What connects the blowout preventer on the seabed to the drilling rig?

• A. Drillstring
• B. Marine Riser
• C. Casing
• D. Mud line

Answer: (B)

The link between the blowout preventer on the seabed and the drilling rig is the marine riser. It’s a long, heavy pipe that runs from the BOP stack on the seafloor up to the surface rig, creating a sealed path for drilling mud to circulate down through the drillstring and back up to the surface. This conduit keeps the well under control by maintaining the pressure relationship between bottom and surface while tools are lowered or raised. The drillstring passes through the riser, but the riser itself is the physical connection that ties the seabed BOP to the rig above. Casing is the lining installed in the well, and the mud line refers to the fluid return path, not the direct connection to the rig.