An ultra-high pressure metal mechanism capable of realizing two-stage sealing

Abstract

The utility model relates to high pressure sealing mechanism technical field, and disclose a kind of superhigh pressure metal mechanism of two-stage sealing can be realized, including oil pipe four-way component, the top side of oil pipe four-way component is provided with closure lid, suspension ware component is provided in the oil pipe four-way component, the middle part of oil pipe four-way component is symmetrically provided with several upper double-step inner locking ring, the bottom side of upper double-step inner locking ring is provided with double-step metal sealing assembly, the utility model is provided with upper double-step inner locking ring and lower double-step inner locking ring on oil pipe four-way component, so that the connection sealing between suspension ware component and oil pipe four-way component is more stable and compact, while meeting the strength of million-meter deep well test, also solve the problem that traditional outer locking ring is easy to accumulate sundries inside, meet the requirement of million-meter deep well design.

Description

Technical Field

[0001] This utility model relates to the field of high-pressure sealing mechanism technology, specifically an ultra-high-pressure metal mechanism that can achieve dual-stage sealing. Background Technology

[0002] With the gradual depletion of shallow and medium-depth oil and gas resources, deep and ultra-deep resources have become the main battleground for oil and gas exploration and development in my country. The successful drilling of wells reaching depths of 10,000 meters represents a significant breakthrough for my country in deep oil and gas resources, contributing to the optimization of its energy structure and reducing dependence on shallow and medium-depth resources. For example, the Tarim Oilfield's annual ultra-deep oil and gas production has reached 20.47 million tons, making it an important ultra-deep oil and gas production base in my country. Drilling these wells requires overcoming extreme conditions such as ultra-high temperatures and ultra-high pressures, which has driven advancements in oil extraction technology. The wellhead equipment, specifically the production tree, plays a crucial role as an important intermediate link in the production process.

[0003] As drilling depth continues to increase, the metal seal of the hanger, as the core component of the wellhead device and the most important barrier to ensure equipment safety, faces multiple impacts from high temperature, high pressure, and high sulfur corrosion. Traditional designs cannot meet the needs of deep wells at 10,000 meters in terms of both safety and functionality.

[0004] Currently, traditional metal sealing mechanisms, in pursuit of a high sealing effect, often use a low profile for the metal sealing material to achieve a permanent seal upon a single insertion. However, in actual drilling operations, situations may arise where the tubing gets stuck, requiring the tubing to be pulled back up. This necessitates a second pulling and re-insertion of the hanger. If the hanger's metal seal has already achieved a complete and reliable seal during the initial insertion, it becomes difficult to remove it from the wellbore using a top drive. Improper operation could even cause scratches or damage to the inner wall of the four-way valve. To address this issue, optimization in both materials and structure is necessary. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention provides an ultra-high pressure metal mechanism capable of achieving dual-stage sealing. This solves the problem of traditional metal sealing mechanisms, which, in pursuit of a high sealing effect, often set the metal sealing material at a low profile to achieve a permanent seal upon a single insertion. However, in actual drilling operations, situations may arise where the tubing gets stuck, requiring re-lifting of the tubing. This necessitates a second lifting and re-insertion of the hanger. If the hanger's metal seal has already achieved a complete and reliable seal during the initial insertion, it becomes difficult to remove it from the wellbore using a top drive. Improper operation may also cause scratches or even damage to the inner wall of the four-way connector. To address this issue, optimization of both materials and structure is required.

[0006] This utility model provides the following technical solution: an ultra-high pressure metal mechanism that can achieve dual-stage sealing, including an oil pipe four-way assembly, a closing cover is provided on the top side of the oil pipe four-way assembly, a hanger assembly is provided inside the oil pipe four-way assembly, a plurality of upper double-step inner locking rings are symmetrically arranged in the middle of the oil pipe four-way assembly, and a double-step metal sealing assembly is provided on the bottom side of the upper double-step inner locking rings. The double-step metal sealing assembly includes a lower double-step inner locking ring disposed on the side of the suspension assembly.

[0007] Preferred technical solution 1: The inner cavity of the oil pipe four-way assembly is provided with an installation groove, and the upper double-step inner locking ring is disposed in the installation groove.

