Oil casing

The most vital standard is API 5CT (American Petroleum Institute), which governs the manufacturing and testing of casing and tubing. You must specify the Steel Grade (e.g., J55, K55, N80, L80, P110) based on the well's depth and pressure. Additionally, ensure the Connection Type (e.g., STC, LTC, BTC, or Premium Connections) matches the structural requirements of the borehole to prevent leakage or collapse.

For wells containing H2S or CO2, you must select Sour Service or Corrosion-Resistant Alloy (CRA) materials. Look for grades like L80-13Cr or those meeting NACE MR0175/ISO 15156 standards. These materials undergo rigorous Sulfide Stress Cracking (SSC) and Stress Corrosion Cracking (SCC) testing to ensure long-term integrity in harsh downhole conditions.

Buyers should demand Non-Destructive Testing (NDT) reports, including Ultrasonic Testing (UT), Magnetic Particle Inspection (MPI), and Hydrostatic Testing. It is also essential to verify the Heat Number traceability on the Mill Test Certificate (MTC) to ensure the chemical composition and mechanical properties (yield strength, tensile strength, and elongation) align with the order specifications.

Surface Casing is used to protect freshwater aquifers and support subsequent casing strings. Intermediate Casing is required for isolating high-pressure zones or unstable formations. Production Casing is the final string that provides a conduit for oil and gas recovery. Each scenario requires different Wall Thickness (Schedule) and Collapse Resistance ratings.

The biggest risks include Material Substitution (using lower-grade steel) and Dimensional Inaccuracies (out-of-roundness or wall thickness variations). To mitigate this, use Third-Party Inspection (TPI) services like SGS or BV at the factory. Always source from Audited Suppliers on Made-in-China.com who possess valid API Monogram Licenses.

Oil casings are heavy and prone to thread damage. Negotiate for FOB or CIF terms that include Thread Protectors (plastic or metal-plastic composite) and Seaworthy Bundling. Ensure the shipping contract specifies Break Bulk or Specialized Container Loading to prevent bending during transit, and confirm the supplier's ability to handle Export Customs Clearance for steel products.

Given the high capital outlay, utilize Letter of Credit (L/C) or Escrow-based payment systems. Avoid full upfront payments; a standard structure is 30% deposit and 70% against the Bill of Lading (B/L) after a successful NDT inspection. Verify the supplier's Business License and Export Qualification through the Made-in-China.com company profile to ensure they are a legitimate manufacturer rather than an unlicensed middleman.

Be aware of Anti-Dumping Duties (ADD) and Countervailing Duties (CVD) that some countries (like the US or EU) impose on Chinese steel pipes. Check your local Customs Tariff Schedule and ask the supplier for a Certificate of Origin to determine the applicable duty rates. Staying informed on Section 232 or similar trade barriers is crucial for accurate Total Cost of Ownership (TCO) calculations.