bottom of the well.

[0033] In this embodiment, the upper end of the guide head 1 is connected to the positioner 2, the positioner 2 is connected to the packer 3, the packer is connected to the check valve 4, and the upper end of the check valve 4 is connected to the coiled tubing 5.

[0034] Step 2: Lift the fracturing string and measure the short casing depth through the locator. Verify the obtained short casing depth according to the short casing depth and length data in the acoustic amplitude logging data after well completion, calculate the error value between the coiled tubing downhole depth and the logging depth, and preliminarily determine the location of the leakage point through the error value.

[0035] In this embodiment, when the pipe string is lifted up and passes through the casing coupling, the raised portion of the positioning sleeve 22 enters the gap between the casing couplings. At this time, the suspended weight displayed on the monitoring meter of the coiled tubing 5 increases. Every time the positioner 2 passes through a casing coupling, the suspended weight increase range monitored by its monitoring meter is 10-20kN. The number of casing couplings passed through is judged by the change in the suspended weight, thereby determining the lowering position of the leak detection device.

[0036] In practical applications, the obtained short casing depth is checked according to the data of short casing depth and length in the acoustic amplitude logging data after well completion, and the error value is calculated. The location of the leakage point is preliminarily determined by the error value.

[0037] Step 3: According to the preliminary location of the leakage point obtained in step 2, the packer is set by lifting and lowering the coiled tubing, and the check valve is closed at the same time to seal the coiled tubing, and the pressure check is used to reduce leakage and reduce the error of leakage detection. After setting, the hanging weight of the monitoring meter returns to 0, and the coiled tubing is pressed down so that the hanging weight range of the monitoring meter is displayed in 20-30 kN.

[0038] In this embodiment, the rubber cylinder 32 is sleeved on the central connecting tube 31, and a cone 35 is installed under the central connecting tube 31. The sealing rubber ring 33 and the gasket 36 are embedded in the cone 35. The packer inner sleeve 38 is sleeved on the central connecting tube 31. The card 36 and the card spring 37 are fixed to the packer inner sleeve 38 through the card sleeve 39. The fixing plate 311 and the fixing leaf spring 312 are embedded in the packer outer sleeve 314 through the packer pin 313. The packer outer sleeve 39 is sleeved on the central connecting tube 31 and is limited by the locking ring 310. In addition, the track pin 316 is embedded in the track sleeve 315 and then embedded in the outer sleeve 39.

[0039] In practical application, the center connecting tube 31 is lifted up and lowered, the track is changed, the card 36 is deployed, the rubber cylinder 32 is seated, and the sleeve is sealed.

[0040] In this embodiment, the sealing ring 42 is installed in the check valve limit sleeve 44, which is inserted into the upper joint 4.1, the T-type packing 47 is inserted into the check valve inner sleeve 45, the pressure cap 49 is pressed on, the pressure ring 48 is tightened, the check valve inner sleeve 45 is threadedly connected to the upper joint 41, and the check valve outer sleeve 46 is threadedly connected to the check valve limit sleeve 44.

[0041] By pressing down the upper joint 41, the T-type packing 47 is driven to the outer sleeve 46 to form a seal, close the check valve 4, and perform pressure check, thereby reducing leakage and narrowing the error of leak detection.

[0042] Step 4: Pressurize the casing inside the wellhead and monitor the changes in the pressure gauge to determine whether there is leakage at the current well depth.

[0043] In actual applications, after the casing is isolated, the casing is pressurized at the wellhead, the well section is tested, and the wellhead pressure gauge is observed to determine the leakage situation of the well section.

[0044] Step 5: If there is no leakage at the depth monitored in step 4, lift the pipe string to half the depth between the wellhead and the current depth, repeat steps 3 and 4, and cycle until the leakage point is found.

[0045] Step 6: After the leak point is determined, end the test, depressurize the casing, disassemble the device, and repair the leak point after the leak point is determined.

[0046] In actual application, after finding the leakage point, the test can be ended and the leak detection device can be disassembled, laying the foundation for subsequent repair work of the leakage point.

[0047] In this embodiment, after the test is completed, the casing is depressurized, the pipe string is lifted up to drive the central connecting pipe 31 to change the track, the card 36 is recovered, and the rubber cylinder 32 is unsealed; at the same time, the lifting of the pipe string drives the upper joint 41 upward, opens the check valve 4, and balances the pressure.

[0048] The device and method for accurate positioning and precise leak detection of the entire wellbore of an oil and gas well provided by the present invention can accurately position and realize continuous and rapid precise leak detection of the entire well, effectively solving the problems of unexplained leakage of the entire wellbore of an oil and gas well, inability to quickly detect leaks, and inability to accurately position and precisely detect leaks.

