Locking mechanism applied to high-load working condition

Abstract

The utility model relates to the technical field of locking mechanisms, and discloses a locking mechanism applied to a high-load working condition, which comprises an oil pipe four-way assembly, two connecting flanges are symmetrically arranged at the upper end and the lower end of the oil pipe four-way assembly, and the connecting flanges are connected with the oil pipe four-way assembly through a plurality of connecting screws which are inserted in a penetrating manner. The double-step inner locking ring is arranged between the hanger body and the oil pipe four-way assembly, the double-step design is adopted in the double-step inner locking ring, and an outer locking ring is changed into the inner locking ring, so that the defects of a traditional locking ring can be effectively overcome; the inner locking ring is in a closed state in the whole process of installation and tripping-in, so that the risk that the hanger cannot be installed in place is reduced to the maximum extent, tightening and folding of the locking ring are facilitated, and the inner locking ring is suitable for being used in more complex working conditions.

Description

Technical Field

[0001] This utility model relates to the field of locking mechanism technology, specifically a locking mechanism applied to high-load conditions. 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 10,000-meter deep wells has enabled my country to achieve a major breakthrough in deep oil and gas resources, which helps to optimize the energy structure and reduce dependence on shallow and medium-depth resources. For example, the annual production of ultra-deep oil and gas in the Tarim Oilfield has reached 20.47 million tons, making it an important ultra-deep oil and gas production base in my country. The drilling of 10,000-meter deep wells requires overcoming extreme conditions such as ultra-high temperature and ultra-high pressure, which has promoted the advancement of oil extraction technology. The wellhead equipment, the production tree, plays a crucial role as an important intermediate link in production.

[0003] As drilling depth continues to increase, the locking mechanism 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, the traditional locking mechanism design of four-way valves still uses a top screw design. However, in ultra-high temperature and high pressure equipment such as 10,000-meter deep wells, due to comprehensive well control considerations, the top screw design increases the number of leakage points and reduces the rigidity of the connecting flange. Therefore, the design of the locking mechanism tends to use a locking ring design. The locking ring usually adopts a single-step external locking ring structure. The external locking ring is prone to the accumulation of rock cuttings and other foreign objects during drilling, which is not conducive to the tightening and closing of the locking ring. The single-step structure is mainly used in working conditions of 69 MPa (10,000 PSI) and below. In order to meet the complex working conditions of 10,000-meter deep wells, its original design needs to be modified to meet the application of complex working conditions. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a locking mechanism applicable to high-load conditions. It solves the problem that the traditional four-way locking mechanism still uses a top screw design. However, in ultra-high temperature and high pressure equipment such as deep wells, the top screw design increases leakage points and reduces the rigidity of the connecting flange due to comprehensive well control considerations. Therefore, the design of the locking mechanism tends to be a locking ring design. The locking ring usually adopts a single-step external locking ring structure. However, the external locking ring is prone to accumulating rock cuttings and other foreign objects during drilling, which is not conducive to the tightening and closing of the locking ring.

[0006] This utility model provides the following technical solution: a locking mechanism for high load conditions, including an oil pipe four-way assembly, two connecting flanges are symmetrically arranged at the upper and lower ends of the oil pipe four-way assembly, and the connecting flanges are connected to the oil pipe four-way assembly by a plurality of connecting screws inserted through them, and two fastening nuts are symmetrically sleeved at the upper and lower ends of the connecting screws.

[0007] The top of the middle part of the tubing four-way assembly is fitted with a hanger body, and a tubing head connecting pipe is provided below the hanger body. An inner locking ring mounting groove is provided between the hanger body and the inner wall of the tubing four-way assembly. A limiting top sleeve is fitted on the outer side of the hanger body. A double-step inner locking ring is provided on the outer side of the end of the limiting top sleeve. The side of the double-step inner locking ring abuts against the inner wall of the tubing four-way assembly. A bottom support ring is provided at the bottom end of the double-step inner locking ring.

[0008] Preferred technical solution 1: The bottom end of the suspension body is connected to the oil pipe head connecting pipe through a suspension assembly, and the suspension body and the suspension assembly are connected by a metal sealing assembly.

[0009] Preferred technical solution 2: The middle part of the oil pipe four-way assembly is provided with an installation channel, which is used for the installation of the hanger body and the oil pipe head connecting pipe.

[0010] Preferred technical solution 3: The outer side of the bottom end of the limiting top sleeve is inclined.

[0011] This solution enables the limiting top sleeve to more stably resist and limit the inner locking ring of the double-step mechanism.

[0012] Preferred technical solution four: The inner wall of the double-step inner locking ring is inclined and fits against the outer side of the limiting top sleeve.

