Synopsis

This paper argues that the mandatory requirements of A.P.I. casing and tubing specifications do not insure that these products will withstand the forces to which they will be subjected. Resistance to these forces, i.e., tension, collapse, and bursting are expressed as performance values as published by the A.P.I. in Bulletin ~CZ :. "Performance Properties of Casing and Tubing." After a discussion of the specifications it is pointed out that compliance with them only indirectly proves the worth of the product. Only, one, the Mill-Incpection Hydrostatic Test, is a direct proof of quality, and it does not go far enough.

Exception is taken to the description of "injurious defects", pointing out that strict adherence thereto does not insure against failure but leads to discarding good product. Data and photographic records are offered on this point.

Reasons are given for believing that defects are not focal points for corrosion. Some persons believe they are, even though satisfied that bad looking pits, seams, etc., seldom cause physical failures.

To avoid arguments on "injurious defects", and to insure proper performance, it is concluded that proof testing of each length is logical. Since tension testing, and especially collapse testing, would be too slow and expensive, internal pressure testing to 80 "/o of the Minimum Yield Strength is recommended.

The A.P.I. has already set up "alternative" (not mandatory) high pressure test figures, and it is argued that pipe which withstands these pressures would not fail under comparable tension and collapse tests. If so tested the user will not need to worry about "injurious defects" because the high pressure test will find them, both the visible and the invisible ones. * Spang Chalfant (National Supply Co.), Tulsa, Okl.

Proceedings 3rd W.P.C., Section II

Résumé

Cette communication s'attache à prouver que les exigences obligatoires des spécifications A.P.I. pour les tubes de revêtement et de production ne garantissent pas que ces produits résisteront aux efforts auxquels ils seront soumis. La résistance à ces efforts, savoir la traction, l'écrasement, l'éclatement, est exprimée en limites d'utilisation comme publié par l'A.P.I. dans le Bulletin 5C2 :, Performance Properties of Casing and Tubing".

Après avoir discuté les specifications, on note que le fait qu'un produit y répond n'en prouve la valeur que d'une manière indirecte. I1 n'y a que le, Mill-Inspection Hydrostatic Test", qui prouve directement la qualité, et encore ne va-t-il pas assez loin.

L'auteur objecte à la description de, défauts nuisibles" exposant qu'en s'en tenant strictement à celle-ci on n'aura aucune garantie contre les défauts, mais qu'on court le risque de rejeter des produits de bonne qualité. Des données et des ph

This content is only available via PDF.
You can access this article if you purchase or spend a download.