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WO2004033848A1 - Tube prolongateur et son procede d'installation - Google Patents

Tube prolongateur et son procede d'installation Download PDF

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Publication number
WO2004033848A1
WO2004033848A1 PCT/EP2003/010774 EP0310774W WO2004033848A1 WO 2004033848 A1 WO2004033848 A1 WO 2004033848A1 EP 0310774 W EP0310774 W EP 0310774W WO 2004033848 A1 WO2004033848 A1 WO 2004033848A1
Authority
WO
WIPO (PCT)
Prior art keywords
section
rigid pipe
buoyancy
riser
pipe section
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/EP2003/010774
Other languages
English (en)
Inventor
Terje Clausen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rockwater Ltd
Original Assignee
Rockwater Ltd
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
Priority claimed from GB0223619A external-priority patent/GB2393980B/en
Application filed by Rockwater Ltd filed Critical Rockwater Ltd
Priority to AU2003270284A priority Critical patent/AU2003270284A1/en
Publication of WO2004033848A1 publication Critical patent/WO2004033848A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/01—Risers
    • E21B17/015—Non-vertical risers, e.g. articulated or catenary-type
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B33/00—Sealing or packing boreholes or wells
    • E21B33/02—Surface sealing or packing
    • E21B33/03—Well heads; Setting-up thereof
    • E21B33/035—Well heads; Setting-up thereof specially adapted for underwater installations
    • E21B33/038—Connectors used on well heads, e.g. for connecting blow-out preventer and riser
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/01—Risers
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/01—Risers
    • E21B17/012—Risers with buoyancy elements
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B19/00—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables
    • E21B19/002—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling
    • E21B19/004—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling supporting a riser from a drilling or production platform

Definitions

  • the present invention concerns a riser, for the transport of fluid hydrocarbons from an underwater wellhead.
  • Risers of two different types are commonly used in bringing oil or gas from a sub-sea well to the surface.
  • Flexible pipes have the advantages of being relatively easy to install, reducing the cost and risks involved in the installation process itself, and being resistant to work fatigue brought on by cyclic forces exerted on the pipe by the movement of the sea and other factors.
  • solid steel pipes which are referred to as rigid, are considerably less costly to manufacture.
  • the first of these is the vertical riser, where the riser rises directly from the sub-sea well to a vessel on the surface of the sea.
  • the second is a catenary configuration in which the riser starts from the well head running along the seabed, before rising up from the seabed towards a vessel floating or otherwise situated on the sea's surface, such that the riser forms a gentle curve in the shape of a catenary, or the riser catenary extends directly from the well head itself to the support vessel.
  • FIG. 1 shows the use of flexible piping in a modification of the catenary configuration, as is known in the prior art.
  • a vessel 3 is disposed on the surface of the sea 1 , with a flexible riser 4, extending from the seabed up to the vessel in a configuration known as a "lazy S".
  • An anchored mid water arch 5 is provided over which the riser 4 passes so as to provide an upper catenary section and a lower catenary section.
  • FIG 2 shows an alternative configuration of a flexible riser known from the prior art, which is commonly referred to as a "lazy wave".
  • the flexible riser rises to the vessel 3 from the seabed 2 and is provided with a plurality of buoyancy elements 7 at a point along the flexible riser's length, such that a portion of the flexible riser is lifted up from the curve which the riser would otherwise adopt under its own weight as it rises from the seabed. A portion of the riser is thus retained substantially stationary in the water by the buoys, and is relatively unaffected by the movement in the vessel 3.
  • the buoyancy elements 7 generally consist of pre-formed foam discs, which are clamped around the flexible riser.
  • FIG 3 shows a rigid riser configuration.
  • Rigid risers are generally constructed from steel piping, in the form of tubular sections welded together. In the configuration shown in Fig 3, this is known as a steel catenary riser (SCR).
  • SCR steel catenary riser
  • This configuration comprises a continuous steel pipe, which may be several kilometres long rising to a vessel 3 on the sea surface from the seabed 2, bending in a smooth curve, such that the rigid riser leaves the wellhead in a substantially horizontal manner and arrives at the support vessel in a vertical or nearly vertical orientation.
