What is a petroleum pipeline?

What is a petroleum pipeline?

The petroleum pipeline is composed of the oil pipe and its accessories, and is equipped with the corresponding oil pump unit according to the needs of the process flow. It is designed and installed as a complete pipeline system for completing the oil material loading and unloading and transportation tasks.

The petroleum pipeline system, which is a pipeline system for transporting petroleum and petroleum products, is mainly composed of petroleum pipelines, oil stations and other auxiliary related equipment. It is one of the main equipments in the petroleum storage and operation industry, and is also the main oil and petroleum products. Compared with the railway and highway oil transportation that belong to the land transportation mode, the pipeline transportation has the characteristics of large transportation capacity, good airtightness, low cost and high safety factor.
The pipes of the petroleum pipelines are generally steel pipes, which are connected by connecting devices such as welding and flanges, and use valves for opening and closing control and flow regulation. The petroleum pipeline mainly has conveying processes such as isothermal conveying, heating conveying and sequential conveying. Corrosion of pipelines and how to prevent corrosion are one of the important aspects of pipeline maintenance. At present, petroleum pipelines have become one of the main transportation tools for petroleum, and they still have considerable development potential in the future.

Types of Petroleum Pipeline Specification Oil pipeline layout
Composition of the piping system Petroleum pipeline connection and control China’s oil pipeline
Materials and specifications Corrosion and corrosion protection of oil pipelines World’s major oil pipelines

Types of Petroleum Pipeline

By distance

  1. The petroleum pipeline inside the enterprise: the internal petroleum pipelines of the enterprise mainly refer to the petroleum pipelines connected to the oil wells and metering stations, the joint stations, the oil refineries and the pipelines inside the oil depots. The length is generally short and is not an independent operation system.
  2. Long distance petroleum pipeline: pipes that transport crude oil or refined oil over long distances. The transportation distance can reach hundreds or thousands of kilometers. The annual oil transportation volume of a single pipe is between several million tons and several tens of thousands tons. Individually, it has 100 million tons, and the pipe diameter is more than 200mm. The largest one is now 1220mm. . Its starting point and end point are connected to other oil companies such as oil fields and oil refineries. It consists of two parts: the oil station (including the first station, the last station, the intermediate pump station and the heating station, etc.) and the pipeline. The latter includes the main pipeline section, and the cross-over project when passing through natural obstacles such as rivers, canyons and seabeds. The cathodic protection system for preventing pipeline corrosion, the simple road and line cut-off valve room built for inspection and maintenance. . Most oil companies also have a complete set of independent communication systems, including communication lines and relay stations.

By types of crude oil

76 - What is a petroleum pipeline?

  1. Crude petroleum pipeline: crude petroleum pipelines mainly refer to pipelines that transport crude oil products, which are different from refined petroleum pipelines. The main crude petroleum pipelines currently operating in China are Sino-Russian crude petroleum pipelines and Central Asian crude petroleum pipelines.
  2. Refined petroleum pipeline: the refined petroleum pipeline is a pipeline for long-distance transportation of refined oil. Now there are many refined petroleum pipelines in China that are already in operation or under construction, mainly including: Lanchengyu refined petroleum pipeline and Lanzheng Chang petroleum pipeline and Yaang Pipe Industry Co., Limited.

By material

  1. Carbon steel pipe: the fixed petroleum pipelines are mostly made of carbon steel pipes. The carbon steel pipes can be divided into seamless steel pipes and welded steel pipes according to the manufacturing method. The seamless steel pipes are divided into hot rolling and cold drawing. The usual carbon steel pipes are all made of boiling steel. Manufacture, temperature range is 0~300°C, easy to embrittle at low temperature, steel pipe made of high quality carbon steel, temperature range is -40~450°C, 16Mn steel is used, temperature range is -40°C, The high temperature can reach 475 °C.
  2. Oil resistant hose: the oil-resistant hose is an petroleum pipeline mainly used for temporary loading and unloading of oil transfer facilities or active parts of pipelines.

