MSc. project: Experimental study of by-pass pigging with speed control in a pipeline
A pipeline inspection gauge, or PIG, is commonly used for pipeline operations in the oil and gas
industry: it is typically a cylindrical object which is launched into the pipeline and travels through the
pipeline while being propelled by the production of fluids (gas and/or oil accompanied by possibly
some amount of water), see figure 1.
Pigging operations can have multiple purposes, e.g. cleaning the walls of the pipeline, removing
liquids from the pipeline (see figure 1), distributing corrosion inhibitors along the walls of the
pipeline, or inspection of the pipeline. Some pigs also have an opening, which allows a part of the
production fluids to by-pass the pig during the pigging operation, see figure 1b. These pigs are called
by-pass pigs, and it turns out that the flow behaviour around a by-pass pig can be quite different
from a conventional pig, which can be beneficial for an efficient pigging operation. For example,
when pigging a pipeline with a certain liquid holdup, the use of a by-pass pig can result into a holdup
slug with a larger length compared to a conventional pig without by-pass area, see figure 1a. The bypass
opening generally results in a lower travelling velocity of the pig. Care has to be taken when
using by-pass pigs because a too low pig velocity might result in a pig that gets stuck in the pipeline.
By-pass pigs can be equipped with speed control. This allows the speed of the pig to be controlled
during the pigging operation by adjusting the by-pass area, see figure 2 for an example of a by-pass
pig with speed control. Speed control can provide the optimum pig velocity, without running the risk
that the pig gets stuck. In addition, it has been shown that a speed controlled pig can result in better
inspection and better cleaning of the pipeline. All these advantages make that by-pass pigs with
speed control are of great interest for the oil and gas industry. The flow behaviour around a by-pass
pig with possible speed control in oil and gas pipelines is however not fully understood, and
experiments are needed to better predict its behaviour in a pipeline.
The objective of the project is to experimentally investigate the behaviour of a speed controlled bypass
pig in a pipeline system. Part of the assignment is to design a scaled down by-pass pig, with an
adjustable by-pass area in order to adjust the speed. The pig movement has to be studied in a
water/air loop facility at TU Delft. The pressure drop across the device needs to be measured.
Additional flow visualizations will provide insight in the two phase flow behaviour around the pig.
Experimental results will be compared with existing theoretical and numerical models.
For more information of the project please contact:
[1] A. Entaban, A. Ismail, M. Jambari, P. Ting, K.M. Amin, C.C. Ping, S. Zou, and G. van Spronsen. Bypass
pigging – a ‘simple’ technology with significant business impact. International Petroleum
Technology Conference [IPTC] (Being, China, 3/26-28/2013) Proceedings, 2013.
[2] N. Money, D. Cockfield, S. Mayo, and G. Smith. Dynamic speed control in high velocity pipelines,
2012. Pipeline and Gas Journal, August 2012.