An electrochemical corrosion-based downhole perforating device, apparatus, method

Abstract

The present application belongs to a kind of downhole perforating device, for the oilfield production pipeline in the prior art, mechanical perforation method cannot be vertically punched, using perforation technology, it can reduce the service life of casing, easily cause blockage to lead to normal production cannot be carried out, and for fractured oil and gas reservoir, whether the hole and fracture meet is difficult to control technical problem, the present application provides a kind of downhole perforating device, equipment and method based on electrochemical corrosion, utilize traction mechanism to send the whole device to the position where it needs to be punched, then through power actuating mechanism, make that main electrode probe and auxiliary electrode probe contact with the wall surface to be punched, then change the potential of main electrode probe and auxiliary electrode probe contact point, utilize potential difference to corrode and induce punching for deep buried downhole narrow pipeline which is difficult to be punched by mechanical method.

Description

Technical Field

[0001] This invention relates to a downhole drilling device, specifically a downhole drilling device, equipment, and method based on electrochemical corrosion. Background Technology

[0002] In oilfield development, downhole pipelines are mostly in the form of casing, meaning the wellbore is separated from the formation by a casing and a cement sheath, as well as a near-wellbore zone contaminated by drilling mud. The main purpose of perforation is to penetrate the casing and cement sheath, open the reservoir, establish communication between the formation and the wellbore, allowing fluids to enter the wellbore and thus enabling normal oil and gas well production. However, perforation technology is only effective for casing and cement sheaths; it cannot be used to perforate production pipelines.

[0003] Because the production pipeline is relatively deep and the pipe diameter is relatively narrow, vertical drilling is not possible during mechanical drilling due to factors such as the large size of the gears.

[0004] If perforation technology is used to perforate the production pipeline, firstly, since the casing has already been perforated, further perforation will reduce the casing's service life; secondly, insufficient energy during perforation may cause bullets or other debris to fall into the annular space between the casing and the production pipeline, causing blockage and preventing normal production. Furthermore, because perforation technology is also involved in drilling and cementing processes, the producing formation is soaked in mud and cement slurry for a long time, making the oil layer susceptible to contamination. The hydrodynamic properties are not perfect at the time of perforation completion, the seepage area of ​​the producing formation is small, and additional seepage resistance is generated near the perforation. Strict requirements are placed on well depth and perforation penetration depth, and high cementing quality is required. For fractured oil and gas reservoirs, due to the uneven development of fractures, the chance of the perforation meeting the fracture is difficult to control. Summary of the Invention

[0005] To address the technical problems in existing oilfield production pipelines, such as the inability to drill vertically using mechanical perforation methods, the reduction of casing life and the potential for blockage leading to production disruptions due to perforation techniques, and the difficulty in controlling whether the borehole meets the fracture in fractured oil and gas reservoirs, this invention provides a downhole drilling device, equipment, and method based on electrochemical corrosion.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A downhole drilling device based on electrochemical corrosion includes a housing, a traction mechanism, a main electrode probe, at least two auxiliary electrode probes, a power unit, a control unit, a pressure detection unit, and a power supply unit.

[0008] The output end of the traction mechanism is connected to the housing and is used to drive the housing to move linearly.

[0009] Both the main electrode probe and the auxiliary electrode probe are installed inside the housing, and the housing has through holes for the main electrode probe and the auxiliary electrode probe to pass through; the output end of the power unit is connected to the main electrode probe and the auxiliary electrode probe to drive the main electrode probe and the auxiliary electrode probe to move linearly; the auxiliary electrode probe is located around the main electrode probe and is evenly arranged along the circumference.

[0010] The pressure detection unit is used to detect the pressure on the main electrode probe and the auxiliary electrode probe;

[0011] The control unit is connected to the power unit, the pressure detection unit, and the power supply unit, respectively. The power supply unit is connected to the main electrode probe and the auxiliary electrode probe, respectively. The control unit is used to send a power setpoint signal to the power unit, receive the pressure detection signal from the pressure detection unit, and control the power supply unit to apply a current signal to the main electrode probe and the auxiliary electrode probe according to the received pressure detection signal.

[0012] Furthermore, it also includes a positioner installed on the housing, with the detection end of the positioner facing outwards from the housing;

[0013] The control unit is connected to the locator and is used to receive the position detection signal from the locator.

[0014] Furthermore, the number of power units and pressure detection units are both two. The power unit includes a main electrode power unit and an auxiliary electrode power unit, and the pressure detection unit includes a main electrode probe pressure sensor and an auxiliary electrode probe pressure sensor.

[0015] The output of the main electrode power unit is connected to the main electrode probe and is used to drive the main electrode probe to move linearly. The output of the auxiliary electrode power unit is connected to each auxiliary electrode probe and is used to drive each auxiliary electrode probe to move linearly synchronously.