  • this configuration has the drawback that variations in the position of the vessel 3 result in cyclic stresses at the touch down point 6 of the catenary riser 9, such that the rigid riser is fatigued over time, and is prone to failure.
  • the riser bar 12 remains substantially stationary in the water, regardless of movements in the surface vessel 3, such that the steel catenary riser 13 is isolated from cyclic effects, and the touch down zone 6 is not fatigued. Further, the load on the surface vessel from the risers is reduced, since the buoy carries the weight of the lower part of the risers. The cost and effort involved in installing and maintaining the system, in particular the anchoring of the float arrangements, is substantial however.
  • a riser having three sections. These three sections comprise an upper flexible riser section 10 ascending to the surface vessel 3, a second, lower, lower flexible riser section 15 ascending from the seabed, and a rigid riser section 14 disposed between and interconnecting the two flexible riser sections 10 and 15.
  • This configuration has the advantage that substantially all forces resulting from movement of the surface vessel 3 are absorbed by the two flexible portions of the riser s 10 and 15.
  • a further alternative arrangement is the tower riser, which comprises a rigid, vertical riser tower provided with air tanks at the upper extremity, and connected to a surface vessel by a flexible riser pipe.
  • the present invention seeks to overcome drawbacks of various riser configurations discussed above.
  • Objects of the present invention thus include the provision a riser configuration which is suitable for use in deep water, is less prone to fatigue effects or abrasion, and is of comparatively low cost and simple to construct and install.
  • a riser having a first, upper, rigid pipe section (6) and a second, lower, rigid pipe section (10), said second rigid pipe section further comprising a buoyancy section (16) at or in the region of an upper end thereof and said second rigid pipe section (13) forming a catenary in communication with the first, rigid pipe section and said first rigid pipe section forming a catenary between said buoyancy section and a point at or near the sea's surface.
  • the first, upper, rigid pipe section (6) meets said second, lower, rigid pipe section (10) at an angle exceeding 45 degrees.
  • a riser having a first, upper, rigid pipe section (6) and a second, lower, rigid pipe section (10), said second rigid pipe section further comprising a buoyancy section (16) at or in the region of an upper end of said second rigid pipe section (13), wherein said first rigid pipe section (6) meets said second rigid pipe section (10) at angle such that the first and second rigid pipe sections each assume respective catenary configurations when the riser is suspended in the sea.
  • the first, upper, rigid pipe section (6) is maintained in communication at said angle with said second, lower, rigid pipe section (10) by a connector.
  • the first, upper, rigid pipe section (6) is maintained in communication at said angle with said second, lower, rigid pipe section (10) by an articulated connector.
  • first, upper, rigid pipe section meets said, lower, rigid pipe section at an angle of substantially 90 degrees.
  • the buoyancy section comprises an elongate buoyancy element fitted around the riser.
  • the buoyancy section is tethered to a vessel on the sea's surface.
  • the buoyancy section is tethered to the seabed.
  • a further tether is provided between a point on said second, lower, rigid pipe section above the high bending area thereof, and the seabed.
  • at least one of said second, lower, rigid pipe section and said first, upper, rigid pipe section comprise a plurality of pipes.
  • the second, lower, rigid pipe section and said first, upper, rigid pipe sections each comprise a corresponding plurality of pipes.
  • the plurality of second, lower, rigid pipe sections pipes are arranged around the outside of said buoyancy section.
  • the plurality of second, lower, rigid pipe sections are spaced apart evenly about the circumference of said buoyancy section.
  • each of said plurality of second, lower, rigid pipe sections is fixed at or near an upper extremity thereof to said buoyancy section.
  • the buoyancy section is further provided with a plurality of sleeves intended to slidingly receive said plurality of second, lower, pipe sections respectively.
  • this first or second aspect of the invention there is further provided a ' spacer connected to each of said plurality of second, lower, rigid pipe sections pipes, or to each of said plurality of first, upper, rigid pipe sections so as to maintain said plurality of second, lower, pipe sections pipes or each of said plurality of first, upper, rigid pipe sections in a fixed position relative to the other second, lower, rigid pipe sections or first, upper, rigid pipe sections.
  • the spacer is provided at a point on said second, lower, rigid pipe section below a lower extremity of said buoyancy section.
