Sealed following type hydraulic jar

Abstract

The invention discloses a sealed following type hydraulic jar, and relates to the field of hydraulic jarring, the sealed following type hydraulic jar comprises a barrel, a drill column and a connector, a hydraulic cylinder is arranged in the barrel, an impact rod is arranged in the hydraulic cylinder in a sliding manner, an impact seat matched with the impact rod is arranged in the drill column, and the connector is connected with the hydraulic cylinder. An upper sleeve shell and a lower sleeve shell are fixedly connected between the impact rod and the hydraulic cylinder, second sealing rubber pads are arranged in the upper sleeve shell and the lower sleeve shell, and a first sealing rubber pad is installed on the outer wall of the impact rod. The pressure of an upper cavity starts to rise, meanwhile, in the upward sliding process of an impact rod, an arc-shaped sealing block on the outer wall can rigidly seal a hydraulic cylinder, in the upward sliding process of the impact rod, a first sealing rubber mat and a second sealing rubber mat are in a staggered state, and in the process, damage of high pressure to the two sealing rubber mats can be greatly reduced; and meanwhile, the first sealing rubber mat can slide into the open groove, and the situation that the two sealing rubber mats are excessively deformed due to excessive extrusion of the follow-up impact rod is prevented.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic jars, in particular to a sealed follower type hydraulic jar. Background Art

[0002] A hydraulic jar is a downhole tool that uses a hydraulic system to control the impact force. It is mainly used to resolve stuck drill accidents during oil drilling and well repair operations. It is also widely used in construction machinery, mining equipment and other fields. Its core principle is to convert the elastic potential energy stored in the drill string into instantaneous impact force through the pressure change and delayed release mechanism of hydraulic oil, thereby achieving efficient jam relief.

[0003] When the existing hydraulic jar is actually working, when the drill bit at the output end encounters resistance and needs to be unstuck, the drill string is lifted, causing the impact of the jar to move upward. As the lifting force of the big hook continues to increase, the drilling tool is lifted to generate high pressure inside the hydraulic chamber. During the delay stage, the hydraulic oil slowly flows through the tiny flow channel. After the energy accumulates to the critical point, it is released instantly, pushing the core shaft to move at high speed to produce impact. At this time, the jar is slowly pulled open under the action of pre-tension and hydraulic resistance. After that, the damping control valve is opened, and the hydraulic oil loses resistance and impacts the impact seat at the top. At this time, the jar enters a free impact state, and quickly slides to the extreme position within a fixed stroke. The impact mechanism strikes, generating a strong upward impact force, thereby realizing the function of unstuck.

[0004] During the actual operation of the above structure, the impact rod and the hydraulic cylinder are sealed by a sealing rubber gasket. Since the drill may be stuck many times during the drilling process, the sealing rubber gasket can complete the sealing work under normal pressure after sliding multiple times. However, when the jam needs to be released, when the upper chamber of the hydraulic cylinder is under high pressure, the pressure of the hydraulic oil is very likely to be discharged from the gap of the sealing gasket, resulting in leakage of the hydraulic oil. The leakage of the hydraulic oil will reduce the high pressure in the upper chamber, affecting the subsequent vibration force between the impact rod and the impact seat, thereby affecting the subsequent unjamming effect of the drill bit and reducing the overall service life of the device. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a sealed follow-up hydraulic jar to solve the problem that the sealing gasket under high pressure will cause leakage of hydraulic oil, and the leakage of hydraulic oil will reduce the high pressure in the upper chamber, affecting the subsequent vibration force between the impact rod and the impact seat, thereby affecting the subsequent unjamming effect of the drill bit. Technical problem.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a sealed follow-up hydraulic jar, comprising a cylinder, a drill string, and a connector, wherein the upper end of the cylinder is elastically connected to the drill string, and the lower end is connected to the connector, a hydraulic cylinder is disposed inside the cylinder, wherein an impact rod is slidably disposed inside the hydraulic cylinder, an impact seat is disposed inside the drill string and cooperates with the impact rod, and an upper shell and a lower shell are fixedly connected between the impact rod and the hydraulic cylinder; A second sealing rubber pad is provided in both the upper shell and the lower shell, a first sealing rubber pad is installed on the outer wall of the impact rod, and an arc-shaped sealing block is also provided on the impact rod at the bottom of the first sealing rubber pad, wherein the top of the arc-shaped sealing block is rigidly sealed with the upper shell and the lower shell respectively.

