57- www. energy- future. com 5.2- Technology: pushing boundaries engineering and operations at Petrofac, an oil field services company. " In addition, there are several thousand sub- contracts on a $ 500 million project." The oil or services company running the project must ensure that all those thousands of bits of kit are compatible with each other, meet the requisite quality standards and that they arrive on time and are - to use a bit of industry jargon - fit for purpose. The late arrival of equipment and materials, or a de-sign flaw, can lead to costly delays and im-pair project economics. Real estate on a platform's deck is ex-pensive, so the engineers are aiming to de-sign platforms that are as small and light as possible, without compromising stability and safety. That means improving layout, min-iaturising equipment, removing redundant equipment or using lightweight construc-tion materials. Sophisticated software pro-grammes have proved invaluable, enabling engineers to create minutely detailed 3- D computer models of a facility before a well has been drilled or a pipe ordered. As well as the on- board facilities - those that separate out the gas and liquids from the production stream, store produced oil and accommodate the crew, for example - scientists are continually looking for ways to reduce the weight of the subsea equipment, from the mooring chains and the risers that carry the oil and gas to the surface to drilling, production and processing equipment. Less weight hanging from the platform = smaller platform = more profitable development. Constructing giants The platform designers' vision starts be-coming reality at fabrication yards, where the structures are assembled by hundreds of welders, fitters, crane operators, paint-ers and riggers. At the height of the oil boom that peaked in mid- 2008, more than 80 rig-building yards - which are usually on wa-terfronts - existed around the world ena-bling the growth of the offshore industry. The yards are immense. The world's largest, a South Korean facility owned by Hyundai, covers 7.2 million square metres. With huge mobile cranes that can lift as much as 1,500 tonnes, giant pieces of equip-ment used to roll flat plate into tubular sec-tions and immense buildings with overhead cranes for working indoors in bad weather, the largest fabrication facilities are as im-pressive as the superstructures they build. And managing them requires broad- rang-ing engineering and technical skills - and teamwork. " For major structures," says Ray 18922009 Gilbert H. Grosvenor Collection

58- www. world- petroleum. org 5.2- Technology: pushing boundaries Serpas, an engineering manager at US plat-form contractor J Ray McDermott, " the engi-neer needs to work closely with the fabrica-tor and installer, because the loading during the fabrication and installation phases can control a large portion of the design." Not all platforms are new. Old oil tank-ers are sometimes converted into floating, production, storage and offloading vessels. Or a rig that was designed for one field can be adapted for use at another. Reusing old equipment isn't easy: precision measuring using lasers is necessary to ensure that new bits of kit will fit properly, for instance. But it makes obvious financial sense. For one thing, it's usually cheaper. And, for another, it's generally much quicker than building something from scratch. Speed is important because reducing the time it takes to get the oil flowing has a significant bearing on the economics. Platforms on the move While transportation and installation usu-ally take less time than other aspects of a platform project, these phases are none-theless risky and costly. The original de-sign must take account of the tools that will be needed for the installation phase - in some cases, massive, ship- mounted der-rick cranes that must be booked years in advance; the world's largest semi- submersi-ble crane vessel, owned by marine contrac-tor Heerema, has a lifting capacity of 14,200 tonnes. Inadequate early planning can lead to costly rework, equipment availabil-ity problems and schedule delays, says Kirt Raymond, a general manager at J Ray. Often a platform, or part of one, will have to be shipped a considerable dis-tance, from fabrication yard to field, add-ing another layer of logistical complication. Thunder Horse's 60,000 tonne hull was constructed in South Korea. Anything but straightforward Installation methods vary, depending on the type of structure and its location. Take a fixed platform, for example: once the main structural component - the sub-structure, or jacket, arrives at its destina-tion, it is up- ended from a horizontal to ver-tical position and lowered to the bottom of the ocean. Then it is levelled and piles are driven through the legs of the jacket into the seafloor. Next, the topsides, or deck, are lifted into place and set on top of the piling. The pieces are connected and other opera-tions required to complete the structure are conducted. Finally, the drilling rig and other equipment modules are put in place. If it sounds straightforward, it's anything but. The sheer size and weight of these mas-sive structures add significantly to the diffi-culties involved in executing each of these steps, making platform design, construction and installation one of the world's most in-credible feats of engineering. ?? 19462009