The wall thickness requirements of LSAW Steel Pipes in the field of oil and gas transportation usually depend on multiple factors, such as the design pressure, design temperature, characteristics of the conveying medium, pipeline diameter, pipe steel grade, and application standards. Here are some relevant requirements and standards:

Related standards

API SPEC 5L： The American Petroleum Institute standard specifies the size, steel grade, and performance of steel pipes used for transportation in the oil and gas industry. When the outer diameter of the steel pipe is ≥ 60.3mm and the wall thickness s<20mm, the allowable deviation of the outer diameter is ± 0.75%; When the outer diameter is ≥ 60.3mm and the wall thickness s is ≥ 20mm, the allowable deviation of the outer diameter is ± 1.00%. For steel pipes of different grades, such as X42, X52, X60, X65, X70, etc., there are different mechanical performance requirements, and wall thickness is one of the important factors affecting the mechanical performance of steel pipes to meet the standards.

GB/T 9711： The Chinese national standard, equivalent to ISO 3183, specifies the technical requirements for steel pipes used in the transportation of petroleum and natural gas industries. GB/T 9711.1 is applicable to PSL1 grade steel pipes, while GB/T 9711.2 is applicable to PSL2 grade steel pipes. It specifies the dimensional tolerances, materials, mechanical properties, and process performance of steel pipes, including allowable deviations in wall thickness. For example, when the outer diameter D of the pipe is less than 508, the allowable deviation in wall thickness is ± 12.5% t; When D ≥ 508, the allowable deviation of wall thickness is ± 10.0% t.

Wall thickness range in different application scenarios

Long distance onshore pipelines: For large-diameter onshore oil and gas pipelines, when using X70 grade LSAW steel pipes, the common wall thickness range is around 8-26.4mm; If X80 steel grade is used, the wall thickness is generally between 6.4-23.8mm. For example, in some main pipelines of the West East Gas Pipeline, steel pipes with such a range of wall thickness are used. For branch pipelines with low conveying pressure and small diameter, when using steel grades such as X42-X60, the wall thickness may be around 6-12mm.

Offshore oil and gas transmission pipelines: Due to factors such as seawater pressure and corrosion, the wall thickness requirements are relatively high. In shallow sea areas, LSAW steel pipes of X65-X70 steel grade may be used, with a wall thickness of 12-30mm; In deep-sea environments, for pipelines that withstand high pressure, using high-strength steel grades such as X80 and X100 may result in wall thicknesses ranging from 16-40mm or even thicker. Such thick walled steel pipes are needed to ensure safe transportation of deep-sea oil and gas fields to land pipelines.

Internal gathering and transmission pipelines in oil and gas fields: The pressure and diameter of gathering and transmission pipelines vary greatly. The gathering and transmission branch lines inside the oil and gas field have low transmission pressure and use X42-X52 steel grade. When the pipe diameter is between 200-400mm, the wall thickness may be between 4-8mm; In the gathering and transmission trunk line, the pressure is relatively high, and X60-X70 steel grade is used. When the pipe diameter is between 400-800mm, the wall thickness may be between 8-16mm.

The following are the applicable scenarios of LSAW steel pipes with different wall thicknesses in the field of oil and gas transportation:

Thin walled LSAW steel pipe (wall thickness<8mm)

Urban gas distribution pipeline network: In the gas distribution system within the city, the pressure is relatively low, generally in the range of medium and low pressure (such as 0.01MPa to 0.4MPa). For pipelines with small diameters, such as DN100-DN300, thin-walled LSAW steel pipes can meet transportation requirements and have advantages such as low cost and convenient construction. For example, the natural gas pipeline in urban residential areas usually uses this thin-walled steel pipe, which can safely transport natural gas to various users' homes.

Low pressure gathering and transmission branch lines within oil and gas fields: In the early stages of oil and gas field development or in some low production areas, the collection and transportation pressure of oil and gas is relatively low. For gathering and transmission branch lines with short transportation distances and low flow rates, such as pipelines connecting single wells to gas or oil gathering stations, using thin-walled LSAW steel pipes can reduce costs and facilitate installation and maintenance. For example, some small oil and gas fields use this type of steel pipe for their internal gathering and transportation systems.

Medium wall thickness LSAW steel pipe (8mm ≤ wall thickness < 16mm)

Branches of onshore oil and gas long-distance pipelines: In onshore oil and gas transportation, medium wall thickness LSAW steel pipes are more suitable for some long-distance pipeline branches with moderate diameter and low transmission pressure. For example, pipelines that branch oil and gas from main pipelines to surrounding cities or industrial users generally have a pressure of around 1MPa to 4MPa. The use of X52-X65 steel grade steel pipes with a wall thickness of 8mm-12mm can ensure the strength and sealing of the pipeline, while also considering economy.

Internal pipelines of offshore oil and gas platforms: Within offshore oil and gas platforms, pipelines are used to connect different equipment and processing units. Due to limited space, there are certain requirements for the corrosion resistance and strength of steel pipes, but the pressure is relatively low compared to the platform's external pipelines. LSAW steel pipes with medium wall thickness can meet these requirements, such as the connecting pipelines inside the crude oil processing system and natural gas purification system on the platform. Using steel pipes with wall thickness of 10mm-16mm can adapt to the complex environment of the platform while ensuring safety.

Thick walled LSAW steel pipe (16mm ≤ wall thickness < 25mm)

Onshore high-pressure oil and gas long-distance transmission trunk line: For large-scale onshore high-pressure oil and gas long-distance transmission trunk lines, such as national level natural gas transmission pipelines such as the West East Gas Pipeline, with high transmission pressure (generally between 4MPa and 10MPa or even higher) and large pipe diameter (such as DN800-DN1400), thick walled LSAW steel pipes are required to ensure the safety and reliability of the pipeline. High strength steel grades such as X70 and X80, with wall thicknesses ranging from 16mm to 22mm, are usually selected to withstand enormous internal pressure and external loads.

Export pipeline from offshore oil and gas fields to land: The export pipeline from offshore oil and gas fields to land receiving terminals must withstand the pressure and corrosion of seawater while ensuring high-pressure transportation of oil and gas. For example, in waters with a depth of 100-500 meters, thick walled LSAW steel pipes with a wall thickness of 18mm-25mm, combined with appropriate anti-corrosion coatings and cathodic protection measures, can safely transport oil and gas to land.

Extra thick walled LSAW steel pipe (wall thickness ≥ 25mm)

Ultra high pressure oil and gas transmission pipelines: In some special oil and gas transmission scenarios, such as ultra-high pressure natural gas storage and transmission systems, and the development of deep-sea high-pressure oil and gas fields, thick walled LSAW steel pipes are required. The conveying pressure of these pipelines is extremely high (over 10MPa), and the requirements for the strength and toughness of steel pipes are very strict. For example, in some underground gas storage facilities, thick walled steel pipes with a wall thickness of 25mm or more are used in the gas injection and production pipelines to ensure the safe operation of the pipelines under long-term high-pressure cycling conditions.

Oil and gas pipelines in extreme environments: In extreme environments such as high cold and high altitude, oil and gas pipelines not only need to withstand high pressure, but also need to resist the influence of factors such as low temperature and geological disasters. LSAW steel pipes with extra thick walls have better deformation resistance and low-temperature toughness, and can adapt to these harsh conditions. For example, in oil and gas development projects in the Arctic region, steel pipes with a wall thickness of 30mm or even thicker will be used to construct transmission pipelines.