Special screw thread joint of high air-tight seal oil sleeve

A special thread and air-tight technology, which is applied in the direction of casing, drill pipe, drilling equipment, etc., can solve the problems of special thread corrosion, leakage, over-torque, sticking and other problems of the downhole pipe string, and achieve the prevention of stress corrosion, low contact stress, The effect of ensuring integrity

Active Publication Date: 2012-11-14
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0006] The purpose of the invention is to solve the problems of corrosion leakage and over-torque sticking of the special thread of the downhole pipe string

Method used

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  • Special screw thread joint of high air-tight seal oil sleeve

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Embodiment Construction

[0020] The thread of the special threaded joint of the high air-tight oil casing pipe according to the present invention is composed of corresponding internal and external threads, and the structure starts from the front end in order of auxiliary shoulder 1, first-level main seal 2, main shoulder 3, and second-level Main seal 4, guide surface 5, bearing surface 6;

[0021] The auxiliary shoulder is a corresponding right-angle structure with a width of 1.0-1.5mm; the first-stage main seal is a conical surface corresponding to a conical surface structure, the length is 4-5mm, and the taper is 1:7-10, connecting the auxiliary shoulder and the main shoulder; The shoulder is the corresponding reverse shoulder structure, the shoulder width is 2~2.5mm, the shoulder angle is 15~20°, the shoulder transition arc radius is 0.2~0.5mm; the secondary main seal is a spherical surface corresponding to the conical surface structure, the spherical surface is round The radius of the arc is 10-20...

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Abstract

The invention relates to a special screw thread joint of a high air-tight seal oil sleeve, which comprises an auxiliary circular bead, a first-level primary seal, a second-level primary seal, a guide surface and a bearing surface sequentially beginning from the front end part, wherein the auxiliary circular bead is a corresponding right-angle structure and has the width of 1.0-1.5mm; the first-level primary seal is a conical surface / conical surface structure, has the length of 4-5mm and the tapering of 1:7-10 and is connected to the auxiliary circular bead and a main circular bead; the main circular bead is a corresponding reverse circular bead structure and has the width of 2-2.5mm, the angle of 15-20 degrees and the transition arc radius of 0.2-0.5mm; the second-level primary seal is a spherical surface / conical surface structure, the arc radius of the spherical surface is 10-20mm, the length of the conical surface is 4-5mm, and the tapering is 1:7-10; the primary seal is connected to the main circular bead and the guide surface of a screw thread, the positive angle of the guide surface is more than 10-15 degrees, and the negative angle of the screw thread bearing surface is less than minus 3 degrees; and the preventive stress corrosion and the sealing property are better than those of a single-level circular bead and a sealing structure.

Description

Technical field: [0001] The invention relates to a special threaded joint of a high-gas-tight oil-casing pipe for ensuring the safe exploitation of high-temperature, high-pressure and corrosive medium-containing natural gas wells. Background technique: [0002] In the development of oil and gas, the oil / casing used is an oil / casing string composed of threaded connections. The thread is the weakest link in the string, and its structural integrity, sealing integrity and reliability seriously affect the Oilfield safety production and string life. PetroChina West Oilfield is characterized by high temperature, high pressure and corrosive media. Due to the complex structure of the screw thread, serious stress concentration will occur after make-up, especially at the shoulder angle of the torque shoulder. Under the action, the contact pressure of the main sealing surface decreased significantly, resulting in serious natural gas leakage in threaded joints. [0003] For high-tempe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B17/08
Inventor 王建东冯耀荣林凯杨龙王新虎刘文红
Owner BC P INC CHINA NAT PETROLEUM CORP
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