The oil resistant hose has oil-resistant cloth hose, oil-resistant spiral hose and oil-steel wire braided hose, all made of nitrile rubber. And divided into three different conditions of pressure, suction and discharge, positive pressure conveying should use pressure hose, negative pressure conveying is the use of suction hose, there may be positive and negative pressure when the need to use suction hose.

The composition of the piping system

20180410102048197 - What is a petroleum pipeline?

  • Oil station: the long distance oil pipeline consists of two major parts: the oil station and the pipeline. The starting point of the pipeline is a gas station, commonly known as the “first stop”. After the oil or crude oil is collected at the first station, it is metered and then powered by the first station to the downstream pipeline. The first station is generally equipped with an oil storage tank, an oil pump and an oil metering device. If the oil is heated due to high viscosity, a heating system is also provided. The oil pump provides power so that the oil can move along the pipeline to the end point or the next-stage oil station. Under normal circumstances, due to the long distance, the energy loss of the oil during transportation is obvious, and the multi-stage oil station needs to be powered until Deliver the oil to the end point. The oil station at the end point is called the “last station” and is mainly responsible for collecting the materials from the upstream pipeline. Therefore, it is also equipped with storage tanks and metering systems.
  • Pipeline: the pipeline part of the long-distance oil pipeline system is mainly composed of the following equipment: the main body of the pipeline; the valve along the line and its control system; the crossing facilities through rivers, highways and mountains; the cathodic protection device and the simple road, communication system, and staff The residence and so on. The long-distance oil pipeline is welded by steel pipe, and the outer layer of the pipe is covered with an insulating layer material to prevent the corrosive chemical components in the soil from eroding the pipeline body. The pipeline body can also be coated with anti-corrosion materials to reduce the oil itself. Corrosion of pipelines and improved smoothness of pipelines to increase transportation. At regular intervals or across large obstacles, the pipeline is equipped with valves to block material in the event of an accident, to prevent accidents from expanding and to facilitate maintenance of equipment. Communication equipment is an important command tool for the transmission and dispatch of oil pipelines. With the development of communication satellites and automation technology, related technologies have been widely used in the pipeline transportation of oil products.

Materials and specifications
Pipe and suitability

The pipes used in oil pipelines are mainly carbon steel pipes, which can be divided into seamless steel pipes and welded steel pipes according to their manufacturing processes. Seamless steel pipe has the characteristics of high strength and many specifications, so it is suitable for oils with strong corrosiveness or transportation under high temperature conditions. Seamless steel tubes are divided into hot rolling and cold drawing. Since the cold drawing process causes the material to harden, it is also necessary to perform a corresponding heat treatment depending on the specific use of the pipe. Welded steel pipes can be divided into two types: welded steel pipes and welded welded pipes. Due to the process characteristics of carbon steel pipe, the steel pipe is easy to become brittle at low temperature, so it is mainly suitable for normal temperature pipelines. The use temperature of the pipe should not exceed 300 degrees Celsius. Generally, the temperature of common carbon steel pipe is between 0 and 300. Between degrees Celsius. If high-quality carbon steel pipe is used, the temperature application range and relaxation can reach -40 to 450 degrees Celsius. The experimental pressure of a steel pipe is generally 1.5 times the nominal pressure. When the temperature of the material being conveyed does not exceed 200 degrees Celsius, the working pressure is the nominal pressure. When the temperature exceeds 200 degrees, the working pressure should be lower than the nominal pressure.

