Pipe for oil and gas projects is bought against standards, not catalogues. Two offers for “API pipe” can differ in grade, product specification level, end finish, connection type and testing — and those differences only show up when the pipe reaches the site or the well. This article explains what to put in your enquiry so that suppliers quote the same thing, and what to check before the pipe ships.
Line pipe and OCTG are different products
Line pipe carries oil, gas, water and refined products from wells to processing plants, storage and terminals. It is usually specified to API 5L, in seamless or welded form, with the grade chosen by the pipeline designer for the operating pressure, diameter and fluid.
Oil country tubular goods (OCTG) are the casing and tubing that go inside the well. Casing lines and protects the wellbore; tubing is the conduit the oil or gas flows through to the surface. OCTG is usually specified to API 5CT, with grades selected for depth, pressure and the well environment. Where hydrogen sulphide is present, sour-service requirements apply and the material must be qualified for them.
What to put in a line pipe enquiry
- Standard and product specification level (for API 5L, PSL1 or PSL2) and the grade.
- Seamless or welded, and for welded pipe the process your project accepts.
- Outside diameter, wall thickness, length range and end finish (plain or bevelled).
- Coating requirements, internal and external, as defined in your project specification.
- Any additional project requirements beyond the base standard, such as extra testing or sour-service qualification.
What to put in a casing or tubing enquiry
- Standard, grade, size and weight per foot (or wall thickness).
- Connection type: standard API threads or a premium connection, and the make-up requirements.
- Range length, and whether you need pup joints or couplings.
- Sour-service requirements, if the well calls for them.
Connections deserve particular attention. Premium connections are specified for demanding wells where sealing and load performance matter most; see our premium connections for casing and tubing.
Documents and inspection to ask for
Ask for mill test certificates that report chemical composition and mechanical properties for each heat, with heat numbers traceable to the pipe markings, plus the records of the non-destructive and hydrostatic tests your standard requires. For critical orders, third-party inspection by a body such as SGS or BV is common practice; where you request it through us, the fee is paid by the buyer.
Don’t forget the rest of the line
A pipeline package also needs fittings and flanges in matching materials and ratings. Ordering them on the same schedule as the pipe avoids the common situation where pipe is on site but the fittings are not. See our steel materials and pipes range.
How we work
YuxingCorp coordinates pipe supply from mills and manufacturers we have visited and qualified, together with supplier coordination and shipping and freight logistics coordination. Each shipment comes with a complete export document pack — commercial invoice, packing list, certificate of origin and bill of lading. Import customs clearance, duties, taxes and local registration are the buyer’s responsibility. Our standard payment terms are T/T: 30% deposit and 70% before shipment.
Related reading
- Pipe fittings and flanges: what to specify
- How to source steel materials for infrastructure and industrial projects
- Finned tubes and U-bend tubes for heat exchangers
Send us your pipe schedule
Send the standards, grades, sizes, connection types and quantities, plus the destination and your timeline. We respond within one business day.