An electric leak detection and channel detection string and leak detection process

Abstract

The present invention discloses an electric leak detection and crosstalk detection string and leak detection process. The string includes a surface control portion and a downhole leak detection portion connected by a multi-core cable. The multi-core cable and the casing form an oil-casing annulus. The downhole leak detection portion includes an electric packer connected to one end of the multi-core cable, and pressure sensors a and b respectively installed at the upper and lower ends of the electric packer rubber sleeve, with pressure sensors a and b respectively connected to different cable cores of the multi-core cable. The surface control portion includes a cable transmission control mechanism connected to the other end of the multi-core cable for lowering the multi-core cable into or out of the wellbore, an electric packer control terminal for controlling the operation of the electric packer, and a pressure monitoring system for displaying pressure values ​​and / or pressure change graphs. The system can realize intelligent and visual leak detection, shorten leak detection construction time, and improve leak detection efficiency. The use of cables to lower the packer reduces the labor intensity and operating costs of workers.

Description

Technical Field

[0001] The invention belongs to the field of oil production engineering and relates to oil well leak detection technology, in particular to an electric leak detection and channeling detection pipe string and a leak detection process. Background Art

[0002] During the long-term development of oilfields, frequent operations and casing corrosion can lead to casing leakage in oil and water wells. This is particularly true in thermal recovery heavy oil wells, where frequent steam injection and repeated cycles of steam stimulation and puffing cause the casing to expand due to heat. This, combined with thermal stress and geostress, can lead to casing damage, cracking, and leakage. This has led to a growing number of wells with casing leakage and channeling. Once casing leakage occurs in an oil well, not only does it increase the heat loss of injected steam, but it also causes water from the water layer near the damaged or leaking area to flow through, causing a large amount of water to flow back into the oil layer, disrupting normal production and even forcing the well to shut down. This prevents normal water injection into the well, hindering the normal development of the oilfield. To ensure normal production, the damaged and leaking areas of the casing must be plugged or reinforced. To achieve this, it is first necessary to accurately determine whether the casing is leaking and where it is leaking, and then implement appropriate plugging measures.

[0003] Oil well leak detection is a key process throughout oilfield production and a crucial tool for managing high-water-cut leaking wells. The existing technology uses a packer-based leak detection process, which features simple string construction, reliable structure, and low cost, making it a common field leak detection method. Mechanical leak detection strings are often used on-site to verify casing leaks, pinpoint the leak point, and provide a basis for developing a reasonable construction plan. However, the success rate of this method is relatively low, and it takes several trips of tubing to find the leak. The packer is difficult to set, especially in oil wells with severe casing corrosion. At present, the Y521-150 packer is commonly used for leak detection. However, this packer is prone to problems such as difficulty in guiding the guide rail, difficulty in setting the seal, easy damage to the rubber sleeve, and inability of the packer rubber sleeve to effectively seal in oil wells with severe casing corrosion; or when the hanging load of the leak detection tubing is light, the rubber sleeve cannot be expanded, affecting the sealing performance, and it is very easy to misjudge the situation that the packer is not sealed, the oil casing annulus is connected to the oil layer, and the pressure cannot be pumped as a casing leak, resulting in the wrong direction of the plugging measures, thereby leading to a large amount of manpower and material resources.

