A drilling shock absorber with anti-drop function and drilling tool assembly

Abstract

The present invention provides a drilling shock absorber with an anti-drop function and a drilling tool combination, wherein the drilling shock absorber includes an outer cylinder, an anti-drop connecting rod, a piston rod, a force transmission spline cylinder, an anti-drop outer cylinder, a force transmission spline shaft and an upper dynamic sealing assembly, wherein the outer cylinder is connected with the force transmission spline cylinder to form an outer shell; the anti-drop connecting rod, the piston rod and the force transmission spline shaft are fixedly connected in sequence to form an inner cylinder; the inner cylinder is arranged in the outer shell and can move relative to each other, wherein the outer cylinder limits the anti-drop connecting rod from moving downward relative to the outer cylinder; the anti-drop connecting rod and the piston rod are located in the outer cylinder and a high-pressure oil chamber is formed between the piston rod and the outer wall; the force transmission spline shaft is arranged inside the force transmission spline cylinder and transmits torque; the upper dynamic sealing assembly is arranged on one side or both sides of the high-pressure oil chamber; the anti-drop outer cylinder is arranged on the force transmission spline cylinder and the force transmission spline shaft. The present invention has the advantages of good shock absorbing effect of the shock absorber, wide application range, particularly suitable for gas drilling, reliable sealing, safe anti-drop, long service life, etc.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling engineering, and in particular to a drilling shock absorber with an anti-drop function and a drilling tool assembly. Background Art

[0002] During the oil and gas extraction process, due to the complex geological structure, different strata lithology and hardness, the drill bit will produce rock breaking effect, while the hard rock will also produce impact load on the drill bit and drill tool assembly, vibration load on the drill string, and torsional impact when the drill bit rotates to break the rock, resulting in strong longitudinal vibration, torsional vibration and lateral vibration. These vibrations of different degrees bring huge safety hazards to the drill string assembly and ground equipment, and the fatigue damage of the drill tool caused by vibration, the breakage of the drill string forms a long fish, which greatly reduces the tool life and greatly increases the cost of drilling operations. The specially designed shock absorber in the drill tool assembly can effectively absorb adverse impact and vibration energy, store or convert it into other forms of energy, reduce fatigue damage, and achieve the purpose of protecting the drill tool, improving drilling efficiency and wellbore trajectory accuracy, and reducing drilling costs.

[0003] At present, the shock absorbers commonly used in the air drilling process are mostly hydraulic shock absorbers, spring shock absorbers and hydraulic plus spring composite shock absorbers; hydraulic shock absorbers rely on the elastic deformation of the compressible silicone oil cavity to absorb vibration energy; spring shock absorbers rely on the deformation of spring elements to absorb the vibration energy of drilling tools; hydraulic plus spring composite shock absorbers use the elastic deformation of the compressible silicone oil cavity and the deformation of spring elements to absorb the vibration energy of drilling tools. However, the effect of the shock absorber is related to the stiffness range of the shock absorber. With current technology, the stiffness range of conventional shock absorbers is limited, and the maximum stiffness may not meet the needs of some special working conditions; at the same time, these conventional shock absorbers are mainly aimed at reducing longitudinal vibration, while there are fewer shock absorbers for reducing circumferential torsional vibration. Especially in the conventional hydraulic shock absorbers, due to the inadequate design of the sealing structure, it often leads to oil leakage, insufficient working characteristics, and even failure. In addition, since shock absorbers or anti-fatigue short circuits are added to the drill bit assembly, this part becomes one of the weak links in the entire drill string structure. It is necessary to optimize the design of the shock absorber structure, and add an anti-drop structure on the basis of ensuring the main shock absorbing function and sealing to prevent breakage and cause underground complications, thereby making up for the shortcomings of conventional shock absorbers when applied to air drilling.

[0004] At present, both at home and abroad, whether it is spring shock absorber or hydraulic shock absorber tools, there are relatively mature products widely used on site.

[0005] The publication number is "CN104712259A" and the name is "A fully mechanical bidirectional drill string shock absorber and process method", which discloses a spiral pair composed of an internal trapezoidal thread and an external trapezoidal thread. The torque transmission and vibration conversion mechanism is connected to the sealing mechanism through a threaded connection. The sealing mechanism has a rotary seal and a mud scraper seal in sequence to form a closed chamber; the shock absorbing mechanism is composed of a shock absorbing cylinder, a shock absorbing shaft, and an annular spring, and the annular spring is connected between the shock absorbing cylinder and the shock absorbing shaft; one end of the shock absorbing mechanism is connected to the torque transmission and vibration conversion mechanism through a thread, and the other end of the shock absorbing mechanism is connected to the joint; the structure is compact; it can not only absorb the longitudinal vibration during oil drilling, but also absorb the circumferential torsional vibration during rotary rock breaking; the mechanical shock absorbing element has good shock absorbing effect and a wide range of application. It is suitable for formations of various rock types and hardness, and is not affected by working environment factors such as bottom hole temperature.

