A carbon dioxide huff and puff wellhead seal

Abstract

The application discloses a carbon dioxide huff and puff well mouth sealing device and belongs to the technical field of oil production wells. The device comprises an upper double-flange sleeve and a lower double-flange sleeve which is screwed at the bottom of the upper double-flange sleeve, a socket cylinder sleeve is fixed to the inner wall of the lower double-flange sleeve, the upper end of the socket cylinder sleeve is inserted into the bottom of the upper double-flange sleeve, and the bottom of the socket cylinder sleeve extends to the outside of the lower double-flange sleeve. The carbon dioxide huff and puff well mouth sealing device is characterized in that multiple sealing structures are cooperated to strictly block carbon dioxide leakage, reduce resource waste and environmental influence, have good stability, the double-flange sleeve and the lock bolt and the angle plate are designed to resist high pressure and high temperature, the working condition is complex and stable, installation and maintenance are convenient, the positioning rod and the hole help accurate installation, the grease check valve is convenient for lubrication, flow control is accurate, the water injection pipe stop valve adjusts the gas volume as required, production is optimized to improve the recovery rate, operation efficiency is improved, cost is reduced, and the device is environment-friendly.

Description

Technical Field

[0001] This application relates to the field of oil well technology, and more specifically, to a carbon dioxide injection wellhead sealing device. Background Technology

[0002] In oil extraction, carbon dioxide flooding is widely used as an effective method to enhance oil recovery. However, existing carbon dioxide injection wellhead sealing devices often fail to achieve good sealing effects, leading to easy carbon dioxide leakage. This not only wastes resources but also has adverse effects on the surrounding environment. In some complex operating conditions, such as high pressure, high temperature, and frequent start-up and shutdown operations, the installation and maintenance are also relatively complex, requiring a lot of time and manpower. Replacing sealing components is difficult, and once damaged, they cannot be repaired or replaced in a timely and effective manner, affecting the normal operation of the entire production process. In view of this, we propose a carbon dioxide injection wellhead sealing device. Utility Model Content

[0003] 1. Technical problems to be solved

[0004] The purpose of this application is to provide a carbon dioxide injection wellhead sealing device that solves the technical problems mentioned in the background art. This carbon dioxide injection wellhead sealing device achieves the following: through the synergistic effect of multiple sealing structures, it effectively blocks carbon dioxide leakage, reduces resource waste and environmental impact, has excellent stability, and features a double flange sleeve, locking bolt, and angle plate design to resist high pressure and high temperature, ensuring stability even under complex working conditions. It is also convenient to install and maintain, with positioning rods and holes for precise installation, a grease check valve for easy lubrication, precise flow control, and a water injection pipe shut-off valve to adjust the gas volume as needed. This optimizes production, improves recovery rate, enhances operational efficiency, reduces costs, and is environmentally friendly.

[0005] 2. Technical Solution

[0006] This application provides a carbon dioxide injection wellhead sealing device, comprising: an upper double flange sleeve and a lower double flange sleeve threadedly connected to the bottom of the upper double flange sleeve. A socket cylinder sleeve is fixed to the inner wall of the lower double flange sleeve. The upper end of the socket cylinder sleeve is inserted into the bottom of the upper double flange sleeve, and the bottom of the socket cylinder sleeve extends to the outside of the lower double flange sleeve. A sealing column is positioned and installed inside the flange at the upper part of the upper double flange sleeve. A threaded sleeve is fixed to the bottom of the sealing column. A threaded rod is movably installed on the sealing column. A sealing plug is threaded onto the threaded sleeve. The bottom end of the threaded rod is fixedly connected to the sealing plug. The sealing plug is sealed and inserted into the upper end of the socket cylinder sleeve. A carbon dioxide injection pipe is fixedly connected to the upper double flange sleeve.

