WO2016114820A1 - Plateformes en mer semi-submersibles à fort tirant d'eau flottantes et procédés d'assemblage et de déploiement de celles-ci - Google Patents

Plateformes en mer semi-submersibles à fort tirant d'eau flottantes et procédés d'assemblage et de déploiement de celles-ci Download PDF

Info

Publication number
WO2016114820A1
WO2016114820A1 PCT/US2015/044861 US2015044861W WO2016114820A1 WO 2016114820 A1 WO2016114820 A1 WO 2016114820A1 US 2015044861 W US2015044861 W US 2015044861W WO 2016114820 A1 WO2016114820 A1 WO 2016114820A1
Authority
WO
WIPO (PCT)
Prior art keywords
deck
hull
platform
draft
columns
Prior art date
Application number
PCT/US2015/044861
Other languages
English (en)
Inventor
John James Murray
Original Assignee
Bp Corporation North America Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bp Corporation North America Inc. filed Critical Bp Corporation North America Inc.
Publication of WO2016114820A1 publication Critical patent/WO2016114820A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B77/00—Transporting or installing offshore structures on site using buoyancy forces, e.g. using semi-submersible barges, ballasting the structure or transporting of oil-and-gas platforms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B63B35/4413—Floating drilling platforms, e.g. carrying water-oil separating devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B75/00—Building or assembling floating offshore structures, e.g. semi-submersible platforms, SPAR platforms or wind turbine platforms
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
    • E02B17/021—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto with relative movement between supporting construction and platform
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/04—Equipment specially adapted for raising, lowering, or immobilising the working platform relative to the supporting construction
    • E02B17/06—Equipment specially adapted for raising, lowering, or immobilising the working platform relative to the supporting construction for immobilising, e.g. using wedges or clamping rings
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/04—Equipment specially adapted for raising, lowering, or immobilising the working platform relative to the supporting construction
    • E02B17/08—Equipment specially adapted for raising, lowering, or immobilising the working platform relative to the supporting construction for raising or lowering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B63B2021/003—Mooring or anchoring equipment, not otherwise provided for
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B63B2035/442—Spar-type semi-submersible structures, i.e. shaped as single slender, e.g. substantially cylindrical or trussed vertical bodies
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0039—Methods for placing the offshore structure
    • E02B2017/0047—Methods for placing the offshore structure using a barge

