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Smooth operator
First operational pigging of the Changbei north trunk pipeline in China.
Doing something for the first time is not always easy or straightforward. And the first cleaning operation on a relatively new pipeline is no exception. Shell China Exploration and Production Company (SCEPCo) operates the Changbei north trunk pipeline. This 24-in., 23.5-km-long onshore, multiphase pipeline runs from Xiao Ji Han to central processing facilities in Yulin, and came into service in March 2007.
SCEPCo faced several challenges before conducting the first operational pigging: the low flow rate at the pipeline inlet meant that there was a large liquid holdup in the initial sections; the liquid handling capacity at the central processing facilities was restricted to 20 m3/h; and no slug catcher was installed.
With no previous maintenance history to guide the operation, and uncertainty about the pipeline’s condition (the amount of mud from the wells that might have settled in the pipeline) and the facility’s readiness for the operation, SCEPCo asked Shell Global Solutions for technical support.
The main risks identified were that the pig would stall or stick because of debris, and that the central processing facilities would not cope with the large liquid surge and would flood, either of which could disrupt gas supply to customers.