API 5CT Grade-to-Service Selector

Pick your well conditions; we point you to the API 5CT grade. Sour service is gated by H₂S partial pressure (≥0.05 psia) and controlled hardness, not by yield strength.

Approximate well depth / pressure Shallow / low pressure (< ~8,000 ft) Medium (~8,000–12,000 ft) Deep / high pressure (> ~12,000 ft or > 10,000 psi) Ultra-deep HPHT (> ~18,000 ft) H₂S (sour service, partial pressure ≥ 0.05 psia)? No (sweet)Yes (sour) Significant CO₂ corrosion? NoYes Recommend Grade

Guidance only — final grade selection requires a well-design review of H₂S/CO₂ partial pressures, chlorides, temperature and pH. Sour grades supplied with NACE MR0175 / EN 10204 3.1 documentation.