[0006] The publication number "CN101705794A" and the name "A bidirectional anti-fatigue short-circuit for a drill string" discloses the use of a disc spring group and a damping piston as a series structure, which can simultaneously slow down or absorb longitudinal vibrations; the buffer rubber at the spline can slow down circumferential vibrations to reduce the harmful effects of unexpected torque on the drill string; the short-circuit shell structure has been analyzed by aerodynamic finite element simulation, and the optimized single-leaf hyperboloid structure at the joint can reduce the erosion effect caused by high-speed airflow during air underbalanced drilling, extend service life, improve work efficiency, and effectively protect the drill bit and drill string.

[0007] The publication number "CN 210714504U" and the name "A four-stage shock absorption drill string shock absorber" discloses that the first stage of shock absorption is achieved in the form of a spring combined with a piston, the second stage of shock absorption is achieved in the form of an elastic rubber ring, the third stage of shock absorption is achieved in the form of a spring combined with a piston again, and the fourth stage of shock absorption is achieved in the form of a compressible liquid combined with a sealing rubber ring. The composite combination of springs, elastic rubber rings, and compressible liquids realizes multi-form composite shock absorption, avoiding the situation where the failure of a single shock absorption leads to overall failure. The four-stage shock absorption makes the device suitable for high-intensity vibration and enhances the shock absorption effect. The inclined surface of the contact surface between the cylinder and the lower joint can convert the lateral vibration of the drill string into axial vibration, thereby realizing axial and lateral multi-directional shock absorption.

[0008] The publication number "CN 201460762U" and the name "A fully hydraulic bidirectional drill string shock absorber" discloses that the oil cylinder is filled with compressible 201-100 dimethyl silicone oil; a first sealing assembly is provided between the straightening sleeve and the mandrel; a second sealing assembly is provided between the oil cylinder and the mandrel and between the lower joint and the mandrel. Since the compressible liquid is compressed and deformed under pressure and flows through the gap between the splines at high speed to absorb the energy of the vibration of the drill bit and the drill string, the shock absorber has a good effect of reducing the vibration and impact load of the drilling tool.

[0009] In summary, the shock absorbers of the above patents have their advantages, but there are still many disadvantages and limitations. In particular, for drilling shock absorbers with anti-drop function, conventional shock absorbers cannot meet their sealing and structural reliability requirements; in addition, adding a shock absorber device to the drill bit assembly makes this part a new weak link, which may cause fatigue failure damage or even fracture accidents at this part, seriously affecting the drilling efficiency, working cycle and cost. Summary of the invention

[0010] In view of the deficiencies in the prior art, the present invention aims to solve one or more problems in the prior art. For example, one of the purposes of the present invention is to provide a drilling shock absorber with good shock absorption effect, wide application range, reliable sealing, and safe anti-drop function. For another example, another purpose of the present invention is to provide a drilling tool assembly with good shock absorption effect, wide application range, reliable sealing, and safe anti-drop function.

[0011] In order to achieve the above-mentioned object, the present invention provides a drilling shock absorber with an anti-drop function, which may include an outer cylinder, an anti-drop connecting rod, a piston rod, a force transmission spline cylinder, an anti-drop outer cylinder, a force transmission spline shaft and an upper dynamic seal assembly, wherein:

[0012] The lower end of the outer cylinder is fixedly connected to the upper end of the force transmission spline cylinder to form the outer shell of the shock absorber;

[0013] The lower part of the anti-drop connecting rod and the upper part of the piston rod are fixedly connected, and the lower part of the piston rod and the upper part of the force transmission spline shaft are fixedly connected to form the inner cylinder part of the shock absorber;

[0014] The inner cylinder part is arranged in the outer shell part and can move relative to it, wherein:

[0015] The outer cylinder can limit the displacement of the anti-drop connecting rod relative to the outer cylinder downward;

[0016] The anti-drop connecting rod and the piston rod are located in the outer cylinder, and a high-pressure oil chamber is formed between the outer wall of the piston rod and the inner wall of the outer cylinder. The volume of the high-pressure oil chamber can be changed when the inner cylinder part and the outer cylinder part move relative to each other, and a compressible liquid is arranged in the high-pressure oil chamber.

[0017] The force transmission spline shaft is arranged inside the force transmission spline cylinder and connected through a spline to transmit torque; the upper dynamic seal assembly is arranged on one side or both sides of the high-pressure oil chamber to form a seal;

[0018] The anti-drop outer cylinder is arranged on the force transmission spline cylinder and the force transmission spline shaft and can limit the downward displacement of the force transmission spline shaft relative to the force transmission spline cylinder.

