Trigger controlled electromagnetic fishing device

Abstract

The application discloses a kind of electromagnetic fishing devices of trigger control, including upper joint, piston, steel ball, shear pin, pressure cap, sealing seat, excitation core, high-energy battery and coupling coil, there are three bypass holes in the middle part of the upper joint, piston is installed in the upper joint and located at the position of bypass hole, shear pin slot is opened on the outer circle of piston, shear pin is threadedly connected on the upper joint, and the end of shear pin is inserted into shear pin slot, and steel ball is sealingly fitted on the upper end of piston.The application can efficiently adsorb fallen objects, has large adsorption force, and the adsorbed objects will not fall off during the tripping process. The magnetic field adsorption force is not affected by the downhole temperature. The adsorbed objects are easy to remove at the well site. The magnetic field disappears after the power coil is powered off, and the adsorbed objects automatically fall off, reducing the labor intensity of workers.

Description

Technical Field

[0001] This invention relates to a trigger-controlled electromagnetic retrieval device, belonging to the field of downhole metal debris retrieval technology. Background Technology

[0002] During drilling in oil and gas field development, the problem of debris falling into the well is common. For example, wrenches, bolts, and large pliers clamps may fall from the wellhead into the well, causing small debris to fall into the well. Also, worn-out roller cones may detach. These loose small debris items must be cleaned up promptly, otherwise, normal drilling will be affected. Electromagnetic retrieval devices utilize their structure to generate an electromagnetic field that attracts and magnetizes small debris and fragments such as individual roller cones, hand-held objects, large pliers jaws, and roller cone teeth, effectively retrieving these small debris items and cleaning the bottom of the well.

[0003] Conventional magnetic retrieval devices such as Figure 2 As shown, it mainly consists of an upper connector 1, a lower connector 22, a permanent magnet 23, a steel ring 24, a copper ring 26, and a flat-bottomed guide shoe 25. Conventional magnetic retrieval devices primarily rely on permanent magnets to magnetize and attract fallen objects, then remove the attracted objects from the wellhead. Permanent magnets are made using two methods: the first is rare-earth sintering, but large-size rare-earth magnets are difficult to process and have high manufacturing costs; the second is magnetizing and strengthening magnetic steel to form a permanent metal magnet. The magnetism of both types of permanent magnets slowly decays over time, and increased temperature increases the rate of magnetic decay. When used at high temperatures downhole, magnetic decay causes a significant decrease in attraction force; moreover, after the magnetic retrieval device attracts metal objects from the wellhead, the metal objects are difficult to remove due to the magnetic attraction force, and the magnet surface is not easy to clean. Summary of the Invention

[0004] The purpose of this invention is to provide a trigger-controlled electromagnetic retrieval device that can solve the problem of magnetic attenuation of permanent magnets and severe reduction in magnetic adsorption force when used in high-temperature wells, reduce the production cost of permanent magnets, and also improve the magnetic adsorption force and the success rate of retrieving objects from the bottom of the well. It has strong adsorption force, good purification of objects from the bottom of the well, and the adsorbed objects will not fall off during the retrieval process, and the adsorbed objects are easy to clean on the ground.

[0005] The technical solution of this invention: A trigger-controlled electromagnetic retrieval device includes an upper connector, a piston, a steel ball, a shear pin, a pressure cap, a sealing seat, an excitation magnet core, a high-energy battery pack, and a coupling coil. Three bypass holes are evenly distributed circumferentially in the middle of the upper connector. A piston is installed inside the upper connector at the position of the bypass holes. A shear pin groove is formed on the outer circumference of the piston. A shear pin is threaded onto the upper connector, with the end of the shear pin inserted into the shear pin groove. A steel ball is sealed at the upper end of the piston. A stepped hole is formed at the lower end of the upper connector, and a sealing seat is installed inside the stepped hole. An excitation magnet core is installed inside the sealing seat. The iron core has a pressure cap threaded to the lower end of the upper connector. At the lower end of the pressure cap, there is an end plate that simultaneously contacts the sealing seat and the end of the excitation core. An upper stepped groove and a lower stepped groove are respectively opened on the outer circle of the excitation core. A high-energy battery pack and a coupling coil are installed in the upper stepped groove and the lower stepped groove, respectively. Two mounting holes are opened at the upper end of the sealing seat. A high-position contact switch and a low-position contact switch are respectively installed in the two mounting holes, and the height of the high-position contact switch is higher than that of the low-position contact switch. The battery pack, coupling coil, high-position contact switch and low-position contact switch are connected to form a circuit by wires.

