Hydraulic low frequency impactor for oil drilling

Abstract

The present invention relates to a hydraulic low-frequency impactor for oil drilling, comprising an upper joint, an outer tube, an accumulator, a live valve, an upper anvil, and a lower joint. The upper anvil is screwed between the outer tube and the lower joint, the middle inner wall of the lower joint is provided with a lower anvil, a punch rod is inserted into the inner hole of the upper anvil, the lower end of the punch rod is screwed with a hammer, and the hammer is located between the upper anvil and the lower anvil; a live valve is provided at the upper end of the punch rod, the live valve is located in the live valve jacket, and the live valve jacket is screwed between the upper joint and the upper port of the outer tube. The upper end of the punch rod center hole extends to the upper end opening of the punch rod; the upper end of the punch rod large diameter section is provided with a punch rod large convex ring and a large piston is installed, and the punch rod radial hole is provided on the punch rod circumference between the large piston lock nut and the upper anvil and is connected with the punch rod center hole. The upper part of the punch rod medium diameter section is provided with a punch rod small convex ring and a small piston is installed, and the small diameter section of the punch rod is above the small piston. The manufacturing cost of the hydraulic low-frequency impactor for oil drilling is low, the action is reliable, and the service life is long.

Description

Technical Field

[0001] The invention relates to an impactor for unblocking, in particular to a hydraulic low-frequency impactor for oil drilling, belonging to the technical field of oil mining drilling tools. Background Art

[0002] In the production process of oil and water wells, drill bit stuck often occurs due to various factors. There are many treatment options depending on the type of drill bit stuck. Among all the treatment options, hydraulic jar unblocking is a common one. Traditional hydraulic jars are mainly single-shot jars. After one jar, the jar must be reset before the next jar can be made. However, in some special cases, continuous high-frequency jarring is required. Traditional jars have a long interval and the jarring effect is often not obvious.

[0003] Impactors are widely used in oil drilling and can generate high-frequency vibrations. At present, impactors for drilling are generally equipped with a hollow hammer with a piston, and a live valve is provided on the upper part. The mud flows to the drill bit through the center of the anvil of the hammer and the lower joint of the hammer. The spring on the hammer forces the hammer to contact the valve to close the central flow channel of the hammer. Under the action of the upper mud pressure, the hammer and the valve move downward at high speed, impacting the anvil and the drill bit. The live valve is first opened due to the travel limit mechanism and returns to its original position under the action of the spring. Then, the hammer moves upward to the valve under the rebound of the anvil and the spring force, and begins to reciprocate up and down, generating a high-frequency impact on the drill bit.

[0004] Traditional high-frequency impactors have low fluid energy conversion efficiency due to the need to use springs. Springs are prone to breakage during repeated vibrations, and conventional seals are generally used on the hammer, which have low strength and short life under high-speed movement conditions. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of easy breakage of springs and easy damage of seals in the prior art, and to provide a hydraulic low-frequency impactor for oil drilling, which has low manufacturing cost, reliable operation and long service life.

[0006] In order to solve the above technical problems, a hydraulic low-frequency impactor for oil drilling of the present invention comprises an upper joint, an outer tube, an upper anvil and a lower joint, the outer circumference of the upper end of the upper anvil is screwed into the lower port of the outer tube, the outer circumference of the lower end of the upper anvil is screwed into the upper port of the lower joint, the middle inner wall of the lower joint is provided with an inner step serving as the lower anvil, a punch rod with a clearance fit is inserted into the inner hole of the upper anvil, a hammer is screwed at the lower end of the punch rod, and the hammer is located between the upper anvil and the lower anvil; a live valve for controlling the punch rod is provided at the upper end of the punch rod, the live valve comprises a live valve sleeve, and the live valve sleeve is screwed between the upper joint and the upper port of the outer tube.

[0007] Compared with the prior art, the present invention has achieved the following beneficial effects: when the live valve is opened, at a certain displacement, when the water flows through the clearance between the punch rod and the upper anvil, a certain throttling pressure difference will be generated, and the hydraulic pressure above the upper anvil will cause the punch rod to move upward. When the upper end of the punch rod contacts the live valve, the live valve closes the upper port of the punch rod, the liquid flow is blocked, and a water hammer effect is generated; under the action of inertia, the hammer continues to move upward, hits the upper anvil, and causes the pipe string to vibrate. At the end of the upward movement, under the action of water flow and deadweight, the punch rod and the hammer quickly return downward, and impact the lower anvil in the lower joint with greater kinetic energy, completing the downward impact action, and at this time the upper port of the punch rod is separated from the live valve again. In this way, the hammer continuously reciprocates between the upper anvil and the lower anvil, causing the stuck pipe string to vibrate, thereby achieving the purpose of unblocking.