[0007] By adopting the above technical solution, the pressure in the upper chamber begins to increase. At the same time, the arc-shaped sealing block on the outer wall will rigidly seal the hydraulic cylinder during the upward sliding of the impact rod, thereby ensuring the pressure in the upper chamber under high pressure. During the upward sliding of the impact rod, the first sealing gasket will be driven to slide, so that the first sealing gasket and the second sealing gasket are in a dislocated state. In this process, the damage to the two sets of sealing gaskets caused by high pressure will be reduced. At the same time, the first sealing gasket will slide into the groove to prevent the subsequent impact rod from excessively squeezing the two sets of sealing gaskets and causing excessive deformation, thereby ensuring the sealing effect between the two subsequent sets of sealing gaskets.

[0008] The present invention is further configured such that a fixing plate is provided on the top of the impact rod, wherein a pulling plate cooperating with the fixing plate is provided inside the drill string.

[0009] Preferably, during the process of lifting the drill string, the pull plate will move upward along with the drill string. When the top of the pull plate contacts the bottom of the fixed plate, the two are in a limited state. As the drill string continues to slide upward, the impact rod is driven to slide upward through the cooperation of the fixed plate and the pull plate.

[0010] The present invention is further configured such that a piston is slidingly arranged in the hydraulic cylinder, wherein the piston is located on the outer wall of the impact rod, and under the action of the piston, the hydraulic cylinder is divided into an upper chamber and a lower chamber, and a pressure relief pipe and an oil return pipe are respectively arranged in the cylinder interlayer at the hydraulic cylinder, wherein a damping control valve is arranged in the pressure relief pipe and the oil return pipe, and the two ends of the pressure relief pipe and the oil return pipe are respectively connected to the upper chamber and the lower chamber.

[0011] Preferably, during the process of the impact rod sliding upward through the drill string, the piston will slide upward in the hydraulic cylinder. During this process, the piston squeezes the space in the upper chamber. During this process, the hydraulic oil in the upper chamber is compressed. Due to the flow limiting of the damping control valve, the hydraulic oil cannot flow quickly to the lower chamber, which will cause the pressure in the upper chamber to begin to rise. After the subsequent impact rod completes the shock to the impact seat, it will slide downward under the action of the elastic component and the impact rod's own gravity. At this time, the damping control valve in the return oil pipe opens, allowing the hydraulic oil to flow back to the upper chamber, and its piston returns to its initial position, waiting for the next lifting cycle.

[0012] The present invention is further configured such that an oil storage chamber is provided in the cylinder at the bottom of the hydraulic cylinder, and an oil suction pipe and an oil discharge pipe are respectively connected between the oil storage chamber and the lower chamber, wherein both the oil suction pipe and the oil discharge pipe are provided with an electrically controlled one-way valve.

[0013] Preferably, during the process of the piston sliding upward through the impact rod, a certain cavity will be generated in its lower chamber. At this time, the hydraulic oil in the oil storage chamber is extracted into the lower chamber through the oil extraction pipe to avoid cavitation and ensure that the pressure in the lower chamber is within a certain range. Subsequently, the hydraulic oil in the upper chamber is discharged into the lower chamber through the damping control valve. After the impact on the piston is completed, part of the hydraulic oil will be discharged back into the oil storage chamber through the oil drain pipe for subsequent continued use.

[0014] The present invention is further configured such that an energy storage component is provided on the top of the hydraulic cylinder, and the energy storage component itself is detachably provided.

[0015] Preferably, the energy storage assembly can absorb some pressure fluctuations, thereby avoiding a sudden increase in upper chamber pressure that may damage the seal and increasing the overall service life.

[0016] The present invention is further configured such that a groove is provided in both the upper shell and the lower shell, wherein the groove is located at the top of the second sealing gasket.

[0017] Preferably, the first sealing rubber pad will slide into the groove following the impact rod to prevent the subsequent impact rod from over-extruding and causing excessive deformation of the two sets of sealing rubber pads, thereby ensuring the sealing effect between the subsequent two sets of sealing rubber pads. At the same time, during the impact of the impact rod, the slot setting prevents the first sealing rubber pad from absorbing part of the impact force, thereby ensuring that the impact force is stably transmitted to the drill bit at the bottom.

[0018] The present invention is further configured such that the drill string and the barrel are arranged in a clamping manner, and an elastic component is connected between the drill string and the barrel.

