User:Andyminicooper/Marine Drilling Riser
A Marine drilling riser is a jointed pipe assembly passing through the water column, and through which drilling operations are performed from an offshore drilling rig.
The marine riser provides a conduit for access to a wellhead located on the sea floor; the top of a subsea well.
The marine riser for a floating drilling vessel will typically be connected to a subsea Blowout preventer (BOP) attached to the wellhead. In this configuration the marine riser is pressure rated for pressures lower than the maximum wellhead pressure as the BOP provides pressure control.
When a fixed drilling facility is present, the marine riser may connect directly to the wellhead, and the blowout preventor will be located at the surface. In this configuration, the riser must be pressure rated for the well operations.
Configuration[edit]
The marine riser is normally provided in short sections (joints) with connectors at each end, and joined together vertically to
The marine riser can be configured of a number of parallel elements; Main tube - provides access to the well and must be larger diameter than the well and tools required to be deployed, usually the structural element. Choke & Kill lines - high pressure lines for circulating drilling mud to the subsea BOP Mud booster line - line to prvide additional mud to the base of the riser to maintain return fluid velocity Umbilical - control and power lines for the subsea BOP Hydraulic line - additional hydraulic power supply to the subsea BOP
Where a surface BOP is used, most of these additional auxilliary lines are not needed.