Metal sealing element for oil-gas drilling machine and processing technology of metal sealing element

Abstract

The invention discloses a metal sealing element for an oil-gas drilling rig and a machining process thereof, and particularly relates to the technical field of oil-gas drilling rig sealing. The metal sealing element comprises a shell, a movable ring, a static ring and an adjusting assembly, and the movable ring and the static ring are arranged in the shell; the adjusting assembly is arranged at the end, away from the movable ring, of the static ring, when the movable ring is static, the adjusting assembly can extrude the static ring to enable the static ring to be tightly attached to the end face of the movable ring, and the adjusting assembly can balance pressure borne by the static ring; a first guide groove and a second guide groove are formed in the end face of the movable ring, when the movable ring rotates at a low speed, the second guide groove can extrude an internal medium to form a liquid film, and when the movable ring rotates at a high speed, the first guide groove can compress external gas to form a gas film. And a gaseous boundary is formed on the outer layer of the liquid film, so that the problem that a medium in the liquid film leaks due to the action of centrifugal force when the moving ring rotates at a high speed is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas drilling rig sealing, and more particularly to a metal sealing component for oil and gas drilling rig and a processing technology thereof. Background Art

[0002] During drilling operations, the drill pipe rotates at a speed of tens to hundreds of revolutions per minute, while being subjected to the combined effects of high temperature, high pressure, abrasive mud, and corrosive media such as hydrogen sulfide downhole. During the drilling process, drilling fluid is usually introduced into the drill pipe to cool the drill bit and discharge the mud inside the drilling well. However, due to the rotation of the drill pipe, the fluid inlet of the drill pipe is prone to leakage. Traditional sealing technology mostly adopts a combination of mechanical seals and elastomeric sealing rings to achieve dynamic sealing through contact sealing surface compression. However, contact sealing is prone to wear between the sealing surfaces, and under high-speed rotation, the seals are very likely to generate high temperatures and cause leakage.

[0003] Chinese patent application number 202323406982.8 discloses a mechanical seal structure including two sets of sealing rings, a compensation ring seat and a rotating ring seat. The sealing ring includes a compensation ring and a rotating ring. The rotating ring seat is connected to the rotating shaft of the stirring tank equipment. The rotating ring is connected to the rotating ring seat. When the rotating shaft of the stirring tank equipment rotates, the rotating ring and the rotating ring seat will also rotate accordingly. The cross-section of the compensation ring is stepped. The width of the first end of the compensation ring gradually increases toward the width of the second end of the compensation ring. The compensation ring seat is connected to the first end of the compensation ring. The second end of the compensation ring is connected to the other end of the rotating ring. When the rotating ring rotates, the compensation ring and the compensation base remain stationary. The cross-sectional shapes of the compensation ring and the rotating ring have undergone special finite element structural calculations. When the sealing structure is in operation, it is more conducive to the lubricating liquid to enter the end face where the rotating ring and the compensation ring are in contact, forming an effective and complete liquid film, thereby improving the service life of the rotating ring and the compensation ring. However, this patent uses a spring to provide pressure to make the sealing surface fit tightly. During the attempt to use it, the spring will fatigue, causing the sealing surface to not fit tightly. The uneven pressure causes uneven wear of the sealing surface between the dynamic ring and the static ring, and a stable liquid film cannot be formed.

[0004] Moreover, when the drilling fluid inside the oil and gas drilling rig forms a liquid film, due to the high-speed rotation of the drilling rig, the medium inside the liquid film may leak due to the action of centrifugal force. Therefore, the present invention proposes a metal seal for oil and gas drilling rigs and its processing technology to solve the above problem. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a metal seal for oil and gas drilling rigs and a processing technology thereof to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: A metal seal for oil and gas drilling rigs, comprising: a shell, a dynamic ring, a static ring and an adjustment assembly, wherein the dynamic ring and the static ring are arranged inside the shell; the adjustment assembly is arranged at the end of the static ring away from the dynamic ring, and when the dynamic ring is stationary, the adjustment assembly can squeeze the static ring so that the static ring and the end face of the dynamic ring fit tightly, and the adjustment assembly can balance the pressure on the static ring; the end face of the dynamic ring is respectively provided with a first guide groove and a second guide groove, and when the dynamic ring rotates at a low speed, the second guide groove can squeeze the internal medium to form a liquid film, and when the dynamic ring rotates at a high speed, the first guide groove can compress the external gas to form an air film.

