Expandable locking thread joint

摘要

A thread for expandable downhole tubular connections is disclosed. The thread on at least one of the pin and box is coated, preferably with an anti-galling compound. During expansion the coating crumbles and the particles in between the threads keep the joint from becoming undone despite longitudinal shrinkage from the expansion or any tendency of the swage to impart a rotational motion on one part of the joint during the expansion process.