JP3749480B2 - Extension base type tension leg platform foundation structure - Google Patents

Description

[0001]
1. TECHNICAL FIELD OF THE INVENTION
The present invention relates to a foundation structure for a small expansion base type tension leg platform for supporting an offshore platform. (The tension leg platform may be referred to as a TLP.) The device of the present invention comprises a plurality of support columns arranged around an open area provided around the central axis of the foundation structure and a plurality of connections. Comprising a pontoon and a plurality of stabilizing wings or arms for removably securing a plurality of tendons secured to the seabed, wherein the column is preferably arranged symmetrically about the central axis .
[0002]
In particular, the present invention relates to a small, extension-based tension leg platform foundation structure for supporting the platform, the platform being wave permeable provided about the central axis of the foundation structure. Having a plurality of support columns arranged around an open area, wherein adjacent columns are connected to each other by at least one pontoon, the columns being preferably symmetrical about a central axis Placed in. The foundation structure also has a plurality of stabilizing wings or arms extending outwardly from the column and / or pontoon, each wing designed to removably secure at least one tendon secured to the seabed. ing. Each column has an upper surface portion and a submerged portion. The foundation structure device reduces bending fatigue of tendons that secure the foundation structure to the sea floor by minimizing, or at least reducing, translational motion and rotational bending. This device also decouples the tendon space from the column space. The present invention also relates to a platform employing this foundation structure, a method for constructing this structure, a method for securing an offshore platform, a method for reducing fatigue of the tendon to be secured and a connecting portion, and extending their useful lives.
[0003]
2. Explanation of related technology
A number of foundation structures are disclosed in prior art documents. Many of these foundation structures are so-called large-scale support structures that are anchored to the sea floor using a tendon array. These tendons form a pattern that defines the boundaries of a relatively large area of the seabed. Small foundation structures are known to those skilled in the art, but they employ one central column with radially arranged arms. U.S. Pat. Nos. 3,982,492, 4,421,436, 4,793,738, 4,913,233, which are integrated into this large and small platform, 4,938,632, 4,983,073, 5,147,148, 5,381,865, 5,421,676, 5,431,511, fifth , 433,273, 5,549,164, 5,507,598, 5,567,086, 5,669,735, and 5,775,846. Yes. However, these structures do not have the features of the present invention. For example, these structures include a series of arms or wings extending radially outward from a wave permeable foundation structure having a plurality of columns that minimizes or at least reduces material fatigue of the fastening tendons. I do not have. Thus, minimizing and wave-transmitting with multiple columns, minimizing or at least reducing tendon material fatigue and having a fixed pattern on the seabed similar to the foundation structure of large tension leg platforms There is a request for a foundation structure.
[0004]
(Summary of the Invention)
The present invention provides a base structure for an extension base type tension leg platform that is compact, has multiple columns, and is wave permeable in the center to support an offshore platform. The apparatus of the present invention comprises a plurality of support columns arranged around an open area provided around the central axis of the foundation structure and at least one floating pontoon connecting adjacent columns to each other. These columns are then designed to engage and support the platform, and the columns are preferably arranged symmetrically around the central axis. In operation, each column has a submerged portion and a non-submerged portion, and preferably the floatability of each column can be selectively adjusted by ballast control along the submerged floating pontoon. The foundation structure also has at least one wing or arm that can be removably attached to or integral with each column or pontoon. Each wing or arm is secured to at least one tendon secured to the seabed. Each wing may be a closed structure, an open structure, or a composite structure (open and closed parts), where the closed wings can be individually ballasted. .
[0005]
The present invention provides a small TLP foundation structure for supporting an offshore platform, which platform forms an open area with wave transmission provided around the central axis of the foundation structure. A plurality of supporting columns. At this time, adjacent columns are connected to each other by a plurality of pontoons, and the columns are preferably arranged symmetrically around the central axis. The foundation structure also has a plurality of wings or arms extending radially outward from the column and / or pontoon, each wing designed to removably secure at least two tendons secured to the seabed. ing. Each tendon engages an opposing horizontal side of the wing or arm. Each column has an upper surface portion and a submerged portion. Preferably, the floatability of each column can be selectively adjusted by performing ballast control along the submerged floating pontoon. The foundation structure reduces the bending fatigue of the tendon that secures the foundation structure to the sea floor by reducing translational movement and rotational bending, and the bending fatigue at the connection that secures the tendon to the wing In addition, the horizontal separation of the tendon pouch from the upper deck dimensions is cut off. This foundation structure is similarly designed to provide a moon pool sufficient to accommodate a conventional top suspended vertical conduit and direct access to the oil well.