[0004] At present, the conventional method for leak detection and channel checking is to use an operating machine as a power source, connect the leak detection packer to the bottom of the oil pipe and then send it to the sealing position. After the conventional leak detection packer is mechanically or hydraulically sealed, pressure is applied to the oil pipe or casing by a ground cement truck. Based on the pressure rise and the pressure stability after the pump is stopped, it is determined whether the casing is leaking, and the specific location of the leak is found by repeatedly lifting or lowering the pipe string. The conventional mechanical packer for leak detection and leakage detection needs two to three people to use pipe clamps to rotate the tubing, and the operator cooperates to lower the tubing to seal it. The labor intensity is high, the sealing action is cumbersome, and the sealing time is long. When the casing is corroded in a long section, it is difficult to seal the packer. There are also cases where the packer cannot be sealed after multiple rotations and lowering, which affects the construction period. The conventional hydraulic packer is sealed by pressurizing and unsealed by stopping the pump to release the pressure. When the oil casing pressure is unbalanced, the packer may not be completely unsealed. The tubing is lifted to change the sealing position without fully retracting the rubber cylinder. The packer rubber cylinder is easily damaged, and it is impossible to complete the leak detection of the entire wellbore with one trip of the leak detection tool or tubing. In addition, At some sites, which can only accommodate one water tanker, when the water tanker stops pumping water and changes the water tanker, the hydraulic packer has been unsealed, and the water in the oil casing annulus above the packer leaks into the well section again, causing the water pumped into the oil casing annulus in the previous stage to be in vain; on-site operators count the number of oil pipes, manually measure the length of a single oil pipe and the length of the oil pipe inserted, and the manually calculated depth of the leak point may be inaccurate; the packer is mainly brought in by running the oil pipe, which is labor-intensive; the oil pipe brings the packer in, which takes a long time to raise and lower, and the labor intensity of the workers is high. The oil pipe can easily bring oil and water in the well out of the wellhead, polluting the environment and increasing the cost of oil pollution cleaning and treatment. Summary of the Invention

[0005] In order to overcome the problems of existing leak detection and channeling detection methods, such as the inability to visually see the sealing status of the packer from the ground, the high labor intensity of bringing the oil pipe into the packer and the high labor intensity of setting the packer, the present invention provides a cable-transmitted electric leak detection and channeling detection string and a leak detection process, which can realize intelligent and visual leak detection, thereby shortening the leak detection construction time and improving the leak detection efficiency; the cable is used to lower the packer to reduce the labor intensity and operation cost of the workers.

[0006] The technical solution adopted by the present invention to solve its technical problems is: an electric leak detection and crosstalk detection string, including a ground control part and a downhole leak detection part connected by a multi-core cable, the multi-core cable and the casing forming an oil-casing annulus; the downhole leak detection part includes an electric sealer connected to one end of the multi-core cable, and a pressure sensor a and a pressure sensor b respectively installed at the upper and lower ends of the electric sealer rubber cylinder, the pressure sensor a and the pressure sensor b are respectively connected to different cable cores of the multi-core cable; the ground control part includes a cable transmission control mechanism connected to the other end of the multi-core cable for lowering or pulling the multi-core cable into or out of the wellbore, an electric sealer control terminal for controlling the action of the electric sealer, and a pressure monitoring system for displaying pressure values ​​and / or pressure change diagrams.

[0007] Furthermore, the electric packer adopts dual motors, wherein one motor is connected to and controls the electric packer rubber cylinder, and the other motor is connected to and controls the electric packer slips.

[0008] Furthermore, the pressure monitoring system includes a cable matching circuit module, an amplifier module and an intelligent terminal; the input end of the cable matching circuit module is connected to the multi-core cable, the output end is connected to the input end of the amplifier module, and the output end of the amplifier module is connected to the intelligent terminal.

[0009] Furthermore, the intelligent terminal includes a display submodule, a storage submodule and a data processing submodule; after the signal amplified by the amplification submodule is stored and processed in the storage submodule and the data processing submodule, the pressure value and / or pressure change graph is displayed on the display submodule.

[0010] Furthermore, the cable conveying control mechanism includes a cable winch and a winch controller, the multi-core cable is wound around the cable winch, and the cable winch is connected to the winch controller.

[0011] Furthermore, a cable-specific blowout prevention wellhead is used.

[0012] An electric leak detection process for an electric leak detection and channeling detection string uses the above-mentioned string, adopts the method of casing annulus pressure injection, and monitors the signals of pressure sensors at the upper and lower ends of the electric packer rubber cylinder through a pressure monitoring system to complete the judgment and inspection of the oil well casing leak point.

[0013] Furthermore, the method specifically includes the following steps:

[0014] S1: Use a multi-core cable to lower the electric packer, pressure sensor a, and pressure sensor b to 2-5 meters above the production well section. At this time, the electric packer is in the unsealed state.

[0015] S2: The electric packer control terminal sends a setting command to the electric packer. The dual motors of the electric packer start simultaneously, and the setting of the electric packer cartridge and the slips are completed synchronously. The pressure monitoring system is used to determine whether the electric packer cartridge is effectively sealed. If not, the setting command is repeated.