[0007] By adopting the above technical solution, a connection method that is both robust and easy to install and disassemble is provided through the threaded connection of the upper and lower double flange sleeves. A socket cylinder sleeve is fixedly installed inside the lower double flange sleeve. The upper end of the socket cylinder sleeve extends into the upper double flange sleeve, and the bottom extends to the outside of the lower double flange sleeve. The bottom of the socket cylinder sleeve is inserted and connected to the wellhead, and is fixed to the wellhead with bolts using the lower double flange sleeve. The sealing column is positioned and installed inside the upper flange of the upper double flange sleeve, and the bottom of the sealing column is fixedly connected to the threaded sleeve. The operator can flexibly adjust the position of the sealing head according to the actual situation by rotating the threaded rod, thereby realizing different states of the wellhead. The sealing plug-in connection between the sealing head and the upper end of the socket cylinder sleeve is the core link to ensure the sealing effect. This connection method can effectively prevent carbon dioxide from leaking along the gap. The carbon dioxide injection pipe is fixedly connected to the upper double flange sleeve, ensuring that carbon dioxide can be stably delivered to the designated location.

[0008] Optionally, the flange at the lower part of the upper double flange sleeve and the flange at the upper end of the lower double flange sleeve are threaded together with multiple locking bolts, and the lower double flange sleeve is welded with multiple angle plates along its circumference.

[0009] By adopting the above technical solution, multiple bolts are used to tightly connect the flange at the lower end of the upper double flange sleeve and the flange at the upper end of the lower double flange sleeve through threaded fixing, which enhances the connection strength and stability between the two. When subjected to large external forces, it can effectively prevent relative displacement between the upper and lower double flange sleeves, ensuring the structural integrity of the entire device. The multiple corner plates welded along the circumference of the lower double flange sleeve act as reinforcing ribs, significantly improving the bending and torsional resistance of the lower double flange sleeve itself, enabling it to better withstand loads from different directions, and further improving the reliability of the device under complex working conditions.

[0010] Optionally, the flange at the upper part of the upper double flange sleeve is threaded with multiple positioning rods along the circumference, and the sealing column is provided with positioning holes at the corresponding positioning rods along the circumference.

[0011] By adopting the above technical solution, multiple positioning rods are installed along the circumferential thread on the upper flange of the upper double flange sleeve. These positioning rods are evenly distributed, providing an accurate positioning reference for the sealing column, preventing the sealing column from shifting when subjected to vibration or other disturbances, ensuring that the sealing column always remains in the correct working position, thereby ensuring the normal operation of the entire sealing system.

[0012] Optionally, the sealing head includes a stud and a piston rod, which are fixedly connected. The stud is threaded into the sleeve, and multiple sealing rings are installed on the outer sleeve of the piston rod. The piston rod is installed in a sealing insertion into the upper end of the socket cylinder liner.

[0013] By adopting the above technical solution, the sealing head is composed of a stud and a piston rod. Because the stud is threaded into the sleeve, the lifting and lowering operation of the sealing head is more stable and precise, and the axial position of the sealing head can be adjusted as needed. The multiple sealing rings on the outer sleeve of the piston rod are made of wear-resistant and corrosion-resistant materials, which can form multiple sealing lines between the piston rod and the socket cylinder liner, effectively preventing carbon dioxide leakage. The piston rod is installed in a sealed plug-in manner inside the upper end of the socket cylinder liner, ensuring the sealing performance between the two, and maintaining a reliable sealing effect even under high pressure environment.

[0014] Optionally, a shut-off valve is installed on the carbon dioxide injection pipe.

[0015] By adopting the above technical solution, the shut-off valve can conveniently control the flow rate of carbon dioxide or even completely cut off the supply of carbon dioxide. During the production process, operators can adjust the opening of the shut-off valve to achieve precise flow control according to different production process requirements, such as changes in parameters like gas injection rate and gas injection volume.

[0016] Optionally, the socket cylinder sleeve is provided with two grease grooves inside the upper double flange sleeve, and a grease check valve is threadedly installed at each grease groove on the upper double flange sleeve.

[0017] By adopting the above technical solution, the socket cylinder liner is equipped with two grease grooves to store lubricating grease and provide lubrication for the piston rod. The grease check valve is installed on the upper double flange sleeve at the position corresponding to the grease groove, which can ensure that the lubricating grease can only flow in one direction, that is, it is added to the grease groove from the outside and will not flow back out. This can ensure that the lubricating grease is always present in the parts that need lubrication, reduce the frictional resistance between moving parts, reduce the degree of wear, and extend the service life of the device.

