ABSTRACT

Oil and gas assets including tubing and piping are constantly exposed to corrosive elements that threaten their integrity and the safety of the surrounded environment. Corrosion and erosion damage mechanisms might lead to expensive repairs and operational downtime which ended to deploy expensive corrosion resistant alloys as part of the implemented corrosion management program. Among the available options to enhance materials integrity on cost effective manner is to leverage advanced material coatings in generating products with material property exceeding conventional corrosion resistant alloys.

Nanoceramic silicate and tungsten chemical vapor deposition thin film coatings were investigated and assessed against conventional clad weld-overlay (CWOL) Inconel Alloy 625 (N06625). The testing program covered advanced characterization for the applied films as deposited (SEM, TEM, XRD), physical and mechanical properties, dry erosion testing, and autoclave acid immersion testing.

The immersion testing scope addressed only sweet gas condition. Furthermore, the implemented laboratory testing program resulted in differentiation and ranking of the studied materials. Tungsten Coating showed strong potential to replace N06625 CWOL materials selection option under the tested conditions. For extreme erosion conditions, the coating thickness should be increased. Moreover, the nanoceramic silicate film exhibited brittle behavior which resulted failing the bending test.

INTRODUCTION

The oil and gas industry have constantly been striving to improve efficiency and reduce costs. Advanced materials and their enhancement were one of the strategies to achieving the aforementioned goals. These materials are specifically designed to withstand harsh corrosive conditions and sustain production capability over an extended period of time. There's a number of ways to enhance material integrity of sweet gas wells, including using CRAs, chemical treatment, monitoring wellbore environment and properly maintaining wellbore components.1

Carbon steels are widely used in oil and gas exploration and production service. However, these materials are prone to corrosion and cracking due to several reasons, including gas composition, temperature and pressure of wellbore and moisture.2 Oil and gas industries have adapted weld overlay cladding to manage the associated operational cost. Recent development of metallic coatings and their applications' methodologies have resulted in enhancing their corrosion resistance in highly corrosive and erosive environments. Cost reduction can be attained if these materials are coated by an industrial method, such as weld cladding, onto carbon steel.

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