Thermal recovery casing head

Abstract

The invention relates to the technical field of thermal recovery casing heads, and discloses a thermal recovery casing head which comprises a casing head body. The plurality of flange supports are circumferentially and uniformly distributed at the bottom of the casing head main body and are fixedly welded with the casing head main body, and one side of each flange support is provided with a shrinkage groove; the mounting bottom plate is fixed to the bottom of the flange support, a plurality of arc-shaped plates extending downwards are arranged at the bottom of the mounting bottom plate, and the outer diameter of each arc-shaped plate is smaller than the inner diameter of the oil well opening to form a mounting gap. The auxiliary supporting mechanism is arranged on the flange support, the insertion depth of the stretching body can be dynamically adjusted, ground subsidence or collapse can be compensated in real time, it is ensured that a casing head mounting base plane is always in a stable state, and casing column deflection or stress concentration caused by ground deformation is avoided; and through an inclined supporting system formed by the supporting body and the ground, the weight and thermal cycle stress of the casing head are effectively dispersed, and through the combination of double fixation of the sawtooth groove-shaped structure and the locking assembly, the bolt loosening risk caused by vibration is greatly reduced, and creep deformation and deterioration of materials are restrained.

Description

Technical Field

[0001] The invention relates to the technical field of thermal recovery casing heads, and more particularly to a thermal recovery casing head. Background Art

[0002] The oil well thermal recovery connection casing head is a special wellhead device designed for heavy oil thermal recovery processes (such as steam drive, SAGD). Its core function is to achieve casing string suspension, annulus sealing and wellhead connection under high temperature, high pressure and thermal cycle conditions. The device adopts a high temperature resistant alloy body, a metal / graphite composite sealing system and a thermal expansion compensation structure (such as a sliding hanger or a bellows), which can dynamically adjust the expansion and contraction stress caused by temperature changes, and is equipped with redundant seals and anti-creep flanges, effectively solving the problems of sealing failure, bolt loosening and material degradation of traditional casing heads in thermal recovery, and is a key component to ensure the safe and efficient operation of thermal recovery wells.

[0003] In heavy oil thermal recovery processes (such as steam drive), oil wells need to withstand high temperature, high pressure and periodic thermal stress shocks for a long time, which places extremely high demands on the stability of wellhead devices. Although traditional thermal recovery casing heads use high-temperature resistant alloys, metal / graphite composite seals and thermal expansion compensation structures (such as bellows) to deal with high-temperature deformation and seal failure problems, there are still significant defects in practical applications: First, the formations around the oil wellhead are prone to slight collapse or settlement due to thermal recovery operations, resulting in the inclination or displacement of the casing head installation base, causing uneven force on the casing column and limited activity, which in turn exacerbates the risk of seal failure and bolt loosening; second, the support structure of the existing casing head is mostly a rigid fixed design, which cannot dynamically compensate for ground settlement, resulting in stress concentration at the connection between the casing head and the wellhead, accelerating material creep degradation, and even causing wellhead leakage accidents. Therefore, there is an urgent need for a thermal recovery casing head with ground adaptive compensation capability, dynamic adjustment of support stress and improved seismic stability to ensure safe and efficient operation of the oil wellhead under extreme working conditions. Summary of the invention

[0004] The purpose of the present invention is to provide a thermal recovery casing head to solve the above-mentioned technical problems.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions:

[0006] The present invention provides a thermal recovery casing head, comprising:

[0007] Casing head body;

[0008] A plurality of flange supports are evenly distributed on the circumference of the bottom of the casing head body and are welded and fixed thereto, and a shrinkage groove is provided on one side of each flange support;

[0009] The installation base plate is fixed to the bottom of the flange support, and a plurality of arc-shaped plates extending downward are provided at the bottom thereof, wherein the outer diameter of the arc-shaped plates is smaller than the inner diameter of the oil well mouth to form an installation gap;

[0010] A plurality of auxiliary support mechanisms, including:

[0011] A support body, one end of which is hinged in the contraction groove;

[0012] An extension body is slidably disposed in the support body;

[0013] The extension drive assembly is arranged on the support body and is transmission-connected to the extension body, and is used to drive the extension body to slide linearly along the support body;

[0014] A locking assembly, used to lock the support body in an expanded or contracted state;

[0015] When the support body is unfolded, it forms a preset angle with the ground, and the bottom of the extended body can be inserted into the ground to form a stable support.