[0006]
The present invention also provides a workplace platform and equipment platform supported by the foundation structure of the present invention. As described above, the base structure includes a platform that is detachably attached to the base structure, the base structure, and a tendon fixed to the seabed. The platform includes a drilling rig, an oil well finishing device, a vertical conduit extending upwardly through the open area of the foundation structure extending from the sea well to the platform, and other well-related devices.
[0007]
The present invention also provides a method for supporting and securing an offshore platform so as to reduce material fatigue when attaching tendons and connections. The method comprises the steps of supporting the offshore platform on the foundation structure of the present invention and the foundation structure such that a portion of the column of the foundation structure is above the water surface and a portion of the column is below the water surface. Adjusting the ballast of the object, and arranging the plurality of tendons so as to be fixed to the seabed at one end of the plurality of tendons and fixed to the wing on the foundation structure at the other end.
[0008]
The invention further provides a method for forming a foundation structure according to the invention, the method comprising connecting adjacent support columns with at least one submersible pontoon, and at least one wing. Are attached to each column or pontoon, and the tendon is secured to the wing at one end and secured to the seabed anchor at the other end.
[0009]
(Detailed Description of the Invention)
A small support foundation structure for TLP can be constructed that employs a tendon support pattern having a geometry similar to that of a larger or full standard support structure. The foundation structure is provided with a plurality of three or more floating support columns which are wave-transmitting in an opening inner region provided around the central axis and are arranged around the central axis. At this time, the columns are preferably arranged symmetrically around the central axis. Adjacent columns are connected by at least one floating pontoon. The column or pontoon has radially extending floating wings or arms. Each wing has means for securing at least one tendon tethered to the seabed. These wings help stabilize the small foundation structure, improve the hull weight effect compared to conventional TLP, minimize the column or pontoon, and the waves and currents loading the hull, Improves the fatigue life of tendons, improves the fatigue life of the connectors at the top and bottom of the tendons, increases flexibility in component design, and provides horizontal separation of tendon pouches from top deck dimensions Detach, reduce the natural cycle swell, pitch, or roll of the platform, and relax the ballast conditions to keep the tendon tension uniform. By optimizing the column space, it helps to reduce the steel weight of the deck structure and stabilizes the loading and transporting of the hull. The arrangement of the present invention also provides a moon pool sufficient to accommodate conventional top-lift vertical conduits and direct access to oil wells. According to this structure, the ratio of the subsurface column capacity to the pontoon capacity can be optimized so as to improve the hydrodynamic canceling effect. Pre-configured structures can provide a stable platform for later deck mounting and deck formation.
[0010]
The present invention generally includes a small support foundation structure having at least three support columns disposed about a central axis, preferably the columns are symmetrical about the central axis. Be placed. This foundation structure is designed to support the offshore platform. In a preferred embodiment, the present invention provides a plurality of submergible floating pontoons, at least one pontoon connecting each pair of adjacent columns at each submerged location on each column, each column and / or each pontoon. And a plurality of wings extending radially outward. Each wing is secured to at least one tendon connection. Preferably, the wings are arranged symmetrically around the central axis of the structure.
[0011]
The present invention generally relates to a method of tethering offshore platforms, the method comprising fixing a plurality of tendons on the seabed at one end and a plurality of tendons at the other end. Securing to the wings attached to the base and attaching the platform to the top of the plurality of floating columns of the foundation structure, these columns being connected by a plurality of floating pontoons.
[0012]
The present invention generally relates to a method for improving the material fatigue life of submarine tendons, which typically includes steps for forming a floating column and for forming a controllable floating foundation structure. Connecting a plurality of columns using a plurality of horizontally arranged floating pontoons, attaching a plurality of arms having proximal and distal ends around an outer periphery of the foundation structure, and each arm And fixing the other end of the tendon to the seabed.