Definitions

  • This disclosure relates generally to floating offshore structures. More particularly, this disclosure relates to buoyant semi-submersible offshore platforms for offshore drilling and production operations. Still more particular, the disclosure relates to buoyant semi-submersible offshore platforms having increased draft and associated stability, while being able to be constructed dockside.
  • the draft of a floating offshore structure refers to the vertical distance between the waterline (sea surface) and the bottom of the structure when the structure is deployed in water
  • Enhanced dynamic stability provides several potential advantages including increased comfort of on-board personnel, easier operation of topsides equipment, and reduced stresses applied to structures supported by the platform such as drilling risers, production risers, etc.
  • low motion floating offshore platforms for conducting drilling and/or production operations i.e., floating offshore platforms that experience heave less than 10-15 ft.
  • TLPs and Spar platforms are two types of floating structures platforms for conducting offshore drilling and/or production operations. TLPs and Spars both experience motions sufficiently small to support top tensioned risers and dry tree production trees.
  • the TLP's vertical motions are constrained by stiff tendons that extend from the structure to the sea bed, and the Spar's vertical motions are diminished as a result of its relatively deep draft (in the order of 400 to 500 ft.) extending down to the low dynamic pressure zone.
  • Semi-submersible offshore platforms are another type of floating structure for conducting offshore drilling and/or production operations.
  • Conventional semi-submersible platforms include a hull with sufficient buoyancy to support a work platform above the surface of the water.
  • the hull is typically made of a plurality of horizontal pontoons that support a plurality of vertically upstanding columns, which in turn support the work platform.
  • the hull is divided into several closed compartments, each compartment having buoyancy that can be adjusted for purposes of flotation and trim.
  • a pumping system pumps ballast water into and out of the compartments, as desired, to adjust buoyancy.
  • Conventional shallow draft semi-submersible platforms typically have a draft less than about 100 ft. (about 30.5 m).
  • the motions of shallow draft semi-submersible platforms are usually relatively large, and thus, they are generally not suitable for top tensioned risers and dry production trees. Consequently, shallow draft semi-submersible platforms usually require the use of "catenary" risers and wet production trees disposed at the sea floor.
  • the draft of a floating semi-submersible platform can be increased to reduce motions and improve stability by lengthening the hull columns and locating the hull pontoons at a greater depth below the surface of the water.
  • Embodiments described herein include a semi-submersible platform for offshore operations.
  • the platform comprises a buoyant hull including an adjustably buoyant base and a plurality of adjustably buoyant columns extending vertically from the base.
  • the platform comprises a deck moveably coupled to the columns. The deck is configured to move vertically up and down relative to the hull.
  • Embodiments described herein also include a method for assembling a deep draft semi- submersible offshore platform.
  • the method comprises (a) floating a buoyant hull in water at a dockside location.
  • the buoyant hull has a draft less than 40 ft. at the dockside location.
  • the method comprises (b) moveably coupling a deck to the hull during (a) to form the semi-submersible offshore platform.
  • the deck is configured to move vertically relative to the hull.
  • Embodiments described herein also include a method for deploying a deep draft semi- submersible offshore platform to an offshore operating site.
  • the method comprises (a) floating the semi-submersible platform to the operating site.
  • the platform comprises a buoyant hull and a non-buoyant deck moveably coupled to the hull.
  • the hull is disposed at a draft D.
  • the method comprises (b) ballasting the hull at the operating site to increase the draft D of the hull at the operating site.
  • the method comprises (c) raising the deck vertically relative to the hull at the operating site.
  • Embodiments described herein comprise a combination of features and advantages intended to address various shortcomings associated with certain prior devices, systems, and methods.
  • the foregoing has outlined rather broadly the features and technical advantages of the invention in order that the detailed description of the invention that follows may be better understood.
  • the various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated by those skilled in the art that the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
  • Figure 1 is a schematic side view of a conventional semi-submersible platform being assembled at a dockside location
  • Figure 2 is a schematic side view of the conventional semi-submersible platform of Figure 1 deployed and anchored at an offshore operating site;
  • Figure 3 is a schematic side view of an embodiment of a deep draft semi-submersible platform in accordance with the principles described herein deployed and anchored at an offshore operating site;
  • Figure 4 is a top schematic view of the deep draft semi-submersible platform of Figure
  • Figure 5 is an enlarged partial schematic side view of one of the jack-up assemblies of Figure 4.
