It is well known that the rise of global energy demand could not otherwise be met without the aid of offshore drilling innovations that are unlocking oil and natural gas resources that previously were thought as inaccessible. Today Semi-submersibles i.e. oil platform rigs and Drill-ships are the two major types of these innovations with respect to deepwater oil drilling.
Offshore Drilling and Production vessels or drill-ships are industrial vessels primarily utilized in the petroleum industry for exploration and exploitation of subsea resources and are the continuation of Floating Production, Storage and Offloading vessels (FPSOs). As of today the total fleet of drill-ships comprises of 59 vessels in operation with another 91 being contracted or under construction, the vast majority of which in South Korea.
A drill ship is an adaptation of a standard seagoing ship of mono-hull form with the addition of a substructure with a moon pool and cantilevers from which the drilling operations are carried out. Sophisticated equipment such as top-drive systems for the derrick and expanded high-pressure mud-pump systems are also included in this arrangement. A typical drillship of the latest generation is on average over 200 meters long and 40 meters wide, weighs about 60,000 tonnes and has the capability of drilling up to 40,000 feet of total depth in waters and up to 12,000 feet deep. These vessels are also equipped with advanced dynamic positioning systems by means of powerful thrusters that allow the unit to be kept steady above the drill centre so that the vessel maintains a close relationship with the bore hole in the seabed. Their living quarters can accommodate up to 200 people.
One state-of-the-art drill-ship is the “Discoverer Enterprise” owned by the world’s largest drilling contractor “Transocean” and features a new re-engineered offshore drilling technique, namely “dual-activity drilling”, which compared to a conventional oil rig can reduce the cost of constructing offshore development well by up to 40 per cent with significant operational savings. Such a modern drillship may cost about 640 million dollars to build and can earn up to $800,000 a day.
Recent prices of crude oil in the range of $60 to $80 per barrel provide the incentive for the billions of dollars in investments needed to locate and develop new oil and gas sources in deep waters. As long as oil prices remain in this range or higher, the oil industry will continue to spend the hundreds of millions of dollars it costs to design and build these highly capable drill ships.

By Xenofon Varias,
AUEB Energy & Sustainability Club
Executive Member