[0013]
The wing or arm is designed to improve the overall stability of the foundation structure so as to reduce the movement of the foundation structure and the fixed tendons against the sea floor due to the action of waves, tidal currents and the atmosphere . As movements (translational and rotational movements, swells, pitches, and rolls) are reduced, movements to tendons and to both the submarine and foundation structure tendon connectors are reduced. In this way, bending fatigue due to relative movement of the foundation structure with respect to the sea floor is reduced, and the service life of the tendon and the connecting portion is improved.
[0014]
In general, the wing increases the radial extension of the foundation structure by about 10% to about 100%, and the term radial extension of the foundation structure is generally determined from the central axis of the foundation structure, which is usually determined by the pontoon. It means the distance to a predetermined point on the outer periphery of the structure. That is, if the wing is secured to the column, the wing increases the distance from the central axis to the outer surface of the column between about 10% and about 100%. Preferably, the wing increases between about 10% to about 70% of the foundation structure, especially between about 25% to about 75%, but less and greater radial extension is realized as well. Is done.
[0015]
The column has a larger diameter or dimension than the pontoon or wing. However, these three components may have similar dimensions. In addition, the exact shape of the columns, pontoons, and wings is a matter of design criteria and choice. Any regular or irregular geometric shape is acceptable, including but not limited to circular, square, rectangular, elliptical, triangular, pentagonal or other polygonal sections Etc. are included. Preferably, it has either a circular cross section, a square cross section, a cross section with 5 sides, or a polygonal cross section. The pontoon preferably has a circular cross section, a square cross section, a rectangular cross section, or a polygonal cross section.
[0016]
The foundation structure of this invention is comprised so that it may have the column arrange | positioned symmetrically around the center axis | shaft of a foundation structure. However, asymmetrically arranged columns are also included in the scope of the present invention. An asymmetric configuration can be regularly repetitive or less responsive to periodic forces. In general, the foundation structure has at least three columns. Suitable foundation structures have three or four columns. For a three-column foundation structure, the columns are arranged around a central axis so as to form a triangle. Preferably, the triangle is an equilateral triangle, but other triangles are equally conceivable, such as an isosceles triangle, a right triangle, or a general triangle. For four or more foundation structures, the columns are arranged in a polygonal shape around the center axis of the foundation structure. For a four-column foundation structure, the polygonal shape is preferably symmetric, such as a square, rectangle, or parallelogram, but as with a trapezoid or a quadrilateral with four different interior angles, A quadrilateral polygon or quadrilateral is also conceivable. For a foundation structure having more columns, the columns are arranged in a polygonal shape around the central axis of the foundation structure. Furthermore, closed polygonal shapes are preferred, but open polygonal shapes are also conceivable. In an open polygonal shape, one connecting pontoon can be omitted and the interior of the foundation structure can be accessed on a large scale.
[0017]
The wing may be a closed structure, an open structure, or a composite structure of an open part and a closed part. The closed structure may have buoyancy so that individual ballast adjustments can be made. The open wing is a truss structure or a beam structure having a reinforcing cross member. The closed wing may have a welded or continuous structure so that it can be completely or partially flooded.
[0018]
The foundation structure of the present invention has associated ballast pumps to adjust the ballast of components, such as columns, pontoons, and / or wings, or the entire foundation structure, either globally or individually. Ballast adjustment facilitates the adjustment of tendon tension and allows assembly, platform attachment, and / or smooth replacement.
[0019]
The platform connector and tendon connector and the tendon connection between the base structure and the platform or tendon may be, but are not limited to, any form of connector or connection widely used by those skilled in the art. However, the connector can be welded, any form of welded connection, or any type of fixed connection.
[0020]
Placing the tendon connector is a design criterion or choice. Generally, the tendon connector is located at or near the outer or distal end of the wing. Preferably, the connector is located on the end of each wing, on the side of each wing, or at or near the end of each wing. Each wing can have one or more connectors and associated tendons, but preferably has two or more connectors, and it is particularly preferred to provide two connectors for each wing. .
