A casing head metal seal assembly with stress self-adapting compensation function

Abstract

The present application relates to the technical field of oil and gas well wellhead sealing. And disclose a kind of casing head metal seal assembly with stress self-adapting compensation function, including casing head body, metal seal ring, annular support base and multiple groups of independent self-adapting support adjusting mechanism, multiple groups of adjusting mechanism are evenly arranged along the base circumference and mutually independent work. The device is through end built-in sensing structure real-time acquisition sealing contact surface contact stress and fit gap change, rely on gear meshing transmission structure to convert rotary power into vertical accurate lifting displacement, can independently complete adaptive height fine adjustment according to each point sealing state, real-time balanced sealing ring circumferential stress distribution, compensate the sealing defect caused by assembly error, temperature deformation and load fluctuation. Gear transmission has reverse self-locking characteristics simultaneously, can effectively lock adjusting position, avoid structure rebound deviation under high pressure working condition. Effectively improve the problem of local stress concentration, significantly improve the sealing stability of casing head and equipment service life.

Description

Technical Field

[0001] This invention relates to the field of wellhead sealing technology for oil and gas wells, specifically to a casing head metal sealing assembly with stress adaptive compensation function. Background Technology

[0002] The casing head is the core pressure-bearing and sealing device at the wellhead of an oil and gas well. It plays a crucial role in casing suspension, pressure isolation, and wellhead sealing. Its sealing reliability directly determines the safe production and long-term seepage prevention capability of oil and gas wells.

[0003] Currently, conventional casing head metal sealing structures mostly adopt an integral rigid support form, with the sealing components and support structure in a fixed assembly state, lacking dynamic adaptive adjustment capabilities. In actual working conditions, due to equipment processing and assembly errors, casing installation coaxiality deviations, formation pressure fluctuations, alternating high and low temperatures, and uneven wellhead loads, stress concentration and uneven stress distribution are prone to occur on the sealing contact surface. Excessive local stress can lead to plastic crushing and wear failure of the seal, while low-stress contact areas are prone to problems such as incomplete sealing and micro-leakage of the medium.

[0004] Existing compensation structures mostly rely on hydraulic drive or overall elastic compensation, which generally suffer from problems such as complex structure, poor environmental adaptability, high failure rate, and high maintenance cost. They cannot independently and accurately compensate for the differentiated gaps and stress defects at different points around the sealing ring, making it difficult to achieve stress-balanced sealing across the entire area. Furthermore, their long-term sealing stability is insufficient, failing to meet the long-term sealing requirements under high pressure and alternating load conditions. Therefore, this invention proposes a bushing head metal seal assembly with stress adaptive compensation function to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a bushing head metal sealing assembly with stress adaptive compensation function to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a casing head metal sealing assembly with stress adaptive compensation function, comprising multiple sets of independent adaptive support adjustment mechanisms, an annular support base, a casing head body and a metal sealing ring, wherein the annular support base is fixedly installed in the sealing installation position inside the casing head body, and the metal sealing ring is mounted above the annular support base to achieve sealing and fitting of the casing head end face; Multiple sets of adaptive support adjustment mechanisms are evenly arranged along the circumference of the annular support base. Each set of adaptive support adjustment mechanisms works independently and does not interfere with each other. Through independent upward displacement adjustment, they adaptively match the sealing gap and contact stress at each point of the metal sealing ring to achieve full-area sealing fit compensation. The adaptive support adjustment mechanism includes a drive component and a vertical height adjustment component. The drive component is located at the bottom of the vertical height adjustment component and is used to realize the bottom rotation drive action. The rotational motion is converted into vertical linear motion, driving the vertical height adjustment component to complete the vertical lifting displacement adjustment. The vertical height adjustment component is vertically assembled in the mounting groove of the annular support base, and a stress-sensing support end is fixedly connected to the top of the vertical height adjustment component; The top surface of the stress-sensing support end is in close contact with the bottom surface of the metal sealing ring, which can accurately sense the contact stress and contact gap at each point in the circumference of the metal sealing ring in real time. Based on the deviation of the real-time stress data, it can complete the independent adaptive compensation adjustment at each point to achieve high-precision closed-loop stress-balanced sealing.

