Volume 8, Issue 6 1901412
Review

Advances and Future Challenges of Wax Removal in Pipeline Pigging Operations on Crude Oil Transportation Systems

Weidong Li

Weidong Li

College of Chemical Engineering, Fuzhou University, No. 2 Xueyuan Road, University Town, 350116 Fuzhou, China

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Qiyu Huang

Corresponding Author

Qiyu Huang

National Engineering Laboratory for Pipeline Safety/Beijing Key Laboratory of Urban Oil and Gas Distribution Technology, China University of Petroleum-Beijing, No. 18 Fuxue Road, Changping District, 102249 Beijing, China

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Wenda Wang

Wenda Wang

PetroChina Marketing Company, No. 9 Dongzhimen North Street, Dongcheng District, 100007 Beijing, China

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Xuedong Gao

Xuedong Gao

National Engineering Laboratory for Pipeline Safety/Beijing Key Laboratory of Urban Oil and Gas Distribution Technology, China University of Petroleum-Beijing, No. 18 Fuxue Road, Changping District, 102249 Beijing, China

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First published: 13 March 2020
Citations: 31

Abstract

Wax deposition is a severe flow assurance challenge that threatens waxy crude oil production and transportation. For wax remediation, pipeline pigging is the most widely used technique. However, the elusiveness of wax removal mechanism and the lack of reliable methods to evaluate wax breaking force and wax removal efficiency easily trigger pig stalling and wax blockage in field pigging operations. Modeling wax breaking force and wax removal efficiency, therefore, promotes the pigging confidence. This Review seeks to clarify the current picture of wax removal research in crude oil pipeline pigging. Relevant wax deposit properties including wax layer thickness and strength are discussed. Wax removal mechanisms are summarized from perspectives of wax–pig interaction, macroscopic force response, and scenarios with oil flow. Prediction models of wax breaking force and wax removal efficiency are analyzed comprehensively. Pig geometry optimization using this model is given. In addition, the key roles of wax deposit strength, viscoelasticity and thixotropy, foam pig investigation, and wax plug prediction are highlighted for guiding future endeavors in this area.

Conflict of Interest

The authors declare no conflict of interest.

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