[0021]
Suitable materials for forming the foundation structure and components include, but are not limited to, metals such as iron or steel, alloys such as stainless steel, ceramics, plastics, concrete, aggregates (aggregates) ), Composite materials, or other structural building materials.
[0022]
(Base structure according to a preferred embodiment of the present invention)
3 column base structure
Referring now to FIGS. 1A and 1B, a small TLP support foundation structure according to a preferred embodiment is generally designated 100 and includes three cylindrical columns 102 arranged in a substantially vertical direction, The column includes a top end 104 designed to engage and support a platform (not shown). These columns 102 are arranged symmetrically around a central axis 106 and form an open central region 108 for easy access to the oil well conduit. At this time, the open area 108 is designed to be accessible to the submarine structure. In one preferred embodiment, the open area 108 is sufficient to accommodate a conventional upper suspended vertical conduit and other devices well known to those skilled in the art (in the middle of a deep sea drilling vessel). Shaft). The spacing of the columns 102 facilitates the passage of waves through the foundation structure 100 and improves the response of the foundation structure to waves, tidal currents, and wind movements.
[0023]
  The foundation structure 100 has at least one pontoon 110 arranged at a bottom portion 112 of adjacent columns 102 that connects them to each other in a substantially horizontal direction. Although the pontoon 110 is shown as connecting the bottoms 112 of the columns 102 to each other, the pontoon 110 can be placed anywhere along the column 102. The foundation structure 100 isExtend radially outward from each corner of the pontoon 110Having at least one wing.The wing 114 has a peripheral portion including a plurality of vertical side surfaces 116 and end surfaces. The vertical side 116 includes a pair of opposing horizontal surfaces 116 and ends that connect them at the radial tip.
  Each connector 118 is designed so that one end of the tendon is detachably fixed and the other end is fixed to the seabed.The connector 118 may be secured to one or both of the opposing horizontal surfaces 116 or may be secured to the end connecting the horizontal surfaces 116.
  Wing reduces the connection fatigue between tendons by increasing the distance between tendons. Improving the translational and rotational movement, swell, pitch, roll, or left / right swing of the TLP foundation structure correspondingly improves the fatigue life of the tendon and tendon connectors. These tendons are pulled evenly and adjusted independently for each column 102 and each pontoon 110 so that the translational and rotational movement of the fixed platform is minimized or at least reduced. Put ballast as possible.
[0024]
Referring now to FIGS. 1C and 1D, a foundation structure according to another preferred embodiment includes three columns of substantially square cross-section with outwardly facing sides 120. A wing 114 extends from this side, and a trapezoidal pontoon 110 connects the columns 102 together. Wing 114 has any other design, but has a trapezoidal proximity 122 and a rectangular end 124. The connector 118 has any other design but has a trapezoidal sturdy body 126 and a circular connector 128 into which the tendon end is inserted.
[0025]
The column 102 shown in FIGS. 1A-1D is oriented substantially vertically, but may be inclined with respect to the vertical axis as shown in FIGS. 1E and 1F. In the configuration in which the column is inclined, the column dimension d at the upper part 130 of the foundation structure 100 is preferably used.₁Is the column dimension d at the upper part 130 of the foundation structure 100₂The column 102 is inclined so as to be smaller than that. In general, the angle φ formed between the axis 134 of the column and the vertical axis 136 of the foundation structure is between 90 ° (vertical) and about 45 °, preferably between about 85 ° and about 50 °. In particular between about 80 ° and about 60 °.
[0026]
Referring also to FIGS. 1G and 1H, a foundation structure 100 according to another embodiment is illustrated, where there is no pontoon connecting two of these columns 102. In such a configuration, the open area 108 can be accessed directly from the side inlet 138, ie, the inlet 138 corresponds to the location of the omitted connecting pontoon.
