U.S. patent application number 13/383438 was filed with the patent office on 2012-05-10 for semi-submersible floating structure.
Invention is credited to Yile Li, You Sun Li, Stergios Liapis, Joao Paulo Juliao Matsuura, Arno Laurentius Michael Van Den Haak.
Application Number | 20120114421 13/383438 |
Document ID | / |
Family ID | 43449688 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120114421 |
Kind Code |
A1 |
Van Den Haak; Arno Laurentius
Michael ; et al. |
May 10, 2012 |
SEMI-SUBMERSIBLE FLOATING STRUCTURE
Abstract
A floating system comprising a plurality of buoyant columns, a
top portion of the columns extending above a water surface, and a
bottom portion of the columns submerged in a body of water; a deck
connected to the top portion of the columns; at least one pontoon
connected to the bottom portion of at least two of the columns; a
plurality of heave plates, each heave plate connected to the bottom
portion of at least one of the columns; and a conduit connected to
the deck and extending to a bottom of the body of water.
Inventors: |
Van Den Haak; Arno Laurentius
Michael; (Houston, TX) ; Li; Yile; (Katy,
TX) ; Li; You Sun; (Houston, TX) ; Liapis;
Stergios; (Bellaire, TX) ; Matsuura; Joao Paulo
Juliao; (Houston, TX) |
Family ID: |
43449688 |
Appl. No.: |
13/383438 |
Filed: |
July 6, 2010 |
PCT Filed: |
July 6, 2010 |
PCT NO: |
PCT/US10/41048 |
371 Date: |
January 11, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61224959 |
Jul 13, 2009 |
|
|
|
Current U.S.
Class: |
405/200 |
Current CPC
Class: |
B63B 2035/448 20130101;
B63B 35/4413 20130101; B63B 2001/128 20130101; B63B 2039/067
20130101; B63B 1/107 20130101 |
Class at
Publication: |
405/200 |
International
Class: |
E02B 17/08 20060101
E02B017/08 |
Claims
1. A floating system comprising: a plurality of buoyant columns, a
top portion of the columns extending above a water surface, and a
bottom portion of the columns submerged in a body of water; a deck
connected to the top portion of the columns; at least one pontoon
connected to the bottom portion of at least two of the columns; a
plurality of heave plates, each heave plate connected to the bottom
portion of at least one of the columns; and a conduit connected to
the deck and extending to a bottom of the body of water.
2. The system of claim 1, further comprising drilling equipment on
the deck.
3. The system of claim 1, further comprising anchor lines connected
to the bottom portion of at least two of the columns
4. The system of claim 1, wherein the conduit comprises a top
tensioned riser.
5. The system of claim 1, further comprising a dry tree connected
to a top end of the conduit, the dry tree installed above the water
surface.
6. The system of claim 1, wherein the pontoons are buoyant.
7. The system of claim 1, wherein the plurality of buoyant columns
comprises from 3 to 6 buoyant columns
8. The system of claim 1, wherein the system has a displacement of
at least about 25,000 tons.
9. The system of claim 1, further comprising supporting beams, each
beam connected to the heave plate and the buoyant column.
10. The system of claim 1, wherein the pontoon is connected to the
column above a location of the heave plate.
11. The system of claim 1, wherein the pontoon is connected to the
column below a location of the heave plate.
12. The system of claim 1, further comprising at least one
telescopic column extenders connected to the column at a first end
and the heave plate at a second end.
13. The system of claim 12, wherein the telescopic column extenders
are extendable from a first position at least partially within the
column to a second position outside the column.
14. The system of claim 1, further comprising a column extender
stabilizer connected to at least two of the column extenders.
Description
FIELD OF THE INVENTION
[0001] Embodiments disclosed herein generally relate to floating
structures used in an offshore environment.
BACKGROUND OF THE INVENTION
[0002] Top tensioned risers with dry trees located on the surface
structure allow direct vertical access to subsea wells.
