A Critical Review of the Modeling of Wax Deposition Mechanisms

Abstract

Deposition of high molecular weight paraffins on the inner wall of subsea production and transportation pipelines continues to be a critical operational problem faced by the petroleum industry. The accumulation of the deposited material on the inner wall of the lines may lead to increased pumping power, decreased flow rate or even to the total blockage of the line, with loss of production and capital investment. The present paper presents a critical review of the research effort devoted to the understanding and modeling of the basic deposition mechanisms that control the wax deposition processes. Molecular diffusion of paraffin has been identified as the dominant deposition mechanism. Most deposition models available in the literature make use of molecular diffusion as the sole mechanism for predicting spatial and temporal distributions of paraffin deposits. However, the study of the literature conducted in the present paper evealed that there is not enough experimental evidence to support this assumption. Other deposition mechanisms, such as Brownian diffusion of solid wax crystals may also play a role.

Acknowledgments

The authors gratefully acknowledge the support awarded to this research by the PETROBRAS R&D Center and by CTPETRO, the Petroleum Research Fund of the Ministry of Science and Technology of the Brazilian Government.