API 5CT P110 - High-Strength Casing/Tubing
API 5CT P110 is a high-strength grade of seamless or welded casing and tubing used in demanding oil and gas wells where very high mechanical strength is required.
Key Features
| Feature | Description |
|---|---|
| Material | High-Strength Carbon-Manganese Steel |
| Primary Use | Deep, high-pressure wells |
| Key Property | Very high yield strength |
| Heat Treatment | Quenched & Tempered (mandatory) |
Mechanical Properties
| Property | Requirement |
|---|---|
| Yield Strength | 758-965 MPa (110-140 ksi) |
| Tensile Strength, min | 862 MPa (125 ksi) |
| Hardness | Typically 25-36 HRC |
Important Limitations
⚠️ P110 is NOT suitable for sour service (H₂S environments)
Hardness typically exceeds NACE MR0175 limits (>22 HRC)
No special chemistry controls for SSC resistance
Use C110/T95 for high-strength sour service
Applications
| Application | Reason for Use |
|---|---|
| Deep production casing | Withstands high overburden pressures |
| High-pressure liner | Resists burst and collapse in HP zones |
| Heavy-weight casing strings | Supports long string weights |
| Deep, high-pressure gas wells | Contains high reservoir pressures |
Comparison with Other Grades
| Grade | Yield (ksi) | Sour Service? | Best For |
|---|---|---|---|
| N80 | 80-110 | No | Medium-depth wells |
| L80 | 80-95 | Yes | Sour service wells |
| P110 | 110-140 | No | Deep, high-pressure wells |
| C110/T95 | 110-125 | Yes | High-strength sour service |
Design Considerations
Collapse Resistance: Excellent due to high strength and typically thicker walls.
Burst Resistance: Very high internal pressure rating.
Connection Selection: Premium connections strongly recommended due to high loads.
Notch Sensitivity: Higher than lower grades - careful handling required.
Common Specifications
| Size Example | Weight | Typical Use |
|---|---|---|
| 5½" P110 | 17-26 lb/ft | Production casing |
| 7" P110 | 23-35 lb/ft | Production casing/liner |
| 9⅝" P110 | 40-53.5 lb/ft | Intermediate casing in deep wells |
Ordering Example
API 5CT P110 Casing, 7" 26#, Range 3, Premium Connection. For deep sweet gas well service.
In summary: API 5CT P110 is the standard high-strength workhorse for deep, high-pressure wells in non-sour (sweet) environments. It provides approximately 40% higher yield strength than N80, enabling well designs that would otherwise be impossible with lower grades.
