Wellhead Christmas tree with anti-overflow thermal recovery casing head

Abstract

The invention relates to the technical field of oil exploitation, and provides a wellhead Christmas tree with an anti-overflow thermal recovery casing head, the wellhead Christmas tree comprises a Christmas tree body, a tubing head and the casing head, an empty groove I is formed in the inner wall of the casing head, a mounting ring is arranged in the empty groove I, and a disc spring group I is mounted between the mounting ring and the top of the empty groove I; an upper shell and a lower shell are arranged on the inner side of the mounting ring, the mounting ring and the upper shell are fixed through a first bolt, and the upper shell and the lower shell are arranged up and down and fixed through a second bolt; the mounting ring is driven by the thermally expanded sleeve to move upwards along the first empty groove, the first disc spring set is compressed, the radial displacement of movement is provided for the sleeve through the first disc spring set, and it can still be guaranteed that the sleeve is supported by the mounting ring; the casing pipe can move up and down through the mounting ring and the first disc spring set, thermal stress is released, and high stress caused by expansion limitation of the casing pipe is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum exploitation, in particular to a wellhead Christmas tree with an anti-overflow heat extraction casing head. Background Art

[0002] The Christmas tree is a wellhead device used to extract oil in self-flowing wells and machine-extracted wells. It is the main equipment for controlling and regulating oil and gas production at the top of the oil and gas well. It is mainly composed of three parts: the casing head, the tubing head, and the Christmas tree body. The tubing head is a device component that connects the uppermost casing head and the Christmas tree to suspend the tubing and seal the annular space between the tubing and the casing. During the thermal recovery process, high-temperature steam (usually exceeding 300°C) will be injected into the well, causing the temperature and pressure in the well to rise sharply. Under high temperature, the fluid volume expands and the pressure increases, which can easily cause wellhead overflow. High temperature may cause equipment material deformation or seal failure, increasing the risk of overflow.

[0003] In thermal recovery wells, high-temperature steam injection will cause components such as casing, hanger and casing head to expand due to heat. At the connection between the casing hanger and the casing head, geometric changes (such as steps and threads) will lead to uneven stress distribution, and the casing is fixed by the cement ring and the formation, and radial expansion is limited, which is mainly manifested in the axial position. Under high temperatures, these areas are more likely to produce stress concentration due to uneven thermal expansion. At the same time, periodic thermal cycles cause stress concentration areas to repeatedly bear high stress, eventually causing fatigue cracks; stress concentration may cause deformation or cracks on the sealing surface, destroying the sealing performance and causing steam leakage; in extreme cases, stress concentration may cause the casing hanger or casing head to break, resulting in serious accidents.

[0004] Therefore, the present invention provides a wellhead Christmas tree containing an anti-overflow heat production casing head. Summary of the invention

[0005] The present invention provides a wellhead Christmas tree with an anti-overflow casing head, which solves the problems existing in the background technology by arranging a freely movable installation structure.

[0006] The technical solution of the present invention is as follows: A wellhead Christmas tree with an anti-overflow casing head comprises: a Christmas tree body, a tubing head and a casing head connected from top to bottom by flanges, an empty groove one is opened on the inner wall of the casing head, and a mounting ring is arranged in the empty groove one, the mounting ring can slide in the empty groove one, and a disc spring group one is installed between the mounting ring and the top of the empty groove one, an upper shell and a lower shell are arranged on the inner side of the mounting ring, and the mounting ring is fixed to the upper shell by a bolt one, the upper shell and the lower shell are arranged up and down and fixed by a bolt two, and a sealing component is arranged at the bottom of the inner wall of the tubing head.

[0007] Preferably, four slips are arranged on the inner side of the upper shell body, a sealing ring 1 is sleeved on the outer side of the four slips, and a sealing ring 2 is fixedly connected to the top of the mounting ring.

[0008] Preferably, two upper shells and two lower shells are provided, one of the upper shells is provided with a card slot on its end surface, and the other upper shell is provided with a buckle matched with the card slot on its end surface.

[0009] Preferably, the sleeve head is provided with an inclined groove at the bottom of the empty groove one, the outer side of the mounting ring is provided with an annular groove one at the inclined groove, and a sealing ring three is arranged in the annular groove one, the sealing ring three is fitted with the inclined groove, the cross-section of the sealing ring three is U-shaped, and the U-shaped ends of the sealing ring three are fixedly connected in the annular groove one.