[0016] The control unit is connected to the main electrode power unit, the auxiliary electrode power unit, the main electrode probe pressure sensor, and the auxiliary electrode probe pressure sensor, respectively. It is used to send power setpoint signals to the main electrode power unit and the auxiliary electrode power unit, and to receive pressure detection signals from the main electrode probe pressure sensor and the auxiliary electrode probe pressure sensor, respectively.

[0017] Furthermore, it also includes a first mounting base installed within the housing;

[0018] The first mounting base has n first mounting countersunk holes, where n is equal to the sum of the number of main electrode probes and auxiliary electrode probes. All the first mounting countersunk holes are located within the through hole range. The main electrode probe and the auxiliary electrode probe are respectively installed in each first mounting countersunk hole along the axial direction of the first mounting countersunk hole, and the tips of the main electrode probe and the auxiliary electrode probe are both facing the opening end of the first mounting countersunk hole.

[0019] The end face of the first mounting base at the opening of the first mounting countersunk hole is flush with the side wall of the housing.

[0020] Furthermore, both the main electrode power unit and the auxiliary electrode power unit adopt piston motion pairs; both the main electrode power unit and the auxiliary electrode power unit are mounted on the first mounting base and located inside the housing;

[0021] The control unit and the main electrode power unit are connected in sequence via the main electrode probe power setpoint signal line and the main electrode signal converter, and the control unit and the auxiliary electrode power unit are connected in sequence via the auxiliary electrode probe power setpoint signal line and the auxiliary electrode signal converter.

[0022] The control unit is connected to the main electrode probe pressure sensor via the main electrode probe pressure feedback signal line, and is also connected to the auxiliary electrode probe pressure sensor via the auxiliary electrode probe pressure feedback signal line.

[0023] The power supply unit is connected to the main electrode probe via a main electrode probe lead, and is also connected to the auxiliary electrode probe via an auxiliary electrode probe lead.

[0024] The portions of the main electrode probe power setting signal line, auxiliary electrode probe power setting signal line, main electrode probe pressure feedback signal line, auxiliary electrode probe pressure feedback signal line, main electrode probe lead, and auxiliary electrode probe lead located outside the housing are all installed inside a conduit, which is mounted on the housing.

[0025] The inner diameter of the first mounting countersunk hole gradually increases from the opening of the first mounting countersunk hole to the bottom of the first mounting countersunk hole. Sealing elements are provided between the inner wall of the first mounting countersunk hole and the main electrode probe, and between the inner wall of the first mounting countersunk hole and the auxiliary electrode probe.

[0026] Furthermore, the number of power units is one, and the power unit drives the main electrode probe and each auxiliary electrode probe to move synchronously in a linear motion.

[0027] Furthermore, it also includes a second mounting base installed within the housing;

[0028] The output end of the power unit is connected to the second mounting base and is used to drive the second mounting base to move linearly.

[0029] The second mounting base has n second mounting countersunk holes, where n is equal to the sum of the number of main electrode probes and auxiliary electrode probes. All the second mounting countersunk holes are located within the through hole range. The main electrode probe and the auxiliary electrode probe are respectively installed in each second mounting countersunk hole along the axial direction of the second mounting countersunk hole, and the tips of the main electrode probe and the auxiliary electrode probe are both facing the opening end of the second mounting countersunk hole.

[0030] The second mounting base is made of elastic material from the opening of the second mounting countersunk hole to the bottom of the second mounting countersunk hole, forming an elastic protective part. The end face of the elastic protective part at the opening of the second mounting countersunk hole is flush with the side wall of the housing.

[0031] Furthermore, the power unit adopts a piston motion pair, and the power unit is mounted on the second mounting base and located inside the housing;

[0032] The control unit and the power unit are connected in sequence via a power setpoint signal line and a signal converter.

[0033] The control unit and the pressure detection unit are connected via a pressure feedback signal line;

[0034] The power supply unit is connected to the main electrode probe via a main electrode probe lead, and is also connected to the auxiliary electrode probe via an auxiliary electrode probe lead.

[0035] The portions of the power setpoint signal line, pressure feedback signal line, main electrode probe lead, and auxiliary electrode probe lead located outside the housing are all installed inside the conduit, which is mounted on the housing.

[0036] The inner diameter of the second mounting countersunk hole gradually increases from the opening of the second mounting countersunk hole to the bottom of the second mounting countersunk hole. The inner wall of the elastic protection part is provided with a bracket, and a sealing element is provided between the bracket and the main electrode probe and between the bracket and the auxiliary electrode probe.

[0037] Meanwhile, the present invention proposes a downhole drilling device based on electrochemical corrosion, including the aforementioned downhole drilling device based on electrochemical corrosion;

[0038] Each of the aforementioned downhole drilling devices is coaxially arranged.