[0027]
4-column base structure
Referring now to FIGS. 2A and 2B, a small TLP foundation structure according to another preferred embodiment is indicated generally by the numeral 200. This foundation structure has four columns 202 having a square cross section, elongated and extending substantially vertically. The column has an upper end 204 designed to support a platform (not shown). These columns 202 are arranged symmetrically around a central axis 206 and form an open central region 208 for easy access to the oil well conduit. At this time, the open area 208 preferably has a size of a moon pool sufficient to accommodate a conventional top suspended vertical conduit and other devices well known to those skilled in the art. The separation of the columns 202 improves the wave permeability to the foundation structure 200 and further improves the response of the foundation structure to waves, tidal currents and wind movements.
[0028]
The foundation structure 200 has at least one pontoon 210 arranged at a bottom portion 212 of an adjacent column 202 that connects them to each other in a substantially horizontal direction. The base structure 200 further includes at least one wing 214 extending radially from each column 202. Each wing 214 has a top surface 216 and a bottom surface 218 for engaging a corner or apex 220 away from the center of the column 202. Each wing 214 similarly has a tendon connector 224 secured to the opposite side 222. Each tendon connector 224 is designed to detachably fix one end of a tendon (not shown) and fix the other end to the seabed. Wing reduces the connection fatigue between tendons by increasing the distance between tendons. Improving the translational and rotational movement, swell, pitch, roll, or left / right swing of the TLP foundation structure correspondingly improves the fatigue life of the tendon and tendon connectors. These tendons are pulled evenly and adjusted independently for each column 202 and each pontoon 210 so that the translational and rotational movement of the fixed platform is minimized or at least reduced. Put ballast as possible.
[0029]
Referring now to FIGS. 2C and 2D, a foundation structure according to another preferred embodiment is illustrated, which is substantially square, elongated, and substantially vertically arranged with four columns 202. These columns 202 are rotated 45 ° with respect to the columns shown in FIGS. 2A and 2B. In such a configuration, the wing 214 extends from the outwardly facing side 226 rather than the apex 220 of each column 202 as in the embodiment shown in FIGS. 2A and 2B. The wing 214 of the embodiment shown in FIGS. 2C and 2D is a composite structure having a trapezoidal proximity 228 and a rectangular end 230. Similarly, the connector 224 is illustrated in another configuration with a quadrilateral body 232 that includes a circular connector 234 into which the tendon end is inserted.
[0030]
Another configuration of the wing is shown in FIG. 2E, where the wing 416 has two components: a substantially rectangular proximate portion 236 and a trapezoidal end 238. The connector 220 is fixed to the laterally facing side 240 of the trapezoidal end 224, and thus the connector 220 is disposed on the outer end 242 of each wing 214 of the base structure 200. Of course, the trapezoidal end 238 may have a square or rectangular shape as well.
[0031]
Referring now to FIGS. 3A and 3B, a small TLP foundation structure according to another preferred embodiment is indicated generally at 300. The base structure 300 includes four columns 302 that are pentagonal, elongated, and substantially vertically extended. This column has an upper end 304 designed to support a platform (not shown). These support columns 302 are symmetrically disposed about a central axis 306 and form an open central region 308 for easy access to the oil well conduit. At this time, the open area 308 preferably has a size of a moon pool sufficient to accommodate a conventional top suspended vertical conduit and other devices well known to those skilled in the art. Each column 302 has one side 310 that faces generally outward relative to the shaft 306 to facilitate securing the wing 316. The separation of the columns 302 improves the wave permeability to the foundation structure 300 and further improves the response of the foundation structure to waves, tidal currents, and wind movements.
[0032]
The foundation structure 300 has at least one pontoon 312 disposed at a bottom 314 of an adjacent column 302 that connects them to each other in a substantially horizontal direction. The base structure 300 further includes at least one wing 316 extending radially from the side surface 310 facing the outside of each column 302. Each wing 316 has a tendon connector 320 secured to an opposing horizontal side 318. Each tendon connector 320 is designed so that one end of a tendon (not shown) is detachably fixed and the other end is fixed to the seabed. Wing reduces the connection fatigue between tendons by increasing the distance between tendons. Improving the translational and rotational movement, swell, pitch, roll, or left / right swing of the TLP foundation structure correspondingly improves the fatigue life of the tendon and tendon connectors. These tendons are pulled evenly and adjusted independently for each column 302 and each pontoon 312 so that the translational and rotational movement of the fixed platform is minimized or at least reduced. Put ballast as possible.