[0008] As an improvement of the present invention, the punch rod has a thin upper part and thick lower part structure, a punch rod center hole with a closed lower end is provided along the axis of the punch rod, and the upper end of the punch rod center hole extends to the upper end opening of the punch rod; the large diameter section of the punch rod extends upward from the inner hole of the upper anvil, and the upper end of the large diameter section of the punch rod is provided with a large punch rod convex ring protruding outward, and a large piston is installed below the large punch rod convex ring, and the outer circumference of the large piston is fitted to the inner wall of the large aperture section of the outer cylinder, and a large piston lock nut is pressed below the large piston, and the large piston lock nut is screwed onto the external thread of the large diameter section of the punch rod, and punch rod radial holes are symmetrically provided on the circumference of the large diameter section of the punch rod between the lower end surface of the large piston lock nut and the upper end surface of the upper anvil, and the punch rod radial holes are communicated with the punch rod center hole. When the upper end of the punch rod is separated from the live valve, the liquid flows into the center hole of the punch rod and flows downward, flows outward from the radial hole of the punch rod, and enters the annular space of the lower chamber of the large piston. The hydraulic pressure acts on the lower end face of the large piston, pushing the large piston to drive the punch rod upward. When the upper end of the punch rod contacts the live valve, the live valve closes the upper end of the punch rod, the liquid flow is blocked, and a water hammer effect is generated; under the action of inertia, the hammer continues to move upward and hits the upper anvil, causing the pipe string to vibrate. After the liquid flow in the center hole of the punch rod is blocked, the hydraulic pressure in the lower chamber of the large piston drops rapidly. Under the action of water flow and deadweight, the punch rod and the hammer return quickly, and impact the lower anvil in the lower joint with greater kinetic energy, completing the downward impact action. At this time, the upper end of the punch rod is separated from the live valve again.

[0009] As a further improvement of the present invention, the upper part of the punch rod large convex ring is the punch rod medium diameter section, the upper part of the punch rod medium diameter section is provided with a punch rod small convex ring protruding outward, the upper part of the punch rod small convex ring is the punch rod small diameter section, the upper part of the punch rod small convex ring is installed with a small piston, the outer periphery of the small piston is attached to the inner wall of the small aperture section of the outer cylinder, a small piston lock nut is pressed above the small piston, and the small piston lock nut is screwed on the external thread of the punch rod small diameter section. When the upper port of the punch rod is in contact with the live valve, the liquid flow in the center hole of the punch rod is blocked, and the liquid flow around the punch rod acts on the upper end face of the small piston, pushing the punch rod downward, and at the same time, under the deadweight of the punch rod and the hammer, the hammer impacts the lower anvil with a large kinetic energy, completing the downward impact action, causing the pipe string to vibrate. At this time, the upper end of the punch rod has been separated from the live valve. A part of the liquid flow enters the center hole of the punch rod and flows downward, flows outward from the radial hole of the punch rod, enters the annular space of the lower cavity of the large piston, and acts on the lower end face of the large piston; the other part of the liquid flow still acts on the upper end face of the small piston. Since the area of ​​the large piston is larger than that of the small piston, the resultant force is upward, forcing the punch rod to move upward. When the upper end of the punch rod contacts the live valve, the live valve closes the upper end of the punch rod, the liquid flow is blocked, and a water hammer effect is generated; under the action of inertia, the hammer continues to move upward and hits the upper anvil, causing the pipe string to vibrate again. In this way, the hammer keeps reciprocating between the upper anvil and the lower anvil, causing the stuck pipe string to vibrate and achieve the purpose of unblocking. The hammer and the live valve are not reset with the help of springs, and the action is reliable and the service life is long.

[0010] As a further improvement of the present invention, a valve seat is provided in the lower inner cavity of the living valve housing, and a valve seat center hole with a closed upper end is provided in the center of the valve seat, a valve core is inserted in the valve seat center hole, and the valve core has an inverted T-shaped cross-section that is narrow at the top and wide at the bottom; an upwardly recessed valve core groove is provided in the center of the lower end surface of the valve core, and an upwardly extending valve core center countersunk hole is provided in the center of the bottom wall of the valve core groove, an annular area on the outer periphery of the valve core groove cooperates with the upper port of the punch rod, and a disc spring is supported between the large end back side of the valve core and the lower end surface of the valve seat; a living valve water through hole that penetrates axially is provided in the portion of the valve seat close to the inner wall of the living valve housing. The groove of the valve core reduces the processing area of ​​the valve core sealing surface, and the center countersunk hole of the valve core reduces the weight of the valve core, making it more flexible; the cross-sectional area of ​​the lower end of the valve core is large, and the liquid flowing downward from the center hole of the upper joint passes through the water hole of the live valve, acts on the step of the valve core, and pushes the valve core downward together with the disc spring, so that the valve core is pressed on the upper port of the punch rod, ensuring reliable blocking of the liquid flow in the center hole of the punch rod. When the punch rod returns upward with the greater lift generated by the large piston, the punch rod contacts the valve core sealing surface again and pushes the valve core upward, and the disc spring is compressed. The elasticity of the disc spring ensures reliable contact between the valve core and the upper port of the punch rod on the one hand, and stores energy when compressed on the other hand, making the downward movement of the valve core more powerful and faster, and accelerating the speed of the hammer's downward strike.

