GB1317986A - Marine structures for storing and discharging liquid hydrocarbons - Google Patents

Abstract

1317986 Offshore structures COMPAGNIE INDUSTRIELLE DE TRAVAUX COMPAGNIE FRANCAISE DES PETROLES and INSTITUT FRANCAIS DU PETROLE DES CARBURANTS ET LUBRIFIANTS 24 July 1970 [30 July 1969] 36031/70 Heading E1H A caisson for storing a liquid hydrocarbon rests on the sea bed, extends above the surface 15 and comprises a reservoir 1 and a well 2 interconnected by conduits 10, 11. Initially a valve 17 is opened to flood the reservoir while valves 12 and 13 are closed. The hydrocarbon 18 then enters the reservoir and the well through a pipe 3 and the valve 13 while water 19 is expelled through the valve 17, which is closed when the hydrocarbon-water interface reaches the associated conduit 14. The hydrocarbon is discharged by a pump 5 through a two-way valve 7 and a conduit 9, the valves 12, 13 being open and the valve 17 closed. When the free-surface of the hydrocarbon reaches the conduit 11 the valve 12 is shut and sea, or fresh, water enters the reservoir through a conduit 16 so that the hydrocarbon continues to flow through the conduit 11 into the well. After the hydrocarbon has been fully discharged the valve 12 is re-opened to allow the pump to remove the now contaminated water through a conduit 8 while a fresh quantity of hydrocarbon enters through the pipe 3. A space 20 may be provided between the reservoir and an outer wall of the caisson to minimize the risk of leakage of the hydrocarbon into the ambient water. Said space may be filled with water, sand or a sand and water mixture, and accommodates the well 2. In another embodiment, Fig. 6, separate wells 2a, 2b and pumps 5a, 5b are provided for the hydrocarbon and the water. The reservoir may have a floating roof (not shown).