Drill bit assembly capable of prolonging service life

Abstract

The invention discloses a drill bit assembly capable of prolonging the service life, and relates to the technical field of well drilling equipment, the drill bit assembly comprises a shock absorber connected to the drill bit assembly in series, the shock absorber comprises a first column section and a second column section, the lower end of the first column section is embedded into the upper end of the second column section, and the first column section is provided with a spline shaft section in key fit with the second column section; the belleville spring set is arranged in a center hole of the second column section, the belleville spring set is configured in the mode that the lower end of the first column section directly faces the upper end of the belleville spring set, the first column section provides axial force for the second column section through the belleville spring set, an annular cavity is formed in the side wall of the second column section and is coaxial with the belleville spring set, and the belleville spring set is arranged in the annular cavity. According to the scheme, the working temperature of the belleville springs can be reduced, and therefore the purposes that the rigidity of the belleville springs is guaranteed, the situation that the friction coefficient is out of control and even the belleville springs are stuck is avoided, and the service life of the drill bit and the service life of the drill bit assembly are prolonged are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drilling equipment, in particular to a drill bit assembly with prolonged service life. BACKGROUND

[0002] In the process of rotary drilling, stick-slip effect is a common vibration phenomenon in the process of drilling with a drill bit, which is mainly manifested as a dramatic periodic change in the rotation speed of the drill bit, including a temporary complete stop of the rotation of the drill bit (stick phase), a sudden acceleration of the rotation of the drill bit (slip phase), and a repeated cycle of the above states, which has an impact on drilling tools, including but not limited to drill string fatigue cracking, drill bit damage, reduced drilling efficiency, increased difficulty in directional control, equipment wear, etc., and is a harmful phenomenon in the process of rotary drilling.

[0003] In the prior art, measures commonly used to alleviate and suppress stick-slip effect include increasing drilling speed, reducing drilling pressure, and using shock absorbers to optimize drill tool structure, especially in deep wells, hard formations and directional wells in slip drilling, stick-slip effect is a key problem that needs special attention and response. As for the use of shock absorbers to optimize drill tool structure, its essence is mainly used to solve the problem of axial vibration, and the specific principle is to reduce the size of instantaneous impact of the drill tool by allowing the core structure of the elastic element to undergo controllable compression deformation and absorbing impact energy during the working process, so as to isolate the impact and vibration from the bottom of the well and prevent them from propagating upward. The specific scheme is provided in the prior art patent document CN202411702208.8. As provided in the technical solution of the patent document with the application number CN202311337766.4, a disc spring is used as the elastic element, and the applicant believes that by using the energy storage mechanism and friction energy dissipation mechanism of the disc spring, the effect of smoothing the axial impact load can be achieved, and compared with the use of a coil spring, the disc spring can significantly attenuate the amplitude of axial vibration.

[0004] The drilling shock absorber used in the prior art usually has a relatively long length, and using a disc spring as the elastic element of the drilling shock absorber can effectively shorten the length of the shock absorber, and compared with relying on internal friction of the material to dissipate energy (using a coil spring as the elastic element), the disc spring can dissipate vibration energy more efficiently through more intense friction.

[0005] In summary, further optimizing the structural design of the disc spring-based shock absorber to further ensure its reliability is of great significance to ensuring the efficiency of drilling operations, the service life of the drill bit assembly, and the quality of the drilling. SUMMARY

[0006] In view of the above-mentioned problems of optimizing the disc spring-based shock absorber, the present application provides a drill bit assembly with prolonged service life, and the structural design of the present application is beneficial to reducing the working temperature of the disc spring, thereby achieving the purposes of ensuring the stiffness of the disc spring, avoiding the out-of-control of the friction coefficient and even the disc spring jamming, and prolonging the service life of the drill bit and the drill bit assembly.

[0007] In view of the above-mentioned problems, the present application provides a drill bit assembly with prolonged service life, which solves the problems through the following technical points: a drill bit assembly with prolonged service life includes a shock absorber connected in series on the drill bit assembly, the shock absorber includes a first column segment and a second column segment, the lower end of the first column segment is embedded in the upper end of the second column segment, and the first column segment has a spline shaft segment that is keyed with the second column segment; further including a disc spring group arranged in the central hole of the second column segment, the disc spring group is configured such that the lower end of the first column segment is opposite to the upper end of the disc spring group, and the first column segment provides an axial force to the second column segment through the disc spring group, the side wall of the second column segment is provided with an annular cavity, the annular cavity is coaxial with the disc spring group, and the disc spring group is partially or entirely located within the wrapping area of the annular cavity on the second column segment.

[0008] In use, the present application is connected in series on the drill string of the drilling assembly, and the specific connection position on the drill string is determined according to the structure of the drill string and the protection object, for example, it is arranged above the drill collar and above the downhole measurement tool, in the specific structure, the disc spring group serves as the elastic element of the shock absorber, the disc spring group is a laminated structure formed by stacking multiple disc springs, the first column segment is slidingly connected with the second column segment, the first column segment provides torque to the second column segment through the spline shaft segment, and the second column segment provides support to the first column segment through the disc spring group, when axial vibration occurs on the drill string, the disc spring group is stretched and contracted to absorb impact energy, and the first column segment and the second column segment slide relative to each other, thereby achieving the purposes of isolating the impact and vibration from the bottom of the well from propagating upward and reducing the size of the instantaneous impact of the drilling tool.

