U.S. patent application number 14/868052 was filed with the patent office on 2016-01-21 for sea vessel docking station.
This patent application is currently assigned to ANADARKO PETROLEUM CORPORATION. The applicant listed for this patent is Anadarko Petroleum Corporation. Invention is credited to Charles H. King, Eric E. Maidla, Keith K. Millheim.
Application Number | 20160016647 14/868052 |
Document ID | / |
Family ID | 36649089 |
Filed Date | 2016-01-21 |
United States Patent
Application |
20160016647 |
Kind Code |
A1 |
Millheim; Keith K. ; et
al. |
January 21, 2016 |
Sea Vessel Docking Station
Abstract
A system and method in which a buoyant central docking station
captures, lifts and couples one or more other sea vessels is
disclosed, wherein a flexible, modularized production system is
quickly realized on a cost effective basis. The capabilities of a
number of older, less expensive, readily available vessels are
combined to achieve an effective FPSO substitute that allows lower
producing fields to be explored and produced in a profitable
manner. The time horizon between initiation and consummation of
field operations is reduced, and older vessels that might otherwise
be scrapped or retired are again made useful and seaworthy in a
safe and profitable exploration and production environment.
Inventors: |
Millheim; Keith K.; (The
Woodlands, TX) ; Maidla; Eric E.; (Sugar Land,
TX) ; King; Charles H.; (Austin, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Anadarko Petroleum Corporation |
The Woodlands |
TX |
US |
|
|
Assignee: |
ANADARKO PETROLEUM
CORPORATION
The Woodlands
TX
|
Family ID: |
36649089 |
Appl. No.: |
14/868052 |
Filed: |
September 28, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13787395 |
Mar 6, 2013 |
|
|
|
14868052 |
|
|
|
|
13016662 |
Jan 28, 2011 |
|
|
|
13787395 |
|
|
|
|
12346214 |
Dec 30, 2008 |
|
|
|
13016662 |
|
|
|
|
12150608 |
Apr 29, 2008 |
|
|
|
12346214 |
|
|
|
|
11285439 |
Nov 22, 2005 |
|
|
|
12150608 |
|
|
|
|
60695727 |
Jun 29, 2005 |
|
|
|
Current U.S.
Class: |
114/45 |
Current CPC
Class: |
B63B 35/44 20130101;
B63C 1/02 20130101 |
International
Class: |
B63C 1/02 20060101
B63C001/02; B63B 35/44 20060101 B63B035/44 |
Claims
1. A wet docking station for exploring and producing offshore
energy sites, the wet docking station comprising: a buoyant central
docking station; an adjustable buoyancy chamber for adjusting the
buoyancy of said buoyant central docking station; and at least one
subordinate docking station for capturing and lifting at least one
sea vessel; wherein said at least one sea vessel_is equipped with
at least one of a helicopter pad; a crew quarters; a ship control
room; an oil separating unit; a gas separating unit; a water
separating unit; a sand separating unit; a gas treatment unit; a
gas injection unit; and a power generating unit.
2. The wet docking station of claim 1, wherein said adjustable
buoyancy chamber further comprises a chamber that is externally
disposed relative to said central docking station.
3. docking station of claim 1, wherein said adjustable buoyancy
chamber further comprises a chamber that is internally disposed
relative to said central docking station.
4. The wet docking station of claim 1, wherein said adjustable
buoyancy chamber further comprises a plurality of discrete inner
chambers.
5. The wet docking station of claim 1, wherein said adjustable
buoyancy chamber further comprises at least one fluid intake port
and at least one fluid evacuation port.
6. The wet docking station of claim 1, further comprising a
coupling member used to couple said at least one sea vessel to said
central docking station.
7. The wet docking station of claim 1, further comprising a
coupling member used to couple a plurality of captured sea vessels
to one another.
8. The wet docking station of claim 7, wherein said coupling member
further comprises an intermediate deck surface.
9. The wet docking station of claim 1, wherein said at least one
sea vessel further comprises an offshore energy exploration
equipment package.