[0019] In an exemplary embodiment of one aspect of the present invention, the shock absorber may further include a damping channel and a lower dynamic sealing assembly. The damping channel may be arranged between the inner wall of the force transmission spline cylinder and the outer wall of the force transmission spline shaft. The lower dynamic sealing assembly is arranged on one side or both sides of the damping channel to form a seal. The damping channel is filled with a compressible liquid. The compressible liquid flows in the damping channel to form nonlinear damping for shock absorption.

[0020] In an exemplary embodiment of one aspect of the present invention, protruding splines are evenly distributed radially on the outer wall of the force transmission spline shaft, a spline groove cooperating with the splines is provided on the inner wall of the force transmission spline cylinder, and the damping channel is provided in the spline groove.

[0021] In an exemplary embodiment of one aspect of the present invention, a first step protruding outward may be provided on the inner wall of the outer cylinder, and a second step cooperating with the first step may be provided on the upper outer wall of the anti-drop connecting rod, so that the downward displacement of the anti-drop connecting rod in the outer cylinder is limited by the cooperation of the first step and the second step.

[0022] In an exemplary embodiment of one aspect of the present invention, the lower end of the anti-drop outer cylinder can be fixedly connected to the force transmission spline shaft, a third step protruding outward can be provided on the outer wall of the force transmission spline cylinder, and a fourth step cooperating with the third step is provided on the anti-drop outer cylinder. The downward displacement of the force transmission spline shaft relative to the force transmission spline cylinder is limited by the cooperation of the third step and the fourth step.

[0023] In an exemplary embodiment of one aspect of the present invention, the shock absorber may also include an upper joint and a lower joint, wherein the lower end of the upper joint is fixedly connected to the upper end of the outer tube to fix the shock absorber to the upstream drill bit, and the upper end of the lower joint is fixedly connected to the lower end of the force transmission spline shaft to fix the shock absorber to the downstream drill bit.

[0024] In an exemplary embodiment of one aspect of the present invention, the outer cylinder and the force transmission spline cylinder, the anti-drop connecting rod and the piston rod, and the piston rod and the force transmission spline shaft can be fixedly connected by threads.

[0025] In an exemplary embodiment of one aspect of the present invention, the upper dynamic seal assembly may include an elastic retaining ring, a lock nut, a packing box, a scraper ring and at least one group of seals, wherein the packing box is sleeved on the outer wall of the piston rod and forms a seal with the outer wall of the piston rod, the at least one group of seals is arranged between the outer wall of the packing box and the inner wall of the outer tube, the lock nut locks the axial position of the packing box and at least one group of seals, the elastic retaining ring is fixed on the piston rod to axially lock the lock nut, and the scraper ring is arranged on the lock nut to prevent external mud and sand from entering the interior of the shock absorber.

[0026] In an exemplary embodiment of one aspect of the present invention, the lower dynamic seal assembly may include a wear-resistant ring, at least one set of seals, an open bearing, a piston pin and a scraper ring, wherein the at least one set of seals is arranged between the inner wall of the spline outer cylinder and the outer wall of the spline shaft, the wear-resistant ring is arranged on both sides of the at least one set of seals, the open bearing is arranged at the lower end of the at least one set of seals, the piston pin is arranged on the spline outer cylinder and connected to the open bearing, and the scraper ring is arranged under the open bearing to prevent mud and sand from entering the outer wall.

[0027] In an exemplary embodiment of an aspect of the present invention, the at least one set of sealing keys may include a support ring, a V-shaped sealing ring group and a pressure ring, wherein the support ring is used to support the V-shaped sealing ring group and the pressure ring presses the V-shaped sealing ring group.

[0028] Another aspect of the present invention provides a drilling tool assembly, which may include a drilling shock absorber with an anti-drop function as described in any one of the above items.

[0029] In an exemplary embodiment of another aspect of the present invention, the drilling tool assembly may also include an upstream drilling tool and a downstream drilling tool, wherein the upstream drilling tool is directly or indirectly fixedly connected to the upper end of the drilling shock absorber, and the downstream drilling tool is directly or indirectly fixedly connected to the lower end of the drilling shock absorber.

[0030] Compared with the prior art, the beneficial effects of the present invention may include at least one of the following:

[0031] (1) The present invention meets the functional requirements of the air drilling shock absorber for shock absorption and protection of the drill tool assembly during the drilling process;

[0032] (2) The shock absorber of the present invention is provided with two shock absorbing structures. On the one hand, the shock is absorbed by the volume elastic deformation of a large amount of compressible liquid such as silicone oil in the oil chamber; on the other hand, the purpose of shock absorption is achieved by utilizing the damping of compressible liquid such as silicone oil flowing through the spline gap;

[0033] (3) The present invention adopts a new sealing structure, which improves reliability and service life while ensuring the sealing between structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and other objects and features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0035] Figure 1 A schematic structural diagram of a drilling shock absorber with an anti-drop function according to an exemplary embodiment of the present invention is shown;

[0036] Figure 2 Shows Figure 1 An enlarged view of the middle and upper dynamic seal assembly;

[0037] Figure 3 Shows Figure 1 An enlarged view of the middle and lower dynamic seal assembly;

[0038] Figure 4 Shows Figure 1 Schematic diagram of the structure along the CC section.