[0009] The present application adopts the disc spring group as the elastic element of the shock absorber, the disc spring group is a kind of elastic element with high equivalent damping ratio, in the stretching and contracting process, the corresponding friction surface efficiently consumes energy at the same time, if the generated heat cannot be efficiently transferred to the surrounding environment (such as drilling fluid), the disc spring group will have a high working temperature, which is not conducive to maintaining the stiffness and friction coefficient of the disc spring group, and even causes the disc spring group to jam, the present application provides an annular cavity arranged in the side wall of the second column segment, the annular cavity is used to contain heat-conducting oil as the heat-conducting agent, thereby providing better heat dissipation conditions for the heat generated by the disc spring group and ensuring the thermal stability of the disc spring group, thereby improving the service life of the drill bit and the drill bit assembly.

[0010] Specifically, the existing disc spring set is generally installed in the outer cylinder (second column segment) with a solid side wall, and the heat generated by the disc spring set is mainly transmitted outward by the side wall heat conduction. Although the metal heat conductivity of the second column segment side wall is usually much higher than that of the heat conducting oil, the actual working condition of the shock absorber is that it rotates with the drill pipe, and under the action of the stick-slip effect caused by the change of geological resistance and the fluctuation of drill pipe power, the shock absorber has speed fluctuation during the whole drilling process. When the speed of the shock absorber changes, the heat conducting oil in the annular cavity lags behind the movement of the second column segment due to inertia, that is, the heat conducting oil in the annular cavity will undergo strong shear flow and form transient turbulent flow, forcing the mixing of the cold and hot oil layers on the inside and outside of the annular cavity (under the action of centrifugal force, high-density cold oil gathers on the outside of the annular cavity, and low-density hot oil gathers on the inside of the annular cavity). That is, the heat conducting oil in the annular cavity is repeatedly stirred during the rotation of the shock absorber with the drill pipe, avoiding the locking of hot oil on the inside of the annular cavity, so that the oil temperature of the heat conducting oil at each position in the annular cavity has the characteristics of relative uniformity. As for the heat generated by the disc spring set to be transmitted to the drilling fluid, after the annular cavity is set and the heat conducting oil is set in the annular cavity, under the actual non-uniform speed rotation condition of the shock absorber, when the heat conducting oil moves relative to the inner wall and the outer wall of the annular cavity, the heat transfer coefficient occurring at the two interfaces is much higher than that of solid metal heat conduction. That is, the heat generated by the disc spring set can be efficiently transmitted from the inner wall of the annular cavity to the heat conducting oil, and the heat of the heat conducting oil can be efficiently transmitted to the outer wall of the annular cavity. At the same time, the turbulent mixing of the heat conducting oil itself makes the temperature of the heat conducting oil at different positions in the annular cavity have the characteristics of relative uniformity. In this way, for the heat generated by the disc spring set to be transmitted outward, the heat conducting oil acts as a heat carrier, and the flow of the heat conducting oil in the annular cavity can efficiently transmit heat from the inner wall of the annular cavity to the outer wall of the annular cavity in the form of convective heat transfer. That is, the lower heat conductivity of the heat conducting oil relative to metal does not affect the heat transmission from the inner wall of the annular cavity to the outer wall of the annular cavity, solving the problems of radial temperature gradient and inner wall heat accumulation existing in the traditional solid side wall. Compared with the traditional disc spring set with a solid side wall outside the outer cylinder, the present scheme forms a heat conducting oil cavity around the disc spring set through the annular cavity, that is, even if the second column segment with the annular cavity is designed to be thicker (the sum of the thicknesses of the inner and outer metal side walls of the annular cavity is 140% of the thickness of the solid side wall, and the thickness of the inner metal side wall of the annular cavity is less than that of the outer metal side wall), under the close drilling condition, the working temperature of the disc spring set can be reduced from a maximum of 140°C to a maximum of 110°C.

[0011] As a person skilled in the art, the above coaxial arrangement aims to configure the center of gravity of the second column segment so that the center of gravity of the second column segment is located on its axis as much as possible, and the above thickening of the second column segment with an annular cavity is: relative to the thickening of the case where the side wall of the second column segment is arranged as a solid side wall, the purpose is to ensure the mechanical properties of the second column segment arranged as a double-layer structure, and the metal side wall outside the annular cavity (as the outer side wall) is thicker than the metal side wall inside the annular cavity (as the inner side wall), aiming at the outer side wall which needs to bear contact load from the outside during work, so as to provide a technical solution with stronger strength reserve. At the same time, as a person skilled in the art, when the second column segment is thickened, the total thermal resistance of the metal wall will increase to a certain extent during the process of heat transfer from the inside of the second column segment to the outside. The main reason for the present solution to reduce the working temperature of the disc spring set is that: during the stretching and contraction of the disc spring set, according to the specific friction position, local hot spots will be formed in the disc spring set arrangement area of the shock absorber, that is, the temperature distribution of each position of the inner wall of the inner side wall is uneven. The role of the heat conducting oil is to efficiently transfer heat to each position of the inner wall of the outer side wall by flowing in the annular cavity, so that the temperature distribution of each position of the inner wall of the outer side wall and the inner and outer walls of the outer side wall is more uniform, that is, the heat conducting oil forms an efficient heat conduction channel between the inner and outer walls of the annular cavity in the form of a heat carrier, improves the utilization rate of the heat dissipation area of the outer wall of the second column segment in the form of improving the utilization rate of the temperature difference, and achieves the purpose of improving the heat transfer capacity of the heat generated by the disc spring set as a whole.

[0012] On the other hand, from the perspective of heat storage, when the present solution uses heat conducting oil with specific heat capacity greater than that of the metal side wall, the heat capacity of the heat conducting oil can be used to buffer the local high temperature of the disc spring set caused by transient peak heat generation.

[0013] On the other hand, from the perspective of heat dissipation, the heat generated by the disc spring set is transferred from the inner side wall to the heat conducting oil, and since the inner side wall can be arranged to be thinner than the outer side wall, and the heat conducting oil can efficiently absorb the heat on the inner side wall by flowing relative to the inner side wall, the heat conducting oil can be used to reduce the temperature difference of each position of the disc spring set by efficiently absorbing heat, thereby avoiding local high temperature.