  • first or second aspect of the invention the substantially right-angled joins between respective second, lower, rigid pipe sections and first, upper, rigid pipe sections are spaced apart from one another along the length of said buoyancy section.
  • the buoyancy section is made of a foam.
  • the buoyancy section is a tube arranged such that the rigid pipe runs therethrough.
  • the buoyancy section is made of steel or aluminium or a composite material.
  • the solid tube arranged is arranged coaxially to said second, lower, rigid pipe section.
  • the buoyancy section further comprises a plurality of bulkheads dividing said buoyancy section into a plurality of closed chambers.
  • At least one valve is provided allowing flow of a fluid from inside said rigid pipe to the interior of a respective at least one of said closed chambers.
  • At least one valve is provided allowing flow of a fluid from inside a respective at least one of said closed chambers to the exterior of said buoyancy unit.
  • an upper extremity of said second, lower, rigid pipe is aligned away from the axis of the part of said riser immediately below said upper extremity.
  • a riser having a lower section and an upper section, said lower section being substantially longer than said upper section, said second, lower, rigid pipe section further comprising a buoyancy section at or in the region of an upper end of said second, lower, rigid pipe section, said method involving the steps of;
  • a riser having a lower section and an upper section , said lower section being substantially longer than said upper section, said second, lower, rigid pipe section further comprising a buoyancy section at or in the region of an upper end of said second, lower, rigid pipe section, said method involving the steps of;
  • one or more temporary buoyancy elements are connected to said riser such that buoyancy is distributed along the length of the riser substantially evenly
  • the lower end of said second, lower, rigid pipe section is connected to said well head or flowline by means of jumpers or spools.
  • the second, lower, rigid pipe section and the buoyancy section are towed out to sea to the location where the riser is to be installed further using a second tug and a second tether, said second tether being connected to a point along the second, lower, rigid pipe section behind the point to which said first tether is connected.
  • the second, lower, rigid pipe section pipe is pressurised with a gas prior to said step of expelling fluid from the buoyancy unit.
  • a riser having a lower section and an upper section , said lower section being substantially longer than said upper section, said second, lower, rigid pipe section further comprising a buoyancy section at or in the region of an upper end of said second, lower, rigid pipe section , said method involving the steps of; i. lowering said second, lower, rigid pipe section into the sea by reeling or by lowering successive lengths of rigid pipe section into the sea, each length being connected endwise to the length of pipe section below it, ii.
  • Figure 1 is a side view showing a riser configuration according to a first arrangement known in the prior art
  • Figure 2 is a corresponding view of a second, riser configuration known in the prior art
  • Figure 3 is a side elevation of a third riser configuration known in the prior art
  • Figure 4 is a side view of a riser configuration known in the prior art
  • Figure 5 is a side view of a fifth riser configuration known in the prior art
  • Figure 6 is a side view of a first embodiment according to the present invention.
  • Figure 7a is a side view of a second embodiment according to the present invention.
  • Figure 7b is a side view of a second variant of the second, embodiment of the present invention as shown in Figure 7a;
  • Figure 8 is a side view of a third embodiment of the present invention.
  • Figure 9 shows a fourth embodiment of the present invention.
  • Figure 10 shows a fifth embodiment of the present invention
  • Figure 11 shows details of the buoyancy unit incorporated in an embodiment of the present invention
  • Figure 12a shows details of the buoyancy unit 16 incorporated in an embodiment of the present invention in a first state
  • Figure 12b shows details of the buoyancy unit 16 incorporated in an embodiment of the present invention in a second state
  • FIG 13 shows details of the buoyancy unit 16 incorporated in an embodiment of the present invention
  • Figure 14 shows details of the buoyancy unit 16 and the lower rigid catenary pipe section 13 incorporated in an embodiment of the present invention
  • Figure 15 shows details of the buoyancy unit, the upper portion of the rigid catenary pipe section and the flexible riser of Figure 9;
  • Figure 16a shows a sixth embodiment of the present invention.
  • Figure 16b shows a cross-section through the diameter of the buoyancy unit (16) of figure 16 a through the line AA.
  • Figure 16c shows a cross-section through the diameter of the riser pipes of figure 16a through the line BB
  • Figure 17a shows a further development of the sixth embodiment of the invention.
