The requirements for pipelines in the construction of oil and gas pipelines involve many aspects, mainly including the following points:

Material requirements

High strength and high toughness: Oil and gas pipelines need to withstand the high pressure of internal fluids and various stresses of the external environment. Therefore, pipeline materials are required to have high strength, such as high-strength steels such as X70 and X80, to ensure that no accidents such as rupture occur under high pressure. At the same time, it is also necessary to have high toughness and be able to maintain good performance under conditions such as low temperature and impact to prevent brittle fracture.

Corrosion resistance: Oil and gas may contain corrosive media such as hydrogen sulfide, carbon dioxide, and water. External environments such as soil and groundwater may also cause corrosion to pipelines, so pipeline materials must have good corrosion resistance. Usually, corrosion-resistant alloy steel is used or anti-corrosion coatings and linings are added to the surface of carbon steel, such as polyethylene anti-corrosion layers and epoxy powder coatings.

Good weldability: In order to achieve the connection and laying of pipelines, pipeline materials need to have good weldability, ensure welding quality, reduce welding defects, and make the welds have strength and performance equivalent to the pipe body.

Size and specification requirements

Pipe diameter: Determine the appropriate pipe diameter according to the amount of oil and gas transported. Generally speaking, the diameter of the main pipeline for long-distance transportation is larger, such as 1016 mm, 1219 mm, etc.; while the diameter of the branch pipeline or urban gas pipeline is relatively small, and the common ones are 219 mm, 325 mm, etc.

Wall thickness: The wall thickness of the pipeline needs to be calculated and determined based on factors such as design pressure, pipe diameter, and material strength. The higher the pressure and the larger the pipe diameter, the thicker the wall thickness required. At the same time, factors such as the strength reserve and corrosion allowance of the pipeline under different working conditions must also be considered.

Length and pipe segment size: In order to facilitate transportation and construction, the pipeline usually has a certain standard length, such as the general steel pipe length of about 12 meters. There are also strict requirements for the dimensional accuracy of the pipe segment, such as ovality and straightness, to ensure the sealing and overall quality of the pipeline connection.

Performance requirements

Pressure bearing capacity: The pipeline must be able to withstand oil and gas transportation under the design pressure, and can work safely and reliably under normal operation and possible pressure fluctuations, water hammer and other working conditions. The design pressure is generally determined according to the production pressure, transportation distance, topography and other factors of the oil and gas field. Common design pressures include 6.4MPa, 10MPa, 12MPa, etc.

Sealing: The sealing of oil and gas pipelines is crucial. Any leakage may lead to oil and gas loss, environmental pollution and even safety accidents. The connection parts of the pipeline, such as welds, flanges, threads, etc., need to be strictly sealed. Sealing materials such as sealing rubber rings and sealing gaskets are usually used, and strict testing methods such as pressure testing and leakage detection are used to ensure the sealing of the pipeline.

Anti-fatigue performance: During the long-term oil and gas transportation process, the pipeline will be subjected to alternating stress caused by factors such as internal pressure, temperature changes, and soil movement. Therefore, the pipeline is required to have good anti-fatigue performance to ensure that there will be no fatigue cracks and damage within the design service life.

Safety and environmental protection requirements

Fire prevention and explosion prevention: Since oil and natural gas are flammable and explosive, fire prevention and explosion prevention measures must be considered in pipeline construction. Pipelines should avoid densely populated areas, flammable and explosive places, etc. At the same time, fire isolation belts and fire-fighting facilities should be set up along the pipeline. Pipeline materials and coatings should have certain flame retardant properties to reduce the risk of fire and explosion.

Environmental performance: During the construction of pipelines, the impact on the environment should be minimized. Pipeline materials should meet environmental protection requirements and avoid using materials that pollute the soil, water sources, etc. During the construction process, measures should be taken to prevent soil erosion and protect the ecological environment. After the construction is completed, ecological restoration should be carried out in a timely manner.