[0014] In a specific application example, although the heat generated by the heat conducting oil in the annular cavity and the annular cavity friction is less than 5% of the heat generated by the disc spring set friction, in order to reduce this part of the heat, the preferred application is to use low-viscosity heat conducting oil, such as nano heat conducting oil, and at the same time, the annular cavity has a smooth inner wall shape.

[0015] In one specific embodiment, it further includes a floating ring arranged in the annular cavity, the floating ring is a hollow annular structure, and the axis of the floating ring is coaxial with the axis of the annular cavity; The through hole is provided with a plug for plugging the through hole, and when the plug is installed in the through hole, the annular cavity is closed as a closed cavity.

[0016] The above scheme aims to solve the following problem: for a shock absorber, it is not suitable to set an oil passage for realizing circulation of the heat conducting oil in the annular cavity, and therefore in specific application, a preferable mode is to set the annular cavity as a closed cavity, i.e. to form a closed oil cavity containing the heat conducting oil. In this application, if the heat conducting oil fills the annular cavity, the pressure increase in the annular cavity caused by temperature rise of the heat conducting oil can cause the annular cavity to rupture or even explode. When the heat conducting oil does not fill the annular cavity so that there is an air gap in the annular cavity, the redistribution (shaking) of the heat conducting oil in the annular cavity during the vibration of the shock absorber will cause the position of the center of gravity of the second column segment to change in the radial direction, which is not conducive to the vibration control of the drill string. Based on the above, a technical scheme is provided for controlling the pressure change in the annular cavity based on the floating ring and avoiding or reducing the redistribution of the heat conducting oil in the annular cavity. Specifically, the floating ring occupying part of the space of the annular cavity, when the annular cavity is filled with the heat conducting oil through the through hole, the floating ring balances the internal pressure in the annular cavity by synchronously expanding or contracting when the heat conducting oil expands or contracts due to temperature change, and since the floating ring is used to balance the internal pressure in the annular cavity, it is not necessary to reserve an air gap at the upper end of the annular cavity to accommodate the expansion or contraction of the heat conducting oil. During the vibration of the shock absorber, the redistribution of the heat conducting oil in the annular cavity can be effectively avoided, thereby achieving the purpose of facilitating the vibration control of the drill string. The through hole serves as both the heat conducting oil injection hole and the exhaust hole of the annular cavity, and after the oil injection is completed, the through hole is closed by the plug so that the annular cavity is closed as a closed cavity.

[0017] In one specific embodiment, the floating ring is any one of the following structures: The side wall of the floating ring comprises an outer layer of fabric and an inner layer of rubber, and the inner side of the outer layer is attached to the outer side of the inner layer; The side wall of the floating ring is a composite structure in which rubber is impregnated in the fabric gap; The number of the through holes is 2, and each through hole is provided with a plug.

[0018] In the above scheme, the side wall of the floating ring formed by the fabric layer and the rubber layer can be elastically deformed to adapt to the expansion or compression of the floating ring when the pressure in the annular cavity changes, the rubber layer is used to form a closed hollow cavity inside the floating ring to adapt to the expansion or compression of the floating ring, and the fabric layer serves as a wear-resistant protective layer outside the rubber layer to ensure the effective service life of the floating ring under the friction with the wall of the annular cavity. In the implementation mode of the side wall of the floating ring being a composite structure in which rubber is impregnated in the fabric gap, the rubber is used to form the hollow cavity inside the floating ring, and the fabric is used to ensure the wear resistance of the side wall of the floating ring. The number of the through holes is set to realize that one of the through holes is used as an oil injection hole and the other is used as an exhaust hole, so as to improve the oil injection efficiency of the annular cavity and reduce the control difficulty of the air gap formed in the annular cavity.

[0019] In one specific embodiment, the number of the floating rings is multiple.

[0020] Regarding the setting of the number of the floating rings, it is intended to realize that, for the same volume of the hollow cavity, by setting the number of the floating rings to be multiple, the cross-sectional size of a single floating ring can be smaller, and the local deformation resistance of each floating ring is stronger, so as to reduce the influence of the local deformation of the floating ring on the distribution of the heat conducting oil.

[0021] In one specific embodiment, the outer wall of the first column segment is provided with a clamping groove extending along the length direction of the first column segment, and further comprises a locking bolt threadedly connected to the second column segment, and the locking bolt is partially embedded in the clamping groove.

[0022] The above scheme is that, in the drilling process, the first column segment provides pressure for the second column segment through the disc spring set to maintain the drilling pressure of the drill bit, and when the drill pipe is lifted or lowered, the clamping groove and the locking bolt are used to prevent the second column segment from sliding off the first column segment. Specifically, when the second column segment falls relative to the first column segment to the lower end groove wall of the clamping groove where the locking bolt is supported, the second column segment is hung on the groove wall through the locking bolt, and the clamping groove in the strip structure is used to realize that the locking bolt does not prevent the relative sliding of the first column segment and the second column segment during the stretching and deformation of the disc spring set.

[0023] In one specific embodiment, further comprising a third column segment threadedly connected to the lower end of the second column segment, and the second column segment and the third column segment are both provided with annular cavities, and the annular cavities of the two are connected in a butt joint manner. The lower end of the disc spring set is supported on the end face of the third column segment.

[0024] The above scheme is that the upper end of the third column segment is threadedly connected with the lower end of the second column segment to provide bottom support for the disc spring set through the upper end face of the third column segment, and the volume of the annular cavity is further expanded by the third column segment to transfer heat in the heat conducting oil in the annular cavity to the larger heat dissipation structure outside the annular cavity, so as to increase the heat dissipation area and promote the reduction of the working temperature of the disc spring set.

