Abstract: This disclosure includes flow spool riser segment assemblies that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the flow spool connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes auxiliary-line riser segment assemblies (e.g., with isolation units) that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the auxiliary lines connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes flow spool riser segment assemblies that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the flow spool connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes flow spool riser segment assemblies that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the flow spool connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes auxiliary-line riser segment assemblies (e.g., with isolation units) that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the auxiliary lines connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes auxiliary-line riser segment assemblies (e.g., with isolation units) that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the auxiliary lines connected (e.g., without welding) below the rotary.

Abstract: A riser assembly is disclosed comprising: a main tube; two flanges coupled to the main tube, each flange comprising: a central lumen configured to be in fluid communication with the main tube; at least one choke/kill hole configured to receive a choke/kill line; at least one booster hole configured to receive a booster line; and a plurality of bolt holes, each bolt hole comprising a tapered portion and a dowel slot, where each bolt hole is configured to receive a nut, a bolt, and a dowel. In certain embodiments, riser strings comprising at least two riser assemblies coupled to each other are disclosed.

Abstract: This disclosure includes flow spool riser segment assemblies that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the flow spool connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes auxiliary-line riser segment assemblies (e.g., with isolation units) that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the auxiliary lines connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes auxiliary-line riser segment assemblies (e.g., with isolation units) that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the auxiliary lines connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes flow spool riser segment assemblies that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the flow spool connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes auxiliary-line riser segment assemblies (e.g., with isolation units) that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the auxiliary lines connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes auxiliary-line riser segment assemblies (e.g., with isolation units) that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the auxiliary lines connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes auxiliary-line riser segment assemblies (e.g., with isolation units) that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the auxiliary lines connected (e.g., without welding) below the rotary.

Abstract: This disclosure includes flow spool riser segment assemblies that are suitable for managed pressure drilling (MPD) and that can be lowered (e.g., when connected to other riser segment assemblies) through a rotary of a drilling rig. Some embodiments are configured to have portions of the flow spool connected (e.g., without welding) below the rotary.

Abstract: A riser assembly is disclosed comprising: a main tube; two flanges coupled to the main tube, each flange comprising: central lumen configured to be in fluid communication with the main tube; at least one choke/kill hole configured to receive a choke/kill line; at least one booster hole configured to receive a booster line; and a plurality of bolt holes, each bolt hole comprising a tapered portion and a dowel slot, where each bolt hole is configured to receive a nut, a bolt, and a dowel. In certain embodiments, riser strings comprising at least two riser assemblies coupled to each other are disclosed.