Sunrise petro : Three main types of OCTG threading

‌Oil Country Tubular Goods (OCTG) pipes play a crucial role in the oil and gas industry, where they are used for various drilling and production applications. The threaded connections of OCTG pipes simplify installation and coupling in the well, ensuring a secure connection that can withstand the demands of the harsh downhole environment.

There are three main types of OCTG threading: Short Round Thread Casing (STC), Long Round Thread Casing (LTC), and Buttress Thread Casing (BTC).

1. Short Round Thread Casing (STC): This type of threading is a good choice for shorter-length casing applications that do not involve high axial loads or bending. The STC design features a short thread length, which reduces the stress on the connection, making it suitable for use in shorter casing sections where axial loads are not significant.
2. Long Round Thread Casing (LTC): This threading type is well suited for situations where some axial load is encountered but overall well conditions do not include extremes of temperature or pressure. The LTC design offers a longer thread length, providing greater strength and fatigue resistance, making it suitable for longer casing sections or where mild axial loads are present.
3. Buttress Thread Casing (BTC): This is a popular threading type due to its combination of strength and durability. The BTC design features a thicker thread root and flattened crests, which provide additional resistance to axial and bending loads. It is suitable for use in wells with high axial loads, bending moments, and temperature and pressure extremes.

Each type of OCTG threading has its specific applications and advantages based on the well conditions and requirements. Understanding the characteristics and limitations of each threading type is crucial for selecting the appropriate OCTG pipe and threading design for a particular drilling or production operation.