Abstract: A drilling riser system includes a plurality of interchangeable dockable modules having sealable hydraulic connections configured to connect to a module docking structure disposed in at least one specific segment of a drilling riser and to seal the hydraulic connections. Each of the interchangeable dockable modules includes at least one of an hydraulic termination or connection to an hydraulic device for each of a fluid conduit in fluid communication with the and at least one auxiliary line associated with the riser.

Abstract: A drilling riser system includes a plurality of interchangeable dockable modules having sealable hydraulic connections configured to connect to a module docking structure disposed in at least one specific segment of a drilling riser and to seal the hydraulic connections. Each of the interchangeable dockable modules includes at least one of an hydraulic termination or connection to an hydraulic device for each of a fluid conduit in fluid communication with the and at least one auxiliary line associated with the riser.

Abstract: A fluid transfer device for use in wellbore drilling includes at least one pressure vessel having a fluid port at a bottom thereof for entry and discharge of one of a working fluid or a power fluid and a fluid port at a top thereof for entry and discharge of the other of the power fluid or the working fluid. The pressure vessel has a barrier fluid between the power fluid and the working fluid. Valves are coupled to the power fluid port for selective introduction of the power fluid into the at least one pressure vessel. Valves are coupled to the working fluid port such that the working fluid is constrained to flow in only one direction.

Abstract: A method for marine wellbore drilling includes pumping drilling fluid through a drill pipe in a wellbore below a bottom of a drilling riser extending from proximate the bottom of the water to a drilling platform on the surface. Drilling fluid returning from the wellbore is discharged from a position proximate the bottom of the drilling riser into a fluid line extending from the position to the platform. Drilling fluid in the fluid line is pumped from a depth in the body of water shallower than the position of discharge of fluid from the riser and at which a column of fluid in the marine drilling riser at an elevation above an intake of a pump in the fluid line exerts a dynamic fluid pressure exceeding fluid pressure at the intake of the pump. The riser fluid level is selected to provide a selected fluid pressure in the wellbore.

Abstract: A device for control of return flow from a borehole, wherein drilling fluid is supplied from a drilling platform through a drill string disposed in a borehole includes an annulus formed between a pipe and the drill string. The annulus is in fluid communication with or forms part of a return path for the drill fluid. A choke is positioned in the annulus. An automatically operated annular seal element is disposed in the pipe above the drill fluid return path. The automatically operated annular seal element is configured to close the annulus to fluid communication when at least one of a predetermined fluid flow rate in the pipe and a predetermined pressure differential across the automatically operated annular seal element is reached.

Abstract: A device for control of return flow from a borehole, wherein drilling fluid is supplied from a drilling platform through a drill string disposed in a borehole includes an annulus formed between a pipe and the drill string. The annulus is in fluid communication with or forms part of a return path for the drill fluid. A choke is positioned in the annulus. An automatically operated annular seal element is disposed in the pipe above the drill fluid return path. The automatically operated annular seal element is configured to close the annulus to fluid communication when at least one of a predetermined fluid flow rate in the pipe and a predetermined pressure differential across the automatically operated annular seal element is reached.

Abstract: A pump module for a drilling riser includes at least one pump mounted to a frame, the frame including features to couple the frame to a segment of riser. A fluid inlet is affixed to the frame. The fluid inlet is in fluid communication with an intake of the at least one pump. The fluid inlet has features to make fluid tight hydraulic connection to a fluid outlet of the riser segment when the frame is coupled thereto.

Abstract: A method for inhibiting an explosive atmosphere in a wellbore drilling system, including a riser (12) connected to a wellbore above a top thereof wherein the riser has a fluid outlet (17) below a surface of a body of water in which the wellbore is drilled, and wherein the fluid outlet is connected to a subsea pump to return drilling fluid to a drilling platform on the water surface and wherein a space in the riser (12) above the drilling fluid level filled with air includes pumping drilling fluid into a drill string (15) extending from the drilling platform into the wellbore. Fluid (27) is introduced proximate an upper end of the riser (12). A rate of introducing the fluid (27) is selected to inhibit an explosive atmosphere in the space in the riser above the drilling fluid level. The subsea pump to remove fluid from the riser outlet is operated at a rate selected to maintain the fluid level or to maintain a selected wellbore pressure.