Specification type

The outer diameter of the steel pipe is generally indicated by a capital letter D, and the value of the outer diameter is added to the rear. For example, a steel pipe with an outer diameter of 400 mm is represented by D400; the inner diameter of the steel pipe is indicated by a lowercase d of the letter, and an inner diameter value, such as an inner diameter, is added thereafter. The steel pipe of 300 is expressed as d300; the specification of the steel pipe is generally expressed by “Φ outer diameter × wall thickness”, for example, the outer diameter is 400 mm, and the pipe having a wall thickness of 6 mm is expressed as Φ400 × 6. Common steel pipe specifications are shown in the following table:

Type of steel pipe
Standards of steel pipes 
Nominal diameter(DN,mm)
Applicable temperature range(°C)
Seamless steel pipe
A312, A333, A790, A999, YB231—70
A312, A333, A790, A999, A106, SYB10004—63
Steel coiled tube
A312, A333, A790, A999, YB234—63

Important parameters

  • Nominal diameter: The nominal diameter is a standard diameter specified for the design, construction and maintenance of pipes. In general, the nominal diameter is not equal to the actual inner or outer diameter of the pipe, but rather an integer value that is closer to the inner diameter. The nominal diameter is characterized by the symbol “DN”, followed by the addition of specific values, for example: an oil pipeline with a nominal diameter of 600 mm is indicated as “DN600”. The nominal diameter also often uses “inch” as the unit, 1 inch = 25.4mm, in order to facilitate the conversion operation generally takes “1 inch ≈ 25mm”, the DN600 oil pipeline can be called “24 inch”.
  • Pressure parameters: The pressure parameters of the pipeline are “nominal pressure”, “test pressure” and “working pressure”. The nominal pressure is the nominal pressure parameter of the project. It is expressed as PN, if the nominal pressure is 1.6 MPa. Pipeline, note: “PN1.6MPa”, the nominal pressure can also be used as the dimension of kilopascal (KPa) and Pa (Pa). The conversion relationship is as follows: 1MPa=1000KPa=1000000Pa; the test pressure is for the strength and compressive performance of the pipeline. The pressure used for the test, the permanent Ps mark, in order to ensure the safe use of the pipeline, the test pressure requirement is higher than the nominal pressure; the working pressure refers to the pressure that the pipeline is subjected to in practical applications.

Petroleum pipeline connection and control

Connection and flange


The petroleum pipeline must use a certain link to form a complete system. Pipes are mainly connected by thread, welding and flange connection. The pressure is not high, and the pipe with small pipe diameter can be connected by the method of thread. This connection method is convenient, but since the diameter of most main petroleum pipelines is generally large, the other two connection methods are often used. Pipes with DN ≥ 50 are basically connected by welding. The welding has the advantages of convenient construction, firmness, strictness and steel saving. Generally, the parts that do not need to be disassembled in straight pipe or curved road can be used. Flange connections are made between pipes and valves or other equipment (eg pumps) and where the pipes need to be removed. To ensure the tightness of the flange joints, relatively soft flanges are required on both sides of the flange. The washer assists. Flanges can be divided into flat welding, threading, butt welding, loose sleeves and blind plates according to the production process. Except for blind flanges, they are used for connecting pipes. If you need to connect different diameters. For the pipeline, the diameter flanges corresponding to the two diameters can also be used. The blind flange is used for the closing of one end of the pipe head and is therefore designed to withstand large bending stresses.

Valve and control

ss valves 500x500 - What is a petroleum pipeline?

A valve is a mechanical device used to open, close, or control the flow of media within a pipe. There are many types of valves and there are many ways to classify them. If divided according to the purpose, it can be divided into cut-off valve, check valve, distribution valve, etc.; if divided by pressure can be divided into vacuum valve (working pressure is less than standard atmospheric pressure), low pressure valve (PN ≤ 1.6MPa), medium pressure valve (PN =2.5—6.4MPa) and high pressure valve (PN=10-80MPa). According to the driving method, it can be divided into manual valve, power driven valve and automatic valve, as well as different classification methods according to temperature or material. The gate valve is equal to the valve base and the valve plate. The valve plate moves vertically up and down with the valve stem through the hand wheel, thereby cutting or opening the pipe, and at the same time adjusting the opening ratio of the pipe. Due to the characteristics of the ram, the gate valve is mostly fully open or fully closed during normal application, and is less used for flow regulation, but the gate valve has the advantages of good sealing performance and convenient maintenance. The spool of the shut-off valve falls vertically on the base, the valve seat is parallel to the centerline of the pipeline, the fluid flows in the “S” shape in the valve body, and the fluid resistance is large. The shut-off valve is generally used for flow regulation, and has convenient manufacturing and maintenance. A little bit, but it is easy to leak when closed, and the sealing is not as good as the gate valve.
In the laying of long-distance pipelines, valves shall be installed along the line, and the spacing shall not exceed 32km. If the pipeline passes through sparsely populated areas, it may be appropriately relaxed. Valves shall be provided along the buried petroleum pipeline along the ends of pipelines that span large rivers, lakes, reservoirs, and densely populated areas such as towns or as deemed necessary by topographical conditions. The location of the shut-off valve shall be free from geological disasters and floods, and shall meet the needs of convenient transportation and convenient maintenance, and shall be provided with protective facilities.