[0007] Preferably, the first guide groove and the second guide groove are both multiple and distributed in a circumferential array on the end surface of the moving ring close to the stationary ring. The opening of the first guide groove is set on the outer wall of the moving ring, and the opening of the second guide groove is set on the inner wall of the moving ring.

[0008] Preferably, the adjustment assembly includes a stationary ring seat arranged inside the shell, a sliding groove is opened inside the stationary ring seat, a piston plate is slidably connected inside the sliding groove, one end of the piston plate is fixedly connected to a piston rod, and the end of the piston rod away from the piston plate is fixedly connected to the stationary ring.

[0009] Preferably, the slide grooves are multiple and distributed in a circumferential array, and an air groove is opened inside the static ring seat, and the air groove is connected to the multiple slide grooves through a pipeline.

[0010] Preferably, the width of the first guide groove gradually decreases from the outer wall of the movable ring to the inner wall of the movable ring, and the width of the second guide groove gradually decreases from the inner wall of the movable ring to the outer wall of the movable ring.

[0011] Preferably, the dynamic ring is rotatably connected to one end of the shell, the static ring seat is fixedly connected to the end of the shell away from the dynamic ring, the interior of the shell is filled with inert gas, and the side wall of the shell is provided with air holes for replenishing inert gas.

[0012] Preferably, compressed gas is provided inside the gas tank, and a through hole for adjusting the gas pressure inside the gas tank is opened on the outer wall of the gas tank.

[0013] Preferably, the interiors of the dynamic ring and the static ring are both provided with sealing rings to prevent leakage of the internal medium, and the two sealing rings are respectively provided at both ends of the contact surface between the dynamic ring and the static ring.

[0014] Preferably, an outer wall of the shell is provided with an avoidance hole corresponding to the through hole of the air groove.

[0015] The present invention also provides a process for processing a metal seal for an oil and gas drilling rig, comprising the following steps: S1. Processing the dynamic ring and the static ring: Use the machining center to process the blank and produce the dynamic ring and the static ring with the corresponding parameters; S2 processing the first guide groove and the second guide groove; S3. Processing the stationary ring seat, using CNC machine tools to process the blank, produce the corresponding parameters of the stationary ring seat, and use a drilling machine to process the through hole on the outer wall of the gas groove; S4. Process the shell by using a CNC machine tool to process the blank to produce a shell with corresponding parameters, and use a drilling machine to process the air holes and avoidance holes on the outer wall of the shell.

[0016] Technical effects and advantages of the present invention: 1. The present invention connects multiple chutes with the gas groove, so that the multiple chutes are subjected to the same pressure of compressed gas, and thus the multiple piston rods provide the same pressure to the static ring, preventing the problem of liquid film failure and instability caused by uneven pressure on the static ring.

[0017] 2. The present invention provides pressure to the static ring by squeezing the piston plate with compressed gas, replacing the spring, thereby preventing the problem of loose sealing surface due to spring fatigue.

[0018] 3. The present invention squeezes the inert gas through the first guide groove so that when the moving ring rotates at high speed, the outer layer of the liquid film forms a gaseous boundary, thereby preventing the medium inside the liquid film from leaking due to the action of centrifugal force when the moving ring rotates at high speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 It is a cross-sectional view of the overall structure of the present invention.

[0021] Figure 3 This is a cross-sectional view of the stationary ring and adjustment assembly of the present invention.

[0022] Figure 4 Schematic diagram of the first guide groove and the second guide groove of the present invention.

[0023] The figures are marked as follows: 1. housing; 2. dynamic ring; 21. first guide groove; 22. second guide groove; 3. stationary ring; 4. adjustment assembly; 41. stationary ring seat; 42. slide groove; 421. piston plate; 422. piston rod; 43. air groove. DETAILED DESCRIPTION

[0024] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Example 1 In actual production, due to long-term use of springs, fatigue occurs, resulting in loose sealing surfaces, uneven pressure, and uneven wear of the sealing surfaces between the dynamic ring and the static ring, making it impossible to stably form a liquid film. This embodiment is specially invented to solve the above problems.