[0016] S3: After the electric packer is effectively set, a ground cement truck applies pressure to the casing annulus from the wellhead. When the pressure reaches a first predetermined pressure, the pressure is stabilized for a first predetermined length, and the pressure drop in the casing annulus is monitored by the pressure monitoring system. Based on the pressure drop change, it is determined whether the casing above the electric packer is leaking.

[0017] S4: When it is determined that the casing above the electric packer is leaking, the electric packer control terminal sends an unsealing command to the electric packer, and the dual motors of the electric packer are simultaneously started to simultaneously unseal the electric packer rubber cylinder and the slips. Then, the electric packer, pressure sensor a, and pressure sensor b are lifted up to gradually detect leaks in the casing above the electric packer from bottom to top at a predetermined length.

[0018] S5: After the leak point is determined to be within the predetermined range, the electric packer, pressure sensor a, and pressure sensor b are pulled out of the wellhead using a multi-core cable.

[0019] Furthermore, step S2 describes judging whether the electric packer rubber cylinder is effectively sealed by observing the pressure monitoring system, specifically: the pressure monitoring system collects the changes in the resistance values ​​of the pressure sensor a and the pressure sensor b, inversely calculates the pressures at the upper and lower ends of the electric packer rubber cylinder, and determines whether the electric packer is effectively sealed by the pressure difference between the upper and lower ends of the rubber cylinder; when the pressure difference between the upper and lower ends of the rubber cylinder is less than a predetermined value, it is judged that the electric packer is not effectively sealed, and the electric packer is re-sealed or judged to be damaged and removed for replacement.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) An electric packer is used to replace conventional mechanical or hydraulic packers, and an electric packer control terminal is provided. Cable transmission technology is used to quickly realize electric setting and unsealing, replacing the six methods of conventional packers, namely, lifting and lowering the pipe string, rotating the pipe string, self-sealing, hydraulic pressure, lowering tools and thermal pressure. A cable transmission control mechanism is used to lower the electric packer using a multi-core cable instead of the conventional oil pipe to achieve a fast lowering function. The setting of pressure sensors and pressure monitoring systems at the upper and lower ends of the electric packer rubber cylinder realizes the monitoring of the sealing status of the electric packer. The pressure difference range between the upper and lower ends of the rubber cylinder can be used to determine whether the electric packer effectively seals the oil casing and realizes ground visualization and ground intelligent terminal monitoring as well as control of the setting and unsealing of the downhole terminal device.

[0022] (2) The electric packer adopts a dual-motor design, that is, the rubber cylinder and the slip are each controlled by a set of motors, so that the packer rubber cylinder sealing and the slip hanging are carried out synchronously and simultaneously, avoiding the rubber cylinder damage caused by the suspension delay, or the cable being pulled off due to the slip unsealing delay when unsealing and lifting. It is safer and the anchoring action is more reliable. It avoids the situation that the rubber cylinder sealing and the slip hanging actions controlled by a single motor at the same time are easy to interfere with each other, which may cause the slip to fail to be retracted normally, the electric packer stuck in the well and unable to be lifted out, and can only be turned to minor repairs or major repairs, and the slip to fail to stick to the casing normally, the electric packer moves up and down during pressure, and the electric packer rubber cylinder cannot be effectively sealed or damaged. In addition, the use of dual motor control has a smaller motor load, is not easy to burn out, and has better stability. The dual motor greatly reduces the heat generation of the circuit board itself, so that the range of the circuit board controlling the motor suitable for the wellbore ambient temperature is increased from 90° to 110°, which expands the application range of the electric packer, reduces the temperature requirement, and expands the range of well selection.

[0023] (3) The special wellhead for blowout prevention with supporting cable can realize sealing when pressurizing during leak detection process.

[0024] In summary, the present invention solves a series of problems in conventional leak detection and leakage detection methods, such as the inability to visually see the sealing status of the packer on the ground and the high labor intensity of bringing the oil pipe into the packer, and realizes intelligent and visual leak detection, thereby achieving the purpose of shortening the leak detection construction time and improving the leak detection efficiency; reducing the labor intensity and operating costs of workers, reducing the lifting and lowering processes of traditional leak detection and leakage detection tools, and improving the accuracy, comprehensiveness and one-time success rate of leak detection and leakage detection points. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the overall underground and surface structures of the electric leak detection and channeling detection string of the present invention;

[0026] Figure 2 It is a schematic diagram of the overall structure of the electric packer;

[0027] Figure 3 yes Figure 2 An enlarged schematic diagram of the upper part of the structure;

[0028] Figure 4 yes Figure 2 An enlarged schematic diagram of the lower half of the structure;

[0029] Figure 5 This is the leak detection process flow chart of the electric leak detection and channeling detection pipe string;

[0030] Figure 6 This is a simplified diagram of the circuit board structure of the electric packer control terminal.

