NEW RIG DESIGNS

Shell and Frontier joint venture to build the “Bully” drillship

Shell EP Offshore Ventures Ltd. and Frontier Drillships Ltd., a subsidiary of Frontier Drilling, signed a deepwater/arctic drillship Joint Venture (JV) agreement. Under the agreement, Shell and Frontier will build and roll out a new drillship concept, known as the “Bully” rig. The drillship design sets a new standard and offers a flexible, smaller but highly capable vessel suited for deepwater and arctic drilling, while reducing the construction and operational costs compared to newbuild drilling rigs of similar capability. The Shell/Frontier JV expects to deliver the first Bully rig to the Gulf of Mexico by early 2010. It will be operated by Frontier on behalf of the JV under a separate management services contract.

The rig design was developed by Frontier in cooperation with Shell’s deepwater experts. The innovative design offers flexibility and rapid deployment, setting the standard for technologically advanced vessels. A new development in ultra-deepwater drilling is the use of a surface BOP with a slimline, pressurized riser. GustoMSC developed the PRD 12,000-DP drillship with this technology incorporated. The conventional PRD 12,000-DP vessel is able to drill in water depths up to 12,000 ft using a surface BOP stack and slimline riser, while allowing conventional subsea drilling up to 5,000 ft (1,520 m) using a subsea BOP and marine drilling riser.

However, the Bully rig is a customized version of the standard PRD 12,000 design, Fig. 1. The company’s in-house project name for the Bully rig was PRD 12,000 MPT, which stands for Pressurized Riser Drilling 12,000 (ft water depth) Multi-Purpose Tower. Through the company’s enhancements, the Bully’s conventional subsea drilling capability, using a subsea BOP and marine drilling riser, has been extended to 7,500 ft (2,290 m). The vessel will feature an ice-class hull, allowing for safe and efficient operation in arctic conditions. In addition, the following improvements have been added to the drillship:

Fig. 1. GustoMSC’s PRD 12,000 MPT design evolves into the “Bully” rig.

• Multi-Purpose Tower, designed by Huisman, 2,207 klb (1,000 metric tons)
• Utility hook floor 46 ft above waterline
• Static hook load to 2,400 klbs (1,088 mt)
• Riser tension load 2,000 klbs ( 908 mt)
• Setback 2,100 klbs (957 mt).

Through the use of these innovations, the design calls for less crew and fuel, allowing for competitive day rates while offering safer operations. The new drillship will have a significantly reduced environmental impact due to lower emissions through reduced fuel consumption, high-efficiency/low-emission engines and lower steel use for construction. The Bully rig’s technical specifications include: 616-ft (188-m) length, efficient 12-knot transit speed, 12,000-ft (3,660-m) water depth capability and a drilling depth rating to 40,000 ft (12,190 m). Its emission performance will exceed US EPA Tier II air emissions standards.

Dr. Matthias Bichsel, Shell E&P executive vice president, Development & Technology, said: “In meeting the energy challenge, Shell has a significant requirement for drillships in the short to medium term to enable us to undertake our deepwater and potential arctic drilling programs. This concept will lead to our drillship requirements being met at lower cost and with improved environmental performance. This, coupled with the ability to rapidly deploy the Bully rig to Shell deepwater projects between areas like the Gulf of Mexico, Nigeria, Brazil, the Far East and NW Europe, brings tremendous advantages for managing our drilling prospects and their sequencing.”

In addition, Hyundai Heavy Industries of Korea has recently signed a contract with Houston-based GlobalSantaFe for the turnkey supply of the GustoMSC P10,000 Next Generation drillship, Fig. 2. This design was the result of improvements made to the P10,000 that was deployed seven years ago. Major enhancements to the previous generation design include:

Fig. 2. GustoMSC’s P10,000 Next Generation drillship.

• Advanced dynamic positioning capabilities
• Triple activity load paths
• Derrick rated for 4 million lb
• Dual liquid-storage systems
• Larger accommodation space.