OCTG PROCUREMENT GUIDE
Casing Selection Guide
A casing enquiry becomes commercially meaningful only when the tubular schedule is connected to the well duty, governing standard, load basis, service environment, connection and required evidence.
Begin with the casing duty
Surface, intermediate, production and liner strings perform different structural, isolation and pressure-containment roles. The application and setting depth establish the context for size, nominal mass and grade.
- String function and setting depth
- Internal and external pressure cases
- Axial, bending and installation loads
- Temperature and expected service life
Define the complete product designation
Outside diameter alone is not a purchase specification. The enquiry should define size, nominal mass or wall thickness, grade, applicable product requirements, length range and end condition.
- API 5CT / ISO 11960 edition
- Outside diameter and nominal mass
- Grade and heat-treatment condition
- Range, drift and special dimensions
Treat the connection as part of the system
Connection selection affects clearance, sealing, make-up, handling and compatibility with couplings, pup joints and completion equipment.
- Thread form and connection name
- Coupled, integral or special-clearance requirement
- Make-up and running information
- Matching couplings and accessories
Fix verification before quotation
Inspection and documentation should be specified at enquiry stage so competing offers are evaluated on the same basis.
- Material certificates and traceability
- NDT, hydrostatic and dimensional testing
- Thread gauging and end protection
- Third-party inspection and final dossier
ENQUIRY CHECKLIST
Information to prepare.
Use this list as an initial procurement guide. The governing design and purchase documents remain authoritative.
Send Your Requirement- 01Casing schedule with size, mass, grade and quantity
- 02Applicable standard, edition and purchaser specification
- 03Connection, range and accessory requirements
- 04Well environment including H₂S / CO₂ where relevant
- 05Inspection, testing and documentation scope
- 06Destination, schedule, packing and marking