What is special thread for oil casing pipe

At present, oil well pipes (oil pipes, casing pipes, and drilling tool pipes) are all API standards (American Petroleum Institute). The domestic standards are basically converted according to the API standards. The specific oil fields also implement API standards, special threads. It is relative to the API thread (the main model is the long round thread and the partial trapezoidal thread), the special thread is generally developed by the sleeve manufacturer and has patent protection. The international use is based on the VAM buckle and the VAM buckle. Development of NEW VAM, VAM-top and other types of buckles, domestic use of many VAM deductions (developed by Warruk and Mannesmann), TM deduction (Sumitsu Metal Development), FOX deduction (Kawasaki Steel and NKK merger After the development of JFE company.

The major domestic companies are Pancheng Yihong Co., Ltd., which is jointly invested with Pancheng Steel. In addition, TP-CQ series buckles developed by Tiansteel, BGT series buckles of Baosteel, WSP series buckles of Wuxi Simles, and HSM series of Henggang. Buckle, which has been developed in recent years and certified by relevant authorities, has been tested in major domestic oil fields, and a large part of it is used for export.

The special threaded oil casing is mainly used in wells that are not adapted to the traditional API threads. The traditional API threads have problems such as tightness and tensile strength. The traditional API threads have poor air sealing performance and contain wells such as hydrogen sulfide, carbon dioxide and chloride ions. The wells are not adapted, and special threads can effectively overcome these disadvantages. In addition, some high-grade steel pipes (such as N80 pipe and above steel grades) generally use special threads.

The API sleeve thread is not suitable for the development of high-pressure gas fields, so many manufacturers have developed special fittings with various characteristics, among which the special types of gas seal special fittings for developing gas fields are:1, NS-CC thread (developed by Nippon Steel, Japan), its main features are: 1) The thread adopts improved API eccentric trapezoidal thread. The tensile strength of the joint is high; 2) Tapered face taper face metal main seal and inner shoulder metal secondary seal. Make joints have good airtight performance; 3) The stepped double straight shoulder structure enables the joint to have good resistance to over-twist and bending, and is beneficial to protect the main seal; 4) The lower hoop stress on the joint is conducive to preventing stress corrosion cracking.2, Fox thread (Japan Kawasaki Steel and British Hunting company jointly developed).3, TM thread (Japan Sumitomo Metal has been improved on the basis of VAM thread design)4, SEC thread (designed and produced by Argentina Siderca)

A worker from a steel pipe company, which is located in China.