CN-115653533-B - Compression type metal sealing structure for thermal production well

Abstract

The invention discloses a compression type metal sealing structure for a thermal production well, which comprises a central pipe, wherein the upper end of the central pipe is connected with a hydraulic cylinder mandrel, the lower part of the central pipe is connected with a pressure cap, a pressure transmission sleeve is arranged above the pressure cap, a pressure sleeve is arranged above the pressure sleeve, the inner side of the pressure sleeve is connected with the outer wall of the upper end of the central pipe through a lock ring, metal sealing assemblies are arranged between the pressure cap and the pressure transmission sleeve and between the pressure sleeve and the pressure sleeve, a storage cavity for thermal expansion fluid is arranged above the pressure sleeve, a push rod assembly is further arranged in the storage cavity, and the tail end of the push rod assembly is contacted with the upper end of the pressure sleeve. According to the invention, the sealing requirements of multiple steam huff and puff operations can be met through the two groups of metal sealing assemblies and the locking ring locking mechanism, the metal sealing assemblies cannot rub against the inner wall of a shaft in the well entering process, and the metal sealing function is realized when the thermal production well is used for injecting steam.

Inventors

• LUO JIANWEI
• WANG XINTAO
• WANG YAO
• BAO CHENYI
• JU SHAODONG
• LI QINGTAO
• LIU ZHILONG
• WANG MINGJIE

Assignees

• 中海油能源发展股份有限公司

Dates

Publication Date

20260512

Application Date

20221118

Claims (8)

1. 1. A compression type metal sealing structure for a thermal production well is characterized by comprising a central pipe (1), wherein the upper end of the central pipe (1) is connected with a hydraulic cylinder mandrel (10), the lower part of the central pipe (1) is connected with a pressure cap (3), a pressure transmission sleeve (7) is arranged above the pressure cap (3), a pressure sleeve (9) is arranged above the pressure transmission sleeve (7), the inner side of the pressure sleeve (9) is connected with the outer wall of the upper end of the central pipe (1) through a locking ring (8), metal sealing assemblies (19) are arranged between the pressure cap (3) and the pressure transmission sleeve (7) and between the pressure transmission sleeve (7) and the pressure sleeve (9), a storage cavity for a heat expansion fluid (15) is arranged above the pressure sleeve (9), a push rod assembly (20) is further arranged in the storage cavity, and the tail end of the push rod assembly (20) is in contact with the upper end of the pressure sleeve (9); the metal sealing assembly (19) comprises a bidirectional compression ring (6), a plurality of unidirectional compression rings (5) and a plurality of C-shaped metal rings (4), wherein the bidirectional compression ring (6) is positioned in the center of the metal sealing assembly (19), and the C-shaped metal rings (4) and the unidirectional compression rings (5) are alternately arranged on two sides of the bidirectional compression ring (6); the bidirectional compression ring (6) comprises a middle body and two side bumps, the unidirectional compression ring (5) comprises a 1/2 bidirectional compression ring (6) body and one side bump of the body, and the bump is inserted into a notch of the C-shaped metal ring (4).
2. 2. The compression type metal sealing structure for the thermal recovery well according to claim 1, wherein the inner wall of the upper end of the central tube (1) is connected with the outer wall of the lower end of the hydraulic cylinder mandrel (10) through threads.
3. 3. The compression type metal sealing structure for the thermal recovery well according to claim 1, wherein the pressure cap (3) is connected with the central tube (1) through threads and is fixed through a locking screw (2).
4. 4. The compression type metal sealing structure for the thermal production well according to claim 1, wherein the inner side and the outer side of the locking ring (8) are respectively connected with the pressing sleeve (9) and the central tube (1) through wedge threads with different tooth shapes.
5. 5. The compression type metal sealing structure for the thermal production well according to claim 1, wherein a cylinder sleeve (14) is sleeved outside the hydraulic cylinder mandrel (10), a boss is formed by extending the lower portion of the outer wall of the hydraulic cylinder mandrel (10) outwards, and a storage cavity for thermal expansion fluid (15) is formed by enclosing the outer wall of the hydraulic cylinder mandrel (10), the boss and the cylinder sleeve (14).
6. 6. The compression type metal sealing structure for the thermal recovery well according to claim 5, wherein the push rod assembly (20) comprises a push rod (12) and a metal corrugated pipe (13), one end of the metal corrugated pipe (13) is connected with the push rod (12), the other end of the metal corrugated pipe is connected with a boss of a hydraulic cylinder mandrel (10), and the lower end of the push rod (12) penetrates through the boss and is in contact with the upper end of the pressing sleeve (9).
7. 7. The compression type metal sealing structure for the thermal production well according to claim 5, wherein the lower end of the cylinder sleeve (14) is sealed with a boss of the hydraulic cylinder mandrel (10) through a metal O-ring (11), and the upper end of the cylinder sleeve (14) is sealed with the outer wall of the hydraulic cylinder mandrel (10) through a high-temperature resistant sealing ring (16).
8. 8. The compression type metal sealing structure for the thermal recovery well according to claim 5, wherein an injection hole is formed in the upper end of the cylinder sleeve (14), and a plug (17) is arranged in the injection hole.

