Ultra-high-temperature and ultra-high-pressure self-activation wellhead sealing device

Abstract

The invention relates to the technical field of wellhead sealing devices, and discloses an ultra-high-temperature and ultra-high-pressure self-activation wellhead sealing device which comprises a four-way body, an oil pipe is arranged in the middle of the bottom end of the four-way body, a four-way cavity is formed in the four-way body, a hanger is arranged in the four-way cavity, and an oil pipe is arranged in the hanger. The four-way joint comprises a four-way joint body, a hanger is arranged on the four-way joint body, a threaded check ring is arranged on the outer side of the hanger in a sleeving mode, a sitting and hanging activation ring is arranged on the side edge of the threaded check ring, and a supporting ring is arranged on the top side of the sitting and hanging activation ring. The seat hanging activation ring, the supporting ring and the adjusting ring are arranged on the outer side of the hanger in a sleeving mode, so that the sealing device can be used between the hanger and the inner cavity of the four-way body, activation can be conducted through the dead weight of an underground tubular column, redundant steps are not needed, and the adjusting ring can control the compression amount of the sealing piece; and sealing elements are prevented from being damaged by overload while different pressure working conditions are adapted.

Description

Technical Field

[0001] The present invention relates to the technical field of wellhead sealing devices, and in particular to an ultra-high temperature and ultra-high pressure self-activating wellhead sealing device. Background Art

[0002] With the advancement and development of oil and gas field development technology, the area that can be explored and mined is becoming more and more vast. In some areas, oil and gas wells need to be drilled tens of thousands of meters. As the drilling depth increases, the pressure and temperature downhole will become higher and higher. This puts higher requirements on the sealing performance of the wellhead device. In the past, when the wellhead pressure was less than 10,000psi (70MPa) and the temperature was below 121°C, rubber seals were generally sufficient. When the pressure exceeded 10,000psi (70MPa), was below 20,000psi (140Mpa), and the temperature was below 180°C, general metal seals could also meet the requirements. However, when the pressure exceeded 20,000psi (140Mpa), the temperature exceeded 180°C, and even reached 650°C, and was in this situation for a long time, ordinary metal seals would encounter challenges in sealing continuity due to creep and other reasons. This structure is proposed to solve the sealing problem under ultra-high pressure of 30,000psi (210MPa) and ultra-high temperature of 650°C. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides an ultra-high temperature and ultra-high pressure self-activated wellhead sealing device, which solves the problem that in the past, when the wellhead pressure was less than 10,000psi (70MPa) and the temperature was below 121°C, rubber seals were generally sufficient. When the pressure exceeded 10,000psi (70MPa), was below 20,000psi (140Mpa), and the temperature was below 180°C, general metal seals could also meet the requirements. However, when the pressure exceeded 20,000psi (140Mpa), the temperature exceeded 180°C, and even reached 650°C, and was in such a condition for a long time, ordinary metal seals would encounter challenges in sealing continuity due to creep and other reasons.

[0004] The present invention provides the following technical solution: an ultra-high temperature and ultra-high pressure self-activated wellhead sealing device, comprising a spool body, a tubing is arranged in the middle of the bottom end of the spool body, a spool cavity is arranged in the spool body, and a hanger is arranged in the spool cavity;

[0005] The outer side of the hanger is sleeved with a threaded retaining ring, the side of the threaded retaining ring is provided with a sitting activation ring, the top side of the sitting activation ring is provided with a support ring, the support ring is sleeved on the outer side of the hanger, an outer graphite sealing ring is sleeved on the support ring, an adjustment ring is provided on the side of the outer graphite sealing ring, the outer side of the hanger is sleeved with an inner graphite sealing ring, a locking screw is provided between the threaded retaining ring and the hanger, and a four-way step is provided in the four-way cavity.

[0006] Preferred technical solution 1: A through hole is provided in the middle of the hanger, and the through hole is connected to the oil pipe.

[0007] Preferred technical solution 2: The bottom end of the threaded retaining ring is inclined.

[0008] Preferred technical solution three: the top of the support ring is convex.

[0009] Preferred technical solution four: the outer graphite sealing ring and the inner graphite sealing ring are arranged on both sides of the top protrusion of the support ring.

[0010] Preferred technical solution five: the adjustment ring is arranged between the outer graphite sealing ring and the inner graphite sealing ring.

[0011] This solution enables both sides of the adjustment ring to be limited by the outer graphite sealing ring and the inner graphite sealing ring.

[0012] Preferred technical solution six: the adjustment ring is fitted on the top of the support ring.

[0013] This solution can make the adjustment ring arranged on the top of the support ring more stable.

[0014] Preferred technical solution seven: The bottom end of the four-way step is inclined for easy installation.

[0015] This solution can make the four-way step more stably arranged in the four-way cavity.

