Abstract: Tubular ends are heated to a predetermined temperature above 1200 degrees Celsius and surrounded by a shield gas when the tubular ends are pressed together to form forge welded tubular ends. The forge welded tubular ends are then cooled down rapidly from said temperature above 1200 to at most 600 degrees Celsius within 3 minutes after the forge welding operation.

Abstract: A drill bit for drilling a borehole in an object, the drill bit having a central longitudinal axis and having a bit body provided with a central shank for connecting the drill bit to a drilling system. The drill bit further has at least one cutting arm, each cutting arm being provided with a set of cutters for cutting the object and being coupled to the bit body via pivot means allowing the cutting arm to pivot between a radially retracted position and a radially expanded position. The drill bit is provided with support means for supporting the cutting arm in the radially expanded position thereof, wherein the support means is arranged to transmit at least a portion of the rotational torque generated during drilling, from the cutting arm to the bit body so as to reduce or prevent transmission of the rotational torque via the pivot means.

Abstract: An expander system for radially expanding a tubular element from a first inner diameter to a second inner diameter larger than the first inner diameter, the expander system including an expander movable between a radially retracted mode and a radially expanded mode, wherein the expander includes an expansion surface extending in axial direction of the expander and being operable to expand the tubular element upon movement of the expander from the retracted mode to the expanded mode thereof, the expansion surface being of increasing diameter in axial direction of the expander.

Abstract: An expander system for radially expanding a tubular element having an unexpanded portion of a first inner diameter, the expander system including an expander movable between a radially retracted mode and a radially expanded mode, the expander being operable to expand the tubular element from the first inner diameter to a second inner diameter larger than the first inner diameter by movement of the expander from the radially retracted mode to the radially expanded mode thereof, wherein the expander has a contact section of a diameter larger than the first inner diameter when the expander is in the radially retracted mode, and wherein the contact section is arranged to prevent axial movement of the expander through the unexpanded portion of the tubular element when the expander is in the radially retracted mode.

Abstract: An improved method of permanently marking the location of a tubular joint, the method including creating a cavity into the end surface of one of the tubular ends that are to be joined by a forge weld or screw thread connection, inserting a marker into said cavity and subsequently joining the tubular ends.

Abstract: The invention relates to a method for forge welding tubulars such that formation of upsets in the welding zone is minimized which involves shaping the tubular ends that are to be welded together into an inwardly sloping configuration such that when the tubular ends are heated during the forge welding process the heated tubular ends deform as a result of thermal expansion into a substantially longitudinally oriented cylindrical shape.

Abstract: A method of injecting a stream of treatment fluid into an earth formation in the course of drilling a borehole into the earth formation, using an assembly having a drill string provided with at least one sealing means arranged to selectively isolate a selected part of the borehole from the remainder of the borehole, the drill string further being provided with a fluid passage for the stream of treatment fluid into the selected part of the borehole, the method involving: operating the drill string, and stopping the drilling operation when a zone for which treatment is desired is arranged adjacent to the part of the selected part of the borehole; isolating the selected part of the borehole using the sealing means so as to seal the drill string relative to the borehole wall; and, pumping the stream of treatment fluid via the fluid passage into the selected part of the borehole and from there into the treatment zone.