A metal seal for oil and gas drilling rigs and its processing technology

Abstract

The application discloses a metal sealing element for an oil and gas drilling machine and a processing technology thereof, and particularly relates to the sealing technical field of the oil and gas drilling machine, which comprises a shell, a moving ring, a static ring and an adjusting assembly, the moving ring and the static ring are arranged in the interior of the shell; the adjusting assembly is arranged at the end of the static ring away from the moving ring, when the moving ring is static, the adjusting assembly can make the end surface of the static ring and the moving ring closely adhere by extruding the static ring, and the adjusting assembly can balance the pressure received by the static ring; the end surface of the moving ring is respectively provided with a first guide groove and a second guide groove, when the moving ring rotates at low speed, the second guide groove can extrude the internal medium to form a liquid film, when the moving ring rotates at high speed, the first guide groove can compress the external gas to form a gas film, the inert gas is extruded by 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 leakage of the medium in the liquid film caused by the centrifugal force when the moving ring rotates at high speed.

Description

Technical Field

[0001] This invention relates to the field of sealing technology for oil and gas drilling rigs, and more specifically, to a metal seal for oil and gas drilling rigs and its processing technology. Background Technology

[0002] During drilling operations, the drill pipe rotates at speeds of tens to hundreds of revolutions per minute, simultaneously enduring the combined effects of high temperatures, high pressures, abrasive mud, and corrosive media such as hydrogen sulfide downhole. During drilling, drilling fluid is typically introduced into the drill pipe to cool the drill bit and remove mud from inside the well. However, due to the rotation of the drill pipe, the fluid inlet is prone to leakage. Traditional sealing technologies often employ a combination of mechanical seals and elastomer sealing rings, achieving dynamic sealing through contact sealing surface compression. However, contact sealing is prone to wear between sealing surfaces, and the seals are highly susceptible to high temperatures and leakage under high-speed rotation.

[0003] Chinese Patent Application No. 202323406982.8 discloses a mechanical seal structure including two sets of sealing rings, a compensating ring seat, and a rotating ring seat. The sealing rings include a compensating ring and a rotating ring. The rotating ring seat is connected to the rotating shaft of the mixing vessel, and the rotating ring is connected to the rotating ring seat. When the rotating shaft of the mixing vessel rotates, the rotating ring and the rotating ring seat also rotate. The cross-section of the compensating ring is stepped, with the width of the first end of the compensating ring gradually increasing towards the second end. The compensating ring seat is connected to the first end of the compensating ring, and the second end of the compensating ring is connected to the other end of the rotating ring. When the rotating ring rotates, the compensating ring and the compensating base remain stationary. The cross-sectional shapes of both the compensating ring and the rotating ring have undergone special finite element structural calculations. During operation, the sealing structure facilitates the entry of lubricating fluid into the end face where the rotating ring and the compensating ring are in contact, forming an effective and complete liquid film and improving the service life of the rotating ring and the compensating ring. However, this patent uses a spring to provide pressure to make the sealing surfaces fit tightly. During trial use, the spring may fatigue, causing the sealing surfaces to not fit tightly. Uneven pressure causes uneven wear on the sealing surfaces between the rotating ring and the stationary ring, making it impossible to stably form a liquid film.

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

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

[0006] To achieve the above objectives, the present invention provides the following technical solution: a metal seal for an oil and gas drilling rig, comprising: a housing, a rotating ring, a stationary ring, and an adjusting assembly, wherein the rotating ring and the stationary ring are disposed inside the housing; the adjusting assembly is disposed at the end of the stationary ring away from the rotating ring, and when the rotating ring is stationary, the adjusting assembly can compress the stationary ring to make the end face of the rotating ring fit tightly against it, and the adjusting assembly can balance the pressure on the stationary ring; the end face of the rotating ring is respectively provided with a first guide groove and a second guide groove, wherein when the rotating ring rotates at low speed, the second guide groove can compress the internal medium to form a liquid film, and when the rotating ring rotates at high speed, the first guide groove can compress the external gas to form a gas film.