  • Figure 17b shows in further detail the configuration of the elements shown in Figure 17a at a cross-section through the line AA.
  • Figure 17c shows in further detail the configuration of the elements shown in Figure 17a at a cross-section through the line BB.
  • Figure 18a shows a combination of the embodiments of Figure 6 and Figure 17a.
  • Figure 18b shows in further detail the configuration of the elements shown in Figure 18a at a cross-section through the line AA.
  • Figure 18c shows in further detail the configuration of the elements shown in Figure 18a at a cross-section through the line BB.
  • Figures 19a to 19e show stages of a method of installing a riser of an embodiment of the present invention.
  • Figures 20a to 20 e shows a further method of installing a riser according to any proceeding embodiment.
  • Figure 21 shows the use of a first controlled depth towing method.
  • Figure 22 shows the use of a second, controlled depth towing method.
  • Figure 23 shows the use of a third towing method.
  • Figure 24 is a cross-section through a riser arrangement according to a further aspect of the invention.
  • Figure 25 shows the same arrangement as Figure 24, but with the section taken directly adjacent a spacer connecting the service riser pipes to a central core pipe, and
  • Figure 26 is a diagram showing the creation of buoyancy in the core pipe of Figure 25.
  • Figure 6 shows a first embodiment of the present invention.
  • a riser ascends to a surface vessel 3 from the seabed 2, and comprises a first, upper, rigid pipe section 10 connected to said surface vessel 3 and the top part of a second, lower, rigid pipe 13 having the configuration of a catenary, which is further connected to a wellhead on the seabed 2.
  • the first, upper, and second, lower, rigid pipe sections according to this and all embodiments of the present invention will generally be made of a metal or alloy.
  • the pipe sections will mast generally be made of steel.
  • Other materials may be envisaged, for example, composite material or titanium composite or other material which is substantially rigid, and sufficiently rigid to form a catenary in accordance with the present invention.
  • the first, upper, rigid pipe section is also preferably substantially shorter that the second, lower, rigid pipe section.
  • the surface vessel 3 may be a ship, a semi-submersible unit, a Tension Leg Platform, a Spar platform or other surface vessel as appropriate.
  • the riser may alternatively be terminated at a riser base, and thus not extended all the way to the well head. It may also be used as an export riser.
  • the second, lower, rigid portion 13 is held substantially immobile in the sea by the buoyancy unit 16.
  • the first, upper, rigid riser portion 10 absorbs the motion of the surface vessel 3, and other forces exerted thereon, for example by the movement of the sea itself.
  • first, upper, rigid pipe and second, lower, rigid pipe are steel pipes.
  • Figure 6 to 10 show the surface vessel 3 as being distant from the well head, it will be appreciated that the arrangement of the present invention also allows for the situation of the surface vessel above the well head. In this, and other cases, the first, upper, rigid pipe section will depart from the buoyancy unit at a different location and angle to those shown in Figures 6 to 10.
  • the first, upper, rigid pipe 10 is attached to the upper end of the second, lower, rigid pipe 13 at right angles and hangs suspended in the water in the configuration of a catenary.
  • a tether 17 may be provided between the buoyancy unit 16 and surface vessel 3, or alternatively, a tether 17b may be provided between the upper part of the buoyancy unit 16 and a point on the sea surface or seabed.
  • This arrangement is advantageous over the prior art as embodied for example by the tower riser as discussed above, in that the demands of anchoring the rigid riser to the seabed are reduced, there is no requirement for a flexible joint, and the degree of buoyancy required is reduced.
  • the first, upper, rigid pipe adopts a catenary configuration, it is able to flex to as to absorb some movement of the surface vessel with respect to the buoyancy unit, without exerting excessive force on the joint of the two rigid pipes at the buoyancy unit. It may however be desirable to make this joint flexible, so as to remove the fatigue effects that may otherwise be experienced.
  • a tether 17c is connected between the upper part of the second, lower, rigid section 13, and the sea floor. It has been found to be highly advantageous in terms of the stability of the riser, and the limitation of fatigue thereto, to connect the seabed tether 17c to the second, lower, rigid pipe 13 just over the high bending area, instead of at the buoyancy tank as described with regard to the tether 17b. It may nonetheless be found desirable to use this configuration in addition to the configuration of tethers 17b and 17.