[0013] This design enables the double-step inner locking ring to tightly seal the outer side of the suspension body under the combined action of the limiting top sleeve and the inner wall of the oil pipe four-way assembly.

[0014] Compared with the prior art, this utility model provides a locking mechanism for high-load conditions, which has the following advantages:

[0015] (1) This utility model has a double-step inner locking ring between the hanger body and the tubing four-way assembly. The double-step inner locking ring adopts a double-step design, changing the outer locking ring into an inner locking ring, which can effectively solve the drawbacks of traditional locking rings and improve its structural stability in deep wells. Secondly, the design of the inner locking ring requires the use of special delivery tools. After the hanger is installed in place, the top drive of the rotating drilling rig is used to achieve repeated release, thereby locking the hanger. In this process, since the structure of the inner locking ring is used, unlike the outer locking ring, the corresponding gap is prone to the accumulation of foreign objects. Since the inner locking ring is in a closed state throughout the installation and lowering process, foreign objects will not remain in the gap. This minimizes the risk of the hanger not being able to be installed in place and is more conducive to the tightening and closing of the locking ring, adapting to more complex working conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the external structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the internal structure of this utility model;

[0018] Figure 3 This is a schematic diagram of the internal cross-section of the structure of this utility model;

[0019] Figure 4 The structure of this utility model Figure 3 Enlarged view of the structure of the double-step inner locking ring.

[0020] In the diagram: 1. Tubing four-way assembly; 2. Connecting flange; 3. Connecting screw; 4. Fastening nut; 5. Hanger body; 6. Tubing head connecting pipe; 7. Inner locking ring mounting groove; 8. Limiting top sleeve; 9. Double-step inner locking ring; 10. Bottom support ring; 11. Hanger assembly; 12. Metal sealing assembly. Detailed Implementation

[0021] Please see Figure 1-4 ,

[0022] Example 1: A locking mechanism for high load conditions includes a four-way oil pipe assembly 1. Two connecting flanges 2 are symmetrically arranged at the upper and lower ends of the four-way oil pipe assembly 1. The connecting flanges 2 are connected to the four-way oil pipe assembly 1 by a number of through-inserted connecting screws 3. Two fastening nuts 4 are symmetrically sleeved at the upper and lower ends of the connecting screws 3.

[0023] A hanger body 5 is inserted into the top of the middle part of the tubing four-way assembly 1. A tubing head connecting pipe 6 is provided below the hanger body 5. An inner locking ring mounting groove 7 is provided between the hanger body 5 and the inner wall of the tubing four-way assembly 1. A limiting top sleeve 8 is fitted on the outer side of the hanger body 5. A double-step inner locking ring 9 is provided on the outer side of the end of the limiting top sleeve 8. The side of the double-step inner locking ring 9 abuts against the inner wall of the tubing four-way assembly 1. A bottom support ring 10 is provided at the bottom end of the double-step inner locking ring 9. The bottom end of the hanger body 5 is connected to the tubing head connecting pipe 6 through the provided hanger assembly 11. The hanger body 5 and the hanger assembly 11 are connected by a provided metal sealing assembly 12.

[0024] Example 2: The difference between this example and Example 1 is that the oil pipe four-way assembly 1 is provided with an installation channel in the middle, which is used for the installation of the hanger body 5 and the oil pipe head connecting pipe 6.

[0025] Example 3: The difference between this example and Example 1 is that the outer side of the bottom end of the limiting top sleeve 8 is inclined.

[0026] This makes the contact limit of the top sleeve 8 with the double-step inner locking ring 9 more stable.

[0027] Example 4: The difference between this example and Example 1 is that the inner wall of the double-step inner locking ring 9 is inclined and fits against the outer side of the limiting top sleeve 8.

[0028] This allows the double-step inner locking ring 9 to tightly seal the outside of the suspension body 5 under the combined action of the limiting top sleeve 8 and the inner wall of the oil pipe four-way assembly 1.

[0029] In this embodiment, the traditional four-way locking mechanism still uses a top screw design. However, in ultra-high temperature and high pressure equipment such as 10,000-meter deep wells, the top screw design increases leakage points and reduces the rigidity of the connecting flange due to comprehensive well control considerations. Therefore, the locking mechanism design tends to use a locking ring design. The locking ring usually adopts a single-step external locking ring structure. The external locking ring is prone to accumulating rock cuttings and other foreign objects during drilling, which is not conducive to the tightening and closing of the locking ring. The single-step structure is mainly used in working conditions of 69 MPa (10,000 PSI) and below. In order to meet the complex working conditions of 10,000-meter deep wells, its original design needs to be modified to meet the application of complex working conditions.