  • Figure 6 is a schematic side view of the deep draft semi-submersible platform of Figure 3 at a dockside location illustrating the vertical range of movement of the deck relative to the hull;
  • Figures 7A-7J are schematic side views of the deep draft semi-submersible platform of Figure 3 being assembled at a dockside location, deployed to an offshore operating site, and installed at the offshore operating site;
  • Figures 8A-8C are enlarged partial schematic side views of an embodiment of a jacking system for raising and lowering the deck of Figure 3 relative to the columns of Figure 3;
  • Figure 9 is an enlarged partial schematic side view of an embodiment of a jacking system for raising and lowering the deck of Figure 3 relative to the columns of Figure 3;
  • Figure 1 OA is a schematic top view of the deep draft semi-submersible platform of
  • Figure 3 including a plurality of column support structures
  • Figure 10B is a schematic top view of the deep draft semi-submersible platform of Figure 3 including a plurality of column support structures and deck extensions.
  • axial and axially generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis.
  • an axial distance refers to a distance measured along or parallel to the central axis
  • a radial distance means a distance measured perpendicular to the central axis.
  • TLPs Tension Leg Platforms
  • Spar platforms are two types of floating offshore structures that have sufficient dynamic stability to enable the use of top tensioned risers and dry production trees.
  • the cost of tendons can render TLPs cost prohibitive.
  • Spars may offer a better option than a TLP from a cost perspective, however, Spars pose installation challenges.
  • the hull is typically towed to the offshore operating site in a horizontal orientation (i.e., on its side), and then up-righted to a vertical orientation at the operating site under very controlled conditions.
  • the Spar topside is installed atop the hull using a heavy lift vessel. Depending on the weight of the topsides modules, multiple lifts may be required.
  • Deep draft semi-submersible platforms having a draft greater than about 150 ft. are another type of floating offshore platform capable of employing top-tensioned risers and a dry production tree.
  • deep draft semi-submersible platforms pose installation challenges. More specifically, semi-submersible offshore platforms are built by constructing the hull, and then mounting the deck to the top of the vertical columns of the hull. The location of final assembly may involve integration (i.e., installation of the deck onto the hull) at the shipyard (dockside or quayside), nearshore, or at its offshore operating site, which is typically far offshore (e.g., over 100 miles, or 161 km).
  • the deck also referred to as the topside
  • the topside is lifted and positioned atop the columns of the hull with heavy lifting equipment (e.g., heavy lift crane), and then the fully assembled semi-submersible platform is floated out to the operating site using a heavy lift or tow vessel.
  • Dockside water depths are typically on the order of 30-40 ft., and thus, for dockside integration, the hull is deballasted such that its draft is always less than the 30-40 ft. water depth.
  • an exemplary floating semi-submersible platform 10 is shown being assembled in water 1 1 at a dockside location 12.
  • Platform 10 includes a buoyant hull 20 and a deck or topside 30 disposed thereon.
  • Hull 20 includes a plurality of adjustably buoyant horizontal pontoons 21 and a plurality of adjustably buoyant vertical columns 25 extending upward from pontoons 21.
  • Hull 20 has a draft D2 0 that is limited by depth D w i2 of water 11 at dockside location 12. In other words, at dockside location 12, the draft D 2 o is less than the water depth D wl2 .
  • a heavy lift crane 40 positioned on land adjacent water 11 at the dockside location 12 lifts deck 30 upwards and positions it atop columns 25 to assemble platform 10.
  • platform 10 is floated from the dockside location 12 to the offshore operating site 14, and then hull 20 is ballasted to increase the draft D2 0 to the desired operating draft.
  • the draft D 2 o is limited by the depth D w i 2 at dockside location 12 (i.e., the draft D 2 o must be less than the depth D w i 2 at the dockside location 12).
  • hull 20 and deck 30 are separately transported offshore to the operating site 14, either by towing at a shallow draft or by transport aboard heavy lift vessels. Then, at the operating site 14, the hull 20 is ballasted down by pumping sea water into the pontoons 21 and columns 25, and then deck 30 is either lifted onto the tops of columns 25 by heavy lift cranes carried aboard a heavy lift barge or by floating deck 30 over the top of the partially submerged hull 20 using a deck barge. In either case, the procedure is typically performed far offshore in open seas, and is strongly dependent on weather conditions and the availability of a heavy lift barge.
  • hull 20 and deck 30 are separately transported to a nearshore assembly site (closer to shore than the offshore operating site 14), either by towing at a shallow draft or by floating aboard heavy lift vessels. Then, at the assembly site, hull 20 is ballasted down by pumping sea water into the pontoons 21 and columns 25, and then deck 30 is either lifted onto the tops of columns 25 by heavy lift cranes carried aboard a heavy lift barge or by floating platform 30 over the top of the partially submerged hull 20 using a deck barge. The assembled platform 10 is then floated from the nearshore assembly site to the offshore operating site 14.
  • nearshore integration is generally less expensive and less risky.