  • An alternative location for the tether is shown as 17d, in which the tether is connected to the rigid section 13 well down the length of that section.
  • FIG. 7b A variation of this second, embodiment is shown in Figure 7b, where the tether 17 is further provided with at least one tensioning weight 18, which causes the tether 17 to deviate from a substantially straight line between the surface vessel 3 and the top of the buoyancy unit 16.
  • a variation of this is to use at least one heavy tether segment such as a chain segment for example.
  • the second, lower, rigid pipe section 13 comprises a plurality of individual rigid pipes bundled together.
  • the pipes are intended for carrying the same or different fluids, selected from production fluid, natural gas, injection air and water, for example.
  • First, upper, rigid riser sections 10a, 10b, 10c, 10d, etc. are coupled at right angles to respective second, lower, rigid pipes in the second, lower, rigid section 13, at intervals along the parts of the second, lower, rigid pipe section along which extends the buoyancy unit 16.
  • connection of the respective first, upper, and second, lower, rigid pipes of each pair may be effected without interference from an adjacent pair during installation of the riser structure.
  • Figure 9 shows an equivalent structure to that of Figure 8, but with the further provision of a tether 17 between the top of the buoyancy unit 16 and the sea surface 1.
  • this tether has the effect of reducing the forces exerted on the first, upper, rigid sections 10a, 10b, 10c, 10d, etc.
  • a tether 17c is connected between the upper part of the second, lower, rigid section 13, and the sea floor. It has been found to be highly advantageous in terms of the stability of the riser, and the limitation of fatigue thereto, to connect the seabed tether 17c to the second, lower, rigid pipe 13 just over the high bending area, instead of at the buoyancy tank as described with regard to the tether 17b. It may nonetheless be found desirable to use this configuration in addition to the configuration of tethers 17b and 17.
  • An alternative location for the tether is shown as 17d, in which the tether is connected to the rigid section 13 well down the length of that section.
  • a top section of the second, lower, rigid section extends beyond the upper end of the buoyancy unit and deviates from the line defined by the essentially vertically rising section of the second, lower, rigid section.
  • the top of the second, lower, rigid section 13 and the buoyancy unit 16 may be desirable to pre-form the top of the second, lower, rigid section 13 and the buoyancy unit 16, such that a top section of these two elements 16a deviates from the line defined by the essentially vertically rising section of the second, lower, rigid section.
  • FIG 11 shows further detail of the buoyancy unit 16 used in Figure 6 (or in any of Figures 7 to 10 with obvious adaptation).
  • the buoyancy unit comprises an essentially tubular structure arranged coaxially with the second, lower, rigid section 13.
  • the buoyancy unit is made of any suitable buoyant material, for example a foam. It may alternatively comprise a rigid hollow buoyant tank made of steel, composite material, aluminium or other materials as will readily occur to the skilled person, which is either an intrinsic part of the upper section of the second, lower, rigid section, or a separate tubular structure which is secured thereto. Such a tank may be filled with gas, or a foam or other buoyant material.
  • FIG 12a shows the structure of the buoyancy unit 16 according to a preferred configuration.
  • the buoyancy unit 16 is formed by positioning the second, lower, rigid section 13 coaxially inside a second, lower, pipe of larger diameter, such that a tubular space is formed between the two pipes.
  • Six annular bulkheads are provided in this tubular space, so as to divide it into five separate tanks.
  • valves 22a and 22b are provided between the inside of said second, lower, rigid pipe 13, and the inside of a second, and fourth of said tubular spaces 21a and 21 b.
  • a further two valves 23a and 23b are provided between said second and fourth tubular spaces 21a and 21 b, and the outside of said buoyancy unit 16.
  • the ends of the second, lower, rigid pipe 13 are sealed, and the second, lower, rigid pipe is pre-pressurised, for example with nitrogen (N 2 ) gas.
  • First, third and fifth tubular spaces 20a, 20b and 20c are similarly filled with gas.
  • the second and fourth tubular spaces 21a and 21 b are filled with seawater, or another fluid having a higher density than the gas with which the second, lower, rigid pipe 13 is filled.