[0026] See also Figures 1 to 4 As shown, a metal seal for oil and gas drilling rigs in this embodiment includes a shell 1, a dynamic ring 2, a static ring 3 and an adjustment assembly 4, wherein the dynamic ring 2 and the static ring 3 are arranged inside the shell 1; the adjustment assembly 4 is arranged at the end of the static ring 3 away from the dynamic ring 2, and when the dynamic ring 2 is stationary, the adjustment assembly 4 can squeeze the static ring 3 so that the static ring 3 and the end face of the dynamic ring 2 are tightly fitted, and the adjustment assembly 4 can balance the pressure on the static ring 3; the end face of the dynamic ring 2 is respectively provided with a first guide groove 21 and a second guide groove 22, when the dynamic ring 2 rotates at a low speed, the second guide groove 22 can squeeze the internal medium to form a liquid film, and when the dynamic ring 2 rotates at a high speed, the first guide groove 21 can compress the external gas to form an air film, wherein, when the dynamic ring 2 rotates, the gas and drilling fluid are brought into the sealing surface gap due to the viscosity, forming a shear flow, and the gas and drilling fluid are compressed in the groove to generate dynamic pressure, thereby expanding the sealing surface to form a stable liquid film and air film.

[0027] See also Figure 4 As shown, both the first guide groove 21 and the second guide groove 22 are multiple and circumferentially arrayed on the end face of the moving ring 2 close to the stationary ring 3. The opening of the first guide groove 21 is set on the outer wall of the moving ring 2, and the opening of the second guide groove 22 is set on the inner wall of the moving ring 2. The first guide groove 21 and the second guide groove 22 are both spiral grooves, and the spiral directions of the first guide groove 21 and the second guide groove 22 are the same. The second guide groove 22 has a larger groove depth and a smaller inclination angle, and is used to form a stable liquid film by increasing the pumping capacity. For example, the second guide groove 22 has a groove depth of 15-20μm and an inclination angle of 15°-20°, while the first guide groove 21 has a smaller groove depth and a larger inclination angle, which enhances the tangential shear flow and improves the dynamic pressure generation efficiency, and is used to form an air film. For example, the first guide groove 21 has a groove depth of 5-8μm and an inclination angle of 25°-30°.

[0028] See also Figure 2 and Figure 3As shown, the adjustment assembly 4 includes a stationary ring seat 41 arranged inside the shell 1, a slide groove 42 is opened inside the stationary ring seat 41, a piston plate 421 is slidably connected inside the slide groove 42, one end of the piston plate 421 is fixedly connected to the piston rod 422, and the end of the piston rod 422 away from the piston plate 421 is fixedly connected to the stationary ring 3.

[0029] See also Figure 3 As shown, there are multiple slide grooves 42 distributed in a circumferential array, and an air groove 43 is opened inside the static ring seat 41. The air groove 43 is connected to the multiple slide grooves 42 through a pipeline.

[0030] See also Figure 4 As shown, the width of the first guide groove 21 gradually decreases from the outer wall of the movable ring 2 to the inner wall of the movable ring 2 , and the width of the second guide groove 22 gradually decreases from the inner wall of the movable ring 2 to the outer wall of the movable ring 2 .

[0031] See also Figure 2 As shown, the dynamic ring 2 is rotatably connected to one end of the shell 1, and the static ring seat 41 is fixedly connected to the end of the shell 1 away from the dynamic ring 2. The interior of the shell 1 is filled with inert gas, and the side wall of the shell 1 is provided with air holes for replenishing the inert gas, wherein the inert gas is nitrogen.

[0032] See also Figure 2 and Figure 3 As shown, compressed gas is provided inside the air tank 43, and a through hole for adjusting the air pressure inside the air tank 43 is provided on the outer wall of the air tank 43, and an avoidance hole corresponding to the through hole of the air tank 43 is provided on the outer wall of the shell 1. Inflating or deflating the air tank 43 through the through hole to adjust the air pressure inside the air tank 43 is an existing technology and will not be elaborated here.

[0033] See also Figure 2 As shown, sealing rings are provided inside the dynamic ring 2 and the static ring 3 to prevent leakage of the internal medium. The two sealing rings are respectively provided at both ends of the contact surface of the dynamic ring 2 and the static ring 3.