[0018] 3. Beneficial effects

[0019] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0020] 1. This device, through the synergistic effect of multiple sealing structures, such as the sealed plug head and the socket cylinder liner, and multiple sealing rings on the piston rod, can effectively prevent carbon dioxide leakage, greatly improve the sealing reliability of the wellhead, and reduce resource waste and environmental pollution.

[0021] 2. The double flange sleeve structure and bolt fixing method enable the device to maintain stable operation under harsh conditions such as high pressure and high temperature, and it is not easily affected by external factors to cause displacement or damage. In addition, the welding of the corner plate enhances the structural strength of the lower double flange sleeve, further improving the stability of the entire device. The connection method between the components is simple and reasonable, and easy to disassemble and assemble.

[0022] 3. The presence of the grease check valve makes adding lubricating grease more convenient, facilitates the plug head and socket cylinder liner connection, and reduces maintenance difficulty and cost;

[0023] 4. The shut-off valve on the carbon dioxide injection pipe can flexibly control the amount of carbon dioxide injected according to actual needs, meet the process requirements of different production stages, help optimize the production process, and improve the crude oil recovery rate. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of a carbon dioxide injection wellhead sealing device disclosed in a preferred embodiment of this application;

[0025] Figure 2 This is a partially exploded structural diagram of a carbon dioxide injection wellhead sealing device disclosed in a preferred embodiment of this application;

[0026] Figure 3 A preferred embodiment of this application discloses a carbon dioxide huff and puff wellhead sealing device. Figure 2 Enlarged structural diagram at point A in the middle;

[0027] Figure 4 A preferred embodiment of this application discloses a carbon dioxide huff and puff wellhead sealing device. Figure 2 Enlarged structural diagram at point B;

[0028] The following are the labels in the diagram: 1. Upper double flange sleeve; 11. Positioning rod; 12. Locking bolt; 2. Sealing post; 21. Threaded sleeve; 22. Positioning hole; 3. Threaded rod; 4. Sealing plug; 41. Threaded stud; 42. Piston post; 421. Sealing ring; 5. Carbon dioxide injection pipe; 51. Gate valve; 6. Lower double flange sleeve; 61. Angle plate; 7. Socket cylinder liner; 71. Grease groove; 8. Grease check valve. Detailed Implementation

[0029] The present application will be further described in detail below with reference to the accompanying drawings.

[0030] Reference Figures 1 to 4This application provides a carbon dioxide injection wellhead sealing device, comprising: an upper double flange sleeve 1 and a lower double flange sleeve 6 threadedly connected to the bottom of the upper double flange sleeve 1. A socket cylinder sleeve 7 is fixed to the inner wall of the lower double flange sleeve 6, with its upper end inserted into the bottom of the upper double flange sleeve 1 and its bottom extending to the outside of the lower double flange sleeve 6. A sealing post 2 is positioned and installed inside the flange at the upper part of the upper double flange sleeve 1, with a threaded sleeve 21 fixed to the bottom of the sealing post 2. A threaded rod 3 is movably installed on the sealing post 2, and a sealing plug 4 is threaded onto the threaded sleeve 21. The bottom end of the threaded rod 3 is fixedly connected to the sealing plug 4, and the sealing plug 4 is sealed and inserted into the upper end of the socket cylinder sleeve 7. A carbon dioxide injection pipe 5 is fixedly connected to the upper double flange sleeve 1. The threaded connection between the upper double flange sleeve 1 and the lower double flange sleeve 6 provides a method that is both robust and easy to install. The connection method for disassembly involves a socket cylinder sleeve 7 fixedly installed inside the lower double flange sleeve 6. The upper end of the socket cylinder sleeve 7 extends into the upper double flange sleeve 1, and the bottom extends to the outside of the lower double flange sleeve 6. The bottom of the socket cylinder sleeve 7 is connected to the wellhead by insertion and is fixed to the wellhead by bolts using the lower double flange sleeve 6. The sealing column 2 is positioned and installed inside the upper flange of the upper double flange sleeve 1. The bottom of the sealing column 2 is fixedly connected to the threaded sleeve 21. The operator can flexibly adjust the position of the sealing head 4 according to the actual situation by rotating the threaded rod 3, thereby realizing different states of the wellhead. The sealing insertion and connection between the sealing head 4 and the upper end of the socket cylinder sleeve 7 is the core link to ensure the sealing effect. This connection method can effectively prevent carbon dioxide from leaking along the gap. The carbon dioxide injection pipe 5 is fixedly connected to the upper double flange sleeve 1, ensuring that carbon dioxide can be stably delivered to the designated location.