  • the buoyancy tank compartments may be filled with a light weight fluid during tow out, which makes the buoyancy section close to neutrally buoyant. This fluid will be replaced by gas (compressed nitrogen or similar) during (prior to or after) the upending operation (i.e. when the buoyancy tank is elevated into it's final position).
  • the gas is supplied from a surface vessel, or from compressed gas in the pipelines, or from compressed gas in the buoyancy tank.
  • the number and configuration of the tanks into which the tubular space is divided may be varied as expedient. It may also be found advantageous to provide tubing connecting the different valves, or Jo connect one or more chambers together by tubing such that they can be vented through a common valve, or other arrangements so as to facilitate the transfer of fluids to and from the buoyancy unit. It may further be found to be advantageous to provide means such that the transfer of fluids to and from the buoyancy unit can be effected after the installation of the riser.
  • Figure 12b shows the riser 16 of the same preferred embodiment of Figure 12a, in a second state.
  • the valves 22a, 22b, 23a and 23b can be opened, such that the water in the second, and fourth tubular spaces 21a and 21 b is expelled through valves 23a and 23b, and displaced by the pressurised gas from said second, lower, rigid pipe 13, which flows into said second and fourth tubular spaces through said valves 22a and 22b.
  • Figure 13 shows a further configuration of the structure of the buoyancy unit 16, in which a tubular gap 32 is provided between the second, lower, rigid pipe 13 and the buoyancy unit 16.
  • This gap 32 is defined by the inner wall 33 of the buoyancy unit 16 and the outer wall 31 of the second, lower, rigid pipe 13.
  • This gap is provided to provide insulation between the fluids flowing through the second, lower, rigid pipe 13 and the surrounding seawater.
  • the gap may be filled with a gas, a fluid or any other insulating material, and may further comprise spacers to maintain the coaxial configuration of the second, lower, rigid pipe 13 and the buoyancy unit 16.
  • riser pipes such as that shown in Figure 13 so as to form a bundle, where each pipe has its own buoyancy sleeve.
  • the number and configuration of the riser pipes may be varied as expedient.
  • the second, lower, rigid pipes may be arranged such that the bundle describes a circle in cross section, or a "flat pack" arrangement, in which the separate pipes are arranged in rows, or other arrangements as may be found to be advantageous.
  • Figure 14 shows details of a further design for the buoyancy unit 16 and the rigid riser 13, in which the structure of the buoyancy unit 16 is extended along the entire length of the second, lower, rigid pipe 13.
  • a lower portion of the buoyancy unit 16 is reduced in outer diameter, such that the external diameter of the structure is reduced, the internal diameter of the second, lower, rigid pipe 13 remaining constant.
  • the cross-sectional area of insulating material which may for example comprise gas, foam, gel etc, and may be different in the buoy section than in the riser within the buoyancy unit 16 in this lower section is thus reduced.
  • the lower section of the buoyancy unit 16 extends along the length of the rigid riser 13 so as to perform an insulating function.
  • each pipe has its own buoyancy sleeve.
  • the number and configuration of the riser pipes may be varied as expedient.
  • the rigid pipes may be arranged such that the bundle describes a circle in cross section, or a "flat pack" arrangement, in which the separate pipes are arranged in rows, or other arrangements as may be found to be advantageous.
  • Figure 15 shows further details of the buoyancy unit 16 according to the embodiment of the present invention shown in Figure 9.
  • the second, lower, rigid pipe 13 comprises a bundle of rigid pipes, which are at their upper ends with respective first, upper, rigid pipes perpendicular thereto, at lateral positions spaced longitudinally along the upper portion of the buoyancy unit 16.
  • first, upper, rigid pipes 10a, 10b, 10c, 10d, 10e and 10f there are provided six second, lower, rigid pipes, which are connected respectively to first, upper, rigid pipes 10a, 10b, 10c, 10d, 10e and 10f.
  • a tether 17 connected to an upper surface of said buoyancy section 16.
  • the number and configuration of the riser pipes may be varied as expedient.
  • the rigid pipes may be arranged such that the bundle describes a circle in cross section, or a "flat pack" arrangement, in which the separate pipes are arranged in rows, or other arrangements as may be found to be advantageous.
  • FIG 16 shows a sixth embodiment of the present invention.