[0025] In a specific embodiment, the upper end of the third column segment is provided with a central pipe which is embedded in the central hole of the second column segment, and the disc spring set is sleeved outside the central pipe; The side wall of the second column segment includes an outer side wall and an inner side wall which are both cylindrical structures, the annular cavity is formed between the outer side wall and the inner side wall, the upper end of the third column segment is threadedly connected with the outer side of the lower end of the outer side wall, the lower end of the inner side wall abuts against the end face of the third column segment, and a sealing ring is arranged between the lower end of the inner side wall and the end face of the third column segment.

[0026] In the above scheme, the central pipe serves as a structure for restricting the central hole of the disc spring set, aiming to facilitate the form retention of the disc spring set and strengthen the role of the disc spring set in consuming energy through friction. The structure of the second column segment and the cooperation relationship with the third column segment are as follows: the space of the second column segment for forming the annular cavity is an annular groove which surrounds the central hole of the second column segment and is formed between the outer side wall and the inner side wall. When the second column segment is connected with the third column segment, the annular groove on the second column segment is butted against the annular groove on the third column segment to form a complete annular cavity. The sealing ring is used to prevent radial leakage at the position where the inner side wall abuts against the end face of the third column segment, so that the heat conducting oil can be stably enclosed in the annular cavity. The above scheme is a technical scheme with simple structure, convenient processing and manufacturing, and assembly.

[0027] In a specific embodiment, the outer side wall is welded to the second column segment or the inner side wall is welded to the second column segment; and the central pipe is welded to the third column segment.

[0028] The above scheme is that the main body structures of the second column segment and the third column segment can be integrally formed, and the complete part manufacturing is completed by welding based on the corresponding main body structures. In specific application, if the outer side wall is welded to the second column segment, the post-weld heat treatment is performed on the corresponding girth weld to ensure the service life of the second column segment, a reinforcing ring is used to locally reinforce the girth weld area, and then the post-weld heat treatment is performed on the corresponding welding position.

[0029] In a specific embodiment, the upper end of the central pipe is inserted into the central hole of the first column segment.

[0030] In the above scheme, the fit between the central tube and the first column segment is used to enhance the coaxiality retention capability of the first and third column segments. By increasing the contact area through the contact between the second and first column segments at the spline shaft segment position and the contact between the third and first column segments at the upper end of the central tube, the wear rate occurring at local positions (spline shaft segment position and upper end of central tube position) during the relative sliding of the first and second / third column segments is solved.

[0031] In one specific embodiment, as a particular application, the drill bit assembly includes a drill rod and a drill bit, and the shock absorber is connected in series between the drill rod and the drill bit via a first column segment and a second column segment.

[0032] The present invention has the following beneficial effects: This solution addresses the issue of disc spring assemblies used as elastic elements in shock absorbers. If the heat generated by the corresponding friction surfaces during extension and contraction cannot be efficiently transferred to the surrounding environment, the disc spring assemblies will have a high operating temperature. This high operating temperature is detrimental to maintaining the stiffness and coefficient of friction of the disc spring assemblies, and may even cause the disc springs to jam. The solution provides a technical approach by setting an annular cavity in the side wall of the second column section. This annular cavity is used to hold a heat-conducting agent, such as heat-conducting oil, to provide better heat dissipation conditions for the heat generated by the disc spring assemblies and ensure the thermal stability of the disc spring assemblies.

[0033] Meanwhile, this solution can utilize the heat capacity of the heat transfer oil to buffer the local high temperature of the disc spring assembly caused by transient peak heating.

[0034] Meanwhile, this solution can utilize the high-efficiency heat absorption capacity of heat transfer oil to reduce the temperature difference at various locations of the disc spring assembly, thus avoiding localized high temperatures. Attached Figure Description

[0035] Figure 1 This is a cross-sectional view of a specific embodiment of a drill bit assembly with extended lifespan described in this solution; Figure 2 for Figure 1 A magnified view of part A shown; Figure 3 This is a cross-sectional view illustrating the floating ring structure in a specific embodiment of a drill bit assembly with extended lifespan described in this solution.

[0036] The reference numerals in the attached drawings are as follows: 1, first column segment; 2, slot; 3, second column segment; 4, locking bolt; 5, central tube; 6, floating ring; 61, fabric layer; 62, rubber layer; 7, through hole; 8, annular cavity; 9, disc spring assembly; 10, outer side wall; 11, third column segment; 12, inner side wall; 13, plug; 14, spline shaft segment. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments: Example 1

[0038] like Figures 1 to 3 As shown, a drill bit assembly with extended lifespan includes a shock absorber connected in series with the drill bit assembly. The shock absorber includes a first column segment 1 and a second column segment 3. The lower end of the first column segment 1 is embedded in the upper end of the second column segment 3. The first column segment 1 has a spline shaft segment 14 that key-mates with the second column segment 3. It also includes a disc spring assembly 9 disposed in the central hole of the second column segment 3. The disc spring assembly 9 is configured such that the lower end of the first column segment 1 is directly opposite the upper end of the disc spring assembly 9. The first column segment 1 provides axial force to the second column segment 3 through the disc spring assembly 9. An annular cavity 8 is provided on the side wall of the second column segment 3. The annular cavity 8 is coaxial with the disc spring assembly 9. The disc spring assembly 9 is partially or entirely located within the area enclosed by the annular cavity 8 on the second column segment 3.