[0010] Preferably, a fixing groove 1 is provided on the inner wall of the mounting ring, and a heat conductive block 1 is fixedly connected through the fixing groove 1, the fixing groove 1 is communicated with an annular groove 1, and one end of the heat conductive block 1 is located in the annular groove 1, and the other end extends out of the mounting ring, a sliding groove 1 is provided on the end of the heat conductive block 1 extending out of the mounting ring, and a heat conductive block 2 is slidably connected through the sliding groove 1, and a spring 1 is installed between the heat conductive block 2 and the sliding groove 1.

[0011] Preferably, the annular groove 1 is provided with a circular ring 1 and a hollow circular ring 1 in the sealing ring 3, the two ends of the circular ring 1 are located in the hollow circular ring 1, and a spring 2 is installed between the side of the annular groove 1 close to the sliding groove 1 and the circular ring 1 and the hollow circular ring 1.

[0012] Preferably, a second ring groove and a third ring groove are respectively provided on the inner side and the outer side of the lower shell body, and a fourth sealing ring and a fifth sealing ring are respectively installed through the second ring groove and the third ring groove, and a slope is provided on the inner side of the installation ring at the lower shell body.

[0013] Preferably, the sealing assembly includes a second empty groove formed on the inner wall of the oil pipe head and a limiting ring arranged on the inner wall of the oil pipe head, a sealing ring is fixedly connected to the top of the second empty groove, the inner side of the sealing ring is an inclined surface, a sliding ring is arranged at the bottom of the sealing ring, a disc spring group 2 is installed between the sealing ring and the sliding ring, the limiting ring has an L-shaped cross-section, and the limiting ring is fixedly connected to the sliding ring, a fourth ring groove is formed on the outer side of the limiting ring, and a sixth sealing ring is installed through the fourth ring groove, the sixth sealing ring is in contact with the sealing ring, and a seventh sealing ring is installed at the bottom of one end of the limiting ring.

[0014] Preferably, the cross-section of the sealing ring six is ​​U-shaped, and the two ends of the U-shape of the sealing ring six are fixedly connected in the annular groove four, a fixing groove two is opened on the inner wall of the limiting ring, and a heat-conducting block three is fixedly connected through the fixing groove two, the fixing groove two is communicated with the annular groove four, and one end of the heat-conducting block three is located in the annular groove four, and a sliding groove two is opened at the other end, and a heat-conducting block four is slidably connected through the sliding groove two, and a spring three is installed between the heat-conducting block four and the sliding groove two.

[0015] Preferably, the annular groove four is provided with a circular ring two and a hollow circular ring two in the sealing ring six, the two ends of the circular ring two are located in the hollow circular ring two, and a spring four is installed between the side of the annular groove four close to the sliding groove two and the circular ring two and the hollow circular ring two.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention drives the mounting ring to move upward along the empty groove 1 through the heat-expanded sleeve and compresses the disc spring group 1, thereby providing the sleeve with radial displacement through the disc spring group 1, and still ensuring the support of the sleeve by the mounting ring.

[0017] 2. The present invention enables the sleeve to move up and down by installing a ring and a disc spring assembly, thereby releasing thermal stress and avoiding high stress caused by limited expansion of the sleeve; the stress generated by the disc spring assembly is dispersed, and by reducing the constraints on the sleeve, the stress generated by thermal expansion on the sleeve and the sleeve head is dispersed to a larger area, thereby avoiding stress concentration.

[0018] 3. The present invention realizes the sealing between the casing head and the mounting ring through the sealing ring three, realizes the sealing between the lower shell and the casing through the sealing ring four, and realizes the sealing between the lower shell and the mounting ring through the sealing ring five, so as to prevent the downhole liquid and gas outside the casing from overflowing, destroying the downhole pressure or causing pollution; and further protection is provided for preventing oil and gas from overflowing through the sealing rings one and two. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a wellhead Christmas tree of the present invention; Figure 2 It is a partial cross-sectional view of the tubing head and the casing head of the present invention; Figure 3 The present invention Figure 2 A partial enlarged view of middle A; Figure 4 The present invention Figure 2 Partial schematic diagram in; Figure 5 It is a three-dimensional diagram of the internal structure of the wellhead Christmas tree of the present invention; Figure 6 It is a three-dimensional diagram of the structure on the sleeve of the present invention; Figure 7It is a partial cross-sectional perspective view of the structure on the casing of the present invention; Figure 8 The present invention Figure 7 A partial enlarged view of middle C; Fig. 9 It is a connection stereogram of the sealing ring 3 of the present invention; Fig.10 This is a three-dimensional diagram of the connection of the sealing ring 6 of the present invention; Fig.11 The present invention Figure 4 A partial enlarged view of B.

