HIGH COLLAPSE CASING FOR DEEP WELL SERVICE
Oil Country Tubular Ltd. (OCTL) High Collapse Casing OCTL HC grades are a seamless product designed for deep wells where high collapse pressures are anticipated. In order to meet deep well service requirements, OCTL HC casing has improved collapse properties well in excess of API ratings. These properties are achieved by strict mill control incorporating a unique production technique inclusive of quenching and tempering. OCTL HC casing shows a very high resistance to tension load, internal pressure, and collapse. OCTL HC-95 SS is also highly resistant to sulfide stress corrosion cracking and can be used for deep and sour gas and oil service.
As wells are drilled deeper, the external pressures applied to well casings become greater. Thus, a well casing must have adequate collapse strength to withstand these horizontal pressures without deformation.
With this in mind OCTL has developed its High Collapse Casing. This casing was developed from experiments in which OCTL studied the critical collapse pressure of a well casing under external pressure in relation to its longitudinal tensile strength and the geometry of its cross section.
OCTL is fully equipped to conduct High Collapse Pressure Tests. The equipment is designed and supplied by SOUTH WEST RESEARCH INSTITUTE, USA.
The Collapse Pressure Testing System is a 15 inch ID Chamber designed for 20,000 psi maximum working pressure. The system is capable of testing the size range 4 1/2” OD to 20” OD casing pipes of different wall thicknesses/ plain end weights for collapse pressure values of API grades and High Collapse grades.
As wells are drilled deeper, the external pressures applied to well casings become greater. Thus, a well casing must have adequate collapse strength to withstand these horizontal pressures without deformation.
With this in mind OCTL has developed its High Collapse Casing. This casing was developed from experiments in which OCTL studied the critical collapse pressure of a well casing under external pressure in relation to its longitudinal tensile strength and the geometry of its cross section.
Characteristics
1. Unique Production Technique
The material for OCTL HC casing is carefully selected to ensure structural homogeneity. Strict control of heat treatment and dimensional tolerances is adhered to through all the processing stages.2. Rigid Dimensional Control
Dimensional tolerances, such as Roundness, Straightness, Outside Diameter and Wall Thickness are strictly controlled.3. Specified Collapse Value
Collapse test is carried out on each production run of OCTL HC casing with the same frequency as the tensile test using the most modern testing equipment.| Grade | Yield Strength | Tensile Strength | Elongation % |
Collapse Resistance | |
| minimum psi (MPa) |
maximum psi (MPa) |
minimum psi (MPa) |
|||
| OCTL HC L-80 | 80,000 (552) | 110,000 (758) | 100,000 (689) | API formula | Minimum Guaranteed is 20% more than API values |
| OCTL HC T-95 | 95,000 (655) | 125,000 (862) | 110,000 (758) | API formula | |
| OCTL HC P-110 | 110,000 (758) | 140,000 (965) | 125,000 (862) | API formula | |
| OCTL HC Q-125 | 125,000 (862) | 155,000 (1069) | 135,000 (931) | API formula | |
OCTL is fully equipped to conduct High Collapse Pressure Tests. The equipment is designed and supplied by SOUTH WEST RESEARCH INSTITUTE, USA.
The Collapse Pressure Testing System is a 15 inch ID Chamber designed for 20,000 psi maximum working pressure. The system is capable of testing the size range 4 1/2” OD to 20” OD casing pipes of different wall thicknesses/ plain end weights for collapse pressure values of API grades and High Collapse grades.
Casing
