Ultra-Thick Plating: Cost-Effective Alternative to Cladding and CRA for OCTG Coatings (C2026-00018)

lei zhao, Jiaxiang Ren, Peng Cheng, Ye Tian

Carbon steel with internal polymer coatings is widely used for corrosion protection in oil country tubular goods (OCTG). However, as operations move into harsher environments—high pressure, high temperature, and sour service—traditional coatings face limitations such as thermal degradation, blistering, and gas-induced failure. Emerging applications like CCUS and hydrogen injection further challenge these coatings due to rapid cycling and gas embrittlement.
To overcome these issues, a novel ultra-thick cobalt-based electroplating technology has been developed, providing uniform internal coatings up to 0.5 mm thick at a cost similar to high-end polymer coatings. This new process offers high hardness (>900 HV), excellent adhesion, fine surface finish (Ra ≈ 0.8 µm), and good ductility (~0.28% elongation). Extensive lab tests confirm strong resistance to corrosion, wear, and erosion in aggressive downhole environments, including supercritical CO₂ and sour brines. The coatings have passed NACE MR0175 SSC and other ASTM evaluations, with field trials showing excellent performance and reduced friction during operations.
This technology delivers a step-change in OCTG protection, providing a cost-effective alternative where polymer coatings fail and solid CRA is too expensive. Its potential spans oil and gas, geothermal, hydrogen, CCUS, aerospace, and chemical sectors.