High-pressure-resistant bushing double-plug cement head and processing and manufacturing method thereof

Abstract

The invention discloses a high-pressure-resistant casing pipe double-plug cement head and a processing and manufacturing method thereof, and relates to the technical field of cement heads, the high-pressure-resistant casing pipe double-plug cement head comprises a cement head body, a plurality of through holes are formed in the cement head body, grouting joints are connected in the through holes, a cavity is formed in the cement head body, and an upper rubber plug and a lower rubber plug are arranged in the cavity; the lower rubber plugs, the upper rubber plugs and the grouting joints are alternately arranged; a plug assembly is arranged on the top of the cement head body, and the bottom end of the cement head body is arranged on the sleeve. According to the high-pressure-resistant casing pipe double-plug cement head and the machining and manufacturing method thereof, through the double-rubber-plug design of the upper rubber plug and the lower rubber plug, the displacement efficiency of cement paste is improved, and the well cementation quality is improved; by arranging the head and the tail of the rubber plug into the circular truncated cone structures and arranging the step-shaped rings, the sealing capacity of the rubber plug is improved, the sealing performance of the cement head is enhanced, and the well cementation quality is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of cement heads, in particular to a high-pressure resistant casing double-plug cement head and a processing and manufacturing method thereof. Background Art

[0002] Cementing engineering is an indispensable and important link in the drilling operation. By injecting cement slurry into the well and displacing it into the annular space between the well wall and the casing at a predetermined depth, a strong bond is formed between the casing and the well wall, thereby isolating complex formations that are prone to collapse and leakage, ensuring that drilling is carried out smoothly to isolate oil, gas and water layers, establish oil and gas outflow channels, prevent cross-channeling between production layers, and ensure the safety of subsequent oil extraction projects.

[0003] The structural design of the rubber plug has an important impact on the sealing of the cement head. The traditional rubber plug structure is usually relatively simple, and mainly relies on the interference fit between the rubber plug and the inner wall of the cement head to achieve sealing. During the cementing operation, the rubber plug will be affected by the impact of the fluid and pressure fluctuations, which makes it difficult for the rubber plug to always maintain a good fit with the inner wall of the cement head, and it is easy to have a sealing gap, which leads to leakage. Summary of the invention

[0004] The purpose of the invention is to provide a high-pressure resistant casing double-plug cement head and a processing and manufacturing method thereof, so as to solve the problem of poor sealing performance of traditional cement head structures.

[0005] To achieve the above-mentioned purpose, the present invention provides a high-pressure resistant casing double-plug cement head, including a cement head body, a plurality of through holes are opened on the cement head body, a grouting joint is connected in the through holes, a cavity is opened inside the cement head body, an upper rubber plug and a lower rubber plug are arranged in the cavity, and the lower rubber plug and the upper rubber plug are alternately arranged with the grouting joint; a plug assembly is arranged on the top of the cement head body, and the bottom end of the cement head body is arranged on the casing.

[0006] Preferably, the plug assembly comprises a plug sleeved on the top of the cement head body, a lifting ring is provided on the top of the plug, and a limiting axis 1 is provided below the plug, and the limiting axis 1 extends into the cavity;

[0007] The plug is connected to the cement head body through a fixing piece.

[0008] Preferably, the cement head body is provided with two connecting openings, and the two connecting openings are respectively provided with a second limiting shaft and a third limiting shaft, the third limiting shaft is arranged below the lower rubber plug, and the second limiting shaft is arranged below the upper rubber plug;

[0009] The outer surfaces of the upper rubber plug and the lower rubber plug are both in contact with the inner wall of the cement head body.

[0010] Preferably, the upper rubber plug and the lower rubber plug both include a rubber plug head, a rubber plug body and a rubber plug tail, the rubber plug tail and the rubber plug head are both configured as truncated cone structures, and the rubber plug body is provided with a plurality of stepped rings.

[0011] Preferably, a triangular bayonet is symmetrically provided at the junction of the grouting joint and the cement head body, a clamp is fixedly provided in the triangular bayonet, and the clamp is fixedly connected to the outer wall of the cement head body.

[0012] Preferably, the clamp is configured as a special-shaped structure.

[0013] A method for processing and manufacturing a high-pressure resistant casing double-plug cement head comprises the following steps:

[0014] Step S1, parts processing: according to the drawing size, the various structures of the cement head are processed into workpieces with the drawing size to ensure that the workpiece size meets the design requirements;

[0015] Step S2, welding: first preheating the welding workpiece to 400-500° C., and then welding, using WE600 alloy steel welding rod for welding operation;

[0016] Step S3, post-welding insulation: after welding is completed according to welding requirements, the welding part is subjected to insulation treatment for 24 hours;

[0017] Step S4, weld joint flaw detection: perform flaw detection on the welded weld to check whether there are cracks, pores, and slag inclusion defects inside the weld;

[0018] Step S5, install and fix the limit shaft three, put the lower rubber plug into the cavity and place it above the limit shaft three, then install and fix the limit shaft two, put the upper rubber plug into the cavity and place it above the limit shaft two;

[0019] Step S6, overall pressure test: perform an overall pressure test on the double-plug cement head, maintain the pressure for 5 minutes, observe the pressure change, and ensure that the pressure drop does not exceed one percent of the total pressure; if the pressure drop is within the specified range, it means that the sealing and overall strength of the double-plug cement head meet the requirements; if the pressure drop exceeds the standard, find the cause and repair it until the pressure test is qualified again.

