PRESSURIZING ROTATING CONTROL DEVICES

摘要

A rotating control device (RCD), for use in drilling a wellbore, includes an RCD body, a sealing element, and a bearing assembly disposed within the RCD body and supporting an inner mandrel to rotate relative to the RCD body. The sealing element is carried by the inner mandrel, and the bearing assembly includes a bearing sealed in an internal bearing fluid chamber. The internal bearing fluid chamber includes a bearing fluid maintained at a pressure greater than a pressure of wellbore fluid in an interior of the RCD body by a pressure compensating piston between the bearing fluid contacting a first end of the piston and the wellbore fluid contacting a second, opposite end of the piston.