Mechanical hydraulic jar and jarring method

Abstract

The present invention relates to a jar and a jarring method, and specifically to a mechanical hydraulic jar and a jarring method. The jar comprises an intermediate sleeve, a lower sleeve, a cylinder joint, a cylinder body, and a lower joint arranged below the intermediate sleeve in sequence, a guide core shaft mounted on the guide core shaft, a drive shaft mounted on the top of the drive shaft, an upper joint mounted on the top of the drive shaft; an impact piston and a guide piston are arranged in sequence above the lower joint, a reduced diameter shoulder is arranged on the cylinder body; and hydraulic oil is filled in the cylinder body. The jar can generate three impacts within one stroke of the drill string, and can effectively increase the jarring frequency within a single jarring cycle, thereby effectively increasing the jarring frequency and quickly releasing jams while keeping the stroke frequency unchanged, thereby solving the problem of low jarring frequency and difficulty in quickly releasing jams in existing jars.

Description

Technical Field

[0001] The present invention relates to a jar and a jarring method, and in particular to a mechanical hydraulic jar and a jarring method. Background Art

[0002] Jars are commonly used in underground operations, especially in geologically complex formations. They are typically used for salvaging, coring, and unblocking stuck drill bits and tools during drilling operations. Jars are typically divided into hydraulic and mechanical jars. Mechanical jars convert the kinetic energy of the drill string into a shock by raising or lowering it, while hydraulic jars convert the kinetic energy of the drilling fluid or hydraulic oil into a shock by moving it up and down.

[0003] The patent application with announcement number CN216866635U discloses a downhole operation jar, which includes a support assembly, a jar assembly and a limit assembly. The support assembly includes a shell and multiple limit members. The jar assembly includes a jar hammer, a connecting rod and an impact rod. The limit assembly includes a clamping rod, a sliding block and a support spring. When in use, an external driving member is used to drive the connecting rod upward to lift the drill bit. When the preset force is exceeded, the limit member will be pushed to slide open. At this time, the sliding block rises under the action of the support spring, so that the clamping rod enters the clamping groove of the limit member to lock the position of the limit member, avoiding contact with the connecting rod during vibration to cause wear, thereby improving the service life and facilitating installation and maintenance.

[0004] While the aforementioned jar can deliver a jarring effect, it can only deliver one upward jarring (a jarring) and one downward jarring (a jarring) within a single stroke (the process of lifting and depressing the drill string). This means that the jarring frequency can only be increased by increasing the stroke frequency. When the stroke frequency is limited and cannot be increased, the jarring frequency is low, making it difficult to quickly unblock a stuck drill. Therefore, it is necessary to redesign a mechanical-hydraulic jar and jarring method to address this issue. Summary of the Invention

[0005] The object of the present invention is to provide a mechanical hydraulic jar and a jarring method which can effectively increase the jarring frequency and quickly release jams.

[0006] The technical solution of the present invention is:

[0007] The cam is threadably connected to the upper end of the hydraulic cylinder to form a circular aperture, and the cam is configured to connect the hydraulic cylinder to the oil pump, and the hydraulic cylinder is connected multiple times by a threaded connection to the oil pump end.

[0008] One-way valves with upward flow directions are symmetrically arranged on the guide piston and the impact piston.

[0009] Capillary channels are respectively provided on the circumferential surfaces of the guide piston and the impact piston and on the inner wall of the impact piston.

[0010] The top end of the oil cylinder body is provided with an oil plug.

[0011] The driving shaft is arranged in multiple sections, and adjacent driving shafts are fixedly connected by a locking mechanism; a slip is sleeved on the driving shaft between the locking mechanisms, a slip sleeve is arranged between the upper sleeve and the lower sleeve, and the slip sleeve is connected to the slip.

[0012] The locking mechanism is composed of a locking upper ring, a locking lower ring and a locking bolt. A locking lower ring is arranged below the locking upper ring. The locking lower ring is fixedly connected to the locking upper ring through evenly distributed locking bolts; the locking upper ring and the locking lower ring are respectively threadedly connected to the drive shaft.

[0013] A sealing end cap is threadedly mounted on the top end of the upper sleeve, and the sealing end cap is slidingly and sealingly connected to the drive shaft; a supporting cylinder is threadedly mounted on the upper joint above the sealing end cap.