10. The wet docking station of claim 1, wherein said at least one
sea vessel further comprises an offshore energy production
equipment package.
11. A method of exploring and producing offshore energy sites using
a wet docking station, the method comprising: disposing a buoyant
central docking station in communication with an adjustable
buoyancy chamber, wherein said adjustable buoyancy chamber is used
to adjust the buoyancy of said buoyant central docking station;
disposing said buoyant central docking station in communication
with at least one subordinate docking station, wherein said at
least one subordinate docking station is used to capture and lift
at least one sea vessel; and equipping said at least one sea
vessel_with at least one of a helicopter pad; a crew quarters; a
ship control room; an oil separating unit; a gas separating unit; a
water separating unit; a sand separating unit; a gas treatment
unit; a gas injection unit; and a power generating unit.
12. The method of claim 11, further comprising disposing an
adjustable buoyancy chamber that is externally disposed relative to
said central docking station.
13. The method of claim 11, further comprising disposing an
adjustable buoyancy chamber that is internally disposed relative to
said central docking station.
14. The method of claim 11, further comprising disposing an
adjustable buoyancy chamber having a plurality of discrete inner
chambers.
15. The method of claim 11, further comprising disposing an
adjustable buoyancy chamber having at least one fluid intake port
and at least one fluid evacuation port.
16. The method of claim 11, further comprising disposing an
adjustably buoyant central docking station having a coupling member
used to couple said at least one sea vessel to said central docking
station.
17. The wet docking station of claim 11, further comprising
disposing a buoyant central docking station having a coupling
member used to couple a plurality of captured sea vessels to one
another.
18. The method of claim 17, further comprising disposing a buoyant
central docking station having an intermediate deck surface.
19. The method of claim 11, further comprising equipping said at
least one sea vessel with an offshore energy exploration equipment
package.
20. The method of claim 11, further comprising equipping said at
least one sea vessel with an offshore energy production equipment
package.
Description
STATEMENT OF RELATED CASES
[0001] The present application is a continuation of U.S.
Non-Provisional application Ser. No. 13/787,395 filed Mar. 6, 2013,
still pending, which is a continuation of U.S. Non-Provisional
application Ser. No. 13/016,662 filed Jan. 28, 2011, now abandoned,
which is a continuation of U.S. Non-Provisional application Ser.
No. 12/346,214 filed Dec. 30, 2008, now abandoned, which is a
continuation of U.S. Non-Provisional application Ser. No.
12/150,608 filed Apr. 29, 2008, now abandoned, which is a
continuation of U.S. Non-Provisional application Ser. No.
11/285,439 filed Nov. 22, 2005, now abandoned, which claims the
benefit of prior provisional application no. 60/695,727, filed Jun.
29, 2005.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to offshore oil and
gas exploration and production systems, and in a specific,
non-limiting embodiment, to a system and method of capturing,
lifting and coupling a plurality of sea vessels using a centralized
wet docking station, so that relative deck sizes are effectively
increased, and equipment packages and other facilities are
exchanged between the decks of captured vessels in a stable and
efficient manner.
BACKGROUND OF THE INVENTION
[0003] Innumerable systems and methods have been employed in
efforts to find and recover hydrocarbon reserves around the world.
At first, such efforts were limited to land operations involving
simple but effective drilling methods that satisfactorily recovered
reserves from large, productive fields. As the number of known
producing fields dwindled, however, it became necessary to search
in ever more remote locales, and to move far offshore, in the
search for new resources. Eventually, sophisticated drilling
systems and advanced signal processing techniques enabled energy
companies to search virtually anywhere in the world for recoverable
hydrocarbons.
