Objectif From 1978 to 1984, the project group made up of HDW, LGA, Zueblin and Salzgitter AG developed two production systems for use in deep -water areas which are particularly suited to produce natural gas from offshore sites which have to be termed marginal. The support structures for the necessary process facilities comprise either a tension leg platform (TLP) or a concrete casting situated on the sea-bed.The aim of this project is to take the fundamental components of these two research and development projects as a basis on which to draw up a new concept. The idea behind this new project is to reduce investment costs to such a degree that, even in the face of decreasing prices for energy, it will be possible to produce oil and gas from marginal offshore fields economically. One particular advantage of the project described here is that the system can also be used in areas where ice can be expected.The area chosen for installation is the sea off the Norwegian coast to the north of the 62nd degree of latitude. The facility is designed merely to accommodate the equipment required to process the oil and gas. Drilling facilities will not be installed.It is assumed that the underwater field has already been developed and that the processing facility can be connected up to an existing piping system. The quality characteristics of the auxiliary and ancillary systems needed for the self-sufficient running of the plant have been specified.Due to the depressed market situation processing facilities for methane liquefaction are not considered. It is, however, planned to re-inject this constituent with associated gas to stimulate oil production. A liquefaction plant could be considered in a separate concrete casing if demand should require it.In order to achieve the largest degree of flexibility for installation of the processing equipment, it is considered to accommodate the facility in one integrated room.When placing the intermediate store in the tensioned concrete casing, special significance is placed on the ballast system, for it would have to compensate variations in buoyancy arising when filling and emptying the intermediate store. In such a case, the hydrodynamic characteristics of the overall structure should alter as little as possible.In contrast to the static requirements which require resistance to high pressure, the production procedure calls for easy-to-assemble elements, i. e. with flat surfaces. A compromise has been found between both requirements.The following most important characteristic values were determined:- effective cubic capacity- buoyancy volume- intermediate storage volume- ballast space volume- immersion depth in a floating modeThe purpose of the technical development under study is to design a production system for small deposits in deep-sea areas. In this connection, priority is given to keeping the investment and system costs as low as possible, so as to make the "marginal" fields in the northern part of the North Sea accessible to the European consumer, also at the present level of energy prices. The main items of the project:- Development of a semisubmerged tensioned concrete casing, which serves simultaneously as a buoyancy body, a production casing and a storage casing as well as the development of the foundation components (gravity foundation, piled foundation) suited to the particular buoyancy conditions and the various conditions on and in the sea-bed.- Construction of a tensioning system to anchor the concrete casing, to the foundation body and with regard to particular buoyancy conditions.- Adaptation of the process plant with regard to the determined casing to the foundation body withregard to particular buoyancy conditions.- Design of an integrated intermediate store for different products for intermittent tanker transport.- Development of a system for transferring the separated hydrocarbons from the submerged casing to the tanker.- Adaptation of the developed riser technique to the submerged production casing.- Modification of the overall system for application in arctic offshore areas (behaviour in driftice, pack ice, etc. ). Determination of the capital investment, estimation of the operating costs and final considerations of economic efficiency. - Performance of model tests. Programme(s) ENG-HYDROCARB 1C - Programme (EEC) of Community projects in the hydrocarbons sector, 1973-1985 Thème(s) 1.9 - PRODUCTION SYSTEMS Appel à propositions Data not available Régime de financement DEM - Demonstration contracts Coordinateur PREUSSAG AG (EX SALZGITTER AG) Contribution de l’UE Aucune donnée Adresse ABTEILUNG FORSCHUNG ENTWICKLUNG POSTFACH 15 06 27 1000 Berlin Allemagne Voir sur la carte Coût total Aucune donnée