[0034] During use, when the dynamic ring 2 and the static ring 3 are relatively stationary, the compressed gas in the gas groove 43 enters the multiple slide grooves 42 through the pipeline to provide pressure to the piston plate 421, so that the piston plate 421 squeezes the static ring 3 through the piston rod 422, so that the end face of the static ring 3 is closely fitted with the end face of the dynamic ring 2. By adjusting the pressure of the compressed gas in the gas groove 43, the static pressure between the sealing surfaces of the static ring 3 and the dynamic ring 2 is adjusted. When the dynamic ring 2 rotates with the drill pipe, the drilling fluid is brought into the second guide groove 22 due to the viscosity. When the dynamic ring 2 rotates, the high viscosity drilling fluid is sheared through the second guide groove 22. The liquid produces a dynamic pressure effect, so that the drilling fluid is squeezed in the groove to generate dynamic pressure. When the drilling fluid pressure inside the second guide groove 22 is greater than the pressure provided by the compressed gas inside the slide groove 42, the static ring 3 moves away from the dynamic ring 2, so that the compressed gas is further squeezed. At the same time, a liquid film is formed between the static ring 3 and the dynamic ring 2, and is connected to the air groove 43 through multiple slide grooves 42, so that the multiple slide grooves 42 are subjected to the same pressure of the compressed gas, so that the multiple piston rods 422 provide the same pressure to the static ring 3, thereby preventing the problem of the liquid film being unable to form and being unstable due to uneven pressure on the static ring 3.

[0035] Example 2 In actual use, it was found that when the dynamic ring rotated at high speed, the drilling fluid viscosity decreased due to the increase in temperature, and the medium inside the liquid film leaked due to the action of centrifugal force. Further improvements were made on the basis of the above embodiment.

[0036] On the basis of the above embodiment, when in use, when the moving ring 2 rotates at a low speed, due to the high viscosity of the drilling fluid, when the moving ring 2 rotates, the high viscosity drilling fluid is sheared through the second guide groove 22 to form a stable liquid film, and the inert gas is compressed through the first guide groove 21 by the rotation of the moving ring 2. Since the formation of the liquid film and the air film is positively correlated with the viscosity coefficient and the rotation speed of the medium, and the viscosity of the inert gas is relatively small, when the moving ring 2 rotates at a low speed, the inert gas cannot form an effective air film. At this time, the inert gas only flows between the moving ring 2 and the static ring 3, which is close to the static ring 3 and the moving ring 2. The cover is cooled. When the dynamic ring 2 rotates at high speed, the inert gas forms an air film between the sealing surfaces of the dynamic ring 2 and the static ring 3 due to the dynamic pressure. Since the first guide groove 21 is on the outer wall of the dynamic ring 2 and the second guide groove 22 is on the inner wall of the dynamic ring 2, the air film is on the outer layer of the liquid film, thereby forming a gaseous boundary on the outer layer of the liquid film. Since the first guide groove 21 compresses the inert gas from the outside of the dynamic ring 2 to the inside of the dynamic ring 2, the air film squeezes the liquid film toward the inside of the dynamic ring 2, thereby preventing the medium inside the liquid film from leaking due to the action of centrifugal force when the dynamic ring 2 rotates at high speed.

[0037] Example 3 Based on the above embodiment, this embodiment further provides a processing technology for a metal seal for oil and gas drilling rigs, including the following specific steps: S1. Processing the dynamic ring 2 and the static ring 3, using a machining center to process the blank to produce the dynamic ring 2 and the static ring 3 with the corresponding parameters; S2 processing the first guide groove 21 and the second guide groove 22; S3 processing stationary ring seat 41, using CNC machine tools to process the blank, produce the corresponding parameters of the stationary ring seat 41, and the use of drilling machine processing gas groove 43 outer wall through hole; S4. Processing the shell 1: Use a CNC machine tool to process the blank to produce a shell 1 with corresponding parameters, and use a drilling machine to process the air holes and avoidance holes on the outer wall of the shell 1.