[0020] In the figure: 1. Christmas tree body; 2. Tubing head; 3. Casing head; 31. Inclined groove; 41. Upper shell; 42. Lower shell; 43. Bolt 2; 44. Slip; 46. Sealing ring 1; 47. Sealing ring 2; 48. Ring groove 2; 49. Ring groove 3; 410. Sealing ring 4; 411. Sealing ring 5; 412. Slope; 413. Slot; 414. Buckle; 51. Empty groove 1; 52. Mounting ring; 53. Disc spring set 1; 54. Bolt 1; 55. Ring groove 1; 56. Sealing ring 3; 57. Fixed groove 1; 58. Heat transfer block 1; 59. Slide groove one; 510, heat transfer block two; 511, spring one; 512, ring one; 513, hollow ring one; 514, spring two; 6, sealing assembly; 61, hollow groove two; 62, limit ring; 63, sealing ring; 64, sliding ring; 65, disc spring assembly two; 66, ring groove four; 67, sealing ring six; 68, fixed groove two; 69, heat transfer block three; 610, heat transfer block four; 611, spring three; 612, ring two; 613, hollow ring two; 614, spring four; 615, sealing ring seven; 616, slide groove two; 7, sleeve. DETAILED DESCRIPTION

[0021] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0022] like Figure 1-Figure 11 As shown, the present invention provides a wellhead Christmas tree with an anti-overflow casing head, comprising: a Christmas tree body 1, a tubing head 2 and a casing head 3 connected from top to bottom by flanges, characterized in that: a hollow groove 51 is opened on the inner wall of the casing head 3, and a mounting ring 52 is arranged in the hollow groove 51, the mounting ring 52 can slide in the hollow groove 51, and a disc spring group 53 is installed between the mounting ring 52 and the top of the hollow groove 51, an upper shell 41 and a lower shell 42 are arranged on the inner side of the mounting ring, and the mounting ring 52 is fixed to the upper shell 41 by a bolt 54, the upper shell and the lower shell are arranged up and down and fixed by a bolt 43, and a sealing component 6 is arranged at the bottom of the inner wall of the tubing head 2.

[0023] like Figure 1-Figure 3 , Figure 5-Figure 7 As shown, four slips 44 are arranged on the inner side of the upper shell 41 , a sealing ring 1 46 is sleeved on the outer side of the four slips 44 , and a sealing ring 2 47 is fixedly connected to the top of the mounting ring 52 .

[0024] A second ring groove 48 and a third ring groove 49 are respectively formed on the inner side and the outer side of the lower shell 42 , and a fourth sealing ring 410 and a fifth sealing ring 411 are respectively installed through the second ring groove 48 and the third ring groove 49 . A slope 412 is provided on the inner side of the mounting ring 52 at the lower shell 42 .

[0025] There are two upper shells 41 and two lower shells 42 , one of which has a slot 413 on its end surface, and the other has a buckle 414 mounted on its end surface. The buckle 414 is made of elastic metal material.

[0026] When installing the casing 7 of the wellhead Christmas tree, the four slips 44 are first combined into one body, the outer cross-section of the slips 44 is two connected cones, and a sealing ring 46 is put on the conical connection of the outer sides of the four slips 44. The inner cross-section of the upper shell 41 is a cone that matches the cross-section of the slips 44. Then, the two upper shells 41 are put on the outer sides of the four slips 44 and merged, so that the buckle 414 on the end face of one of the upper shells 41 is inserted into the groove 413 on the end face of the other upper shell 41 to achieve a close fit, and the sealing between the slips 44 and the upper shell 41 is achieved by the sealing ring 46.