[0031] Explanation of reference numerals in the figures: 10 - cable winch; 20 - winch controller; 30 - multi-core cable; 40 - pressure sensor a; 50 - electric packer; 60 - pressure sensor b; 70 - cable matching circuit module; 80 - amplifier module; 90 - intelligent terminal; 110 - cable-specific blowout prevention wellhead; 120 - electric packer control terminal; 130 - conversion joint;

[0032] 1-cable core; 2-upper connector; 3-pressure tester; 4-first shear pin; 5-first sealing ring; 6-malachite valve; 7-electronic joint; 8-upper pressure cap; 9-dual motor; 10-first anti-rotation pin; 11-first anti-rotation pin block; 12-connecting sleeve; 13-reducer; 14-second sealing ring; 15-thrust bearing; 16-coupling; 17-lower pressure cap; 18-second anti-rotation pin block; 19-sheath; 20-third sealing ring; 21-anti-rotation sleeve; 22-fourth sealing ring; 23-wire lever; 24-retaining ring; 25-ball. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used solely to distinguish components and should not be construed as indicating or implying relative importance.

[0035] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] Cable transmission technology is currently widely used in the oil industry due to its high tripping and running speeds. Currently, mature technologies include cable-seated bridge plugs, cable logging, and cable production testing. Conventional cable operations can reach tripping and running speeds exceeding 3,000 m / h, with maximum speeds reaching 6,000 m / h, which is 6-12 times the speed of tubing transmission operations. Existing technical solutions for leak detection and channeling all use conventional tubing running, and the packer setting is hydraulically or mechanically performed. This prevents direct observation of the packer's sealing status from the ground, and there are no technologies or applications for cable-based electric leak detection and channeling testing.

[0037] In response to this situation, the present invention proposes the use of an electric packer with a pressure monitoring system, combined with a casing annulus pressure test, to detect leaks in oil well casing. Compared to existing leak detection methods, this method utilizes a pressure monitoring system to observe and monitor the sealing status of the electric packer's rubber sleeve in real time, making it intuitive and efficient. The present invention applies electric packers to leak detection in oil and water wells, making it convenient, fast, and accurate. The construction process is simple, and the detection results are reliable, providing a new method for leak detection in oil and water well casing.

[0038] A cable-transmitted electric leak detection and channeling detection string comprises a ground control part and an underground leak detection part, the two parts are connected by a multi-core cable 30.

[0039] The surface control part includes a cable winch 10, a winch controller 20, a cable matching circuit module 70, an amplifier module 80, an intelligent terminal 90, and an electric packer control terminal 120;

[0040] The downhole leak detection part includes: an electric packer 50, a pressure sensor a40 and a pressure sensor b60.

[0041] The electric packer 50 is located 2-5 meters above the top of the oil layer, and the multi-core cable 30 and the casing form an oil-casing annulus.

[0042] Example 1

[0043] One end of the multi-core cable 30 is connected to one end of a conversion connector 130, the other end of which is connected to the electric packer 50. Pressure sensors a40 and b60 are mounted on the upper and lower ends of the rubber sleeve of the electric packer 50. Pressure sensors a40 and b60 are connected to different cores of the multi-core cable 30 via the conversion connector 130. The multi-core cable 30 is wound around a cable winch 10 located in the wellbore. The winch 10 controls the depth of the electric packer 50, pressure sensors a40, and b60, which are connected to one end of the multi-core cable 30, into the wellbore.