[0007] Preferably, there are multiple first guide grooves and second guide grooves, which are circumferentially arrayed on the end face of the moving ring near the stationary ring. The opening of the first guide groove is located on the outer wall of the moving ring, and the opening of the second guide groove is located on the inner wall of the moving ring.

[0008] Preferably, the adjusting assembly includes a stationary ring seat disposed inside the housing, the stationary ring seat having a sliding groove inside, a piston plate being slidably connected inside the sliding groove, a piston rod being fixedly connected to one end of the piston plate, and the end of the piston rod away from the piston plate being fixedly connected to the stationary ring.

[0009] Preferably, there are multiple sliding grooves arranged in a circumferential array, and an air groove is provided inside the stationary ring seat. The air groove is connected to the multiple sliding grooves through a pipe.

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

[0011] Preferably, the moving ring is rotatably connected to one end of the housing, the stationary ring seat is fixedly connected to the end of the housing away from the moving ring, the interior of the housing is filled with inert gas, and the side wall of the housing is provided with vent holes for replenishing inert gas.

[0012] Preferably, the air tank is filled with compressed gas, and the outer wall of the air tank has through holes for adjusting the air pressure inside the air tank.

[0013] Preferably, both the rotating ring and the stationary ring are provided with sealing rings to prevent leakage of the internal medium, and the two sealing rings are respectively located at both ends of the contact surface of the rotating ring and the stationary ring.

[0014] Preferably, the outer wall of the housing is provided with a clearance hole corresponding to the through hole of the air groove.

[0015] This invention also provides a processing technology for metal seals used in oil and gas drilling rigs, comprising the following steps:

[0016] S1. Machining the moving ring and stationary ring: Use a machining center to machine the blank to produce the moving ring and stationary ring with the corresponding parameters;

[0017] S2. Machining the first guide groove and the second guide groove;

[0018] S3. Machining the stationary ring seat: Use a CNC machine tool to machine the blank to produce a stationary ring seat with the corresponding parameters, and use a drilling machine to machine the through hole on the outer wall of the air groove.

[0019] S4. Machining the shell: Use a CNC machine tool to machine the blank to produce a shell with the corresponding parameters, and use a drilling machine to machine the air holes and clearance holes on the outer wall of the shell.

[0020] The technical effects and advantages of this invention are as follows:

[0021] 1. The present invention connects multiple sliding grooves to the gas grooves, thereby ensuring that the multiple sliding grooves are subjected to the same pressure of compressed gas, which in turn ensures that the multiple piston rods provide the same pressure to the stationary ring, preventing uneven pressure on the stationary ring from causing the liquid film to fail to form or become unstable.

[0022] 2. This invention uses compressed gas to pressurize the piston plate, thereby providing pressure to the stationary ring instead of a spring, thus preventing spring fatigue and ensuring a tight seal between the sealing surfaces.

[0023] 3. The present invention uses the first guide groove to compress inert gas, so that when the moving ring rotates at high speed, a gaseous boundary is formed on the outer layer of the liquid film, thereby preventing leakage of the medium inside the liquid film due to centrifugal force when the moving ring rotates at high speed. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0025] Figure 2 This is a cross-sectional view of the overall structure of the present invention.

[0026] Figure 3 This is a cross-sectional view of the stationary ring and adjustment component of the present invention.

[0027] Figure 4 This is a schematic diagram of the first guide groove and the second guide groove of the present invention.

[0028] The attached figures are labeled as follows: 1. Housing; 2. Moving 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 Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] In actual production, long-term use of springs can lead to fatigue, resulting in loose sealing surfaces and uneven pressure. This causes uneven wear on the sealing surfaces between the rotating and stationary rings, making it impossible to stably form a liquid film. This embodiment is invented to solve the above problems.