[0004] Initially, deepwater exploration and production efforts
consisted of expensive, large scale drilling operations supported
by tanker storage and transportation systems, due primarily to the
fact that most offshore drilling sites are associated with
difficult and hazardous sea conditions, and thus large scale
operations provided the most stable and cost-effective manner in
which to search for and recover hydrocarbon reserves, A major
drawback to the large-scale paradigm, however, is that explorers
and producers have little financial incentive to work smaller
reserves, since potential financial recovery is generally offset by
the lengthy delay between exploration and production (approximately
3 to 10 years), and by the large capital investment required for
conventional platforms and related drilling, production and
transportation equipment. Moreover, complex regulatory controls and
industry-wide risk aversion have led to standardization, leaving
operators with few opportunities to significantly alter the
prevailing paradigm. As a result, offshore drilling operations have
traditionally been burdened with long delays between investment and
profit, excessive cost overruns, and slow, inflexible recovery
strategies dictated by the operational environment.
[0005] More recently, deepwater sites have been found in which much
of the danger and instability usually present in such operations
can be avoided. For example, off the coast of West Africa,
Indonesia and Brazil, potential drilling sites have been identified
where surrounding seas and weather conditions are relatively mild
and calm in comparison to other, more volatile sites such as the
Gulf of Mexico and the North Sea. These recently discovered sites
tend to have favorable producing characteristics, yield positive
exploration success rates, and admit to production using simple
extraction and transportation techniques similar to those employed
in dry land or near-shore operations.
[0006] However, since lognormal distributions of recoverable
reserves tend to be spread over a large number of small fields,
each of which yield less than would normally be required in order
to justify the expense of a conventional large-scale operation,
most such regions have to date been underexplored and underproduced
relative to their potential. Consequently, many potentially
productive smaller fields have already been discovered, but remain
undeveloped due to economic considerations.
[0007] Currently, most deep water exploration and production
operations are facilitated by means of a large, expensive floating
production and storage offtake (FPSO) vessel, which is used to
arrange and store essentially all of the facilities and equipment
packages likely to be required aboard a single ship, with lesser
vessels being employed only in support roles for purposes such as
transporting crews back and forth from shore, delivery of new or
replacement equipment packages, etc.
[0008] As seen in prior art FIG. 1, for example, an FPSO system 100
similar to those presently being employed in the field is depicted,
wherein the FPSO comprises a large deck surface (e.g., in excess of
about 20,000 square feet) capable of accommodating useful
operational structures such as a helicopter pad 101; officer, crew
and control rooms 102; a water treatment facility 103; one or more
fluid injection pumps 104; one or more oil, gas, sand and water
separators 105; a gas treatment injection facility 106; a power
generator 107; and a gas flare 108.
[0009] The FPSO has deck space for uploading additional equipment
packages from other vessels on an as-needed basis, and serves as a
central station for the entire exploration and production
operation. In one common application, the FPSO is held in place
during operations by a mooring system using a plurality of mooring
lines (not shown) that are tied off to other vessels, mooring
buoys, etc. In alternative embodiments, the FPSO is moored to a
turret, so that it essentially revolves around a fixed point; and
in a further embodiment, the FPSO is dynamically positioned, so
that it is allowed to move in response to wave and swell actions,
while still being held in position relative to the support vessels
and drilling sites in the surrounding area.
[0010] A modern FPSO used to service subsea production wells 110
and/or injection wells 111 will typically have a keel length of
between about 900 and 1,500 feet, with a storage section 109 having
a storage capacity of between about 500,000 barrels and about four
million barrels disposed beneath the ship's deck surface. In
vessels where the storage volume is essentially zero but all of the
other facilities and equipment packages necessary for injection and
production operations are present, the vessel is instead called a
floating production unit (FPU).
[0011] While relatively effective in deepwater environments, those
of ordinary skill in the art will appreciate that FPSO systems also
have several major drawbacks. For example, a modern FPSO can take
as long as eight to ten years from start-up to completion before it
can be used at sea, and the total cost associated with
manufacturing the vessel can run in excess of one billion
dollars.
[0012] Moreover, since an FPSO is so large and expensive to
manufacture, only very large field operations (e.g., those
producing about 50,000 barrels a day or more) will economically
justify an operator's investment in such a vessel. Consequently, a
great many lesser fields (for example, fields have the capacity to
yield only about 10,000 barrels a day) are known by explorers to
contain reserves, but are not being worked by producers because the
cost of production using an FPSO would exceed the profits that
could be obtained from recoverable reserves.
