Abstract
As oil and gas production has moved into deeper water, and with the common requirement for platform drilling and/or frequent well intervention, new solutions have been developed to support rigid risers and surface trees. The four types of dry completion unit employed to date – jackets, compliant towers, TLPs and spars - are described and compared, along with their advantages and current limits of applicability. A database of deepwater production platforms is included.
Platform optimisation cannot be performed in isolation from riser considerations, as the requirements of the risers are intimately related to the operating characteristics of the production facility. This interrelationship, and resulting trends in both platform concepts and production riser configuration, is explored. A key issue is the tendency for the risers to displace vertically relative to the facility, which becomes very significant for softly-moored hulls in ultra-deepwater. This displacement may be accommodated by modifying the riser shape, make-up and method of support.