[0003] Spar type structures have sufficiently low motions so that
they can be used with top tensioned risers and dry trees. Spars
have the disadvantage that they have to be towed into location
horizontally, then upended in place, and the decks lifted onto the
spar structure.
[0004] Semisubmersibles generally have too much motion to be used
with top tensioned risers and dry trees, so they are traditionally
used with steel catenary risers that tie back to subsea wet trees.
Semisubmersibles have the advantage over spars that their decks can
be installed on shore, and then the structure with decks can be
towed into location.
[0005] U.S. Pat. No. 3,397,545 discloses a movable marine structure
including buoyant columns having damping plates and fins. U.S. Pat.
No. 3,397,545 is herein incorporated by reference in its
entirety.
[0006] U.S. Pat. No. 5,558,467 discloses a deep water offshore
apparatus for use in oil drilling and production in which an upper
buoyant hull of prismatic shape is provided with a passage
longitudinally extending through the hull in which risers run down
to the sea floor, the bottom of the hull being located at a
selected depth dependent upon the wind, wave, and current
environment at the well site, which significantly reduces the wave
forces acting on the bottom of the hull, a frame structure
connected to the hull bottom and extending downwardly and
comprising a plurality of vertically arranged bays defined by
vertically spaced horizontal water entrapment plates and providing
open windows around the periphery of the frame structure, the
windows providing transparency to ocean currents and to wave motion
in a horizontal direction to reduce drag, the vertical space
between the plates corresponding to the width of the bay window,
the frame structure being below significant wave action whereby
wave action thereat does not contribute to heave motion of the
apparatus but inhibits heave motion, the frame structure serving to
modify the natural period and stability of the apparatus to
minimize heave, pitch, and roll motions of the apparatus. A keel
assembly at the bottom of the frame structure with ballast chambers
for enabling the apparatus to float horizontally and for
stabilization of the apparatus against tilting in vertical
position, and taut anchor lines connected to the apparatus at a
location of relatively little cyclic movement of the apparatus, the
said lines being connected to suitable anchors. U.S. Pat. No.
5,558,467 is herein incorporated by reference in its entirety.
[0007] U.S. Pat. No. 7,086,809 discloses an apparatus for use in
offshore oil or gas production in which a plurality of vertical
stabilizing columns are supported on a submerged horizontal water
entrapment plate is provided to support minimum offshore oil and
gas production facilities above a subsea wellhead, or subsea
processing facilities, or a submarine pipeline, and whose main
function is to provide power or chemicals or to perform other
operations such as compression, injection, or separation of water,
oil and gas. The apparatus is maintained in the desired location by
a plurality of mooring lines anchored to the sea-bed. The
respective size and shape of the columns and water entrapment plate
are designed to provide sufficient buoyancy to carry the weight of
all equipment on the minimum floating platform and mooring lines,
umbilical and risers attached to it, and to minimize the platform
motion during normal operations. U.S. Pat. No. 7,086,809 is herein
incorporated by reference in its entirety.
[0008] U.S. Pat. No. 7,281,881 discloses an apparatus for use in
offshore oil or gas production in which a plurality of vertical
stabilizing columns are supported on a submerged horizontal water
entrapment plate to support minimum offshore oil and gas production
facilities above a subsea wellhead, or subsea processing
facilities, or a submarine pipeline, and whose main function is to
provide power or chemicals or to perform other operations such as
compression, injection, or separation of water, oil and gas. The
apparatus is maintained in the desired location by a plurality of
mooring lines anchored to the sea-bed. The respective size and
shape of the columns and water entrapment plate are designed to
provide sufficient buoyancy to carry the weight of all equipment on
the minimum floating platform and mooring lines, umbilical and
risers attached to it, and to minimize the platform motion during
normal operations. U.S. Pat. No. 7,281,881 is herein incorporated
by reference in its entirety.