  • two hybrid risers ascend to a surface vessel (3) from the seabed (2), each comprising a first, upper, rigid pipe section (101 , 102) which may be made for example of standard steel pipe, composite material or titanium composite or other material which is substantially rigid, and sufficiently rigid to form a catenary in accordance with the present invention., connected to said surface vessel (3), and the top part of a second, lower, rigid pipe (131 , 132) having the configuration of a catenary, and a lower extremity thereof may further be connected to a wellhead on the seabed (2).
  • the surface vessel (3) may be a ship, a semi- submersible unit, a tension leg platform, a spar platform or other surface vessel as appropriate.
  • the riser may alternatively be terminated at a riser base, and thus not extend all the way to the wellhead. Such a riser may also be used as an export riser or indeed in any other such application.
  • a buoyancy unit (16) disposed between the first, upper, riser, and the second, lower, riser.
  • the buoyancy unit (16) is of a substantially elongate shape, such that its length is many times its diameter and is arranged along the length of the upper part (131) and (132) of the second, lower, rigid risers respectively.
  • the buoyancy unit is made of any suitable buoyant material, for example a foam.
  • It may alternatively comprise a rigid hollow buoyant tank made of steel, composite material, aluminium or other materials as will readily occur to the skilled person, which is either an intrinsic part of the upper section of the second, lower, rigid pipe , or a separate tubular structure which is secured thereto.
  • a tank may be filled with gas, or a foam or other buoyant material.
  • each second, lower, rigid riser may be connected to the buoyancy unit (16) by means of a hang-off arrangement or other bearing or fixture (251 , 252), or may simply be welded or otherwise fixed thereto.
  • a similar arrangement may be provided at other points along the length of the buoyancy unit (16).
  • one or more sleeves (261 , 262) may be attached to the buoyancy unit, with the second, lower, rigid pipe (131, 132) fitting slidingly through the sleeve.
  • the mutual spacing of the riser pipes (131 , 132) can be maintained below the lower extremity of the buoyancy unit (16) by means of a spacer (29) situated between two clamps (271 , 272), each clamp connecting to the second, lower, rigid pipes riser (131 , 132) respectively.
  • the clamps may connect the riser fixedly or slidingly, so as to allow for expansion.
  • the two second, lower, rigid pipes (131 , 132) can be retained in a parallel or other desired configuration as they descend in a catenary manner to the sea floor. It may be desirable to employ spacers of different lengths along the length of the risers, so that the separation thereof changes as a function of distance from the sea bed.
  • FIG 16b shows a cross-section through the diameter of the buoyancy unit (16) through the line AA.
  • Figure 16c shows a cross-section through the diameter of the riser pipes (131 , 132) through the line BB, in which can be seen more clearly the configuration of the clamps (271 , 272), the risers (131 , 132) and the spacer bar (29).
  • riser structure using conventional methods whilst at sea such as J-lay, reeling etc.
  • pipe sections For example, by adding pipe sections to the riser one by one as the pipe is deployed from a surface vessel. It may be appropriate to land the buoyancy tank 16 on the seabed and start reeling from there.
  • FIG. 17a shows a further development of the sixth embodiment of the invention, wherein four riser pipes (131 , 132, 133, 134) are disposed around a buoyancy unit (16).
  • the risers may be maintained in position by hang-off units (251 , 252, 253 and 254), and sleeves (261 , 262, 263, 264) respectively.
  • the risers can be retained in a desired configuration below the lower extremity of the buoyancy unit (16) by means of clamps (271 , 272, 273, 274), held in position by a spacer element (29).
  • Figures 17b and 17c show cross-sections through the lines AA and BB respectively and show in further detail the configuration of the elements shown in Figure 17a.
  • Figure 18a shows a combination of the embodiments of Figure 6 and Figure 17, in which a first, upper, riser is arranged concentrically with a buoyancy unit (16), such that the riser is surrounded by the buoyancy unit, while a further four risers (131 , 132, 133 and 134) are arranged around the outside of the buoyancy unit (16).
  • the external riser pipes (131 , 132, 133 and 134) may be maintained in position by hang-off elements (251 , 252, 253 and 254) and sleeves (261 , 262, 263 and 264) as described in relation to Figure 17.