[0027] Then, insert the protrusion on the top of the lower shell 42 into the notch at the bottom of the upper shell 41, and then connect and fix the upper shell 41 to the lower shell 42 by the bolt 2 43, and then install the sealing ring 410 and the sealing ring 5 411 in the ring groove 2 48 and the ring groove 3 49 on the inner and outer sides of the lower shell 42, and then lower the lower shell 42 and the upper shell 41 to the top of the mounting ring 52 in the casing head 3, so that the sealing ring 2 47 on the top of the mounting ring 52 cooperates with the upper shell 41 to achieve sealing, and then fix the upper shell 41 on the mounting ring 52 by the bolt 1 54, and finally put the casing 7 into the casing head 3 from the center of the four slips 44.

[0028] The sealing ring five 411 protrudes out of the ring groove three 49 and has the same outer inclination as the slope 412 at the mounting ring 52. When the lower shell 42 is lowered to the slope 412 at the mounting ring 52, the sealing ring five 411 is squeezed with the slope 412, so that the sealing ring five 411 completely seals the lower shell 42 and the mounting ring 52. By setting the slope 412, the friction and deformation generated by the sealing ring when it is squeezed are reduced, so that it maintains a good sealing effect.

[0029] A latching tooth is provided on the inner side of the slips 44. When the sleeve 7 enters between the four slips 44, the four slips 44 are squeezed toward the upper shell 41 so that the latching tooth is stuck on the outer side of the sleeve 7 to fix the sleeve 7. The sealing ring four 410 protrudes out of the annular groove two 48. When the sleeve 7 is lowered, the sealing ring four 410 is squeezed so that the sealing ring four 410 completely seals the lower shell 42 and the sleeve 7.

[0030] The casing head 3 is provided with an inclined groove 31 at the bottom of the empty groove 51, and an annular groove 55 is provided on the outer side of the mounting ring 52 at the inclined groove 31, and a sealing ring 3 56 is arranged in the annular groove 55, the sealing ring 3 56 is fitted with the inclined groove 31, the cross-section of the sealing ring 3 56 is U-shaped, and the U-shaped ends of the sealing ring 3 56 are fixedly connected in the annular groove 55.

[0031] The casing head 3 and the mounting ring 52 are sealed by means of the sealing ring three 56, the lower shell 42 and the casing 7 are sealed by means of the sealing ring four 410, and the lower shell 42 and the mounting ring 52 are sealed by means of the sealing ring five 411, so as to prevent the downhole liquid and gas outside the casing 7 from overflowing, destroying the downhole pressure or causing pollution; and further protection is provided for preventing the oil and gas from overflowing by means of the sealing ring one 46 and the sealing ring two 47.

[0032] like Figure 2 , Figure 4 The sealing assembly 6 shown includes a second empty groove 61 opened on the inner wall of the oil pipe head 2 and a limiting ring 62 arranged on the inner wall of the oil pipe head 2. A sealing ring 63 is fixedly connected to the top of the second empty groove 61. The inner side of the sealing ring 63 is an inclined surface. A sliding ring 64 is arranged at the bottom of the sealing ring 63. A disc spring group 65 is installed between the sealing ring 63 and the sliding ring 64. The cross-section of the limiting ring 62 is L-shaped, and the limiting ring 62 is fixedly connected to the sliding ring 64. A fourth ring groove 66 is opened on the outer side of the limiting ring 62, and a sixth sealing ring 67 is installed through the fourth ring groove 66. The sixth sealing ring 67 is in contact with the sealing ring 63, and a seventh sealing ring 615 is installed at the bottom of one end of the limiting ring 62.

[0033] After the casing 7 is installed in the slip 44, the center of the oil pipe head 2 is aligned with the casing head 3 and lowered to the top of the casing head 3 and connected by a flange. During this period, one end of the limiting ring 62 moves to the top of the casing 7, so that the sealing ring 615 contacts and squeezes the top of the casing 7. Because the limiting ring 62 is fixedly connected to the sliding ring 64 and maintains an elastic connection with the sealing ring 63 through the disc spring group 65, the sealing ring 615 is tightly fitted with the casing 7 through the elastic force of the disc spring group 65 to achieve sealing; the disc spring group 65 has greater rigidity and can provide a greater limiting effect on the top of the casing 7, so that the casing 7 remains stable.