Description

Compression type metal sealing structure for thermal production well Technical Field The invention relates to the technical field of oilfield development, in particular to a compression type metal sealing structure for a thermal production well. Background In the thick oil exploitation process, as the oil layer permeability has physical property difference, the situation that the vapor absorption is uneven easily occurs due to the adoption of general vapor injection, the utilization degree of part of well sections is lower, and the like, and the improvement of the crude oil recovery ratio is objectively influenced. The sectional steam injection can enable each layer section to absorb steam uniformly, increase the length of the effective well section, increase the heat utilization rate and improve the thermal recovery effect. In the process of sectional steam injection, a high-temperature and high-pressure resistant packing tool is needed to be put into a well, a thermosensitive high-temperature resistant packer and a metal insertion sealing tool are commonly used in various large oil fields at present, the thermosensitive high-temperature resistant packer gradually ages or loses elasticity along with the increase of steam throughput rounds, the effect is poorer and worse, and the sealing effect cannot be ensured due to friction between a sealing surface and a pipe wall caused by the lack of expansion compensation in the process of putting into the conventional metal insertion sealing tool. Disclosure of Invention The invention aims to solve the technical problems and provides a compression type metal sealing structure for a thermal production well. The structure adopts the compression type metal seal for the thickened oil well with segmented steam injection, can carry out multi-round steam huff and puff operation, and avoids seal failure caused by heat-sensitive high-temperature-resistant packer rubber cylinder aging, friction damage of a sealing surface in metal insertion seal and other reasons. The application is realized by adopting the following technical scheme. A compression type metal sealing structure for a thermal production well comprises a central pipe, wherein the upper end of the central pipe is connected with a hydraulic cylinder mandrel, the lower portion of the central pipe is connected with a pressure cap, a pressure transmission sleeve is arranged above the pressure cap, a pressure sleeve is arranged above the pressure transmission sleeve, the inner side of the pressure sleeve is connected with the outer wall of the upper end of the central pipe through a lock ring, metal sealing assemblies are arranged between the pressure cap and the pressure transmission sleeve and between the pressure transmission sleeve and the pressure sleeve, a storage cavity for thermal expansion fluid is arranged above the pressure sleeve, a push rod assembly is further arranged in the storage cavity, and the tail end of the push rod assembly is in contact with the upper end of the pressure sleeve. Further, the inner wall of the upper end of the central tube is connected with the outer wall of the lower end of the hydraulic cylinder mandrel through threads. Further, the pressing cap is connected with the central tube through threads and is fixed through a locking screw. Further, the metal sealing assembly comprises a bidirectional compression ring, a plurality of unidirectional compression rings and a plurality of C-shaped metal rings, wherein the bidirectional compression ring is positioned in the center of the metal sealing assembly, and the C-shaped metal rings and the unidirectional compression rings are alternately arranged on two sides of the bidirectional compression ring. Further, the bidirectional compression ring comprises a middle body and two side protruding blocks, the unidirectional compression ring comprises a 1/2 bidirectional compression ring body and one side protruding block of the body, and the protruding blocks are inserted into the gaps of the C-shaped metal ring. Further, the inner side and the outer side of the lock ring are respectively connected with the pressing sleeve and the central tube through wedge threads with different tooth shapes. Further, a cylinder sleeve is sleeved outside the hydraulic cylinder mandrel, the lower part of the outer wall of the hydraulic cylinder mandrel extends outwards to form a boss, and the outer wall of the hydraulic cylinder mandrel, the boss and the cylinder sleeve enclose a storage cavity for thermal expansion fluid. Further, the push rod assembly comprises a push rod and a metal corrugated pipe, one end of the metal corrugated pipe is connected with the push rod, the other end of the metal corrugated pipe is connected with a boss of a hydraulic cylinder mandrel, and the lower end of the push rod penetrates through the boss and is in contact with the upper end of the pressing sleeve. Furthermore, the lower end of the cylinder sleeve is sealed with a bo