[0032] Please see Figures 1 to 4 As shown, a metal seal for an oil and gas drilling rig in this embodiment includes a housing 1, a rotating ring 2, a stationary ring 3, and an adjusting component 4. The rotating ring 2 and the stationary ring 3 are disposed inside the housing 1. The adjusting component 4 is disposed at the end of the stationary ring 3 away from the rotating ring 2. When the rotating ring 2 is stationary, the adjusting component 4 can squeeze the stationary ring 3 to make the end face of the stationary ring 3 fit tightly against the end face of the rotating ring 2, and the adjusting component 4 can balance the pressure on the stationary ring 3. The end face of the rotating ring 2 is respectively provided with a first guide groove 21 and a second guide groove 22. When the rotating ring 2 rotates at low speed, the second guide groove 22 can squeeze the internal medium to form a liquid film. When the rotating ring 2 rotates at high speed, the first guide groove 21 can compress the external gas to form a gas film. When the rotating ring 2 rotates, the gas and drilling fluid are carried into the gap of the sealing surface due to viscosity, forming shear flow. The gas and drilling fluid are compressed in the groove to generate dynamic pressure, thereby opening the sealing surface to form a stable liquid film and gas film.

[0033] Please see Figure 4 As shown, there are multiple first guide grooves 21 and second guide grooves 22 arranged in a circumferential array on the end face of the moving ring 2 near the stationary ring 3. The opening of the first guide groove 21 is located on the outer wall of the moving ring 2, and the opening of the second guide groove 22 is located on the inner wall of the moving ring 2. Both the first guide groove 21 and the second guide groove 22 are 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, which increases the pumping capacity and is used to form a stable liquid film. For example, the groove depth of the second guide groove 22 is 15-20 μm and the inclination angle is 15°-20°. 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 a gas film. For example, the groove depth of the first guide groove 21 is 5-8 μm and the inclination angle is 25°-30°.

[0034] Please see Figure 2 and Figure 3As shown, the adjustment assembly 4 includes a stationary ring seat 41 disposed inside the housing 1. A sliding groove 42 is provided inside the stationary ring seat 41. A piston plate 421 is slidably connected inside the sliding groove 42. A piston rod 422 is fixedly connected to one end of the piston plate 421. The end of the piston rod 422 away from the piston plate 421 is fixedly connected to the stationary ring 3.

[0035] Please see Figure 3 As shown, there are multiple sliding grooves 42 arranged 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 sliding grooves 42 through a pipe.

[0036] Please see Figure 4 As shown, the width of the first guide groove 21 gradually decreases from the outer wall of the moving ring 2 to the inner wall of the moving ring 2, and the width of the second guide groove 22 gradually decreases from the inner wall of the moving ring 2 to the outer wall of the moving ring 2.

[0037] Please see Figure 2 As shown, the moving ring 2 is rotatably connected to one end of the housing 1, and the stationary ring seat 41 is fixedly connected to the end of the housing 1 away from the moving ring 2. The interior of the housing 1 is filled with inert gas, and the side wall of the housing 1 is provided with vent holes for replenishing inert gas, wherein the inert gas is nitrogen.

[0038] Please see Figure 2 and Figure 3 As shown, compressed gas is provided inside the air groove 43, and a through hole is provided on the outer wall of the air groove 43 for adjusting the air pressure inside the air groove 43. An avoidance hole corresponding to the through hole of the air groove 43 is provided on the outer wall of the housing 1. The method of adjusting the air pressure inside the air groove 43 by filling or releasing air into the air groove 43 through the through hole is existing technology and will not be described in detail here.

[0039] Please see Figure 2 As shown, both the rotating ring 2 and the stationary ring 3 are equipped with sealing rings to prevent leakage of the internal medium. The two sealing rings are respectively located at both ends of the contact surface of the rotating ring 2 and the stationary ring 3.