[0049] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A precise leak detection device for accurate positioning of the entire wellbore of an oil and gas well, characterized in that: include: A guide head (1), the upper end of which is sequentially connected to a positioner (2), a packer (3), a check valve (4) and a coiled tubing (5); The positioner (2) comprises a central tube (21), the outer side of the central tube (21) is fixed to the outer sleeve (22) via a positioner pin (23), a protrusion is provided on the outer side of the positioning outer sleeve (22), and the lower side of the positioning outer sleeve (22) is connected to the positioner limiting sleeve (24) via a thread. The packer (3) comprises a central connecting tube (31), the outer side of the central connecting tube (31) is connected to a rubber sleeve (32), a cone (35), a packer inner sleeve (38), a packer outer sleeve (314) and a track sleeve (315), the rubber sleeve (32) and the cone (35) are connected, the cone (35) and the central connecting tube (31) are sealed by a sealing rubber ring (33), the sealing rubber ring (33) is connected to a gasket (34), the outer side of the packer inner sleeve (38) is connected to a card mechanism, the card mechanism is connected to a fixing plate mechanism via a locking ring (310), the outer side of the fixing plate mechanism is connected to the packer outer sleeve (314), and the bottom end of the card mechanism is connected to the track sleeve (315); The check valve (4) comprises an upper joint (41), the outer side of the upper joint (41) is connected to a check valve limiting sleeve (44), the bottom end of the upper joint (41) is connected to a check valve inner sleeve (45), the outer side of the check valve inner sleeve (45) is connected to a check valve outer sleeve (46), the check valve limiting sleeve (44) is connected to a check valve outer sleeve (46), the outer side of the lower end of the check valve inner sleeve (45) is connected to a T-shaped packing mechanism, and the T-shaped packing mechanism is connected to a pressure ring mechanism.

2. The oil and gas well full wellbore accurate positioning and precise leak detection device according to claim 1 is characterized in that: The card mechanism comprises a card sleeve (39), a card (36) and a card spring (37); the two ends of the card sleeve (39) are respectively a card (36) and a locking ring (310); and the card (36) is provided with a card spring (37).

3. The oil and gas well full wellbore accurate positioning and precise leak detection device according to claim 1 is characterized in that: The fixing plate mechanism comprises a fixing plate (311) and a fixing leaf spring (312); the upper end of the fixing plate (311) is a locking ring (310); two fixing leaf springs (312) are provided on the fixing plate (310); the outer side of the fixing plate (311) is connected to a packer sleeve (314) via a packer pin (313); and the bottom end of the fixing plate (311) is connected to a track sleeve (315) via a track pin (316).

4. The oil and gas well full wellbore accurate positioning and precise leak detection device according to claim 1 is characterized in that: The T-shaped packing mechanism comprises two T-shaped packings (47), and the pressure ring mechanism comprises a pressure ring (48) and a pressure cap (49). The two T-shaped packings (47) are connected, and a pressure ring (48) is provided between the two T-shaped packings (47). The tail end of the T-shaped packing (47) is connected to the pressure cap (49).

5. The oil and gas well full wellbore accurate positioning and precise leak detection device according to claim 4 is characterized in that: The check valve limiting sleeve (44) and the upper joint (41) are sealed via a sealing ring (42); the check valve limiting sleeve (44) is connected to the check valve outer sleeve (46) via a check valve pin (43); and the check valve inner sleeve (45) is connected to the upper joint (41) via the check valve pin (43).

6. The oil and gas well full wellbore accurate positioning and precise leak detection device according to claim 4 is characterized in that: The coiled tubing (5) is provided with a monitoring meter and a counter. The monitoring meter monitors the change of the hanging weight during the running of the coiled tubing into the well in real time, and the counter measures the running depth of the coiled tubing into the well in real time.

7. A method for accurately positioning a precise leak detection device in the entire wellbore of an oil and gas well based on any one of claims 1 to 6, characterized in that: include: Step S1: Complete the connection of the leak detection device and lower the connected leak detection device to the bottom of the well; Step S2: lifting the fracturing string, measuring the short casing depth by the positioner, verifying the acquired short casing depth according to the short casing depth and length data in the acoustic amplitude logging data after the well completion, calculating the error between the running depth of the coiled tubing and the logging depth, and preliminarily determining the location of the leakage point by the error value; Step S3: According to the preliminary position of the leakage point obtained in step S2, the packer is set by lifting and lowering the coiled tubing, and the check valve is closed at the same time to seal the coiled tubing, and the pressure check is used to reduce leakage and reduce the leakage detection error. After setting, the hanging weight of the monitoring meter returns to 0, and the coiled tubing is pressed down so that the hanging weight range of the monitoring meter is displayed in 20-30kN; Step S4: pressurizing the casing inside the wellhead, and obtaining whether leakage occurs at the current well depth by monitoring the changes in the pressure gauge; Step S5: If the depth monitored in step S4 is not leaking, lift the pipe string to the wellhead and half of the current depth, repeat steps S3 and S4, and cycle in sequence until the leakage point is found; Step S6: After the leakage point is determined, the test is terminated, the casing is depressurized, and the device is disassembled, and the leakage point is subsequently repaired.

8. The method for accurate positioning and precise leak detection of the entire wellbore of an oil and gas well according to claim 7 is characterized in that: In step S2, each time the positioner passes through a casing coupling, the suspended weight monitored by the monitoring meter increases in the range of 10-20 kN, and the number of casing couplings passed through is determined by the suspended weight.

9. The method for accurate positioning and precise leak detection of the entire wellbore of an oil and gas well according to claim 7 is characterized in that: In step S2, the error value is the difference between the well depth and the logging depth, and the preliminary position of the leakage point is the difference between the well depth and the error value.

10. The method for accurate positioning and precise leak detection of the entire wellbore of an oil and gas well according to claim 7, characterized in that: In step S5, if the pressure value of the pressure gauge remains stable, it means that there is no leakage from the wellhead to this depth. If the pressure value of the pressure gauge continues to decrease, it means that leakage occurs in this section.

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