[0013] Past efforts to provide simpler, less expensive vessel
docking systems include U.S. Pat. No. 853,328 to Wiking, which
discloses a pontoon-type floating dock, which captures and lifts
one or more vessels so as to serve as an extension of an attendant
dry dock. The Wiking system is deficient, however, in that it is
useful "only for small vessels," lacks the buoyant capacity to
capture and lift vessels of any significant size and weight (which
is, of course, a critical aspect of any modern exploration and
production system), and utterly fails to contemplate the coupling
of multiple deck surfaces in order to form a larger, unified deck
from which exploration and production operations can be carried
out.
[0014] Similarly, U.S. Pat. No. 6,336,419 to Breivik discloses a
barge having one or more docking stations formed at either end in
which captive ships can be docked, but fails to appreciate the
advantages of lifting and coupling two or more vessels so that
their respective deck surfaces are combined into a larger, unitary
surface from which exploration and production operations can be
carried out with maximum efficiency and safety.
[0015] There is, therefore, a need for a system and method of
exploring and producing offshore wells in such a manner that the
functions of two or more vessels can be combined to work the wells
without interruption, and where a number of closely disposed sites
can be worked simultaneously by a limited number of such
vessels.
[0016] There is also a need for a system and method by which a
centralized, floating docking station provides access to a number
of associated deck surfaces flexibly capable of meeting the
changing needs of operators during exploration and production, so
that the delay between operator investment and profit is
minimized.
[0017] There is also a need to provide a substitute for existing
floating production and storage offtake vessels that admits to safe
and reliable transfer of equipment packages (e.g., drilling
packages, testing packages, production packages, workover packages,
etc.) between and amongst associated deck surfaces, and for secure
vessel connections so that associated deck surfaces can be safely
and easily connected and/or disconnected during operations.
[0018] There is also a need to provide a surface vessel arrangement
wherein a plurality of associated deck surfaces are complementary
in function, so that unnecessary delays and undesirable safety
conditions are avoided throughout the entirety of exploration and
production.
[0019] Finally, there is a need for vessel capturing, lifting and
coupling systems that permit older, less expensive and more widely
available exploration and production vessels to participate in
offshore operations by serving as a platform from which equipment
packages and extracted hydrocarbon reserves are loaded, stored and
transported in a safe, efficient and well-organized manner.
SUMMARY OF THE INVENTION
[0020] A wet docking station for exploring and producing offshore
energy sites is provided, in which the wet docking station includes
at least: a buoyant central docking station; an adjustable buoyancy
chamber for adjusting the buoyancy of the buoyant central docking
station; and at least one subordinate docking station for capturing
and lifting at least one sea vessel.
[0021] A method of exploring and producing offshore energy sites
using a wet docking station is also provided, in which the method
includes at least: disposing a buoyant central docking station in
communication with an adjustable buoyancy chamber, wherein said
adjustable buoyancy chamber is used to adjust the buoyancy of said
buoyant central docking station; and disposing the buoyant central
docking station in communication with at least one subordinate
docking station, wherein the subordinate docking station is used to
capture and lift at least one sea vessel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a side view of a floating production and storage
offtake vessel presently known in the prior art.
[0023] FIG. 2 is a side view of an example wet docking station
according to the invention.
[0024] FIG. 3 is a rear view of a combined central stabilizer and
bumper guard structure useful with the wet docking station depicted
in FIG. 2.
[0025] FIG. 4 is the wet docking station depicted in FIG. 3, shown
after two vessels have been captured within the docking
station.
[0026] FIG. 5 is a rear view of a portion of the docking station
depicted in FIG. 4, shown with two ships that have already been
captured being lifted and pinched between a central divider and a
plurality of side stabilizers.
[0027] FIG. 6 is an elevated depiction of a wet docking station
according to the invention.
[0028] FIG. 7 is an elevated view of a wet docking station having
additional storage capacity according to the invention.
[0029] FIG. 8 is a rear view of a wet docking station used to load
and offload equipment, material, supplies, etc., between the decks
of captured vessels.
