M. Fátima B. Sousa 1*, Celso A. Bertran 1, M. O. Penna 2 1 Department of Physical Chemistry, Chemistry Institute, University of Campinas, SP – Brazil 2 CENPES – Petrobras, Rio de Janeiro, RJ – Brazil P E T R O B R A S

Intoduction Experimental Setup Results Conclusion

Why inorganic scale forms on the surface of equipment used in oil extraction?  precipitation reactions from ions present in the formation water. Scale formation depends on the characteristics of the interface solid surface/scaling brine? P E T R O B R A S Introduction

 Is wettability important?  Surface free energy (SFE) and critical surface energy (CSE) are determined from wetting data.  Polymer coatings allows modulating wettability and can contribute to mitigate the formation of scale [1]. P E T R O B R A S Introduction 1 N. H. Lin, W-Y. Shih. E. Lyster, Y. Cohen, Crystallization of calcium sulfate on polymeric surfaces, J. Colloid Interface Sci. 356 (2011)

CSE and SFE were determined for several polymer coatings from different suppliers:  six epoxy phenol novolac (EPNs)  one fluoropolymer (FPA) resins, For evaluation of their anti fouling capacity when exposed to brines reproducing formation water from pre salt wells. *Stainless steel (SS) was used as reference. P E T R O B R A S Objective

Scaling Tests Contact angle measurements SEM analysis ICP analysis P E T R O B R A S Experimental Setup

P E T R O B R A S Critical Surface Energy - CSE negative value Zisman type graph:

P E T R O B R A S Surface Free Energy - SFE Test liquid Water Ethylene glycol For water: For ethylene glycol: Fowkes equation: measured contact angles

P E T R O B R A S Surface Free Energy - SFE

P E T R O B R A S SEM x 100

P E T R O B R A S SEM x 10k SEM x 2k

SEM x 10k

P E T R O B R A S Surface Free Energy - SFE

P E T R O B R A S SFE - ICP

Teflon-based coating FPA is the most hydrophobic and consequently presented lowest values for ECS and SFE. In general, considering the results of ICP and SEM, there are two groups of coatings. For the same manufacturer, coatings with lower SFE polar component presented less scale deposition. Coatings with macroscopically rougher surface presented higher scale deposition. P E T R O B R A S Conclusions

1 W. A. Zisman, “Contact Angle, Wettability and Adhesion,” Adv. Chem. Ser., 43,The American Chemical Society, Washington D.C., 1964, p 1. 2 N. H. Lin, W-Y. Shih. E. Lyster, Y. Cohen, Crystallization of calcium sulfate on polymeric surfaces, J. Colloid Interface Sci. 356 (2011) S. Siboni, C. Della Volpe, D. Maniglio, M. Brugnara, The solid surface free energy calculation II, J. Colloid Interface Sci. 271(2004) P E T R O B R A S

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