[0011] As a further improvement of the present invention, a limit sleeve for limiting the downward stroke of the valve core is installed on the step on the upper part of the inner wall of the small-diameter section of the outer cylinder, the lower end of the outer sleeve of the live valve is pressed on the limit sleeve, the upper part of the small-diameter section of the punch rod passes through the central hole of the limit sleeve, and the limit sleeve is provided with a limit sleeve water tank for water flow to pass through. When the upper port of the punch rod is in contact with the live valve, the liquid flow in the central hole of the punch rod is blocked, and the liquid flow around the punch rod acts on the upper end face of the small piston, pushing the punch rod downward. At this time, the disc spring pushes the valve core downward synchronously, so that the sealing surface of the valve core remains in contact with the upper port of the punch rod, and the hammer impacts the lower anvil with a large kinetic energy to complete the downward impact action, causing the pipe string to vibrate. When the valve core contacts the limit sleeve, it stops descending. The punch continues to descend under the action of liquid pressure, gravity and inertia to complete the impact. At this time, the upper port of the punch is opened, and the liquid flows into the center hole of the punch, and then quickly enters the lower chamber of the large piston. The lift generated by the large piston is greater than the resistance of the small piston, causing the punch to move upward. When the upper end of the punch contacts the valve core again, the live valve closes the upper port of the punch, the liquid flow is blocked, and a water hammer effect is generated. Under the action of inertia, the hammer continues to move upward and hits the upper anvil, causing the pipe string to vibrate again.

[0012] As a further improvement of the present invention, a valve core sealing ring is installed on the upper part of the valve core to fit with the center hole of the valve seat, and the upper end of the center hole of the valve seat is connected to a radial hole of the valve seat extending radially outward and penetrating, and the outer end of the radial hole of the valve seat is screwed with a live valve filter plug. The valve core sealing ring seals the upper end of the valve core with the center hole of the valve seat. When the valve core moves upward, it pushes the liquid flow in the center hole of the valve seat to be discharged from the radial hole of the valve seat and the live valve filter plug; when the valve core moves downward, the liquid flow is filtered by the live valve filter plug, enters the center hole of the valve seat from the radial hole of the valve seat, and replenishes the upper cavity of the valve core, so that the resistance of the valve core when moving up and down can be reduced, making the action of the live valve more sensitive.

[0013] As a further improvement of the present invention, the lower part of the small-aperture section of the outer cylinder is symmetrically provided with outer cylinder water filter holes that penetrate in the radial direction, and the outer ends of the outer cylinder water filter holes are respectively screwed with outer cylinder filter plugs, and the outer cylinder water filter holes are located between the small convex circle of the punch rod and the large convex circle of the punch rod in the height direction. When the large piston pushes the punch rod upward, the volume of the upper chamber of the large piston gradually decreases, and the liquid is discharged from the outer cylinder filter plug. When the valve core closes the upper port of the center hole of the punch rod and the small piston pushes the punch rod downward, the lower chamber of the large piston loses pressure, and the liquid flows out from the residual gap between the punch rod and the upper anvil. The volume of the upper chamber of the large piston gradually increases, and the external liquid flows into the upper chamber of the large piston after filtering the outer cylinder filter plug. In this way, the resistance of the punch rod when it moves upward or downward can be reduced, making the impact of the hammer more powerful.

[0014] As a further improvement of the present invention, the middle outer periphery of the upper anvil is provided with an upper anvil convex ring protruding outward, the lower port of the outer tube is pressed on the upper end surface of the upper anvil convex ring, and the upper port of the lower joint is pressed on the lower end surface of the upper anvil convex ring. The upper anvil convex ring is conducive to axial positioning between the upper anvil, the outer tube and the lower joint, and can be fixed with a set screw to prevent loosening after being screwed to the bottom.