[0031] Reference Figure 1 and Figure 2 Multiple locking bolts 12 are threadedly fixed between the lower flange of the upper double flange sleeve 1 and the upper flange of the lower double flange sleeve 6. Multiple angle plates 61 are welded around the circumference of the lower double flange sleeve 6. The multiple locking bolts 12 are threadedly fixed to tightly connect the lower flange of the upper double flange sleeve 1 and the upper flange of the lower double flange sleeve 6, which enhances the connection strength and stability between the two. When subjected to large external forces, it can effectively prevent relative displacement between the upper double flange sleeve 1 and the lower double flange sleeve 6, ensuring the structural integrity of the entire device. The multiple angle plates 61 welded around the circumference of the lower double flange sleeve 6 act as reinforcing ribs, significantly improving the bending and torsional resistance of the lower double flange sleeve 6 itself, enabling it to better withstand loads from different directions, and further improving the reliability of the device under complex working conditions.

[0032] Reference Figure 1 and Figure 2Multiple positioning rods 11 are installed along the circumferential threads on the flange of the upper double flange sleeve 1. Positioning holes 22 are opened at the corresponding positioning rods 11 along the circumference of the sealing column 2. The multiple positioning rods 11 installed along the circumferential threads on the upper flange of the upper double flange sleeve 1 are evenly distributed, providing an accurate positioning reference for the sealing column 2, preventing the sealing column 2 from shifting when subjected to vibration or other disturbances, ensuring that the sealing column 2 always remains in the correct working position, thereby ensuring the normal operation of the entire sealing system.

[0033] Reference Figure 2 and Figure 3 The sealing head 4 includes a stud 41 and a piston rod 42, which are fixedly connected. The stud 41 is threaded into the sleeve 21. Multiple sealing rings 421 are installed on the outer side of the piston rod 42. The piston rod 42 is installed in a sealed insert within the upper end of the socket cylinder liner 7. The sealing head 4 is composed of a stud 41 and a piston rod 42. Because the stud 41 is threaded into the sleeve 21, the lifting and lowering operation of the sealing head 4 is more stable and precise, and the axial position of the sealing head 4 can be adjusted as needed. The multiple sealing rings 421 on the outer side of the piston rod 42 are made of wear-resistant and corrosion-resistant materials, which can form multiple sealing lines between the piston rod 42 and the socket cylinder liner 7, effectively preventing carbon dioxide leakage. The piston rod 42 is installed in a sealed insert within the upper end of the socket cylinder liner 7, ensuring the sealing performance between the two, and maintaining a reliable sealing effect even under high pressure.

[0034] Reference Figure 1 and Figure 2 A shut-off valve 51 is installed on the carbon dioxide injection pipe 5. The shut-off valve 51 can easily control the flow rate of carbon dioxide or even completely cut off the supply of carbon dioxide. During the production process, the operator can adjust the opening of the shut-off valve 51 to achieve precise flow control according to different production process requirements, such as changes in parameters such as injection speed and injection volume.

[0035] Reference Figure 2 and Figure 4 The socket cylinder liner 7 is provided with two grease grooves 71 inside the upper double flange sleeve 1. A grease check valve 8 is threadedly installed at each grease groove 71 on the upper double flange sleeve 1. The socket cylinder liner 7 is used to store lubricating grease by setting two grease grooves 71 to provide lubrication for the piston column 42. The grease check valve 8 is installed at the position of the upper double flange sleeve 1 corresponding to the grease groove 71, which can ensure that the lubricating grease can only flow in one direction, that is, it is added to the grease groove 71 from the outside and will not flow back out. This can ensure that the lubricating grease is always present in the parts that need lubrication, reduce the frictional resistance between moving parts, reduce the degree of wear, and extend the service life of the device.