Corrosion and corrosion protection of oil pipelines

Since the delivered oil contains sulfur and acidic substances, the exposed pipe is exposed to the wind and rain in the open air, which causes the pipe to be easily corroded. The main corrosion of pipelines is as follows: oxygen absorption corrosion of steel caused by the principle of primary battery; hydrogen evolution corrosion caused by acid sulfide (sulfur dioxide and hydrogen sulfide) on the surface of the pipeline due to acid rain; acid corrosion of carbon dioxide caused by atmospheric precipitation The surface of the pipeline is capable of metabolizing the bacteria caused by the bacteria of the sulfate and the corrosion caused by the water accumulated in the pipeline. Among them, the oxygen corrosion is the most corrosion, and the principle is as follows:

  • Under neutral conditions: O2 + 2H + 4e → 2OH
  • Under alkaline conditions: O2 + 2H2O + 4e → 4OH
  • Under acidic conditions: O2 + 4H + 4e → 2H2O

Because the causes and conditions of pipeline corrosion are not the same, pipeline corrosion protection has the following different methods according to different corrosion conditions: reasonable material selection, different types of materials are selected according to different transportation media and environmental conditions; cathodic protection is external DC The power source is protected by the fact that the pipe metal originally being the anode itself becomes a cathode, or a metal having a relatively more active chemical activity is attached to the pipe so that the two constitute a primary battery, and at this time, the more active metal is corroded. The pipe itself is protected; the medium treatment includes removing the corrosive components of the medium or adjusting the pH value; adding an anti-corrosion coating (such as paint) on the metal surface to isolate the steel pipe from the oxygen in the air, This achieves the protection effect; the addition of “corrosion inhibitor”, corrosion inhibitor is a special additive added to metal equipment for mitigating corrosion. It is an anti-corrosion technology for pipelines and other fields due to its small dosage, low investment and obvious effects. The key development direction, the corrosion prevention principle of corrosion inhibitor can be described as anti-catalysis, that is, and chemical industry students Instead catalyst principles used, corrosion inhibitor will increase the activation energy required for a chemical reaction, in order to slow down the rate of corrosion reaction occurs.

Oil pipeline layout

Common piping arrangements are as follows:

In the single pipe system, double pipe system, and independent pipeline system, the pipeline is laid. In order to reduce the resistance, the method of straight line laying is generally adopted. There are three types of ground, pipe ditch and underground. The pipes within the oil depot wall should be laid on the ground. The pipes that have been buried underground or the pipes that have been laid in the pipe trenches should be combined with the technical transformation of the oil depots, and should be gradually changed to the ground as much as possible, and the oil pipelines outside the fences should not interfere with traffic and occupy farmland. Generally, the pipeline is directly buried in the ground after being treated with anti-corrosion treatment, and the depth is 0.5~0.8m.

China’s oil pipeline

Built the earliest Chinese crude oil pipeline

The earliest crude oil pipeline built in China is the Karamay-Dushanzi crude oil pipeline, which is referred to as the ke-only crude oil pipeline. The pipeline is 147.2 kilometers long, with a diameter of 159 mm, a design pressure of 7.0 MPa, and a conveying capacity of 530,000 tons per year. It was completed and put into operation in January 1959.