[0039] In addition, the present invention also provides a downhole drilling method based on electrochemical corrosion, which, based on the above-mentioned downhole drilling device based on electrochemical corrosion, includes the following steps:

[0040] Step 1: The downhole drilling device is sent to the drilling location by a traction mechanism;

[0041] Step 2: The control unit sends a power setting signal to the power unit, causing the power unit to drive the main electrode probe and the auxiliary electrode probe to move. At the same time, the control unit determines whether the tips of the main electrode probe and the auxiliary electrode probe are in contact with the wall of the tube to be pierced based on the pressure detection signal received by the control unit. If they are, step 3 is executed. Otherwise, the power setting signal is continuously sent to the power unit until the tips of the main electrode probe and the auxiliary electrode probe are in contact with the wall of the tube to be pierced.

[0042] Step 3: Through the control unit, keep the power setting value corresponding to the power setting value signal received by the auxiliary electrode probe and the power setting value corresponding to the power setting value signal received by the main electrode probe unchanged; then, through the control unit, apply current signals to the main electrode probe and the auxiliary electrode probe by the power supply unit, and make the potential of the main electrode probe less than the potential of the auxiliary electrode probe; until the current signal of the main electrode probe changes abruptly and the pressure detection value corresponding to the pressure detection signal decreases, the drilling is completed.

[0043] Alternatively, the power setting signal can be adjusted by the control unit to keep the power setting value corresponding to the power setting signal received by the auxiliary electrode probe constant, while gradually increasing the power setting value corresponding to the power setting signal received by the main electrode probe; then the control unit can apply a current signal to the main electrode probe and the auxiliary electrode probe by the power supply unit, and make the potential of the main electrode probe less than that of the auxiliary electrode probe; until the current signal of the main electrode probe changes abruptly and the pressure detection value corresponding to the pressure detection signal decreases, thus completing the drilling.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. This invention employs an appropriate structural design, combined with the principle of electrochemical corrosion, to propose a downhole drilling device based on electrochemical corrosion. It features a simple structure, low cost, and ease of application in actual production. Furthermore, the overall size of this invention is extremely small, facilitating the perforation of narrow, deeply buried downhole pipes. During perforation, it minimizes the risk of damage to narrow pipes, thus significantly reducing the probability of blockage in the annular space between the casing and production pipeline due to pipe damage. This solves the technical problem of difficult perforation of production pipelines during oilfield development.

[0046] 2. This invention proposes two specific downhole drilling device structures, making the invention more widely applicable. Different device structures can be adopted according to the distribution of environmental media. It is applicable whether the medium solution is outside or inside the pipeline. Moreover, neither of the two preferred structures will produce byproducts that block the channel during the drilling process.

[0047] 3. In this invention, a locator is also installed on the housing, which can determine the specific location of the downhole drilling device in the well, ensuring accurate drilling position.

[0048] 4. In the two preferred structures of the present invention, the inner diameter of the countersunk hole opening is smaller than the inner diameter of the bottom of the countersunk hole, which can prevent the external medium solution from corroding the main electrode probe and the auxiliary electrode probe; sealing elements are provided between the first countersunk hole and the corresponding electrode probe, and between the support and the corresponding electrode probe, which can further improve the protection effect on the downhole drilling device; in addition, the guide tube makes it easier to store each lead wire, and when the downhole drilling device is not in use, various leads wires can be tucked away, which helps to save space.

[0049] 5. The present invention also proposes a downhole drilling device based on electrochemical corrosion, which consists of at least two downhole drilling devices coaxially arranged, and can simultaneously drill at different positions along the downhole axis, thereby further improving drilling efficiency.

[0050] 6. Based on the aforementioned downhole drilling device, this invention also proposes a downhole drilling method. The control method is simple, requiring only the control of the setting signal of the power mechanism and the current signals of the main electrode probe and the auxiliary electrode probe to complete the drilling. It is easy to operate and has strong applicability to a wide range of users. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic diagram of an electrochemical corrosion-based downhole drilling device according to the present invention.

[0053] Figure 2 This is a cross-sectional view of Embodiment 1 of the present invention;

[0054] Figure 3 This is a top view of Embodiment 1 of the present invention;

[0055] Figure 4 This is a schematic diagram of the main electrode probe, auxiliary electrode probe, and power mechanism in Embodiment 1 of the present invention;

[0056] Figure 5 This is a cross-sectional view of Embodiment 2 of the present invention;

[0057] Figure 6 Top view for an embodiment of the present invention;

[0058] Figure 7 This is a schematic diagram of the main electrode probe, auxiliary electrode probe, and power mechanism in an embodiment of the present invention.