[0016] Compared with the prior art, the present invention provides an ultra-high temperature and ultra-high pressure self-activated wellhead sealing device, which has the following beneficial effects: the present invention provides a sitting activation ring and a support ring on the four-way body, and an adjustment ring on the support ring, and the sitting activation ring, the support ring and the adjustment ring are sleeved on the outside of the hanger, so that the sealing device can be used between the hanger and the inner cavity of the four-way body, and can be activated by the deadweight of the downhole pipe string, without the need for extra steps, easy to install, and save drilling time. In addition, the sealing body of this structure is made of graphite material, which can meet the requirements of ultra-high temperature and ultra-high pressure, and can withstand ultra-high pressure 30000psi (210MPa) and below, ultra-high temperature 650℃ and below. The sealing structure of this structure can be automatically activated by the deadweight of the oil casing, and this structure has an adjustment ring to control the compression of the seal, adapting to different pressure conditions while preventing overload damage to the seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structural cross section of the present invention;

[0018] Figure 2 For the present invention Figure 1 A magnified view of the structure of the middle adjustment ring;

[0019] Figure 3 For the present invention Figure 1 Enlarged view of the structure of the inner graphite sealing ring.

[0020] In the figure: 1. four-way body; 2. oil pipe; 3. hanger; 4. threaded retaining ring; 5. sitting activation ring; 6. support ring; 7. outer graphite sealing ring; 8. adjustment ring; 9. inner graphite sealing ring; 10. locking screw; 11. four-way cavity; 12. four-way step. DETAILED DESCRIPTION

[0021] See also Figure 1-3 ,

[0022] Embodiment 1: An ultra-high temperature and ultra-high pressure self-activated wellhead sealing device, comprising a spool body 1, an oil pipe 2 is arranged in the middle of the bottom end of the spool body 1, a spool cavity 11 is arranged in the spool body 1, and a hanger 3 is arranged in the spool cavity 11;

[0023] A threaded retaining ring 4 is sleeved on the outer side of the hanger 3, a sitting activation ring 5 is arranged on the side of the threaded retaining ring 4, a support ring 6 is arranged on the top side of the sitting activation ring 5, the support ring 6 is sleeved on the outer side of the hanger 3, an outer graphite sealing ring 7 is sleeved on the support ring 6, an adjusting ring 8 is arranged on the side of the outer graphite sealing ring 7, an inner graphite sealing ring 9 is sleeved on the outer side of the hanger 3, a locking screw 10 is arranged between the threaded retaining ring 4 and the hanger 3, and a four-way step 12 is arranged in the four-way cavity 11.

[0024] A through hole is provided in the middle of the hanger 3 , and the through hole is connected with the oil pipe 2 .

[0025] The bottom end of the threaded retaining ring 4 is inclined.

[0026] The top of the support ring 6 is convex.

[0027] The outer graphite sealing ring 7 and the inner graphite sealing ring 9 are arranged on both sides of the top protrusion of the support ring 6 .

[0028] Embodiment 2: The difference between this embodiment and embodiment 1 is that, the adjustment ring 8 is arranged between the outer graphite sealing ring 7 and the inner graphite sealing ring 9.

[0029] The two sides of the adjustment ring 8 can be limited by the outer graphite sealing ring 7 and the inner graphite sealing ring 9.

[0030] Embodiment 3: The difference between this embodiment and embodiment 1 is that the adjustment ring 8 is fitted on the top of the support ring 6 .

[0031] This makes it more stable when the adjustment ring 8 is arranged on the top of the support ring 6 .

[0032] Embodiment 4: The difference between this embodiment and embodiment 1 is that the bottom end of the four-way step 12 is inclined for easy installation.

[0033] This makes the four-way step 12 more stably arranged in the four-way cavity 11 .

[0034] In this embodiment, as the drilling depth increases, the pressure and temperature downhole will become higher and higher. This places higher requirements on the sealing performance of the wellhead device. In the past, when the wellhead pressure was less than 10,000psi (70MPa) and the temperature was below 121°C, rubber seals were generally sufficient. When the pressure exceeds 10,000psi (70MPa), is below 20,000psi140Mpa, and the temperature is below 180°C, general metal seals can also meet the requirements. However, when the pressure exceeds 20,000psi140Mpa, the temperature exceeds 180°C, or even reaches 650°C, and is in this condition for a long time, ordinary metal seals will face challenges in sealing continuity due to creep and other reasons. This structure is proposed to solve the sealing problem under ultra-high pressure of 30,000psi210MPa and ultra-high temperature of 650°C.

[0035] In summary, in specific implementation, when the oil pipe 2 is lowered to the specified wellhead depth, the oil pipe 2 is connected to the bottom of the hanger 3. Then the hanger 3, the threaded retaining ring 4, the seat activation ring 5, the support ring 6, the outer graphite sealing ring 7, the adjustment ring 8, the inner graphite sealing ring 9, and the locking screw 10 are lowered into the four-way cavity 11 as a whole until the seat activation ring 5 contacts the four-way step 12.

