US3605774A

US3605774A - Maritime apparatus utilizable as a hydrocarbon reservoir

Info

Publication number: US3605774A
Application number: US56289A
Authority: US
Inventors: Pierre Launay; Tran Dinh Phat
Original assignee: IFP Energies Nouvelles IFPEN; Compagnie Francaise des Petroles SA; INDUSTRIELLE DE TRAVAUX Cie
Current assignee: Total Compagnie Francaise des Petroles SA; IFP Energies Nouvelles IFPEN; INDUSTRIELLE DE TRAVAUX Cie
Priority date: 1969-07-30
Filing date: 1970-07-20
Publication date: 1971-09-20
Anticipated expiration: 1988-09-20

Abstract

A marine installation for storing hydrocarbon liquids has a reservoir containing the hydrocarbon liquid and water beneath the hydrocarbon liquid. As the hydrocarbon liquid enters the reservoir water is removed. When the hydrocarbon liquid is removed water is added to maintain sufficient ballast in the installation to keep the installation immersed and in place.

Description

Sept. 20, 19'" p, LAUNAY E'I'AL 3,605,774

MARITIME APPARATUS UTILIZABLE AS A HYDROCARBON RESERVOIR Filed July 20, 1970 3 Shuts-Shoot 1 FIG. 2

FIG. 4

Sept. 20, 1971 p, LAUNAY EIAL 3,605,774

MARITIME APPARATUS UTILIZABLE AS A HYDROCARBON RESERVOIR Filed July 20. 1970 3 Sheets-Sheet 2 FIG. 5

FIG. 4

FIG.- 3

United States Patent O1 hoe U.S. Cl. 137-1 12 Claims ABSTRACT OF THE DISCLOSURE A marine installation for storing hydrocarbon liquids has a reservoir containing the hydrocarbon liquid and water beneath the hydrocarbon liquid. As the hydrocarbon liquid enters the reservoir water is removed. When the hydrocarbon liquid is removed water is added to maintain sufiicient ballast in the installation to keep the installation immersed and in place.

SUMMARY OF THE INVENTION The present invention has for its object to provide maritime apparatus utilizable as a hydrocarbon liquid reservoir.

A further object of the present invention is to utilize structures of reinforced concrete, of prestressed concrete or of metal to provide portable apparatus to provide protection for liquid hydrocarbons; to assist in the landing of hydrocarbon liquids from super tankers; to store and to transport hydrocarbon liquids under such conditions that contact between the hydrocarbon liquids and the outside sea is impossible.

Maritime installations in accordance with the present invention usable as hydrocarbon liquid reservoirs are characterized by the fact that they comprise at least one caisson having at least one reservoir for the storage of hydrocarbon liquids, at least one feed pipe for the hydrocarbon liquids discharging into the upper part of the reservoir, at least one duct for water opening into the lower part of the reservoir, at least one pump well communicating with the reservoir through at least one diversion conduit controlled by a valve, this conduit being located at a height at least equal to that of the level of the hydrocarbon liquid forming a ballast sufiicient to assure the stability of the installation and a pump at the bottom of each of the pump wells connected to a discharge duct.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with respect to the accompanying drawings illustrating preferred embodiments thereof, in which drawings like reference characters indicate like parts.

In the accompanying drawings, FIG. 1 is a vertical cross-section of a preferred embodiment of a marine installation in accordance with the present invention;

FIG. 2 is a similar view to that of FIG. 1 showing the first filling of the installation;

FIG. 3 shows the embodiment of FIG. 1 at the end of the first filling thereof;

FIG. 4 shows the embodiment of FIG. 1 when it is first emptied;

FIG. 5 shows the embodiment of FIG. 1 at the time of its second filling, and for subsequent fillings; and

FIG. 6 shows another embodiment of the present invention with separate pump wells for water and for the hydrocarbon liquids.

3,605,774 Patented Sept. 20, 1971 DESCRIPTION OF PREFERRED EMBODIMENTS The installation of FIGS. 1-5 has a vertical reservoir 1 and pumping wells 2. In vertical reservoir 1 is a feed duct 3 for hydrocarbon liquids ending in a diffuser 4. A floating roof can be used, in known way, on reservoir 1. This roof would float on the hydrocarbon liquid in the reservoir.

A submerged pump 5 is located at the base of the pump well 2. This pump is in communication with the evacuation pipe 6 controlled by a valve 7 to place pipe 6 either in communication with conduit 8 for removal of water or with a conduit 9 for evacuation of the hydrocarbon liquid. The evacuation of the hydrocarbon liquid can be to a tanker, to a reservoir, or to a similar marine installation.

Two

diversion conduits

10 and 11 are located between reservoir 1 and the pump well 2, the first being located adjacent to the bottom of the reservoir and the second between the bottom and the top of the reservoir.

Valves

12 and 13 are placed in the

conduits

10 and 11, respectively, to close or open these conduits.

A conduit 14 is located at the bottom of the reservoir to place the same in communication with the outside water. The outside water level is represented schematically at 15.