[0036] Working Principle: When carbon dioxide injection is required, this device is first installed at the wellhead. The upper double flange sleeve 1 and the lower double flange sleeve 6 are connected together by threads, and the connection is further reinforced by multiple locking bolts 12 to ensure the tightness of the connection. The upper end of the socket cylinder sleeve 7 inside the lower double flange sleeve 6 is inserted into the bottom of the upper double flange sleeve 1, and the bottom extends to the outside of the lower double flange sleeve 6 for insertion into the wellhead casing. When preparing to inject carbon dioxide, the shut-off valve 51 on the carbon dioxide injection pipe 5 is opened to allow carbon dioxide to enter the system smoothly. By operating the threaded rod 3, the sealing head 4 moves upward, and the piston column 42 of the sealing head 4 disengages from the upper end of the socket cylinder sleeve 7, thereby opening the wellhead casing. The wellhead passage allows for smooth carbon dioxide injection. After one injection cycle is completed, the threaded rod 3 is rotated in the reverse direction, causing the piston rod 42 of the sealing head 4 to be inserted into the upper end of the socket cylinder liner 7. The positioning rod 11 and positioning hole 22 ensure that the sealing rod 2 will not shift during operation, maintaining the stability of the device and achieving the sealing effect of the wellhead passage. Furthermore, the two grease grooves 71 in the socket cylinder liner 7 can be injected with grease through the corresponding grease check valve 8, reducing wear and facilitating the insertion and connection between the piston rod 42 and the socket cylinder liner 7, extending the service life of the device. The carbon dioxide injection can then be stopped. Throughout the process, all parts of the device work together to achieve effective sealing and control of the carbon dioxide injection wellhead.

Claims

1. A carbon dioxide huff and puff wellhead sealing device, characterized in that: Includes: an upper double flange sleeve (1) and a lower double flange sleeve (6) threaded to the bottom of the upper double flange sleeve (1). A socket cylinder sleeve (7) is fixed on the inner wall of the lower double flange sleeve (6). The upper end of the socket cylinder sleeve (7) is inserted into the bottom of the upper double flange sleeve (1). The bottom of the socket cylinder sleeve (7) extends to the outside of the lower double flange sleeve (6). A sealing column (2) is positioned and installed inside the flange at the upper part of the upper double flange sleeve (1). A threaded sleeve (21) is fixed at the bottom of the sealing column (2). A threaded rod (3) is movably installed on the sealing column (2). A sealing plug (4) is threaded onto the threaded sleeve (21). The bottom end of the threaded rod (3) is fixedly connected to the sealing plug (4). The sealing plug (4) is sealed and inserted into the upper end of the socket cylinder sleeve (7). A carbon dioxide water injection pipe (5) is fixedly connected to the upper double flange sleeve (1).

2. The carbon dioxide huff and puff wellhead sealing device according to claim 1, characterized in that: Multiple locking bolts (12) are threadedly fixed between the flange at the lower part of the upper double flange sleeve (1) and the flange at the upper end of the lower double flange sleeve (6). Multiple angle plates (61) are welded along the circumference of the lower double flange sleeve (6).

3. The carbon dioxide injection wellhead sealing device according to claim 1, characterized in that: The upper flange of the upper double flange sleeve (1) is threaded with multiple positioning rods (11) along the circumference, and the sealing column (2) is provided with positioning holes (22) at the corresponding positioning rods (11) along the circumference.

4. The carbon dioxide injection wellhead sealing device according to claim 1, characterized in that: The sealing head (4) includes a stud (41) and a piston rod (42), which are fixedly connected. The stud (41) is threaded into the sleeve (21), and the piston rod (42) is fitted with multiple sealing rings (421). The piston rod (42) is sealed and inserted into the upper end of the socket cylinder liner (7).

5. A carbon dioxide huff and puff wellhead sealing device according to claim 1, characterized in that: A shut-off valve (51) is installed on the carbon dioxide injection pipe (5).

6. The carbon dioxide injection wellhead sealing device according to claim 1, characterized in that: The socket cylinder sleeve (7) is provided with two grease grooves (71) inside the upper double flange sleeve (1), and a grease check valve (8) is threadedly installed at each grease groove (71) of the upper double flange sleeve (1).

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