[0044] A winch controller 20 is connected to the cable winch 10. The winch controller 20 controls the cable winch 10 to lower the multi-core cable 30, the conversion joint 130, the electric packer 50, the pressure sensor a40, and the pressure sensor b60 into the wellbore. The pressure in the wellbore determines the resistance value of the pressure sensor a40 and the pressure sensor b60. The ground pressure monitoring system collects the changes in the resistance value and inversely calculates the pressure at the upper and lower ends of the rubber sleeve of the electric packer 50 in the wellbore. The difference in the upper and lower pressures of the rubber sleeve determines whether the electric packer 50 is effectively sealed. When the upper and lower pressure differences are less than a predetermined value, it is determined that the electric packer 50 is not effectively sealed, and the electric packer 50 is re-sealed or it is determined that the electric packer 50 is broken and removed and replaced. The winch controller 20 can be raised and lowered according to user needs to complete leak detection at different well depths.

[0045] The other end of the multi-core cable 30 is connected to the input of the cable matching circuit module 70. The output of the cable matching circuit module 70 is connected to the input of the amplifier module 80. The output of the amplifier module 80 is connected to the intelligent terminal 90. The intelligent terminal 90 mainly includes a display submodule, a storage submodule, and a data processing submodule. After the signal amplified by the amplifier submodule 80 is stored and processed in the storage submodule and the data processing submodule, the pressure value and / or pressure change graph are displayed on the display submodule.

[0046] The other end of the multi-core cable 30 is also connected to the electric packer control terminal 120. The operator can issue a setting command at the electric packer control terminal 120, activating the dual motors of the electric packer 50. The motors rotate forward, axially compressing the rubber sleeve, increasing its diameter and sealing the annulus. Controlled by the other motor, the slips simultaneously open and engage the inner wall of the casing, suspending the string and preventing it from moving upward during pressure injection. Setting is now complete. To release the seal, the operator issues a release command at the electric packer control terminal 120, activating the dual motors and rotating them in the reverse direction. The rubber sleeve and slips retract, completing the release.

[0047] The electric packer control terminal 120 includes a circuit board for controlling dual motors. To accurately control the high-power motors underground from above ground, the circuit board includes a motor drive module, a signal transmission module, and a downhole power supply module, all connected in sequence. This allows the circuit board to accurately control the motors and convert their electrical energy into kinetic energy for setting and releasing the slip seals and cartridges. The circuit board was designed using Altuim Design, the chip control program was developed using IAR, and the host computer software was written in Delphi for a human-computer interaction control system. This implements motor start / stop, rotation, reversing, and speed regulation, meeting the needs of electric leakage detection.

[0048] Example 2

[0049] When the oil well needs to be tested for casing leaks,

[0050] 1. Use appropriate well drilling gauge to drill the well to the oil layer section.

[0051] 2. After the well is cleared, the electric packer 50, pressure sensor a40 and pressure sensor b60 are lowered to 2-5 meters above the production well section using the multi-core cable 30. At this time, the electric packer 50 is in the unsealed state.

[0052] 3. The electric packer control terminal 120 is located in the surface cable car. The electric packer 50 is connected to the electric packer control terminal 120 on the surface via a multi-core cable 30. The operator issues a setting command to the electric packer 50 at the electric packer control terminal 120. The dual motors of the electric packer 50 are activated simultaneously, setting the electric packer 50's rubber cartridge and slips, thereby setting and suspending the tubing string. The operator determines whether the electric packer 50's rubber cartridge is effectively sealed by observing the pressure monitoring system. If not, the setting command is repeated.

[0053] 4. A ground cement truck applies pressure to the casing annulus from the wellhead. When the pressure reaches a first predetermined pressure, the pressure is stabilized for a first predetermined length. The pressure drop in the casing annulus is monitored by a pressure monitoring system. Based on the pressure drop change, it is determined whether the casing above 50 mm of the electric packer is leaking.

[0054] 5. When it is determined that there is a leak in the casing above the electric packer 50, the electric packer control terminal 120 sends an unsealing command to the electric packer 50, and the dual motors of the electric packer 50 are started at the same time, and the unsealing of the rubber cylinder and the slips of the electric packer 50 are completed synchronously. Then the electric packer 50, pressure sensor a40 and pressure sensor b60 are lifted up from bottom to top to gradually check for leaks in the casing above the electric packer 50 at a predetermined length.

[0055] 6. After the leak point is determined to be within the predetermined range, the electric packer 50, pressure sensor a40 and pressure sensor b60 are pulled out of the wellhead using the multi-core cable 30.