[0036] The weight of the oil pipe 2 drives the hanger 3 to continue to press down, and the hanger 3 will compress the outer graphite seal ring 7, the adjusting ring 8, and the inner graphite seal ring 9. At the same time, the sitting activation ring 5 is restricted by the four-way step 12, and the support ring 6 is supported by the sitting activation ring 5. In this way, the outer graphite seal ring 7, the adjusting ring 8, and the inner graphite seal ring 9 cannot move downward and are squeezed from top to bottom.

[0037] Therefore, after the outer graphite sealing ring 7 and the inner graphite sealing ring 9 are compressed, they will expand in both the inner and outer directions of the diameter direction. At this time, the outer diameter of the outer graphite sealing ring 7 will be close to and squeeze the four-way cavity 11 to form a seal.

[0038] The inner diameter of the outer graphite seal ring 7 will be close to and squeeze the outer diameter of the support ring 6 to form a seal. The outer diameter of the inner graphite seal ring 9 will be close to and squeeze the inner diameter of the support ring 6 to form a seal. The inner diameter of the inner graphite seal ring 9 will be close to and squeeze the outer diameter of the hanger 3 to form a seal.

[0039] In this structure, the adjusting ring 8 is made of high temperature resistant rubber or plastic. According to the pressure working conditions, the adjusting ring 8 of different thicknesses can be replaced to adjust the compression degree of the inner graphite sealing ring 9 of the outer graphite sealing ring 7 so as to seal different pressures. At the same time, it can ensure that the inner graphite sealing ring 9 of the outer graphite sealing ring 7 will not be overloaded to cause sealing failure.

[0040] In this structure, the outer graphite sealing ring 7 and the inner graphite sealing ring 9 are made of graphite or graphite with other substances added to form a high-temperature resistant soft graphite material, which can withstand ultra-high pressure, ultra-high temperature, heavy load and other working conditions.

[0041] In this structure, the outer graphite sealing ring 7 and the inner graphite sealing ring 9 may be a plurality of stacked graphite rings, or a graphite ring may have metal wrapping sheets at the upper and lower ends, or graphite strips may be spirally wound in multiple layers.

[0042] In this structure, the sealing effect of the inner graphite sealing ring 9 of the outer graphite sealing ring 7 is automatically activated through the hanger 3 by utilizing the deadweight of the oil pipe 2 .

Claims

1. An ultra-high temperature and ultra-high pressure self-activated wellhead sealing device, characterized in that: It comprises a four-way body (1), an oil pipe (2) is arranged in the middle of the bottom end of the four-way body (1), a four-way cavity (11) is arranged in the four-way body (1), and a hanger (3) is arranged in the four-way cavity (11); The outer side of the hanger (3) is sleeved with a threaded retaining ring (4), the side of the threaded retaining ring (4) is provided with a sitting activation ring (5), the top side of the sitting activation ring (5) is provided with a support ring (6), the support ring (6) is sleeved on the outer side of the hanger (3), an outer graphite sealing ring (7) is sleeved on the support ring (6), the side of the outer graphite sealing ring (7) is provided with an adjustment ring (8), the outer side of the hanger (3) is sleeved with an inner graphite sealing ring (9), a locking screw (10) is provided between the threaded retaining ring (4) and the hanger (3), and a four-way step (12) is provided in the four-way cavity (11).

2. The ultra-high temperature and ultra-high pressure self-activated wellhead sealing device according to claim 1, characterized in that: A through hole is provided in the middle of the hanger (3), and the through hole is connected to the oil pipe (2).

3. The ultra-high temperature and ultra-high pressure self-activated wellhead sealing device according to claim 2, characterized in that: The bottom end of the threaded retaining ring (4) is inclined.

4. The ultra-high temperature and ultra-high pressure self-activated wellhead sealing device according to claim 3, characterized in that: The top end of the support ring (6) is convex.

5. The ultra-high temperature and ultra-high pressure self-activated wellhead sealing device according to claim 4, characterized in that: The outer graphite sealing ring (7) and the inner graphite sealing ring (9) are arranged on both sides of the top protrusion of the support ring (6).

6. The ultra-high temperature and ultra-high pressure self-activated wellhead sealing device according to claim 5, characterized in that: The adjustment ring (8) is arranged between the outer graphite sealing ring (7) and the inner graphite sealing ring (9).

7. The ultra-high temperature and ultra-high pressure self-activated wellhead sealing device according to claim 6, characterized in that: The adjustment ring (8) is fitted on the top end of the support ring (6).

8. The ultra-high temperature and ultra-high pressure self-activated wellhead sealing device according to claim 7, characterized in that: The bottom end of the four-way step (12) is inclined.

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