A duct 16 for the circulation of water opens at the bottom of the reservoir and can be placed in communication with a closed enclosure (not shown) either of pure water or of water already polluted by a hydrocarbon.

Valve 17 closes conduit 14.

In the embodiment of FIG. 6, the caisson has two

wells

2a and 2b in place of well 2. Well 2a communicates with reservoir 1 at a level intermediate between the bottom and the top of the reservoir through conduit 11 closed by valve 13. Submerged pump 5a at the bottom of pump well 2a is in communication with pipe 6a opening through valve 7a to place pipe 6a in communication with conduit 9 for removal of the hydrocarbon liquid. Well 2b com municates with reservoir 1 at the base of the reservoir through conduit 10 closed by valve 12. Submerged pump 5b, located at the bottom of pump well 2b, is in communication with pipe 6b opening through valve 7b to place pipe 6b in communication with conduit 8 for removal of Water.

The installation described above with respect to FIGS. 1-5 is used in the following way.

In the initial stages, the level of the water Within reservoir 1 is the level 15 of the exterior water or of the sea. To make the first filling, valve 17 is opened and

valves

12 and 13 remain closed. Reservoir 1 is then filled with water from the sea having a level between that of the base of the reservoir and of the surrounding sea. To proceed with the filling, hydrocarbon liquid is introduced through conduit 3 and diffuser 4 which is located in the middle of the floating roof (not shown in the drawings) until the interface between the water and the hydrocarbon liquid reaches the upper level of conduit 14 and valve 17 is then closed. The filling of the reservoir can then be completed through conduit 3, all the valves being closed.

FIG. 2 shows the filling operation of the reservoir by means of a hydrocarbon liquid, the hydrocarbon liquid being represented at 18 and the Water being represented at 19. At the end of the filling stage, valve 17 being closed, reservoir 1 is full of hydrocarbon liquid with a layer of water 19 in the lower part of the reservoir which layer is more or less polluted with hydrocarbon liquid because of the turbulence due to the pumping of the hydrocarbon liquid.

For removal of the hydrocarbon liquid, valve 17 is maintained closed and so is valve 12 while upper valve 13 is open. Submerged pump 5 is then actuated for removal of the hydrocarbon liquid to a pumping station or to a tanker or to other marine installations until the upper level of the hydrocarbon liquid approaches the level of conduit 11 and valve 13. At this time, sea water is introduced into reservoir 1 through conduit 16. This introduced sea water raises the level of the hydrocarbon liquid which passes through conduit 11 and through valve 13 which is open. This hydrocarbon liquid is taken up by pump 5, as above.

When reservoir 1 is completely empty of hydrocarbon liquid, the second filling can proceed. Valve 17 is always maintained closed as well as the two

valves

12 and 13. Reservoir 1 is full of sea water up to the level of conduit 11. Lower valve 12 is then opened and filling with hydrocarbon begins through conduit 3 while simultaneously operating submerged pump 5 in such a way so as to remove the polluted sea water from reservoir 1 to reservoirs (not shown) utilizing duct 8 for this purpose.

Filling of reservoir 1 is continued and the interface of the hydrocarbon liquid with the sea water is lowered toward the base of reservoir 1. At suitable time, valve 12 is closed, valve 13 is opened and the installation is in the original condition described above at which evacuation of the hydrocarbon can take place through submerged pump 5 and duct 9.

In the embodiment of FIG. 6, the operation is quite comparable. However, in this case, instead of directing water and hydrocarbon liquid alternately into well 2, the two liquids are evacuated by separate pumps with separate valves 7 discharging into ducts 8 and 9, respectively, control the

valves

12 and 13 then introducing, respectively, the hydrocarbon liquid into well 2a and water into well 2b,

pump

5a and 5b being utilized respectively for pumping the hydrocarbon liquid to duct 9 and the water to duct 8.

It will be noted from the above that, other than during the first filling, the reservoir is never in communication with sea water from outside the reservoir. The operations of admission and removal of polluted sea water always take place in a closed circuit from reservoir 1 to another reservoir or to a tanker or to another marine installation.

A marine installation in accordance with the present invention is particularly economical to build because of the fact that its ballast, necessary to assure its stability during immersion in the presence of exterior forces such as currents, waves, storms, and the like, is obtained primarily by water in contact on an interface with the hydrocarbon. The level of the water varies as a function of the volume of the hydrocarbon, always maintaining in the reservoir a minimum volume of liquid at least equal to that required to maintain reservoir 1 Stable under all conditions of use.

The present invention has numerous advantages.

Firstly, the installation protects the hydrocarbon liquid content and may be utilized for storing the hydrocarbon liquid. The arrangement of the pumps and valves prevents any pollution of the outside sea water.

Further, earth backings usually required with known surface reservoirs are completely eliminated.

Dangers of explosion or of fire are practically eliminated since the greatest part of the stored hydrocarbon liquid is below the level of the sea, sheltered in these very strong installations and thus completely protected.

Expansion of the installations can take place progressively as needed and a new landing area includes its own storage for petroleum products.

