Anti-sticking three-stage end face metal seal titanium alloy pipe thread joint

Abstract

The invention relates to a threaded structure for connection of a well completion production tubular column of the petroleum and gas industry, in particular to an anti-bonding three-stage end surface metal sealing threaded connector for a titanium alloy pipe. The anti-bonding three-stage end surface metal sealing threaded connector for the titanium alloy pipe comprises an oil casing collar and an oil casing end, wherein the oil casing collar is provided with an API buttress inner thread, the oil casing end is provided with a buttress outer thread matched with the API buttress inner thread, a tool withdrawal groove is formed in one end of the API buttress inner thread and is sequentially connected with an arc surface I and an arc surface II through chamfer transition, the arc surface II is connected with a negative angle torque lifting shoulder I through chamfer transition, a conical surface, a cylindrical surface and a negative angle torque lifting shoulder II are arranged at one end of the buttress outer thread, the conical surface and the cylindrical surface sequentially correspond to the arc surface I and the arc surface II, the negative angle torque lifting shoulder II corresponds to the negative angle torque lifting shoulder I, and after the oil casing collar is matched with the oil casing end in a threaded mode, interference sealing is carried out on metal through a first-stage sealing structure of the arc surface I on the conical surface, a second-stage sealing structure of the arc surface II on the cylindrical surface and third-stage metal of the sealing structure of the negative angle torque lifting shoulders. The anti-bonding three-stage end surface metal sealing threaded connector for the titanium alloy pipe improves the air sealing reliability, and has good anti-bonding performance.

Description

technical field [0001] The invention relates to a thread structure for the connection of well completion and production pipe strings in the petroleum and natural gas industry, in particular to a three-stage end face metal seal titanium alloy pipe thread joint with anti-sticking. Background technique [0002] With the further deepening of oil and gas development, many oil and gas fields in western China and southwest my country have high temperature (greater than 140°C), high pressure (greater than 100MPa), well depth (greater than 5000m) and high corrosive media (C0 2 、H 2 S, CL-) and other harsh environments, in order to meet the corrosion resistance requirements of oil and gas field development in these oil and gas fields, titanium alloy pipes have been introduced into the manufacture of oil and casing, and have very excellent performance. [0003] In the development process of the oil and gas industry, the oil casing used is a string composed of threaded connections. The...

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Problems solved by technology

Due to the congenital deficiencies in the structural design of the ordinary API thread, it cannot meet the sealing integrity in the "three high" oil and gas field environments such as high temperature, high pressure, and high corrosive medium content, and is prone to serious oil and gas leakage accidents. contains H 2 Toxic substances such as S pose a great threat to oil and gas safety, the surrounding ecological environment, and the safety of people's lives and property; at the same time, titanium alloy materials have the characteristics of low elastic modulus, low surface hardness, poor wear resistance and low thermal conductivity. , processing ordinary API threads with titanium alloy materials is prone to sticking, and the general special thread structure designed based on steel materials is not suitable for titanium alloy oil pipes, which are prone to sticking and sealing failure. Therefore, in order to ensure the "three highs" "The safe development of oil and gas fields has also further promoted the promotion and application of titanium alloy oil casings in the oil and gas industry. There is an urgent need for a special thread structure designed for titanium alloy materials with structural integrity, reliable sealing performance and anti-sticking.

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