[0040] During operation, when the rotating ring 2 and the stationary ring 3 are relatively stationary, the compressed gas inside the gas groove 43 enters multiple sliding grooves 42 through pipes to provide pressure to the piston plate 421. This causes the piston plate 421 to squeeze the stationary ring 3 through the piston rod 422, resulting in a tight fit between the end face of the stationary ring 3 and the end face of the rotating ring 2. By adjusting the pressure of the compressed gas inside the gas groove 43, the static pressure between the sealing surfaces of the stationary ring 3 and the rotating ring 2 is adjusted. When the rotating ring 2 rotates with the drill pipe, the drilling fluid is carried into the second guide groove 22 due to viscosity. As the rotating ring 2 rotates, the high-viscosity drilling fluid is sheared through the second guide groove 22. The fluid generates a dynamic pressure effect, causing the drilling fluid to be squeezed and generate dynamic pressure in the groove. 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 stationary ring 3 moves away from the moving ring 2, thereby further squeezing the compressed gas. At the same time, a liquid film is formed between the stationary ring 3 and the moving ring 2. The liquid film is connected to the gas groove 43 through multiple slide grooves 42, so that the multiple slide grooves 42 are subjected to the same pressure of compressed gas. This ensures that the multiple piston rods 422 provide the same pressure to the stationary ring 3, preventing uneven pressure on the stationary ring 3 from causing the liquid film to fail to form or become unstable.

[0041] Example 2

[0042] In actual use, it was found that when the rotating ring rotates at high speed, the drilling fluid viscosity decreases due to the increase in temperature, and the medium inside the liquid film leaks due to the centrifugal force. Further improvements were made based on the above embodiments.

[0043] Based on the above embodiments, during use, when the moving ring 2 rotates at low speed, due to the high viscosity of the drilling fluid, the second guide groove 22 shears the high-viscosity drilling fluid to form a stable liquid film. The rotation of the moving ring 2 causes the inert gas to be compressed through the first guide groove 21. Since the formation of the liquid and gas films is positively correlated with the viscosity coefficient of the medium and the rotation speed, and the viscosity of the inert gas is low, when the moving ring 2 rotates at low speed, the inert gas cannot form an effective gas film. At this time, the inert gas only flows between the moving ring 2 and the stationary ring 3, affecting the tightness between the stationary ring 3 and the moving ring 2. The cover is cooled down. When the moving ring 2 rotates at high speed, the inert gas forms a gas film between the sealing surfaces of the moving ring 2 and the stationary ring 3 due to dynamic pressure. Since the first guide groove 21 is on the outer wall of the moving ring 2 and the second guide groove 22 is on the inner wall of the moving ring 2, the gas film is on the outer layer of the liquid film, thus 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 moving ring 2 to the inside of the moving ring 2, the gas film squeezes the liquid film towards the inside of the moving ring 2, thereby preventing leakage of the medium inside the liquid film due to centrifugal force when the moving ring 2 rotates at high speed.

[0044] Example 3

[0045] Based on the above embodiments, this embodiment also provides a processing technology for metal seals used in oil and gas drilling rigs, including the following specific steps:

[0046] S1. Machining the moving ring 2 and stationary ring 3: The blank is machined using a machining center to produce the moving ring 2 and stationary ring 3 with the corresponding parameters.

[0047] S2. Machining the first guide groove 21 and the second guide groove 22;

[0048] S3. Machining the stationary ring seat 41: The blank is machined using a CNC machine tool to produce the stationary ring seat 41 with the corresponding parameters, and the through hole on the outer wall of the air groove 43 is machined using a drilling machine.

[0049] S4. Machining the shell 1: Use a CNC machine tool to machine the blank to produce the shell 1 with the corresponding parameters, and use a drilling machine to machine the air holes and clearance holes on the outer wall of the shell 1.

