Pigging practice in Yi-Chang Crude Oil Pipeline

Since Yi-Chang Crude Oil Pipeline put into production in May, 2006, the pigging for it had not been made until Sept. 2012. Then, in order to fundamentally improve the running condition of the pipeline, pigging was carried out twice. In the first pigging operation, YY-RGQ soft pig was used to decrease the risk of pigging and guarantee safe running. While in the second pigging operation, YY-JDQ pig with tracking equipment was used. This paper presents the pigging process including the operation of sending and receiving pigs and technical requirements of pigging. The result shows that in the first pigging, there were lots of impurities and less wax in the pipe section where heater was operating. In the second pigging, although the wax and impurities cleaned out were much less than that in the first time, the wax deposition had already affected the economical running of the pipeline, which indicates that the pigging interval is unreasonable. Therefore, it is suggested that heating transportation should be applied in the wax prone pipeline section to guarantee that the oil temperature is higher than the wax precipitation point and optimum interval of pigging should be figured out to make reasonable pigging plans accordingly.