[0007] As a preferred embodiment of the present invention, the driving component includes a base, a hollow block is fixedly connected to the top of the base, a driving block is correspondingly connected to the hollow part inside one side of the hollow block, and a first gear is movably connected to the top output shaft end of the driving block.

[0008] As a preferred embodiment of the present invention, a second gear is meshed with the outer surface of the first gear, a movable disk is connected to the top of the second gear, and the bottom of the movable disk is movably fitted to the top of the hollow block. A vertical height adjustment component is connected to the top outer surface of the movable disk, and a motor is driven to the bottom of the second gear.

[0009] As a preferred embodiment of the present invention, the vertical height adjustment component includes a hollow shell, the bottom of which is fixedly connected to the outer surface of the top of the movable disc, a threaded rod is connected through the center of the hollow shell, and the bottom end of the threaded rod is connected to the center of the top of the second gear. A first fixed disc is threadedly connected to the outer surface of the threaded rod.

[0010] As a preferred embodiment of the present invention, the first fixed disk is slidably connected to four ends of the first long rod, and four symmetrically arranged second long rods are fixedly connected to the top end face of the first fixed disk. The outer surface of the center of the four second long rods and the top end are respectively movably sleeved with the second fixed disk and the connecting plate.

[0011] As a preferred technical solution of the present invention, the top end face of the connecting plate is fixedly connected to the bottom end face of the stress-sensing support. The connecting plate is a circular pressure-bearing plate with uniform overall pressure bearing, which can completely transfer the vertical adjustment thrust to the stress-sensing support end, ensuring that the end is subjected to stable force and without eccentric load.

[0012] As a preferred technical solution of the present invention, the stress-sensing support end adopts an arc-shaped fitting structure that is perfectly adapted to the bottom surface of the metal sealing ring. The end has a built-in stress-sensing sensor, which can collect contact stress data and sealing gap data at each point in real time, providing a precise control basis for the start-stop and forward / reverse adjustment of the drive component, and realizing closed-loop adaptive compensation adjustment.

[0013] As a preferred technical solution of the present invention, the first gear and the second gear adopt a helical gear meshing transmission structure, which has a small meshing gap, high transmission accuracy, and reverse self-locking performance. This can effectively prevent the vertical height adjustment component from being squeezed by sealing pressure and causing reverse displacement, thus ensuring the stability of the support height and sealing accuracy after adjustment.

[0014] Compared with the prior art, the beneficial effects of the present invention are: A bushing head metal sealing assembly with stress adaptive compensation function adopts a motor-driven, helical gear meshing transmission structure with a first gear and a second gear. It achieves stable output of rotational power by relying on the principle of gear reduction and torque amplification. It has small transmission clearance, high adjustment resolution, and uniform power transmission, and can achieve precise adjustment of small strokes. At the same time, the helical gear meshing has excellent reverse self-locking performance, which can completely offset the reverse extrusion force generated during the high-pressure bearing process of the metal sealing ring, effectively preventing the vertical height adjustment component from being displaced in the opposite direction of pressure and the problem of height rebound.

[0015] A sleeve head metal sealing assembly with stress adaptive compensation function uses a threaded rod and threaded transmission combined with a multi-set symmetrical guide and limiting structure consisting of a first long rod, a second long rod, and a second fixed plate to precisely convert rotational motion into vertical linear lifting motion. This effectively limits radial offset, swaying, and deflection during the adjustment process, resulting in smooth lifting and lowering operation with minimal adjustment error. At the same time, the connecting plate of the top circular pressure-bearing structure achieves uniform force distribution, transferring the vertical thrust completely and evenly to the stress-sensitive support end, avoiding structural deformation caused by stress concentration at a single point.

[0016] A bushing head metal sealing assembly with stress adaptive compensation function can collect real-time and accurate data on contact stress and sealing gap at various points of the metal sealing ring through a stress sensing sensor built into the stress sensing support end. It can dynamically adapt to changes in working conditions and automatically compensate for potential sealing failures caused by assembly errors, bushing deformation, and pressure and temperature fluctuations.