[0059] Wherein: 1-traction mechanism, 2-auxiliary electrode probe power setting signal line, 3-auxiliary electrode probe pressure feedback signal line, 4-auxiliary electrode probe lead, 5-main electrode probe power setting signal line, 6-main electrode probe pressure feedback signal line, 7-main electrode probe lead, 8-positioning signal line, 9-conduit, 10-housing, 11-first mounting base, 12-auxiliary electrode probe pressure sensor, 13-auxiliary electrode signal converter, 14-main electrode probe pressure sensor, 15-main electrode signal converter, 16-main electrode power unit, 17-auxiliary electrode power unit, 18-seal, 19-main electrode probe, 20-positioner, 21-auxiliary electrode probe, 23-first mounting countersunk hole, 24-elastic protection part, 27-first mounting base, 28-power setting signal line, 29-signal converter, 30-pressure feedback signal line, 31-pressure detection unit, 32-power actuation piston, 33-electrode piston, 34-second mounting base, 35-second mounting countersunk hole. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0061] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0062] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0063] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0064] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0065] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0066] This invention proposes a downhole drilling device based on electrochemical corrosion, comprising a housing 10, a traction mechanism 1, a main electrode probe 19, at least two auxiliary electrode probes 21, a power unit, a control unit, a pressure detection unit 31, and a power supply unit.

[0067] The power supply unit is connected to the main electrode probe 19 and the auxiliary electrode probe 21 respectively, and is used to supply power to the main electrode probe 19 and the auxiliary electrode probe 21.

[0068] The output end of the traction mechanism 1 is connected to the housing 10 and is used to drive the housing 10 to move linearly. When drilling with the downhole drilling device, the traction mechanism 1 can send the device into the well, and after drilling is completed, the device can be lifted out of the well. As a preferred embodiment, the traction mechanism 1 can be implemented by a structure consisting of a traction rope and a gravity hammer, or a structure consisting of a traction rope and a propulsion mechanism. The traction mechanism 1 can also adopt other linear drive structures, as long as they can drive the downhole drilling device to move linearly and achieve lifting and lowering.

[0069] The output of the power unit is connected to the main electrode probe 19 and the auxiliary electrode probe 21, driving their linear motion. Both the main electrode probe 19 and the auxiliary electrode probe 21 are installed inside the housing 10, which provides protection for them. The housing 10 also has through holes for the main electrode probe 19 and the auxiliary electrode probe 21 to pass through. During drilling operations, the main electrode probe 19 and the auxiliary electrode probe 21 extend from the through holes in the housing 10 and contact the wall of the tube to be drilled. The auxiliary electrode probe 21 is located around the main electrode probe 19 and is evenly distributed along its circumference.

[0070] The pressure detection unit is mainly used to detect the pressure on the main electrode probe and the auxiliary electrode probe, and can use existing pressure sensors.

[0071] The control unit is connected to the power unit, pressure detection unit 31, and power supply unit, and is the control terminal of the downhole drilling device. The main functions of the control unit include: (1) sending power setpoint signals to the power unit to control the power setpoints of the main electrode probe 19 and the auxiliary electrode probe 21; (2) receiving pressure detection signals from the pressure detection unit to obtain the pressure conditions of the main electrode probe 19 and the auxiliary electrode probe 21; and (3) controlling the power supply unit to apply current signals to the main electrode probe and the auxiliary electrode probe according to the received pressure detection signals.

[0072] The present invention will be further described below with reference to two preferred embodiments and the accompanying drawings:

[0073] Example 1

[0074] like Figures 1 to 4 As shown, a downhole drilling device based on electrochemical corrosion includes two power units and two pressure detection units. The power unit comprises a main electrode power unit 16 and an auxiliary electrode power unit 17. The pressure detection units include a main electrode probe pressure sensor 14 and an auxiliary electrode probe pressure sensor 12. The auxiliary electrode power unit 17 can contain one or more power sources. All auxiliary electrode probes 21 can share a single power source, or each auxiliary electrode probe 21 can correspond to a separate power source, collectively forming the auxiliary electrode power unit 17. The auxiliary electrode probe pressure sensor 12 is handled similarly.

[0075] The housing can be made of engineering plastic or metal that can withstand temperatures above 300°C. A first mounting base 11 is also provided inside the housing 10. The first mounting base 11 can be made of a non-conductive material that can withstand temperatures above 350°C, such as ceramic. The first mounting base 11 has n first mounting countersunk holes 23, where n is equal to the sum of the number of main electrode probes 19 and auxiliary electrode probes 21. The main electrode probes 19 and auxiliary electrode probes 21 are respectively mounted axially in each of the first mounting countersunk holes 23, with the tips of both the main electrode probes 19 and auxiliary electrode probes 21 facing the opening end of the first mounting countersunk hole 23. The end face of the first mounting base 11 at the opening of the first mounting countersunk hole 23 is flush with the side wall of the housing 10.

[0076] As a preferred embodiment, the main electrode probe 19 and the auxiliary electrode probe 21 can be made of a high-temperature conductive material that can withstand temperatures above 350°C.

[0077] The housing 10 is also equipped with a positioner 20, which can be composed of a fiber optic probe and a water depth hydrostatic pressure device, used to detect the position of the downhole drilling device in the well and ensure accurate drilling position.

