🔍 Key Concepts

• Function of conductor casing in offshore drilling from a MODU (Mobile Offshore Drilling Unit) • Relationship between sea level, sea floor (mudline), and rig/drill floor • How casing is positioned relative to the seabed to support the wellhead and later casing strings

💭 Think About

• First, picture the physical layout: MODU floating at sea level, drill floor well above water, and the seabed (sea floor) below. Where does the top of the first, large-diameter conductor pipe need to be for structural support? • Which choice would make it possible to attach the wellhead equipment and support the rest of the casing strings—at the rig floor, at the seabed, or somewhere in the water column? • Think about whether the conductor is mainly interacting with the sea surface, the sea floor (mudline), or the drill floor from a structural standpoint.

✅ Before You Answer

• Verify which reference point is correct: sea floor (mudline) vs sea level vs drill floor. • Check whether the conductor needs some exposed length at the seabed to connect wellhead equipment, or if it would be buried completely. • Confirm that the conductor’s top position should make sense for supporting the well structure and not simply be a depth measurement from the rig.