Drilling string back off sub apparatus and method for making and using same

摘要

A back-off sub apparatus is disclosed. The apparatus includes a connection connecting a rotational section and a non-rotational section. The rotational section is designed to be rotated via a ball dropped into the well under sufficient pressure to cause the rotational section to rotate relative to the non-rotational section supplying a controlled and sufficient torque to the connection to break the connection. The connection then is unthreaded by normal surface action. The disconnected or upper section of the apparatus and the drill string section associated with it can be withdrawn from the well leaving the lower portion and the drill string section associated with it in the well.