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To meet the ever-increasing needs for improved efficiency, cost control and safety enhancement in (ultra-)deepwater well construction, a novel drillship design has been developed that has been outfitted with a unique, versatile and highly automated drilling package. In particular, a new Dual Multi-Purpose Tower (DMPT) design was developed. It is similar to an earlier design employed on four drill ships currently in service with a major international oil company (IOC) in that it has no V-door limitation and features two well centers, enabling concurrent operations. Lessons learned from the four drill ships have been incorporated in the new vessel design. Careful study of deepwater drilling-the-well-on-paper (DWOP) information shows that the new DMPT drilling system and vessel design have the capability to reduce drill times by 20-25% through reduction of flat times, increased tripping speeds by use of true automation, running 180ft stands of drill pipe, running 22″ 180ft casing in open water, running of 150ft risers, dual rotary hang-off tables and doing as much as possible off critical paths. The vessel design itself was optimized with both drilling and completion operations in mind, and is prepared for future technologies, eliminating costly and time consuming upgrades. Design efforts aimed at reduced maintenance of equipment and reduced downtime led to additional cost savings and the vessel uses significantly less fuel, thereby reducing consumables and environmental impacts. The vessel can hold 30000mt variable deck load (VDL), can operate in waters up to 4,000 m, can store and run two 20k BOPs and is inherently prepared for managed pressure drilling (MPD) and dual gradient drilling (DGD) operations. A large, unobstructed flat workdeck from fore to aft of the vessel provides over 4,500 m2 of safe, open deck space for drilling and completion activities. The new drilling system, combined with the additional savings in fuel, maintenance downtime, and increased safety afforded by the optimized vessel design may yield total well delivery savings in excess of 30%. In this paper, pertinent details are shared about the vessel and drilling system designs, as well as how these designs facilitate the indicated time and cost savings. |