[0006] Furthermore, the piston has an inner conical hole at its upper end, and the steel ball is disposed in the inner conical hole.

[0007] Furthermore, an annular groove is formed in the inner hole of the piston.

[0008] Furthermore, a wire through hole is provided between the upper step groove and the lower step groove, and the wire passes through the wire through hole.

[0009] Furthermore, sealing rings are installed between the piston and the upper connector, as well as between the sealing seat and the excitation magnet core.

[0010] The advantages of this invention due to the adoption of the above technical solution are as follows: The invention has an ingenious structure, is easy to operate, and can improve magnetic adsorption force and increase the success rate of retrieving objects from the well bottom. This invention can efficiently adsorb fallen objects with a strong adsorption force; the adsorbed object will not fall off during the drilling process; the magnetic field adsorption force is not affected by the downhole temperature; the adsorbed object is easy to remove at the well site; and the magnetic field disappears after the energized coil is de-energized, causing the adsorbed object to fall off automatically, reducing the labor intensity of workers. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of the present invention;

[0012] Figure 2 This is a schematic diagram of a conventional magnetic retrieval device. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0014] Embodiments of the present invention: See Figure 1 The trigger-controlled electromagnetic retrieval device of the present invention includes an upper connector 1, a piston 2, a steel ball 3, a shear pin 4, a pressure cap 5, a sealing seat 6, an excitation core 7, a high-energy battery pack 8, and a coupling coil 9. Three bypass holes 11 are evenly distributed circumferentially in the middle of the upper connector 1. A piston 2 is installed inside the upper connector 1 at the position of the bypass holes 11. A shear pin groove 14 is formed on the outer circumference of the piston 2. A shear pin 4 is threaded onto the upper connector 1, and the end of the shear pin 4 is inserted into the shear pin groove 14. A steel ball 3 is sealed at the upper end of the piston 2. A stepped hole 12 is formed at the lower end of the upper connector 1. A sealing seat 6 is installed in the stepped hole 12, and an excitation core 7 is installed in the sealing seat 6. A pressure cap 5 is threaded to the lower end of the upper connector 1. An end plate 18 is located at the lower end of the pressure cap 5, simultaneously contacting the sealing seat 6 and the end of the excitation core 7. An upper stepped groove and a lower stepped groove are respectively formed on the outer circumference of the excitation core 7. A high-energy battery pack 8 and a coupling coil 9 are respectively installed in the upper and lower stepped grooves. Two mounting holes 19 are formed at the upper end of the sealing seat 6. A high-position contact switch 20 and a low-position contact switch 21 are respectively installed in the two mounting holes 19, with the high-position contact switch 20 being higher than the low-position contact switch 21. The battery pack 8, coupling coil 9, high-position contact switch 20, and low-position contact switch 21 are connected in a circuit via a wire 17. An inner conical hole 15 is provided at the upper end of the piston 2, and a steel ball 3 is disposed in the inner conical hole 15, allowing the steel ball 3 to achieve a seal with the conical surface of the inner conical hole 15. An annular groove 16 is formed in the inner hole of the piston 2, allowing the piston 2 to be removed from the upper connector 1 by hooking the annular groove 16 with a tool, facilitating maintenance. A wire through hole 13 is formed between the upper and lower stepped grooves, through which the wire 17 passes. Sealing rings are installed between the piston 2 and the upper connector 1, as well as between the sealing seat 6 and the excitation magnet core 7, to improve the sealing performance of the device.

