Perpustakaan Digital ITB

Carbon steel tubing operating in CO? rich production environments is susceptible to sweet corrosion, which reduces wall thickness and compromises mechanical integrity. This study evaluates the CO? corrosion rate and mechanical integrity of API 5CT Grade L80 tubing (OD 4.5 in, nominal wall thickness 6.88 mm, 12.75 ppf) in the RGF well. Corrosion rates were predicted using Electronic Corrosion Engineer (ECE) based on the de Waard semi-empirical model, while tubing integrity was assessed using StressCheck under burst, collapse, axial, and triaxial (Von Mises) loading conditions. The critical wall-loss limit was set at 2.13 mm (31% of the nominal wall thickness) based on US Patent No. 7,518,526 B2. Corrosion rates ranged from 0.24 to 1.23 mm/year and decreased after peaking in 2031 due to the formation of a protective FeCO? layer. At the critical wall loss, the collapse design factor no longer met the acceptance criterion, although burst, axial, and triaxial criteria remained acceptable, indicating loss of tubing integrity. Three tubing replacements are projected during the 2029–2040 production period. Corrosion inhibitor injection (90% availability and 90% efficiency) reduced the maximum corrosion rate by approximately 80.5%. In addition, API 5CT Grade L80 Type 13Cr tubing was identified as a more suitable material than carbon steel for improving CO? corrosion resistance. Therefore, corrosion inhibitor injection and the use of 13Cr tubing are recommended as long-term mitigation strategies.