  • dockside integration is generally less expensive and less risky than both nearshore and offshore integration.
  • dockside integration provides the added advantage that it can generally be performed in a shorter timeframe than both nearshore and offshore integration.
  • dockside integration is usually not possible for deep draft semisubmersible platforms, which have relatively tall/deep columns.
  • the draft D 2 o of hull 20 is limited by depth D w i 2 of water 11 at dockside site 12, which is typically 30-40 ft. deep.
  • Hull 20 has an overall height H 2 o, and thus, hull 20 and columns 25 extend to a height 3 ⁇ 45 above the waterline 13 (i.e., surface of the water 11) that is equal to the difference between height H 2 5 and draft D 20 .
  • a sufficiently large height H 25 may exceed the maximum operating limits of the heavy lift crane 40 (i.e., crane 40 may not be able to lift the heavy deck 30 above the columns 25 and/or reach horizontally far enough to mount the deck 30).
  • crane 40 is shown operating at its maximum lifting height.
  • crane 40 cannot lift deck 30 to a height greater than height H 2 5.
  • the maximum lifting height and reach of crane 40 limits the maximum height H 2 5, which in turn limits the maximum total height H 2 o of hull 20 that can be integrated with deck 30 at dockside location 12, which has a limited water depth D wl2 .
  • the assembled platform 10 (including the heavy deck 30 mounted atop columns 25) becomes dynamically unstable and prone to capsize at the dockside location 12 as the center of gravity of the platform 10 is spaced sufficiently above the center of buoyancy of platform 10.
  • FIG. 3 an embodiment of a deep draft semi-submersible platform 100 in accordance with the principles described herein is shown.
  • platform 100 is shown deployed in a deep draft operational configuration at an offshore operating site 14 in water 11.
  • Platform 100 is anchored at the offshore operating site 14 with a mooring system 180 that limits the movements of platform 100 and maintains the position of platform 100 at the operating site 14.
  • mooring system 180 includes a plurality of catenary mooring lines 181 having upper ends coupled to hull 120 and lower ends anchored to the sea floor.
  • any suitable mooring system can be employed to limit the movements of platform 100 and maintain its position at the operating site 14.
  • platform 100 includes an adjustably buoyant hull 120, a deck support frame or sub-structure 150 moveably coupled to hull 120, and a deck or topside 160 seated on deck sub-structure 150.
  • the equipment used in oil and gas drilling or production operations such as a derrick, draw works, pumps, scrubbers, precipitators and the like are disposed on and supported by deck 160.
  • deck substructure 150 can be controllably and adjustably moved vertically up and down relative to hull 120, thereby enabling deck 160, mounted to deck sub-structure 150, to move vertically up and down relative to hull 120.
  • hull 120 includes adjustably buoyant horizontal base 130 and a plurality of adjustably buoyant columns 140 extending vertically upward from base 130.
  • base 130 of hull 120 includes a plurality of straight, elongated horizontal pontoons 131 connected end-to-end to form a closed loop base 130 with a central opening through which risers may pass up to deck 160.
  • four pontoons 131 are connected end-to-end to form a generally base 130 having four corners or nodes 133, each node 133 formed at the intersection of two pontoons 131.
  • Each pontoon 131 has the same horizontal length measured between nodes 133, and thus, base 130 has a square perimeter.
  • base 130 has a square geometry and includes four equal length pontoons 131, in other embodiments, the number of pontoons (e.g., more or less than four pontoons 131) may differ and/or the geometry of the base (e.g., base 130) may not be square (e.g., triangular, etc.). For instance, a deep draft semi-submersible platform including a hull with a triangular base and three vertical columns may be particularly suited for use in drilling operations. It should be appreciated that additional structural members not shown may be included inside or outside the pontoons (e.g., pontoons 131) to guide risers, stiffen the pontoons connections, increase the added mass effect, etc.
  • Each pontoon 131 includes ballast tanks that can be selectively ballasted and deballasted, as desired, to adjust the buoyancy of base 130 and hull 120.
  • each pontoon 131 includes a plurality of horizontally spaced bulkheads, which divide or partition the pontoon 131 into a plurality of horizontally arranged distinct compartments that can be independently and selectively ballasted and deballasted.
  • Each node 133 of base 130 underlies and supports one column 140, which extends vertically upward therefrom.
  • hull 120 includes four columns 140, one column 140 extending vertically from each node 133.
  • each column 140 includes ballast tanks that can be selectively ballasted and deballasted to adjust the buoyancy of the column 140 and hull 120.
  • each column 140 includes a plurality of vertically spaced bulkheads, which divide or partition the column 140 into a plurality of vertically stacked compartments that can be independently and selectively ballasted and deballasted as desired.
  • each column 140 extends vertically between a first or upper end 140a distal base 130 and a second or lower end 140b secured to one node 133 of base 130, and further, each column 140 has the same height Hi 4 o measured vertically between ends 140a, 140b.
  • Each pair of adjacent columns 140 is spaced apart a horizontal distance D 140 .
  • each distance Di 40 is the same.