[0009] U.S. Pat. No. 7,191,836 discloses compliant variable tension
risers to connect deep-water subsea wellheads to a single floating
platform. The variable tension risers allow several subsea
well-heads, in water depths from 4,000 to 10,000 feet, at lateral
offsets from one-tenth to one-half of the depth, to tie back to a
single floating dry tree semi-submersible platform. Also disclosed
are methods to counter buoyancy and install variable tension risers
using a weighted chain ballast line. U.S. Pat. No. 7,191,836 is
herein incorporated by reference in its entirety.
[0010] The "Hydrodynamics of Dry Tree Semisubmersibles" paper by
John Murray, Arcandra Tahar and Chan K. Yang, published by The
International Society of Offshore and Polar Engineers (ISOPE) in
July 2007, discloses a hydrodynamics analysis of a conceptual dry
tree semisubmersible for drilling and production platforms.
Computational analysis shows that the hull form of the dry tree
semisubmersible can be optimized to control the cancellation
period, magnitude of the heave RAO below the cancellation period
and the heave natural period. The relative areas of the column and
pontoon are varied to demonstrate the global effects on the
hydrodynamic forces acting in these structural components while the
area of the heave plate is kept constant. Results show that by
keeping the displaced volume of the hull constant the relative
areas of the column and pontoon can be varied to affect the
magnitude of the hydrodynamic forces on the columns and pontoon and
thus the shape of the heave RAO. The "Hydrodynamics of Dry Tree
Semisubmersibles" paper is herein incorporated by reference in its
entirety.
[0011] There are needs in the art for one or more of the following:
offshore structures to accommodate a number of riser
configurations; a lower cost offshore structure; a direct vertical
access offshore structure; an offshore structure that allows for
quayside topsides installation; an offshore structure with reduced
heave; an offshore structure connected to one or more top tensioned
risers; an offshore structure from which to do drilling operations;
a semisubmersible offshore structure with reduced motions; and/or a
semisubmersible offshore structure with drilling operations.
SUMMARY OF INVENTION
[0012] One aspect of the invention provides a floating system
comprising a plurality of buoyant columns, a top portion of the
columns extending above a water surface, and a bottom portion of
the columns submerged in a body of water; a deck connected to the
top portion of the columns; at least one pontoon connected to the
bottom portion of at least two of the columns; a plurality of heave
plates, each heave plate connected to the bottom portion of at
least one of the columns; and a conduit connected to the deck and
extending to a bottom of the body of water.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1A shows an offshore floating structure in accordance
with embodiments disclosed herein.
[0014] FIG. 1B shows a cross-sectional view of the offshore
floating structure of FIG. 1A.
[0015] FIG. 1C shows a close-up view of a portion of FIG. 1B.
[0016] FIG. 2 shows an offshore floating structure in accordance
with embodiments disclosed herein.
[0017] FIG. 3 shows an offshore floating structure in accordance
with embodiments disclosed herein.
[0018] FIG. 4a shows an offshore floating structure in accordance
with embodiments disclosed herein.
[0019] FIG. 4b shows an offshore floating structure in accordance
with embodiments disclosed herein.
DETAILED DESCRIPTION
[0020] FIGS. 1A & 1B:
[0021] Referring to FIGS. 1A and 1B, a view of a floating system
100 according to embodiments of the present disclosure is shown.
System 100 is floating in a body of water 120 having surface 122
and floor 124. In this embodiment, system 100 includes buoyant
columns 102 connected at their base by buoyant pontoon members 104,
and connected at their top by deck 106. Drilling equipment 108 as
is known in the art may be disposed on deck 106. Heave plates 110
are fixed to the base of columns 102, and may optionally be
attached to pontoon members 104. Anchor lines 112 are connected to
the base of columns 102 and to anchors (not shown) on floor
124.
[0022] Conduit 116, such as a riser or umbilical, connects
equipment 114 at floor 124 to dry tree 134 on deck 106. Equipment
114 could be a wellhead, liner hanger, subsea BOP, manifold, pump,
separator, or other equipment as is known in the art.
[0023] As shown in FIG. 1B, there are four columns 102. In other
embodiments, there could be from 3 to about 8 columns, for example
from about 4 to about 6 columns.