[0056] Based on the above scheme, the present invention can achieve rapid and efficient leak detection and channel detection in oil and water wells, while avoiding misjudgment of leak points and improving the accuracy of leak points. The overall leak detection process is simple, efficient, and low-cost. The leak detection operation can be completed in one trip to the leak detection string, solving the following technical problems:

[0057] 1. It solves the problems of high labor intensity and tediousness in setting and releasing the conventional leak detection and channeling packer, which requires rotating and lifting the pipe string or pressurizing and unloading the tubing;

[0058] 2. It solves the problem of long tripping and lowering time due to the oil pipe being carried into the packer, high labor intensity for workers, and the oil pipe easily carrying oil and water out of the wellhead, polluting the environment and increasing the cost of oil pollution cleaning;

[0059] 3. This solves the problem of inaccurate leak depth calculations by operators who manually count the number of oil pipes, measure the length of individual oil pipes, and the length of oil pipes inserted;

[0060] 4. It solves the problem that the sealing status of the packer cannot be visually seen on the ground, which causes uncertainty. For example, if the pressure cannot be tested, it may be that the packer is not sealed effectively, or the oil pipe is leaking, which affects the accuracy of the leak point. It improves the accuracy of leak detection and avoids missed or misjudgment of the leak point.

[0061] This invention can quickly, efficiently, and accurately identify casing leakage, enabling intelligent and visual leak detection, thereby improving leak detection efficiency, reducing labor intensity and operating costs, and simplifying the tripping and untripping process of traditional leak detection and channeling tools. With the increasing number of wells experiencing casing leakage and channeling, this solution has broad application prospects.

[0062] Example 3

[0063] refer to Figure 2-4 The structure of the electric packer 50 is as follows: a male tap 6, an electronic node 7, a dual motor 9, and a reducer 13 are provided in the upper joint 2; a cable core 1 extends into the upper joint 2 and the tail end of the cable core 1 is connected to the male tap 6, the bottom end of the male tap 6 is connected to the electronic node 7, the bottom end of the electronic node 7 is connected to the dual motor 9, and the bottom end of the dual motor 9 is connected to the reducer 13; a first shear pin 4 is provided between the cable core 1 and the male tap 6, and a pressure tester 3 connected to the upper joint 2 is provided at the first shear pin 4; a first sealing ring 5 is provided between the male tap 6 and the upper joint 2;

[0064] The outer wall of the upper joint 2 is sleeved with the upper pressure cap 8, and a first anti-rotation pin 10 is provided between the upper pressure cap 8 and the upper joint 2; the lower end of the upper pressure cap 8 is connected to a connecting sleeve 12 sleeved on the outer wall of the upper joint 2, and a first anti-rotation pin block 11 and a second sealing ring 14 are provided between the connecting sleeve 12 and the upper joint 2;

[0065] A thrust bearing 15, a coupling 16, a sleeve 19 and a wire lever 23 are provided in the connecting sleeve 12; the coupling 16 is connected to the lower end of the reducer 13, and a thrust bearing 15 and a sleeve 19 are provided between the coupling 16 and the connecting sleeve 12. The lower end of the coupling 16 is connected to the wire lever 23, and a third sealing ring 20 is provided between the sleeve 19 and the connecting sleeve 12; a downward pressure cap 17 and an anti-rotation sleeve 21 are provided on the outer wall of the connecting sleeve 12, and a second anti-rotation pin block 18 and a fourth sealing ring 22 are provided between the anti-rotation sleeve 21 and the connecting sleeve 12; a retaining ring 24 is provided between the wire lever 23 and the anti-rotation sleeve 21, and a ball 25 is provided between the retaining ring 24 and the wire lever 23.