[0015] As a further improvement of the present invention, an upper joint inner boss protruding toward the axial direction is provided below the tapered female thread of the upper joint, and a plurality of upper joint water holes penetrating along the axial direction are provided on the circumference of the upper joint inner boss, and an accumulator assembly extending downward is screwed into the inner hole of the upper joint inner boss. The upper joint water holes on the upper joint inner boss keep the fluid flow between the upper joint center hole and the piston unobstructed. When the punch rod moves upward, the fluid flow in the upper chamber of the small piston flows upward from the water hole of the active valve, so that the upper chamber of the valve seat generates high pressure, and the hydraulic energy can be stored in the accumulator assembly to increase the kinetic energy of the hammer when it strikes downward.

[0016] As a further improvement of the present invention, the accumulator assembly includes an accumulator cylinder with a closed top and an open bottom, an accumulator screw head is screwed to the lower end of the accumulator cylinder, a through screw head center hole is provided along the axis of the accumulator screw head, an accumulator piston matching the inner wall of the accumulator cylinder is provided above the accumulator screw head, and an accumulator spring is supported between the top surface of the accumulator piston and the top wall of the accumulator cylinder. When the large piston pushes the punch rod upward, the volume of the upper chamber of the small piston becomes smaller, and the liquid flows into the upper chamber of the valve seat through the water hole of the live valve, so that the pressure of the upper chamber of the valve seat increases, the accumulator piston moves upward under the action of hydraulic pressure, the accumulator spring is compressed, and the hydraulic energy is converted into the elastic potential energy of the accumulator spring, while reducing the resistance of the hammer when it moves upward and increasing the impact force of the hammer. When the hammer completes the upward strike, the upper port of the punch rod is closed by the valve core, causing the lower chamber of the large piston to lose pressure. The liquid flow and gravity push the small piston downward. At this time, the accumulator spring pushes the accumulator piston downward, increasing the pressure on the small piston and making the hammer's downward strike more powerful. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The accompanying drawings are only provided for reference and explanation and are not intended to limit the present invention.

[0018] Figure 1 It is a front view of the hydraulic low-frequency impactor used for oil drilling of the present invention.

[0019] Figure 2 for Figure 1 Schematic diagram of the structure of the middle hammer assembly.

[0020] Figure 3 for Figure 1 Enlarged view of the upper middle part.

[0021] Figure 4 for Figure 1 Enlarged view of the lower middle part.

[0022] In the figure: 1. Upper joint; 1a. Conical female thread; 1b. Water hole of upper joint; 2. Accumulator assembly; 2a. Accumulator cylinder; 2b. Accumulator spring; 2c. Accumulator piston; 2d. Accumulator screw head; 2d1. Center hole of screw head; 3. Live valve; 3a. Live valve jacket; 3b. Valve seat; 3b1. Center hole of valve seat; 3b2. Water hole of live valve; 3b3. Radial hole of valve seat; 3b4. Live valve filter plug; 3c. Valve core; 3c1. Valve core groove; 3c2. Center countersunk hole of valve core; 3d. Valve core sealing ring; 3e. Disc spring; 4. Outer cylinder; 4a. Outer cylinder filter plug; 5. Limit sleeve; 5a. Limit sleeve water tank; 6. Punch rod; 6a. Small diameter section of punch rod; 6b. Small convex ring of punch rod; 6c. Medium diameter section of punch rod; 6d. Large convex ring of punch rod; 6e. Large diameter section of punch rod; 6f. Center hole of punch rod; 6g. Radial hole of punch rod; 7. Small piston; 7a. Small piston lock nut; 8. Large piston; 8a. Large piston lock nut; 9. Hammer; 10. Upper anvil; 10a. Upper anvil convex ring; 11. Lower joint; 11a. Lower anvil; 11b. Tapered male thread. DETAILED DESCRIPTION

[0023] like Figures 1 to 4 As shown, the hydraulic low-frequency impactor for oil drilling of the present invention comprises an upper joint 1, an outer tube 4, an upper anvil 10 and a lower joint 11, the outer circumference of the upper end of the upper anvil 10 is screwed into the lower port of the outer tube 4, the outer circumference of the lower end of the upper anvil 10 is screwed into the upper port of the lower joint 11, the lower end of the lower joint 11 is provided with a tapered male thread 11b connected to the lower pipe column, the middle inner wall of the lower joint 11 is provided with an inner step serving as the lower anvil 11a, a punch rod 6 with a clearance fit is inserted into the inner hole of the upper anvil 10, a hammer 9 is screwed into the lower end of the punch rod 6, and the hammer 9 is located between the upper anvil 10 and the lower anvil 11a; a live valve 3 for controlling the punch rod 6 is provided at the upper end of the punch rod 6, the live valve 3 comprises a live valve sleeve, and the live valve sleeve is screwed between the upper joint 1 and the upper port of the outer tube 4.

