Abstract: An apparatus for drilling a subterranean wellbore using a drill string. The apparatus includes a riser, a sealing device arranged in the riser so as to form a first riser chamber and a second riser chamber, and a riser booster pump. The riser at least partly contains the drill string and defines a substantially annular space around the drill string. The second chamber is in a fluid communication with the riser booster pump so that a kill fluid stored in the second riser chamber may be maintained at a first pressure which is greater than a second pressure of a drilling fluid in the first riser chamber.

Abstract: A diverter for diverting a fluid from a riser in a drilling system. The diverter includes a diverter support housing comprising a suspension structure configured so that the diverter support housing is suspendable from a drilling rig, and a main passage arranged to extend from an uppermost end of the diverter support housing to a lowermost end of the diverter support housing. The main passage is configured to have a drill string extend therethrough. A diverter housing is arranged in the main passage. An annular packer element is mounted within the diverter housing. An actuator is mounted within the diverter housing. The actuator is configured to force the annular packer element into a sealing engagement with the drill string. A seal locking mechanism is configured to retain a tubular sealing element in the diverter housing adjacent to the annular packer element.

Abstract: A pressure containment device for sealing around a tubular body comprising an actuator assembly and a seal assembly, the actuator assembly being operable to engage with the seal assembly to prevent significant rotation of the seal assembly with respect to the actuator assembly and to force the seal assembly into sealing engagement with a tubular body mounted in the pressure containment device, the seal assembly comprising a tubular seal sleeve having a radially inward portion made from a non-elastomeric polymer, and a radially outward portion made from an elastomer.

Abstract: A method of operating a system for handling an influx of gas into a marine riser during the drilling of a well bore includes the steps of operating a first riser closure apparatus to close the riser at a first point above a flow spool provided in the riser, there being a riser gas handling line extending from the riser at the flow spool to a riser gas handling manifold, operating a second riser closure apparatus to close the riser at a second point below the flow spool, pumping fluid into an inlet line which extends into the riser at a point above the second point but below the flow spool, and operating a choke provided in the riser gas handling manifold to maintain the pressure in the inlet line or the riser at a substantially constant pressure.

Abstract: A method of operating a drilling system for drilling a subterranean bore hole. The drilling system includes a drill string which rotates during a drilling, and a sealing device which provides a substantially fluid tight seal around the drill string while the drill string is rotating during the drilling. The method includes injecting a fluid into an annular volume around the drill string directly above the sealing device, and controlling a first fluid pressure in the annular volume around the drill string above the sealing device so that the first fluid pressure is greater than a second fluid pressure in the annular volume around the drill string directly below the sealing device.

Abstract: An apparatus for drilling a subterranean wellbore using a drill string. The apparatus includes a riser, a sealing device arranged in the riser so as to form a first riser chamber and a second riser chamber, and a riser booster pump. The riser at least partly contains the drill string and defines a substantially annular space around the drill string. The second chamber is in a fluid communication with the riser booster pump so that a kill fluid stored in the second riser chamber may be maintained at a first pressure which is greater than a second pressure of a drilling fluid in the first riser chamber.

Abstract: A drilling system for drilling a subterranean well bore includes a controller and a first and a second set of field devices. Each of the first and second set of field devices measure a physical characteristic of the drilling system and to transmit to the controller signals representing a measured value of the physical characteristic. The controller is programmed to use a first set of algorithms to process the signals received from the first set of field devices to determine if the measured values represented by the signals indicate that there might have been an influx of formation fluid into the subterranean well bore, and a second set of algorithms to process the signals received from the second set of field devices to determine if the measured values represented by the signals indicate that there might have been an influx of formation fluid into the subterranean well bore.

Abstract: A seal assembly for use in a pressure containment device for containing a fluid pressure in an annular space around a drill string whilst allowing the drill string to rotate in the pressure containment device. The seal assembly includes a seal comprising and an inner surface and a tubular body, and a wear sensor embedded in the tubular body. The wear sensor emits an alert signal when the inner surface of the seal has been worn away by a preset amount.

Abstract: A slip joint (10) having a tubular inner barrel (11b) and a tubular outer barrel (11a), the inner barrel (11b) lying at least partially within the outer barrel (11a), the slip joint further comprising a sealing assembly (12a), (12b), (12c) which is operable to provide a substantially fluid tight seal between two sealing surfaces comprising an interior surface of the outer barrel 11a and an exterior surface of the inner barrel (11b), the sealing assembly (12a), (12b), (12c) including an actuator (20) and a seal (46), the actuator (20) being movable to push the seal (46) into engagement with one of the sealing surfaces.

Abstract: A method of drilling a subterranean wellbore using a drill string including the steps of estimating or determining a reduced static density of a drilling fluid based on the equivalent circulating density of the drilling fluid in a section of the wellbore, providing a drilling fluid having substantially that reduced static density, introducing the drilling fluid having said reduced static density into the wellbore, and removing the drilling fluid from the wellbore via a return line.

Abstract: A drilling system including a riser, a pressure vessel, a source of pressurized gas, and a main flow line which extends from the riser to the pressure vessel, the pressure vessel having a liquid inlet port connected to the main flow line, a gas inlet port connected to the source of pressurized gas, a liquid outlet port located in a lowermost portion of the pressure vessel, and a gas outlet port located in an uppermost portion of the pressure vessel.