[0033]
Referring now to FIGS. 4A and 4B, a small TLP foundation structure according to another preferred embodiment is indicated generally by the numeral 400. The foundation structure 400 includes four columns 402 that are substantially square, elongated, and extend in a substantially vertical direction. This column has an upper end 404 designed to support a platform (not shown). These support columns 402 are arranged symmetrically around a central axis 406 and form an open central region 408 for easy access to the oil well conduit or the seabed to be secured. At this time, the open area 408 has a size of a moon pool sufficient to accommodate conventional top suspended vertical conduits and other devices well known to those skilled in the art. Each column 402 has one side 410, usually facing outward with respect to the axis 406, to help secure the wing 416. The separation of the columns 402 improves the wave permeability to the foundation structure 400 and further improves the response of the foundation structure to waves, tidal currents, and wind movements.
[0034]
The foundation structure 400 has at least one pontoon 412 connecting them to each other at a position above the bottom 403 of the adjacent column 402. The base structure 400 further includes at least one wing 416 extending radially from the side surface 410 facing the outside of each column 402. Each wing 416 has a tendon connector 420 secured to a laterally facing side 410. Each tendon connector 420 is designed so that one end of a tendon (not shown) is detachably fixed and the other end is fixed to the seabed. In this preferred embodiment, these wings 416 are open truss structures or beam structures including outward beams 422 and cross beams 424.
[0035]
Wing reduces the connection fatigue between tendons by increasing the distance between tendons. Improving the translational and rotational movement, swell, pitch, roll, or left / right swing of the TLP foundation structure correspondingly improves the fatigue life of the tendon and tendon connectors. These tendons are pulled evenly and adjusted independently to each column 402 and each pontoon 412 so that the translational and rotational movement of the fixed platform is minimized or at least reduced. Put ballast as possible.
[0036]
Of course, the columns of the embodiment shown in FIGS. 2A-2D, 3A and 3B, and further in FIGS. 4A and 4B can be tilted like the columns shown in FIGS. 1C and 1D. Further, all embodiments shown in these drawings may utilize any design of wings and connectors, either independently or in any combination. Furthermore, in any suitable embodiment, the inlet to the open area can be constructed by removing the connection pontoon between the pair of columns.
[0037]
Although the preferred embodiment has disclosed three and four column structures, as will be appreciated by those skilled in the art, the number and shape of columns and pontoons is a matter of design convenience and design criteria. Thus, the scope of the present invention is not limited. That is, a foundation structure having three or more columns is likewise an acceptable design.
[0038]
(Platform supported by a foundation structure according to a preferred embodiment of the present invention)
Referring now to FIG. 5, there is illustrated an expansion base type tension leg platform, generally designated 500, in accordance with a preferred embodiment of the present invention, which is a small platform support platform, generally designated 550. Supported by a structure. The platform 500 has a substantially flat upper deck 502 that is supported on the sub-deck 504 by an upper deck support 506. The sub deck 504 is supported by a sub deck support 508 that extends downward and is connected to a platform support 510 that extends substantially vertically.
[0039]
The foundation structure 550 has three cylindrical support columns 552 that include platform connectors 554 that are above the water surface line 557 and above the portion of the support column 552 that is above or above the water surface. Placed in. Platform connector 554 removably engages with distal end 512 of platform support 510. These columns 552 are arranged symmetrically around the central axis, as shown in FIG. 1A, and form an open central region 558 for easy access to the oil well conduit. At this time, the open region 558 preferably has a moon pool size sufficient to accommodate a conventional top suspended vertical conduit and other associated devices. By arranging the columns 552 apart, the wave permeability to the base structure 550 is improved.