[0008] Preferred technical solution 2: The top of the lower double-step inner locking ring is provided with an upper lip, and the bottom side of the lower double-step inner locking ring is provided with a lower lip.

[0009] Preferred technical solution 3: The inner cavity of the oil pipe four-way assembly is provided with two protruding steps, and the lower double-step inner locking ring is disposed between the two protruding steps.

[0010] Compared with the prior art, this utility model provides an ultra-high pressure metal mechanism that can achieve dual-stage sealing, which has the following beneficial effects: By setting an upper double-step inner locking ring and a lower double-step inner locking ring on the tubing four-way assembly, this utility model makes the connection and sealing between the suspension assembly and the tubing four-way assembly more stable and tight. While meeting the strength requirements of the 10,000-meter deep well test, it also solves the problem of easy accumulation of debris inside the traditional outer locking ring, thus meeting the design requirements of the 10,000-meter deep well.

[0011] In this solution, we also considered the specific working conditions on site. The sealing pressure of the lower metal seal is usually 20,000 PSI (140 MPa) or less, so a large sealing interference is not required. The upper metal seal needs to seal the extremely high pressure generated inside the tubing, which is usually 20,000 PSI (140 MPa) or more, so a large sealing interference is required. Considering different pressure ranges and on-site operational requirements, we designed the metal seal ring as a two-stage double-step seal. The lower metal seal is a self-weight seal of the hanger, which achieves the seal through the tubing hanger and the weight of the tubing (0-400T), and can seal the pressure below 20,000 PSI (140 MPa) at the lower part. The upper metal seal requires additional force (such as a set screw or locking ring manually or by machine) to achieve the seal on the basis of the self-weight seal.

[0012] In principle, the inner and outer diameters of the upper metal sealing lip are reduced by 0.2-0.3mm on each side compared to the inner and outer diameters of the lower metal sealing lip. This ensures that during installation, the lower seal with its lower interference fit can preferentially seal the annulus of the oil sleeve. At this point, the upper seal is not yet fully effective. If the oil pipe needs to be re-lifted, the oil pipe hanger can be easily removed because only the lower lip of the metal seal is sealed. After all procedures are completed and all potential problems are eliminated, the final step is to activate the upper seal of the metal seal, thus achieving complete installation.

[0013] Meanwhile, since the design of metal seals requires the lip to have a certain degree of plasticity to facilitate removal while satisfying the sealing effect, how to achieve a balance between plasticity and rigidity? We solve this problem by adding a certain proportion of trace rare metals to traditional stainless steel. Attached Figure Description

[0014] Figure 1 This is a schematic cross-sectional view of the structure of this utility model; Figure 2 For the present utility model Figure 1 Enlarged view of the structure of the double-step metal sealing assembly.

[0015] In the diagram: 1. Oil pipe four-way assembly; 2. Suspension assembly; 3. Upper double-step inner locking ring; 4. Double-step metal seal assembly; 5. Lower double-step inner locking ring. Detailed Implementation

[0016] Please see Figure 1-2 , Example 1: An ultra-high pressure metal mechanism that can achieve dual-stage sealing includes an oil pipe four-way assembly 1, a closing cover is provided on the top side of the oil pipe four-way assembly 1, a hanger assembly 2 is provided inside the oil pipe four-way assembly 1, a number of upper double-step inner locking rings 3 are symmetrically arranged in the middle of the oil pipe four-way assembly 1, and a double-step metal sealing assembly 4 is provided on the bottom side of the upper double-step inner locking rings 3. The double-step metal sealing assembly 4 includes a lower double-step inner locking ring 5 disposed on the side of the hanger assembly 2.

[0017] Example 2: The difference between this example and Example 1 is that the inner cavity of the oil pipe four-way assembly 1 is provided with an installation groove, and the upper double-step inner locking ring 3 is provided in the installation groove.

[0018] Example 3: The difference between this example and Example 1 is that the top of the lower double-step inner locking ring 5 is provided with an upper lip, and the bottom side of the lower double-step inner locking ring 5 is provided with a lower lip.