[0017] A casing head metal sealing assembly with stress adaptive compensation function uses multiple sets of independent adaptive support adjustment mechanisms evenly distributed along the circumference of the annular support base. Each set of mechanisms does not interfere with each other and responds independently to stress changes at the point. It can achieve precise lifting and lowering adjustment at a single point to address problems such as single-point stress concentration or uneven fitting gap caused by machining errors of the metal sealing ring, assembly coaxiality deviation, alternating load at the wellhead, and temperature deformation. It completely breaks through the defects of traditional integral rigid support, such as stress concentration, local crushing, and local micro-leakage, and achieves uniform distribution of contact stress throughout the circumference of the metal sealing ring. Attached Figure Description

[0018] Figure 1 This is a top view of the structure of the present invention; Figure 2 This is a schematic diagram of the front structure of the present invention; Figure 3 This is a schematic diagram of the overall adaptive support adjustment mechanism of the present invention; Figure 4 This is a schematic diagram of the internal connection relationship of the adaptive support adjustment mechanism of the present invention; Figure 5 This is a schematic diagram of the driving component of the present invention; Figure 6 This is a schematic diagram showing the connection between the movable disk and the hollow shell of the present invention; Figure 7 This is a schematic diagram of the vertical height adjustment component of the present invention; Figure 8 This is a schematic diagram showing the connection relationship between the second gear and the threaded rod in this invention.

[0019] In the diagram: 1. Adaptive support adjustment mechanism; 11. Drive assembly; 111. Base; 112. Hollow block; 113. Drive block; 114. First gear; 115. Second gear; 116. Moving disc; 117. Motor; 12. Vertical height adjustment assembly; 121. Hollow shell; 122. Threaded rod; 123. First fixed disc; 124. First long rod; 125. Second long rod; 126. Second fixed disc; 127. Connecting plate; 13. Stress-sensing support end; 131. Stress-sensing sensor; 2. Annular support base; 3. Sleeve head body; 4. Metal sealing ring. Detailed Implementation

[0020] 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example: Please refer to Figure 1-2 A casing head metal sealing assembly with stress adaptive compensation function includes multiple independent adaptive support adjustment mechanisms 1, annular support base 2, casing head body 3 and metal sealing ring 4. The annular support base 2 is fixedly installed in the sealing installation position inside the casing head body 3, and the metal sealing ring 4 is mounted above the annular support base 2 to achieve sealing and fitting of the casing head end face. Multiple sets of adaptive support adjustment mechanisms 1 are evenly arranged around the annular support base 2. Each set of adaptive support adjustment mechanisms 1 works independently and does not interfere with each other. Through independent upward displacement adjustment, they adaptively match the sealing gap and contact stress at each point of the metal sealing ring 4 to achieve full-area sealing fit compensation. The adaptive support adjustment mechanism 1 includes a drive component 11 and a vertical height adjustment component 12. The drive component 11 is located at the bottom of the vertical height adjustment component 12 and is used to realize the bottom rotation drive action. The rotational motion is converted into vertical linear motion, driving the vertical height adjustment component 12 to complete the vertical lifting displacement adjustment. The vertical height adjustment component 12 is vertically assembled in the mounting groove of the annular support base 2, and a stress-sensing support end 13 is fixedly connected to the top of the vertical height adjustment component 12. The top surface of the stress-sensing support end 13 is in close contact with the bottom surface of the metal sealing ring 4, which can accurately sense the contact stress and contact gap at each point around the metal sealing ring 4 in real time. Based on the deviation of the real-time stress data, it can complete the independent adaptive compensation adjustment at each point to achieve high-precision closed-loop stress-balanced sealing.

[0022] Example 2: Based on Example 1, as follows Figure 3-8 As shown, the drive assembly 11 includes a base 111, a hollow block 112 is provided on the top of the base 111, and the top of the base 111 is fixedly connected to the bottom of the hollow block 112. A drive block 113 is provided in the hollow part on one side of the hollow block 112, and the hollow part on one side of the hollow block 112 is correspondingly connected to the bottom of the drive block 113. A first gear 114 is provided at the top output shaft end of the drive block 113, and the top output shaft end of the drive block 113 is movably connected to the center of the first gear 114.

