Why weight is a selection, not a detail
Nominal weight — pounds per foot — is one of the fields a casing specification states, alongside wall thickness, inside diameter and drift diameter. Sizes and grades are published as separate lists — the size list runs 4-1/2 in to 20 in, and the grade list names J55, K55, N80, L80 and P110; an enquiry line states the size and the grade for its interval from the two lists. The weight and grade lines of an enquiry are written from the design's load cases for the interval.
Weight, wall, inside diameter and drift
| Specification field | What the field names |
|---|---|
| Nominal weight | The weight per foot stated for the joint |
| Wall thickness | The wall stated for the joint |
| Inside diameter | The bore diameter stated for the joint |
| Drift diameter | The drift diameter stated for the string |
Drift deserves its own paragraph because it outlives the drilling phase. The drift diameter is the figure the design states for the string. This is the mechanism that connects drift to the special clearance coupling: when drift is tight, the coupling OD is where the clearance is recovered.
The fields an enquiry states
State the load cases for each interval — collapse, burst, tension — and the design factors your standard requires in the enquiry, interval by interval: the weight and grade lines of an enquiry are written from the figures the design states. The drift figure is a design input of the same kind: the design states it for the string.
The company's product literature describes the inspection side that stands behind a casing line: automatic flaw detection and hydrostatic testing, automatic marking and painting lines, and ultrasonic thickness measurement are in the equipment list its casing pages publish, and casing packing is by steel strap or steel frame, or as agreed in the order. Send the interval data with an enquiry and ask for two weight options to be priced side by side where the design allows both; the choice between them stays with the design office.
What is drift diameter in plain terms?
The drift diameter figure the design states for the string. The design states what must pass through the casing, and the drift figure it must fit inside, with the working margin the design sets.
Can a heavier weight substitute for a higher grade?
The trade is calculated per interval by the design: the weight line and the grade line are separate fields of one specification. State any hardness or corrosion requirement from your specification in the enquiry. State the size, weight and grade for the interval in the enquiry, and ask for the combination to be confirmed in the quotation.
Do you publish the full weight table?
The published size data is the fourteen-size casing list, from 4-1/2 in to 20 in. For the weight line of a given size, state the size and the grade in the enquiry, and ask for the weight to be confirmed in the quotation.
Request a Quotation
Send your size, grade, thread and quantity. MOQ, packing and lead time are confirmed in the quotation for your exact specification — no generic promise replaces a written quote.