Case study: RRS Sir David Attenborough (part 1 of 3) The RRS…
Compact Drillship Design
The Stena DrillSLIM drillship design is based on Houlder’s 150m hull form developed to reduce motions and enhance seakeeping. The design gives operators the ability to drill a 15,000ft slim well in 7,500ft water depth. It features a high pressure riser with surface and subsea BOPs and is well placed to drill complete wells or deliver Well Intervention.
The solution is compact and flexible and works at substantially lower build and operating costs than the latest high specification rigs. It does this without compromising on the level of drilling technology delivered.
Main features of the drillship design include –
The slim-hole drilling package is a single mast with a ram type hoisting system and a top drive and double joints of Range 2 drillpipe. The dead line will incorporate the drill string motion compensator.
The mast has a hydraulic racking system with setback capacity for 22,000ft of drillpipe and 1,000ft of drill collars.
The skidding system below the substructure provides handling and storage for the 13.5/8″ Subsea Emergency disconnect package ,the Lower 13.5/8″ BOP , 13.5/8″ Upper BOP and up to 4 horizontal or conventional subsea trees.
The Well Control Equipment consists of a Subsea Lower BOP including a LMR and emergency disconnect (LBOP), an Upper BOP (UBOP) and a diverter system.
The LBOP consists of 1 hang-off ram, 2 blind shear rams and an LRP with a hydraulic disconnect package.
The riser consists of 7,500ft of 16.3/4″ x 10,000psi High Pressure riser with one kill/choke line, one booster line and two hydraulic lines.
The crane at the aft of the vessel is 120T knuckle boom crane capable of limited underwater engineering activities (change out manifold and trees etc) with two further 30T knuckle boom cranes to transfer loads for the purpose of handling riser joints.
The drillship design demonstrates Houlder’s capability to understand the complex requirements of modern drilling and develop vessel concepts for the energy sector.