[0023] The outer surface of the first gear 114 is provided with a second gear 115, and the outer surfaces of the first gear 114 and the second gear 115 are meshed and connected. The top of the second gear 115 is provided with a movable disk 116, and the top of the second gear 115 is connected to the bottom of the movable disk 116. The bottom of the movable disk 116 is movably fitted and connected to the top of the hollow block 112. The outer surface of the top of the movable disk 116 is provided with a vertical height adjustment component 12, and the outer surface of the top of the movable disk 116 is connected to the bottom of the vertical height adjustment component 12. The bottom of the second gear 115 is provided with a motor 117, and the bottom of the second gear 115 is drivenly connected to the output shaft end of the motor 117. By adopting a helical gear transmission structure driven by motor 117 and first gear 114 and second gear 115, the rotational power is smoothly output by relying on the principle of gear reduction and torque increase. The transmission gap is small, the adjustment resolution is high, and the power transmission is uniform. It can achieve precise adjustment of small strokes. At the same time, the helical gear meshing has excellent reverse self-locking performance, which can completely offset the reverse extrusion force generated by the metal sealing ring 4 during high pressure, effectively preventing the vertical height adjustment component 12 from being displaced in the opposite direction of pressure and the height rebound problem.

[0024] The vertical height adjustment component 12 includes a hollow shell 121. The bottom of the hollow shell 121 is fixedly connected to the top outer surface of the movable disc 116. A threaded rod 122 is correspondingly provided at the center of the hollow shell 121, and the center of the hollow shell 121 is connected through the outer surface of the threaded rod 122. The bottom end of the threaded rod 122 is connected to the top center of the second gear 115. A first fixed disc 123 is threadedly provided on the outer surface of the threaded rod 122, and the threaded outer surface of the threaded rod 122 is movably connected to the center of the first fixed disc 123.

[0025] The first fixed plate 123 is provided with a first long rod 124 at each of its four ends, and the four ends of the first fixed plate 123 are slidably connected to the outer surface of the first long rod 124. The top end face of the first fixed plate 123 is provided with four symmetrically arranged second long rods 125, and the top end face of the first fixed plate 123 is fixedly connected to the bottom of the four symmetrically arranged second long rods 125. The outer surface of the center of the four second long rods 125 and the top end are respectively movably sleeved with a second fixed plate 126 and a connecting plate 127. By using the threaded rod 122 for threaded transmission and cooperating with the first long rod 124, the second long rod 125 and the second fixed plate 126 to form a multi-set symmetrical guide and limiting structure, the rotational motion is accurately converted into vertical linear lifting motion, effectively limiting the radial offset, swaying and deflection problems during the adjustment process. The lifting operation is smooth and the adjustment error is minimal. At the same time, the connecting plate 127 with the top circular bearing structure realizes the uniform distribution of force, and transmits the vertical thrust completely and evenly to the stress-sensitive support end 13, avoiding structural deformation caused by stress concentration at a single point.

[0026] The top end face of the connecting plate 127 is fixedly connected to the bottom surface of the stress-sensing support end 13. The connecting plate 127 is a circular pressure-bearing plate with uniform overall pressure, which can completely transfer the vertical adjustment thrust to the stress-sensing support end 13, ensuring that the end is subjected to stable force and without eccentric load. Through the stress-sensing sensor 131 built into the stress-sensing support end 13, the contact stress and sealing gap data of each point of the metal sealing ring 4 can be collected in real time and accurately, dynamically adapting to changes in working conditions and automatically compensating for potential sealing failures caused by assembly errors, sleeve deformation, and pressure and temperature fluctuations.

[0027] The stress-sensing support end 13 adopts an arc-shaped fitting structure that is perfectly adapted to the bottom surface of the metal sealing ring 4. The end has a built-in stress-sensing sensor 131, which can collect contact stress data and sealing gap data at each point in real time, providing a precise control basis for the start-stop and forward / reverse adjustment of the drive component 11, and realizing closed-loop adaptive compensation adjustment.

