Ⅰ. Definition of pipeline transportation
Pipe transport is a means of transporting liquid, gas or semi-solid material through a pipe. This mode of transportation uses a large pipe system, usually made of metal or plastic, to connect the distance between the supply station and the end user. Pipeline transportation can be used for many different applications, including oil, gas, water, chemicals, and other types of fluid transportation. In some applications, pipeline transportation can provide an efficient, fast, and safe means of delivery while reducing environmental impact and costs.

Ⅱ. Pipeline transportation can be classified according to the transportation method of liquid, gas or semi-solid material. According to the different media, pipeline transportation can be divided into the following categories:
Oil pipelines: Used to transport liquid oil products such as crude oil and petroleum products to storage tanks, refineries and end users.
Gas pipeline: used to transport gas and other gaseous fuels to cities, factories, fertilizer plants and other places to supply heat and fuel.
Water pipeline: used to transport clean water, sewage and other water resources to urban, rural and other places to supply residents with drinking, production and irrigation.
Chemical pipelines: Used to transport dangerous goods such as chemicals and liquefied gas to chemical plants, industrial fields and end users.
Other types: In addition, there are also some special purpose pipes, such as conveying powder, semi-solid materials pipeline system.

Ⅲ.  Advantages of pipeline transportation industry
1. High safety: pipeline transportation facilities and maintenance are highly regulated, and independent pipeline systems are not susceptible to external influences. In contrast, other modes of transport, such as roads and railways, are more susceptible to accidents or bad weather.
2. Good environmental protection: pipeline transportation can reduce greenhouse gas emissions and noise pollution. In contrast, other modes of transport such as cars, planes, etc., produce more exhaust gases and noise, causing a greater burden on the environment.
3. High transportation efficiency: pipeline transportation is fast and can transport a large number of materials in a short time, compared with other modes of transportation may take longer to complete the same amount of goods transportation.
4. Low operating costs: because the pipeline investment is relatively high, but the operating cost of pipeline transportation is relatively low, a construction can be used for a long time, saving human and material resources.
5. Long distance transport: pipeline transport is suitable for long distance or multi-node transport. In contrast, other modes of transport require transit points, adding steps to transport as well as costs.

Ⅵ. Pipeline transportation development history
Pipeline transportation as an efficient, safe and environmentally friendly mode of transportation, its development can be traced back to 3000 BC in India and China. Ancient India and China used materials such as bamboo and copper pipes to build ditches and waterways to transport water and irrigate farmland in the early days. The construction of water and sewage pipes also began in the Greek and Roman periods. In the late 18th and early 19th centuries, with the rapid development of coal, railways and industrialization, people began to use pipe systems made of wood and cast iron to transport gas and water.
At the beginning of the 20th century, North America began to use advanced technologies such as steel pipes and welding technology to establish large-scale natural gas transmission pipelines, thus meeting the needs of industrial and urban gas. Since then, pipeline transportation has continued to develop and expand, and the scope of application has gradually expanded. With the development of science and technology, the use of new materials such as polymer materials and composite materials makes pipeline transportation safer, more efficient and environmentally friendly. At present, pipeline transportation has become an important mode of energy and materials transportation, and it is developing and growing.

Ⅴ. Pipeline transportation industry chain
Upstream refers to the exploitation and production of oil, natural gas and other energy resources, also known as exploration and development. In the upstream link, it mainly includes exploration, development, production and treatment processes. Midstream refers to the transportation of energy resources such as crude oil and natural gas from the collection point to the processing site or transfer station. The midstream link usually consists of transportation facilities such as pipelines and ships. Downstream refers to refining, chemical, heating and other consumption links, in this stage, the need to convert crude oil, natural gas and other energy resources into more kinds of products such as gasoline, diesel and basic chemicals.

Ⅵ. Scale of pipeline transportation industry
By the end of 2020, the total length of global crude oil pipelines exceeds 950,000 km. In the global crude oil delivery volume, crude oil pipelines in the United States and Canada dominate, followed by the Middle East; The total length of natural gas pipelines in the world is more than 500,000 kilometers. Countries such as Russia, China, the United States and Canada have large gas pipeline systems; The total length of petrochemical pipelines in the world exceeds 500,000 km. North America and Europe are the largest petrochemical pipeline markets in the world, accounting for more than 70% of the global market share. The total length of the world's water pipeline is more than 200,000 kilometers. Europe and North America are leading the way in water pipeline construction. Liquefied natural gas pipeline is a new type of pipeline in recent years. At present, the total length of LNG pipelines in the world is about 100,000 kilometers. Countries such as Australia, Qatar and the United States are among the world's largest LNG producers and have large LNG pipeline systems.
The total value of China's pipeline transportation industry in 2020 is 1.70 trillion yuan (about 260 billion US dollars). Among them, oil and gas pipeline transportation is the main field, occupying the vast majority of the market share, and continues to develop steadily. As the pipeline transportation industry belongs to the infrastructure industry, its profitability is relatively low, but on a stable and reliable basis, it can provide long-term stable cash flow. Therefore, pipeline transportation companies tend to have strong asset values and are considered to be one of the sound choices in the investment field.
1.17-22 Chart of market size data:
Statistics show that in 2017, the market size of China's pipeline transportation industry was 1.47 trillion, and in 2022, the market size of China's pipeline transportation industry was 1.96 trillion. The market size of China's pipeline transportation industry from 2017 to 2022 is as follows:
2. Chart of 23-29 market size data
It is predicted that the market size of China's pipeline transportation industry will reach 6.34 trillion yuan in 2029. The market size forecast of China's pipeline transportation industry in 2023-2029 is as follows:
The market share of China's pipeline transportation enterprises is mainly concentrated in China National Petroleum Corporation, Sinopec, CNOOC, China Huaneng Group, etc., which has a wide pipeline network and rich experience, and has a high R & D level and technical strength in pipeline transportation technology.