[0014] The top end surface of the sealing end cover is evenly distributed with driving grooves in a circular shape, and the bottom end surface of the supporting cylinder is provided with driving teeth, which are engaged with the driving grooves.

[0015] The beneficial effects of the present invention are:

[0016] The mechanical hydraulic jar can perform upward and downward strikes when lifting the drill string through the oil cylinder body, the guide piston and the impact piston. The impact of the upper joint on the upper sleeve can be used to perform downward strikes again when lowering the drill string, thereby forming three impacts within one stroke of the drill string. The jar can effectively increase the jarring frequency within a single jarring cycle, thereby effectively increasing the jarring frequency and quickly releasing the jam while keeping the stroke frequency unchanged, thus solving the problem of low jarring frequency of existing jars and being unfavorable for rapid release. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 yes Figure 1 A in the middle is an enlarged schematic diagram;

[0019] Figure 3 1 is a bottom view schematic diagram of the guide piston of the present invention;

[0020] Figure 4 yes Figure 3 The enlarged schematic diagram of point C in the middle;

[0021] Figure 5 is a bottom view schematic diagram of the impact piston of the present invention;

[0022] Figure 6 yes Figure 5 The enlarged schematic diagram of point D in the middle;

[0023] Figure 7 2. It is a schematic structural diagram of the slips of the present invention;

[0024] Figure 8 This is a schematic diagram of the connection of the slips of the present invention;

[0025] Figure 9 yes Figure 1 Schematic diagram of the structure at B in the middle;

[0026] Figure 10 is a bottom view schematic diagram of the locking mechanism of the present invention;

[0027] Figure 11 1 is a schematic top view of the sealing end cover of the present invention;

[0028] Figure 12 It is a structural schematic diagram of the support cylinder of the present invention;

[0029] Figure 13 This is a schematic diagram of the upper striking working state of the present invention;

[0030] Figure 14 It is a schematic diagram of the striking working state of the present invention.

[0031] In the figure: 1. middle sleeve, 2. upper sleeve, 3. lower sleeve, 4. cylinder body, 5. lower joint, 6. guide core shaft, 7. drive shaft, 8. upper joint, 9. cylinder joint, 10. impact piston, 11. guide piston, 12. reducing shoulder, 13. one-way valve, 14. capillary channel, 15. oil plug, 16. slip, 17. slip sleeve, 18. locking upper ring, 19. locking lower ring, 20. locking bolt, 21. sealing end cover, 22. support cylinder, 23. driving groove, 24. driving tooth. DETAILED DESCRIPTION

[0032] The mechanical hydraulic jar consists of an intermediate sleeve 1, an upper sleeve 2, a lower sleeve 3, a cylinder body 4, a lower joint 5, a guide core shaft 6, a drive shaft 7 and an upper joint 8. The top end of the intermediate sleeve 1 is threadedly mounted with the upper sleeve 2, the bottom end of the intermediate sleeve 1 is threadedly mounted with the lower sleeve 3, the lower sleeve 3 is mounted on the cylinder body 4 through the cylinder joint 9, the bottom end of the cylinder body 4 is threadedly mounted with the lower joint 5, and the top end surface of the lower joint 5 is threadedly mounted with the guide core shaft 6. A drive shaft 7 is mounted on the guide mandrel 6. The top end of the drive shaft 7 extends outside the upper sleeve 2. An upper joint 8 is threadedly mounted on the end of the drive shaft 7 extending outside the upper sleeve 2. An impact piston 10 is movably mounted on the guide mandrel 6 above the lower joint 5. A guide piston 11 is mounted on the end of the drive shaft 7 above the impact piston 10. A reduced-diameter shoulder 12 is mounted on the cylinder body 4 above the guide piston 11. The cylinder body 4 is filled with hydraulic oil. The upper joint 8 drives the drive shaft 7 upward when the drill string is raised. It also impacts the upper sleeve 2 during the downward movement of the lower joint 5, creating a downward shock. The function of the guide piston 11 is to promote the flow of hydraulic oil through the guide piston 11 during the process of the upper joint 8 being driven by the drive shaft 7, thereby driving the impact piston 10 to move, so that the impact piston 10 can move upward and then downward to impact the lower joint 5, thereby causing the impact of the impact piston 10 on the lower joint 5 to form a downward shock. On the other hand, during the upward movement of the guide piston 11, it can impact the cylinder joint 9, thereby causing the impact of the guide piston 11 on the cylinder joint 9 to form an upward shock. Through the shock of the upper joint 8 and the upper sleeve 2, the shock of the guide piston 11 and the cylinder joint 9, and the shock of the impact piston 10 and the lower joint 5, three shocks are generated in one stroke of the drill string, thereby effectively increasing the number of shocks in one stroke of the drill string. This can effectively increase the shock frequency without increasing the drill string stroke frequency, so that the jam can be quickly released through rapid multiple shocks, effectively improving the jam release efficiency.