[0078] Both the main electrode power unit 16 and the auxiliary electrode power unit 17 are mounted on the first mounting base 11 and located within the housing 10. Both the main electrode power unit 16 and the auxiliary electrode power unit 17 employ a piston-driven mechanism. The output of the main electrode power unit 16 is connected to the main electrode probe 19, driving its linear motion. The output of the auxiliary electrode power unit 17 is connected to each auxiliary electrode probe 21, driving their synchronous linear motion. The control unit is connected to the main electrode power unit 16, the auxiliary electrode power unit 17, the main electrode probe pressure sensor 14, and the auxiliary electrode probe pressure sensor 12, respectively. It sends power setpoint signals to the main electrode power unit 16 and the auxiliary electrode power unit 17, and receives pressure detection signals from the main electrode probe pressure sensor 14 and the auxiliary electrode probe pressure sensor 12. Sealing structures are provided between the first mounting base 11 and the main electrode power unit 16, and between the first mounting base 11 and the auxiliary electrode power unit 17, to protect the device.

[0079] Signal transmission is specifically achieved through the following structure:

[0080] Power setting signal: The control unit and the main electrode power unit 16 are connected in sequence to the main electrode probe power setting signal line 5 and the main electrode signal converter 15. The control unit sends the main electrode probe power setting signal, which is transmitted to the main electrode signal converter 15 via the main electrode probe power setting signal line 5. After conversion, it is sent to the main electrode power unit 16 to drive the main electrode probe. The control unit and the auxiliary electrode power unit 17 are connected in sequence to the auxiliary electrode probe power setting signal line 2 and the auxiliary electrode signal converter 13. The control unit sends the auxiliary electrode probe power setting signal, which is transmitted to the auxiliary electrode signal converter 13 via the auxiliary electrode probe power setting signal line 2. After conversion, it is sent to the auxiliary electrode power unit 17 to drive the auxiliary electrode probe.

[0081] Pressure detection signal: The control unit and the main electrode probe pressure sensor 14 are connected through the main electrode probe pressure feedback signal line 6, and the control unit and the auxiliary electrode probe pressure sensor 12 are connected through the auxiliary electrode probe pressure feedback signal line 2. The corresponding pressure sensors detect the pressure on the main electrode probe 19 and the auxiliary electrode probe 21, and send the signals to the control unit through the main electrode probe pressure feedback signal line 6 and the auxiliary electrode probe pressure feedback signal line 2, respectively, for monitoring the pressure on the main electrode probe 19 and the auxiliary electrode probe 21.

[0082] Current signal: The power supply unit is connected to the main electrode probe 19 via the main electrode probe lead 7, and to the auxiliary electrode probe 21 via the auxiliary electrode probe lead 4, which is used to apply the current of the power supply unit to the main electrode probe 19 and the auxiliary electrode probe 21.

[0083] Position detection signal: The control unit and the locator 20 are connected through the positioning signal line 8. The position detection signal detected by the locator 20 is sent to the control unit through the positioning signal line 8.

[0084] In addition, to facilitate storage and save space, a conduit 9 is installed on the housing 10. The portions of the main electrode probe power setting signal line 5, the auxiliary electrode probe power setting signal line 2, the main electrode probe pressure feedback signal line 6, the auxiliary electrode probe pressure feedback signal line 2, the main electrode probe lead 7, and the auxiliary electrode probe lead 4 located outside the housing 10 are all installed inside the conduit 9.

[0085] Furthermore, to prevent the tips of the main electrode probe 19 and the auxiliary electrode probe 21 from being corroded or damaged, or from foreign objects falling off during the drilling process, the inner diameter of the first mounting countersunk hole 23 gradually increases from the opening to the bottom of the first mounting countersunk hole 23. Sealing elements 18 are provided between the inner wall of the first mounting countersunk hole 23 and the main electrode probe 19, and between the inner wall of the first mounting countersunk hole 23 and the auxiliary electrode probe 21.

[0086] The method for drilling using the device structure of Embodiment 1 is as follows:

[0087] (1) The main body of the downhole drilling device is placed into the downhole drilling pipeline in the oil field by the traction mechanism 1, and the fiber optic image and water depth pressure signal of the positioner 20 confirm that the device has reached the designated position.

[0088] (2) Perform the following operations:

[0089] The control unit issues a power setting signal, which is transmitted to the main electrode power unit 16 via the main electrode probe power setting signal line 5 and the main electrode signal converter 15. Simultaneously, it is transmitted to the auxiliary electrode power unit 17 via the auxiliary electrode probe power setting signal line 2 and the auxiliary electrode signal converter 13, pushing the main electrode probe 19 and the auxiliary electrode probe 21 to extend from the first mounting countersunk hole 23. The pressure on the main electrode probe 19 and the auxiliary electrode probe 21 is detected by the main electrode probe pressure sensor 14 and the auxiliary electrode probe pressure sensor 12, and sent to the control unit via the main electrode probe pressure feedback signal line 6 and the auxiliary electrode probe pressure feedback signal line 2. The pressure feedback signal determines whether the main electrode probe 19 and the auxiliary electrode probe 21 are in contact with the wall surface to be drilled.