[0039] This solution is connected in series on the drill string of the drilling assembly during use. The specific connection position on the drill string depends on the structure of the drill string and the object to be protected. For example, it can be set above the drill collar or above the downhole measuring tools. In the specific structure, the disc spring group 9 serves as the elastic element of the shock absorber. The disc spring group 9 is a stacked structure composed of multiple disc springs. The first column segment 1 and the second column segment 3 are in sliding engagement. The first column segment 1 provides torque to the second column segment 3 through the spline shaft segment 14, and the second column segment 3 provides support to the first column segment 1 through the disc spring group 9. When axial vibration occurs on the drill string, the disc spring group 9 expands and contracts to absorb the impact energy, and the first column segment 1 and the second column segment 3 slide relative to each other, thereby isolating the impact and vibration from the bottom of the well from propagating upward and reducing the magnitude of the instantaneous impact on the drill string.

[0040] This solution addresses the use of disc spring assembly 9 as the elastic element of a shock absorber. Disc spring assembly 9 is an elastic element with a high equivalent damping ratio. During its extension and contraction, while the corresponding friction surface efficiently consumes energy, if the heat generated cannot be efficiently transferred to the surrounding environment (such as drilling fluid), it will cause disc spring assembly 9 to have a high operating temperature. This operating temperature is detrimental to maintaining the stiffness and friction coefficient of disc spring assembly 9, and may even cause the disc spring on disc spring assembly 9 to jam. The solution provides a technical solution by setting an annular cavity 8 in the side wall of the second column section 3. The annular cavity 8 is used to hold a heat-conducting agent, which is heat-conducting oil, to provide better heat dissipation conditions for the heat generated by disc spring assembly 9 and ensure the thermal stability of disc spring assembly 9.

[0041] Specifically, the existing disc spring set 9 is generally installed in the outer cylinder (second column segment 3) with solid side wall, and the heat generated by the disc spring set 9 is mainly transmitted outward by the heat conduction of the side wall. Although the metal heat conductivity of the side wall of the second column segment 3 is usually much higher than that of the heat conducting oil, the actual working condition of the shock absorber is that it rotates with the drill pipe, and under the action of stick-slip effect caused by the change of geological resistance and the fluctuation of drill pipe power, the shock absorber has speed fluctuation in the whole drilling process. When the speed of the shock absorber changes, the heat conducting oil in the annular cavity 8 lags behind the movement of the second column segment 3 due to inertia, that is, the heat conducting oil in the annular cavity 8 will have strong shear flow and form transient turbulent flow, which forces the mixing of the cold and hot oil layers on the inside and outside of the annular cavity 8 (under the action of centrifugal force, the high-density cold oil is gathered on the outside of the annular cavity 8, and the low-density hot oil is gathered on the inside of the annular cavity 8). That is, the heat conducting oil in the annular cavity 8 is repeatedly stirred during the rotation of the shock absorber with the drill pipe, avoiding the locking of the hot oil on the inside of the annular cavity 8, so that the oil temperature of the heat conducting oil at different positions in the annular cavity 8 has the characteristics of relative uniformity. As for the transmission of heat generated by the disc spring set 9 to the drilling fluid, after the annular cavity 8 is arranged and the heat conducting oil is arranged in the annular cavity 8, under the actual non-uniform speed rotation condition of the shock absorber, when the heat conducting oil moves relative to the inner wall and the outer wall of the annular cavity 8, the heat transfer coefficient occurring at the two interfaces is much higher than that of the solid metal heat conduction, that is, the heat generated by the disc spring set 9 can be efficiently transmitted from the inner wall of the annular cavity 8 to the heat conducting oil, and the heat of the heat conducting oil can be efficiently transmitted to the outer wall of the annular cavity 8. At the same time, the turbulent mixing of the heat conducting oil itself makes the temperature of the heat conducting oil at different positions in the annular cavity 8 have the characteristics of relative uniformity. In this way, for the transmission of heat generated by the disc spring set 9, the heat conducting oil acts as a heat carrier, and the flow of the heat conducting oil in the annular cavity 8 can efficiently transmit heat from the inner wall of the annular cavity 8 to the outer wall of the annular cavity 8 in the form of convective heat transfer, that is, the lower heat conductivity of the heat conducting oil relative to the metal does not affect the transmission of heat from the inner wall of the annular cavity 8 to the outer wall of the annular cavity 8, solving the problems of radial temperature gradient and inner wall heat accumulation existing in the traditional solid side wall. Compared with the traditional outer cylinder with solid side wall outside the disc spring set 9, the present scheme forms a heat conducting oil cavity surrounding the disc spring set 9 through the annular cavity 8, even if the second column segment 3 with the annular cavity 8 is designed to be thicker (the sum of the thicknesses of the inner and outer metal side walls of the annular cavity 8 is 140% of the thickness of the solid side wall, and the thickness of the inner metal side wall of the annular cavity 8 is less than that of the outer metal side wall), under the similar drilling condition, the working temperature of the disc spring set 9 can be reduced from the highest 140℃ to the highest 110℃.

[0042] As a person skilled in the art, the above coaxial arrangement aims to configure the center of gravity of the second column segment 3 so that the center of gravity of the second column segment 3 is located on its axis as much as possible, and the above thickening of the second column segment 3 with the annular cavity 8 is: relative to the thickening of the case where the side wall of the second column segment 3 is arranged as a solid side wall, the purpose is to guarantee the mechanical properties of the second column segment 3 arranged as a double-layer structure thick, and at the same time, the metal side wall outside the annular cavity 8 (such as the outer side wall 10) is thicker than the metal side wall inside the annular cavity 8 (such as the inner side wall 12), which aims to provide a technical solution with stronger strength reserve for the outer side wall 10 which needs to bear contact load from the outside during work. At the same time, as a person skilled in the art, when the second column segment 3 is thickened, the total thermal resistance of the metal wall will increase to a certain extent during the process of heat transfer from the inside of the second column segment 3 to the outside, and the main reason for the present solution to reduce the working temperature of the disc spring set 9 is: during the stretching and contraction of the disc spring set 9, according to the specific friction position, local hot spots will be formed in the area of the disc spring set 9 of the shock absorber, that is, the temperature distribution at each position of the inner wall of the inner side wall 12 is uneven, and the role of the heat conducting oil is to efficiently transfer heat to each position of the inner wall of the outer side wall 10 by flowing in the annular cavity 8, so that the temperature distribution at each position of the outer wall of the inner side wall 12 and the inner and outer walls of the outer side wall 10 is more uniform, that is, the heat conducting oil forms an efficient heat conduction channel between the inner and outer walls of the annular cavity 8 in the form of a heat carrier, improves the utilization rate of the heat dissipation area of the outer wall of the second column segment 3 in the form of improving the utilization rate of temperature difference, and achieves the purpose of improving the heat transfer capacity of the heat generated by the disc spring set 9 as a whole.