[0024] The upper anvil 10 is provided with an upper anvil convex ring 10a protruding outward at the middle outer periphery, the lower end of the outer tube 4 is pressed on the upper end surface of the upper anvil convex ring 10a, and the upper end of the lower joint 11 is pressed on the lower end surface of the upper anvil convex ring 10a. The upper anvil convex ring 10a is conducive to the axial positioning between the upper anvil 10, the outer tube 4 and the lower joint 11, and can be fixed with a set screw to prevent loosening after being screwed to the bottom.

[0025] When the live valve is opened, at a certain displacement, when the water flows through the clearance between the punch rod 6 and the upper anvil 10, a certain throttling pressure difference will be generated. The hydraulic pressure above the upper anvil 10 makes the punch rod 6 move upward. When the upper end of the punch rod 6 contacts the live valve, the live valve closes the upper port of the punch rod 6, the liquid flow is blocked, and a water hammer effect is generated; under the action of inertia, the hammer 9 continues to move upward, hits the upper anvil 10, and causes the pipe string to vibrate. At the end of the upward movement, under the action of water flow and deadweight, the punch rod 6 and the hammer 9 quickly return downward, and impact the lower anvil 11a in the lower joint 11 with greater kinetic energy, completing the downward impact action. At this time, the upper port of the punch rod 6 is separated from the live valve again. In this way, the hammer 9 continuously reciprocates between the upper anvil 10 and the lower anvil 11a, causing the stuck pipe string to vibrate and achieve the purpose of unblocking.

[0026] The punch rod 6 has a thin upper and thick lower structure, and a punch rod center hole 6f with a closed lower end is provided along the axis of the punch rod 6, and the upper end of the punch rod center hole 6f extends to the upper end opening of the punch rod 6; the punch rod large diameter section 6e extends upward from the inner hole of the upper anvil 10, and the upper end of the punch rod large diameter section 6e is provided with a large punch rod convex ring 6d protruding outward, and a large piston 8 is installed below the large punch rod convex ring 6d, and the outer periphery of the large piston 8 is fitted to the inner wall of the large aperture section of the outer cylinder, and a large piston lock nut 8a is pressed below the large piston 8, and the large piston lock nut 8a is screwed onto the external thread of the punch rod large diameter section 6e, and punch rod radial holes 6g are symmetrically provided on the circumference of the punch rod large diameter section 6e between the lower end surface of the large piston lock nut 8a and the upper end surface of the upper anvil 10, and the punch rod radial holes 6g are connected with the punch rod center hole 6f. When the upper end of the punch rod 6 is separated from the live valve, the liquid flows into the punch rod center hole 6f and flows downward, flows outward from the punch rod radial hole 6g, and enters the annular space of the lower chamber of the large piston 8. The hydraulic pressure acts on the lower end surface of the large piston 8, pushing the large piston 8 to drive the punch rod 6 upward. When the upper end of the punch rod 6 contacts the live valve, the live valve closes the upper end of the punch rod 6, the liquid flow is blocked, and a water hammer effect is generated; under the action of inertia, the hammer 9 continues to move upward and hits the upper anvil 10, causing the pipe string to vibrate. After the liquid flow in the punch rod center hole 6f is blocked, the hydraulic pressure in the lower chamber of the large piston 8 drops rapidly. Under the action of water flow and deadweight, the punch rod 6 and the hammer 9 return quickly, and impact the lower anvil 11a in the lower joint 11 with greater kinetic energy, completing the downward impact action. At this time, the upper end of the punch rod 6 is separated from the live valve again.

[0027] The upper part of the punch rod large convex ring 6d is the punch rod middle diameter section 6c, the upper part of the punch rod middle diameter section 6c is provided with a punch rod small convex ring 6b protruding outward, the upper part of the punch rod small convex ring 6b is the punch rod small diameter section 6a, the upper part of the punch rod small convex ring 6b is installed with a small piston 7, the outer periphery of the small piston 7 is attached to the inner wall of the small aperture section of the outer cylinder, the upper part of the small piston 7 is pressed with a small piston lock nut 7a, and the small piston lock nut 7a is screwed on the external thread of the punch rod small diameter section 6a. When the upper port of the punch rod 6 is in contact with the live valve, the liquid flow of the punch rod center hole 6f is blocked, and the liquid flow of the outer periphery of the punch rod 6 acts on the upper end surface of the small piston 7, pushing the punch rod 6 downward, and at the same time, under the deadweight of the punch rod 6 and the hammer 9, the hammer 9 impacts the lower anvil 11a with a large kinetic energy, completing the downward impact action, causing the pipe string to vibrate. At this time, the upper port of the punch rod 6 has been separated from the live valve, and part of the liquid flow enters the punch rod center hole 6f and flows downward, flows outward from the punch rod radial hole 6g, enters the annular space of the lower cavity of the large piston 8, and acts on the lower end face of the large piston 8; the other part of the liquid flow still acts on the upper end face of the small piston 7. Since the area of ​​the large piston 8 is larger than that of the small piston 7, the resultant force is upward, forcing the punch rod 6 to move upward. When the upper end of the punch rod 6 contacts the live valve, the live valve closes the upper port of the punch rod 6, the liquid flow is blocked, and a water hammer effect is generated; under the action of inertia, the hammer 9 continues to move upward and hits the upper anvil 10, causing the pipe string to vibrate again. In this way, the hammer 9 keeps reciprocating between the upper anvil 10 and the lower anvil 11a, causing the stuck pipe string to vibrate and achieving the purpose of unblocking. The hammer 9 and the live valve are not reset with the help of a spring, and the action is reliable and the service life is long.