When intended for use in the open sea, the caissons and reservoirs can be prefabricated in a port, towed to the proper location and immersed with their equipment completely in place within requiring work at sea in an exposed site.

The exterior of the caisson can be made with a double wall defining a space 20 which can be filled with Water thus assuring a fluid seal between the reservoir 1 and the sea. If losses occur between reservoir 1 and the space 20, the hydrocarbon comes to the surface of the water in space 20 and can be removed. Space 20 may also be filled with a solid material in dispersed state with a density at least equal to water, for example, sand. Another suitable filling for space 20 is a mixture of water and sand.

The exterior wall of the double wall of the caisson can also be made fluid tight thus forming a retention reservoir in space 20 and providing maximum security against contamination of the sea.

The shape of the caisson, reservoir 1 and the other components of the structure is easily adapted to utilize known apparatus from terrestrial reservoirs particularly in the case of the floating roof.

The invention is not limited to the embodiments described above. Thus, conduit 14 and its valve 17 are primarily used to facilitate the first immersion of the caisson, they are therefore not absolutely indispensable and can be removed if other means are used to fill the caisson with water when it is put in place.

Further, conduit 10 and its valve 12 are not absolutely indispensable. If they are not used, conduit 16 can be used to introduce water into reservoir 1 during removal of the hydrocarbon liquid and for removal of water during filling with the hydrocarbon liquid. Finally, while the utilization of sea water for partial filling of the reservoir is practical and economical, it is obvious that fresh water could be used as well.

What is claimed is:

1. A partially submerged marine installation for storage of hydrocarbon liquids comprising at least one caisson, at least one reservoir for storing of hydrocarbon liquids in said caisson, at least one feed conduit for the hydrocarbon liquids opening into the upper part of said reservoir, at least one Water conduit opening into the lower part of said reservoir, at least one pump well communicating with said reservoir through at least one diversion conduit, a valve in said diversion conduit, said conduit being located at a height at least equal to the level of the quantity of hydrocarbon required as ballast for stability of the installation, a pump at the bottom of said pump well and an evacuation pipe connected to said pump.

2. Marine installation as described in claim 1, including at least one conduit opening into said reservoir at the bottom of said caisson opening into the sea and a valve in said conduit.

3. Marine installation as described in claim 1, said evacuation pipe including at least one at distribution valve, a first conduit connected to said valve for the evacuation of hydrocarbon liquid and a second conduit connected to said valve for evacuation of water.

4. Marine installation as described in claim 1, said caisson having spaced double outer walls, and material filling the space bet-ween said walls having a density at least equal to that of water.

5. Marine installation as described in claim 4, the exterior wall of said double walls being fluid-tight forming a retention reservoir with the other of said outer walls.

6. Marine installation as described in claim 4, the material filling the space between said double walls being a dispersed solid.

7. Marine installation as described in claim 1, said caisson including at least one pump well for receiving water and at least one pump well for receiving hydrocarbon liquid, separate pumps in said wells, a conduit connecting said well for water to the lower part of said reservoir and a valve in said conduit.

8. Marine installation as described in claim 3, including a conduit between said pump well and the bottom of said reservoir and the valve closing said conduit.

9. Method of storing hydrocarbon liquids in an immersed marine installation with suificient liquid therein for ballast for the stability of the installation, the steps of first filling a reservoir in the installation by closing communication valves from the reservoir to pump wells therein, filling the reservoir with sea water through a feed conduit to a level for the desired immersion, closing the water feed conduit, then introducing the hydrocarbon liquid through a hydrocarbon liquid feed pipe to the upper end of the reservoir and simultaneously removing a corresponding volume of water whereby the interface between the water and the hydrocarbon liquid approaches the bottom of the reservoir, thereafter removing the hydrocarbon liquid from the reservoir by opening the valve in a first conduit from the reservoir to the pump well, actuating the pump to remove the hydrocarbon liquid flowing by gravity into the pump well until the level of the hydrocarbon liquid reaches the level of said first conduit, introducing water into the reservoir through a water conduit until the interface between the water and the hydrocarbon liquid reaches the level of said first conduit then deactivating the pump after emptying the pump well and thereafter refilling the reservoir with a hydrocarbon liquid by closing said first conduit to the pump well and simultaneously removing a volume of water corresponding to the added hydrocarbon liquid.

10. Method as described in claim 9, the simultaneous evacuation of water and filling with the hydrocarbon liquid being carried out by opening a valve in a second conduit connecting the base of the pump well to the base 6 of the reservoir through which the water flows by gravity and then actuating the pump for removal of the water.

11. Method as described in claim 9, the evacuation of water simultaneous with filling of the reservoir by the hydrocarbon liquid being carried out by opening a valve in a conduit connecting the base of a pump well for water and the base of the reservoir and actuating a pump in the water pump well for removing the water.

12. Method as described in claim 9, including the step of storing the water withdrawn from the pump wells and thereafter reintroducing the stored water into the reservoir during removal of the stored hydrocarbon liquid.

References Cited UNITED STATES PATENTS 3,488,969 1/1970 Lacy 61.5X

ALAN COHAN, Primary Examiner US. Cl. X.R.