[0020] Therefore, the present invention adopts the above-mentioned high-pressure resistant casing double-plug cement head and its processing and manufacturing method, and improves the cement slurry displacement efficiency and the cementing quality through the double plug design of the upper plug and the lower plug; by setting the head and tail of the plug as a truncated cone structure and setting a plurality of stepped rings, the sealing ability of the plug is improved, the sealing of the cement head is enhanced, and the cementing quality is further improved.

[0021] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an embodiment of a high-pressure resistant casing double-plug cement head and a processing and manufacturing method thereof of the present invention;

[0023] Figure 2 It is a structural schematic diagram of an upper rubber plug or a lower rubber plug of a high-pressure resistant casing double-plug cement head and a processing and manufacturing method thereof of the present invention;

[0024] Figure numerals: 1. cement head body; 2. grouting joint; 3. cavity; 4. upper rubber plug; 5. lower rubber plug; 6. plug; 7. lifting ring; 8. limit axis one; 9. fixing piece; 10. limit axis two; 11. limit axis three; 12. rubber plug head; 13. rubber plug body; 14. rubber plug tail; 15. stepped ring; 16. clamp. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] Example

[0028] See also Figure 1-2 The present invention provides a double-plug cement head for high-pressure resistant casing. The present invention provides a double-plug cement head for high-pressure resistant casing, comprising a cement head body 1, a plurality of through holes are opened on the cement head body 1, a grouting joint 2 is connected in the through holes, a cavity 3 is opened inside the cement head body 1, an upper rubber plug 4 and a lower rubber plug 5 are arranged in the cavity 3, and the lower rubber plug 5 and the upper rubber plug 4 are alternately arranged with the grouting joint 2.

[0029] A plug assembly is provided at the top of the cement head body 1, and the bottom end of the cement head body 1 is provided on the sleeve. The plug assembly includes a plug 6 sleeved on the top of the cement head body 1, and a lifting ring 7 is provided at the top of the plug 6, and the lifting ring 7 is provided for lifting. A limit axis 8 is provided below the plug 6, and the limit axis 8 extends into the cavity 3. The plug 6 is connected to the cement head body 1 through a fixing member 9, and the fixing member 9 is a fixing bolt.

[0030] The cement head body 1 is provided with two connection ports, and the two connection ports are respectively penetrated with a second limiting shaft 10 and a third limiting shaft 11, the third limiting shaft 11 is arranged below the lower rubber plug 5, and the second limiting shaft 10 is arranged below the upper rubber plug 4. The second limiting shaft 10 and the third limiting shaft 11 play a limiting role on the upper rubber plug 4 and the lower rubber plug 5.

[0031] The outer surfaces of the upper rubber plug 4 and the lower rubber plug 5 are both in contact with the inner wall of the cement head body 1. The upper rubber plug 4 and the lower rubber plug 5 each include a rubber plug head 12, a rubber plug body 13 and a rubber plug tail 14. The rubber plug tail 14 and the rubber plug head 12 are both configured as a truncated cone structure, so that the rubber plug can easily enter the cement head body 1 and has better sealing ability. The rubber plug body 13 is provided with a plurality of stepped rings 15, and the provision of the plurality of stepped rings 15 improves the sealing ability of the rubber plug.

[0032] A triangular bayonet is symmetrically provided at the junction of the grouting joint 2 and the cement head body 1, and a clamp 16 is fixedly provided in the triangular bayonet. The clamp 16 is fixedly connected to the outer wall of the cement head body 1 by welding. The clamp 16 is set to a special-shaped structure to tightly fix the grouting joint 2 and the cement head body 1 together.

[0033] The manufacturing method of the high-pressure resistant casing double plug cement head comprises the following steps:

[0034] Step S1, parts processing: according to the drawing size, the various structures of the cement head are processed into workpieces with the drawing size, including the cement head body 1, the grouting joint 2, the plug assembly, and various limit shafts and clamps 16, and the workpiece size is ensured to meet the design requirements, so that the various structures of the cement head can meet their predetermined performance in cementing operations.

[0035] Step S2, welding: first preheat the cement head body 1, the grouting joint 2 and the clamp 16 to 400-500° C., and then weld them using WE600 alloy steel welding rods.

[0036] Step S3, post-welding insulation: After welding is completed according to welding requirements, the welding part is subjected to insulation treatment for 24 hours. Long-term insulation treatment helps to further eliminate the residual stress generated during the welding process and improve the fatigue resistance and service life of the overall structure of the cement head.