[0024] As shown in FIG. 1B, there are four plates 110. In other
embodiments, there could be from 2 to about 8 plates, for example
from about 4 to about 6 plates. Plates 110 could be attached to
every column 102, or every other column 102. Although plates 110
are shown as circular plates, in other embodiments, plates 110
could be oval, square, diamond, rectangular, triangular,
pentagonal, hexagonal, octagonal, or other polygonal shaped plates,
for example polygonal shaped plates having from about 3 to about 10
sides, for example from about 4 to 8 sides.
[0025] As shown in FIG. 1B, there are 8 anchor lines 112, 2
connected to each column 102. In other embodiments, there could be
from about 4 to about 36 anchor lines, for example from about 6 to
about 24 anchor lines.
[0026] As shown in FIG. 1B, only one conduit 116 is illustrated. In
other embodiments, there could be from about 1 to about 20
conduits, for example from about 4 to about 10 conduits. Conduits
could be top tensioned risers, drilling conduits, or other conduits
as are known in the art.
[0027] In some embodiments, conduit 116 may be a top tensioned
riser connected a tensioner (not shown) located on deck 106.
Tensioner may have a stroke range from about 5 to about 50 feet,
for example from about 10 to about 28 feet.
[0028] As shown in FIG. 1B, columns 102 are illustrated having a
circular cross section. In other embodiments, columns 102 may have
a square, rectangular, oval, triangular, or other shaped cross
section.
[0029] In some embodiments, columns 102 have a diameter from about
10 to about 80 feet, for example from about 20 to 60 feet, or from
about 40 to about 50 feet.
[0030] In some embodiments, columns 102 have a length from about 50
to about 200 feet, for example from about 75 to 150 feet, or from
about 100 to about 125 feet.
[0031] In some embodiments, the spacing between adjacent columns
102 is from about 75 to about 400 feet, for example from about 100
to 300 feet, or from about 150 to about 200 feet.
[0032] In some embodiments, plates 110 have a diameter from about
20 to about 200 feet, for example from about 40 to 150 feet, or
from about 50 to about 100 feet.
[0033] In some embodiments, system 100 has a draft (submerged
portion) from about 50 to about 200 feet, for example from about 60
to 150 feet, or from about 75 to about 125 feet.
[0034] In some embodiments, system 100 has a displacement from
about 10,000 to about 80,000 tons, for example from about 20,000 to
about 70,000 tons, or from about 30,000 to about 60,000 tons.
[0035] FIG. 1C:
[0036] Referring to FIG. 1C, a close up view of one column 102 and
plate 110 is shown, where the column 102 is connected to two
pontoons 104. Plate 110 is attached to inner 130, middle 132, and
outer 134 circumferential support beams. Plate 110 is also attached
to radial support beams 140.
[0037] Plate 110 is shown with a square shape, but other shapes are
also suitable, as discussed above.
[0038] FIG. 2:
[0039] Referring to FIG. 2, system 200 is illustrated. System 200
is floating in a body of water 220 having surface 222 and floor
224. In this embodiment, system 200 includes buoyant columns 202
connected above their base by buoyant pontoon members 204, and
connected at their top by deck 206. Various equipment 208, such as
drilling equipment and production equipment as is known in the art
may be disposed on deck 206. Heave plates 210 are fixed to the base
of columns 202, and are further attached to columns with angled
beams 250. Anchor lines 212 are connected to the base of columns
202 and to anchors (not shown) on floor 224.
[0040] Conduit 216, such as a riser or umbilical, connects
equipment 214 at floor 224 to dry tree 234 located above the water
surface and below deck 206. Equipment 214 could be a wellhead,
subsea BOP, manifold, pump, separator, or other equipment as is
known in the art.
