We can divide the new drillships designs into three main groups:
1. Ships with no oil storage capability, generally intended for exploration drilling.
2. Ships with a limited oil storage capability (up to about 150,000 bbls) and equipped for exploration and development drilling.
3. Ships with large oil storage (400,000 bbls) and equipped for exploration and development
drilling.
The GLOMAR CR LUIGS belongs to the second category. She is built with void spaces designed for oil storage and slop tanks, and can thus be adapted, if needed for extended well testing or early production. The vessel is the smallest of those attempting to combine both drilling and storage functions, and this has complicated design and construction process to a certain extent.
GLOMAR CR LUIGS is a dynamically-positioned monohull drillship, capable of drilling a 35,000ft well in waters up to 3660m depth (12,000 feet). She is delivered initially outfitted for operations in 9000ft (2740m) of water. The vessel is marketed as having a variable load capability of 26,000 tonnes while drilling, and 44,000ft2 (4088m2 ) of dedicated equipment storage for tubulars, third party equipment etc. A key feature of the vessel is the attention, which has been paid to the handling of major drilling components, particularly those operations that are affected by the depth of water.
The equipment that has been provided to assist the time consuming elements of deepwater operations includes the following:
• powered riser storage system
• powered drill pipe and collar racking system
• powered and stabilised BOP handling system for fully assembled BOPs and subsea trees.
Conceptually, the vessel design aims to keep the tubular storage (riser, casing, drillpipe) and drilling machinery out of the main hull as far as possible. This means that there is a considerable amount of structure erected above the upper deck to support and contain these items. On the other hand, the interface between the drilling and ship systems is minimised