[0039] Reference numerals:

[0040] 1-outer cylinder, 2-anti-drop connecting rod, 3-oil plug assembly, 4-piston rod, 5-high-pressure oil chamber, 6-O-ring, 7-retaining ring, 8-force transmission spline cylinder, 9-cavity, 10-anti-drop outer cylinder, 11-force transmission spline shaft, 12-elastic retaining ring, 13-scraper ring, 14-V-shaped sealing ring group, 15-support ring, 16-packing box, 17-pressure ring, 18-washer, 19-lock nut, 20-wear-resistant ring, 21-open bearing, 22-piston pin, 23-BS sealing ring, 24-scraper ring, 25-upper joint, 26-lower joint, 27-damping channel, A-upper dynamic seal assembly, B-lower dynamic seal assembly. DETAILED DESCRIPTION

[0041] Hereinafter, the drilling shock absorber with anti-drop function and the drilling tool assembly of the present invention will be described in detail in conjunction with exemplary embodiments.

[0042] It should be noted that “upper”, “lower”, “inner” and “outer” are only for the convenience of description and to constitute a relative orientation or position relationship, and do not indicate or imply that the referred to component must have this specific orientation or position.

[0043] In the first exemplary embodiment of the present invention, the drilling shock absorber with anti-drop function mainly includes an outer cylinder, an anti-drop connecting rod, a piston rod, a force transmission spline cylinder, an anti-drop outer cylinder, a force transmission spline shaft and an upper dynamic seal assembly. Among them, the lower end of the outer cylinder is fixedly connected to the upper end of the force transmission spline cylinder to form the outer shell of the drilling shock absorber. The lower part of the anti-drop connecting rod is fixedly connected to the upper part of the piston rod, and the lower part of the piston rod is fixedly connected to the upper end of the force transmission spline shaft to form the inner cylinder of the drilling shock absorber.

[0044] In this embodiment, the inner cylinder portion of the drilling shock absorber is disposed in the outer shell portion and can undergo relative movement.

[0045] The outer cylinder can limit the displacement of the anti-drop connecting rod in the outer cylinder relative to the outer cylinder downward.

[0046] The anti-drop connecting rod and the piston rod are located in the outer tube, and a high-pressure oil chamber is formed between the outer wall of the piston rod and the inner wall of the outer tube. The volume of the high-pressure oil chamber can change when the inner tube part and the outer tube part move relative to each other, and a compressible liquid is arranged in the high-pressure oil chamber. Here, the drilling shock absorber also includes an oil plug assembly, and the outer tube is provided with a through hole connected to the high-pressure oil chamber, and the oil plug assembly blocks the through hole. For example, the outer wall of the piston rod is recessed inward to form a high-pressure oil chamber with the outer tube, and the diameter of the piston rod located at the upper part of the high-pressure oil chamber is smaller than the diameter of the piston rod located at the lower part of the high-pressure oil chamber. The inner wall of the outer tube is sealed with the outer wall of the piston rod at both ends of the high-pressure oil chamber. In the process of the piston rod moving upward relative to the outer tube in the outer tube, the volume of the high-pressure oil chamber gradually decreases, and the compressible liquid therein is compressed to reduce the axial vibration.

[0047] The force transmission spline shaft is arranged inside the force transmission spline cylinder and connected by splines. The force transmission spline shaft can move axially in the force transmission spline cylinder. The torque of the force transmission spline cylinder can be transmitted to the force transmission spline shaft by arranging the splines.

[0048] The upper dynamic seal assembly is arranged on one side or both sides of the high-pressure oil chamber to form a dynamic seal, namely, the upper and lower ends of the high-pressure oil chamber.

[0049] The anti-drop outer cylinder is arranged on the force transmission spline cylinder and the force transmission spline shaft, and can limit the downward displacement of the force transmission spline shaft relative to the force transmission spline cylinder.

[0050] In this exemplary embodiment, the shock absorber may also include a damping channel and a lower dynamic seal assembly, the damping channel may be arranged between the inner wall of the force transmission spline cylinder and the outer wall of the force transmission spline shaft, the lower dynamic seal assembly is arranged on one side or both sides of the damping channel to form a dynamic seal, the damping channel is filled with a compressible liquid, and the compressible liquid flows in the damping channel to form nonlinear damping for shock absorption. Further, the outer wall of the force transmission spline shaft has protruding splines evenly distributed in the radial direction, the inner wall of the force transmission spline cylinder is provided with a spline groove that cooperates with the spline, and the damping channel is arranged in the spline groove.