  • Strakes 162 are provided on the outer surface of each column 140 below sub-structure 150 and deck 160. As will be described in more detail below, strakes 162 are positioned below the lowermost position of sub-structure 150 and deck 160 so as not to interfere with the vertical movement of sub-structure 150 and deck 160 relative to columns 140.
  • Hull 120 has an overall height H120 measured vertically from the bottom of hull 120 to upper ends 140a of columns 140 and a draft D120 measured vertically from the waterline 13 to the bottom of hull 140.
  • the portion of hull 120 (and columns 125) disposed above the waterline 13 has a height H 12 o> measured vertically from waterline 13 to upper ends 140a equal to the difference between overall height H120 and draft D 120 .
  • platform 100 is a deep draft semi-submersible, and thus, at operating site 14, draft D120 is greater than 150 ft., and in embodiments described herein, is preferably 150 ft. to 200 ft. Accordingly, height H120 of hull 120 is greater than 150 ft.
  • platform 100 can be constructed at dockside location 12 with a draft D120 limited to the water depth D w i 2 of 30-40 ft.
  • D120 limited to the water depth D w i 2 of 30-40 ft.
  • embodiments described herein can be sized and configured for any desired draft including, without limitation, shallow draft, deep draft, etc.
  • deck sub-structure 150 is positioned inside and extends between all four columns 140 ( Figure 3), and is moveably coupled to each column 140 with a jack-up assembly 170 ( Figures 4 and 5).
  • Deck 160 is positioned within and between columns 140 atop deck sub-structure 150.
  • deck 160 is moveably coupled to hull 120 via deck sub-structure 150 and jack-up assemblies 170.
  • deck sub-structure 150 is a structural frame (e.g., truss assembly) that is installed in place. More specifically, deck substructure 150 is installed within hull 120 (between columns 140), and moveably coupled to columns 140 at dockside location 12 prior to installation of deck 160 on hull 120.
  • each jack-up assembly 170 couples each column 140 to deck sub-structure 150.
  • each jack-up assembly 170 can comprise any system that simultaneously couples deck sub-structure 150 to each column 140 and allows sub-structure 150 to be controllably moved up and down relative to the corresponding column 140. Examples of suitable systems include those systems known in the art for moveably coupling the legs of a jack-up rig to the deck.
  • each jack-up assembly 170 includes an elongate toothed rack 171 and a powered pinion 172 that mates and engages the toothed rack 171.
  • the toothed rack 171 is vertically oriented (i.e., oriented parallel to columns 140) and fixably attached to the outer surface of the corresponding column 140 generally facing deck sub-structure 150.
  • the pinion 172 is rotatably coupled to the corner of deck sub-structure 150 immediately opposite the corresponding toothed rack 171.
  • Pinion 172 includes teeth that mate with and engage the teeth of the corresponding rack 171, and further, pinion 172 is free to rotate relative to deck sub-structure 150 and column 140.
  • each rack 171 has an upper end disposed at or proximal upper end 140a of the corresponding column 140 and a lower end disposed a height H 171 measured vertically from the bottom of hull 120.
  • jack-up assemblies 170 can move deck sub-structure 150 and deck 160 relative to hull 120 between an uppermost position 160a at upper ends 140a of columns 140 and a lowermost position 160b (shown in phantom) located at height H 171 from the bottom of hull 120.
  • the uppermost position 160a of deck 160 is spaced from the lowermost position 160b of deck 160 a vertical distance Di 6 o, which represents the maximum vertical range of movement of deck 160.
  • Height H 171 can be varied as necessary, but is preferably set to enable mounting of deck 160 on sub-structure 150 at dockside location 12 with heavy lifting equipment (e.g., crane 40) while ensuring stability of platform 100 at dockside location 12 with a draft D12 0 of about 30-40 ft. (i.e., a draft D120 less than the depth D w i2 of water 11).
  • height Hni depends on the maximum lift height H40 of crane 40 relative to bottom of hull 120 and the vertical height Hi 6 o of deck 160 itself as follows:
  • height H 171 height H 40 - height Hi 6 o
  • the vertical distance Di 6 o is preferably less than or equal to the anticipated maximum change in draft D12 0 of hull 120.
  • the minimum anticipated draft D12 0 of hull 120 is the draft D12 0 at the dockside location 12, which is set to provide nominal clearance from the seafloor at the dockside location 12 as shown in Figure 6 (typically, 30-40 ft. for most dockside locations 12) and the maximum anticipated draft D12 0 of hull 120 is the draft D12 0 at the operating site 14, which is set to accommodate the environmental conditions at the operating site 14 as shown in Figures 3 and 7J (preferably greater than 150 ft. for deep draft applications).
  • the maximum change in draft D12 0 of hull 120 is less than 120 ft., more likely between 25 ft. and 75 ft., and nominally about 50 ft.
  • vertical distance D160 is preferably less than 120 ft., more preferably between 25 ft. and 75 ft., and even more preferably about 50 ft.
  • lowermost position 160b of deck 160 is above the vertical mid-point of hull 120.
  • strakes 162 are positioned along the outer surfaces of columns 140 below lowermost position 160b of deck 160 so as not to interfere with deck 160, sub-structure 150, or jack-up assemblies 170.
  • jack-up assembly 170 is shown between sub-structure 150 and each column 140, in general, one or more jack-up assemblies (e.g., jack-up assemblies 170) can be provided between the deck sub-structure (e.g., sub-structure 150) and each column (e.g., each column 150).