[0030] FIG. 9 is a front view of a wet docking station having
additional storage capacity and additional deck surface for
accommodating and storing equipment packages, technical facilities,
etc.
[0031] FIG. 10 is a top view of an alternative wet docking system
according to the invention, in which a plurality of individual wet
docks are coupled together.
[0032] FIG. 11 is a front view of the wet docking station depicted
in FIG. 10, wherein vessels of different sizes are shown captured,
lifted and coupled together, so that associated deck surfaces are
combined into a single, unitary whole.
DETAILED DESCRIPTION
[0033] The present invention is directed to an offshore docking
system in which a number of multifunctional sea vessels are
captured, lifted and coupled in a central "wet" dock using one or
more adjustable buoyancy chambers. For the purposes of this
application, a wet docking station is defined as a docking station
capable of rising up from beneath sea level to capture and couple
one or more vessels, so that greater deck and storage space, and a
more flexible combination of facilities and equipment packages, is
achieved.
[0034] The buoyancy chambers are generally disposed beneath the
hulls of either the wet docking station or the vessels captured
within the dock (or both), so that the buoyancy chambers are
capable of transmitting a significant lifting force toward the
bottom of the hulls; however, in some embodiments the adjustable
buoyancy chambers are disposed within the hull of the docking
station itself, with external buoyancy chambers being added to the
system on an as-needed basis.
[0035] Once the captured vessels are lifted and secured within the
central docking station, their deck surfaces are then coupled to
one another, so that equipment packages, technical facilities,
etc., can be quickly transferred between the vessels in a safe and
controlled manner, thereby reducing the risk of accidents and
collisions, as well as establishing a large combined deck surface
from which operations can be carried out. Consequently, project
time horizons are reduced, and a flexible, modularized exploration
and production system is achieved on a cost effective basis.
[0036] In the specific, non-limiting embodiment of the invention
depicted in FIG. 2, for example, a sea vessel docking station
according to the invention comprises a rib shaped support hull or
other central docking station 200; one or more adjustable buoyancy
chambers 201, which are held or connected to the bottom of the
docking station 200 by adjustment control means 202; and one or
more vessel capturing stations 203 used to capture incoming vessels
prior to lifting and coupling them together.
[0037] In practice, adjustable buoyancy chamber 201 and the vessel
capturing stations 203 rise up from beneath the hull of a vessel
and apply a significant lifting force, thereby lifting, supporting
and pinching the vessel together in the arms of the docking station
200, so that a mutual deck surface can be established between the
newly captured vessel and other, previously captured vessels in a
safe and reliable manner.
[0038] In the depicted embodiment, the depth at which adjustable
buoyancy chamber 201 is disposed beneath the wave surface is
controlled by an adjustable control means 202, though in other
embodiments adjustable buoyancy chamber 201 is disposed in direct
communication with support hull 200. In still other embodiments,
either (or both) of adjustable buoyancy chamber 201 and adjustment
control means 202 are withheld from the system, and support hull
200 is instead equipped with one or more buoyancy chambers (such as
an internal ballast system), so that the depth of the docking
station is controlled by either flooding or evacuating the buoyancy
chambers disposed in support hull 200 with a fluid, such as sea
water, pneumatic pressure supplied from an outside source, etc.
[0039] During this process, the central docking station can be
dynamically positioned with respect to surrounding vessels and
buoys (not shown), fixed to a turret so that the station revolves
around a mooring, or simply tied off to suction anchors 204 or the
like using one or more sets of mooring lines 205.
[0040] As seen in the example embodiment depicted in FIG. 3,
portions of the central docking station 300 comprise a divider 301
disposed between the capturing stations, so that captured vessels
cannot collide or transmit wave forces toward other vessels
captured in the docking station 300. In other embodiments, outer
portions of divider 301 and the inner portions 302 of the capturing
stations are fitted with ship bumpers 303 or the like, so that
captured vessels can be lifted and pinched against the bumpers 303
by, for example, tying off the vessel against the bumpers using
ropes or chains, or by inwardly pivoting an arm of the station
about a pivoting member 305.