[0019] Preferably, during the process of lifting the drill string, the elastic component inside it is in a stretched state, and when it continues to slide, it will lift the internal impact rod. After the subsequent impact rod completes the shock, the impact rod will drive the piston to slide downward under the action of the reset force of the elastic component and the impact rod's own gravity.

[0020] The present invention is further configured such that the connector and the cylinder are welded, and an outer wall of the connector is provided with an external thread.

[0021] Preferably, the welding setting ensures that the drill bit can provide stable drilling force during the driving process, and the external thread setting ensures that the drill bit can be disassembled, which facilitates subsequent maintenance and replacement, thereby increasing the overall service life of the device.

[0022] The present invention is further configured such that the energy storage assembly includes a bladder accumulator and a frame, wherein the frame is located at the top of the hydraulic cylinder, and a bladder accumulator is provided on the frame, and the bladder accumulator is filled with nitrogen.

[0023] Preferably, nitrogen is filled in the bladder accumulator with a pre-charge pressure of 10 MPa. When the pressure in the upper chamber gradually increases, when the pressure exceeds the nitrogen pre-charge pressure, the bladder accumulator automatically contracts. At this time, the hydraulic oil in the accumulator is pressurized synchronously with the upper chamber, which is equivalent to expanding the energy storage space of the upper chamber and preventing the cylinder from being cracked by excessive pressure.

[0024] The present invention is further configured such that the outer wall of the lower housing and the inner wall of the oil storage cavity are configured to be smooth.

[0025] Preferably, the smooth configuration facilitates stable flow of the hydraulic oil inside and prevents the hydraulic oil from agglomerating into lumps on the inner wall.

[0026] In summary, the present invention mainly has the following beneficial effects: The present invention connects the inner walls of the upper shell and the lower shell with second sealing rubber gaskets respectively. Under normal pressure, the hydraulic cylinder is sealed by cooperating with the first sealing rubber gasket. When the impact rod moves upward through the drill string, the piston slides upward in the hydraulic cylinder. At this time, the hydraulic oil in the upper chamber is compressed. Due to the flow restriction of the damping control valve, the oil cannot flow to the lower chamber quickly, thereby causing the pressure in the upper chamber to begin to increase. At the same time, during the upward sliding of the impact rod, the arc-shaped sealing block on the outer wall rigidly seals the hydraulic cylinder, thereby ensuring the pressure in the upper chamber under high pressure and improving the shock effect of the subsequent impact rod. The present invention arranges the first sealing rubber gasket on the impact rod, and the second sealing rubber gasket is respectively located in the upper shell and the lower shell. When the impact rod slides upward, the first sealing rubber gasket is driven to slide, so that the first sealing rubber gasket and the second sealing rubber gasket are in a dislocated state. In this process, the damage of the two sets of sealing rubber gaskets to the high pressure is greatly reduced. At the same time, the first sealing rubber gasket slides into the groove, preventing the subsequent impact rod from excessively squeezing the two sets of sealing rubber gaskets so as to prevent excessive deformation of the two sets of sealing rubber gaskets. The sealing effect between the two sets of sealing rubber gaskets is ensured, thereby extending the service life of the entire device. The present invention arranges grooves in the upper shell and the lower shell on the upper part of the first sealing gasket. When the subsequent damping control valve is fully opened to release pressure, the impact rod itself will slide upward. During this process, the first sealing gasket and the second sealing gasket cooperate with each other to make the impact rod in flexible contact with the upper shell and the lower shell respectively, effectively preventing them from rigid wear, and ensuring that the arc-shaped sealing block still has a certain sealing performance for the hydraulic cylinder during multiple impact sliding processes. Moreover, when the impact rod contacts the impact seat, the groove setting prevents the first sealing gasket from absorbing part of the shock force, thereby ensuring that the shock force is stably transmitted to the drill bit at the bottom. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A perspective view of the present invention; Figure 2 This is a schematic structural diagram of the impact rod of the present invention in a normal state; Figure 3 It is a schematic structural diagram of the impact seat of the present invention; Figure 4 For the present invention Figure 2 A magnified view of middle A; Figure 5 For the present invention Figure 2 Enlarged view of middle B; Figure 6 It is an interior view of the cylinder and the impact rod of the present invention; Figure 7 It is a cross-sectional view of the cylinder of the present invention; Figure 8 For the present invention Figure 7 Enlarged view of middle C; Figure 9 This is a schematic structural diagram of the impact rod and hydraulic assembly of the present invention; Figure 10 It is a schematic diagram of the impact rod structure of the present invention; Figure 11 Schematic diagram of the flow channel structure of the damping control valve of the present invention; Figure 12 It is a structural schematic diagram of the impact rod of the present invention in the delayed state.

