With operators drilling more challenging deepwater programs, the demand for dynamically positioned drillships with versatile, multifunctional capabilities has grown accordingly.

Several years ago Ensco set out to configure and deploy a drillship with features to enhance operators’ drilling programs in ultradeepwater environments. It linked up with Samsung Heavy Industries (SHI)—the world’s largest drillship builder—to develop state-of-the-art vessels with a range of capabilities adaptable to each operator’s specific requirements.

The resulting Samsung 96k DWT design has been used for several units from the ENSCO DS-3 to the ENSCO DS-7, with these vessels equipped with advanced technological features for drilling and completing deepwater wells including DPS-3 certified dynamic positioning, six-ram 15,000-psi BOPs, enhanced offline capability, 2.5 MMlb hook load on main rotary, 6,000-bbl active and 7,400-bbl reserve dual-fluid systems, 165-mt active heave subsea crane, significant storage and deck space and accommodations for up to 200 people.

The ongoing trend to drill even deeper and more complex reservoirs, however, means that operators need even more advanced technology. Ensco again collaborated with SHI to develop a next-generation drillship based on the proprietary Samsung GF 12000 design, which it chose for its latest line of ultradeepwater units, the ENSCO DS-8, ENSCO DS-9 and ENSCO DS-10.

The Samsung GF 12000 “Green Future” design offers numerous improvements for higher operating efficiency. Primary to these capabilities are a focus on redundant equipment—such as riser handling, pipehandling and BOPs—throughout the drilling systems to eliminate single-point failures.

The 165-ton active heave compensating subsea construction crane enables deployment of subsea production equipment without interference with ongoing drilling operations and allows the handling of items too large or awkward to fit through the moonpool. Retractable thrusters significantly reduce out-of-service maintenance and allow easy access to ports worldwide. Ensco also said that, due to hull form improvements and the ability to retract the three forward thrusters while transiting, customers can save on fuel relative to older drillships.

Additional features include enhanced safety and environmental features; dynamic positioning capabilities; and drilling and completion functionality such as below-main-deck riser storage, triple fluid systems, offline conditioning capability, and enhanced client and third-party facilities.

Ensco said these latest-generation rigs have earned it multiyear contracts with major customers over other drillship designs. Ensco has, for example, been awarded a five-year contract with Total for the ENSCO DS-8 and a three-year contract with ConocoPhillips for the ENSCO DS-9, which has enhanced features such as managed pressure drilling and riser gas handling. ENSCO DS-10 will also have a seven-ram 15,000-psi BOP.

Vessel Facts

Sector: Deepwater Drilling

Owner: Ensco

Names: Ensco DS-8, 9 & 10

Vessel Design: Samsung GF12000

Yard Built: SHI

First Operations: fourth-quarter 2015 onward

Size (length/beam): 230 m by 38 m (754.5 ft by 124.6 ft)

Max Water Depth: 3,658 m (12,000 ft)

Max Drilling Depth: 2,192 m (40,000 ft)

Transit Speed: 10 knots

BOP: 15,000 psi, 6 or 7 Ram

Operating/Regional Arena: Worldwide deepwater

Classification: ABS A1E DP3

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