  • jack-up assemblies e.g., jack-up assemblies 170
  • other jacking systems other than assembly 170 previously described can be used to couple the deck (e.g., deck 160) and substructure (e.g., sub-structure 150) to the columns (e.g., columns 140) and raise and lower the deck.
  • Alternative systems for moveably coupling the deck (e.g., deck 160) and the substructure (e.g., sub-structure 150) to the columns (e.g., columns 140) are shown in Figures 8A- 8C and 9.
  • a hydraulic jacking system 170' for moveably coupling sub-structure 150 to one column 140 is shown.
  • system 170' can be used in place of system 170 previously described. More specifically, one system 170' is provided between each column 140 and sub-structure 150, which supports deck 160 (not shown).
  • Each jacking system 170' includes a plurality of uniformly axially spaced support members 17 extending from the corresponding column 140 and an extendable hydraulic ram 172' coupled to sub-structure 150 opposite the vertical column of support members 171 '.
  • Each ram 172' has an upper end 172a' and a lower end 172b' that can be hydraulically moved vertically away from each other and toward each other.
  • Each end 172a', 172b' comprises a foot 173' sized to engage a mating support member 17 .
  • sub-structure 150 (and deck 160 disposed thereon) can be vertically raised along columns 140 in a step-wise manner by releasably coupling foot 173' disposed at lower end 172b' to one member 17 ( Figure 8A), extending hydraulic ram 172' and releasably coupling foot 173' disposed at upper end 172a' to one member 17 ( Figure 8B), and then disengaging foot 173' disposed at lower end 172b' from members 17 and contracting hydraulic ram 172' to lift foot 173'.
  • sub-structure 150 (and deck 160 thereon) can be controllably raised upward along columns 140; and by reversing the process shown in Figures 8A-8C, substructure 150 (and deck 160 thereon) can be controllably lowered along columns 140.
  • a strand jack system 170" for moveably coupling substructure 150 to one column 140 is shown.
  • system 170” can be used in place of system 170 previously described. More specifically, one system 170” is provided between each column 140 and sub-structure 150, which supports deck 160 (not shown).
  • Strand jack system 170” includes a winch 171 " mounted to the upper end 140a of the corresponding column 140 and a cable 172" extending from winch 171 " to sub-structure 150. The winch 171 " on columns 140 are operated in unison to raise and lower sub-structure 150 (and deck 160 thereon).
  • a locking mechanism is preferably provided between each column 140 and sub-structure 150 to releasably lock sub-structure 150 and deck 160 relative to the corresponding column 140 at the desired vertical position.
  • any suitable type of locking mechanism known in the art can be used.
  • deck 160 is seated directly on sub-structure 150, which supports deck 160 and moves deck 160 vertically up and down along columns 140.
  • deck 160 is not buoyant and is not adjustably buoyant.
  • deck 160 is sized such that it can be passed horizontally between each pair of adjacent columns 140 during integration.
  • deck 160 has a horizontal width Wi 6 o that is less than the minimum horizontal distance D 140 between each pair of adjacent columns 140.
  • deck 160 is square, and thus, each side of deck 160 has the same horizontal width Wi 6 o that is less than the minimum horizontal distance D 140 between each pair of adjacent columns 140.
  • sub-structure 150 and/or deck 160 preferably includes rigid column support structures extending around each column 140 to restrict and/or prevent columns 140 from deflecting outward.
  • Figure 10A illustrates an embodiment of a column support structure 190 disposed about each column 140.
  • column support structures 190 extend completely around columns 140 and are rigidly secured to deck 160 or sub-structure 150.
  • column support structures 190 are also disposed about each column 140 and are rigidly secured to deck 160 or sub-structure 150.
  • a deck extension 161 extends from each side of deck 160 between a pair of adjacent columns 140.
  • Deck extensions 161 are fixably coupled to the support structures 190 disposed about the corresponding columns 140.
  • deck extensions 161 are attached to deck 160 and support structures 190 after deck 160 is positioned atop sub-structure 150.
  • Crane 40 can be used to lift and position extensions 161, so that they can be attached to deck 160. It should be appreciated that deck extensions 161 effectively increase the operating area of deck 160 for equipment and personnel.
  • Support structures 190 are rigid and fixably secured to deck 160, and thus, restrict and/or prevent upper ends 140a of columns from deflecting outward (or inward) relative to each other.
  • support structures 190 can be installed with sub-structure 150 or installed after mounting deck 160 to sub-structure 150 as described in more detail below.
  • inclusion of support structures 190 increases the interfacing area with each column 140, and thus, enables the use of a plurality of jack-up assemblies 170 for each column 140. Namely, as shown in Figures 10A and 10B, four uniformly circumferentially-spaced jack-up assemblies 170 are provided between each column 140 and the corresponding support structure 190.
  • Column support structures 190 provide structural support, as well as foundations for mooring or riser systems.
  • FIGS 7A-7J an embodiment of a method for assembling platform 100 at dockside location 12 and subsequently deploying platform 100 is schematically illustrated.
