Alliance Delivers Topsides for Deepwater Perdido Spar

Wood Group

Alliance Wood Group Engineering ("Alliance"), part of international energy services company John Wood Group PLC ("Wood Group"), designed the topsides of the Perdido Development facility, which was mated with its spar recently in a record single lift. Located in the Gulf of Mexico Alaminos Canyon Block 857 in 7,817 feet of water, approximately 200 miles from Houston, Perdido will become the world's deepest offshore oil & gas drilling and production facility. It is operated by Shell on behalf of partners Chevron and BP.

Alliance provided the conceptual design, front-end engineering, detailed design, construction support and installation/commissioning support for this unique topsides deck. The 9,773 short-ton topsides and rigging -- a U.S. record for the Gulf of Mexico -- were lifted in place by Heerema Marine's Thialf. Alliance continues to provide commissioning assistance.

According to Alliance President Norb Roobaert, "The Perdido topsides design was instrumental in the project's success. The Alliance lightweight topsides design techniques were a key enabler to permit Shell to advance this project. When combined with Shell's innovative solutions to reduce the riser load, this resulted in significant weight reduction and a significant savings in time and cost, as well as producing a safer facility."

The design accommodates production from five subsea, direct vertical access separation caissons for this host facility. Alliance demonstrated its ingenuity and flexibility, engineering a fit-for-purpose design in close tandem with Shell to successfully develop this challenging world-class project.

Alliance has a history of successfully developing topsides for major offshore oil and gas fields, including lightweight deepwater topsides, shelf platform topsides, and FPSO topsides. Alliance is a major player in engineering and design of the world's biggest offshore projects: Alliance's 10 largest installed Gulf of Mexico projects are together capable of producing approximately 655,000 barrels of oil and 2 billion cubic square feet of natural gas per day -- or roughly 12% of the United States' estimated daily domestic oil production and 30% of the United States Gulf of Mexico estimated natural gas production in 2009 (source:

Two other Wood Group companies provided services for the Perdido project. Multiphase Solutions Inc. ("MSi") supplied the Transient Engineering Simulator subsea simulation package, which was integrated into the Perdido operator training simulator and deployed for operator training in April at Shell's offices in New Orleans. Deepwater Specialists Inc. ("DSI") provided start-to-finish commissioning services.