Research on the Pigging Period Model for the Wax Crude Oil Transportation Pipeline Based on the Transportation Efficiency

Author of the article:Li Xunji1, Meng Bo1, Chang Zeliang1, An Chao1, Fang Yan1, Weng Weiqiang2

Author's Workplace：1. PetroChina Tarim Oilfield Company,； 2.School of Petroleum Engineering, Southwest Petroleum University

Key Words： Wax crude oil；Pipeline；Transportation efficiency；Pigging period；Mathematical model

Abstract：The wax often deposits on the inner wall of the pipeline when the oil temperature drops below the wax precipitation temperature of the oil, which decreases the transportation efficiency.Regular pigging is an efficient way to remove the deposited wax and to enhance the pipeline’s transportation efficiency.In order to make a safety and economic pigging period, a new mathematical model was proposed to describe the relationship between the pigging period, the transportation efficiency, and the wax deposition rate based on the definition of the transportation efficiency, and the wax deposition rate prediction method.The critical transportation efficiency used to determine the pigging period was also proposed.The Yingmali-Yaha oil pipeline of Tarim oilfield was taken as an example to validate the method. Results show that the pigging period for this pipeline is 110 days. Achievements of this paper provide a practical way to determine the reasonable pigging period for wax crude oil pipelines.