[0090] (3) After the main electrode probe 19 and the auxiliary electrode probe 21 come into contact with the wall surface to be drilled, the power setting value of the auxiliary electrode probe 21 is kept unchanged, and the power setting value of the main electrode probe 19 is gradually increased to ensure that the main electrode probe is always in contact with the wall surface of the pipe to be drilled. Then, the power supply unit applies current to the main electrode probe 19 and the auxiliary electrode probe 21 and adjusts the current value of the main electrode probe 19 and the auxiliary electrode probe 21 so that the potential of the main electrode probe 19 is less than the potential of the auxiliary electrode probe 21. By using the potential difference, the corrosion of the contact point of the main electrode probe 19 is accelerated, thereby allowing the pipe to be penetrated.

[0091] (4) When the current signal of the main electrode probe 19 and the feedback signal of the main electrode probe pressure sensor 14 suddenly change, it indicates that the pipeline is penetrated and the main electrode probe 19 is in contact with the medium. Then, the current signals of the main electrode probe 19 and the auxiliary electrode probe 21 are cut off, and the power setting value signals of the main electrode probe 19 and the auxiliary electrode probe 21 are gradually reduced until the main electrode probe 19 and the auxiliary electrode probe 21 are reset. After the feedback signals of the main electrode probe pressure sensor 14 and the auxiliary electrode probe pressure sensor 12 return to normal, the position of the downhole drilling device is changed by the traction mechanism 1 to continue drilling or to remove the downhole drilling device.

[0092] Example 2

[0093] like Figures 5 to 7 As shown, a downhole drilling device based on electrochemical corrosion has one power unit, which drives the main electrode probe 19 and each auxiliary electrode probe 21 to move synchronously in a linear motion. In Embodiment Two, the power unit can also be a piston-moving pair. The power unit is mounted on a second mounting base 34 and located inside the housing 10, driving the second mounting base 34 to move linearly via the principle of the piston-moving pair. The second mounting base 34 is installed inside the housing 10 and is connected to the output end of the power unit, which drives the second mounting base 34 to move linearly.

[0094] The second mounting base 34 has n second mounting countersunk holes 35, where n is equal to the sum of the number of main electrode probes 19 and auxiliary electrode probes 21. All second mounting countersunk holes 35 are located within the through hole range. The main electrode probes 19 and auxiliary electrode probes 21 are respectively installed in each second mounting countersunk hole 35 along the axial direction of the second mounting countersunk hole 35, and the tips of the main electrode probes 19 and auxiliary electrode probes 21 all face the opening end of the second mounting countersunk hole 35.

[0095] The second mounting base 34, from the opening of the second mounting countersunk hole 35 to the bottom of the second mounting countersunk hole 35, is made of elastic material to form an elastic protective part 24. The end face of the elastic protective part 24 at the opening of the second mounting countersunk hole 35 is flush with the side wall of the housing 10. To reduce the deformation of the elastic protective part 24, a bracket can be built into the elastic protective part 24. The bracket and the elastic protective part 24 can be made of plastic, serving to isolate the medium inside the tube from contact with the main electrode probe 19 and the auxiliary electrode probe 21. The bracket can be made of miniature springs or wound wire. Similarly, for protection, the inner diameter of the second mounting countersunk hole 35 gradually increases from the opening of the second mounting countersunk hole 35 to the bottom of the second mounting countersunk hole 35. Sealing elements 18 are provided between the bracket and the main electrode probe 19, and between the bracket and the auxiliary electrode probe 21.

[0096] The signal transmission method is as follows:

[0097] Power setpoint signal: The control unit and the power unit are connected in sequence through power setpoint signal line 28 and signal converter 29. The power setpoint signal is transmitted to the signal converter 29 via power setpoint signal line 28 and then sent to the power unit after conversion.

[0098] Pressure feedback signal: The control unit and the pressure detection unit 31 are connected via a pressure feedback signal line 30. The pressure feedback signal detected by the pressure detection unit 31 is sent to the control unit via the pressure feedback signal line 30.

[0099] Current signal: The power supply unit and the main electrode probe 19 are connected via the main electrode probe lead 7, and the power supply unit and the auxiliary electrode probe 21 are connected via the auxiliary electrode probe lead 4. The power supply unit applies a current signal to the main electrode probe 19 via the main electrode probe lead 7, and applies a current signal to the auxiliary electrode probe 21 via the auxiliary electrode probe lead 4.

[0100] The method for drilling using the device structure of Embodiment 2 is as follows:

[0101] (1) The main body of the downhole drilling device is placed into the downhole drilling pipeline in the oil field by the traction mechanism 1, and the fiber optic image and water depth pressure signal of the positioner 20 confirm that the device has reached the designated position.

[0102] (2) Perform the following operations:

[0103] The control unit issues a power setting signal, which is transmitted to the power unit via the power setting signal line 28. This pushes the second mounting base 34, causing the main electrode probe 19 and the auxiliary electrode probe 21 to extend out of the through hole 3 along with the second mounting base 34. The pressure detection unit 31 detects the pressure on the main electrode probe 19 and the auxiliary electrode probe 21 and sends it to the control unit via the pressure feedback signal line 30. The pressure feedback signal determines whether the main electrode probe 19 and the auxiliary electrode probe 21 are in contact with the wall surface to be drilled.

