New Method to Determine the Strength of Wax Deposits in Field Pipelines

Chengyu BAI, Jinjun ZHANG


Mechanical pigs are generally used to remove the wax deposit in oil pipelines. A better understanding of the deposit strength is beneficial to make a suitable pigging schedule, preventing the pig from blocking. The previous studies mainly examined the effect of the operating conditions on the thickness and wax content of wax deposit. However, there was little work on the deposit strength, especially the field-deposit strength. This study focuses on a new method to determine the strength of wax deposit in field pipeline. First, the structure of wax deposit obtained from field pipelines and wax deposit formed in laboratory was observed. The results showed that the structure of the field wax deposits is much looser than that of wax deposit formed in lab. The looser structure could result in lower strength. Second, according to analyze, three basic factors contributing to the deposit strength are solid wax content, deposit structure and morphology of wax crystals. Based on above analyzation, a method by preparing model wax-oil gels in the lab instead of field deposit was proposed to measure the field deposit strength indirectly. The model gels were prepared by using the oil obtained from pipeline and a wax. As the structure of field deposit is looser than that of the model gels, a wax was chose to form the smaller size of wax crystals in model gels than that of wax crystals in field deposit for approximately the same strength between field deposit and model gels at the same solid wax content. The strength was measured by using the vane, and the solid wax content was determined by using differential scanning calorimetry (DSC). Third, the accuracy of new method was evaluated. Verification experiments showed that the new method is an effective method for determining the strength of field deposit.


New method; Wax deposit; Strength; Field pipeline

Full Text:



[1] Venkatesan, R. (2004). The deposition and rheology of organic gel (Doctoral dissertation). University of Michigan, Ann Arbor, Michigan.

[2] Wang, Q., Sarica, C., & Volk, M. (2008). An experimental study on wax removal in pipes with oil flow. J. Energy Resour. Technol., 130, 0430011-0430015.

[3] Mendes, P. R. S., Braga, A. M. B., & Azevedo, L. F. A. (1999). Resistive force of wax deposits during pigging operations. Journal of Energy Resources Technology, 121(3), 167-171.

[4] Creek, J. L., Lund, H. J., & Brill, J. P. (1999). Wax deposition in single phase flow. Fluid Phase Equilibria, 158-160, 801-811.

[5] Singh, P., Venkatesan, R., & Fogler, H. S. (2000). Formation and aging of incipient thin film wax-oil gels. AIChE Journal, 46(5), 1059-1074.

[6] Jennings, D. W., & Weispfennig, K. (2005). Effects of shear and temperature on wax deposition: Coldfinger investigation with a gulf of Mexico crude oil. Energy & Fuels, 19(4), 1376-1386.

[7] Banki, R., Hoteit, H., & Firoozabadi, A. (2008). Mathematical formulation and numerical modeling of wax deposition in pipelines from enthalpy-porosity approach and irreversible thermodynamics. International Journal of Heat and Mass Transfer, 51(13-14), 3387-3398.

[8] Singh, P., Venkatesan, R., & Fogler, H. S. (2001). Morphological evolution of thick wax deposits during aging. AIChE Journal, 47(1), 6-18.

[9] Hernandez, O. C. (2002). Investigation of single-phase paraffin deposition characteristics (Master dissertation). University of Tulsa, Tulsa, Oklahoma.

[10] Tiwary, R., & Mehrotra, A. K. (2009). Deposition from wax-solvent mixtures under turbulent flow: Effects of shear rate and time on deposit properties. Energy & Fuels, 23(3), 1299-1310.

[11] Brown, T. S., Nielsen, V. G., & Erickson, D. D. (1995). Measurement and prediction of the kinetics of paraffin deposition. Journal of Petroleum Technology, 47(4), 328-329.

[12] Bai, C., & Zhang, J. (2013). Thermal, macroscopic and microscopic characteristics of wax deposits in field pipelines. Energy & Fuels, 27(2), 752-759.

[13] Liddel, P. V., & Boger, D. V. (1996). Yield stress measurements with the vane. J. Non-Newtonian Fluid Mech., 63, 235-261.

[14] Léoffé, J. M., Claudy, P., & Kok, M.V. (1995). Crude oils: Characterization of waxes precipitated on cooling by d.s.c. and thermomicroscopy. Fuel, 74, 810-817.

[15] Li, H., Huang, Q., & Zhang, F. (2003). Determination of wax content in crude oil using differential scanning calorimetry. Shiyou Daxue Xuebao, 27, 60-62.

[16] Yi, S., & Zhang, J. (2011). Relationship between waxy crude oil composition and change in the morphology and structure of wax crystals induced by pour-point-depressant beneficiation. Energy Fuels, 25, 1686-1696.

[17] Li, H., & Zhang, J. (2003). A generalized model for predicting non-Newtonian viscosity of waxy crudes as a function of temperature and precipitated wax. Fuel, 82, 1387-1397.

[18] Juyal, P., Cao, T., & Yen, A. (2011). Study of live oil wax precipitation with high-pressure micro-differential scanning calorimetry. Energy Fuels, 25, 568-572.

[19] Bai, C., & Zhang, J. (2013). Effect of carbon number distribution of wax on the yield stress of waxy oil gels. Ind. Eng. Chem. Res., 52(7), 2732-2739.

[20] Lee, H. S. (2008). Computational and rheological study of wax deposition and gelation in subsea pipelines (Doctoral dissertation). University of Michigan, Ann Arbor, Michigan.



  • There are currently no refbacks.

Copyright (c) 2015 Advances in Petroleum Exploration and Development

Share us to:   


  • How to do online submission to another Journal?
  • If you have already registered in Journal A, then how can you submit another article to Journal B? It takes two steps to make it happen:

1. Register yourself in Journal B as an Author

  • Find the journal you want to submit to in CATEGORIES, click on “VIEW JOURNAL”, “Online Submissions”, “GO TO LOGIN” and “Edit My Profile”. Check “Author” on the “Edit Profile” page, then “Save”.

2. Submission

  • Go to “User Home”, and click on “Author” under the name of Journal B. You may start a New Submission by clicking on “CLICK HERE”.

We only use three mailboxes as follows to deal with issues about paper acceptance, payment and submission of electronic versions of our journals to databases:;;

 Articles published in Advances in Petroleum Exploration and Development are licensed under Creative Commons Attribution 4.0 (CC-BY)


Address:1020 Bouvier Street, Suite 400, Quebec City, Quebec, G2K 0K9, Canada.

Telephone: 1-514-558 6138
Website: Http://

Copyright © 2010 Canadian Research & Development Centre of Sciences and Cultures