[0033] One-way valves 13 with the flow direction upward are symmetrically arranged on the guide piston 11 and the impact piston 10 respectively. The one-way valve 13 includes a valve body, a valve core, a valve stem and a spring. A central reducing hole is provided on the valve body, and a valve core is inserted in the central reducing hole. Valve stems are symmetrically arranged on the top end surface of the valve core. The valve stem is movably plug-in connected to the guide piston 11 or the impact piston 10, and a spring is mounted on the valve stem; the valve body is threadedly connected to the guide piston 11 or the impact piston 10, and a flow channel is provided on the guide piston 11 or the impact piston 10 between the valve stems. The function of the one-way valve 13 is to allow the hydraulic oil to flow from bottom to top, and to cut off the flow of the hydraulic oil through the one-way valve 13 when the hydraulic oil flows from top to bottom; thus, through the reverse cut-off characteristic of the one-way valve 13, the hydraulic oil below the guide piston 11 and the impact piston 10 can be quickly discharged when the guide piston 11 and the impact piston 10 move downward, thereby avoiding the hydraulic oil below the guide piston 11 and the impact piston 10 from generating a supporting pressure, thereby effectively reducing the downward resistance of the guide piston 11 and the impact piston 10, thereby enabling the guide piston 11 and the impact piston 10 to move downward quickly.

[0034] Capillary channels 14 are respectively provided on the circumferential surfaces of the guide piston 11 and the impact piston 10 and on the inner wall of the impact piston 10. The function of the capillary channels 14 is to enable the hydraulic oil to form a fine flow through the capillary channels 14 during the upward process of the guide piston 11 and the impact piston 10, thereby avoiding excessive negative pressure below the guide piston 11 and the impact piston 10, which seriously affects the upward movement of the guide piston 11 and the impact piston 10, so that the negative pressure generated during the upward movement of the guide piston 11 can drive the impact piston 10 to move upward; on the other hand, it avoids excessive negative pressure to form cavitation damage to the cylinder body 4, the guide piston 11 and the impact piston 10.

[0035] The top end of the oil cylinder body 4 is provided with an oil plug 15 so that when the oil plug is opened, hydraulic oil can be input into the oil cylinder body 4, and after the hydraulic oil input is completed, the oil plug 15 can be used to seal the oil cylinder body 4.

[0036] The drive shaft 7 is arranged in multiple sections, with adjacent drive shafts 7 fixedly connected by a locking mechanism. Slips 16 are mounted on the drive shafts 7 between the locking mechanisms. The slips 16 include a support seat and an elastic rod. The support seat is cylindrical, with multiple elastic rods spaced apart on the top end of the support seat. The outer end surfaces of the elastic rods are provided with latching teeth. A slip sleeve 17 is disposed between the upper sleeve 2 and the lower sleeve 3. The slip sleeve 17 is cylindrical, with a latching groove on its inner wall. The latching groove engages with the latching teeth, allowing the slip sleeve 17 to engage with the slips 16. The locking mechanism not only connects the drive shafts 7 but also supports the slips 16 through the locking mechanism, securing them to the drive shaft 7 so that they can move with the drive shaft 7 when the drive shaft 7 moves. The elasticity of the elastic rod of the slip 16 is preset. When the extrusion force on the elastic rod formed by the interaction force between the latching teeth and the latching groove exceeds the preset elastic force value of the elastic rod, the elastic rod is forced to bend toward the drive shaft 7, so that the latching teeth and the latching groove are disengaged, thereby disengaging the slip 16 and the slip sleeve 17, allowing the drive shaft 7 to move upward.

