A floating storage unit designed specifically for the severest environmental conditions

Abstract

This paper was prepared for the SPE-European Spring Meeting 1974 of the Society of Petroleum Engineers of AIME, held in Amsterdam, the Netherlands, May 29–30, 1974. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Netherland Section of the Society of Petroleum Engineers, P. O. Box 228, The Hague, the Netherlands. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract A description is given of an oil storage facility comprising a combination of a number of vertical cylinders, forming a complete unit. Anchored to the bottom of the sea yet movable to another location if required, the floating unit has been designated a storage spar. The paper deals with the behaviour of the unit in certain sea states and with those parameters which effect motions due to wind, parameters which effect motions due to wind, waves and current. The basic philosophy of the design is discussed. Some attention is also given to the structural aspects of anchoring, tanker mooring and oil handling. The paper also goes into some detail on the fabrication of the unit, its upending after launching, and its final installation at site. Introduction A glance at the map of the North Sea shows the presence of a number of highly interesting oil and gas discoveries many of which are scheduled to come into production very soon. The discovery of these new sources of hydrocarbons, and their location, sparked off a great deal of research and development activity leading eventually to the designing of equipment able to stand up to the severe and hostile environmental conditions peculiar to this northernmost portion of the North Sea. Because of the excessive water depths involved, plus the severe weather conditions, most structures going into this area have to be large and have to be heavy. And since we are only just on the brink of development, activity is bound to increase considerably into the future. This means that water up to 200 meters deep will have to be contended with.