[0051] In this exemplary embodiment, a first step protruding outward may be provided on the inner wall of the outer cylinder, and a second step cooperating with the first step may be provided on the upper outer wall of the anti-drop connecting rod, so that the downward displacement of the anti-drop connecting rod in the outer cylinder is limited by the cooperation of the first step and the second step.

[0052] In this exemplary embodiment, the lower end of the anti-drop outer cylinder can be fixedly connected to the force transmission spline shaft, and a third step protruding outward can be provided on the outer wall of the force transmission spline cylinder. The anti-drop outer cylinder is provided with a fourth step that cooperates with the third step. The downward displacement of the force transmission spline shaft relative to the force transmission spline cylinder is limited by the cooperation of the third step and the fourth step.

[0053] In this exemplary embodiment, the shock absorber may also include an upper joint and a lower joint, wherein the lower end of the upper joint is fixedly connected to the upper end of the outer tube to fix the shock absorber to the upstream drill bit, and the upper end of the lower joint is fixedly connected to the lower end of the force transmission spline shaft to fix the shock absorber to the downstream drill bit.

[0054] In this exemplary embodiment, the outer cylinder and the force transmission spline cylinder, the anti-drop connecting rod and the piston rod, and the piston rod and the force transmission spline shaft can be fixedly connected by threads. However, the present invention is not limited thereto, and other fixing methods are also possible.

[0055] In this exemplary embodiment, the upper dynamic seal assembly may include an elastic retaining ring, a lock nut, a packing box, a scraper ring and at least one group of seals, wherein the packing box is sleeved on the outer wall of the piston rod and forms a seal with the outer wall of the piston rod, the at least one group of seals is arranged between the outer wall of the packing box and the inner wall of the outer tube, the lock nut locks the axial position of the packing box and at least one group of seals, the elastic retaining ring is fixed on the piston rod to axially lock the lock nut, and the scraper ring is arranged on the lock nut to prevent external mud and sand from entering the interior of the shock absorber.

[0056] In this exemplary embodiment, the lower dynamic seal assembly may include a wear-resistant ring, at least one set of seals, an open bearing, a piston pin and a scraper ring, wherein the at least one set of seals is arranged between the inner wall of the spline outer cylinder and the outer wall of the spline shaft, the wear-resistant ring is arranged on both sides of the at least one set of seals, the open bearing is arranged at the lower end of the at least one set of seals, the piston pin is arranged on the spline outer cylinder and connected to the open bearing, and the scraper ring is arranged under the open bearing to prevent mud and sand from entering the outer wall.

[0057] In this exemplary embodiment, the at least one set of sealing keys may include a support ring, a V-shaped sealing ring group and a pressure ring, wherein the support ring is used to support the V-shaped sealing ring group and the pressure ring presses the V-shaped sealing ring group.

[0058] Figure 1 A schematic structural diagram of a drilling shock absorber with an anti-drop function according to an exemplary embodiment of the present invention is shown; Figure 2 Shows Figure 1 An enlarged view of the middle and upper dynamic seal assembly; Figure 3 Shows Figure 1 An enlarged view of the middle and lower dynamic seal assembly; Figure 4 Shows Figure 1 Schematic diagram of the structure along the CC section.

[0059] In a second exemplary embodiment of the present invention, Figure 1As shown in the figure, the drilling shock absorber with anti-shock function and anti-drop function mainly includes an outer cylinder 1, an anti-drop connecting rod 2, a piston rod 4, a force transmission spline cylinder 8, an anti-drop outer cylinder 10, a force transmission spline shaft 11 and an upper dynamic sealing assembly A.

[0060] In this embodiment, the outer cylinder 1 and the force transmission spline cylinder 8, the anti-drop connecting rod 2 and the piston rod 4, and the piston rod 4 and the force transmission spline shaft 11 are fixedly connected by threads.

[0061] In this embodiment, the shock absorber is divided into an outer shell and an inner cylinder. The outer shell is composed of the lower end of the outer cylinder 1 and the upper end of the force transmission spline cylinder 8 fixedly connected. The inner cylinder is composed of the lower part of the anti-drop connecting rod 2 and the upper part of the piston rod 4 fixedly connected, and the lower part of the piston rod 4 and the upper part of the force transmission spline shaft 11 fixedly connected. The inner cylinder is arranged in the outer shell, and the inner cylinder can move axially relative to the outer shell.