[0041] In a further embodiment, captured vessels are lifted and
held in place against the ship bumpers 303 by means of an
adjustable buoyancy chamber 304. In cases where the captured
vessels are of significantly different sizes, an adjustable
buoyancy chamber 304 disposed in the capturing station can be used
to lift the decks of the vessels to a similar elevation, so that a
mutual deck surface can be established between them, and equipment
packages and the like can be transferred from ship to ship.
[0042] As seen in the example embodiments depicted in FIGS. 4 and
5, however, vessels of similar size and dimensions 401, 402 and
501, 502, respectively, can be captured and controlled in such a
manner that adjoining deck surfaces are disposed in a relatively
even and level plane without requiring a secondary buoyancy chamber
to lift either vessel. In such embodiments, portions 400, 500 of
the docking station will still comprise primary buoyancy chambers
used for raising the station up from beneath the vessels and
initiating the capturing process, and for sinking the station back
into the sea so that captured vessels can be maneuvered away to
make room for other, newly acquired vessels.
[0043] Turning now to the detailed, non-limiting embodiment
depicted in FIG. 6, a wet docking station 600 according to the
invention is shown which illustrates how two or more vessels can be
captured, lifted and coupled in the station so that a unitary,
multifunctional, sea-worthy vessel is created for furthering an
exploration and production operation.
[0044] A principle advantage of the system is that the total deck
surface area of a smaller vessel 601 can effectively be increased
by adding the deck surface area of a second, adjoining vessel 602
that has been captured, lifted and coupled to the first vessel 601.
For example, if first captured vessel 601 has a working deck space
of about 150 in length and about 50 feet wide, then the total
available workspace on that vessel is about 7,500 square feet.
Likewise, if second captured vessel 602 has a working deck space of
about 200 feet in length and 70 feet wide, then the total available
workspace is about 14,000 square feet. By lifting and coupling the
two vessels together, however, a total available working deck space
of about 21,500 square feet (7,500 plus 14,000) is achieved.
[0045] In this particular example embodiment, first captured vessel
601 is equipped with one or more of a power generator 603; a water
treatment facility 604; a water injection package 605 with
attendant water injection lines 617; and a crew housing and control
unit 606. Those of ordinary skill in the art will appreciate,
however, that virtually any number of other packages, production
and storage units, stacks of riser or drilling equipment, etc., can
instead be disposed on the first vessel.
[0046] While such a vessel would be helpful for supporting an
existing exploration and production project, it lacks many of the
structures and technical packages necessary to initiate and
complete an ongoing operation. For example, first captured vessel
601 lacks an oil and gas separator, gas compression and injection
units, an oil treatment unit, and many other facilities and
packages customarily found on floating storage and offtake vessels
that might prove useful during operations. According to the
invention, therefore, a second vessel 602 is captured, raised to an
essentially equal deck height as the first vessel, and then coupled
to either the first vessel or the docking station so that personnel
can safely and reliably enjoy the advantages of both vessels
simultaneously, even as the two coupled vessels and the docking
station proceed as a single, unitary whole.
[0047] In the depicted embodiment, for example, captured second
vessel 602 further comprises a helicopter pad 607; a gas compressor
608 having attendant gas injection lines 616; oil, gas and/or water
separators 609; a gas treatment unit 618; an oil treatment unit
610; a gas flare boom 611; and a plurality of oil production lines
615. In one embodiment, the vessel is controlled by ballasting at
least part of the docking station down into the sea, and then
floating the vessel over the docking station 600 so that it can be
captured and raised to the deck height of the first vessel.
Alternatively, at least part of the docking station 600 is
ballasted down into the sea, moved beneath the hull of the vessel
intended for capture, and then raised, so that the vessel is now
securely held in the dock, and the facilities and packages disposed
thereupon can be used by operators in conjunction with the
facilities and packages disposed on the first captured vessel
601.
