Abstract: A drill string sub for a rotary steerable drilling system wherein a flow diverter is configured, which flow diverter is configured rotatable about a drill string longitudinal axis at a relative rotation frequency relative to the drill string sub, to preferentially direct drilling fluid into a selected azimuth segment which is stationary relative to the flow diverter. A downhole data unit is configured to provide an information signal representing downhole data. An encoder operatively connected to the flow diverter to modulate the relative rotation in accordance with the information signal for transmitting information representing the downhole data to be detected uphole.

Abstract: A rotary steerable drill string (16) employs a drill bit (10) selected to positively contribute to underpressure in a preselected azimuthal segment of the borehole relative to an opposing azimuthal section. Generally, a high flow velocity of drilling fluid in the selected azimuthal segment relative to in other segments will result in a more pronounced underpressure in the selected azimuthal segment. Drill bit designs which locally enhance the drilling fluid flow velocity are proposed to be employed in the present rotary steerable drill string.

Abstract: An apparatus and method for downhole measurement during operation of a drilling system is disclosed.

Abstract: A drill string sub for a rotary steerable drilling system wherein a flow diverter is configured, which flow diverter is configured rotatable about a drill string longitudinal axis at a relative rotation frequency relative to the drill string sub, to preferentially direct drilling fluid into a selected azimuth segment which is stationary relative to the flow diverter. A downhole data unit is configured to provide an information signal representing downhole data. An encoder operatively connected to the flow diverter to modulate the relative rotation in accordance with the information signal for transmitting information representing the downhole data to be detected uphole.

Abstract: An apparatus and method for downhole measurement during operation of a drilling system is disclosed.

Abstract: A rotary steerable drill string (16) employs a drill bit (10) selected to positively contribute to underpressure in a preselected azimuthal segment of the borehole relative to an opposing azimuthal section. Generally, a high flow velocity of drilling fluid in the selected azimuthal segment relative to in other segments will result in a more pronounced underpressure in the selected azimuthal segment. Drill bit designs which locally enhance the drilling fluid flow velocity are proposed to be employed in the present rotary steerable drill string.

Abstract: An insert to convert a conventional rotary drill bit to a rotary steerable bit for a rotational directional drilling system. The insert comprises a cylindrical body adapted to be arranged within an intermediate space of the drill bit for receiving drilling fluid from a drill string and selectively directing the drilling fluid to nozzles of the drill bit. The insert may be rotatable and connected to a geostationary platform. Alternatively, the insert may be fixated in the drill bit, combined with a flow diverter connected to a geostationary platform. The insert is suitable to be introduced in the drill bit at a drilling location, including remote locations and off-shore rigs.

Abstract: A system, method and drill string component for directional drilling of a borehole in a formation is presented. The system includes a rotatable drill string, a rotatable drill bit comprising an intermediate space for receiving drilling fluid from the drill string and at least two nozzles for ejecting the drilling fluid. The system also includes a first rotor section, a flow diverter connected to a downhole end of the first rotor section, and a second rotor section being directly drivable by the drilling fluid and being rotatable with respect to the first rotor section in a second direction opposite to the first direction and at a second rotational speed (?3/2). In addition, the system includes a control unit for controlling the second rotational speed (?3/2) of the second rotor section with respect to the first rotor section.

Abstract: A method, system and bit steering assembly for directional drilling of a borehole in a formation is presented. The method includes the steps of: providing a drill string having a central fluid passage extending along a longitudinal axis of the drill string for passing drilling fluid to the drill bit. The drill bit has a plurality of nozzles for expelling the drilling fluid, wherein each nozzle is arranged eccentrically with respect to the longitudinal axis. The method includes introducing a bit steering assembly, rotating the drill string, and pumping drilling fluid through the central fluid passage. The drilling fluid activates a first impeller of a first rotor section to rotate in a first direction, and activates a second impeller of a second rotor section to rotate in a second direction opposite the first direction. The method includes adjusting a coupling between the first rotor section and the second rotor section.

Abstract: An insert to convert a conventional rotary drill bit to a rotary steerable bit for a rotational directional drilling system. The insert comprises a cylindrical body adapted to be arranged within an intermediate space of the drill bit for receiving drilling fluid from a drill string and selectively directing the drilling fluid to nozzles of the drill bit. The insert may be rotatable and connected to a geostationary platform. Alternatively, the insert may be fixated in the drill bit, combined with a flow diverter connected to a geostationary platform. The insert is suitable to be introduced in the drill bit at a drilling location, including remote locations and off-shore rigs.

Abstract: A method, system and bit steering assembly for directional drilling of a borehole in a formation is presented. The method includes the steps of: providing a drill string having a central fluid passage extending along a longitudinal axis of the drill string for passing drilling fluid to the drill bit. The drill bit has a plurality of nozzles for expelling the drilling fluid, wherein each nozzle is arranged eccentrically with respect to the longitudinal axis. The method includes introducing a bit steering assembly, rotating the drill string, and pumping drilling fluid through the central fluid passage. The drilling fluid activates a first impeller of a first rotor section to rotate in a first direction, and activates a second impeller of a second rotor section to rotate in a second direction opposite the first direction. The method includes adjusting a coupling between the first rotor section and the second rotor section.

Abstract: A system, method and drill string component for directional drilling of a borehole in a formation is presented. The system includes a rotatable drill string, a rotatable drill bit comprising an intermediate space for receiving drilling fluid from the drill string and at least two nozzles for ejecting the drilling fluid. The system also includes a first rotor section, a flow diverter connected to a downhole end of the first rotor section, and a second rotor section being directly drivable by the drilling fluid and being rotatable with respect to the first rotor section in a second direction opposite to the first direction and at a second rotational speed (?3/2). In addition, the system includes a control unit for controlling the second rotational speed (?3/2) of the second rotor section with respect to the first rotor section.

Abstract: Apparatus for sensing the resistivity of geological formations surrounding a borehole includes a tubular body member (1) which is adapted to form a portion of a length of drill string. An antenna (10) is mounted within the body member (1) and the body member (1) has apertures (2) adjacent to the antenna (10) to permit an electro-magnetic signal to pass through the body member (1) after transmission from, or for reception by, the antenna (10).