Due to the high temperature, high pressure and sophisticated chemical environment in heavy oil wells, Steam-Assisted Gravity Drainage (SAGD) is considered one of the most challenging service conditions for carbon steel equipment. This paper introduces an advanced metal-metal bonded coating technology-electroless nickel (EN) coating and its applications in SAGD operations to protect downhole equipment from fouling due to corrosion, adhesion of inorganic and organic materials as well as the impacts of wettability alteration. In the first chapter, we will describe the complex and hostile thermal-chemical environment, their impacts on the SAGD production system and the fouling causes. We will compare the performance of EN coating to that of regular carbon steel pipe in the following aspects: a) corrosion resistance in the presence of sour gases using potentiostatic and potentiodynamic polarization methods; b) adhesion of silica, bitumen coated silica using atomic force microscopy, and c) surface energy and wettability alteration using contact angle measurements. The set-up of the facility, procedures of the tests and governing science and engineering principles will be reviewed. In the end, we will introduce the results of laboratory and SAGD field experiments designed to investigate the EN coating technology in protecting the substrate materials under SAGD conditions.

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