[0043] On the other hand, from the perspective of heat storage, when the present solution uses heat conducting oil with specific heat capacity greater than that of the metal side wall, the heat capacity of the heat conducting oil can be used to buffer the local high temperature of the disc spring set 9 caused by transient peak heat generation.

[0044] On the other hand, from the perspective of heat dissipation, the heat generated by the disc spring set 9 is transferred from the inner side wall 12 to the heat conducting oil, and since the inner side wall 12 can be arranged to be thinner than the outer side wall 10, and the heat conducting oil can efficiently absorb the heat on the inner side wall 12 by flowing relative to the inner side wall 12, the heat conducting oil can be used to reduce the temperature difference at each position of the disc spring set 9 by efficiently absorbing heat, thereby avoiding local high temperature.

[0045] In the present embodiment, although the heat generated by the friction between the heat conducting oil in the annular cavity 8 and the annular cavity 8 is less than 5% of the heat generated by the friction of the disc spring set 9, in order to reduce this part of the heat, the preferred use is to use low-viscosity heat conducting oil, such as nano heat conducting oil, and at the same time, the annular cavity 8 has a smooth inner wall shape.

[0046] To strengthen the role of the heat conducting oil, in the axial direction of the shock absorber, the upper end of the disc spring set 9 is below the upper end of the annular cavity 8, and the lower end of the disc spring set 9 is above or flush with the lower end of the annular cavity 8 on the second shaft section 3, that is, the disc spring set 9 is entirely within the wrapping area of the annular cavity 8 on the second shaft section 3, or the disc spring set 9 is partially within the wrapping area of the annular cavity 8 on the second shaft section 3, that is, in the axial direction of the shock absorber, the disc spring set 9 and the annular cavity 8 have staggered sections, for example, only above or below the disc spring set 9, the annular cavity 8 extends out of the disc spring set 9. As a person skilled in the art, the following example 6 provides a technical solution in which the annular cavity 8 is surrounded by the annular groove on the second shaft section 3 and the annular groove on the third shaft section 11, and in this application, the disc spring set 9 should also be considered to be entirely within the wrapping area of the annular cavity 8 on the second shaft section 3.

[0047] Example 2

[0048] This embodiment is further refined based on example 1: Further comprising a floating ring 6 arranged in the annular cavity 8, the floating ring 6 is a hollow annular structure, and the axis of the floating ring 6 is coaxial with the axis of the annular cavity 8. Further comprising a through hole 7 arranged on the second shaft section 3, one end of the through hole 7 has an orifice on the outer wall of the second shaft section 3, and the other end of the through hole 7 has an orifice intersecting with the upper end of the annular cavity 8, and further comprising a plug 13 for plugging the through hole 7, when the plug 13 is installed in the through hole 7, the annular cavity 8 is closed as a closed cavity.

[0049] The above scheme aims to solve the following problem: for the shock absorber, it is not suitable to set an oil passage for realizing the circulation of the heat-conducting oil in the annular cavity 8, so in specific application, the preferred mode is to set the annular cavity 8 as a closed cavity, that is, to form a closed oil cavity containing the heat-conducting oil. In this application, if the heat-conducting oil fills the annular cavity 8, the pressure increase in the annular cavity 8 caused by the temperature rise of the heat-conducting oil can cause the annular cavity 8 to rupture or even explode. When the heat-conducting oil does not fill the annular cavity 8 so that there is an air gap in the annular cavity 8, the pressure change in the annular cavity 8 caused by the temperature change of the heat-conducting oil is reduced by using the compressed air gap, and when the shock absorber vibrates, the redistribution (shaking) of the heat-conducting oil in the annular cavity 8 will cause the position of the center of gravity of the second column segment 3 to change in the radial direction, which is not conducive to the vibration control of the drill string. Based on the above, a technical scheme is provided for controlling the pressure change in the annular cavity 8 based on the floating ring 6 and avoiding or reducing the redistribution of the heat-conducting oil in the annular cavity 8. Specifically, the floating ring 6 occupying part of the space of the annular cavity 8, when the annular cavity 8 is filled with heat-conducting oil through the through hole 7, when the heat-conducting oil expands or shrinks due to temperature change, the floating ring 6 balances the internal pressure in the annular cavity 8 by synchronously compressing or expanding, and since the floating ring 6 is used to balance the internal pressure in the annular cavity 8, it is not necessary to reserve an air gap at the upper end of the annular cavity 8 to accommodate the expansion or shrinkage of the heat-conducting oil. During the vibration of the shock absorber, the redistribution of the heat-conducting oil in the annular cavity 8 can be effectively avoided, thereby achieving the purpose of facilitating the vibration control of the drill string. The through hole 7 serves as both the heat-conducting oil injection hole and the exhaust hole of the annular cavity 8, and after the oil injection is completed, the through hole 7 is closed by the plug 13, so that the annular cavity 8 is closed as a closed cavity.