[0104] (3) After the main electrode probe 19 and the auxiliary electrode probe 21 come into contact with the wall surface to be drilled, the power setting value corresponding to the power setting value signal received by the auxiliary electrode probe 21 and the power setting value corresponding to the power setting value signal received by the main electrode probe 19 are kept unchanged. Then, the power supply unit applies current to the main electrode probe 19 and the auxiliary electrode probe 21 and adjusts the current value of the main electrode probe 19 and the auxiliary electrode probe 21 so that the potential of the main electrode probe 19 is less than the potential of the auxiliary electrode probe 21. By using the potential difference, the corrosion of the contact point of the main electrode probe 19 is accelerated, thereby allowing the pipe to be penetrated.

[0105] (4) When the current signal of the main electrode probe 19 and the feedback signal of the pressure detection unit 31 change abruptly, it indicates that the pipeline has been penetrated. Then, the current signals of the main electrode probe 19 and the auxiliary electrode probe 21 are cut off, and the power setting value signals of the main electrode probe 19 and the auxiliary electrode probe 21 are gradually reduced until the main electrode probe 19 and the auxiliary electrode probe 21 are reset and the feedback signal of the pressure detection unit 31 returns to normal. Then, the position of the downhole drilling device is changed by the traction mechanism 1 to continue drilling or to remove the downhole drilling device.

[0106] The two embodiments described above have different application scenarios. Embodiment 1 is applicable when the medium solution is located inside the pipe, while Embodiment 2 is applicable when the medium solution is located outside the pipe.

[0107] In addition, this invention also provides a downhole drilling device based on electrochemical corrosion, which coaxially combines at least two downhole drilling devices based on electrochemical corrosion, enabling simultaneous drilling at multiple locations. The working principle is the same as the aforementioned downhole drilling device based on electrochemical corrosion.

[0108] The present invention utilizes a traction mechanism 1 and a positioner 20 to ensure that the entire device reaches the position where drilling is required. Then, through a power actuator, the main electrode probe 19 and the auxiliary electrode probe 21 are brought into contact with the wall surface to be drilled. By changing the potential of the contact point between the main electrode probe 19 and the auxiliary electrode probe 21, the potential difference is used to perform corrosion-induced drilling on narrow underground pipes that are difficult to drill mechanically.

[0109] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A downhole drilling device based on electrochemical corrosion, characterized in that: It includes a housing (10), a traction mechanism (1), a main electrode probe (19), at least two auxiliary electrode probes (21), a power unit, a control unit, a pressure detection unit, a power supply unit, and a first mounting base (11) installed inside the housing (10). The output end of the traction mechanism (1) is connected to the housing (10) and is used to drive the housing (10) to move linearly; The main electrode probe (19) and the auxiliary electrode probe (21) are both installed inside the housing (10), and the housing (10) has through holes for the main electrode probe (19) and the auxiliary electrode probe (21) to pass through; the output end of the power unit is connected to the main electrode probe (19) and the auxiliary electrode probe (21) to drive the main electrode probe (19) and the auxiliary electrode probe (21) to move linearly; the auxiliary electrode probe (21) is located around the main electrode probe (19) and is evenly arranged along the circumference; The pressure detection unit is used to detect the pressure on the main electrode probe (19) and the auxiliary electrode probe (21); there are two power units and two pressure detection units. The power unit includes a main electrode power unit (16) and an auxiliary electrode power unit (17). The pressure detection unit includes a main electrode probe pressure sensor (14) and an auxiliary electrode probe pressure sensor (12). The main electrode power unit (16) and the auxiliary electrode power unit (17) both adopt piston motion pairs. The main electrode power unit (16) and the auxiliary electrode power unit (17) are both mounted on the first mounting base (11) and located inside the housing (10). The first mounting base (11) has n first mounting countersunk holes (23), where n is equal to the sum of the number of main electrode probes (19) and auxiliary electrode probes (21). The first mounting countersunk holes (23) are all located within the through hole range. The main electrode probes (19) and auxiliary electrode probes (21) are respectively mounted in each first mounting countersunk hole (23) along the axial direction of the first mounting countersunk hole (23), and the tips of the main electrode probes (19) and auxiliary electrode probes (21) are all facing the opening end of the first mounting countersunk hole (23). The control unit is connected to the power unit, the pressure detection unit and the power supply unit respectively. The power supply unit is connected to the main electrode probe (19) and the auxiliary electrode probe (21) respectively. The control unit is used to send a power setpoint signal to the power unit, receive the pressure detection signal from the pressure detection unit, and control the power supply unit to apply a current signal to the main electrode probe (19) and the auxiliary electrode probe (21) according to the received pressure detection signal. The control unit and the main electrode power unit (16) are connected in sequence via the main electrode probe power setpoint signal line (5) and the main electrode signal converter (15); the control unit and the auxiliary electrode power unit (17) are connected in sequence via the auxiliary electrode probe power setpoint signal line (2) and the auxiliary electrode signal converter (13); the control unit and the main electrode probe pressure sensor (14) are connected via the main electrode probe pressure feedback signal line (6), and the control unit and the auxiliary electrode probe pressure sensor (12) are connected via the auxiliary electrode probe pressure feedback signal line (3); the power supply unit and the main electrode probe (19) are connected via the main electrode probe lead (7), and the power supply unit and the auxiliary electrode probe (21) are connected via the auxiliary electrode probe lead (7). 4) Connected; The portions of the main electrode probe power setting signal line (5), auxiliary electrode probe power setting signal line (2), main electrode probe pressure feedback signal line (6), auxiliary electrode probe pressure feedback signal line (3), main electrode probe lead (7) and auxiliary electrode probe lead (4) located outside the housing (10) are all installed in the conduit (9), and the conduit (9) is installed on the housing (10); The inner diameter of the first mounting countersunk hole (23) gradually increases from the opening of the first mounting countersunk hole (23) to the bottom of the first mounting countersunk hole (23), and a sealing element (18) is provided between the inner wall of the first mounting countersunk hole (23) and the main electrode probe (19), and between the inner wall of the first mounting countersunk hole (23) and the auxiliary electrode probe (21).

