簡介：談到海洋工程項目，大都認為理念新穎、經驗充分，并能從新的角度看出來相似性，才可以取得成功。新型海洋設備技術的目的是降低投產準備時間，實現這一目標，必須進行技術創新。
New offshore construction techniques are helping to decrease the time it takes to get production systems up and running so operators can shorten the time it takes to get to first oil. Experience and the ability to innovate are critical to achieving that goal.
The ongoing pursuit of a better, more economical, and more efficient way to design, build, or install production systems has been a driver for innovation. As it gets tougher and more expensive to get hydrocarbons from offshore fields into production, J. Ray McDermott is finding new and different ways to design projects that meet customers’ unique needs.
According to Bill Soester, vice president of global engineering, finding answers is one of the company’s primary goals. “Our specialty is providing innovative solutions to help our customers.”
Finding workable solutions is particularly important for companies that perform EPCI (engineer, procure, construct, and install) projects because they are responsible for making sure every step of the process is achieved according to the project objectives. Early planning is critical to ensuring innovative, cost-effective engineering designs that can be constructed and installed successfully.
Floatover innovation
Solutions for transporting and installing integrated topsides have changed in recent years as the structures themselves have changed.
Alp Kocaman, senior consultant and naval architect at J. Ray explained, “The weight of decks has increased significantly, from about 3,000 tons to 20,000 tons. They’re too big to safely lift in one piece, and building them in several pieces is not efficient or cost-effective.”
For these reasons, floatover installation is increasingly the method of choice. The method is not entirely new. In fact, J. Ray performed floatover installations as early as the 1990s. But the game has changed.
“Not only are we dealing with these huge platforms, but they have moved from shallow, protected waters, to open waters 100 plus miles from shore, with five- to six-foot waves to contend with,” Kocaman said. The result is that innovation, renovation, and resourcefulness are required to perform complicated installations that can be carried out without incident.
Innovation at work
Recently, a worldwide team of J. Ray engineers tackled the challenge of making the Intermac 650 (I-650) transport and launch barge capable of transporting and installing the 19,000-ton topsides of PTT Exploration and Production Co.’s Arthit central facilities platform in the Gulf of Thailand.
“Built in 1982 to transport and launch jackets in the Gulf of Mexico weighing up to 40,000 tons in increasing water depths, I-650 was the largest launch barge in the world until 1987, when it became the second largest,” Kocaman explained. “It launched numerous deepwater jackets and compliant towers weighing up to 28,000 tons over the years.”
J. Ray’s scope of work on the Arthit project included construction, loadout, transportation, and installation. Because the jacket and deck were designed in a manner that made I-650 too wide for the job, J. Ray engineers proposed modifying the width of the barge, deciding on a unique configuration that reduced the bow section beam for approximately half of I-650’s length. An innovative rapid-ballast system was built into the barge as a permanent feature, rather than using a traditional setup of external pumps. The team designed a free-flooding system with large remotely controlled valves to obtain the required barge ballasting rate of about 10 ft/hr (3 m/hr) for deck-to-jacket floatover. This made I-650 one of a few vessels that use a gravity-feed ballast system and one of the fastest ballast systems around.
“We conceived the deck support frame as a loadout/transportation grillage that would align with I-650’s longitudinal bulkheads and be adaptable for future topsides floatovers of differing leg spacing,” Kocaman said.
In late 2007 and early 2008, I-650 successfully completed the task it was modified for, despite the additional challenge of the work occurring during the peak of Thailand’s northeast monsoon season, the worst season of the year. “Based on this experience, I-650 was further modified to improve operational efficiency for a project on the Su Tu Vang field offshore Vietnam,” Kocaman said.
Su Tu Vang is the biggest oil field to come onstream offshore Vietnam in the past five years and is expected to have a life span of about 20 years. Production from Su Tu Vang is about 60,000 b/d.
J. Ray performed floatover operations with the I-650 on the Su Tu Vang central processing platform jacket and topsides in late 2008. The layout was improved to optimize the use of space on the barge’s deck, coiled polyrope mats were added to prevent paint damage to the jacket legs, and a new tank gauging system and display were installed in control rooms. Another innovation was an improved 10- point mooring system.
As a result, I-650’s second floatover operation was “picture perfect,” Kocaman said. And it will improve with its third floatover, which will be for the Platong II central processing platform EPCI project, also in the Gulf of Thailand. This floatover installation will benefit from lessons learned at both Arthit and Su Tu Vang in meeting its own unique needs and weather conditions.
More opportunities
The floatover concept is evolving into applications beyond conventional facilities. Decks for tension leg platforms and semisubmersibles are becoming so large they are impractical to lift and have to be built in modules. This development also means more time has to be spent integrating between modules, which delays production startup.
Floatover capabilities being developed for J. Ray’s Altamira, Mexico, deepwater facility are one way to solve this problem.
“The beauty is that topsides of any size and configuration can be fabricated in a single piece in the yard and then integrated with the hull at the quayside,” said Mark Manfre, strategic planning manager.
“There’s a safe harbor for the hull, no ‘golden welds,’ continuous cable and piping runs, and commissioning on the ground.” Furthermore, Manfre said, performing the project in these steps can reduce construction and schedule risks.
Finding new solutions that mitigate risk is critical for the industry. As construction requirements and needs change, companies will have to rise to the challenge. Innovation will continue to be the cornerstone for offshore construction operations, and the ability to visualize beyond the familiar will be the determining element for future success.
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