[0050] Embodiment 3

[0051] This embodiment is further refined on the basis of Embodiment 2: The floating ring 6 is any one of the following structures: The side wall of the floating ring 6 comprises an outer layer of fabric layer 61 and an inner layer of rubber layer 62; the inner side of the outer layer is attached to the outer side of the inner layer; The side wall of the floating ring 6 is a composite structure with rubber impregnated in the fabric gap; The number of through holes 7 is 2, and each through hole 7 is provided with a plug 13.

[0052] In the above scheme, the side wall of the floating ring 6 formed by the fabric layer 61 and the rubber layer 62 is elastically deformed to adapt to the expansion or compression of the floating ring 6 when the pressure in the annular cavity 8 changes. The rubber layer 62 is used to form a closed hollow cavity inside the floating ring 6 to adapt to the expansion or compression of the floating ring 6. The fabric layer 61 serves as a wear-resistant protective layer outside the rubber layer 62 to ensure the effective service life of the floating ring 6 under the friction with the wall of the annular cavity 8. In the implementation mode of the side wall of the floating ring 6 being a composite structure with rubber impregnated in the fabric gap, the rubber is used to form the hollow cavity inside the floating ring 6, and the fabric is used to ensure the wear resistance of the side wall of the floating ring 6. The number of the through holes 7 is set to realize that one of the through holes 7 is used as an oil injection hole and the other is used as an exhaust hole, thereby improving the oil injection efficiency of the annular cavity 8 and reducing the control difficulty of the air gap formed in the annular cavity 8.

[0053] Embodiment 4

[0054] This embodiment is further refined on the basis of Embodiment 2: The number of the floating rings 6 is multiple.

[0055] Regarding the setting of the number of the floating rings 6, it is intended to realize that for the same volume of the hollow cavity, by setting the number of the floating rings 6 to be multiple, the cross-sectional size of the single floating ring 6 can be smaller, and the local deformation resistance of each floating ring 6 is stronger, so as to reduce the influence of the local deformation of the floating ring 6 on the distribution of the heat conducting oil.

[0056] Embodiment 5

[0057] This embodiment is further refined on the basis of Embodiment 1: The outer wall of the first column segment 1 is provided with a clamping groove 2 extending along the length direction of the first column segment 1, and further comprises a locking bolt 4 threadedly connected to the second column segment 3, and the locking bolt 4 is partially embedded in the clamping groove 2.

[0058] The above scheme is that: in the drilling process, the first column segment 1 needs to provide pressure for the second column segment 3 through the disc spring set 9 to maintain the drilling pressure of the drill bit, and when the drill pipe is lifted or lowered, the clamping groove 2 and the locking bolt 4 are used to prevent the second column segment 3 from sliding off the first column segment 1. Specifically, when the second column segment 3 falls relative to the first column segment 1 to the lower end groove wall of the clamping groove 2 where the locking bolt 4 is supported, the second column segment 3 is hung on the groove wall through the locking bolt 4. The clamping groove 2 in the strip structure is used to realize that the locking bolt 4 does not prevent the relative sliding of the first column segment 1 and the second column segment 3 during the stretching and deformation of the disc spring set 9.

[0059] Embodiment 6

[0060] This embodiment is further refined on the basis of Embodiment 1: A third column segment 11 is also screwed to the lower end of the second column segment 3, and both the second column segment 3 and the third column segment 11 are provided with annular cavities 8, which are in abutment with each other; The lower end of the disc spring set 9 is supported on the end face of the third column segment 11.

[0061] The above scheme is that the upper end of the third column segment 11 is screwed to the lower end of the second column segment 3, so as to provide a bottom support for the disc spring set 9 through the upper end face of the third column segment 11, and further expand the volume of the annular cavity 8 by using the third column segment 11, so as to transfer heat in the annular cavity 8 to a larger heat dissipation structure outside the annular cavity 8, so as to increase the heat dissipation area and promote the reduction of the working temperature of the disc spring set 9.

[0062] Embodiment 7

[0063] This embodiment is further refined on the basis of Embodiment 6: The upper end of the third column segment 11 is provided with a central tube 5, which is embedded in the central hole of the second column segment 3, and the disc spring set 9 is sleeved outside the central tube 5; The side wall of the second column segment 3 includes an outer side wall 10 and an inner side wall 12, both of which are cylindrical structures, the annular cavity 8 is formed between the outer side wall 10 and the inner side wall 12, the upper end of the third column segment 11 is screwed to the outer side of the lower end of the outer side wall 10, the lower end of the inner side wall 12 abuts against the end face of the third column segment 11, and a sealing ring is arranged between the lower end of the inner side wall 12 and the end face of the third column segment 11.

[0064] In the above scheme, the central tube 5 serves as a structure for restricting the central hole of the disc spring set 9, which is aimed at facilitating the form retention of the disc spring set 9 and strengthening the role of the disc spring set 9 in consuming energy through friction. The structure of the second column segment 3 and the matching relationship with the third column segment 11 are as follows: the space on the second column segment 3 for forming the annular cavity 8 is an annular groove surrounding the central hole of the second column segment 3, which is formed between the outer side wall 10 and the inner side wall 12. When the second column segment 3 is connected with the third column segment 11, the annular groove on the second column segment 3 is in abutment with the annular groove on the third column segment 11, forming a complete annular cavity 8. The sealing ring is used to prevent radial leakage at the position where the inner side wall 12 and the end face of the third column segment 11 are in abutment, so that the heat conducting oil can be stably enclosed in the annular cavity 8. This scheme is a technical scheme with simple structure, convenient processing and manufacturing, and assembly.

[0065] Embodiment 8

[0066] This embodiment is further refined on the basis of Embodiment 7: The outer side wall 10 is welded to the second column segment 3 or the inner side wall 12 is welded to the second column segment 3; and the center tube 5 is welded to the third column segment 11.

