Vortex Induced Motion is a well-known but complicated phenomenon for Spar hulls and model testing is
still the norm to determine the platform’s VIM response. Towing tests are widely accepted for VIM model
tests; however this test method only simulates a uniform current profle with depth. In the actual ocean
environment, only sheared currents are present so the tow test method over-predicts the loading on the
cylinder from current, particularly in the deeper portions of the hull. To achieve more realistic test results
for VIM testing, it is desirable to use sheared currents for Classic Spar.
Y.C. (Young-Chan) Park is a Principal Naval Architect E&C – offshore engineering at Williams. Y.C. has more than 20
years of foating production system detail engineering experience in the offshore industry. He provides technical
support for hull and mooring of deepwater foating production systems.
DRY-TREE SEMI-SUBMERSIBLE PLATFORMS FOR
THE ULTRA-DEEPWATER GULF OF MEXICO
Ming-Yao Lee, Chevron
With increasing exploration success of ultra-deepwater felds in the Gulf of Mexico, there is a considerable
interest and need to look for a safe, reliable and cost-effective dry-tree option to maximize the value of
deepwater feld developments. Dry-tree semi-submersible emerges as such an option to overcome the
water depth and size limits imposed by TLP and Spar, and enables the platform to carry a large well array
and payloads in ultra-deep water. Moreover, it has the capability for quayside topsides installation and
integration. This presentation will highlight Chevron’s multi-year efforts in leading the industry to mature
two promising semi-submersible platform concepts that can accommodate long-stroke dry-tree risers and
have large drilling and production capabilities. Results of technology development and qualifcation will
be presented with emphasis on hull performance and hull/riser interfaces.
Dr. Ming-Yao Lee is an Offshore & Marine Engineering Team Manager at Chevron. Dr. Lee is currently heading a multidisciplinary team providing technical service and research development to support Chevron’s major capital projects
and operations for foating offshore facilities and marine terminals. Prior to joining Chevron in 2000, he worked
for Earl & Wright Consulting Engineers and American Bureau of Shipping. He has 30 years of practical design and
research experiences in the offshore industry.
COMPARISON OF SEMI-SUBMERSIBLE DECK ALTERNATIVES, INTEGRATED
DECK BOX AND TRUSS DECK
Tobias Kärrsten, GVA
Both stiffened plate (deck box) and tubular/beam (truss deck) construction of topside decks is used for
semi-submersible production platforms. Each design has its technical, operation, safety and fabrication
benefts and issues. These benefts and issues for each design have been compared and evaluated in this
presentation. In addition today’s fabrication and dry-transport capability to build the topside integrated
with the hull in a far-east fabrication yard.
Tobias holds a Master Degree in Mechanical Engineering at the University of Chalmers, Gothenburg Sweden. Tobias
has more than 15 year experience from analysis and design in concept, pre-feed and feed phases of foating
production, drilling and accommodation units. In addition Tobias has experience with ship yard supervision, marine
operations, mooring system installation and commissioning of offshore platforms.