Corrosion Analysis of G105-Coated Drill-Pipe Washout and Electroless Plating Ni-P as Drill-Pipe Protection in Freshwater Mud

• Published in: Corrosion (Houston, Tex.) Vol. 70; no. 6; pp. 652 - 659
• Main Authors: Lian, Zhouyang, Chen, Dongsheng, Wei, Wuji, Zhou, Yongzhang, Jiang, Juncheng
• Format: Journal Article
• Language: English
• Published: Houston, TX NACE International 01.06.2014
• Subjects: Abrasion; Abrasion resistance; Acidification; Analytical methods; Applied sciences; Coatings; Corrosion; Corrosion environments; Corrosion prevention; Corrosion products; Corrosion rate; Corrosion resistance; Crack propagation; Drill pipe; Drilling; Drills; Electroless plating; Electron microscopy; Exact sciences and technology; Fatigue failure; Freshwater; High temperature; Inland water environment; Manganese; Mechanical properties; Metal fatigue; Metallic coatings; Metallurgy; Metals. Metallurgy; Microscopy; Microstructure; Mud; Nickel; Nonmetallic coatings; Nucleation; Organic coatings; Phosphorus; Pitting (corrosion); Production techniques; Propagation; Protection; Scanning electron microscopy; Scientific imaging; Sorbite; Spectroscopy; Sulfide; Sulphides; Surface treatment; USA, Texas, Houston; organic coating; Nickel base alloys; Tube; Machining; Drill; Non metallic inclusion; Corrosion rate; Non metal coating; Surface treatment; Corrosion resistance; Pitting corrosion; Metal coating; pitting; Chemical deposition; Cutting tool; Microstructure; Protection; inclusions; Organic compounds
• ISSN: 0010-9312; 1938-159X
• DOI: 10.5006/1040

G105 (API SPEC 5D group 3)-coated drill pipes suffer from washout after drilling for 70,000 m to 80,000 m. The microstructure, micromorphology, and corrosion products near the washout were analyzed by metallurgical microscopy, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Electroless plating Ni-P as drill pipe protection in freshwater mud was studied. Results showed the metallographic microstructure of the material was typical tempered sorbite. No fatigue crack was observed. Drill-pipe washout was caused mainly by the inclusion of manganese sulfide (MnS) in steel because of the excess S and by damaged coating, both of which induced pit nucleation and promoted the pitting corrosion process. Electroless plating was cystiform in structure on the surface, and phosphorus content was 13.23%. which was high phosphorus and corrosion-resistant plating. Maximum corrosion rate of electroless plating was a quarter of the minimum of the corrosion rate of G105. Organic coating was damaged by enhanced abrasion after 10 h, and electroless plating did not change basically after 50 h. Organic coating bubbled after 10 h under low velocity because of high-temperature corrosion, but electroless plating had no change.