[0028] The first gear 114 and the second gear 115 adopt a helical gear meshing transmission structure with small meshing gap, high transmission accuracy, and reverse self-locking performance, which can effectively prevent the vertical height adjustment component 12 from being squeezed by sealing pressure and causing reverse displacement, thus ensuring the stability of the support height and sealing accuracy after adjustment.

[0029] The working principle of this invention is as follows: During operation, the adaptive support adjustment mechanism 1, which is evenly distributed and independent along the circumference of the ring support base 2, achieves the full-domain closed-loop stress adaptive compensation sealing function. After the equipment is properly assembled, the annular support base 2 is fixed to the sealing position inside the sleeve head body 3. The metal sealing ring 4 is stably mounted on the stress-sensing support end 13 at the top of each adaptive support adjustment mechanism 1. The stress-sensing support end 13 adopts an arc-shaped fitting structure that is completely adapted to the bottom surface of the metal sealing ring 4. The stress-sensing sensor 131 built into it can collect the contact stress value and sealing gap change data of each point in the circumference of the metal sealing ring 4 in real time and all day long, and transmit the collected analog signal to the control system in real time for calculation and analysis. When the metal sealing ring 4 experiences uneven stress conditions such as local stress overload, excessive fitting gap, insufficient local stress, or excessively tight fitting due to processing and assembly errors, casing coaxiality deviation, wellhead pressure fluctuation, temperature alternation, and uneven load, the control system independently issues control commands based on the stress difference at each point, and the drive component 11 at the corresponding abnormal point starts working. The motor 117 at the bottom of the drive assembly 11 outputs rotational power and drives the second gear 115 to rotate. The second gear 115 and the first gear 114 form a helical gear meshing transmission structure. Relying on the characteristics of small meshing clearance, high transmission accuracy, deceleration and torque increase and reverse self-locking of helical gears, a smooth and accurate power output is achieved, which effectively avoids transmission error and the problem of reverse displacement and springback of vertical structure under high pressure conditions. During the rotation of the second gear 115, the threaded rod 122 in the vertical height adjustment assembly 12 is moved synchronously. When the vertical height adjustment component 12 is working, the threaded rod 122, through threaded transmission and in cooperation with the first fixed plate 123, achieves precise conversion of rotational motion into vertical linear lifting motion. At the same time, the first long rod 124, which is slidably connected through the four ends of the first fixed plate 123, the four second long rods 125 fixed at the top, and the matching second fixed plate 126 together form multiple sets of symmetrical guide and limit structures, which effectively limit radial offset, structural sway and angular deflection during the vertical lifting adjustment process, and ensure that the lifting adjustment is smooth and without deviation throughout the entire process. Meanwhile, during the lifting and lowering process of the threaded rod 122, the vertical thrust is evenly transmitted to the stress-sensing support end 13 through the top connecting plate 127. The connecting plate 127 adopts a circular pressure-bearing plate structure, which can achieve uniform distribution of force throughout the entire area, completely eliminating local eccentric load and stress concentration deformation. For the stress overload point of the metal sealing ring 4, the corresponding drive component 11 drives the downward support height of the stress-sensing support end 13 in the forward direction to disperse the local concentrated stress. For the point where the metal sealing ring 4 has a large fitting gap and insufficient stress; The drive component 11 reverses the drive to raise the support height of the stress-sensing support end 13, making up for the sealing pressure. Through the independent point fine adjustment of each group of adaptive support adjustment mechanisms 1, the differential sealing gap and contact stress of each point of the metal sealing ring 4 are matched in real time, continuously correcting the sealing defects caused by working condition deformation and assembly deviation. The entire process relies on the real-time feedback data of the stress-sensing sensor 131 to form a closed-loop adaptive control, always maintaining the uniform fit and balanced stress distribution of the metal sealing ring 4 in the circumferential region, and stably achieving high-precision and long-lasting metal sealing inside the sleeve head body 3. At the same time, the self-locking performance of the helical gear meshing can lock the support height after adjustment, ensuring the long-term stability and sealing accuracy of the sealing structure under high-pressure alternating working conditions.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A casing head metal sealing assembly with stress adaptive compensation function, comprising multiple sets of independent adaptive support adjustment mechanisms (1), an annular support base (2), a casing head body (3), and a metal sealing ring (4), characterized in that: The annular support base (2) is fixedly installed inside the sleeve head body (3) at the sealing installation position, and the metal sealing ring (4) is erected above the annular support base (2) to achieve sealing and fitting of the sleeve head end face; Multiple sets of adaptive support adjustment mechanisms (1) are evenly arranged around the annular support base (2). Each set of adaptive support adjustment mechanisms (1) works independently and does not interfere with each other. Through independent upward displacement adjustment, they adaptively match the sealing gap and contact stress at each point of the metal sealing ring (4). The adaptive support adjustment mechanism (1) includes a drive component (11) and a vertical height adjustment component (12). The drive component (11) is located at the bottom of the vertical height adjustment component (12) and is used to realize the bottom rotation drive action. The rotational motion is converted into vertical linear motion, driving the vertical height adjustment component (12) to complete the vertical lifting displacement adjustment. The vertical height adjustment component (12) is vertically assembled in the mounting groove of the annular support base (2), and a stress-sensitive support end (13) is fixedly connected to the top of the vertical height adjustment component (12). The top surface of the stress-sensing support end (13) is in contact with the bottom surface of the metal sealing ring (4), and can accurately sense the contact stress and the fitting gap at each point in the circumference of the metal sealing ring (4) in real time.

