On behalf of Phillips Petroleum Company E &A, Tecnomare S.p.A. has designed a steel gravity platform (TSG) for the development of the Maureen Field in the British Sector of the North Sea. The platform is now under construction. Basic features of TSG platform include drilling and production facilities, storage capacity, full top-side equipment transportation and the capability to be installed over a template of predrilled wells for early production development system. The paper deals with the reasons why this solution has been selected with reference to the main characteristics of the TSG platform. The key role of this type of platform in the development of marginal fields is pointed out. The requirement of keeping to a minimum the total investment costs is a must for such marginal fields The paper shows how the form chosen for this sub-structure has been dictated by the following considerations: the need for rapid installation at location, zero offshore hook-up, storage capacity to complement the offshore loading system and the rapid oil flow start-up. Adopted design methods to analyse the structure during construction, transportation and installation phases are presented. In particular the following items, strictly related to the TSG concept, are treated:
hydrodynamic aspects of load calculation,
soil/structure interaction,
ring stiffened large joint analysis,
positioning and installation system,
storage process system,
structural monitoring system.
The relevant main results will be discussed. The basin model test program is described and the main test results are compared with the theoretical calculations. Main operating aspects are discussed such as:
construction in dry dock and tow-out,
deck mating in sheltered deep water site,
transportation and installation.
Tecnomare has designed, on behalf of Phillips Petroleum Company E &A, a Steel Gravity platform, with integrated oil storage, to be installed in the Maureen Field, in the British Sector of the North Sea. Tecnomare1s interest in the Maureen Field development dates from Summer 1975. Since that time several proposals have been made concerning the structure to be used for the exploitation of the field. In 1977 the Operator carried out detailed studies regarding two basic development concepts, which were:
A workover and production platform installed over a subsea template with predril1ed wells.
A drilling and production platform installed on a bare sea-bed.
Both concepts were to incorporate storage facilities and a tanker mooring and offshore loading system. While the latter is a conventional field development, the former is an application of the "early production" philosophy.
A comprehensive and detailed study was undertaken, approaching many designers and fabricators and investigating all kinds of available solutions. The conclusion has been that the early production concept was practicable and that the Tecnomare Steel Gravity (TSG) platform was the most suitable to accomplish it.
