Abstract: There is described a technique for drilling and controlling the fluid pressure of a borehole (2, 102) during drilling of the borehole. In embodiments of the invention, drill pipe (5) may be arranged in said borehole, the pipe being configured to provide drilling fluid in the borehole. Sealing means (14, 18, 114, 118) may be provided and arranged to sealingly abut an outer surface of the drill pipe to separate said drilling fluid in the borehole on a first side of the sealing means from a column of fluid on a second side of the sealing means. Furthermore, a subsea pump arrangement (12, 112) may be arranged under a sea surface where it receives a flow of said drilling fluid from the borehole.

Abstract: A system is provided for passing matter in a flow passage of an oil and/or gas drilling or production installation, in particular for passing trash or drill cuttings in a drilling fluid return line. The system includes at least two valves arranged in series in the passage; and a control device configured to selectively or sequentially actuate the at least two valves, such that the material is allowed to pass the at least two valves in the passage. A method is also provided for passing trash or drill cuttings in a drilling fluid return line.

Abstract: A gate valve is provided for returned drilling mud pressure control and/or well killing. The gate valve includes a flow passage; and a gate member movable for intersecting the flow passage. The gate member includes a gate port which extends from one face to an opposite face of the gate member and is alignable with the flow passage for allowing material in the flow passage to pass through the gate member, and a groove or recess is provided in an inner wall of the gate port, the groove or recess extending from the one face to the opposite face of the gate member. A method is provided for returned drilling mud pressure control and/or well killing, and uses of a gate valve.

Abstract: There is described a technique for drilling and controlling the fluid pressure of a borehole (2, 102) during drilling of the borehole. In embodiments of the invention, drill pipe (5) may be arranged in said borehole, the pipe being configured to provide drilling fluid in the borehole. Sealing means (14, 18, 114, 118) may be provided and arranged to sealingly abut an outer surface of the drill pipe to separate said drilling fluid in the borehole on a first side of the sealing means from a column of fluid on a second side of the sealing means. Furthermore, a subsea pump arrangement (12, 112) may be arranged under a sea surface where it receives a flow of said drilling fluid from the borehole.

Abstract: A system is provided for passing matter in a flow passage of an oil and/or gas drilling or production installation, in particular for passing trash or drill cuttings in a drilling fluid return line. The system includes at least two valves arranged in series in said passage; and a control device configured to selectively or sequentially actuate said at least two valves, such that the material is allowed to pass said at least two valves in the passage. A method is also provided for passing trash or drill cuttings in a drilling fluid return line.

Abstract: A gate valve is provided for returned drilling mud pressure control and/or well killing. The gate valve includes a flow passage; and a gate member movable for intersecting the flow passage. The gate member includes a gate port which extends from one face to an opposite face of the gate member and is alignable with the flow passage for allowing material in the flow passage to pass through the gate member, and a groove or recess is provided in an inner wall of the gate port, the groove or recess extending from the one face to the opposite face of the gate member. A method is provided for returned drilling mud pressure control and/or well killing, and uses of a gate valve.

Abstract: A riserless mud recovery system including a mud return line secured by an anchor is disclosed. Some system embodiments for drilling a well bore in an offshore location having a water surface and a subsea formation include an offshore structure positioned on a platform at a water surface, a drill string for forming the well bore suspended from the offshore structure, a drilling fluid source on the platform for supplying drilling fluid through the drill string, a suction module for collecting the drilling fluid emerging from the well bore, a return pipe coupled to the suction module, a pump for receiving the drilling fluid from the suction module and pumping the drilling fluid through the return pipe to a location at the water surface, and an anchor for securing the return pipe, where the anchor is coupled to the return pipe and the subsea formation.

Abstract: Systems and methods for drilling a well bore in a subsea formation from an offshore structure positioned on a water surface with a drill string that is suspended from the structure and includes a bottom hole assembly adapted to form a top hole portion of the well bore. A drilling fluid source on the offshore structure supplies drilling fluid through the drill string to the bottom hole assembly where the drilling fluid exits from the bottom hole assembly during drilling and returns up the well bore. A suction module is disposed at the sea floor and collects the drilling fluid emerging from the well bore. A pump module is disposed on a return line, which is in fluid communication with the suction module, at a position below the water surface and above the sea floor. The pump module is operable to receive drilling fluid from the suction module and pump the drilling fluid through the return pipe to the same offshore structure or a different offshore structure.

Abstract: A riserless mud recovery system including a mud return line secured by an anchor is disclosed. Some system embodiments for drilling a well bore in an offshore location having a water surface and a subsea formation include an offshore structure positioned on a platform at a water surface, a drill string for forming the well bore suspended from the offshore structure, a drilling fluid source on the platform for supplying drilling fluid through the drill string, a suction module for collecting the drilling fluid emerging from the well bore, a return pipe coupled to the suction module, a pump for receiving the drilling fluid from the suction module and pumping the drilling fluid through the return pipe to a location at the water surface, and an anchor for securing the return pipe, where the anchor is coupled to the return pipe and the subsea formation.

Abstract: Systems and methods for drilling a well bore in a subsea formation from an offshore structure positioned on a water surface with a drill string that is suspended from the structure and includes a bottom hole assembly adapted to form a top hole portion of the well bore. A drilling fluid source on the offshore structure supplies drilling fluid through the drill string to the bottom hole assembly where the drilling fluid exits from the bottom hole assembly during drilling and returns up the well bore. A suction module is disposed at the sea floor and collects the drilling fluid emerging from the well bore. A pump module is disposed on a return line, which is in fluid communication with the suction module, at a position below the water surface and above the sea floor.