[0028] A valve seat 3b is provided in the lower inner cavity of the live valve housing 3a, and a valve seat center hole 3b1 with a closed upper end is provided in the center of the valve seat 3b, and a valve core 3c is inserted in the valve seat center hole 3b1, and the valve core 3c has an inverted T-shaped cross-section that is narrow at the top and wide at the bottom; an upwardly recessed valve core groove 3c1 is provided in the center of the lower end surface of the valve core 3c, and an upwardly extending valve core center countersunk hole 3c2 is provided in the center of the bottom wall of the valve core groove 3c1, and an annular area on the outer periphery of the valve core groove 3c1 cooperates with the upper port of the punch rod 6, and a disc spring 3e is supported between the large end back side of the valve core 3c and the lower end surface of the valve seat 3b; a live valve water through hole 3b2 that penetrates axially is provided in the portion of the valve seat 3b close to the inner wall of the live valve housing 3a. The valve core groove 3c1 reduces the processing area of ​​the valve core sealing surface, and the valve core center countersunk hole 3c2 reduces the weight of the valve core 3c, making it more flexible; the cross-sectional area of ​​the lower end of the valve core 3c is large, and the liquid flowing downward from the center hole of the upper joint passes through the live valve water hole 3b2, acts on the step of the valve core 3c, and pushes the valve core 3c downward together with the disc spring 3e, so that the valve core 3c is pressed on the upper port of the punch rod 6, ensuring reliable blocking of the liquid flow of the punch rod center hole 6f. When the punch rod 6 returns upward by relying on the greater lift generated by the large piston 8, the punch rod 6 contacts the valve core sealing surface again and pushes the valve core 3c upward, and the disc spring 3e is compressed. The elasticity of the disc spring 3e ensures reliable contact between the valve core 3c and the upper port of the punch rod, and on the other hand, it stores energy when compressed, making the valve core 3c move downward more powerfully and faster, and accelerating the speed of the hammer 9.

[0029] A limit sleeve 5 for limiting the downward stroke of the valve core 3c is installed on the step on the upper part of the inner wall of the small-diameter section of the outer cylinder, the lower end of the outer sleeve 3a of the live valve is pressed on the limit sleeve 5, the upper part of the small-diameter section 6a of the punch rod passes through the central hole of the limit sleeve 5, and the limit sleeve 5 is provided with a limit sleeve water groove 5a for water flow to pass through. When the upper port of the punch rod 6 is in contact with the live valve, the liquid flow in the central hole 6f of the punch rod is blocked, and the liquid flow around the punch rod 6 acts on the upper end face of the small piston 7, pushing the punch rod 6 downward, at this time, the disc spring 3e pushes the valve core 3c downward synchronously, so that the sealing surface of the valve core 3c remains in contact with the upper port of the punch rod 6, and the hammer 9 impacts the lower anvil 11a with a large kinetic energy, completing the downward impact action, causing the pipe string to vibrate. When the valve core 3c contacts the limit sleeve 5, it stops descending. The punch rod 6 continues to descend under the action of liquid pressure, gravity and inertia to complete the impact. At this time, the upper port of the punch rod 6 is opened, and the liquid flows into the center hole 6f of the punch rod, and then quickly enters the lower cavity of the large piston 8. The lift generated by the large piston 8 is greater than the resistance of the small piston 7, causing the punch rod 6 to move upward. When the upper end of the punch rod 6 contacts the valve core 3c again, the active valve closes the upper port of the punch rod 6, the liquid flow is blocked, and a water hammer effect is generated; under the action of inertia, the hammer 9 continues to move upward and hits the upper anvil 10, causing the pipe string to vibrate again.