[0015] Working principle of this invention:

[0016] First, remove steel ball 3. Connect the retrieval tool to connector 1 via threaded connection and send the electromagnetic retrieval device to the vicinity of the well bottom. Start the mud pump to circulate the mud, which flows through the piston 2 and the inner channel of the exciter core 7 to clean the well bottom. After circulating for a certain period of time, drop steel ball 3 into the wellhead fittings. After steel ball 3 falls into the inner conical hole 15 of piston 2, the mud channel is cut off, and the mud gauge shows an increase in pump pressure. When the pump pressure rises to a certain value, the end of shear pin 4 is sheared by the mud pressure, piston 2 moves downward, and mud flows out through the three bypass holes 11 of connector 1, causing the pump pressure to drop. After piston 2 continues to move downward, it triggers the high-position contact switch 20, and the circuit is connected. The coupling coil 9 generates a high-intensity electromagnetic field, which in turn causes the end face of the exciter core 7 to generate a strong magnetic field adsorption force, efficiently adsorbing metal debris. After the tool is removed from the wellhead, the electromagnetic retrieval device is disassembled, and the steel ball 3 and piston 2 are taken out from the upper part. A long rod is used to trigger the low-position contact switch 21 to disconnect the circuit. The electric field magnetism disappears, causing the adsorbed metal object to fall off automatically. Therefore, this invention can efficiently adsorb fallen objects with a strong adsorption force. The adsorbed object will not fall off during the drilling process. The magnetic field adsorption force is not affected by the downhole temperature. The adsorbed object is easy to remove at the well site. After the coupling coil 9 is de-energized, the magnetic field disappears and the adsorbed object falls off automatically, reducing the labor intensity of workers.

Claims

1. A trigger-controlled electromagnetic retrieval device, comprising an upper connector (1), a piston (2), a steel ball (3), a shear pin (4), a pressure cap (5), a sealing seat (6), an excitation magnet core (7), a high-energy battery pack (8), and a coupling coil (9), characterized in that: Three bypass holes (11) are evenly distributed in the circumferential direction in the middle of the upper connector (1). A piston (2) is installed in the upper connector (1) and at the position of the bypass hole (11). A shear pin groove (14) is opened on the outer circle of the piston (2). A shear pin (4) is threaded on the upper connector (1) and the end of the shear pin (4) is inserted into the shear pin groove (14). A steel ball (3) is sealed and fitted at the upper port of the piston (2). A stepped hole (12) is opened at the lower end of the upper connector (1). A sealing seat (6) is installed in the stepped hole (12). An excitation core (7) is installed in the sealing seat (6). A pressure cap (5) is threaded on the lower end of the upper connector (1). An end plate (18) is provided at the lower end of the pressure cap (5) and simultaneously in close contact with the end of the sealing seat (6) and the end of the excitation core (7). An upper stepped groove and a lower stepped groove are respectively opened on the outer circle of the excitation core (7). A high-energy battery pack (8) and a coupling coil (9) are respectively installed in the upper stepped groove and the lower stepped groove. Two mounting holes (19) are opened at the upper end of the sealing seat (6). A high-position contact switch (20) and a low-position contact switch (21) are respectively installed at the two mounting holes (19). The height of the high-position contact switch (20) is higher than that of the low-position contact switch (21). The battery pack (8), the coupling coil (9), the high-position contact switch (20) and the low-position contact switch (21) are connected to form a circuit through the wire (17). An inner conical hole (15) is provided at the upper end of the piston (2). The steel ball (3) is placed in the inner conical hole (15). An annular groove (16) is opened in the inner hole of the piston (2).

2. The trigger-controlled electromagnetic retrieval device according to claim 1, characterized in that: A wire through hole (13) is provided between the upper step groove and the lower step groove, and the wire (17) passes through the wire through hole (13).

3. The trigger-controlled electromagnetic retrieval device according to claim 1, characterized in that: A sealing ring is installed between the piston (2) and the upper connector (1), as well as between the sealing seat (6) and the excitation magnet core (7).

Images