The Scouring of Oil and Gas Pipelines

In recent years, as China attaches great importance to the process of urbanization, the speed of urbanization in China has accelerated significantly. At the same time, China's pipeline transportation industry is also booming. More and more dangerous source pipelines are gradually approaching people's living areas due to the rapid development of the urbanization process, which has also brought great safety hazards to people's daily life; in addition, some industrial raw materials and products in industrial production are dangerous. Although the factories producing these products are far away from residential areas, the urban gas pipelines and natural gas pipelines surrounding them also pose a great safety hazard.
 
1.1 Research background and significance
The rapid development of the global economy is inseparable from the massive consumption of energy. In the beginning, energy sources such as coal and oil were widely used, which brought serious air pollution, so environmental issues gradually attracted people's attention. To solve this problem, people call for the development and use of clean energy. Among them, the most widely used clean energy is natural gas, which has been applied to all walks of life. The pipeline transportation industry has also developed rapidly with the substantial increase in natural gas consumption in China. According to relevant data, some experts predict that the consumption of natural gas in China will reach 300 billion cubic meters by 2020; by the end of 2016, the total mileage of oil and gas pipelines in China has reached 116,400 kilometers, including 68,000 kilometers of natural gas pipelines; in 2017 In July, the National Energy Administration mentioned in the "Medium and Long-term Oil and Gas Pipeline Planning" that the scale of China's oil and gas pipeline will reach 240,000 kilometers in 2025.
 
With its advantages of large capacity, simple structure, energy saving and high efficiency, pipeline transportation has become the fifth mode of transportation after road, railway, aviation and water transportation. Pipeline transportation has greatly promoted the development of the oil and gas industry and the growth of the world economy Especially in the long-distance transportation of bulk materials. With the continuous increase in the mileage of the transportation pipeline and the continuous accumulation of its use time, the failure of the transportation pipeline also begins to occur frequently. Therefore, the causes of pipeline leakage have gradually become a research topic for many scientific researchers in recent years.
 
Among them, some scholars said that during the transportation of oil and gas pipelines, small solid particles mixed in the fluid medium will have an impact on the pipe wall. Although the impact of small particles on the pipeline seems to be little in a short time, the cumulative effect over time will cause great damage to the pipe wall. The reason is that these small solid particles scour and damage the pipe wall for a long time, causing leakages in pipelines and forming a major accident. According to the statistics of EGIG in 2015, the failure of pipelines from 2004 to 2013 is shown in Figure 1. The proportion of damage to pipelines caused by erosion and corrosion is as high as 24%. The proportion of accidents caused by corrosion and erosion ranks second after the investigation and analysis of 1123 accidents in pipelines, only next to external interference factors.
 
The reason why scouring often occurs in the process of oil and gas pipeline transportation is that the fluid inevitably carries some small solid particles, such as sand, stone and metal debris in the pipeline transportation process, and there will be impact, friction and cutting of these small particles on the pipe wall, making the thickness of the partial pipe wall thinner, and even damaging the pipe, which will lead to a reduction in the service life of the pipe and cause major harm to the surrounding environment and people. Corrosion caused by scouring will more easily lead to thinning or perforation of the pipe wall structure, especially when the fluid is a two-phase flow or multi-phase flow, such as the presence of solid particles in the liquid phase flow, forming the so-called liquid-solid two-phase flow.
 
Scouring mostly occurs in gathering and transportation pipelines. According to survey data, 80% of pipeline perforations are caused by the scouring of pipelines. Elbows, tees, valves and other components are the concentrated parts where scouring occurs. Studies have shown that the incidence of straight pipe erosion is only 2% of the incidence of elbows, because they have a more complex structure than the straight pipe. The main function of the elbow in the pipeline is to change the direction of the transportation pipeline. When it changes the flow direction of the medium in the pipe, it further promotes the friction and collision of the flowing medium in the pipe, and aggravates the formation of scouring; the main function of the tee in the pipeline is to guide the diversion or confluence of the fluid medium in the pipe. The same as the formation mechanism of the elbow scouring, the tee causes a great disturbance in the fluid in the pipe during the diversion or confluence process, and further aggravates the scouring. Among them, the Dina gas field in China leaked caused by the perforation of the tee. Therefore, it is of great significance to study the reliability and safety of elbows, tees and other parts for the safe operation of pipelines.
 
In addition, studying the leakage of pipe fittings caused by scouring in pressure pipelines can not only prolong the service life of the equipment but also reduce the economic losses caused by pipeline damage by predicting the leakage location and taking corresponding measures in time. Therefore, it is of great economic and social significance to study the internal scouring of pipelines to ensure the safe operation of pipelines and prevent accidents.

 

Send your message to this supplier


XIAMEN LANDEE INDUSTRIES CO., LTD.

XIAMEN LANDEE INDUSTRIES CO., LTD.


Source: https://www.landeepipe.com/the-scouring-of-oil-and-gas-pipelines.html