[0030] In summary, during implementation, the user first needs to thoroughly clean the groove inside the double-step inner locking ring 9, and then use calipers to measure or visually inspect to ensure that the double-step inner locking ring 9 is not under stress and that its maximum outer diameter does not exceed the maximum outer diameter of the hanger body 5. Then connect the hanger delivery tool and the top joint in sequence.

[0031] After vertically lifting the hanger body 5, inspect the outer end of the hanger body 5 for any defects that may affect the seal. Once confirmed to be correct, apply grease to the outer surface of the hanger body 5, install the seal on the hanger body 5, and apply grease again. Slowly lower the hanger body 5 through the drill table, ensuring that the hanger body 5 is centered in the oil pipe four-way assembly 1 to prevent damage to the sealing surface and the double-step inner locking ring 9.

[0032] Once the suspension body 5 is in place, the top drive is activated to rotate the pick-and-place tool counterclockwise, causing the double-step inner locking ring 9 to open to the corresponding locking step inside the four-way connector. The starting torque of the double-step inner locking ring 9 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 double-step inner locking ring 9 has been installed in place. After installation, the top drive is reversed to retrieve the pick-and-place tool and store it properly.

[0033] Compared to the traditional locking ring design with a single-step outer locking ring, which can only meet working conditions of 69 MPa (10000 PSI) and below, we changed its structure from a single-step to a double-step design and the outer locking ring to an inner locking ring. This change can effectively solve the shortcomings of the traditional locking ring and improve its structural stability in deep wells. First, changing from a single step to a double step increases its load-bearing strength by 100%. Based on the theoretical analysis of finite element software, the contact area of ​​the first bearing platform step is designed to be about 25% higher than that of the second step, allowing it to bear 75% of the total load. At the same time, the second bearing step serves as an auxiliary and emergency use, improving the torsional rigidity of the body while meeting the strength requirements.

[0034] Secondly, the design of the inner locking ring requires the use of a special delivery tool. After the hanger is installed in place, the top drive of the rotating drilling rig is used to repeatedly release it, thereby locking the hanger. During this process, because of the inner locking ring structure, unlike the outer locking ring where foreign objects are prone to accumulate in the corresponding gaps, the inner locking ring is in a closed state throughout the installation and lowering process, so foreign objects will not remain in the gaps, thus minimizing the risk of the hanger not being installed in place.

[0035] Furthermore, in order to meet the strength requirements while ensuring a certain degree of plasticity to achieve the desired expansion and contraction, we solve the problem of how to achieve a balance between plasticity and rigidity by adding a certain proportion of trace rare metals to traditional spring steel.

Claims

1. A locking mechanism for high-load conditions, comprising an oil pipe four-way assembly (1), characterized in that: The oil pipe four-way assembly (1) has two connecting flanges (2) symmetrically arranged at its upper and lower ends. The connecting flanges (2) are connected to the oil pipe four-way assembly (1) by several connecting screws (3) inserted through them. The upper and lower ends of the connecting screws (3) are symmetrically fitted with two fastening nuts (4). The top of the middle part of the tubing four-way assembly (1) is provided with a hanger body (5), and a tubing head connecting pipe (6) is provided below the hanger body (5). An inner locking ring mounting groove (7) is provided between the hanger body (5) and the inner wall of the tubing four-way assembly (1). A limiting top sleeve (8) is sleeved on the outside of the hanger body (5). A double-step inner locking ring (9) is provided on the outside of the end of the limiting top sleeve (8). The side of the double-step inner locking ring (9) abuts against the inner wall of the tubing four-way assembly (1). A bottom support ring (10) is provided at the bottom end of the double-step inner locking ring (9).

2. The locking mechanism for high-load conditions according to claim 1, characterized in that: The bottom end of the hanger body (5) is connected to the oil pipe head connecting pipe (6) through the hanger assembly (11), and the hanger body (5) and the hanger assembly (11) are connected by the metal sealing assembly (12).

3. A locking mechanism for high-load conditions according to claim 2, characterized in that: The oil pipe four-way assembly (1) has an installation channel in the middle, which is used for the installation of the hanger body (5) and the oil pipe head connecting pipe (6).

4. A locking mechanism for high-load conditions according to claim 3, characterized in that: The outer side of the bottom end of the limiting top sleeve (8) is inclined.

5. A locking mechanism for high-load conditions according to claim 4, characterized in that: The inner wall of the double-step inner locking ring (9) is inclined to fit against the outer side of the limiting top sleeve (8).

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