Abstract: A blow out preventer (BOP) for use in the drilling of a wellbore into a subterranean fluid reservoir and/or the production of fluid is provided. The BOP includes a housing having longitudinal axis and being divided into a first housing part and a second housing part, movement of the first housing part relative to the second housing part being prevented by fasteners, each fastener including a shaft which extends through a fastener receiving passage provided in the first housing part into a fastener receiving passage provided in the second housing part. The housing is further provided with fluid flow passages which extend from the first part of the housing to the second part of the housing, the fluid flow passages being interspersed between fastener receiving passages.

Abstract: A valve assembly comprising a body having a main passage, and a valve member which is located in the main passage and which is rotatable between an open position in which the main passage is substantially open, and a closed position in which the valve member substantially blocks the main passage, and an actuator which is movable generally parallel to the longitudinal axis of the main passage, the actuator being engaged with the valve member such that movement of the actuator generally parallel to the longitudinal axis of the main passage causes the valve member to rotate between its open and closed positions.

Abstract: A drilling system including a drill string (12) which extends into a borehole (10), and a well closure system which contains fluid in the annular space (16) in the borehole around the drill string, the well closure system having a side bore whereby controlled flow of fluid out of the annular space in the borehole around the drill string is permitted, the side bore being connected to fluid return line (28) which extends from the side bore to a fluid reservoir (34), there being provided in the fluid return line a valve (30a) which is operable to restrict flow of fluid along the fluid return line to variable extent, and a flow meter (32) operable to measure the rate of flow of fluid along the fluid return line, the flow meter being located between the valve and the side bore, wherein a filter (40) is provided between the flow meter and the side bore, the filter including a plurality of apertures which have a smaller cross-sectional area than the smallest fluid flow lines in the flow meter.

Abstract: An offshore universal riser system. A riser system includes a valve module which selectively permits and prevents fluid flow through a flow passage extending longitudinally through a riser string. An anchoring device releasably secures the valve module in the flow passage. A method of constructing a riser system includes the steps of installing the valve module in the flow passage, and installing at least one annular seal module in the flow passage. The annular seal module is operative to prevent fluid flow through an annular space between the riser string and a tubular string positioned in the flow passage. Drilling methods include injecting relatively low density fluid compositions into the annular space, and selectively varying a restriction to flow through a subsea choke in a drilling fluid return line. The riser string, including housings for the various modules and external control systems, is dimensioned for installation through a rotary table.

Abstract: An assembly of a drill pipe and a connector (10) for connecting a hose (50) to a side-bore (52) of a the drill pipe (54), the drill pipe (54) having a wall (54a) enclosing a main bore (54b), and the side-bore (52) extending through the wall (54a) from the main bore (54b) to the exterior of the drill pipe (54), the connector (10) comprising a hose connector body (12) which forms a first end of the connector (10) which is adapted to be connected to the hose (50), and a drill pipe connector body (14) which forms a second end of the connector (10) which is connected to the drill pipe (54), the connector (10) having an exterior surface and an interior surface which encloses a bore (20, 22) extending from the first end of the connector (10) to a second end of the connector (10), the drill pipe connector body (12) being provided with at least one bayonet connector formation (44) which extends from the exterior surface of the connector (10) generally radially outwardly relative to the bore (20, 22), the bayonet conne

Abstract: A valve assembly for use controlling flow of fluid into a drill pipe, the valve assembly having a valve body, a valve member and a valve seat, wherein a) the valve body has a main passage b) the valve member is movable between a closed position in which the valve member engages with a seat face of the valve seat to substantially prevent flow of fluid along the main passage, and an open position in which the valve member is spaced from the seat face, c) the valve seat is a separate part to the valve body.

Abstract: A pressure containment device for sealing around a tubular body comprising an actuator assembly and a seal assembly, the actuator assembly being operable to engage with the seal assembly to prevent significant rotation of the seal assembly with respect to the actuator assembly and to force the seal assembly into sealing engagement with a tubular body mounted in the pressure containment device, the seal assembly comprising a tubular seal sleeve having a radially inward portion made from a non-elastomeric polymer, and a radially outward portion made from an elastomer.

Abstract: A blowout preventer assembly comprising an annular blowout preventer having an annular packing unit and an actuator operable to reduce the internal diameter of the annular packing unit, wherein the assembly further comprises a stripping sleeve having a tubular elastomeric sleeve which in use is positioned generally centrally of the packing unit so that the packing unit surrounds at least a portion of the elastomeric sleeve.

Abstract: An offshore universal riser system may include a valve module which selectively permits and prevents fluid flow through a flow passage extending longitudinally through a riser string. An anchoring device may releasably secure the valve module in the passage. A method of constructing a riser system may include the steps of installing the valve module in the passage, and installing at least one annular seal module in the passage. The annular seal module may prevent fluid flow through an annular space between the riser string and a tubular string positioned in the passage. Drilling methods may include injecting relatively low density fluid compositions into the annular space, and selectively varying a restriction to flow through a subsea choke in a drilling fluid return line. The riser string, including housings for the various modules and external control systems, may be dimensioned for installation through a rotary table.