[0040]
This foundation structure 550 has at least one floating pontoon 560 connecting them together in the lower or submerged portion 562 of the adjacent column 552. The foundation structure 550 also has at least one wing 564 extending radially from each column 552. Each wing 564 has a tendon connector 568 secured to the opposite horizontal side surface 566. Each connector 568 is designed to detachably engage with a tendon (not shown) fixed to the seabed. The wing 564 is designed to increase the distance between tendons to reduce the joint fatigue between tendons and the translational and rotational movement, swell, pitch, roll, or left and right swings of the platform. Yes. These tendons are pulled evenly and adjusted independently to each column 552 and each pontoon 560 so that the translational and rotational movement of the fixed platform is minimized or at least reduced. Put ballast as possible.
[0041]
Referring now to FIG. 6, there is illustrated an expansion-based tension leg platform, generally designated 600, according to another preferred embodiment of the present invention, which is a small platform, generally designated 650. Supported by a supporting foundation structure. The platform 600 has an oil well derrick 602 supported on a deck support structure 604. The deck support structure 604 has an upper deck 606 that is substantially flat, and the upper deck is supported on the sub deck 608 by the upper deck support 610. The sub deck 604 is supported by a sub deck support portion 612 that extends downward and connects to a platform support portion 614 in a substantially vertical direction.
[0042]
The foundation structure 650 has four support columns 652 including a platform connection 654, and the platform connection 654 is disposed on a portion of the support column 652 above or above the water surface. The platform connection portion 654 is detachably engaged with the platform support portion 614. These columns 652 are symmetrically arranged about the central axis as shown in FIG. 2C and form an open central region 658 for easy access to the oil well conduit. At this time, the open area 658 preferably has a moon pool size sufficient to accommodate a conventional top suspended vertical conduit and other associated devices. By arranging the columns 652 apart from each other, the wave permeability to the foundation structure 650 is improved.
[0043]
The foundation structure 650 has at least one floating pontoon 660 connecting them to each other at the bottom or subsurface portion 662 of the adjacent column 652. In addition, the base structure 650 further includes at least one wing 664 extending radially from a side surface facing the outside of each column 652. Each wing 664 has a tendon connector 668 secured to the opposite horizontal side 666. Each connector 668 is designed to detachably engage with a tendon (not shown) fixed to the seabed. Wing 664 increases the distance between tendons, reduces the connection fatigue between tendons, and reduces translational and rotational movement, undulation, pitch, roll, or left / right swing relative to tendons and connectors . These tendons are pulled evenly and adjusted independently to each column 652 and each pontoon 660 so that the translational and rotational movement of the fixed platform is minimized or at least reduced. Put ballast as possible.
[0044]
Referring now to FIG. 7, there is illustrated an expansion base type tension leg platform, generally designated 700, according to another preferred embodiment, which is a small platform support platform generally designated 750. Supported by objects. The platform 700 has an oil well derrick 702 supported on a deck support structure 704. The deck support structure 704 has a substantially flat upper deck 706 that is supported on the sub deck 708 by an upper deck support 710. The sub deck 604 is supported by a sub deck support portion 712 that extends downward and connects to a platform support portion 714 in a substantially vertical direction.
[0045]
The foundation structure 750 has three support columns 752 including a platform connection 754, and the platform connection 754 is disposed on a portion of the support column 752 above or above the water surface. The platform connection portion 754 is detachably engaged with the platform support portion 714. These columns 752 are arranged symmetrically around the central axis, as shown in FIG. 1C, and form an open central region 758 for easy access to the oil well conduit. At this time, the open region 758 preferably has a size of a moon pool sufficient to accommodate a conventional top suspended vertical conduit and other related devices. By arranging the columns 752 apart from each other, the wave permeability to the foundation structure 750 is improved.
[0046]
The foundation structure 750 has at least one floating pontoon 760 connecting them to each other at the bottom or underwater portion 762 of the adjacent column 752. The base structure 750 further includes at least one wing 764 extending radially from the side surface facing the outside of each column 752. Each wing 764 has a tendon connector 768 secured to an opposing horizontal side 766. Each connector 768 is designed to detachably engage with a tendon (not shown) fixed to the seabed. Wing 764 increases the distance between tendons, reduces connection fatigue between tendons, and reduces translational and rotational movement, undulation, pitch, roll, or left and right swings for the tendons and connectors . These tendons are pulled evenly and adjusted independently to each column 752 and each pontoon 760 so that the translational and rotational movement of the fixed platform is minimized or at least reduced. Put ballast as possible.