  • Figures 7A-7D illustrate the construction of deck substructure 150 and integration of deck 160 to form platform 100 at dockside location 12
  • Figures 7E-7H illustrate the deployment of platform 100 from dockside location 12 to operating site 14
  • Figures 71 and 7 J illustrate the installation of platform 100 at operating site in a deep draft configuration.
  • hull 120 can be constructed in any suitable means known in the art.
  • hull 120 can be constructed at dockside location 12, constructed at another location and transported to dockside location 12, or constructed in parts at one or more locations, which are transported to dockside location 12 for assembly.
  • jack-up assemblies 170 (previously described and shown in Figure 4), sub-structure 150, and deck 160 are mated to hull 120.
  • sub-structure 150 is constructed in place and mounted to pinions 172, which engage toothed racks 171 secured to columns 140 (as previously described and shown in Figures 4 and 5).
  • sub-structure 150 is installed in place at vertical height H 171 as shown in Figure 7C, which correlates to the lowermost position 160b.
  • deck 160 is lifted by crane 40, passed between two columns 140, positioned directly over sub-structure 150, and then lowered onto sub-structure 150, thereby completing assembly of platform 100 at dockside location 12.
  • crane 40 only needs to lift deck 160 to lowermost position 160b, which is less than the maximum lifting height of crane 40, less than the height H 12 o> of hull 120 above waterline 13, and less than the height above the waterline 13 at which deck 160 can be positioned while ensuring stability of platform 100 at dockside location 12 with a maximum draft D120 that is less than the depth D w i2 of water 11 at dockside location 12 (typically about 30-40 ft.). In some embodiments, with a draft D120 of about 30-40 ft., the height above the waterline 13 at which deck 160 can be positioned while ensuring stability is about 120 ft. Due to the weight of deck 160, the draft D120 of hull 120 may increase, however, hull 120 can be controllably deballasted to ensure draft D120 is less than the depth D w i 2 of water 1 1 at dockside location 12.
  • the assembled platform 100 is floated from dockside location 12 to a nearshore location 15.
  • Deck 160 is maintained at the lowermost position 160b, to maintain a relatively low center of gravity for platform 100, thereby ensuring dynamic stability of platform 100 as it is floated to nearshore location 15.
  • Water 11 has a depth D wl5 at nearshore location 15 that is substantially greater than the water depth D w i2 at dockside location 12. Therefore, as desired (e.g., to further enhance the dynamic stability of platform 100 prior to being floated from nearshore location 15 to operating site 14), hull 120 is ballasted at nearshore location 15 to increase the draft D120 as shown in Figure 7F.
  • Deck 160 can be raised as hull 120 is ballasted to ensure the desired height of deck 160 above the waterline 13.
  • the draft D120 of hull 120 is preferably not increased to the full deep draft D120 of hull 120 at nearshore location 15 in order to minimize drag and loads experienced by platform 100 as it is floated from nearshore location 15 to operating site 14.
  • Deck 160 can be raised with jack-up assemblies 170 and sub-structure 150 as necessary to ensure deck 160 is at the desired height above the waterline 13 as draft D120 is increased. As shown in Figures 7G and 7H, with draft D120 increased at nearshore location 15 to enhance stability, platform 100 is floated from nearshore location 15 to operating site 14.
  • hull 120 is ballasted to increase the draft D120 of hull 120 to the desired deep draft D 120 .
  • the water 1 1 at offshore location 14 has a depth D w i 4 that is substantially greater than the water depth D w i5 at nearshore location 15 and provides no limitation on the draft D120 of hull 120.
  • hull 120 is ballasted to a draft D120 of greater than 150 ft. at the operating site.
  • deck 160 is raised with jack-up assemblies 170 and sub-structure 150 to the desired height above waterline 13 as hull 120 is ballasted.
  • mooring system 180 is installed as shown in Figure 7 J, thereby completing the deployment and installation of platform 100.
  • embodiments of semi-submersible platforms described herein can be fully assembled and constructed at a dockside location (e.g., dockside location 12) with a limited water depth (e.g., depth D wl2 ).
  • a dockside location e.g., dockside location 12
  • a limited water depth e.g., depth D wl2
  • Such embodiments allow for construction at dockside locations having water depths that limit installation heights of decks (e.g., 30-40 ft. water depths) with dynamic stability while enabling a deep draft installation at the operating site (e.g., draft D120 greater than 150 ft. at the operating site 14).
  • the deep draft capability of embodiments described herein offers the potential for reduced vertical and rotational motions of the deployed platform (e.g., less than 10-15 ft. heave) which make it suitable for use with top tensioned risers and dry production trees. It should be appreciated that the use of top tensioned risers in drilling and production systems allows direct access into subsea reservoirs from the platform deck and offer significant economic advantage to oil and gas production.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Ocean & Marine Engineering (AREA)
  • Structural Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Civil Engineering (AREA)
  • Architecture (AREA)
  • Transportation (AREA)
  • Earth Drilling (AREA)

