Patent ID: 11885223
Assignee: THE CHARLES MACHINE WORKS, INC.
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 16:
17. A method for rotating a drill string, the drill string comprising an outer pipe string and an inner pipe string disposed within the outer pipe string, the method comprising: storing, in a memory, predetermined drill string rotation conditions indicative of a drag condition between the inner pipe string and the outer pipe string; rotating the inner pipe string using a first motor; rotating the outer pipe string using a second motor; measuring a first rotation rate of the inner pipe string; measuring a second rotation rate of the outer pipe string; and comparing the first rotation rate and the second rotation rate to the predetermined drill string rotation conditions; if the first rotation rate and the second rotation rate meet the predetermined drill string rotation conditions, rotating the inner pipe string at a rotational velocity equal to the rotational velocity of the outer pipe string; after the step of rotating the inner pipe string at a rotational velocity equal to the rotational velocity of the outer pipe string, discontinuing rotation of the inner pipe string.