2. The bushing head metal sealing assembly with stress adaptive compensation function according to claim 1, characterized in that: The drive assembly (11) includes a base (111), a hollow block (112) is fixedly connected to the top of the base (111), a drive block (113) is correspondingly connected to the hollow part inside one side of the hollow block (112), and a first gear (114) is movably connected to the top output shaft end of the drive block (113).

3. A bushing head metal sealing assembly with stress adaptive compensation function according to claim 2, characterized in that: The outer surface of the first gear (114) is meshed with a second gear (115). The top of the second gear (115) is connected to a movable disc (116), and the bottom of the movable disc (116) is movably fitted to the top of the hollow block (112). The top outer surface of the movable disc (116) is connected to a vertical height adjustment component (12), and the bottom of the second gear (115) is connected to a motor (117).

4. A bushing head metal sealing assembly with stress adaptive compensation function according to claim 3, characterized in that: The vertical height adjustment component (12) includes a hollow shell (121), the bottom of which is fixedly connected to the top outer surface of the movable disc (116), a threaded rod (122) is correspondingly connected through the center of the hollow shell (121), and the bottom end of the threaded rod (122) is connected to the top center of the second gear (115), and a first fixed disc (123) is threadedly connected to the outer surface of the threaded rod (122).

5. A bushing head metal sealing assembly with stress adaptive compensation function according to claim 4, characterized in that: The first fixed plate (123) is slidably connected to the four ends of the first long rod (124). The top end face of the first fixed plate (123) is fixedly connected to four symmetrically arranged second long rods (125). The outer surface of the center of the four second long rods (125) and the top end are respectively movably sleeved with the second fixed plate (126) and the connecting plate (127).

6. A bushing head metal sealing assembly with stress adaptive compensation function according to claim 5, characterized in that: The top end face of the connecting plate (127) is fixedly connected to the bottom surface of the stress-sensing support end (13). The connecting plate (127) is a circular pressure-bearing plate with uniform overall pressure, which can completely transmit the vertical adjustment thrust to the stress-sensing support end (13).

7. A casing head metal sealing assembly with stress adaptive compensation function according to claim 1, characterized in that: The stress-sensing support end (13) adopts an arc-shaped fitting structure that is fully adapted to the bottom surface of the metal sealing ring (4), and the end has a built-in stress-sensing sensor (131).

8. A bushing head metal sealing assembly with stress adaptive compensation function according to claim 3, characterized in that: The first gear (114) and the second gear (115) adopt a helical gear meshing transmission structure, which can effectively prevent the vertical height adjustment component (12) from being squeezed by the sealing pressure and causing reverse displacement.

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