Special Connections byTianjin Grand Victory Petroleum Equipment Co.,Ltd

Product Name: Casing Coupling, Tubing Coupling, API 5CT Couplings, OCTG Couplings

Size: Tubing Coupling : 1.9'' - 4-1/2'',Casing Couping : 4-1/2'' - 13-3/8''
Thread Type: NUE/EUE/STC/LTC/BTC
Grade: J55, L80, N80 & P110
Standard: API 5CT and 5B PSL1/PSL2 J55,K55,N80-1,N80-Q, API 5CT and 5B L80-1,C90, C95,T95, P110, Q125
Surface Treatment: phosphating treatment

The American Petroleum Institute (API) has established standards for various aspects of the oil and gas industry, including specifications for thread connections used in oil casing. The API standard for thread connections for oil casing is known as API Spec 5B. Commonly used API-certified threaded connections include the Short Round Thread (STC), Long Round Thread (LTC), and Buttress Thread (BTC). API Standard Thread Connections for Oil Casing LTC (Long Round Thread) Type: This type features a non-bounce design with round threads, consisting of eight dome threads per inch, similar to the STC model. LTC threads are known for their ease of processing, excellent sealing performance, robust connection strength, straightforward maintenance, and cost-effectiveness. Widely applied in the oil and gas industry, LTC threads are particularly suitable for scenarios involving some axial loads, provided the overall well conditions do not entail extreme temperatures or pressures. STC (Short Round Thread) Type: STC thread type is characterized by a round thread with a runout-free design, comprising eight dome threads per inch. Capable of withstanding 60% to 80% of the pipe strength, STC threads are well-suited for shorter length casing applications without high axial loads or bending requirements. BTC (Buttress Thread) Type: Designed to enhance axial tension or axial compression load capacity while ensuring leak resistance. BTC threads serve as an excellent connection choice for well conditions that involve high axial loads, along with moderate internal pressures and temperatures. It's important for manufacturers and users in the oil and gas industry to adhere to these API standards to ensure the reliability and safety of threaded connections in oil casing. Compliance with API Spec 5B helps in maintaining consistency and compatibility across different components in the industry, facilitating efficient and secure operations.

API casing threads are not suitable for the development of high-pressure gas fields, so many manufacturers have developed special joints with their own characteristics. Among them, the gas-sealed special joint thread types suitable for the development of gas fields are:
1. NS-CC thread (developed by Nippon Steel), its main features are:
1) The thread adopts improved API partial trapezoidal thread. High tensile strength of the joint;
2) Cone surface and cone surface metal main seal and inner shoulder metal secondary seal, so that the joint has good air tightness;
3) The stepped double straight shoulder structure makes the joint have good anti-torsion and bending ability, and is beneficial to protect the main seal;
4) The circumferential stress on the joint is lower, which helps prevent stress corrosion

2. Fox thread (co-developed by Kawasaki Steel in Japan and Hunting in the UK).

3. TM thread (Japan Sumitomo Metal's improved design based on VAM thread)

4. SEC thread (designed and produced by Siderca, Argentina) Expansion information:

At present, oil well pipes (tubing, casing, and drilling tool pipes) are all implemented API standards (American Petroleum Institute), and China’s standards are basically converted in accordance with API standards. Major oilfields implement API standards and special threads. Compared with API threads (the main models are long round threads and partial trapezoidal threads), special threads are generally developed by casing manufacturers and have patent protection. The most widely used internationally are VAM buckles and VAM buckles based on the development of NEW VAM, VAM-top and other buckle types, and the most used domestically are VAM buckles (developed by Varurek and Mannesmann), TM buckles ( Sumitomo Metal Development), FOX buckle (developed by JFE Company after the merger of Kawasaki Steel and NKK). They have been tested in major oil fields in China, and a large part of them are exported. Special threaded oil casing pipe is mainly used in wells where traditional API threads are not suitable. Traditional API threads have problems such as sealing and tensile strength. Traditional API threads have poor air-tightness. For wells containing hydrogen sulfide, carbon dioxide and chloride ions, Special threads can effectively overcome these shortcomings. Other high-grade steel pipes (such as Q125 and above) generally use special threads.

Tips: ASTM A53 Gr.B is the grade in ERW high frequency welded pipe, divided into A and B grades. ASTM is only a set of specifications. ASTM steel pipe A53 A corresponds to the Chinese standard GB8163 raw material is 10# steel, and A53 B corresponds to the Chinese standard GB8163 raw material 20#. For example: ASTM (standard) A53 (grade) gr (abbreviation of grade) b (grade B)

Product Features

High Strength and Toughness: Ensures reliability in highpressure and complex environments.
Excellent Sealing Performance: Advanced thread design and machining technology ensure the sealing of connections.
Corrosion Resistance: Suitable for corrosive environments such as high hydrogen sulfide.
HighPrecision Manufacturing: CNC lathes and automatic flaw detectors are used to ensure thread accuracy and dimensional tolerances meet international standards.

Customization Services

The company offers customization services and can design and manufacture unique connection types according to customers' special requirements to meet the needs of specific projects or special environments.

Application Scenarios

Special connections are widely used in:
Onshore and offshore petroleum and natural gas extraction
Tubular connections in deep wells and highpressure wells
Oil and gas extraction in high hydrogen sulfide environments
Tubular connections during oilfield development and production

Product Advantages

High Strength and Toughness: Ensures reliability in highpressure and complex environments.
Excellent Sealing Performance: Advanced thread design and machining technology.
Corrosion Resistance: Suitable for corrosive environments such as high hydrogen sulfide.
Customization Services: Meets customers' special needs.