[0030] The upper part of the valve core 3c is provided with a valve core sealing ring 3d which fits the valve seat center hole 3b1. The upper end of the valve seat center hole 3b1 is connected with a valve seat radial hole 3b3 which extends radially outward and penetrates. The outer end of the valve seat radial hole 3b3 is screwed with a live valve filter plug 3b4. The valve core sealing ring 3d seals the upper end of the valve core 3c with the valve seat center hole 3b1. When the valve core 3c moves upward, it pushes the liquid flow in the valve seat center hole 3b1 to be discharged from the valve seat radial hole 3b3 and the live valve filter plug 3b4. When the valve core 3c moves downward, the liquid flow is filtered by the live valve filter plug 3b4, enters the valve seat center hole 3b1 from the valve seat radial hole 3b3, and replenishes the upper cavity of the valve core 3c. In this way, the resistance of the valve core 3c when it moves up and down can be reduced, making the action of the live valve more sensitive.

[0031] The lower part of the small-diameter section of the outer cylinder is symmetrically provided with outer cylinder water filter holes that penetrate in the radial direction. The outer ends of the outer cylinder water filter holes are respectively screwed with outer cylinder filter plugs 4a. The outer cylinder water filter holes are located between the small convex ring 6b of the punch rod and the large convex ring 6d of the punch rod in the height direction. When the large piston 8 pushes the punch rod 6 upward, the volume of the upper chamber of the large piston 8 gradually decreases, and the liquid is discharged from the outer cylinder filter plug 4a. When the valve core 3c closes the upper port of the punch rod center hole 6f, the small piston 7 pushes the punch rod 6 downward, the lower chamber of the large piston 8 loses pressure, and the liquid flows out from the clearance between the punch rod 6 and the upper anvil 10. The volume of the upper chamber of the large piston 8 gradually increases, and the external liquid flows into the upper chamber of the large piston 8 after filtering the outer cylinder filter plug 4a. In this way, the resistance of the punch rod 6 when it moves upward or downward can be reduced, making the impact of the hammer 9 more powerful.

[0032] The inner cavity of the upper joint 1 is provided with a tapered female thread 1a connected to the upper pipe column, and an upper joint inner boss protruding in the axial direction is provided below the tapered female thread 1a. A plurality of upper joint water holes 1b penetrating in the axial direction are provided on the circumference of the upper joint inner boss, and an accumulator assembly 2 extending downward is screwed into the inner hole of the upper joint inner boss. The upper joint water holes 1b on the upper joint inner boss keep the liquid flow between the upper joint center hole and the piston unobstructed. When the punch rod 6 moves upward, the liquid flow in the upper cavity of the small piston 7 flows upward from the active valve water hole 3b2, so that the upper cavity of the valve seat 3b generates high pressure, and the hydraulic energy can be stored in the accumulator assembly 2 to increase the kinetic energy of the hammer 9 when it strikes downward.

[0033] The accumulator assembly 2 includes an accumulator cylinder 2a with a closed top and an open bottom, an accumulator screw head 2d is screwed to the lower end of the accumulator cylinder 2a, a screw head center hole 2d1 is provided along the axis of the accumulator screw head 2d, an accumulator piston 2c is provided above the accumulator screw head 2d to match the inner wall of the accumulator cylinder 2a, and an accumulator spring 2b is supported between the top surface of the accumulator piston 2c and the top wall of the accumulator cylinder 2a. When the large piston 8 pushes the punch rod 6 upward, the volume of the upper cavity of the small piston 7 becomes smaller, and the liquid flows into the upper cavity of the valve seat 3b through the water hole 3b2 of the live valve, so that the pressure of the upper cavity of the valve seat increases, the accumulator piston 2c moves upward under the action of hydraulic pressure, the accumulator spring 2b is compressed, and the hydraulic energy is converted into the elastic potential energy of the accumulator spring 2b, while reducing the resistance of the hammer 9 when it moves upward and increasing the impact force of the hammer 9. When the hammer 9 completes the upward impact, the upper port of the punch rod 6 is closed by the valve core 3c, causing the lower chamber of the large piston 8 to lose pressure, and the liquid flow and gravity push the small piston 7 downward. At this time, the accumulator spring 2b pushes the accumulator piston 2c downward, increasing the pressure on the small piston 7, making the downward impact of the hammer 9 more powerful.

[0034] The above are only preferred embodiments of the present invention, and the scope of patent protection of the present invention is not limited thereto. In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention. The technical features not described in the present invention can be realized by or using existing technologies, and will not be repeated here.