[0034] The sealing ring 615 is used to seal the tubing head 2 and the limit ring 62, and the sealing ring 615 is used to seal the limit ring 62 and the casing 7, thereby preventing the oil and gas in the annular space of the tubing and casing 7 from overflowing, destroying the downhole pressure or causing pollution.

[0035] like Figure 3 , Fig. 9 As shown, a fixing groove 57 is provided on the inner wall of the mounting ring 52, and a heat conducting block 58 is fixedly connected via the fixing groove 57. The fixing groove 57 is communicated with the annular groove 55, and one end of the heat conducting block 58 is located in the annular groove 55, and the other end extends out of the mounting ring 52. A slide groove 59 is provided on one end of the heat conducting block 58 extending out of the mounting ring 52, and a heat conducting block 2 510 is slidably connected via the slide groove 59, and a spring 511 is installed between the heat conducting block 2 510 and the slide groove 59.

[0036] The annular groove 1 55 is provided with a circular ring 1 512 and a hollow circular ring 1 513 in the sealing ring 3 56 , and both ends of the circular ring 1 512 are located in the hollow circular ring 1 513 , and a spring 2 514 is installed between the side of the annular groove 1 55 close to the sliding groove 1 59 and the circular ring 1 512 and the hollow circular ring 1 513 .

[0037] When thermal oil production is carried out, the casing 7 expands due to the heat. Since the casing 7 is fixed by the cement ring and the formation, the radial expansion is limited, so the casing 7 mainly exhibits axial displacement. When the casing 7 produces radial displacement, the casing 7 drives the mounting ring 52 to move upward along the slot 51 and compresses the disc spring group 53. The disc spring group 53 provides the casing 7 with radial displacement, and can still ensure the support of the mounting ring 52 for the casing 7.

[0038] At high temperatures, the connection area between the sleeve 7 and the sleeve head 3 is more likely to generate stress concentration due to uneven thermal expansion. The sleeve 7 can be displaced up and down by installing the ring 52 and the disc spring group 53 to release thermal stress and avoid high stress caused by limited expansion of the sleeve 7. The disc spring group 53 can disperse the generated stress and reduce the constraints on the sleeve 7, so that the stress generated by thermal expansion on the sleeve 7 and the sleeve head 3 is dispersed to a larger area to avoid stress concentration.

[0039] After the thermal expansion ends, the sleeve 7 is restored to its original position by the elastic force of the disc spring group 53; and during long-term injection and production suspension, the disc spring group 53 can absorb part of the deformation caused by the thermal expansion, further reducing the peak value, and the freely movable mounting ring 52 can avoid fatigue damage caused by temperature fluctuations.

[0040] During the movement of the mounting ring 52, the spring 2 514 in the annular groove 1 55 pushes the circular ring 1 512 and the hollow circular ring 1 513 to separate, thereby increasing the area of ​​the circular ring 1 512 and the hollow circular ring 1 513, and then pushing the sealing ring 3 56 to further expand, cooperate with the inclined groove 31, and maintain the seal between the mounting ring 52 and the sleeve head 3; by gradually expanding the area of ​​the sealing ring 3 56 and fitting with the inclined groove 31, the friction between the sealing ring 3 56 and the inclined groove 31 when the sealing ring 3 56 moves with the mounting ring 52 is reduced; at the same time, during the thermal expansion of the sleeve 7, the heat of the sleeve 7 is conducted to the fixed groove 1 57 and the annular groove 1 55 through the heat conducting block 2 510 and the heat conducting block 1 58, heating the gas in the annular groove 1 55 to make it expand, thereby further expanding the area of ​​the sealing ring 3 56, and at the same time, enabling the sealing ring 3 56 to fit more closely with the annular groove 1 55 and the inclined groove 31.

[0041] It should be noted that one end of the heat conductive block 2 510 close to the sleeve 7 is a slope. When the sleeve 7 is lowered, the sleeve 7 pushes the heat conductive block 2 510 into the slide groove 1 59 at one end of the heat conductive block 1 58 through the slope of the heat conductive block 2 510. The elastic force of the spring 1 511 pushes the heat conductive block 2 510 into close contact with the sleeve 7, thereby improving the heat conduction effect.

