Mandrel type hanger of all-metal multi-stage and equidimension sealing structure

Abstract

The invention discloses a mandrel type hanger of an all-metal multi-stage and equidimension sealing structure. The mandrel type hanger of the all-metal multi-stage and equidimension sealing structurecomprises a mandrel, an upper flange, a cross, a lower flange, a spinning sleeve, a cone sealing ring, a sealing backing ring, a positioning ring, a suspension sleeve, a surface layer sleeve, a metalcompression ring, an X type sealing ring and a support backing ring. The mandrel is provided with a neck section, an upper stage section, a conical surface section, a lower stage section, a connectingthread section and a cone thread section from top to bottom, and the mandrel is axially arranged in the cross. A cone gap is formed between the conical surface of the cross and the conical surface section of the mandrel, the cone sealing ring is arranged in the cone gap, and the spinning sleeve is connected to the upper stage section of the mandrel in a threaded mode and presses the cone sealingring. The metal compression ring, the X type sealing ring and the support backing ring are arranged in an annular ladder slot on the lower portion of the cross. The mandrel type hanger of the all-metal multi-stage and equidimension sealing structure does not involve rubber sealing parts and is able to withstand various adverse environmental impacts, and service time is greatly improved and the overall sealing stability of a casing head is ensured.

Description

Technical field [0001] The invention relates to the technical field of drilling and production equipment for oil and gas wells, in particular to a mandrel hanger with an all-metal multi-stage and equal cone sealing structure. Background technique [0002] The slip hanger is used in the field, and the sealing structure is subject to compression load and temperature change for a long time, which makes the rubber parts easy to age. During the pressure test, the main seal failure often occurs. Therefore, the mandrel hanger is relatively reliable. Type hanger is used for tubing or casing suspension. Its suspension method and sealing principle are basically the same, and have basically the same sealing structure and sealing mechanism. However, the existing mandrel type hanger mostly uses metal seals and elastic rubber seals. This type of sealing structure occasionally leaks, and the metal seal is not good after installation. The pressure test is qualified because the elastic rubber sea...

AI Technical Summary

Problems solved by technology

[0002] Slip hangers are used on site, and the sealing structure is subjected to compressive loads and severe temperature changes for a long time, which makes the rubber parts easy to age. During the pressure test, the main seal failure often occurs, so the use of mandrel hangers is relatively reliable. Type hanger is used for tubing hanger or casing hanger. Its suspension method and sealing principle are basically the same, and it has basically the same sealing structure and sealing mechanism. However, the sealing structure of the existing mandrel hanger mostly adopts metal seal and elastic rubber seal. The mixed form of this kind of sealing structure occasionally leaks, and the metal seal is not good after installation. The pressure test is qualified because the elastic rubber seal works. After a long time, the rubber will age or be corroded by the corrosive medium, and the sealing will be lost. When the existing structure is installed It is impossible to judge whether the metal seal or the elastic rubber seal is in effect. During the installation of the hanging hanger on site, it is impossible to judge whether the metal seal is bruised. Therefore, there is a "blind sitting" situation on the sealing part. If the seal inspection fails after the seat is hung, The hanger and the casing must be lifted off the wellhead for inspection and replacement. If the cement returns to the wellhead and has solidified or the casing is too heavy, it will lead to the failure of the overall installation operation when it is difficult to lift up. The tubing hanger also has potential risks and seal failure. The consequence is more serious than that of the casing hanger, which may cause serious annular pressure, forced well killing and workover, resulting in huge economic losses and environmental safety

[0003] Through searching the related documents and patents of hangers at home and abroad, the structural form adopted by the slip hanger is easy to replace the hanger, but it is not easy to judge and test the existence of the seat seal. There is no way to avoid blind seats. The sealing structure of some hangers follows the traditional double O-ring and bimetallic sealing ring design, which has reliable sealing performance, but still needs to use rubber parts. Patent CN201510167051.8 is passed on the casing head body. The pressure test hole is used to test the reliability of the seal. In case of seal failure, the metal seal can be replaced with a disassembly tool. Since the seal part uses an O-ring as a functional ring, there must be defects of aging and failure; making it more suitable for complex wells It is used in high temperature and high pressure oil and gas wells. Although the sealing reliability is guaranteed in the short term, there are still defects of rubber parts failure and aging in long-term operation; although the patent CN200920255438.9 solves the problem that the rubber seals of traditional hangers are easy to age and difficult to replace. , it is unavoidable to produce blind seats; patent CN201220739199.6 implements a combined sealing structure of metal seal + BT ring grease injection; all rubber seals are made of "highly saturated hydrogenated nitrile rubber" material; GE's metal seal patent uses In the form of tooth seal, the straight teeth are embedded in the inner surface of the expansion spring to realize the interference fit between the metal atoms to realize the metal seal, but the manufacturing and installation costs are high, the matching accuracy is high, and the structure is relatively complicated, which is not conducive to popularization

[0004] These existing patents and product sealing parts inevitably require the use of rubber seals, which are prone to aging of rubber parts. Under various harsh external environments, the life of rubber parts will be greatly affected, greatly reducing the reliability of rubber parts. The permanent seal and the safety of the later period cannot be guaranteed. In addition, when the hanger with a sealed structure is lowered, the hanger sits and hangs on the four-way step, which will form a seat seal blind area, making it difficult to judge the lower seal, and it is not convenient to replace the seal components. For The completion, oil production and gas production operations of ultra-deep, ultra-high pressure and high-sulfur oil and gas wells bring safety risks. In order to overcome the above-mentioned difficulties and the defects of the existing sealing structure, ensure the permanent safety of oil and gas production operations and prevent later seal leakage Failure accident, this patent designs a mandrel-type hanger with all-metal multi-stage and equal-cone seal structure. This patent can be used in the long-term mining process with a very high safety margin. Here, the multi-stage all-metal Under the protection of the sealing barrier, it is impossible for the production layer fluid to leak directly into the atmosphere

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