The longest Chinese crude oil pipeline

The longest crude oil pipeline in China is the western crude oil pipeline. The pipeline starts at the first station of Wangjiagou in Urumqi and ends at the end station of Lanzhou. The trunk line is 1858 kilometers long, with a diameter of 813 mm, a design pressure of 8 MPa, and a designed transmission capacity of 20 million tons per year. It was completed and put into operation in June 2007.

China’s crude oil pipeline with the largest diameter

The crude oil pipeline with the largest diameter in China is the Rizhao-Yizheng crude oil pipeline. The pipeline starts from Rizhao, Shandong Province, south of Jiangsu Yizheng, with a length of 390 kilometers, a diameter of 914 mm, a design pressure of 8.5 MPa, a recent design transmission of 20 million tons/year, and a long-term design of oil transportation of 36 million tons/year. It was completed and put into operation on October 10, 2011, and the oil products imported were crude oil imported from the sea.

The world’s major oil pipelines

United States

The United States has a large amount of oil production, and because of its large consumption, it is also a major oil importing country. The development of the US refined oil pipeline has great significance. While constructing crude oil pipelines, the United States also attaches great importance to the construction scale and efficiency of refined oil pipelines.
In recent years, the US crude oil production level has been developing steadily, from 267 million tons in 1950 to 475 million tons in 1970. After that, the annual crude oil production is about 400 million tons. With the modernization process, the US oil consumption is also increasing, from 325 million tons in 1950 to 897 million tons in 2000. In this context, the refined oil pipeline has developed rapidly, and there are new kilometers of refined oil pipelines every year. By the 1980s, the length of refined oil pipelines has exceeded the length of crude oil pipelines.
The US refined oil pipeline is advanced, not only because of its long total length, but also because of the long distance and large diameter of the pipeline, and it has the characteristics of many oil inlet points and large oil delivery. Among the 100 liquid pipeline companies in the United States, there are 10 companies with an annual output of more than 25 million cubic meters. Among them, the single line was completed at the end of 1964, and the Coronil refined oil pipeline system was built in 1979. The total length is 8008 km, the maximum diameter is 1016 mm, and there is a long oil supply section. There are 5 oil input stations and 37 The sub-transmission station diverts to the branch line. The two-line pipeline system has an annual oil transportation capacity of 93 million tons, and can transport more than 100 kinds of various refined oil products in sequence, becoming the world’s largest refined oil transportation pipeline.


The total length of the French refined oil pipeline is 6,750 km. There are 4 large-scale oil product pipeline systems and a large number of local refined oil pipelines (about 20). The largest refined oil pipeline is the finished product of Trapière, which was put into operation in 1953. The oil pipeline system consists of 3 trunk lines and 13 branch lines with a total length of 1,330 kilometers and a total oil transportation capacity of 68 million tons per year. The system links 17 refineries in Leove and the Central Seine (58.5 million tons of crude oil per year) to distribution tanks and transfer tanks in the Paris, Normandy, Orleans and Tours regions.

United Kingdom

The first commercial oil pipeline in the UK was completed and put into operation in 1960. After the 1970s, the refined oil pipeline was developed. In 1979, the mileage of refined oil pipelines reached 1980 kilometers. After 1980, the transportation of refined oil pipelines further developed, and the structure of refined oil transportation changed. By 1986, pipelines accounted for 36%, highways accounted for 28%, and water transport accounted for 31%. The share has been ranked first.


Canadian oil pipelines are also well developed. In 1980, the length of the refined oil pipeline reached 4,800 kilometers, which was almost 1.5 times increased from the 1960s to the 1980s. The product tubing network runs from west to east across Canada’s industrially developed and densely populated areas. Canada’s largest refined oil pipeline is an inter-provincial pipeline with a length of more than 6,000 kilometers, a maximum diameter of 864 mm, and a delivery of up to 65 kinds of oil. The refined oil is exported to the United States in addition to the foreign supply.

Source: China Petroleum Pipeline Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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