[0037] The locking mechanism is composed of a locking upper ring 18, a locking lower ring 19 and a locking bolt 20. A locking lower ring 19 is provided below the locking upper ring 18, and the locking lower ring 19 is fixedly connected to the locking upper ring 18 by evenly distributed locking bolts 20; the locking upper ring 18 and the locking lower ring 19 are respectively threadedly connected to the drive shaft 7. Specifically, the locking upper ring 18 is threadedly connected to the drive shaft 7 at the upper end, and the locking lower ring 19 is threadedly connected to the drive shaft 7 at the lower end. Therefore, in the process of locking the locking upper ring 18 and the locking lower ring 19 with the locking bolt 20, the mutually locked locking upper ring 18 and the locking lower ring 19 can lock the respectively connected drive shafts 7, so that the upper and lower sections of the drive shaft 7 are fixedly connected.

[0038] A sealing end cap 21 is threadedly mounted on the top end of the upper sleeve 2, which is in sliding, sealing engagement with the drive shaft 7. A support tube 22 is threadedly mounted on the upper connector 8 above the sealing end cap 21. The sealing end cap 21 not only seals the top end of the upper sleeve 2, but also acts as a force-bearing surface to withstand impact from the support tube 22 as the upper connector 8 drives it downward. This allows the upper connector 8 to impact the upper sleeve 2 via the support tube 22 and sealing end cap 21 during its downward motion.

[0039] The top end surface of the sealing end cap 21 is uniformly distributed with drive grooves 23 in an annular shape, and the bottom end surface of the support tube 22 is provided with drive teeth 24, which engage with the drive grooves 23. The function of the drive teeth 24 is to enable the sealing end cap 21 to engage with the support tube 22, so that when the upper joint 8 drives the support tube 22 to rotate, the support tube 22 can drive the sealing end cap 21 to rotate through the cooperation of the drive teeth 24 and the drive grooves 23, thereby transmitting torque to the sealing end cap 21, so that the sealing end cap 21 can drive the lower joint 5 to rotate in sequence through the upper sleeve 2, the intermediate sleeve 1, the lower sleeve 3, the cylinder joint 9, and the cylinder body 4, thereby transmitting torque when the downhole tool is operating normally, driving the downhole tool to rotate normally.

[0040] The jarring method of the mechanical hydraulic jar comprises the following steps:

[0041] After the downhole tool becomes stuck at the bottom of the well, the drill string is lifted, and the upper joint 8 is pulled upward through the drill string. The upper joint 8 transmits the tension applied by the drill string to the drive shaft 7. When the tension exerted by the drill string on the drive shaft 7 through the upper joint 8 exceeds the preset elastic force of the elastic rod of the slips 16, the slips 16 and the slip sleeves 17 are unstuck, and the drill string drives the drive shaft 7 upward through the upper joint 8. As the drive shaft 7 moves upward, the drive shaft 7 drives the guide piston 11 at the bottom end of the drive shaft 7 upward. During the rapid upward movement of the guide piston 11, negative pressure is generated below the guide piston 11. The impact piston 10 is pushed upward by the hydraulic oil below the impact piston 10 and the negative pressure above the impact piston 10. When the guide piston 11 moves upward to the bottom end surface and exceeds the reduced diameter shoulder 12, the inner wall of the cylinder body 4 expands outward, and a large circulation channel is formed between the cylinder body 4 and the guide piston 11. Under the action of the circulation channel between the cylinder body 4 and the guide piston 11, on the one hand, the upward resistance of the guide piston 11 is reduced, so that the guide piston 11 can move upward quickly, and then the cylinder joint 9 is shocked by the rapidly moving guide piston 11; on the other hand, the guide piston 11 squeezes the hydraulic oil above the guide piston 11 during the rapid upward process, so that the hydraulic oil flows rapidly downward through the circulation channel between the cylinder body 4 and the guide piston 11, rapidly increasing the pressure of the hydraulic oil above the impact piston 10. At the same time, due to the upward movement of the impact piston 10, the pressure of the hydraulic oil below the impact piston 10 is reduced, so that a large pressure difference is formed between the upper and lower parts of the impact piston 10, which pushes the impact piston 10 downward, causing the impact piston 10 to impact the lower joint 5 downward, thereby shocking the lower joint 5 downward. After the guide piston 11 ascends until it contacts the cylinder joint 9, the drill string is lowered, which in turn drives the support tube 22 and drive shaft 7 downward through the upper joint 8. As the drive shaft 7 descends, it pushes the guide piston 11 downward to reset. During this downward movement, the one-way valve 13 reduces the downward resistance of the guide piston 11, allowing it to descend rapidly, thereby rapidly descending the drive shaft 7, upper joint 8, and support tube 22. During this rapid downward movement, the support tube 22 impacts the sealing end cap 21, causing a shock.

