Experience and lessons in crude oil pipeline pigging: Case studies from field practices

Abstract

In flow assurance of crude oil pipeline transportation, pig stalling and wax blockage in pigging could cause complete shutdown of the whole pipe. In consequent wax remediation, thumb rules of the operators usually play a crucial role due to the lack of theoretical understanding of wax removal and accumulation mechanisms. Therefore, learning from previous wax remediation practices becomes necessary to avoid these accidents. In response, this paper extensively surveys multiple field pigging operations and summarizes the experience and lessons obtained from these incidents. Several typical scenarios such as long-unpigged pipe and back flow in pig rescue are investigated. Some puzzling phenomena where the pig moves in front of the wax plug and occurrence of wax blockage without pigging are also analyzed. The drawn experience and lessons could be helpful in scheduling pigging program and enhancing the security.

Keywords:

• Pig stalling
• pipeline pigging
• wax deposition
• wax blockage
• wax remediation

Additional information

Funding

This work was supported by National Natural Science Foundation of China (Grant No. 52104066) and Natural Science Foundation of Fujian Province, China (Grant No. 2020J05097).