[0041] FIG. 3:
[0042] Referring to FIG. 3, system 300 is illustrated. System 300
is floating in a body of water 320 having surface 322 and floor
324. In this embodiment, system 300 includes buoyant columns 302
connected at their base by buoyant pontoon members 304, and
connected at their top by deck 306. Various equipment 308 as is
known in the art may be disposed on deck 306. Heave plates 310 are
fixed above the base of columns 302, and are further attached to
columns with angled beams 350. Anchor lines 312 are connected to
the base of columns 302 and to anchors (not shown) on floor
324.
[0043] Conduit 316, such as a riser or umbilical, connects
equipment 314 at floor 324 to dry tree 334 located near deck
306.
[0044] FIGS. 4a-4b:
[0045] Referring to FIG. 4a, system 400 is illustrated. System 400
is floating in a body of water 420 having surface 422 and floor
424. In this embodiment, system 400 includes buoyant columns 402
connected at their base by buoyant pontoon members 404, and
connected at their top by deck 406. Various equipment 408 as is
known in the art may be disposed on deck 406. Heave plates 410 are
fixed to column extenders 360 located within the base of columns
402. Anchor lines 412 are connected to the base of columns 402 and
to anchors (not shown) on floor 424.
[0046] Conduit 416, such as a riser or umbilical, connects
equipment 414 at floor 424 to dry tree 434 located near deck
406.
[0047] As shown in FIG. 4a, column extenders 360 are located within
the base of columns 402, such as when system is going to be
transported from the dock to an installation location, or from the
installation location back to the dock.
[0048] In FIG. 4b, column extenders 460 have been lowered from
within the base of columns 402, to place plates 410 at a greater
depth below the water surface, for example at a depth of 100 to 300
feet below the water surface.
[0049] In some embodiments, connector 462 may be provided to
connect and provide structural support to column extenders 460.
Connector 462 may be a beam, cable, rope, pontoon, or other
structures as are known in the art. Connector 462 may be attached
to column extenders 460 when column extenders 360 are located
within the base of columns 402, or connector 462 may be attached to
column extenders 460 after column extenders 460 have been lowered
from within the base of columns 402.
[0050] In some embodiments, system 100 has a displacement of at
least about 20,000 tons, for example from about 25,000 to 150,000
tons, or from about 30,000 to 100,000, or from about 35,000 to
50,000 tons.
Illustrative Embodiments
[0051] In one embodiment, there is disclosed a floating system
comprising a plurality of buoyant columns, a top portion of the
columns extending above a water surface, and a bottom portion of
the columns submerged in a body of water; a deck connected to the
top portion of the columns; at least one pontoon connected to the
bottom portion of at least two of the columns; a plurality of heave
plates, each heave plate connected to the bottom portion of at
least one of the columns; and a conduit connected to the deck and
extending to a bottom of the body of water. In some embodiments,
the system also includes drilling equipment on the deck. In some
embodiments, the system also includes anchor lines connected to the
bottom portion of at least two of the columns In some embodiments,
the conduit comprises a top tensioned riser. In some embodiments,
the system also includes a dry tree connected to a top end of the
conduit, the dry tree installed above the water surface. In some
embodiments, the pontoons are buoyant. In some embodiments, the
plurality of buoyant columns comprises from 3 to 6 buoyant columns
In some embodiments, the system has a displacement of at least
about 25,000 tons. In some embodiments, the system also includes
supporting beams, each beam connected to the heave plate and the
buoyant column In some embodiments, the pontoon is connected to the
column above a location of the heave plate. In some embodiments,
the pontoon is connected to the column below a location of the
heave plate. In some embodiments, the system also includes at least
one telescopic column extenders connected to the column at a first
end and the heave plate at a second end. In some embodiments, the
telescopic column extenders are extendable from a first position at
least partially within the column to a second position outside the
column. In some embodiments, the system also includes a column
extender stabilizer connected to at least two of the column
extenders.
[0052] While the invention has been described with respect to a
limited number of embodiments, those skilled in the art, having
benefit of this disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the invention
as disclosed herein. Accordingly, the scope of the invention should
be limited only by the attached claims.
* * * * *