A Buyer’s Guide to Purchasing OCTG for International Oil and Gas Projects

Buying OCTG (Oil Country Tubular Goods) for international projects comes down to three controls: the right API 5CT grade, full mill traceability, and a supplier who documents both before shipment. Drilling and completion programs in importing markets worldwide run on casing and tubing that must arrive on schedule and to specification — this guide covers what a procurement team should check before issuing a purchase order to any OCTG supplier.

What counts as OCTG

OCTG covers three product families: drill pipe (rotates the bit and circulates drilling fluid), casing (lines the drilled wellbore and carries the wellhead loads) and tubing (the production string through which oil or gas flows). All three are manufactured and tested to API Specification 5CT, with connections machined to API 5B.

Choosing the API 5CT grade

The grade is set by well depth, pressure and the corrosivity of the produced fluid:

• J55 and K55 — shallow wells and water strings; the workhorse grades for many onshore programs worldwide.
• N80 and L80 — deeper wells; L80 (including 13Cr variants) where CO2 or mild sour service is expected.
• C90, T95 — controlled-yield grades for sour service to NACE MR0175 / ISO 15156.
• P110, Q125 — high-pressure, high-load casing strings.

Five checks before you order

1. Mill test reports to EN 10204 3.1 or 3.2 — chemistry, mechanical properties and hydrostatic test results traceable to heat numbers.
2. API monogram status of the manufacturing mill, not just the trading company.
3. Connection and thread protection — API 5B threads gauged, protectors fitted for ocean freight.
4. Range and drift — confirm Range 2 or 3 lengths and drift diameter against your completion design.
5. Export documentation — packing lists per bundle, certificates of origin and, for U.S.-routed supply, export-control screening.

Why global buyers source OCTG through an independent sourcing company

An independent sourcing company like Rastemex Group LLC prices one OCTG requisition from several qualified mills across markets, compares offers on grade, wall thickness, connection, delivery and documentation, and manages inspection and freight to the wellsite country. We are capable of shipping to all parts of the world, except countries under United States sanctions and destinations restricted by law. The result is market-wide pricing and a single accountable counterpart — with every quotation in writing. Full scope: OCTG and oilfield supplies.