What Is The Difference Between Line Pipe And OCTG Pipe?

What is line pipe?

‌Line pipe is a kind of pipeline used to transport oil, gas and water, mainly used in the oil and gas industry. The main function of line pipe is to transport oil, gas and water extracted from the ground to oil and gas industrial enterprises through pipelines. It includes two types of seamless pipe and welded steel pipe, and the pipe ends are in various forms such as flat ends, threaded ends and socket ends. Its connection methods are diverse, including end welding, coupling connection, socket connection, etc. Its main features are pressure resistance and corrosion resistance. 

Line pipes can be divided into different grades and specifications according to different uses and pipeline design standards. At present, the commonly used international standards for line pipes are API 5L, ISO 3183, etc., while the domestic standard adopts GB/T 9711. The manufacturing process of line pipes is generally divided into hot rolling and cold drawing. Among them, hot-rolled line pipes have a smooth surface and are widely used, but the cost is high; cold-drawn line pipes have a high surface finish, long service life and low cost.

What is OCTG pipe?

OCTG pipe refers to a pipe used for underground extraction of oil, natural gas, etc. Its main features are smooth inner and outer walls, high pressure resistance, and strong corrosion resistance. The slight difference is that the steel properties of OCTG pipes correspond to line pipes. Similarly, OCTG pipes also have various specifications and grades according to the requirements of downhole operations and drilling processes. OCTG pipes include drill pipe, API 5CT casing pipe, oil pipes and other pipes. 

The manufacturing process of OCTG pipes includes hot rolling of steel plates, fine burr processing of pipe billets, rolling, straightening, synthesis, welding, cleaning, dimensional inspection and other links. Among them, the manufacturing difficulty of OCTG pipes is greater than that of line pipes, so its production cost is also relatively high.

What is the difference between line pipes and OCTG pipes?

1. Uses and characteristics

1‌) Line pipes

Mainly used for long-distance transportation of oil and natural gas, usually used to connect oil wells and natural gas processing facilities. Line pipes can be seamless pipes or welded pipes, and their pipe ends have flat ends, threaded ends and socket ends. The connection methods include end welding, coupling connection, socket connection, etc.

2) OCTG pipe

Steel pipes specially used for oil and gas extraction, including oil pipe, casing pipe and drill pipe. Most OCTG pipes are seamless pipes, but welded pipes also account for a considerable proportion. They play a key role in the process of oil and gas extraction, such as oil pipes are used to transport oil from the oil layer to the ground, casing is used to fix the well wall of the oil well, and drill pipes are used for drilling.

2. Material and performance

1‌) ‌Line pipe

Usually made of high-strength steel, it can withstand high pressure and high temperature environment. Its chemical composition, tensile properties, yield strength and hardness are strictly required to ensure stability and safety during transportation.

2) ‌OCTG pipe

According to the API grading method, OCTG pipes are divided into different steel grades and specifications, from low steel grades to high steel grades. OCTG pipes of different steel grades have different metal element compositions and performance requirements to meet different mining needs. 

Summary

In general, there are certain differences between line pipe and OCTG pipe in terms of physical properties, uses, production processes, etc., but both are indispensable and important materials in the oil and gas industry, providing a solid guarantee for the exploitation and transportation of oil and gas.