[0016] As a further optimization scheme of the present invention, the extension drive assembly includes a screw, a drive knob and a bevel gear set meshing with each other, the screw is threadedly connected to the extension body, and the bevel gear set converts the rotational motion of the drive knob into rotation of the screw.

[0017] As a further optimization solution of the present invention, a sawtooth groove structure is provided at the bottom of the extension body.

[0018] As a further optimization solution of the present invention, the locking assembly includes a locking screw and threaded holes located on both sides of the inner wall of the shrinkage groove, and the locking screw is screwed into the corresponding threaded hole to fix the position of the support body.

[0019] As a further optimization scheme of the present invention, a fine-tuning assembly is provided in the mounting hole of the mounting base plate, including a sleeve, a plurality of contact cams and a support spring. The contact cam elastically abuts against the bolt through the support spring to provide a fine-tuning space.

[0020] As a further optimization solution of the present invention, the number of the contact protrusions is six, and the six contact protrusions are evenly distributed around the circumference.

[0021] As a further optimization solution of the present invention, one end of the contact cam facing the axis of the sleeve is an arc surface, and a wear-resistant coating is provided on the arc surface.

[0022] As a further optimization solution of the present invention, a damping structure is provided between the sleeve and the bolt.

[0023] As a further optimization solution of the present invention, the angle between the flange support and the casing head body is 40-45°, and the angle between the mounting base plate and the flange support is 50-55°.

[0024] As a further optimization solution of the present invention, the number of the arc-shaped plates is five, and the five arc-shaped plates are evenly distributed around the circumference.

[0025] The beneficial effects of the present invention are:

[0026] The present invention arranges an auxiliary supporting mechanism on the flange support, which can dynamically adjust the insertion depth of the extension body, compensate for ground settlement or collapse in real time, ensure that the casing head installation base is always in a stable state, and avoid casing column deflection or stress concentration caused by ground deformation; and the inclined supporting system formed by the supporting body and the ground can effectively disperse the weight of the casing head and the thermal cycle stress, and the double fixation of the serrated groove structure and the locking assembly can greatly reduce the risk of bolt loosening caused by vibration, and inhibit material creep degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a thermal recovery casing head provided by the present invention;

[0028] Figure 2 It is a structural schematic diagram of a thermal recovery casing head provided by the present invention after being installed with an oil wellhead;

[0029] Figure 3 It is a structural schematic diagram of a flange support and an auxiliary support mechanism in a thermal recovery casing head provided by the present invention;

[0030] Figure 4 It is a structural schematic diagram of an auxiliary support mechanism in a thermal recovery casing head provided by the present invention;

[0031] Figure 5 It is a cross-sectional view of a support body in a thermal recovery casing head provided by the present invention;

[0032] Figure 6 It is a structural schematic diagram of a flange support in a thermal recovery casing head provided by the present invention;

[0033] Figure 7 It is a structural schematic diagram of a local position of an installation base plate in a thermal recovery casing head provided by the present invention;

[0034] Figure 8 It is a cross-sectional view of a fine-tuning component in a thermal recovery casing head provided by the present invention.

[0035] In the figure:

[0036] 1. Casing head body; 2. Flange support; 21. Contraction groove; 3. Mounting base plate; 31. Arc plate; 4. Auxiliary support mechanism; 41. Support body; 42. Extension body; 421. Sawtooth groove structure; 43. Extension drive assembly; 431. Screw; 432. Drive knob; 433. Bevel gear set; 44. Locking assembly; 441. Locking screw; 442. Threaded hole; 5. Fine-tuning assembly; 51. Sleeve; 52. Contact cam; 53. Support spring; 6. Oil wellhead. DETAILED DESCRIPTION