Claims

1. A hydraulic low-frequency impactor for oil drilling, comprising an upper joint, an outer tube, an upper anvil and a lower joint, wherein the upper end outer circumference of the upper anvil is screwed into the lower port of the outer tube, and the lower end outer circumference of the upper anvil is screwed into the upper port of the lower joint, characterized in that: The inner wall of the middle part of the lower joint is provided with an inner step as the lower anvil, a punch rod with clearance fit is inserted into the inner hole of the upper anvil, a hammer is screwed on the lower end of the punch rod, and the hammer is located between the upper anvil and the lower anvil; a valve for controlling the punch rod is provided on the upper end of the punch rod, and the valve includes a valve sleeve, and the valve sleeve is screwed between the upper joint and the upper port of the outer cylinder; The punch rod is of a thin-top and thick-bottom structure, a punch rod center hole with a closed lower end is provided along the axis of the punch rod, and the upper end of the punch rod center hole extends to the upper end opening of the punch rod; the punch rod large diameter section extends upward from the inner hole of the upper anvil, and the upper end of the punch rod large diameter section is provided with a large punch rod convex ring protruding outward, and a large piston is installed below the large punch rod convex ring, and the outer circumference of the large piston is fitted to the inner wall of the large-aperture section of the outer cylinder, and a large piston lock nut is pressed below the large piston, and the large piston lock nut is screwed onto the external thread of the large-diameter section of the punch rod, and punch rod radial holes are symmetrically provided on the circumference of the punch rod large diameter section between the lower end face of the large piston lock nut and the upper end face of the upper anvil, and the punch rod radial holes are connected with the punch rod center hole; The upper part of the punch rod large convex ring is the punch rod medium diameter section, the upper part of the punch rod medium diameter section is provided with a punch rod small convex ring protruding outward, the upper part of the punch rod small convex ring is the punch rod small diameter section, a small piston is installed on the upper part of the punch rod small convex ring, the outer periphery of the small piston is attached to the inner wall of the small aperture section of the outer cylinder, a small piston lock nut is pressed on the upper part of the small piston, and the small piston lock nut is screwed on the external thread of the punch rod small diameter section; The middle outer periphery of the upper anvil is provided with an upper anvil convex ring protruding outward, the lower end of the outer tube is pressed on the upper end surface of the upper anvil convex ring, and the upper end of the lower joint is pressed on the lower end surface of the upper anvil convex ring; A valve seat is provided in the lower inner cavity of the living valve housing, and a valve seat center hole with a closed upper end is provided in the center of the valve seat, a valve core is inserted in the center hole of the valve seat, and the valve core is in an inverted T-shaped cross-section which is narrow at the top and wide at the bottom; an upwardly recessed valve core groove is provided in the center of the lower end surface of the valve core, and an upwardly extending valve core center countersunk hole is provided in the center of the bottom wall of the valve core groove, an annular area on the outer periphery of the valve core groove cooperates with the upper port of the punch rod, and a disc spring is supported between the back side of the large end of the valve core and the lower end surface of the valve seat; a living valve water through hole which penetrates axially is provided in the portion of the valve seat close to the inner wall of the living valve housing.

2. The hydraulic low-frequency impactor for oil drilling according to claim 1, characterized in that: A limit sleeve for limiting the downward stroke of the valve core is installed on the step on the upper part of the inner wall of the small-diameter section of the outer cylinder, the lower end of the outer sleeve of the movable valve is pressed on the limit sleeve, the upper part of the small-diameter section of the punch rod passes through the central hole of the limit sleeve, and the limit sleeve is provided with a limit sleeve water groove for water to flow through.

3. The hydraulic low-frequency impactor for oil drilling according to claim 1, characterized in that: A valve core sealing ring is installed on the upper part of the valve core and fits with the valve seat center hole. The upper end of the valve seat center hole is connected to a valve seat radial hole extending radially outward and penetrating therethrough. A live valve filter plug is screwed on the outer end of the valve seat radial hole.

4. The hydraulic low-frequency impactor for oil drilling according to claim 1, characterized in that: The lower part of the outer cylinder small-diameter section is symmetrically provided with outer cylinder water filtering holes that penetrate radially, and the outer ends of the outer cylinder water filtering holes are respectively screwed with outer cylinder filter plugs. The outer cylinder water filtering holes are located between the small convex circle of the punch rod and the large convex circle of the punch rod in the height direction.

5. The hydraulic low-frequency impactor for oil drilling according to any one of claims 1 to 4, characterized in that: An upper joint inner boss protruding toward the axial direction is provided below the tapered female thread of the upper joint, a plurality of upper joint water holes penetrating along the axial direction are provided on the circumference of the upper joint inner boss, and an accumulator assembly extending downward is screwed into the inner hole of the upper joint inner boss.

6. The hydraulic low-frequency impactor for oil drilling according to claim 5, characterized in that: The accumulator assembly includes an accumulator cylinder with a closed top and an open lower end, an accumulator screw head is screwed onto the lower end of the accumulator cylinder, a through screw head center hole is provided along the axis of the accumulator screw head, an accumulator piston matching the inner wall of the accumulator cylinder is provided above the accumulator screw head, and an accumulator spring is supported between the top surface of the accumulator piston and the top wall of the accumulator cylinder.

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