[0037] Step S4, weld joint flaw detection: perform flaw detection on the welded weld joint to check whether there are cracks, pores, and slag inclusion defects inside the weld joint. Avoid these defects from causing sealing failure or structural damage to the cement head during subsequent use, thereby ensuring the safety and reliability of the double-plug cement head.

[0038] Step S5, install and fix the limit axis three 11, put the lower rubber plug 5 into the cavity and place it above the limit axis three 11, then install and fix the limit axis two 10, put the upper rubber plug 4 into the cavity 3 and place it above the limit axis two 10.

[0039] Step S6, overall pressure test: perform an overall pressure test on the double-plug cement head, maintain the pressure for 5 minutes, observe the pressure change during this period, and require that the pressure drop does not exceed 1% of the total pressure; if the pressure drop is within the specified range, it means that the sealing and overall strength of the double-plug cement head meet the requirements; if the pressure drop exceeds the standard, find the cause and repair it until the pressure test is qualified again. By maintaining the pressure and observing the pressure change, the sealing performance of the double-plug cement head can be intuitively detected to ensure that the cement head will not leak during the cementing operation, and to ensure the normal transportation of cement slurry and the smooth progress of cementing operations.

[0040] Therefore, the present invention adopts the above-mentioned high-pressure resistant casing double-plug cement head and its processing and manufacturing method, and improves the cement slurry displacement efficiency and the cementing quality through the double plug design of the upper plug and the lower plug; by setting the head and tail of the plug as a truncated cone structure and setting a plurality of stepped rings, the sealing ability of the plug is improved, the sealing of the cement head is enhanced, and the cementing quality is further improved.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A high-pressure resistant casing double plug cement head, characterized in that: It includes a cement head body, a plurality of through holes are opened on the cement head body, grouting joints are connected in the through holes, a cavity is opened inside the cement head body, an upper rubber plug and a lower rubber plug are arranged in the cavity, and the lower rubber plug and the upper rubber plug are arranged alternately with the grouting joints; a plug assembly is arranged on the top of the cement head body, and the bottom end of the cement head body is arranged on the casing.

2. A high pressure resistant casing double plug cement head according to claim 1, characterized in that: The plug assembly includes a plug sleeved on the top of the cement head body, a hanging ring is provided on the top of the plug, and a limiting shaft 1 is provided below the plug, and the limiting shaft 1 extends into the cavity; The plug is connected to the cement head body through a fixing piece.

3. A high pressure resistant casing double plug cement head according to claim 2, characterized in that: The cement head body is provided with two connecting openings, and the two connecting openings are respectively penetrated with a second limiting shaft and a third limiting shaft, the third limiting shaft is arranged below the lower rubber plug, and the second limiting shaft is arranged below the upper rubber plug; The outer surfaces of the upper rubber plug and the lower rubber plug are both in contact with the inner wall of the cement head body.

4. A high pressure resistant casing double plug cement head according to claim 3, characterized in that: The upper rubber plug and the lower rubber plug both include a rubber plug head, a rubber plug body and a rubber plug tail. The rubber plug tail and the rubber plug head are both configured as truncated cone structures, and the rubber plug body is provided with a plurality of stepped rings.

5. A high pressure resistant casing double plug cement head according to claim 4, characterized in that: A triangular bayonet is symmetrically provided at the junction of the grouting joint and the cement head body, a clamp is fixedly clamped in the triangular bayonet, and the clamp is fixedly connected to the outer wall of the cement head body.

6. A high pressure resistant casing double plug cement head according to claim 5, characterized in that: The clamp is configured as a special-shaped structure.

7. A method for manufacturing a high-pressure casing double-plug cement head according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1, parts processing: according to the drawing size, the various structures of the cement head are processed into workpieces with the drawing size to ensure that the workpiece size meets the design requirements; Step S2, welding: first preheating the welding workpiece to 400-500° C., and then welding, using WE600 alloy steel welding rod for welding operation; Step S3, post-welding insulation: after welding is completed according to welding requirements, the welding part is subjected to insulation treatment for 24 hours; Step S4, weld joint flaw detection: perform flaw detection on the welded weld to check whether there are cracks, pores, and slag inclusion defects inside the weld; Step S5, install and fix the limit shaft three, put the lower rubber plug into the cavity and place it above the limit shaft three, then install and fix the limit shaft two, put the upper rubber plug into the cavity and place it above the limit shaft two; Step S6, overall pressure test: perform an overall pressure test on the double-plug cement head, maintain the pressure for 5 minutes, observe the pressure change, and ensure that the pressure drop does not exceed one percent of the total pressure; if the pressure drop is within the specified range, it means that the sealing and overall strength of the double-plug cement head meet the requirements; if the pressure drop exceeds the standard, find the cause and repair it until the pressure test is qualified again.

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