[0037] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0038] Please refer to Figures 1 to 3 A thermal recovery casing head comprises: a casing head body 1, six flange supports 2, six auxiliary support mechanisms 4 and a mounting base plate 3. The six flange supports 2 are evenly distributed on the bottom of the casing head body 1, and the flange supports 2 are welded and fixed to the casing head body 1, with an angle of 40-45°. The top of the mounting base plate 3 is welded and fixed to the bottom of the six flange supports 2. The mounting base plate 3 is used to connect to the end face of the oil wellhead 6, and is provided with mounting holes, which are connected with the bolts on the end face of the oil wellhead 6. In addition, the mounting base plate 3 is in the shape of a circular ring, and the angle between it and the flange support 2 is 50-55°, which can form a continuous support arc surface with a total angle of 90-100°, significantly improving the overall bending stiffness. Five downwardly extending arc plates 31 are evenly arranged on the bottom circumference of the installation base plate 3, and the arc plates 31 are adapted to the inner side of the oil well mouth 6. When the installation base plate 3 is docked and installed with the oil well mouth 6, the arc plates 31 first slide with the inner side of the oil well mouth 6, so that the entire thermal recovery casing head and the oil well mouth 6 can be initially aligned, which can speed up the installation of the thermal recovery casing head. The outer diameter of the arc plate 31 differs from the inner diameter of the oil well mouth 6 by 2-4mm. In this way, after the installation base plate 3 is connected to the oil well mouth 6, some gaps will be reserved between the arc plates 31 and the inner wall of the oil well mouth 6. On the one hand, it is convenient to perform precise fine-tuning of the entire casing head later. On the other hand, in actual use, stress is generated inside the arc plate 31 due to high temperature, and when thermal expansion occurs, a certain margin will be left to avoid damage to the inner wall of the oil well mouth 6, which is also more convenient for subsequent disassembly.

[0039] Each flange support 2 is provided with a contraction groove 21 on one side, and six auxiliary support mechanisms 4 are respectively arranged in the six contraction grooves 21. The auxiliary support mechanism 4 will be contracted in the contraction groove 21 when not in use, and used together with the flange support 2 as a supporting structure. When in use, it will be movably unfolded and fixed on the ground, which can be used to improve the supporting effect of the flange support 2 and the extension body 42. The auxiliary support mechanism 4 includes a support body 41, an extension body 42, an extension drive assembly 43 and a locking assembly 44. The end of the support body 41 is hinged to the inner side of the contraction groove 21, and the extension body 42 slides and contracts in the support body 41. After the support body 41 is unfolded, the angle between the support body 41 and the ground is between 45-60°. The extension drive assembly 43 is arranged on the support body 41, and it is connected to the sliding end of the extension body 42 by transmission, and is mainly used to drive the extension body 42 to slide and extend linearly outward along the support body 41. After the extension body 42 stops driving, it can automatically lock the extension body 42 to keep the extension in a fixed state. The locking assembly 44 is used to lock the position of the support body 41 after contraction and extension, so that the support body 41 cannot move.

[0040] It should be noted that when the auxiliary support mechanism 4 is in use, the installation base plate 3 is now installed with the oil wellhead 6. In order to further enhance the installation stability of the casing head body 1, the auxiliary support mechanism 4 can be unfolded. When unfolding, the locking effect on the support body 41 is released by operating the locking component 44, and the support body 41 is unfolded. The unfolded support body 41 extends close to the ground, and the locking component 44 is operated again to lock the unfolded support body 41 to fix it with the flange support 2. Then, the telescopic driving member is operated to drive the extension body 42 to start sliding downward along the support body 41. When the bottom of the extension body 42 is aligned with the flange support 2, the extension body 41 is locked. After contacting the ground, if the ground is a soft soil layer, the extension body 42 can continue to be driven to extend downward so that it can be inserted into the ground until it reaches a stable support point, and the extension drive assembly 43 is stopped. Under the self-locking effect of the extension drive assembly 43, the extension body 42 can be kept fixed. Repeat the operation to fully unfold the six auxiliary support mechanisms 4, so that the auxiliary support mechanisms 4 are connected to the ground, thereby forming a stable support body 41 system, which can effectively disperse the weight and stress of the casing head, reduce the force on the oil wellhead 6, and at the same time improve the anti-seismic effect of the entire casing head, and avoid loosening caused by the vibration generated by the casing activity. In addition, when the oil wellhead 6 has been used for a long time and the surrounding ground has slightly sunk, the extension drive assembly 43 corresponding to the sinking position can be continued to operate to drive the extension body 42 to continue to extend downward, so that the impact of ground sinking can be effectively compensated, ensuring that the casing head is always in a stable state, and playing a good limiting role on the casing. It can be seen that the auxiliary support mechanism 4 is cleverly designed, which not only improves the stability of the casing head, but also has the flexibility to adapt to ground changes, ensuring that the oil wellhead 6 can remain stable in various environments, extending its service life and significantly improving operational safety. In addition, the mechanism can still maintain support force, reduce maintenance frequency, and reduce maintenance costs by adjusting the depth of the extension body 42 during extreme weather or geological changes, providing reliable protection for oil field production. In specific operations, the support body 41 can be quickly deployed and locked by simply manipulating the drive assembly, which is convenient and efficient.