[0028] Description of reference numerals: 1. Cylinder; 2. Drill string; 3. Connector; 4. Impact seat; 5. Upper chamber; 6. Pressure relief pipe; 7. Lower chamber; 8. Pumping pipe; 9. Lower casing; 10. Oil return pipe; 11. Piston; 12. Damping control valve; 13. Oil drain pipe; 14. Oil storage chamber; 15. Pull plate; 16. First sealing gasket; 17. Hydraulic cylinder; 18. Energy storage assembly; 19. Arc sealing block; 20. Slot; 21. Second sealing gasket; 22. Fixing plate; 23. Upper casing; 24. Impact rod. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0030] The following describes an embodiment of the present invention based on its overall structure.

[0031] Example 1: Please refer to Figures 1-12 The sealed follow-up hydraulic jar shown includes a cylinder 1, a drill string 2, a connecting head 3, an impact rod 24, a reset mechanism, a jarring mechanism and a circulation mechanism, wherein the upper end of the cylinder 1 is elastically connected to the drill string 2, and the lower end is connected to the connecting head 3. A drill bit is provided on the outer wall of the connecting head 3. When a drill bit is stuck during operation, the drill string 2 is lifted up by a large hook so that the drill string 2 slides upward, wherein a fixed plate 22 is provided on the top of the impact rod 24, wherein a pulling plate 15 cooperating with the fixing plate 22 is provided inside the drill string 2. In the process of lifting the drill string 2, the pulling plate 15 will move upward with the drill string 2. When the top of the pulling plate 15 contacts the bottom of the fixing plate 22, the two are in a limited state. As the drill string 2 continues to slide upward, the impact rod 24 is driven to slide upward by the cooperation of the fixing plate 22 and the pulling plate 15. A hydraulic cylinder 17 is provided inside the cylinder 1, wherein an impact rod 24 is slidably provided in the hydraulic cylinder 17, and a piston 11 is slidably provided in the hydraulic cylinder 17, wherein the piston 11 is located on the outer wall of the impact rod 24, and under the action of the piston 11, the hydraulic cylinder 17 is divided into an upper chamber 5 and a lower chamber 7, and an upper shell 23 and a lower shell 9 are fixedly connected between the impact rod 24 and the hydraulic cylinder 17, wherein a second sealing rubber gasket 21 is provided in both the upper shell 23 and the lower shell 9, and a first sealing rubber gasket 16 is installed on the outer wall of the impact rod 24. Under normal pressure, the hydraulic oil in the hydraulic cylinder 17 is sealed by the second sealing rubber gasket 21 in cooperation with the first sealing rubber gasket 16; When the impact rod 24 slides upward through the drill string 2, the piston 11 will slide upward in the hydraulic cylinder 17. During this process, the piston 11 squeezes the space of the upper chamber 5. During this process, the hydraulic oil in the upper chamber 5 is compressed. At the same time, a pressure relief pipe 6 and an oil return pipe 10 are respectively provided at the hydraulic cylinder 17 in the interlayer of the cylinder 1, wherein a damping control valve 12 is provided in the pressure relief pipe 6 and the oil return pipe 10, and the two ends of the pressure relief pipe 6 and the oil return pipe 10 are respectively connected to the upper chamber 5 and the lower chamber 7. Due to the flow restriction of the damping control valve 12, the hydraulic oil cannot flow quickly to the lower chamber, which will cause the pressure in the upper chamber 5 to begin to rise. In addition, an arc-shaped sealing block 19 is provided at the bottom of the first sealing gasket 16 on the impact rod 24, wherein the top of the arc-shaped sealing block 19 is rigidly sealed with the upper shell 23 and the lower shell 9 respectively, which effectively prevents the leakage of the hydraulic oil therein, thereby ensuring the pressure in the upper chamber 5 under high pressure and improving the shock effect of the subsequent impact rod 24; When the piston 11 slides upward through the impact rod 24, a certain cavity will be generated in the lower chamber 7. At this time, the electrically controlled one-way valve in the oil extraction pipe 8 is opened, and the hydraulic oil in the oil storage chamber 14 is extracted into the lower chamber 7 to avoid cavitation and ensure that the pressure in the lower chamber is within a certain range. When the pressure in the upper chamber 5 reaches a certain value, the damping control valve 12 will be fully opened, and the hydraulic oil resistance of the upper chamber 5 and the lower chamber 7 will disappear instantly. At this time, the cylinder enters a state of free energy release, and the hydraulic oil in the high-pressure state will be discharged into the lower chamber 7 through the pressure relief pipe 6, and the impact piston 11 will be ejected upward. An impact seat 4 cooperating with the impact rod 24 is provided in the drill string 2, and the impact rod 24 will impact the impact seat 4 at the top to generate a certain shock force. After the shock is completed, the impact rod 24 itself will drive the piston 11 to slide downward. At this time, the damping control valve 12 in the return oil pipe 10 opens, allowing part of the hydraulic oil to flow back to the upper chamber. At the same time, the oil drain pipe 13 will allow part of the hydraulic oil to flow back to the oil storage chamber, and the piston 11 returns to its initial position, waiting for the next lifting cycle.

