Seamless well casing with the grade, wall and connection kept together
We supply seamless API 5CT casing for oilfield distributors and well contractors. Our published casing range runs from 4½ to 20 in. OD, with J55 and K55 as the core selections. Each quoted line retains its wall or nominal weight, connection and length requirement, so a casing string arrives under the specification used in the well program.
| Manufacturing route | Seamless steel casing |
|---|---|
| Core material selection | API 5CT J55 and K55 |
| Published outside diameter | 4½–20 in. |
| Connection families | Short-round, long-round, buttress or plain ends, identified by the order |
| Length basis | The specified length range plus the delivered joint tally |
| Other material or connection requirements | Quoted as separate lines against the complete designation |
Use the body diameter and wall together when checking the casing schedule. Thread and coupling dimensions belong to the connection drawing.
| Casing OD (in.) | Casing OD (mm) | Nominal wall (in.) | Wall equivalent (mm) |
|---|---|---|---|
| 4½ | 114.3 | 0.205 | 5.21 |
| 4½ | 114.3 | 0.224 | 5.69 |
| 4½ | 114.3 | 0.250 | 6.35 |
| 6⅝ | 168.3 | 0.288 | 7.32 |
| 6⅝ | 168.3 | 0.417 | 10.59 |
| 10¾ | 273.1 | 0.350 | 8.89 |
| 10¾ | 273.1 | 0.400 | 10.16 |
| 10¾ | 273.1 | 0.450 | 11.43 |
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Selected J55/K55 entries from our casing catalog. Inch walls are retained; metric wall equivalents use 25.4 mm per inch and are rounded to two decimals. The order also identifies connection and nominal mass designation.
J55 and K55 stay distinct despite the shared strength number. Material identity, test requirements and the approved grade remain attached to the casing line. A different grade is a substitution requiring its own approval.
API 5CT addresses casing and tubing delivery requirements. For an 11th-edition order, supplementary requirements are specified by their actual clauses or SR designations, which set the complete inspection scope.
N80 types, L80 material types and other project grades need their complete designations. Sour-service suitability, collapse performance and connection sealing are separate requirements, each named on the order.
Short-round and long-round casing connections use their own coupling and thread geometry. Retaining the connection designation prevents a joint from being supplied against a similar-looking end that belongs to another casing string.
Buttress thread form is distinct from round casing threads. The matching coupling, connection drawing and required handling compound belong with that end form. Acceptance is gauged against the connection drawing.
Plain-end casing leaves the final connection work outside the supplied end finish. The required end allowance and subsequent processing route affect the finished joint length and should be included in the material schedule.
A well program distinguishes surface, intermediate and production strings. Our casing quotation follows those separate line items, preserving changes in body wall, material and connection through the string.
Replacement work needs a positive match to the existing casing designation and mating equipment. The body OD is only the starting point; connection type and the required drift clearance decide whether the replacement fits.
A drift test uses a mandrel with a specified diameter and length. The mandrel pass establishes that the required tool envelope clears the delivered casing.
Thread geometry and visible end condition are checked before protectors are fitted. Handling dents, contaminated threads and damaged crests affect assembly even where the pipe body remains undamaged.
Heat or lot references connect pipe markings with the material and inspection records agreed for the order. Hydrostatic test pressure is recorded as an acceptance-test condition. Well operating pressure is set by the completion design.
Threaded ends travel with protectors selected for the end form. Supports and restraints keep the connection areas clear of hard contact, while exposed surfaces retain the preservation treatment specified for shipment.
A casing range is a length category, not a promise that every joint has an identical length. The shipment tally records individual joints and total footage so the receiving team can reconcile the actual string material.
The offer identifies body size, wall or nominal mass, grade, connection work and quantities. Packing, production timing and the delivery basis are priced for the actual order and destination.
J55 and K55 remain different API grade designations. Matching OD and wall does not make the material substitution acceptable. The well program and purchase specification determine which grade can be supplied.
No. The product specification and the right to apply the API Monogram are separate matters. An order requiring Monogrammed casing needs the actual licensed manufacturer and the applicable product scope identified; a standard name in a quotation is not that evidence.
No. Plain-end weight describes the pipe body basis. A threaded-and-coupled designation includes the relevant end configuration. Keep the weight basis on the order so the selected wall and commercial quantity match the intended casing.
State the required mandrel diameter and length, the joints to be checked and any specified procedure or witness point. A special drift is an additional acceptance requirement; naming a nominal pipe bore does not define it.
A photograph can show damage or general end form, but it cannot establish the complete connection geometry. Use the original casing designation, connection drawing or verified inspection information to specify a replacement; visually similar pins may belong to different connections.
List the casing size, connection designation, coupling grade or specification and piece count. Coupling size is tied to the mating casing connection; a generic pipe coupling of similar diameter is a different item.
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Attach the casing schedule with OD, wall or nominal lb/ft, grade, connection, length range and quantity. Add the destination and any special drift or inspection requirement. Our offer returns the proposed combination and supply terms for each casing line.