[0041] Please refer to Figures 3 to 5The extension drive assembly 43 includes a screw rod 431, a driving knob 432 and a bevel gear set 433. The screw rod 431 is rotatably mounted in the support body 41. The extension body 42 is threadedly connected to the outer side of the screw rod 431. The driving knob 432 is rotatably mounted on one side of the support body 41. The bevel gear set 433 is composed of two bevel gears, which are respectively fixed to the ends of the screw rod 431 and the driving knob 432, and the two bevel gears are meshed with each other. When the extension body 42 is driven to extend downward, the two bevel gears can be driven to rotate by rotating the driving knob 432, thereby driving the screw rod 431 to rotate. Under the rotation of the screw rod 431, the extension body 42 begins to move downward along the support body 41 until it reaches a predetermined depth. At this time, the self-locking function of the screw rod 431 is activated to ensure that the extension body 42 is stable and immovable. The extension drive assembly 43 transmits power through the meshing of the bevel gears, so that the rotation of the driving knob 432 can be efficiently converted into the rotation of the screw rod 431, thereby accurately controlling the moving distance of the extension body 42. At the same time, the mutual meshing of the bevel gears also enhances the stability of the transmission system, ensuring that the accuracy and reliability of the operation can be maintained under complex geological conditions. This design not only simplifies the operation process, but also greatly improves the adjustment flexibility of the support body 41 system, ensuring that it can quickly adapt to ground changes in various environments, thereby effectively ensuring the long-term stability and safety of the oil wellhead 6.

[0042] Please refer to Figure 4 and Figure 5 The extension body 42 is composed of a sliding part and an extension part. The sliding part matches the inclination of the support body 41, while the extension part fits tightly with the bottom of the extension body 42. A plurality of sawtooth groove structures 421 are provided at the bottom of the extension part to enhance the friction with the ground and prevent sliding. The design of the sawtooth groove structure 421 not only improves the ground grip, but also effectively prevents the displacement of the extension body 42 in soft or slippery soil environments to ensure support stability. The extension body 42 adopts an inclined downward extension method, which can better disperse the ground pressure and reduce the risk of local settlement compared to vertical extension, further enhancing the deformation resistance of the overall structure.

[0043] Please refer to Figure 3 and Figure 6 The locking assembly 44 includes a locking screw 441 and two threaded holes 442 that are connected to the locking rotating rod. The locking rotating rod is threadedly installed on the outside of the support body 41. The two threaded holes 442 are located on both sides of the inner wall of the contraction groove 21. The two threaded holes 442 correspond to the contracted and expanded positions of the support body 41 respectively. The support body 41 is firmly locked by tightening the locking rotating rod with the threaded holes 442 at the corresponding positions.

[0044] Please refer to Figure 1 , Figure 7 and Figure 8A fine-tuning assembly 5 is provided on the mounting hole of the mounting base plate 3. The fine-tuning assembly 5 includes a sleeve 51 and at least six contact cams 52. The outer side of the sleeve 51 is fixed to the inner side of the mounting hole. The six contact cams 52 are evenly distributed on the inner side of the sleeve 51. The end of the contact cam 52 facing the axis of the sleeve 51 is in an arc shape. When it contacts the bolt on the oil well head 6, the friction between the bolt and the contact cam 52 can be reduced. A support spring 53 is connected between the contact cam 52 and the sleeve 51. Since the thermal recovery casing head is in a high temperature environment, the design of the spring stiffness coefficient needs to consider the difference in the thermal expansion coefficient of the material, and the spring stiffness needs to be matched to 300-350N / mm to achieve effective compensation. A damping structure is provided between the sleeve 51 and the bolt to reduce the resonance generated by the contact cam 52. The damping structure, such as filling with silicone-based damping grease (viscosity 1000cSt) or using a wave spring washer, can increase the system damping ratio to above 0.15.