[0032] In the above embodiment, please refer to Figure 2 and Figure 5 The drill string 2 and the barrel 1 are connected in a clamping manner, and an elastic component is connected between the drill string 2 and the barrel 1. During the process of lifting the drill string 2, the elastic component inside it is in a stretched state, and when it continues to slide, the internal impact rod 24 will be lifted. After the subsequent impact rod 24 completes the shock, the impact rod 24 will drive the piston 11 to slide downward under the action of the reset force of the elastic component and the gravity of the impact rod 24 itself.

[0033] In the above embodiment, please refer to Figure 4 The energy storage assembly 18 includes a bladder accumulator and a frame, wherein the frame is located at the top of the hydraulic cylinder 17, and a bladder accumulator is provided on the frame. The bladder accumulator is filled with nitrogen. By filling the bladder accumulator with nitrogen, the pre-charge pressure of the nitrogen is 10 MPa. When the pressure in the upper chamber 5 gradually increases, when the pressure exceeds the nitrogen pre-charge pressure, the bladder accumulator automatically contracts. At this time, the hydraulic oil in the accumulator is pressurized synchronously with the upper chamber 5, which is equivalent to expanding the energy storage space of the upper chamber to prevent the cylinder 1 from being cracked due to excessive pressure.

[0034] Example 2: Please refer to Figure 7 and Figure 8 A sealed follow-up hydraulic jar is shown, and its overall structure is similar to that of Example 1, wherein slots 20 are provided in both the upper shell 23 and the lower shell 9, wherein the slots 20 are located at the top of the second sealing pad 21, and the first sealing pad 16 will follow the impact rod 24 to slide into the slot 20, preventing the subsequent impact rod 24 from over-extruding and causing excessive deformation of the two sets of sealing pads, thereby ensuring the sealing effect between the subsequent two sets of sealing pads. At the same time, during the impact process of the impact rod 24, the setting of the slots 20 prevents the first sealing pad 16 from absorbing part of the shock force, thereby ensuring that the shock force is stably transmitted to the drill bit at the bottom.

[0035] The present invention is specifically used in the following manner: when in use, it is connected to the drill bit through the connector 3. When a drill is stuck during drilling, the worker lifts the drill string 2 through the large hook. At this time, the drill string 2 is first stretched by itself under the action of the elastic component, and then the impact rod 24 slides upward under the cooperation of the fixed plate 22 and the pull plate 15. During this process, the impact rod 24 drives the piston 11 on the outer wall to slide upward in the hydraulic cylinder 17. At this time, the space of the upper chamber 5 in the hydraulic cylinder 17 is compressed. Under the action of the damping control valve 12, the hydraulic oil cannot flow quickly into the lower chamber 7. At this time, the pressure in the upper chamber 5 begins to increase, and during the sliding of the impact rod 24, the arc-shaped sealing block 19 on its outer wall will rigidly seal the upper shell 23 and the lower shell 9. In this process, it is achieved that no hydraulic oil leakage occurs under high pressure. As the pressure in the upper chamber 5 increases and reaches a certain value, its damping control valve 12 is in a fully open state. At this time, the pressure of the hydraulic oil in the upper chamber 5 is completely released, so that the hydraulic oil in the high-pressure state will be discharged into the lower chamber 7 through the damping control valve 12. The high-pressure hydraulic oil will impact the piston 11, so that the piston 11 pushes the impact rod 24 to eject upward. When the impact rod 24 reaches a fixed point, it will contact the impact seat 4 and cause a rigid collision. This impact force is transmitted along the impact rod 24 to the stuck drill bit, overcoming the holding force of the drill bit to achieve unblocking. After the impact, the piston 11 is reset and slid downward under the action of the elastic component. During this process, the internal hydraulic oil will be discharged into the upper chamber 5 through the return oil pipe 10, waiting for the next lifting cycle. If the unblocking is not completed in one impact, the above process is repeated.

