This paper describes a new approach on how to automate, not mechanize, the drilling equipment on mobile offshore drilling units. Traditionally the drilling industry builds further on the existing equipment. For true automation a radical new approach is necessary: Equipment is no longer the core, automation is the core. The equipment is designed around the automation. Because of the automation less people are required on the drill floor, increasing the safety. Further the operations are more efficient, since the system can perform at consistent high speeds.

Based on the auto-tripping technology utilized on Huisman's LOC400 land rigsthe Noble Globetrotter II, a HuisDrill drill ship design, was equipped with and tested with an auto-tripping system. During the design of this auto-tripping system it was discovered that the existing equipment was the limiting factor. Therefore, a new drilling equipment set was designed with automation as the core. This resulted in a system which is different than traditional systems.

The Dual Multi Purpose Tower (DMPT) enhances safety during auto-tripping by physically separating the drilling side of the tower from the construction side of the tower. On the drilling side of the tower the drill floor is unmanned during auto-tripping while on the construction side people can continue to perform various tasks safely and unencoumbered by the auto-tripping operation. The DMPT functions as a safety barrier between the two floors. People are not working on a drill floor where also automated machinery is moving.

Furthermore the stiff box structure of the DMPT provides a good foundation for the vertical pipe handling machines. Simple and identical motions of various handling devices enable automation. The handling devices are outfitted with easy to exchange tool assemblies for various functions. The following tool assemblies are available: pipe grippers for a range of pipes, power tongs, horizontal-to-vertical tools, special tools for completions, man-riding baskets, etcetera.

In addition, a tubular database is integrated in the control system. The database stores various data about the tubulars (length, type, running hours, etcetera) and keeps track of the position of each of the tubulars in the setback or in the well center. With this system it is exactly known how many tubulars are in the hole, what the total length of the drill string is and whether there are unshearable elements in the BOP. The driller no longer has to keep track with a paper tally list.

The utilization of the tower's handling devices enables more efficient drilling and completions operations. A constant high tripping speed can be achieved by automating the handling devices and, since less or no people are required on the drill floor, the safety is greatly increased. The auto-tripping/drilling further enables other automation innovations: for example automated drilling, MPD, dual gradient drilling in combination with input from downhole sensors.

In addition to the above, the riser running speed can be significantly increased by handling unconventionly longer risers. Due to the open characteristics of the DMPT (no-V-door limitations) and the large below deck space in the vessel, risers can be stored and upended with lengths up to 150ft. Additionally, a large workshop is provided inside the hull with space for maintenance and inspection of risers on-board the vessel

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