[0062] In this embodiment, the displacement of the anti-drop connecting rod 2 in the outer cylinder 1 relative to the outer cylinder 1 is limited by the outer cylinder 1. The anti-drop connecting rod 2 and the piston rod 4 are arranged in the outer cylinder 1, and the outer wall of the piston rod 4 is recessed inward to form a high-pressure oil chamber 5 with the inner wall of the outer cylinder 1. The volume of the high-pressure oil chamber 5 increases with the relative movement of the inner cylinder part and the outer cylinder part (i.e. Figure 1 The high-pressure oil chamber 5 is filled with a compressible liquid. Here, the compressible liquid can be silicone oil or a liquid with similar properties to silicone oil. As the outer wall of the piston rod moves upward relative to the outer tube 1, the volume of the high-pressure oil chamber 5 decreases, and the compressible liquid therein is compressed. Here, shock absorption is achieved by the elastic deformation of the volume of the compressible liquid in the high-pressure oil chamber. Here, the upper end of the force transmission spline cylinder 8 is not connected to the lower end of the piston rod 4, and the two are separable. Figure 1 As shown in the figure, an O-ring 6 and a retaining ring 7 are also arranged between the upper end of the force transmission spline cylinder 8 and the lower end of the piston rod 4 to prevent the force transmission spline cylinder from directly hitting the piston rod when the inner cylinder part moves upward in the outer cylinder, thereby playing a buffering role.

[0063] In this embodiment, the upper dynamic seal assembly A is arranged on one side or both sides of the high-pressure oil chamber 5 to form a dynamic seal.

[0064] like Figure 2 As shown in FIG. 1 , the upper dynamic seal assembly includes an elastic retaining ring 12, a lock nut 19, a packing box 16, a scraper ring 13 and at least one set of sealing members.

[0065] The packing box 16 is sleeved on the outer wall of the piston rod 4 and is provided with a raised step to contact the inner wall of the outer tube. The inner wall of the packing box forms a seal with the outer wall of the piston rod 4. At least one set of sealing components is provided between the outer wall of the packing box 16 and the inner wall of the outer tube 1. For example, Figure 2As shown in FIG. 1 , two sets of sealing components are arranged between the outer wall of the packing box 16 and the inner wall of the outer cylinder. The packing box 16 and at least one set of sealing components are locked in axial position by the lock nut 19. The elastic retaining ring 12 is fixed to the piston rod 4 and locks the lock nut 19 axially. The scraper ring 13 is arranged on the lock nut 19, and the scraper ring 13 is used to prevent external mud and sand from entering the shock absorber.

[0066] Further, the upper dynamic seal assembly may also include a gasket 18. The gasket 18 is arranged on the right end of the packing box 16 in contact with the outer wall of the piston rod. Here, the upper dynamic seal assembly can effectively meet the sealing requirements when the upper high-pressure oil chamber moves axially.

[0067] In this embodiment, if Figure 1 and 4 As shown in , a force transmission spline shaft 11 is arranged inside the force transmission spline cylinder 8. The force transmission spline cylinder 8 and the force transmission spline shaft 11 are connected by a spline. During the drilling process, the force transmission spline cylinder 8 and the force transmission spline shaft 11 transmit the rotational torque through the spline connection.

[0068] In this embodiment, if Figure 1 As shown in , the anti-drop outer cylinder 10 is arranged between the force transmission spline cylinder 8 and the force transmission spline shaft 11, and limits the relative displacement of the force transmission spline shaft 11 relative to the downward movement of the force transmission spline cylinder 8. Specifically, as Figure 1 As shown, the outer cylinder 1 is provided with a first step, the first step protrudes outward, and the anti-drop connecting rod 2 is provided with a second step, the second step cooperates with the first step. The downward displacement of the anti-drop connecting rod 2 in the outer cylinder 1 is limited by the first step and the second step.

[0069] In addition, a third step is provided on the outer wall of the force transmission spline cylinder 8, and the third step protrudes outward, and a fourth step is provided on the anti-drop outer cylinder 10, and the fourth step cooperates with the third step. The downward displacement of the force transmission spline shaft 11 relative to the force transmission spline cylinder 8 is limited by the third step and the fourth step. Here, the first step, the second step, the third step, and the fourth step can be annular protrusions provided on the inner wall or the outer wall of the cylinder.

[0070] In this embodiment, if Figure 1As shown, the shock absorber is also provided with a damping channel and a lower dynamic sealing assembly B. The damping channel is arranged between the inner wall of the force transmission spline cylinder 8 and the outer wall of the force transmission spline shaft 11. The lower dynamic sealing assembly B is arranged on one side or both sides of the damping channel and forms a seal. The damping channel is filled with a compressible liquid, and the compressible liquid flows in the damping channel to form nonlinear damping, which plays a shock absorbing role. In addition, a cavity 9 for accommodating a compressible liquid can be formed between the inner wall of the force transmission spline cylinder 8 and the outer wall of the force transmission spline shaft 11. The volume of the cavity 9 decreases as the force transmission spline shaft moves upward relative to the force transmission spline cylinder. The cavity is connected to the damping channel to provide compressible liquid to the resistance channel during the movement. Here, an oil plug assembly is also provided on the force transmission spline cylinder, and the oil plug assembly blocks the through hole on the force transmission spline cylinder. Here, the compressible liquid in the cavity is the same as that in the high-pressure oil chamber. Specifically, as Figure 4 As shown in the figure, the outer wall of the force transmission spline shaft 11 is provided with evenly distributed raised splines, the inner wall of the force transmission spline cylinder 8 is provided with spline grooves matching the splines, and the damping channel 27 is provided in the spline grooves and on the splines.

