OCTG Casing & Tubing
Oil country tubular goods (OCTG) is the category of steel pipe used in oil and gas well construction — casing, tubing, and drill pipe. Casing is the structural pipe that lines the wellbore and isolates geological formations. Tubing is the smaller-diameter pipe inside the casing through which well fluids are produced to surface. Both are manufactured to API 5CT specifications and supplied in a range of steel grades for different well conditions.
What OCTG Covers
| Product | Function | Key Specification |
|---|---|---|
| — | — | — |
| Surface casing | Isolates shallow fresh water zones, provides BOP support | Larger diameter, lower grade |
| Intermediate casing | Isolates problematic formations, allows drilling to continue | Intermediate size, various grades |
| Production casing | Final casing string, provides the pressure boundary for completion | Various sizes, grades matched to well |
| Production tubing | Conduit for produced fluids from reservoir to surface | Smaller diameter, API 5CT |
| Liner | Partial casing string — hung inside a previous string | All sizes, tied back or hanging |
Casing
Hunting sources casing from leading global mills and supplies it with API 5CT connections or Hunting premium connections (SEAL-LOCK® family, TEC-LOCK™). Standard API grades include J55, K55, N80, L80, C90, C95, T95, P110, and Q125. Premium grades are available for HPHT and sour service applications.
Casing is supplied in 40-foot (12.2 m) range 3 lengths. Other range lengths available on request. All casing supplied with Hunting connections is inspected and drifted before shipment.
Tubing
Production tubing is supplied in 2⅜", 2⅞", 3½", and 4½" OD sizes in standard API 5CT grades. Tubing with Hunting premium connections is available for gas wells and applications requiring metal-to-metal gas-tight sealing. Upset configurations — external upset (EUE), integral (IJ), and non-upset — are available to match packer and completion equipment requirements.
Steel Grades and Material Standards
| Grade | Application |
|---|---|
| — | — |
| J55, K55 | Surface casing, low-pressure applications |
| N80, L80 | Standard production casing and tubing |
| L80 9Cr, 13Cr | Corrosive service (CO₂, mild H₂S) |
| C90, T95 | Sour service — NACE MR0175 compliant |
| P110 | High-strength, deep wells |
| Q125 | Ultra-high-strength, very deep or high-pressure wells |
All grades supplied to API 5CT. NACE MR0175-compliant grades available for sour service. Full material traceability — mill test reports and heat certificates — provided with every order.
Why Source Through Proxima
Hunting supplies OCTG from mills in the USA, Europe, and Asia — providing access to a global supply network with short lead times compared to single-source supply chains. Proxima coordinates OCTG procurement for Azerbaijan and regional markets, managing import documentation, logistics, and delivery to Baku port or drilling location. Mill test reports and full material traceability are provided with every shipment.
Frequently Asked Questions
Q: How do I specify casing for my well programme?
Casing specification requires: OD (inches), weight (lb/ft), grade, thread/connection type, and range length. Your wellbore design and casing design will determine these parameters. Proxima engineers review your casing design and confirm the correct specification before ordering.
Q: What lead time should I expect for OCTG from Hunting?
Lead time depends on size, grade, and connection type. Common sizes in standard grades with API connections are often available from Hunting stock or short lead time. Premium connection sizes require threading lead time. Contact Proxima with your requirement for a current lead time estimate.
Q: Can Proxima supply OCTG with inspection and documentation for import into Kazakhstan?
Yes. Hunting provides full API 5CT documentation — mill test reports, heat certificates, dimensional inspection reports — required for customs clearance and regulatory acceptance in Kazakhstan and other regional markets. Proxima coordinates the documentation package for each shipment.
Q: Is 13Cr tubing available for CO₂ service?
Yes. 13Cr tubing (L80 13Cr) is available for wells producing CO₂ where standard carbon steel tubing would experience accelerated corrosion. Specify CO₂ partial pressure and temperature when ordering. Proxima confirms the correct grade and connection for your well conditions.