Abstract: There is provided a device and method for control of return flow from a borehole (18) where drill fluid is supplied from a surface rig (16) via a multi section drill string (4) to a bottom hole assembly (18), the drill pipe sections (6) having tool joints (8) that include an enlarged outer diameter portion (9), and where an annulus (12) is formed between a pipe (2) and the drill string (4), and where the annulus (12) is in fluid communication with or forms part of a return path (40) for the drill fluid, and where a choke (1) is positioned in the annulus (12), and where the length (L) of the choke (1) exceeds the distance (M) between the enlarged outer diameter portion (9) of two adjacent tool joints (8).

Abstract: Boost system and method for dual gradient drilling where a marine riser (1) has a mud return line (14) connected at a first connection position (18) below the lowest foreseeable mud level (12) in the marine riser (1), and where a mud return pump (16) is connected to the mud return line (14), and where a recirculation line (20) that has a recirculation pump (22), is connected to the marine riser (1) at a second connection position (24) below the lowest foreseeable mud level (12) in the marine riser (1), and at a third connection position (26) on the marine riser (1) below said second connection position (24).

Abstract: There is provided a device and method for control of return flow from a borehole (18) where drill fluid is supplied from a surface rig (16) via a multi section drill string (4) to a bottom hole assembly (18), the drill pipe sections (6) having tool joints (8) that include an enlarged outer diameter portion (9), and where an annulus (12) is formed between a pipe (2) and the drill string (4), and where the annulus (12) is in fluid communication with or forms part of a return path (40) for the drill fluid, and where a choke (1) is positioned in the annulus (12), and where the length (L) of the choke (1) exceeds the distance (M) between the enlarged outer diameter portion (9) of two adjacent tool joints (8).

Abstract: A method for inhibiting an explosive atmosphere in a wellbore drilling system, including a riser (12) connected to a wellbore above a top thereof wherein the riser has a fluid outlet (17) below a surface of a body of water in which the wellbore is drilled, and wherein the fluid outlet is connected to a subsea pump to return drilling fluid to a drilling platform on the water surface and wherein a space in the riser (12) above the drilling fluid level filled with air includes pumping drilling fluid into a drill string (15) extending from the drilling platform into the wellbore. Fluid (27) is introduced proximate an upper end of the riser (12). A rate of introducing the fluid (27) is selected to inhibit an explosive atmosphere in the space in the riser above the drilling fluid level. The subsea pump to remove fluid from the riser outlet is operated at a rate selected to maintain the fluid level or to maintain a selected wellbore pressure.

Abstract: A fluid transfer device for use in wellbore drilling includes at least one pressure vessel having a fluid port at a bottom thereof for entry and discharge of a working fluid and a fluid port at a top thereof for entry and discharge of a power fluid. The pressure vessel has no physical barrier between the power fluid and the working fluid. Valves are coupled to the power fluid port for selective introduction of the power fluid into the at least one pressure vessel. Valves are coupled to the working fluid port such that the working fluid is constrained to flow in only one direction.

Abstract: A pump module for a drilling riser includes at least one pump mounted to a frame, the frame including features to couple the frame to a segment of riser. A fluid inlet is affixed to the frame. The fluid inlet is in fluid communication with an intake of the at least one pump. The fluid inlet has features to make fluid tight hydraulic connection to a fluid outlet of the riser segment when the frame is coupled thereto.

Abstract: A fluid transfer device for use in wellbore drilling includes at least one pressure vessel having a fluid port at a bottom thereof for entry and discharge of a working fluid and a fluid port at a top thereof for entry and discharge of a power fluid. The pressure vessel has no physical barrier between the power fluid and the working fluid. Valves are coupled to the power fluid port for selective introduction of the power fluid into the at least one pressure vessel. Valves are coupled to the working fluid port such that the working fluid is constrained to flow in only one direction.

Abstract: A method for the pressure regulation of a well (1) extending into a well formation (2) and being drilled from a drilling vessel at sea, the well (1) including a blowout preventer (10) on the seabed (12) and a riser (14) extending from the blowout preventer (10) up to the vessel, and the return path (8, 14, 20) of a drilling fluid (24) being provided with a rotatable surface seal (22) sealingly surrounding a drill string (4), the rotatable surface seal (22) being arranged to seal against a pressure difference between the surroundings and the return path (8, 14, 20), and there being arranged, at the rotating surface seal (22), a closable drilling-fluid outlet (28), the method including: arranging a pump inlet (32) from the return path (8, 14, 20) under water; connecting a pump (30) to the return path (8, 14, 20), the pump (30) being connected to a pressure pipe (34) discharging on the vessel; monitoring the drilling-fluid pressure; and controlling the pumping rate through the pump (30) to maintain a substantial