[0048] In this particular embodiment, since all of the technical
facilities and equipment packages necessary to carry out operations
in a typical exploration and production project are provided, it
might not be necessary for any other vessels to be brought in with
additional equipment in order to complete the operation. However,
should it turn out that additional facilities or packages are in
fact required, one (or both) of the vessels presently captured in
the station can be released, and a third ship, a fourth ship, and
so on, can be captured and employed to achieve the advantages of
their technical configurations.
[0049] In this embodiment, the station releases a captured vessel
by employing a protocol that is essentially the reverse of the
capturing process. For example, if it is desirable to release
second captured vessel 602 from the station for some reason, at
least part of the station beneath the vessel is ballasted down
until the vessel is free of the frictional forces holding the
vessel between central stabilizer 613 and side docking ribs 614;
the vessel is then moved out of the station under its own power,
towed out of the station using a support vessel, or simply held in
place using either a tethering system or dynamic positioning
techniques while the station is moved out from under the
vessel.
[0050] In the example embodiment of FIG. 7, a barge-like storage
tank 700 is equipped with a ribbed hull docking station comprising
a central stabilizer 701 and a plurality of side stabilizers 702,
which define a first vessel docking port 703 and a second vessel
docking port 704, as described above with respect to various other
embodiments. In this embodiment, however, a large fluid storage
facility 705 is also provided, wherein about 500,000 barrels of
fluid can be stored during production, and then discharged into a
tanker when its storage capacity has been reached or is otherwise
convenient for operators. The entire docking station, or,
alternatively, part of the docking station can be submerged beneath
sea level 705 at any given time, so long as the station remains
sufficiently stable to accommodate the lifting and coupling of
captured vessels.
[0051] As mentioned, it may at times be desirable to replace or
remove equipment packages disposed on one or more of the vessels
captured in the station. Thus, FIG. 8 depicts another embodiment of
a sea vessel docking station according to the invention, wherein
the system's improved loading and offloading capabilities are
emphasized.
[0052] As in previous embodiments, an offshore wet dock 800, within
which a plurality of vessels 801, 802 are captured, is provided,
comprising two or more docking stations formed by a plurality of
docking station inner surfaces 807, 808 and a plurality of
lockable, pivoting side stabilizers 805, 806. The buoyancy of wet
dock 800 is controlled by either an external buoyancy chamber, or
by one or more internal ballast chambers used to either improve or
retard the dock's buoyancy characteristics, depending on whether
water or another fluid is being pumped into or evacuated from the
ballast chambers. Those of ordinary skill in the art will
appreciate that such ballast chambers satisfy the definition of the
term "adjustable buoyancy chamber" within the context of claimed
design.
[0053] In such embodiments, the functionality of secondary buoyancy
chambers 809, 810 can be replaced by a more conventional,
mechanical lifting system (not shown) without departing from the
scope of the invention. Other presently contemplated methods of
leveling captured vessels' decks include holding the height of one
of the deck surfaces in a static position while raising the deck
surface of a second vessel, and/or holding one of the deck surfaces
at a static height and then lowering the deck surface of the other
vessel. Since many ships already include ballast systems that admit
to the raising and lowering of a deck surface by raising or
lowering the profile of the entire vessel, it is also possible to
utilize that functionality and avoid the need for a secondary
lifting system contained within the docking station in order to
level the deck surfaces of captured vessels.
[0054] In this particular embodiment, wet dock 800 is further
equipped with a docking station connecting member 811, comprised of
one or more vertical support members 812, a conveyer belt and
roller assembly 813, and, in the depicted embodiment, a spool for
winding and unwinding cable or chain, etc., in response to winch
system 814, 817, which feeds its line over pulley 816 so that cargo
or equipment package 815 can be transferred from the deck of
captured vessel 802 down onto the surface of conveyer belt and
roller assembly 813. The cargo or equipment package can then be
moved closer to the deck surface 818 of captured vessel 801, or
else moved on board the deck surface 818 of captured vessel 801, so
that operators can begin to use the equipment package 815 while
captured vessel 802 is allowed to leave the docking station.