[0042] The cross-section of the sealing ring six 67 is U-shaped, and the two ends of the U-shape of the sealing ring six 67 are fixedly connected in the annular groove four 66. A fixing groove two 68 is provided on the inner wall of the limiting ring 62, and a heat-conducting block three 69 is fixedly connected through the fixing groove two 68. The fixing groove two 68 is communicated with the annular groove four 66, and one end of the heat-conducting block three 69 is located in the annular groove four 66, and a sliding groove two 616 is provided at the other end, and a heat-conducting block four 610 is slidably connected through the sliding groove two 616, and a spring three 611 is installed between the heat-conducting block four 610 and the sliding groove two 616.

[0043] like Figure 4 , Fig.10 , Fig.11 As shown, the ring groove four 66 is provided with a circular ring two 612 and a hollow circular ring two 613 in the sealing ring six 67, and both ends of the circular ring two 612 are located in the hollow circular ring two 613. A spring four 614 is installed between the side of the ring groove four 66 close to the sliding groove two 616 and the circular ring two 612 and the hollow circular ring two 613.

[0044] When the sleeve 7 moves upward, the limiting ring 62 can be driven to move upward to compensate for the displacement caused by the thermal expansion of the sleeve 7. At the same time, the sliding ring 64 fixedly connected to the limiting ring 62 compresses the disc spring group 65, and the disc spring group 65 reduces the impact and disperses the stress. During the movement of the limiting ring 62, the spring 3 611 in the ring groove 4 66 pushes the circular ring 612 and the hollow circular ring 613 to separate, thereby increasing the area of ​​the circular ring 612 and the hollow circular ring 613, and then pushes the sealing ring 67 to further expand, cooperate with the sealing ring 63, and keep the limiting ring 6 2 and the seal of the sleeve head 3; by gradually expanding the area of ​​the sealing ring 67 and fitting it with the sealing ring 63, the friction between the sealing ring 67 and the sealing ring 63 when it moves with the limit ring 62 is reduced; at the same time, during the thermal expansion of the sleeve 7, the heat of the sleeve 7 is conducted to the fixed groove 2 68 and the annular groove 4 66 through the heat conducting block 4 610 and the heat conducting block 3 69, heating the gas in the annular groove 4 66 to expand it, thereby further expanding the area of ​​the sealing ring 67, and at the same time enabling the sealing ring 67 to fit more closely with the annular groove 4 66 and the sealing ring 63.

[0045] It should be noted that the end of the heat conductive block four 610 close to the sleeve 7 is an inclined surface. When the oil pipe head 2 is lowered, the sleeve 7 pushes the heat conductive block four 610 into the slide groove two 616 at one end of the heat conductive block three 69 through the inclined surface of the heat conductive block four 610, and the elastic force of the spring three 611 pushes the heat conductive block three 69 to be in close contact with the sleeve 7, thereby improving the heat conduction effect.

[0046] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A wellhead Christmas tree with an anti-overflow heat recovery casing head, comprising: A Christmas tree body (1), a tubing head (2) and a casing head (3) connected from top to bottom by flanges, characterized in that: a hollow groove (51) is provided on the inner wall of the casing head (3), and a mounting ring (52) is provided in the hollow groove (51), the mounting ring (52) can slide in the hollow groove (51), and a disc spring assembly (53) is installed between the mounting ring (52) and the top of the hollow groove (51), an upper shell (41) and a lower shell (42) are provided on the inner side of the mounting ring, and the mounting ring (52) and the upper shell (41) are fixed by bolts (54), the upper shell and the lower shell are arranged up and down and fixed by bolts (43), and a sealing assembly (6) is provided at the bottom of the inner wall of the tubing head (2).

2. The wellhead Christmas tree with an anti-overflow casing head as claimed in claim 1, characterized in that: Four slips (44) are arranged on the inner side of the upper shell (41), and a sealing ring 1 (46) is sleeved on the outer side of the four slips (44). A sealing ring 2 (47) is fixedly connected to the top of the mounting ring (52).

3. The wellhead Christmas tree with an anti-overflow casing head according to claim 1, characterized in that: Two upper shells (41) and two lower shells (42) are provided, one of the upper shells (41) having a card slot (413) on its end surface, and the other upper shell (41) having a card buckle (414) matched with the card slot (413) installed on its end surface.