Ⅶ. Policies related to the pipeline transportation industry
The Chinese government has issued a series of supporting policies related to pipeline transportation to promote the healthy development of the pipeline transportation industry. "Opinions on Strengthening the Construction of Oil and Gas Pipeline Network" proposed to accelerate the construction of pipeline networks in key regions, optimize pipeline layout, improve peak load capacity, and improve supply security capacity. The Implementation Opinions on Accelerating the Construction and Utilization of Natural Gas Infrastructure strengthen the investment and management of natural gas pipelines, improve the natural gas reserve system, accelerate the construction of natural gas terminal markets, and promote the upgrading of natural gas consumption. The Notice of the General Office of the Ministry of Water Resources on Strengthening the Safety Management of water pipelines proposes to strengthen the supervision and management of water pipelines, establish a sound safety management system, strengthen risk prevention and control measures, and ensure the safe operation of water pipelines. The Opinions on Accelerating the Structural Adjustment of the Petroleum and Chemical Industry propose to promote the structural adjustment of the petroleum and chemical industry and improve the technical level and competitiveness of the industry by promoting pipeline transportation, developing new materials, and improving the efficiency of resource utilization.

Ⅷ. Development obstacles and challenges of pipeline transportation
1. Insufficient capital investment: Pipeline transportation construction requires a large amount of capital investment, but due to the long investment return cycle, as well as fierce market competition and other reasons, a considerable part of private capital may choose other more attractive industries to invest.
2. Imperfect management and supervision system: In the field of pipeline transportation, the perfection of management and supervision links plays a crucial role in the safety and reliability of the entire industrial chain. However, because pipeline transportation involves the coordination and management of many departments, its supervision and standardization still have a large room for improvement.
3. Lack of technological innovation: the current pipeline transportation technology has been very mature, but compared with other fields, the speed of technological innovation is slower, especially in the pipeline materials, sensor technology and other aspects of the research still need to be strengthened.
4. Increasing environmental pressure: the impact of pipeline transportation on the environment can not be ignored, especially the leakage of oil and gas pipelines may cause pollution to ground and groundwater resources, bringing risks to the ecological environment.
5. External factors interference: Pipeline transportation is also affected by external factors such as policy, geographical and international markets, such as international trade disputes, political conflicts and natural disasters.

Ⅸ. With the increasing global energy demand and the increasingly stringent requirements of various countries for environmental protection, the development prospects of pipeline transport are still broad.
1. The natural gas market potential is huge: in China, the medium - and long-term natural gas development plan proposes that natural gas consumption will account for 10% of total primary energy consumption by 2020, and will reach 15% by 2035. Globally, due to the increasing demand for clean energy and the increasing use of alternative fuels, the natural gas pipeline transportation market is expected to witness further growth.
2. Increasing demand for remote water resources transportation: With the continuous advancement of urbanization, the shortage of water resources has become one of the main problems facing urban development. In desert or mountainous areas with abundant water resources, water resources need to be deployed across regions through pipeline transportation technology, which also brings new opportunities to the pipeline transportation industry.
3. The application of new materials, sensor technology, etc. : New materials and sensor technology in the field of pipeline transportation can effectively improve the safety and reliability of pipelines, as well as reduce the maintenance and operating costs of pipelines. For example, nanotechnology can effectively improve the strength and corrosion resistance of pipeline materials.
4. National Policy support: The Chinese government has made natural gas one of the clean energy sources with the highest priority, and has formulated a series of policy measures to strengthen the planning and management of the gas industry. In addition, there are more and more countries or regions in the world regard the pipeline transportation industry as one of the important parts of infrastructure, and are willing to provide long-term stable financial support.
In summary, the pipeline transportation industry still has a broad space for development in the future. However, in the development of market prospects, it is necessary to take into account environmental protection, resource development efficiency, policy support and other factors to achieve sustainable development.