[0067] The above scheme is that the main body structure of the second column segment 3 and the third column segment 11 can be integrally formed, and the complete part manufacturing is completed by welding on the basis of the corresponding main body structure. In specific application, if the outer side wall 10 is welded to the second column segment 3, in order to guarantee the service life of the second column segment 3, post-weld heat treatment is performed on the corresponding girth weld, a reinforcing ring is used to locally reinforce the girth weld area, and post-weld heat treatment is then performed on the corresponding welding position.

[0068] Embodiment 9

[0069] This embodiment is further refined on the basis of Embodiment 7: The upper end of the center tube 5 is inserted into the center hole of the first column segment 1.

[0070] In the above scheme, the cooperation between the center tube 5 and the first column segment 1 is used to strengthen the coaxial degree maintaining ability of the first column segment 1 and the third column segment 11, so as to increase the contact area by the contact between the second column segment 3 and the first column segment 1 at the position of the spline shaft segment 14 and the contact between the third column segment 11 and the first column segment 1 at the upper end position of the center tube 5, and solve the wear speed at the local position (the position of the spline shaft segment 14 and the upper end position of the center tube 5) in the relative sliding process of the first column segment 1 and the second column segment 3 / third column segment 11.

[0071] Embodiment 10: This embodiment is further refined on the basis of Embodiment 1, and as a specific application, the drill bit assembly includes a drill rod and a drill bit, and the shock absorber is connected in series between the drill rod and the drill bit through the first column segment 1 and the second column segment 3.

[0072] The above is a further detailed description of the present application in combination with specific preferred embodiments, and cannot be regarded as limitation of the specific embodiments of the present application. Other embodiments obtained by those skilled in the art without departing from the technical scheme of the present application should be included in the protection scope of the present application.

Claims

1. A drill bit assembly with extended service life, comprising a shock absorber connected in series on the drill bit assembly, the shock absorber comprising a first column segment (1) and a second column segment (3), the lower end of the first column segment (1) being embedded in the upper end of the second column segment (3), the first column segment (1) having a spline shaft segment (14) keyed to the second column segment (3); further comprising a disc spring assembly (9) disposed in a central hole of the second column segment (3), the disc spring assembly (9) being configured such that the lower end of the first column segment (1) is directly opposite the upper end of the disc spring assembly (9), the first column segment (1) providing axial force to the second column segment (3) through the disc spring assembly (9), characterized in that, An annular cavity (8) is provided on the side wall of the second column segment (3). The annular cavity (8) is coaxial with the disc spring assembly (9). The disc spring assembly (9) is partially or entirely located within the area enclosed by the annular cavity (8) on the second column segment (3).

2. The drill bit assembly with extended service life according to claim 1, characterized in that, It also includes a floating ring (6) disposed in the annular cavity (8), the floating ring (6) being a hollow annular structure, and the axis of the floating ring (6) being coaxial with the axis of the annular cavity (8); It also includes a through hole (7) provided on the second column section (3). One end of the through hole (7) is located on the outer wall of the second column section (3), and the other end of the through hole (7) intersects with the upper end of the annular cavity (8). It also includes a plug (13) for sealing the through hole (7). When the plug (13) is installed in the through hole (7), the annular cavity (8) is sealed into a closed cavity.

3. The drill bit assembly with extended service life according to claim 2, characterized in that, The floating ring (6) can be any of the following structures: The sidewall of the float ring (6) includes an outer layer of fabric (61) and an inner layer of rubber (62); the inner side of the outer layer is attached to the outer side of the inner layer. The sidewall of the floating ring (6) is a composite structure in which rubber is impregnated in the fabric gaps; The number of the through holes (7) is 2, and each through hole (7) is equipped with a plug (13).

4. A drill bit assembly with extended service life according to claim 2 or 3, characterized in that, The number of the floating rings (6) is multiple.

5. A drill bit assembly with extended service life according to claim 1, characterized in that, The outer wall of the first column segment (1) is provided with a slot (2) extending along the length direction of the first column segment (1), and also includes a locking bolt (4) threadedly connected to the second column segment (3), wherein the locking bolt (4) is partially embedded in the slot (2).

6. The drill bit assembly with extended service life according to claim 1, characterized in that, It also includes a third column section (11) that is threaded to the lower end of the second column section (3). Both the second column section (3) and the third column section (11) are provided with annular cavities (8), and the annular cavities (8) of the two are connected to each other. The lower end of the disc spring assembly (9) is supported on the end face of the third column segment (11).

7. A drill bit assembly with extended service life according to claim 6, characterized in that, The upper end of the third column section (11) is provided with a central tube (5), which is embedded in the central hole of the second column section (3), and the disc spring assembly (9) is sleeved on the outside of the central tube (5). The sidewall of the second column segment (3) includes an outer sidewall (10) and an inner sidewall (12), both of which are cylindrical structures. The annular cavity (8) is formed between the outer sidewall (10) and the inner sidewall (12). The upper end of the third column segment (11) is threaded to the lower end of the outer sidewall (10). The lower end of the inner sidewall (12) abuts against the end face of the third column segment (11). A sealing ring is provided between the lower end of the inner sidewall (12) and the end face of the third column segment (11).

8. A drill bit assembly with extended service life according to claim 7, characterized in that, The outer side wall (10) is welded to the second column segment (3) or the inner side wall (12) is welded to the second column segment (3); the central tube (5) is welded to the third column segment (11).

9. A drill bit assembly with extended service life according to claim 7 or 8, characterized in that, The upper end of the central tube (5) is inserted into the central hole of the first column segment (1).

10. A drill bit assembly with extended service life according to claim 1, characterized in that, It also includes drill rod and drill bit, and the shock absorber is connected in series between drill rod and drill bit through a first column section (1) and a second column section (3).

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