PNG 301
Introduction to Petroleum and Natural Gas Engineering Drill Ships


As the name implies, a Drill Ship is a sea-going ship that is specifically modified to perform deep water drilling operations. They are equipped with an on-board drilling rig that sits above a Moon Pool (a hole in the ship’s structure from the main deck through to the hull). The Moon Pool (or “Wet Deck”) allows drill pipe to extend from the rotary system of the drilling rig, through the structure of the ship, through the hull, into the water to the sea floor, and into the wellbore. Figure 8.13 provides a picture of a drill ship.

Drill ships are used for deepwater drilling in regions with little onshore logistical support. Drill ships can typically store large quantities of supplies which allows for their use in more remote regions. Consequently, drill ships are often used for exploration well drilling in remote, deep water locations.

Figure 8.13: Drilling Ship, Discoverer Enterprise
Source: 2b1st Consulting - Drill Ship

Like semi-submersible drilling rigs, drill ships are kept on location during drilling operations with the use of a system of dynamic positioning thrusters. As previously discussed, however, semi-submersible drilling rigs are considered to be a more stable drilling platform than drill ships.