Abstract: A subpart of a drill string is described having an outer circumferential surface which is contoured and adapted to engage the wall of the borehole with a small angle of attack while exerting during rotary drilling operations an compacting pressure on mud cake and/or cuttings present in the annulus between the drill string and the borehole.

Abstract: The present invention generally relates to an apparatus and methods for improving the stability of a wellbore during drilling operations using a rotary drill string. More specifically, embodiments of the present invention provide systems and methods for enhancing the performance of the filter or mud cake layer on the wall of the wellbore as a protective and isolating layer.

Abstract: A method and system is disclosed for automatically detecting the state of a drilling rig during the drilling process of a wellbore. Two or more, but preferably four independent input data channels are received, each input data channel representing a series of measurements made over time during the drilling process. Based on the input channels the most likely state of the drilling rig is detected from at least three possible rig states. The detection method is preferably probabilistic and even more preferably based on particle filtering techniques. The preferred systems and methods disclosed are also capable of detecting events and displaying or notifying drilling personnel of the detected events and suggesting corrective action.

Abstract: A subpart (430) of a drill string (211) is described having an outer circumferential surface which is contoured and adapted to engage the wall of the borehole with a small angle of attack while exerting during rotary drilling operations an compacting pressure on mud cake and/or cuttings present in the annulus between the drill string and the borehole.

Abstract: A method and system is disclosed for automatically detecting the state of a drilling rig during the drilling process of a wellbore. Two or more, but preferably four independent input data channels are received, each input data channel representing a series of measurements made over time during the drilling process. Based on the input channels the most likely state of the drilling rig is detected from at least three possible rig states. The detection method is preferably probabilistic and even more preferably based on particle filtering techniques. The preferred systems and methods disclosed are also capable of detecting events and displaying or notifying drilling personnel of the detected events and suggesting corrective action.