[0050] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A metal seal for oil and gas rigs, comprising a housing (1), characterized in that, Also include: The dynamic ring (2) and static ring (3) are arranged inside the shell (1); Adjusting assembly (4) is arranged at the end of the static ring (3) away from the dynamic ring (2), when the dynamic ring (2) is static, the adjusting assembly (4) can be tightly attached to the end surface of the dynamic ring (2) by extruding the static ring (3), the adjusting assembly (4) can balance the pressure on the static ring (3); The end surface 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 low speed, the second guide groove (22) can extrude the internal medium to form a liquid film, when the dynamic ring (2) rotates at high speed, the first guide groove (21) can compress the external gas to form a gas film.

2. The metal seal for a hydrocarbon drilling rig of claim 1, wherein: The first guide groove (21) and the second guide groove (22) are both multiple and circumferentially arrayed on the end surface of the dynamic ring (2) close to the static ring (3), the opening of the first guide groove (21) is arranged on the outer wall of the dynamic ring (2), and the opening of the second guide groove (22) is arranged on the inner wall of the dynamic ring (2).

3. The metal seal for a hydrocarbon drilling rig of claim 2, wherein: The adjusting assembly (4) comprises a static ring seat (41) arranged inside the shell (1), a sliding groove (42) is arranged inside the static ring seat (41), a piston plate (421) is slidably connected inside the sliding groove (42), one end of the piston plate (421) is fixedly connected with a piston rod (422), and the other end of the piston rod (422) away from the piston plate (421) is fixedly connected with the static ring (3).

4. The metal seal for a hydrocarbon drilling rig of claim 3, wherein: The sliding groove (42) is multiple and circumferentially arrayed, a gas groove (43) is arranged inside the static ring seat (41), and the gas groove (43) is communicated with the multiple sliding grooves (42) through a pipeline.

5. The metal seal for a hydrocarbon drilling rig of claim 4, wherein: The width of the first guide groove (21) gradually decreases from the outer wall of the dynamic ring (2) to the inner wall of the dynamic ring (2), and the width of the second guide groove (22) gradually decreases from the inner wall of the dynamic ring (2) to the outer wall of the dynamic ring (2).

6. The metal seal for a hydrocarbon drilling rig of claim 5, wherein: The dynamic ring (2) is rotatably connected with one end of the shell (1), the static ring seat (41) is fixedly connected with the other end of the shell (1) away from the dynamic ring (2), the inside of the shell (1) is filled with inert gas, and the side wall of the shell (1) is provided with a gas hole for supplementing the inert gas.

7. The metal seal for a hydrocarbon drilling rig of claim 6, wherein: The inside of the gas groove (43) is provided with compressed gas, and the outer wall of the gas groove (43) is provided with a through hole for adjusting the gas pressure inside the gas groove (43).

8. The metal seal for a hydrocarbon drilling rig of claim 7, wherein: The inside of the dynamic ring (2) and the static ring (3) is provided with a sealing ring for preventing the leakage of the internal medium, and the two sealing rings are respectively arranged at the two ends of the contact surface of the dynamic ring (2) and the static ring (3).

9. The metal seal for a hydrocarbon drilling rig of claim 8, wherein: The outer wall of the shell (1) is provided with a relief hole corresponding to the through hole of the gas groove (43).

10. A process for machining a metal seal for oil and gas rigs, the process for machining a metal seal for oil and gas rigs as claimed in claim 9, characterized in that, The method comprises the following steps: S1. Machining dynamic ring (2) and static ring (3), using machining center to process blank, making dynamic ring (2) and static ring (3) with corresponding parameters; S2. Machining first guide groove (21) and second guide groove (22); S3. Machining static ring seat (41), using numerical control machine tool to process blank to process, making corresponding parameter static ring seat (41), and using drilling machine to process through hole of outer wall of air groove (43); S4. Machining shell (1), using numerical control machine tool to process blank to process, making corresponding parameter shell (1), and using drilling machine to process air hole and avoiding hole of outer wall of shell (1).

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