P110 Grade Overview
API 5CT P110 is a high-strength steel grade for oil and gas wells, manufactured using the quenching and tempering process with a minimum yield strength of 110,000 psi, about 758 MPa, and a minimum tensile strength of 125,000 psi, about 862 MPa. Designed for deep, ultra-deep, and high-pressure environments, it provides superior mechanical load-bearing capacity and collapse resistance to support the massive weight of long casing strings. Its high hardness and lack of a maximum hardness limit make it unsuitable for sour service containing hydrogen sulfide.
API Buttress Thread Connection
BTC is the most common standard connection for P110 casing. Unlike short or long round threads, the trapezoidal shape of the buttress thread provides much higher tensile, pull-out, resistance. Since P110 is often used in deep wells where the casing string is very heavy, BTC is required to support that weight. It is best for deep vertical wells with high axial loads but moderate pressure, and its limitation is that it is not gas-tight, relying on thread compound to seal.
Premium Connections
For many P110 applications, standard API BTC is insufficient and premium connections with metal-to-metal seals are used. Premium connections provide a gas-tight seal necessary for high-pressure gas wells; handle the high torque required for rotation in horizontal and shale wells; and offer flush or semi-flush profiles for slim-hole wellbores. They are best for high-pressure gas wells, horizontal sections, offshore drilling, and thermal recovery wells.
Why STC and LTC Are Not Recommended
STC and LTC threads are rarely used for P110; they are more common for lower grades such as J55 or K55. Using STC or LTC on P110 pipe creates a weak link, since the connection would likely fail long before the pipe body reaches its yield limit.
Selection Table
| Factor | API BTC | Premium Connections |
|---|---|---|
| Well type | Deep vertical oil wells | High-pressure gas and horizontal wells |
| Sealing | Liquid tight | Gas tight |
| Mechanical stress | Mostly tension | Tension plus torque and bending |
| Cost | Cost-effective | High performance |
Frequently Asked Questions
Q: What is the P110 yield strength?
A: 110,000 to 140,000 psi, 758 to 965 MPa.
Q: Is P110 suitable for sour service?
A: No, it is not hardness-controlled for hydrogen sulfide environments.
Q: When is BTC used?
A:For deep vertical wells with high axial loads and moderate pressure.
Q: When are premium connections used?
A:For high-pressure gas, horizontal, offshore, and thermal wells.
Q: Why avoid STC and LTC on P110?
A: They fail before the pipe body reaches its yield limit.
Q: What is the color code of P110?
A: A white band on the pipe body and coupling.
For P110 casing and premium connection quotations, contact our sales team.