[0066] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. An electric leak detection and channeling detection column, characterized in that: The invention comprises a ground control part and a downhole leak detection part which are connected by a multi-core cable (30), wherein the multi-core cable (30) and the casing form an oil-casing annulus; the downhole leak detection part comprises an electric packer (50) connected to one end of the multi-core cable (30), and a pressure sensor a (40) and a pressure sensor b (60) respectively installed at the upper and lower ends of the rubber cylinder of the electric packer (50), wherein the pressure sensor a (40) and the pressure sensor b (60) are respectively connected to different cable cores of the multi-core cable (30); the ground control part comprises a cable transmission control mechanism connected to the other end of the multi-core cable (30) for lowering the multi-core cable (30) into or out of the wellbore, an electric packer control terminal (120) for controlling the action of the electric packer (50), and a pressure monitoring system for displaying a pressure value and / or a pressure change diagram; The electric packer (50) uses dual motors, one of which is connected to and controls the rubber cylinder of the electric packer (50), and the other is connected to and controls the slips of the electric packer (50); The electric leak detection and channeling detection string adopts the casing annulus pressure injection method, and monitors the signals of the pressure sensors at the upper and lower ends of the electric packer (50) rubber cylinder through the pressure monitoring system to complete the judgment and inspection of the oil well casing leak point; specifically, the following steps are included: S1: Using a multi-core cable (30), lower the electric packer (50), pressure sensor a (40) and pressure sensor b (60) to 2-5 meters above the production well section. At this time, the electric packer (50) is in an unsealed state. S2: The electric packer control terminal (120) sends a setting instruction to the electric packer (50), and the dual motors of the electric packer (50) are started simultaneously, and the setting of the rubber cylinder of the electric packer (50) and the setting of the slips are completed synchronously. By observing the pressure monitoring system, it is determined whether the rubber cylinder of the electric packer (50) is effectively sealed. If not, the setting instruction is repeated; S3: After the electric packer (50) is effectively set, a ground cement truck applies pressure to the casing annulus from the wellhead. When the pressure reaches a first predetermined pressure, the pressure is stabilized for a first predetermined length, and a pressure drop change in the casing annulus is monitored by a pressure monitoring system. Based on the pressure drop change, it is determined whether the casing above the electric packer (50) is leaking. S4: When it is determined that the casing above the electric packer (50) is leaking, the electric packer control terminal (120) sends an unsealing instruction to the electric packer (50), and the dual motors of the electric packer (50) are simultaneously started, and the unsealing of the rubber cylinder of the electric packer (50) and the unsealing of the slips are synchronously completed. Then, the electric packer (50), the pressure sensor a (40) and the pressure sensor b (60) are lifted up to gradually detect the leak of the casing above the electric packer (50) from bottom to top by a predetermined length; S5: After the leak point is determined to be within the predetermined range, the electric packer (50), the pressure sensor a (40) and the pressure sensor b (60) are pulled out of the wellhead using the multi-core cable (30).

2. The electric leak detection and cross-flow detection column according to claim 1 is characterized in that: The pressure monitoring system comprises a cable matching circuit module (70), an amplifier module (80) and an intelligent terminal (90); the input end of the cable matching circuit module (70) is connected to the multi-core cable (30), the output end is connected to the input end of the amplifier module (80), and the output end of the amplifier module (80) is connected to the intelligent terminal (90).

3. The electric leak detection and cross-flow detection column according to claim 2, characterized in that: The intelligent terminal (90) comprises a display submodule, a storage submodule and a data processing submodule; after the signal amplified by the amplification submodule (80) is stored and processed in the storage submodule and the data processing submodule, the pressure value and / or the pressure change graph is displayed on the display submodule.

4. The electric leak detection and cross-flow detection column according to claim 1, characterized in that: The cable conveying control mechanism comprises a cable winch (10) and a winch controller (20); a multi-core cable (30) is wound around the cable winch (10); and the cable winch (10) is connected to the winch controller (20).

5. The electric leak detection and cross-flow detection column according to claim 1, characterized in that: A special blowout prevention wellhead (110) for a cable is used.

6. The electric leak detection and cross-flow detection column according to claim 1, characterized in that: In step S2, the electric packer (50) rubber cylinder is judged to be effectively sealed by observing the pressure monitoring system, specifically: the pressure monitoring system collects the change of the resistance value of the pressure sensor a (40) and the pressure sensor b (60), inversely calculates the pressure at the upper and lower ends of the electric packer (50) rubber cylinder, and determines whether the electric packer (50) is effectively sealed by the pressure difference between the upper and lower ends of the rubber cylinder; when the pressure difference between the upper and lower ends of the rubber cylinder is less than a predetermined value, it is judged that the electric packer (50) is not effectively sealed, and the electric packer (50) is re-sealed or it is judged that the electric packer (50) is damaged and is removed and replaced.

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