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: An apparatus for continuous circulation drilling comprising a tubular body having a main passage extending along a longitudinal axis of the tubular body from a first end of the tubular body to a second end of the tubular body, a side passage and a control passage, the side passage and control passage both extending through the tubular body into the main passage, the tubular body containing a valve assembly which is operable to close the main passage when the side passage is open and to close the side passage when the main passage is open, the assembly further comprising a hydraulic connector which is operable to clamp around the tubular body, the connector comprising a housing with an interior surface which is provided with first and second grooves which, when the connector is clamped around the tubular body, each form a channel which extends in continuous loop around the exterior of the tubular body, there being at least one passage extending through the housing from an exterior surface of the housing into e

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 control apparatus for use in controlling the fluid pressure in a borehole during drilling of the borehole, the apparatus including an inlet suitable for connection to a pump, a main outlet suitable for connection to a drill pipe, and an overflow outlet suitable for connection to a fluid reservoir, the inlet being connected to the main outlet by a main flow conduit, and the overflow outlet being connected to the main flow conduit by means of an overflow conduit, wherein the overflow conduit is provided with a pressure regulator by means of which the pressure of fluid in the main flow conduit may be maintained at or around a predetermined pressure value.

Abstract: A drilling system including a riser, a pressure vessel, a source of pressurised 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 pressurised 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: An apparatus for degassing drilling fluid comprising a primary separator and a secondary separator, the primary separator comprising a vessel body having an inlet port, a liquid outlet port located at a lower end of the vessel body, and a gas vent port located at an upper end of the vessel body, the secondary separator having an inlet port which is connected to the gas vent port of the primary separator, a gas outlet port, and a liquid outlet port which is connected to the interior of the vessel body of the primary separator via a liquid return line.

Abstract: A control apparatus for use in controlling the fluid pressure in a borehole during drilling of the borehole, the apparatus including an inlet suitable for connection to a pump, a main outlet suitable for connection to a drill pipe, and an overflow outlet suitable for connection to a fluid reservoir, the inlet being connected to the main outlet by a main flow conduit, and the overflow outlet being connected to the main flow conduit by means of an overflow conduit, wherein the overflow conduit is provided with a pressure regulator by means of which the pressure of fluid in the main flow conduit may be maintained at or around a predetermined pressure value.

Abstract: A pressure containment device for containing pressure in an annulus around a tubular body, the device comprising a housing having an axis and a passage extending generally parallel to the housing axis, and a seal assembly comprising a seal located in the housing to surround and enter into sealing engagement with a tubular body extending along the passage, wherein the housing is provided with a returns outlet port, an injection port, and an overflow outlet port, all of which extend through the housing from the exterior of the housing into the passage, the injection port being located between the returns outlet port and a first end of the seal, and the overflow outlet port being located adjacent a second, opposite end of the seal, and thus being separated from the injection port by the seal.

Abstract: A method of drilling a subterranean wellbore using a drill string comprising the steps of: a. injecting a drilling fluid into the well bore via the drill string and removing said drilling fluid from an annular space around the drill string (the annulus) via an annulus return line, b. oscillating the pressure of the fluid in the annulus, c. determining the wellbore storage volume and wellbore storage coefficient for each fluid pressure oscillation, d. using the wellbore storage volume and wellbore storage coefficient to determine the proportion by volume of gas and proportion by volume of liquid in the annulus during that pressure oscillation.

Abstract: A blowout preventer assembly comprising a blowout preventer and control apparatus, the blowout preventer comprising a housing a sealing element and a fluid pressure operated actuator mounted in the housing, the actuator 18 dividing the interior of the housing into two chambers, namely an open chamber and a close chamber, substantially preventing flow of fluid between the two chambers, and being movable, by means of the supply of pressurized fluid to the close chamber, to urge the sealing element into sealing engagement with a drill pipe extending through the blow out preventer, the control apparatus including a close line which extends from the exterior of the housing to the close chamber, and a source of pressurized fluid which is connected to the close line, wherein the source of pressurized fluid is located adjacent to the housing.

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 drilling system (10) including a drill string (13) which extends from a floating drilling rig to a well bore, and a tubular riser (12) which surrounds at least part of the portion of the drill string (13) between the well bore and drilling rig, the riser (12) having a telescopic joint (20) between a first tubular portion and a second tubular portion of the riser, the first tubular portion extending down to a well head at the top of the well bore and the second tubular portion extending up towards the drilling rig, the telescopic joint (20) comprising an inner tube part (20b) which is mounted within an outer tube part (20a), the drilling system (10) further including a riser closure device (26) which is mounted in the second tubular portion of the riser (12) and which is operable to provide a substantially fluid tight seal between the riser (12) and the drill string (13) whilst permitting the drill string (13) to rotate relative to the riser (12).

Abstract: A method of drilling a subterranean well bore comprising, monitoring the well bore for influx of formation fluid into the well bore, and, on detection of an influx, a) stopping any pump pumping fluid into the well bore, b) operating a first blow out preventer so that it closes within a first period of time, c) operating a second blow out preventer so that it closes within a second period of time, the second blow out preventer being located below the first blow out preventer, the second period of time being longer than the first period of time, d) circulating the influx out of the well bore via a flow line extending from below the second blow out preventer.

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 dosed positions.

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 borehole comprising: a) pumping a drilling fluid down a drillstring (12), the drillstring (12) having a bit (14) at an end thereof, b) rotating the drillstring (12) about its longitudinal axis so that the bit forms a borehole (10) in the ground, the method further comprising the steps of: c) determining a desired drilling fluid flow rate range d) determining the desired upper and lower limits of the fluid pressure at the bottom of the wellbore (the BHP); e) determining the viscosity of drilling fluid which will maintain the BHP within the range set by the upper and lower BHP limits over the entire or the majority of the required drilling flow rate range; f) adjusting the composition of a drilling fluid to bring the drilling fluid to the viscosity calculated in step e above.

Abstract: A method of drilling a subterranean well bore using a tubular drill string described. One embodiment of the method includes the steps of injecting a drilling fluid into the well bore via the drill string and removing said drilling fluid from an annular space in the well bore around the drill string via a return line. The method can also include oscillating the pressure of the fluid in the annular space in the well bore, and monitoring the rate of flow of fluid along the return line.

Abstract: A blow out preventer (BOP), in particular a new configuration of BOP which may have a smaller outer diameter for a given operating force than conventional BOPs comprises a housing which has a longitudinal axis and which is divided in a first housing part (14a) and a second housing part (14b), movement of the first housing part relative to the second housing part being prevented by fasteners (16), 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 being further provided with fluid flow passages (44) 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. In one embodiment of the invention, three annular BOPs according to this design are integrated to form a stack.