[0045] By providing the fine-tuning component 5, on the one hand, when the mounting base plate 3 and the oil well mouth 6 are fixed, a certain movable space is provided between the mounting hole on the mounting base plate 3 and the bolt, so that the casing head can be fine-tuned. On the other hand, the presence of the support spring 53 can effectively buffer the vibration generated during the installation process, thereby ensuring that the connection between the mounting base plate 3 and the oil well mouth 6 is more stable and the problem of bolt loosening due to vibration is avoided. When the temperature rises and the internal stress of the bolt increases and expands, the slight displacement between the contact cam 52 and the sleeve 51 can effectively release the stress and prevent the bolt from being damaged due to thermal expansion, thereby further improving the durability and safety of the overall structure.

[0046] An example of the present specific implementation mode is described above, but the present embodiment is not limited to the above-mentioned specific implementation mode, which is merely illustrative and not restrictive. A person skilled in the art may make many forms inspired by the present embodiment, all of which are protected by the present embodiment.

Claims

1. A thermal recovery casing head, characterized in that: include: Casing head body (1); A plurality of flange supports (2) are evenly distributed around the circumference of the bottom of the casing head body (1) and are welded and fixed thereto, and a shrinkage groove (21) is provided on one side of each flange support (2); A mounting base plate (3) is fixed to the bottom of the flange support (2), and a plurality of arc-shaped plates (31) extending downward are provided at the bottom thereof, wherein the outer diameter of the arc-shaped plates (31) is smaller than the inner diameter of the oil wellhead to form a mounting gap; A plurality of auxiliary support mechanisms (4), comprising: A support body (41), one end of which is hinged in the shrinkage groove (21); An extension body (42) is slidably disposed in the support body (41); An extension drive assembly (43) is disposed on the support body (41) and is drivingly connected to the extension body (42), and is used to drive the extension body (42) to slide linearly along the support body (41); A locking assembly (44), used for locking the support body (41) in an expanded or contracted state; When the support body (41) is unfolded, it forms a preset angle with the ground, and the bottom of the extension body (42) can be inserted into the ground to form a stable support.

2. A thermal recovery casing head according to claim 1, characterized in that: The extension drive assembly (43) comprises a screw rod (431), a drive knob (432) and a bevel gear set (433) meshing with each other; the screw rod (431) is threadedly connected to the extension body (42); and the bevel gear set (433) converts the rotational motion of the drive knob (432) into the rotation of the screw rod (431).

3. A thermal recovery casing head according to claim 2, characterized in that: The bottom of the extension body (42) is provided with a sawtooth groove structure (421).

4. A thermal recovery casing head according to claim 2, characterized in that: The locking assembly (44) comprises a locking screw (441) and threaded holes (442) located on both sides of the inner wall of the shrinkage groove (21); the locking screw (441) is screwed into the corresponding threaded hole (442) to fix the position of the support body (41).

5. A thermal recovery casing head according to claim 2, characterized in that: A fine-tuning assembly (5) is provided in the mounting hole of the mounting base plate (3), comprising a sleeve (51), a plurality of contact convex shafts (52) and a support spring (53); the contact convex shaft (52) elastically abuts against a bolt via the support spring (53) to provide a fine-tuning space.

6. A thermal recovery casing head according to claim 5, characterized in that: The number of the contact convex shafts (52) is six, and the six contact convex shafts are evenly distributed around the circumference.

7. A thermal recovery casing head according to claim 6, characterized in that: One end of the contact convex shaft (52) facing the axis of the sleeve (51) is an arc surface, and a wear-resistant coating is provided on the arc surface.

8. A thermal recovery casing head according to claim 7, characterized in that: A damping structure is provided between the sleeve (51) and the bolt.

9. The thermal recovery casing head according to claim 1, characterized in that: The included angle between the flange support (2) and the casing head body (1) is 40-45°, and the included angle between the mounting base plate (3) and the flange support (2) is 50-55°.

10. The thermal recovery casing head according to claim 1, characterized in that: The number of the arc-shaped plates (31) is five, and the five arc-shaped plates are evenly distributed around the circumference.

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