APPARATUS AND METHOD FOR CONTROLLED PRESSURE DRILLING.

摘要

A rotating flow head (RFH) has a housing having an internal bore with diameter substantially equal to that of a riser and at least one flow port proximate one longitudinal end thereof. First and second arrays of radially extensible and retractable locking elements are disposed circumferentially around the RFH housing. The RFH has a bearing assembly (BA) housing having an exterior diameter selected to fit within the internal bore of the RFH housing so as to provide an annular space therein. The BA housing has profiles for engaging one of the arrays of locking elements when extended. A mandrel is rotatably, sealingly supported within the BA housing. Another end of the BA housing and the other array of locking elements have features cooperative to provide longitudinal force on the BA housing to energize a seal element disposed in the annular space when the other array is extended.