Method for reducing diameter reduction near ends of expanded tubulars

摘要

A variety of approaches to reducing or eliminating "end effect" or the tendency of tubular ends to reduce in diameter after expansion are disclosed. Some involve pre-bending the ends outwardly while others involve removing material internally or/and externally near the ends. Yet other approaches feature weakening the ends in other ways including penetration of the tubular material using openings of various shapes including slots or/and holes where the openings are between the tube ends or where they can extend on one or both ends all the way to the end of the tubular. Inserts that are softer than the tube material can be placed near the ends. If there is an end effect, then the protruding material can be pushed out of the way or broken off.