[0038] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A metal seal for an oil and gas drilling rig, comprising a housing (1), characterized in that: Also includes: A dynamic ring (2) and a static ring (3), wherein the dynamic ring (2) and the static ring (3) are arranged inside the housing (1); An adjusting component (4), wherein the adjusting component (4) is arranged at one end of the stationary ring (3) away from the dynamic ring (2); when the dynamic ring (2) is stationary, the adjusting component (4) can squeeze the stationary ring (3) so that the end faces of the stationary ring (3) and the dynamic ring (2) are closely fitted together, and the adjusting component (4) can balance the pressure on the stationary ring (3); The end surface of the movable ring (2) is respectively provided with a first guide groove (21) and a second guide groove (22). When the movable ring (2) rotates at a low speed, the second guide groove (22) can squeeze the internal medium to form a liquid film. When the movable ring (2) rotates at a high speed, the first guide groove (21) can compress the external gas to form an air film.

2. The metal seal for oil and gas drilling rigs according to claim 1, characterized in that: The first guide groove (21) and the second guide groove (22) are both multiple and distributed in a circumferential array on the end surface of the moving ring (2) close to the stationary ring (3), the opening of the first guide groove (21) is arranged on the outer wall of the moving ring (2), and the opening of the second guide groove (22) is arranged on the inner wall of the moving ring (2).

3. The metal seal for oil and gas drilling rigs according to claim 2, characterized in that: The regulating assembly (4) includes a stationary ring seat (41) arranged inside the housing (1), a slide groove (42) is provided inside the stationary ring seat (41), a piston plate (421) is slidably connected inside the slide groove (42), one end of the piston plate (421) is fixedly connected to a piston rod (422), and the end of the piston rod (422) away from the piston plate (421) is fixedly connected to the stationary ring (3).

4. The metal seal for oil and gas drilling rigs according to claim 3, characterized in that: The slide grooves (42) are multiple and distributed in a circumferential array. An air groove (43) is provided inside the stationary ring seat (41). The air groove (43) is connected to the multiple slide grooves (42) through a pipeline.

5. The metal seal for oil and gas drilling rigs according to claim 4, characterized in that: The width of the first guide groove (21) gradually decreases from the outer wall of the movable ring (2) to the inner wall of the movable ring (2), and the width of the second guide groove (22) gradually decreases from the inner wall of the movable ring (2) to the outer wall of the movable ring (2).

6. The metal seal for oil and gas drilling rigs according to claim 5, characterized in that: The dynamic ring (2) is rotatably connected to one end of the housing (1), and the static ring seat (41) is fixedly connected to one end of the housing (1) away from the dynamic ring (2). The interior of the housing (1) is filled with inert gas, and a side wall of the housing (1) is provided with an air hole for replenishing the inert gas.

7. The metal seal for oil and gas drilling rigs according to claim 6, characterized in that: Compressed gas is provided inside the gas groove (43), and a through hole for adjusting the internal gas pressure of the gas groove (43) is provided on the outer wall of the gas groove (43).

8. The metal seal for oil and gas drilling rigs according to claim 7, characterized in that: The interiors of the dynamic ring (2) and the static ring (3) are both provided with sealing rings for preventing leakage of the internal medium, and the two sealing rings are respectively provided at the two ends of the contact surfaces of the dynamic ring (2) and the static ring (3).

9. The metal seal for oil and gas drilling rigs according to claim 8, characterized in that: The outer wall of the housing (1) is provided with a avoidance hole corresponding to the through hole of the air groove (43).

10. A processing technology for a metal seal for oil and gas drilling rigs, the processing technology being used for processing the metal seal for oil and gas drilling rigs according to claim 9, characterized in that: The following steps are involved: S1. Processing the dynamic ring (2) and the static ring (3): using a machining center to process the blank to produce the dynamic ring (2) and the static ring (3) with corresponding parameters; S2. Processing the first guide groove (21) and the second guide groove (22); S3 processing stationary ring seat (41), using CNC machine tools to process the blank, produce the corresponding parameters of the stationary ring seat (41), and use a drilling machine to process the through hole of the outer wall of the gas groove (43); S4. Processing the shell (1), using a CNC machine tool to process the blank to produce a shell (1) with corresponding parameters, and using a drilling machine to process the air holes and avoidance holes on the outer wall of the shell (1).

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