[0042] The mechanical hydraulic jar can perform upward and downward strikes when lifting the drill string through the oil cylinder body 4, the guide piston 11 and the impact piston 10. The impact of the upper joint 8 on the upper sleeve 2 can perform downward strikes again when lowering the drill string, thereby forming three impacts within one stroke of the drill string. The jar can effectively increase the jarring frequency within a single jarring cycle, thereby effectively increasing the jarring frequency and quickly releasing the jam under the condition that the stroke frequency remains unchanged, thereby solving the problem of low jarring frequency of existing jars and being unfavorable for rapid release.

Claims

1. A mechanical hydraulic jar, comprising an intermediate sleeve (1), an upper sleeve (2), a lower sleeve (3), a cylinder body (4), a lower joint (5), a guide core shaft (6), a drive shaft (7) and an upper joint (8), characterized in that: The top end of the intermediate sleeve (1) is threadedly mounted with an upper sleeve (2), the bottom end of the intermediate sleeve (1) is threadedly mounted with a lower sleeve (3), an oil cylinder body (4) is mounted on the lower sleeve (3) through an oil cylinder joint (9), a lower joint (5) is threadedly mounted on the bottom end of the oil cylinder body (4), a guide core shaft (6) is threadedly mounted on the top end face of the lower joint (5), a drive shaft (7) is sleeved on the guide core shaft (6), the top end of the drive shaft (7) extends to the outside of the upper sleeve (2), and an upper joint (8) is threadedly mounted on the end of the drive shaft (7) extending to the outside of the upper sleeve (2); an impact piston (10) is movably sleeved on the guide core shaft (6) above the lower joint (5), a guide piston (11) is provided on the end of the drive shaft (7) above the impact piston (10), and a reduced diameter shoulder (12) is provided on the oil cylinder body (4) above the guide piston (11); the oil cylinder body (4) is filled with hydraulic oil; The guide piston (11) and the impact piston (10) are symmetrically provided with a one-way valve (13) with an upward flow direction; The top end of the upper sleeve (2) is threadedly mounted with a sealing end cover (21), which is in sliding sealing connection with the drive shaft (7); and the upper joint (8) above the sealing end cover (21) is threadedly mounted with a support cylinder (22).

2. A mechanical hydraulic jar according to claim 1, characterized in that: Capillary channels (14) are respectively provided on the circumferential surfaces of the guide piston (11) and the impact piston (10), as well as on the inner wall of the impact piston (10).

3. The mechanical hydraulic jar according to claim 1, characterized in that: The top end of the oil cylinder body (4) is provided with an oil plug (15).

4. The mechanical hydraulic jar according to claim 1, characterized in that: The drive shaft (7) is arranged in multiple sections, and adjacent drive shafts (7) are fixedly connected by a locking mechanism; a slip (16) is sleeved on the drive shaft (7) between the locking mechanisms, a slip sleeve (17) is arranged between the upper sleeve (2) and the lower sleeve (3), and the slip sleeve (17) is clamped with the slip (16).

5. A mechanical hydraulic jar according to claim 4, characterized in that: The locking mechanism is composed of a locking upper ring (18), a locking lower ring (19) and a locking bolt (20). A locking lower ring (19) is provided below the locking upper ring (18). The locking lower ring (19) is fixedly connected to the locking upper ring (18) through locking bolts (20) that are evenly distributed. The locking upper ring (18) and the locking lower ring (19) are respectively threadedly connected to the drive shaft (7).

6. The mechanical hydraulic jar according to claim 1, characterized in that: The top end surface of the sealing end cover (21) is uniformly distributed with driving grooves (23) in a circular shape, and the bottom end surface of the support cylinder (22) is provided with driving teeth (24), which are engaged with the driving grooves (23).

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