[0071] In this embodiment, if Figure 1 As shown in , the drilling shock absorber is also provided with an upper joint 25 and a lower joint 26. The lower end of the upper joint 25 is fixedly connected to the upper end of the outer tube 1. The upper end of the lower joint 26 is fixedly connected to the lower end of the force transmission spline shaft 11. The drilling shock absorber is connected to the upstream drilling tool through the upper joint 25 and is connected to the downstream drilling tool through the lower joint 26.

[0072] In this embodiment, if Figure 3 As shown in the figure, the lower dynamic seal assembly includes a wear ring 20, at least one set of seals, an open bearing 21, a piston pin 22 and a scraper ring 24. The wear ring 20 is arranged at both ends of at least one set of seals, and the open bearing 21 is arranged at the lower end of the at least one set of seals ( Figure 3 The piston pin 22 is arranged on the force transmission spline cylinder 8, and the piston pin 22 is connected to the open bearing bush 21. The scraper ring 24 is arranged on the right end of the open bearing bush 21 to prevent the mud and sand on the outer wall from entering. Specifically, the lower dynamic seal assembly also includes a BS seal ring 23, which is arranged on the force transmission spline shaft 11 and symmetrically arranged on both sides of the open bearing bush 21.

[0073] Here, at least one set of seals in the upper dynamic seal assembly and the lower dynamic seal assembly includes a support ring 15, a V-shaped seal ring group 14 and a pressure ring 17. The support ring 15 supports the V-shaped seal ring group 14, and the pressure ring 17 presses the V-shaped seal ring group 14.

[0074] In a third exemplary embodiment of the present invention, the drilling tool assembly may include the drilling shock absorber with an anti-drop function as described in the first or second exemplary embodiment.

[0075] In this exemplary embodiment, the drilling tool assembly may also include an upstream drilling tool and a downstream drilling tool, wherein the upstream drilling tool is directly or indirectly fixedly connected to the upper end of the drilling shock absorber, and the downstream drilling tool is directly or indirectly fixedly connected to the lower end of the drilling shock absorber. Here, the lower end of the upstream drilling tool may be directly fixedly connected to the upper end of the drilling shock absorber, or may be indirectly fixedly connected to the upper end of the drilling shock absorber through tools such as drill collars or centralizers. Similarly, the downstream drilling tool may be directly fixedly connected to the lower end of the drilling shock absorber, or may be indirectly fixedly connected to the lower end of the drilling shock absorber through tools such as drill collars or centralizers.

[0076] In summary, the advantages proposed by the present invention include at least one of the following:

[0077] (1) The shock absorber of the invention is designed with internal and external anti-drop devices to protect the weak parts of the shock absorber from falling;

[0078] (2) The invention is particularly suitable for use in connection with an air hammer during gas drilling, and can effectively protect the upper drill string and the lower air hammer;

[0079] (3) The shock absorber of the invention has a large shock absorption range, a wide stiffness range, a simple and reliable structure, and is easy to maintain. It can effectively reduce drilling costs and improve drilling work efficiency.

[0080] Although the present invention has been described above by combining with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined in the claims.

Claims

1. A drilling shock absorber with anti-drop function, characterized in that: The drilling shock absorber comprises an outer cylinder, an anti-drop connecting rod, a piston rod, a force transmission spline cylinder, an anti-drop outer cylinder, a force transmission spline shaft and an upper dynamic sealing assembly, wherein: The lower end of the outer cylinder is fixedly connected to the upper end of the force transmission spline cylinder to form the outer shell part of the shock absorber; the lower part of the anti-drop connecting rod and the upper part of the piston rod are fixedly connected, and the lower part of the piston rod and the upper part of the force transmission spline shaft are fixedly connected to form the inner cylinder part of the shock absorber; the inner cylinder part is arranged in the outer shell part and can undergo relative movement, wherein the outer cylinder can limit the downward displacement of the anti-drop connecting rod relative to the outer cylinder; the anti-drop connecting rod and the piston rod are located in the outer cylinder and a high-pressure oil chamber is formed between the outer wall of the piston rod and the inner wall of the outer cylinder, the volume of the high-pressure oil chamber can change when the inner cylinder part and the outer cylinder part undergo relative movement, and a compressible liquid is arranged in the high-pressure oil chamber; the force transmission spline shaft is arranged inside the force transmission spline cylinder and is connected by a spline to transmit torque; the upper dynamic sealing assembly is arranged on one side or both sides of the high-pressure oil chamber to form a seal; the anti-drop outer cylinder is arranged on the force transmission spline cylinder and the force transmission spline shaft and can limit the downward displacement of the force transmission spline shaft relative to the force transmission spline cylinder.