[0047]
Although the present invention has been described above with reference to preferred embodiments, modifications may be made by those skilled in the art without departing from the scope and spirit of the invention as described above and claimed below after reading this specification. And variations can be realized.
[Brief description of the drawings]
FIG. 1A is a plan view of a support structure for an extension base tension leg platform according to a first preferred embodiment of the present invention.
FIG. 1B shows a schematic perspective view of the structure shown in FIG. 1A.
FIG. 1C is a plan view of a support structure for an expansion base tension leg platform according to another preferred embodiment of the present invention.
FIG. 1D is a side view of the structure shown in FIG. 1C.
FIG. 1E is a plan view of a support structure for an extension base tension leg platform according to another preferred embodiment of the present invention.
FIG. 1F is a side view of the structure shown in FIG. 1E.
FIG. 1G is a plan view of an extension base tension leg platform support structure according to another preferred embodiment of the present invention.
FIG. 1H is a side view of the structure shown in FIG. 1G.
FIG. 2A is a plan view of a support structure for an expansion base tension leg platform according to another preferred embodiment of the present invention.
FIG. 2B shows a schematic perspective view of the structure shown in FIG. 2A.
FIG. 2C is a plan view of a support structure for an expansion base tension leg platform according to another preferred embodiment of the present invention.
FIG. 2D is a side view of the structure shown in FIG. 2C.
FIG. 2E is a plan view of an alternative wing design.
FIG. 3A is a plan view of an extension base tension leg platform support structure according to another preferred embodiment of the present invention.
FIG. 3B shows a schematic perspective view of the structure shown in FIG. 3A.
FIG. 4A is a plan view of a support structure for an expansion base tension leg platform according to another preferred embodiment of the present invention.
FIG. 4B is a side view of the structure shown in FIG. 4A.
FIG. 5 shows a preferred embodiment of an offshore platform employing the expansion base tension leg platform support structure shown in FIG. 1;
FIG. 6 illustrates a preferred embodiment of an oil well derrick secured on an offshore platform employing the extended base tension leg platform support structure shown in FIG. 2C.
FIG. 7 illustrates a preferred embodiment of an oil well derrick secured on an offshore platform employing the expansion base tension leg platform support structure shown in FIG. 1C.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Small TLP support base structure, 102 ... Cylindrical column, 104 ... Top end, 106 ... Center axis, 108 ... Central area of opening, 110 ... Pontoon, 112 ... Bottom, 114 ... Wing, 116 ... Opposite side surface, 118 ... Tendon connector, 120... Side facing outward, 122... Proximity part, 124 ... Terminal part, 126 ... Body part, 128 ... Connector.

Claims (2)

Extension base type tension leg platform foundation structure for offshore platform,
At least three floating support columns arranged around the central axis to form an opening provided around the central axis of the foundation structure;
A plurality of floating pontoons spaced from the central axis and connecting at least some of these columns to each other, with one end of each pontoon connected to the bottom of one column and the other end A floating pontoon connected to the bottom of another column, where any two pontoons and the connection of one column form a corner;
A base structure having a plurality of tendon connectors fixed to the base structure,
Further comprising at least one wing having a peripheral edge extending radially outward from each corner and including a plurality of vertical sides and end faces;
Each tendon connector is fixed to the periphery of one wing,
A wing is a base structure characterized by being an open structure.
A foundation structure characterized by Extension base type tension leg platform foundation structure for offshore platform,
At least three floating support columns arranged around the central axis to form an opening provided around the central axis of the foundation structure;
A plurality of floating pontoons spaced from the central axis and connecting at least some of these columns to each other, with one end of each pontoon connected to the bottom of one column and the other end A floating pontoon connected to the bottom of another column, where any two pontoons and the connection of one column form a corner;
A base structure having a plurality of tendon connectors fixed to the base structure,
Further comprising at least one wing having a peripheral edge extending radially outward from each corner and including a plurality of vertical sides and end faces;
Each tendon connector is fixed to the periphery of one wing,
A wing is a composite structure of an open part and a closed part .

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