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The Atlantis, a deepwater oating production semisubmersible, works in 7,000 feet of water in the Gulf of Mexico. January 2012 www.sname.org/sname/mt Oshore energy production, from the earliest days in the indus- try to the advanced oating production units (FPU) in use today, can trace many of its roots to the early Gulf of Mexico. e Gulf Coast has played a unique role in the history and commerce of the United States. In the 1700s, before the beginning of the nation, the rst explorers, settlers, and traders traveled by water along the coast and up the Mississippi River to outposts, forts, and vil- lages. In the 1800s, the Gulf Coast region evolved as towns developed, served by natural ports. By the late 1800s, the American energy indus- try (the ?oil patch?) had established itself in the Northeast, Texas and Louisiana, and the West. Explorers rst searched for oil in the swamps and shal- lows of the Louisiana coast and eventually moved oshore to the deepest areas of the Gulf of Mexico. Today this region is the most prolic supplier of oil and gas in the country. e means and equipment for producing the oil and gas have varied, but most often the solutions employed an above-water work plat- form connected to oil well equipment on the seabed. Drilling and production platforms evolved in various stages as illustrated in Figure 1. As the energy industry extended oshore, demand for platforms increased rap- idly and shipyards and fabrication facilities were set up to serve the demand. Many xed-steel platforms, jack- up drilling units, and oating production platforms were designed and built along the Gulf Coast in the 1960s and ?70s. e water depth records for xed structures reached 1,700 ft. in 1984. As these depths were exceeded, the indus- try switched to oating platforms, known today as oaters. Semisubmersibles, TLPs, and spars Barge-shaped production vessels were rst employed in the very shallow calm water areas, and later adapted for regions beyond 100 ft. (30 m) water depth. e main hull types of FPUs that evolved were semisubmersible, tension leg plat- form (TLP), ship-shaped oating production storage and ooad vessel (FPSO), and spar. Each type was intended to provide a particular advantage. Semisubmersibles were low-motion oaters, with generous payload carrying capa- bilities; TLPs oered minimal heave motions and the ability to bring the production trees to the surface; FPSOs provided on-board crude oil storage and maximum payload carrying ability; and spars provided the ability to drill from the plat- form. As exploration extended to deeper waters, the benets and limitations of each concept became more evident, as shown in Table 1, and designers worked hard to overcome the limitations. The semisubmersible is truly an American-bred concept. Its roots can be found in the U.S. government- funded Project Mohole, which was undertaken by U.S. engineers. Mohole was designed to work in harsh envi- ronments o the coast of Hawaii. While this concept was not built, the idea was soon adopted for drilling platforms by U.S. drillers and oil companies including Shell Oil, Blue Water Drilling, Kerr-McGee, ODECO, SEDCO, and others. e semisubmersible concept paved the way for drillers The evolution of oating production units and what?s ahead for the industry BY MICH þÿ aAEL PRþÿ aAUþÿ gGHþÿ tT þÿ aAND þÿ DDERREN þÿ LLIU32_37_Praughtfeature_SNAME_Jan12_P3.indd 3312/22/11 3:39 PM