The Pig Gravity Impact on Its Frictional Force in Oil and Gas Pipeline
- Xiaoxiao Zhu (China University of Petroleum) | Wei Wang (China University of Petroleum) | Shimin Zhang (China University of Petroleum) | Chuan Wang (Southwest Petroleum University)
- Document ID
- International Society of Offshore and Polar Engineers
- The 27th International Ocean and Polar Engineering Conference, 25-30 June, San Francisco, California, USA
- Publication Date
- Document Type
- Conference Paper
- 2017. International Society of Offshore and Polar Engineers
- gravity, frictional force, Pipeline pigging, stress distribution
- 1 in the last 30 days
- 56 since 2007
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The effect of the pig gravity on its frictional force was experimentally investigated. The stress distribution of the sealing disc in circumferential and radial direction with the variation of different pig gravities were revealed according to the finite element simulation. Research results indicated that the pig gravity almost has no effect on the frictional force of a pig, since the increased contact force in the lower part of the disc can offset the decreased force in the upper part. The stress distribution of the sealing disc in radial direction indicated that the maximum stress existed at the clamping edge.
Fossil fuels have been serving as the source of energy for almost all practical purpose of human existence, and they are of great importance to the development of the human beings. Fossil energy industry has used pipelines as the most economic, efficient and safe way to deliver oil and gas to terminals (Lesani, Rafeeyan and Sohankar, 2012). In order to maintain a good condition of these pipelines, pipeline inspection gauges (pigs) are periodical used to perform functions such as dewatering, cleaning, inspecting and et.al., and it has become a standard industry procedure now (Botros and Golshan, 2009). Pigs can achieve most efficiency when they run at a near constant speed but will not be effective in case that they run at very high speed. Moreover, excessive and uncontrolled pigging speed can be very dangerous, and often involves various risks such as get stuck in the pipeline or crash with pipeline accessories, especially in gas pipeline (Esmaeilzadeh, Mowla and Asemani, 2009). As a result, prediction on the pig motion to estimate its velocity, position and required driving pressure is particularly important before pigging. Accurate pigging prediction can even help to identify the potential risks and establish risk mitigation strategies (Zhu, Zhang, Li, Wang and Yu, 2015).
The frictional resistance between the pig and the pipeline plays an important role on determining the motion of a pig, and can greatly affect the accuracy of predicted results. Knowledge on the frictional resistance resulted from the soft contact between rubber (sealing disc or cup) and rigid pipe wall is of great importance for the understanding of pigging motion (Tan, Wang, Liu and Zhang, 2014).
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