[0019] Example 4: The difference between this example and Example 1 is that the inner cavity of the oil pipe four-way assembly 1 is provided with two protruding steps, and the lower double-step inner locking ring 5 is provided between the two protruding steps.

[0020] In this embodiment, traditional metal sealing mechanisms, in pursuit of a sealing effect, often set the metal sealing material of the main body at a low level to achieve a permanent seal after a single insertion. However, in actual drilling operations, situations may arise where the tubing string gets stuck, requiring the tubing to be pulled back up. This necessitates a second pulling and re-insertion of the hanger. If the hanger's metal seal has already achieved a complete and reliable seal during the initial insertion, it becomes difficult to remove it from the wellbore using a top drive. Improper operation may even cause scratches or damage to the inner wall of the four-way valve. To address this issue, optimization in both materials and structure is necessary.

[0021] In summary, during implementation, users should first thoroughly clean the internal grooves of the upper double-step inner locking ring 3 and the lower double-step inner locking ring 5, and then use calipers to measure or visually inspect to ensure that the upper double-step inner locking ring 3 and the lower double-step inner locking ring 5 are not under stress and that their maximum outer diameter does not exceed the maximum outer diameter of the suspension assembly 2. Then, connect the suspension delivery tool and the top joint in sequence.

[0022] After vertically lifting the suspension assembly 2, inspect the outer end of the suspension assembly 2 for any defects that may affect the seal. Once confirmed to be correct, apply grease to the outer surface of the suspension assembly 2.

[0023] Install the double-step metal sealing assembly 4 on the hanger assembly 2 and apply grease again. Slowly lower the hanger assembly 2 through the drill table, ensuring that the hanger assembly 2 is centered during lowering to prevent damage to the sealing surface and locking ring.

[0024] First installation method - locking ring Once the suspension assembly 2 is in place, release all the suspension weight, activate the lower sealing lip of the seal, and drive the top drive to rotate the pick-and-place tool counterclockwise, causing the locking ring to open to the corresponding locking step inside the four-way valve. The starting torque of the locking ring is 13500 N.m. According to the instrument, when the torque of the top drive increases to 25000 N.m and cannot be raised further, it proves that it has been installed in place. At this time, it is necessary to lift 280T of weight upwards to confirm whether the locking ring is installed in place.

[0025] The second installation method - set screw Once the suspension assembly 2 is in place, release all the suspension weight, activate the lower sealing lip of the seal, and tighten the upper clamping ring of the suspension by tightening the tail of the set screw to a torque of 1800 N·m. Measure the exposed distance of the tail of the set screw to determine whether the locking ring is installed in place.

[0026] After installation, reverse the top drive, retrieve the delivery tools, and store them properly.

Claims

1. An ultra-high pressure metal mechanism capable of achieving dual-stage sealing, comprising an oil pipe four-way assembly (1), characterized in that: The top side of the oil pipe four-way assembly (1) is provided with a closing cover, the oil pipe four-way assembly (1) is provided with a hanger assembly (2), the middle part of the oil pipe four-way assembly (1) is symmetrically provided with several upper double-step inner locking rings (3), and the bottom side of the upper double-step inner locking rings (3) is provided with a double-step metal sealing assembly (4). The double-step metal sealing assembly (4) includes a lower double-step inner locking ring (5) disposed on the side of the hanger assembly (2).

2. The ultra-high pressure metal mechanism capable of achieving dual-stage sealing according to claim 1, characterized in that: The inner cavity of the oil pipe four-way assembly (1) is provided with an installation groove, and the upper double-step inner locking ring (3) is provided in the installation groove.

3. The ultra-high pressure metal mechanism capable of achieving dual-stage sealing according to claim 2, characterized in that: The top of the lower double-step inner locking ring (5) is provided with an upper lip, and the bottom side of the lower double-step inner locking ring (5) is provided with a lower lip.

4. The ultra-high pressure metal mechanism capable of achieving dual-stage sealing according to claim 3, characterized in that: The inner cavity of the oil pipe four-way assembly (1) is provided with two protruding steps, and the lower double-step inner locking ring (5) is provided between the two protruding steps.

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