[0036] Although an embodiment of the present invention has been shown and described, this specific embodiment is merely an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions and variations to the embodiment without creative contribution as needed without departing from the principles and purpose of the present invention. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A sealed follow-up hydraulic jar, comprising a barrel (1), a drill string (2) and a connector (3), wherein the upper end of the barrel (1) is elastically connected to the drill string (2), and the lower end is connected to the connector (3), characterized in that: A hydraulic cylinder (17) is provided inside the cylinder (1), wherein an impact rod (24) is slidably provided inside the hydraulic cylinder (17), an impact seat (4) cooperating with the impact rod (24) is provided inside the drill string (2), and an upper casing (23) and a lower casing (9) are fixedly connected between the impact rod (24) and the hydraulic cylinder (17); A second sealing rubber pad (21) is provided in both the upper shell (23) and the lower shell (9), a first sealing rubber pad (16) is installed on the outer wall of the impact rod (24), and an arc-shaped sealing block (19) is provided on the impact rod (24) at the bottom of the first sealing rubber pad (16), wherein the top of the arc-shaped sealing block (19) is rigidly sealed with the upper shell (23) and the lower shell (9), respectively.

2. A sealed follow-up hydraulic jar according to claim 1, characterized in that: A fixing plate (22) is provided on the top of the impact rod (24), wherein a pulling plate (15) cooperating with the fixing plate (22) is provided inside the drill string (2).

3. The sealed follower hydraulic jar according to claim 1, characterized in that: A piston (11) is slidably provided in the hydraulic cylinder (17), wherein the piston (11) is located on the outer wall of the impact rod (24), and under the action of the piston (11), the hydraulic cylinder (17) is divided into an upper chamber (5) and a lower chamber (7), and a pressure relief pipe (6) and an oil return pipe (10) are respectively provided at the hydraulic cylinder (17) in the interlayer of the cylinder (1), wherein a damping control valve (12) is provided in both the pressure relief pipe (6) and the oil return pipe (10), and both ends of the pressure relief pipe (6) and the oil return pipe (10) are respectively connected to the upper chamber (5) and the lower chamber (7).

4. The sealed follower hydraulic jar according to claim 3, characterized in that: An oil storage chamber (14) is provided at the bottom of the hydraulic cylinder (17) in the cylinder (1), and an oil extraction pipe (8) and an oil discharge pipe (13) are respectively connected between the oil storage chamber (14) and the lower chamber (7), wherein both the oil extraction pipe (8) and the oil discharge pipe (13) are provided with an electrically controlled one-way valve.

5. The sealed follower hydraulic jar according to claim 1, characterized in that: An energy storage component (18) is provided at the top of the hydraulic cylinder (17), and the energy storage component (18) itself is detachably provided.

6. The sealed follower hydraulic jar according to claim 1, characterized in that: The upper shell (23) and the lower shell (9) are both provided with a slot (20), wherein the slot (20) is located on the top of the second sealing pad (21).

7. The sealed follower hydraulic jar according to claim 1, characterized in that: The drill string (2) and the cylinder (1) are arranged in a clamping manner, and an elastic component is connected between the drill string (2) and the cylinder (1).

8. The sealed follower hydraulic jar according to claim 1, characterized in that: The connector (3) and the cylinder (1) are welded together, and an outer wall of the connector (3) is provided with an external thread.

9. The sealed follower hydraulic jar according to claim 5, characterized in that: The energy storage assembly (18) comprises a bladder accumulator and a frame, wherein the frame is located at the top of the hydraulic cylinder (17), and the bladder accumulator is arranged on the frame, and the bladder accumulator is filled with nitrogen.

10. The sealed follower hydraulic jar according to claim 4, characterized in that: The outer wall of the lower casing (9) and the inner wall of the oil storage cavity (14) are smooth.

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