[0055] In a detailed example of this embodiment, captured vessel
802 has a testing package aboard that is useful in conjunction with
an exploration package stored on vessel 801. By coupling the raised
deck surface of vessel 802 with the lower deck surface of the
docking station 800, the testing package is transferred down onto
the deck surface of the docking station by means of an elevated
winch and pulley system, a hoist, or a small crane or the like.
Continuing the process, vessel 802 is then removed from the docking
station, and a third ship is captured and raised in its place, so
that additional equipment can be transferred onto the deck of
docking station 800.
[0056] As seen in the example embodiment of FIG. 9, a larger
intermediate deck surface 907 disposed above the entirety (or part)
of the docking station hull 900 will result in the creation of a
large, stable platform surface having a total area greater than
even the combined deck surfaces 908, 909 of the captured vessels
901, 902 from which additional operations can be carried out. In
some embodiments, a portion of wet dock 900 is large enough to
serve as a fluid storage container, which can be fully or partially
submerged beneath sea level until such time as a transfer of stored
fluids becomes either desirable or necessary (e.g., in the case
where the storage container becomes full of stored fluid during the
course of operations).
[0057] In the example embodiment depicted in FIG. 10, the
general-purpose hull of the prior embodiments is replaced with a
floating frame 1000, within which an individual vessel can be
captured. Additional floating frames 1001, 1002, each of which
house other captured vessels 1003, 1004, are then connected to the
first floating frame 1000 using a known connecting means 1006
(e.g., ship bumpers, connecting rods, etc.), so that the resultant
structure becomes coupled into a single, modularized whole.
[0058] In some embodiments, the entire structure is supported by an
external adjustable buoyancy chamber (not shown); in other
embodiments, however, the structure is not supported by a separate
buoyancy chamber, and instead relies on its own ballast and
weighting systems to raise and lower the frames beneath desired
vessels' hulls prior to capture.
[0059] In still other embodiments (see, for example, FIG. 11),
after the deck surfaces of the captured vessels 1103, 1104 are
raised to a desired height, a mutual deck surface 1111 or other,
similar structure is fitted over the topmost surfaces of each ship.
In this manner, the two vessels 1103, 1104 are coupled, so that
necessary operations can be carried out while the system continues
to safely perform at sea as a single unitary structure. For
example, once the vessels 1103, 1104 have been coupled together,
operators can thereafter use all of the various equipment packages
(e.g., drilling packages, testing packages, production packages,
workover packages, etc.) originally stored on the individual ships
as if the packages were originally all present on a single
FPSO.
[0060] In practicing the invention, a number of older, less
expensive vessels can be used to duplicate the effectiveness of a
far more costly, fully equipped, modern FPSO vessel, which in
practice is often unavailable on short notice, or infeasible due to
financial considerations. A principal advantage of the invention in
this respect is that ships of any size, age and hull design can be
captured and coupled in the docking station, while the docking
station itself proceeds at sea, essentially performing as an
integrated, unitary housing within which various ships are
serviced. Since the captured ships collectively contain all of the
equipment and design packages required to satisfy the many
different needs of an exploration and production vessel, piecemeal
assembly of the technical packages required for any particular
operation is achieved, without the need for a large, expensive,
exploration and production vessel that contains all of the
equipment that night ever be useful in an operation irrespective of
whether it is actually needed in the application at hand.
[0061] In short, the invention disclosed herein provides a unique
system and method by which a central docking station can capture,
lift and couple a plurality of sea vessels, so that a flexible,
modularized production system is achieved on a cost effective
basis. The capabilities of a number of older, less expensive
vessels can be combined to achieve an effective FPSO substitute
that allows lower producing fields to be explored and produced in a
profitable manner. Time horizons between initiation and
consummation of field operations are reduced, and older vessels
that might otherwise be scrapped or retired are again made useful
and seaworthy.
[0062] The foregoing specification is provided for illustrative
purposes only, and is not intended to describe all possible aspects
of the present invention. Moreover, while the invention has been
shown and described in detail with respect to several exemplary
embodiments, those of ordinary skill in the pertinent arts will
appreciate that minor changes to the description, and various other
modifications, omissions and additions may also be made without
departing from either the spirit or scope thereof.
* * * * *