2. The downhole drilling device based on electrochemical corrosion according to claim 1, characterized in that: It also includes a positioner (20) mounted on the housing (10), with the detection end of the positioner (20) facing the outside of the housing (10); The control unit is connected to the locator (20) and is used to receive the position detection signal from the locator (20).

3. The downhole drilling device based on electrochemical corrosion according to claim 1 or 2, characterized in that: The output end of the main electrode power unit (16) is connected to the main electrode probe (19) to drive the main electrode probe (19) to move linearly. The output end of the auxiliary electrode power unit (17) is connected to each auxiliary electrode probe (21) to drive each auxiliary electrode probe (21) to move linearly synchronously. The control unit is connected to the main electrode power unit (16), the auxiliary electrode power unit (17), the main electrode probe pressure sensor (14), and the auxiliary electrode probe pressure sensor (12) respectively. It is used to send power setpoint signals to the main electrode power unit (16) and the auxiliary electrode power unit (17), and to receive pressure detection signals from the main electrode probe pressure sensor (14) and the auxiliary electrode probe pressure sensor (12) respectively.

4. The downhole drilling device based on electrochemical corrosion according to claim 3, characterized in that: The end face of the first mounting base (11) at the opening of the first mounting countersunk hole (23) is flush with the side wall of the housing (10).

5. A downhole drilling device based on electrochemical corrosion, characterized in that: Includes at least two of the downhole drilling devices based on electrochemical corrosion as described in any one of claims 1 to 4; Each of the aforementioned downhole drilling devices is coaxially arranged.

6. A downhole drilling method based on electrochemical corrosion, using the downhole drilling apparatus based on electrochemical corrosion as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Step 1: The downhole drilling device is sent to the drilling location by the traction mechanism (1); Step 2: The control unit sends a power setting signal to the power unit, causing the power unit to drive the main electrode probe (19) and the auxiliary electrode probe (21) to move. At the same time, the control unit determines whether the tips of the main electrode probe (19) and the auxiliary electrode probe (21) are in contact with the wall of the tube to be pierced based on the pressure detection signal received by the control unit. If they are, step 3 is executed. Otherwise, the power setting signal is continuously sent to the power unit until the tips of the main electrode probe (19) and the auxiliary electrode probe (21) are in contact with the wall of the tube to be pierced. Step 3: Through the control unit, the power setting value corresponding to the power setting value signal received by the auxiliary electrode probe (21) and the power setting value corresponding to the power setting value signal received by the main electrode probe (19) are kept unchanged; then, through the control unit, the power supply unit applies a current signal to the main electrode probe (19) and the auxiliary electrode probe (21), and makes the potential of the main electrode probe (19) less than the potential of the auxiliary electrode probe (21); until the current signal of the main electrode probe (19) changes abruptly and the pressure detection value corresponding to the pressure detection signal decreases, the drilling is completed; Alternatively, the power setting value signal can be adjusted by the control unit to keep the power setting value corresponding to the power setting value signal received by the auxiliary electrode probe (21) unchanged, and the power setting value corresponding to the power setting value signal received by the main electrode probe (19) can be gradually increased; then the power supply unit can be made to apply a current signal to the main electrode probe (19) and the auxiliary electrode probe (21) by the control unit, and the potential of the main electrode probe (19) can be made to be less than the potential of the auxiliary electrode probe (21); until the current signal of the main electrode probe (19) changes abruptly and the pressure detection value corresponding to the pressure detection signal decreases, the drilling is completed.

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