4. The wellhead Christmas tree with an anti-overflow casing head as claimed in claim 1, characterized in that: The sleeve head (3) is provided with an inclined groove (31) at the bottom of the empty groove (51), the outer side of the mounting ring (52) is provided with an annular groove (55) at the inclined groove (31), and a sealing ring (56) is provided in the annular groove (55), the sealing ring (56) is fitted with the inclined groove (31), the cross section of the sealing ring (56) is U-shaped, and the U-shaped ends of the sealing ring (56) are fixedly connected in the annular groove (55).

5. The wellhead Christmas tree with an anti-overflow casing head as claimed in claim 4, characterized in that: A fixing groove (57) is provided on the inner wall of the mounting ring (52), and a heat conducting block (58) is fixedly connected via the fixing groove (57); the fixing groove (57) is communicated with the annular groove (55), and one end of the heat conducting block (58) is located in the annular groove (55), and the other end extends out of the mounting ring (52); a sliding groove (59) is provided on the end of the heat conducting block (58) extending out of the mounting ring (52), and a heat conducting block (510) is slidably connected via the sliding groove (59); a spring (511) is installed between the heat conducting block (510) and the sliding groove (59).

6. The wellhead Christmas tree with an anti-overflow casing head as claimed in claim 5, characterized in that: The annular groove one (55) is provided with a circular ring one (512) and a hollow circular ring one (513) in the sealing ring three (56), and the two ends of the circular ring one (512) are located in the hollow circular ring one (513). A spring two (514) is installed between the side of the annular groove one (55) close to the sliding groove one (59) and the circular ring one (512) and the hollow circular ring one (513).

7. The wellhead Christmas tree with an anti-overflow casing head according to claim 1, characterized in that: The lower shell (42) is provided with a second ring groove (48) and a third ring groove (49) on the inner side and the outer side respectively, and a fourth sealing ring (410) and a fifth sealing ring (411) are installed through the second ring groove (48) and the third ring groove (49) respectively, and a slope (412) is provided on the inner side of the mounting ring (52) at the lower shell (42).

8. The wellhead Christmas tree with an anti-overflow casing head as claimed in claim 1, characterized in that: The sealing assembly (6) comprises a second hollow groove (61) formed on the inner wall of the tubing head (2) and a limiting ring (62) arranged on the inner wall of the tubing head (2); a sealing ring (63) is fixedly connected to the top of the second hollow groove (61); the inner side of the sealing ring (63) is an inclined surface; a sliding ring (64) is arranged at the bottom of the sealing ring (63); a second disc spring assembly (65) is installed between the sealing ring (63) and the sliding ring (64); the limiting ring (62) has an L-shaped cross section, and the limiting ring (62) is fixedly connected to the sliding ring (64); a fourth ring groove (66) is formed on the outer side of the limiting ring (62), and a sixth sealing ring (67) is installed through the fourth ring groove (66); the sixth sealing ring (67) is in contact with the sealing ring (63); and a seventh sealing ring (615) is installed at the bottom of one end of the limiting ring (62).

9. The wellhead Christmas tree with an anti-overflow casing head as claimed in claim 8, characterized in that: The cross-section of the sealing ring six (67) is U-shaped, and the two ends of the U-shape of the sealing ring six (67) are fixedly connected in the ring groove four (66). A fixing groove two (68) is provided on the inner wall of the limiting ring (62), and a heat conductive block three (69) is fixedly connected through the fixing groove two (68). The fixing groove two (68) is communicated with the ring groove four (66), and one end of the heat conductive block three (69) is located in the ring groove four (66), and a sliding groove two (616) is provided at the other end, and a heat conductive block four (610) is slidably connected through the sliding groove two (616), and a spring three (611) is installed between the heat conductive block four (610) and the sliding groove two (616).

10. The wellhead Christmas tree with an anti-overflow casing head according to claim 9, characterized in that: The annular groove four (66) is provided with a circular ring two (612) and a hollow circular ring two (613) in the sealing ring six (67), and the two ends of the circular ring two (612) are located in the hollow circular ring two (613). A spring four (614) is installed between the side of the annular groove four (66) close to the sliding groove two (616) and the circular ring two (612) and the hollow circular ring two (613).

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