2. The drilling shock absorber with anti-drop function according to claim 1, characterized in that: The shock absorber also includes a damping channel and a lower dynamic sealing assembly. The damping channel is arranged between the inner wall of the force transmission spline cylinder and the outer wall of the force transmission spline shaft. The lower dynamic sealing assembly is arranged on one side or both sides of the damping channel to form a seal. The damping channel is filled with a compressible liquid. The compressible liquid flows in the damping channel to form nonlinear damping for shock reduction.

3. The drilling shock absorber with anti-drop function according to claim 2, characterized in that: The outer wall of the force transmission spline shaft is provided with protruding splines evenly distributed in the radial direction, the inner wall of the force transmission spline cylinder is provided with a spline groove matched with the splines, and the damping channel is arranged in the spline groove.

4. The drilling shock absorber with anti-drop function according to claim 1, characterized in that: A first step protruding outward is arranged on the inner wall of the outer cylinder, and a second step cooperating with the first step is arranged on the upper outer wall of the anti-drop connecting rod. The downward displacement of the anti-drop connecting rod in the outer cylinder is limited by the cooperation of the first step and the second step.

5. The drilling shock absorber with anti-drop function according to claim 1, characterized in that: The lower end of the anti-drop outer cylinder is fixedly connected to the force transmission spline shaft, a third step protruding outward is provided on the outer wall of the force transmission spline cylinder, and a fourth step cooperating with the third step is provided on the anti-drop outer cylinder. The downward displacement of the force transmission spline shaft relative to the force transmission spline cylinder is limited by the cooperation of the third step and the fourth step.

6. The drilling shock absorber with anti-drop function according to claim 1, characterized in that: The shock absorber also includes an upper joint and a lower joint, the lower end of the upper joint is fixedly connected to the upper end of the outer tube to fix the shock absorber to the upstream drilling tool, and the upper end of the lower joint is fixedly connected to the lower end of the force transmission spline shaft to fix the shock absorber to the downstream drilling tool.

7. The drilling shock absorber with anti-drop function according to claim 1, characterized in that: The outer cylinder and the force transmission spline cylinder, the anti-drop connecting rod and the piston rod, and the piston rod and the force transmission spline shaft are fixedly connected through threads.

8. The drilling shock absorber with anti-drop function according to claim 1, characterized in that: The upper dynamic seal assembly includes an elastic retaining ring, a lock nut, a packing box, a scraper ring and at least one group of seals, wherein the packing box is sleeved on the outer wall of the piston rod and forms a seal with the outer wall of the piston rod, the at least one group of seals is arranged between the outer wall of the packing box and the inner wall of the outer tube, the lock nut locks the axial position of the packing box and at least one group of seals, the elastic retaining ring is fixed on the piston rod to axially lock the lock nut, and the scraper ring is arranged on the lock nut to prevent external mud and sand from entering the inside of the shock absorber.

9. The drilling shock absorber with anti-drop function according to claim 2, characterized in that: The lower dynamic seal assembly includes a wear-resistant ring, at least one set of seals, an open bearing, a piston pin and a scraper ring, wherein the at least one set of seals is arranged between the inner wall of the spline outer cylinder and the outer wall of the spline shaft, the wear-resistant ring is arranged on both sides of the at least one set of seals, the open bearing is arranged at the lower end of the at least one set of seals, the piston pin is arranged on the spline outer cylinder and connected to the open bearing, and the scraper ring is arranged under the open bearing to prevent mud and sand from entering the outer wall.

10. The drilling shock absorber with anti-drop function according to claim 8 or 9, characterized in that: The at least one group of sealing components comprises a support ring, a V-shaped sealing ring group and a pressure ring, wherein the support ring is used to support the V-shaped sealing ring group, and the pressure ring presses the V-shaped sealing ring group.

11. A drilling tool assembly, characterized in that: The drilling tool assembly includes the drilling shock absorber with an anti-drop function as claimed in any one of claims 1 to 10.

12. The drilling tool assembly according to claim 11, characterized in that: The drilling tool assembly also includes an upstream drilling tool and a downstream drilling tool. The upstream drilling tool is directly or indirectly fixedly connected to the upper end of the drilling shock absorber, and the downstream drilling tool is directly or indirectly fixedly connected to the lower end of the drilling shock absorber.

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