P110 Casing: API 5CT High-Strength Casing for Deep GCC Wells

P110 goes into the deepest, highest-pressure casing strings, and the strength that earns it that place also makes it vulnerable to sulphide stress cracking wherever a sour well runs cool. Placement is everything. P110 casing to API 5CT is the Group 3 high-strength grade, quenched and tempered to a yield range of 758 to 965 MPa, and it delivers about 37% more burst capacity than L80 or N80 in the same size and weight. It is specified for deep gas wells, high-pressure production casing and liners across Oman, usually in the hotter lower sections of a well. Other grades are compared on the API 5CT casing and tubing hub.

Where P110 Casing Is Specified

Production casing and liners in deep, high-pressure oil and gas wells
Deep intermediate strings where burst and tension loads exceed what 80 ksi grades can carry at a practical weight
High-pressure gas wells, often with premium gas-tight connections
Fracturing and stimulation strings, where short-term pressures are very high
Hot, deep sections of sour wells, above the minimum temperature at which ISO 15156-2 accepts P110
P110 tubing in high-pressure sweet wells

For moderate depths, N80 casing and tubing is more economical. For sour sections at all temperatures, L80 sour service tubing and casing or the higher-strength Group 2 grades C90 and T95 are used instead.

P110 Mechanical Properties

Property	P110
Group	3
Yield strength (0.6% total elongation under load)	758 to 965 MPa (110,000 to 140,000 psi)
Minimum tensile strength	862 MPa (125,000 psi)
Hardness	Not specified
Heat treatment	Quenched and tempered
Charpy impact	Required by API 5CT, with minimum energy depending on size and specimen orientation
Colour band	One white

Note that P110's yield is measured at 0.6% total elongation under load, rather than the 0.5% used for J55, N80 and L80. That is a detail worth checking when comparing certificates across grades.

P110 Chemical Composition

Element	Maximum
Phosphorus (P)	0.030%
Sulphur (S)	0.030%

API 5CT leaves carbon, manganese and alloying to the mill. To reach P110 strength with enough toughness, mills typically use chromium-molybdenum or similar low-alloy steels, fully quenched and tempered. Operator specifications often add limits on phosphorus, sulphur and carbon equivalent, so send yours if it sets chemistry.

Why Choose P110: A Burst Comparison in 7 in Casing

A design needs 7 in production casing rated for at least 83 MPa (12,000 psi) burst. Using the API formula P = 0.875 × 2 × Yp × t / D:

Weight	Wall	Drift	L80 burst	P110 burst
29 lb/ft	10.36 mm (0.408 in)	153.90 mm (6.059 in)	56.3 MPa (8,160 psi)	77.4 MPa (11,220 psi)
32 lb/ft	11.51 mm (0.453 in)	151.61 mm (5.969 in)	62.5 MPa (9,060 psi)	85.9 MPa (12,460 psi)
35 lb/ft	12.65 mm (0.498 in)	149.33 mm (5.879 in)	68.7 MPa (9,960 psi)	94.5 MPa (13,700 psi)

None of the L80 weights shown reaches 12,000 psi. P110 at 32 lb/ft does, with a drift of 151.61 mm, leaving room for tools and completion equipment. Reaching the same burst in L80 would need a much heavier wall and a smaller drift. That is the case for P110 in a single table. Collapse, tension and connection strength must also be checked to API TR 5C3 and the operator's casing design standard, and sour service limits may rule P110 out regardless of burst.

P110 Casing and Tubing Sizes, Weights and Burst Ratings

Burst values below use Yp = 110,000 psi in the API formula.

P110 casing

OD	Weight	Wall	ID	Drift	Burst
139.70 mm (5-1/2 in)	17 lb/ft	7.72 mm (0.304 in)	124.26 mm (4.892 in)	121.08 mm (4.767 in)	73.4 MPa (10,640 psi)
139.70 mm (5-1/2 in)	20 lb/ft	9.17 mm (0.361 in)	121.36 mm (4.778 in)	118.19 mm (4.653 in)	87.1 MPa (12,640 psi)
139.70 mm (5-1/2 in)	23 lb/ft	10.54 mm (0.415 in)	118.62 mm (4.670 in)	115.44 mm (4.545 in)	100.1 MPa (14,520 psi)
177.80 mm (7 in)	29 lb/ft	10.36 mm (0.408 in)	157.07 mm (6.184 in)	153.90 mm (6.059 in)	77.4 MPa (11,220 psi)
244.48 mm (9-5/8 in)	47 lb/ft	11.99 mm (0.472 in)	220.50 mm (8.681 in)	216.54 mm (8.525 in)	65.1 MPa (9,440 psi)
244.48 mm (9-5/8 in)	53.5 lb/ft	13.84 mm (0.545 in)	216.79 mm (8.535 in)	212.83 mm (8.379 in)	75.2 MPa (10,900 psi)

P110 tubing

OD	Weight	Wall	ID	Drift	Burst
73.02 mm (2-7/8 in)	6.5 lb/ft	5.51 mm (0.217 in)	62.00 mm (2.441 in)	59.61 mm (2.347 in)	100.2 MPa (14,530 psi)

More sizes and weights are in the API 5CT OCTG grade guide.

Manufacturing: seamless pipe, or electric welded pipe where the order permits, quenched and tempered.

Connections: BTC or LTC on casing; high-pressure gas wells commonly specify premium gas-tight connections, supplied to the buyer's specified design. EUE or NUE on tubing.