Abstract

La présente invention concerne une plateforme semi-submersible pour des opérations en mer, comprenant une coque flottante présentant une base à flottabilité réglable et une pluralité de colonnes à flottabilité réglable s'étendant verticalement à partir de la base. En outre, la plateforme comprend un pont accouplé de manière mobile aux colonnes. Le pont est configuré pour se déplacer verticalement vers le haut et vers le bas par rapport à la coque.
PCT/US2015/044861 2015-01-12 2015-08-12 Plateformes en mer semi-submersibles à fort tirant d'eau flottantes et procédés d'assemblage et de déploiement de celles-ci WO2016114820A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201562102278P 2015-01-12 2015-01-12
US62/102,278 2015-01-12

Publications (1)

Publication Number Publication Date
WO2016114820A1 true WO2016114820A1 (fr) 2016-07-21

Family

ID=54007992

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2015/044861 WO2016114820A1 (fr) 2015-01-12 2015-08-12 Plateformes en mer semi-submersibles à fort tirant d'eau flottantes et procédés d'assemblage et de déploiement de celles-ci

Country Status (2)

Country Link
US (1) US20160201285A1 (fr)
WO (1) WO2016114820A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111907654A (zh) * 2020-08-18 2020-11-10 上海交通大学 Tlp浮式风机与养殖网箱的集成开发平台
CN113802535A (zh) * 2021-08-27 2021-12-17 中经建研设计有限公司 一种海上多功能勘探平台
CN113998063B (zh) * 2021-11-24 2022-11-11 上海雄程海洋工程股份有限公司 海洋坐底式安装平台的浮力调节方法
CN114368456B (zh) * 2021-12-15 2023-04-18 上海振华重工启东海洋工程股份有限公司 一种海上平台的上下浮体分离工艺

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1296910A (fr) * 1969-07-07 1972-11-22
JPS57130888A (en) * 1981-02-07 1982-08-13 Mitsui Eng & Shipbuild Co Ltd Semi-submerged work ship associated with elevating work table
JPS57155188A (en) * 1981-03-19 1982-09-25 Hitachi Zosen Corp Construction method for half submergible type working ship
US6374764B1 (en) * 1998-11-06 2002-04-23 Exxonmobil Upstream Research Company Deck installation system for offshore structures
US20060086305A1 (en) * 2003-10-07 2006-04-27 Deepwater Technology Group Pte Ltd. Extended semi-submersible vessel (ESEMI)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1366164A (fr) * 1963-05-29 1964-07-10 Nouvelles plate-formes marines de forage et de production
FR2772336B1 (fr) * 1997-12-12 2000-01-14 Doris Engineering Plate-forme semi-submersible d'exploitation d'un champ petrolier en mer et procede d'installation d'une telle plate-forme
US6718901B1 (en) * 2002-11-12 2004-04-13 Technip France Offshore deployment of extendable draft platforms
US6935810B2 (en) * 2003-06-11 2005-08-30 Deepwater Technologies, Inc. Semi-submersible multicolumn floating offshore platform
US7467912B2 (en) * 2004-09-30 2008-12-23 Technip France Extendable draft platform with buoyancy column strakes
US8430050B2 (en) * 2011-02-24 2013-04-30 Technip France System and method for deck-to-column connection for extendable draft offshore platforms
US20160040383A1 (en) * 2014-08-07 2016-02-11 Chevron U.S.A. Inc. Floating system integration methodology

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1296910A (fr) * 1969-07-07 1972-11-22
JPS57130888A (en) * 1981-02-07 1982-08-13 Mitsui Eng & Shipbuild Co Ltd Semi-submerged work ship associated with elevating work table
JPS57155188A (en) * 1981-03-19 1982-09-25 Hitachi Zosen Corp Construction method for half submergible type working ship
US6374764B1 (en) * 1998-11-06 2002-04-23 Exxonmobil Upstream Research Company Deck installation system for offshore structures
US20060086305A1 (en) * 2003-10-07 2006-04-27 Deepwater Technology Group Pte Ltd. Extended semi-submersible vessel (ESEMI)

Also Published As

Publication number Publication date
US20160201285A1 (en) 2016-07-14

Similar Documents

Publication Publication Date Title
US6666624B2 (en) Floating, modular deepwater platform and method of deployment
US7219615B2 (en) Extended semi-submersible vessel (ESEMI)
US7934462B2 (en) Offshore floating structure with motion dampers
EP2726362B1 (fr) Plateforme en mer à colonnes à déport externe
AU701557B2 (en) Offshore apparatus and method for oil operations
EP1766143B1 (fr) Plate-forme de forage en mer de ballastage equipee d'une bouee
US8616806B2 (en) Riser support system for use with an offshore platform
US8707882B2 (en) Offshore platform with outset columns
US5330293A (en) Floating production and storage facility
US7854570B2 (en) Pontoonless tension leg platform
AU2005226752B2 (en) Single column extendable draft offshore platform
AU2013281122B2 (en) Floating offshore platform and centralized open keel plate
US20160201285A1 (en) Floating Deep Draft Semi-Submersible Offshore Platforms and Methods for Assembling and Deploying Same
AU4084700A (en) Method and apparatus for deck installation on an offshore substructure
US20170129571A1 (en) Tapered Column Deep Draft Semi-Submersible (TCDD-SEMI)
EP3810500B1 (fr) Procédé et navire pour déployer des objets lourds
OA16697A (fr)

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15754356

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15754356

Country of ref document: EP

Kind code of ref document: A1