Lengths: casing Range 1 (4.88 to 7.62 m), Range 2 (7.62 to 10.36 m) or Range 3 (10.36 to 14.63 m). Range 2 fits a 40 ft container; Range 3, the usual choice for deep wells, ships on flat racks or as break bulk into Sohar, Duqm, Salalah, Jebel Ali or Dammam.

Sizes are supplied to specification. Send your OD, weight, connection and range.

P110 in Sour Wells: Where It Can and Cannot Go

NACE MR0175 / ISO 15156-2 accepts P110 for sour service only above a minimum service temperature. At lower temperatures, its high strength makes sulphide stress cracking a serious risk. Because a well cools towards the surface, P110 in a sour well is normally confined to the deeper, hotter sections, with sour-resistant Group 2 grades such as L80 Type 1, C90 or T95 above it.

Temperature has to be judged over the whole life of the well, not just during production. Shut-in periods, injection and cool-down after stimulation can all bring P110 below its limit. Designers should read the exact threshold from the current ISO 15156-2 and check it against the lowest temperature each section will see.

Where high strength is needed in cooler sour sections, T95 or C90 are the usual answer, trading a little strength for sour acceptance at all temperatures. State your sour service and testing requirements in the RFQ; they are confirmed at quotation. See the NACE MR0175 sour service guide.

Standards for P110: API 5CT and ISO 11960

P110 is defined in API 5CT, with technically equivalent requirements in ISO 11960. There are no EN, DIN or JIS equivalents, since casing and tubing grades are specified to API and ISO worldwide. Casing design follows API TR 5C3.

Operators in the region often order P110 to PSL-2 or PSL-3, with extra Charpy testing, full-length NDT, special drift and specified premium connections. Send your specification with the enquiry and the offer will be prepared against it.

P110 Certificates and Inspection

P110 casing is supplied with EN 10204 3.1 mill test certificates as standard, and EN 10204 3.2 certificates on request. Inspection by the buyer's nominated third-party agency can be arranged; state your requirement in the RFQ. A P110 package should include chemistry, tensile results, Charpy impact results, heat treatment records, hydrostatic test, drift, full-length NDT and thread gauging, plus connection inspection records for premium threads. Check the single white colour band on delivery. See the MTC and EN 10204 certification guide.

P110 Casing Price Factors

P110 is quoted per enquiry, as steel prices and mill schedules move. The main drivers:

Premium connections, often a large share of the total for gas wells
Size, weight and range length
PSL-2 or PSL-3 and supplementary testing
Special drift or tighter tolerances
Casing or tubing
Quantity and mill minimums
Stock availability versus a mill order
Certification (3.1 or 3.2) and third-party inspection
Incoterm, destination port and flat rack freight for Range 3

Quotations are available in USD, OMR, AED, SAR, QAR, KWD and BHD, on EXW, FOB, CFR or CIF terms.

What to send for a quotation:

grade, casing or tubing, OD, weight per foot, connection, range length, quantity, PSL, special drift, Charpy or other supplementary tests, sour temperature conditions if the well is sour, certification, inspection, destination port and required date.

Handling and Storing P110 on Gulf Yards

Lead time is confirmed at quotation.

P110 casing ships with thread protectors on every pin and box and storage compound on the threads. Premium connections need their own protectors kept on until make-up, since a damaged seal area can cause a gas leak at pressure. Rack casing off the ground with a slight slope, renew storage compound during long storage in humid coastal yards, and use UV-stable protectors if casing will sit in the sun. On a mixed yard, keep P110 clearly separated from L80, T95 and C90 of the same size, because running P110 in the wrong section of a sour well is a serious error.

Related OCTG and Surface Products

API 5CT casing and tubing hub
J55 and K55 casing for surface strings
API 5L line pipe and RTJ ring type joint flanges for high-pressure surface connections

P110 is used across oil and gas and upstream oil and gas and sour service wells.

P110 Casing FAQ

What is the yield strength of P110 casing?

Yield must fall between 758 and 965 MPa (110,000 to 140,000 psi), measured at 0.6% total elongation under load. Minimum tensile strength is 862 MPa (125,000 psi).

How much stronger is P110 than L80?

Its minimum yield is 110,000 psi against 80,000 psi, so burst ratings are about 37% higher in the same size and weight. For 9-5/8 in 47 lb/ft casing, burst rises from 6,870 psi in L80 to 9,440 psi in P110.

Can P110 be used in sour wells?

Only above a minimum service temperature set in ISO 15156-2. It is normally confined to the deeper, hotter sections of a sour well, with L80, C90 or T95 in the cooler sections above.

Does P110 require Charpy testing?

Yes. API 5CT requires Charpy impact testing for P110, with the minimum energy depending on size and specimen orientation. Operators often add further toughness requirements.

What colour band identifies P110?

One white band on each length.

What should I send for a P110 quotation?

Send the OD, weight, connection, range length, quantity, PSL, special drift, supplementary tests, sour temperature conditions if relevant, certification, inspection, destination port and required date.

Request a Quote for P110 Casing

Send the size, weight, connection, range and quantity, with your well programme or operator specification attached if you have one. Every enquiry is checked against API 5CT before the offer is prepared, so gaps such as a premium connection without a named design, or P110 listed for a cool sour section, are raised at the start.

Request a Quotation

API 5CT P110 Casing for Deep, High-Pressure Wells