  • All five risers (13, 131 , 132, 133 and 134) can be retained in a desired configuration, for example one similar to that imposed by the arrangement of the risers through and around the buoyancy unit (16) respectively, by means of clamps (271 , 272, 273 and 274).
  • the central riser 13 may be replaced by a plurality of risers.
  • Figures 18b and 18c show cross-sections through the lines AA and BB respectively and show in further detail the configuration of the elements shown in Figure 18a.
  • first, upper, rigid pipe sections there is no requirement for the number of first, upper, rigid pipe sections to equal the number of second, lower, rigid pipe sections.
  • each of the one or more second, lower, rigid pipe sections may be coupled to two or more first, upper, rigid pipe sections.
  • the diameters of first, upper, sections may be chosen such that cross section area of all of the first, upper, rigid sections is equal to that of all of the second, lower, rigid pipe sections, so that no pressure change occurs at the transition from the second, lower, rigid pipe section to the first.
  • Such arrangements have the advantage that smaller diameter first, upper, rigid pipes are more flexible, and thus adopt the desired curve in a shorter length of pipe than is necessary for larger diameter pipes, and can act more effectively to absorb movement of the surface vessel relative to the buoyancy unit.
  • Figures 19a to 19e show a method of installing a riser according to any one of the preceding embodiments.
  • Figure 19a shows a first step in this method of installing the riser, in which the first, upper, rigid pipe section, the second, lower, rigid pipe section 13 which may be typically in the order of seven kilometres long, and the buoyancy section 16 are constructed on land.
  • the first, upper, and second, lower, rigid pipe sections and the buoyancy section 16 are then towed out to sea by a tug 42 using a tether 44, according to a procedure sometimes known as a "bundle tow".
  • Figure 19b shows a second step in the method of installing the riser.
  • the first, upper, and second, lower, rigid pipe sections and the buoyancy section 16 are towed out to sea by at least one tug 42 and tether 44, and optionally a second tug 43 and tether 45.
  • the buoyancy unit 16 is preferably partially flooded, such that the riser as a whole has substantially neutral buoyancy.
  • this is realised according to the buoyancy unit of Figure 12 of the present invention, whereby annular spaces 21a and 21b are flooded with water, and the first, upper, and/ or second, lower, rigid pipe section is pre-pressurised with nitrogen gas.
  • Figure 19c shows a third step of the method of installing the riser.
  • Figure 19d shows a fourth step in the method of installing the riser according to the present invention.
  • the water flooding the ring-shaped spaces 21a and 21b is expelled by opening the valves 22a and 22b, such that the average density of the buoyancy section 16 decreases, and a buoyancy force is exerted on the buoyancy section 16 towards the surface of the sea.
  • a tether 44' which may or may not be the same tether as used to tow the riser into position
  • the buoyancy section is allowed to rise towards the surface of the sea, causing the second, lower, rigid pipe 13 to bend upwards to form a catenary configuration.
  • the first, upper, rigid riser may be supported and lifted in synchronicity with the upward movement of the buoyancy unit by means of one or more tethers 17d connected to a surface vessel.
  • Figure 19e shows a fifth and final step in the method of installing the riser.
  • a tether 17 is attached to a surface vessel or installation vessel 3, and the free end of the first, upper, rigid riser pipes 10a, 10b, 10c, 10d, is further lifted by means of the tether 17d, until it reaches the seas surface, whereupon it can be connected to said surface vessel 3, as discussed above with reference to Figure 9.
  • step d where the buoyancy section is allowed to rise towards the surface of the sea, causing the second, lower, rigid pipe 13 to bend upwards to form a catenary configuration, may in fact take place before the free end of the second, lower, rigid pipe 13 is connected to the wellhead 41.
  • the riser structure using conventional methods whilst at sea such as J-lay, reeling etc.
  • pipe sections to the riser one by one as the pipe is deployed from a surface vessel.
  • reeling it may be appropriate to land the buoyancy tank 16 on the seabed and start reeling from there.
  • successive lengths of rigid pipe section in the sea each length being connected endwise to the length of pipe section below it.
  • a lower end of a further length of rigid pipe section having a buoyancy section comprising an elongate buoyancy unit extending lengthwise of said further length of rigid pipe section is connected to an upper end of the length of rigid pipe section immediately below it, to form the second, lower, rigid pipe.
  • a further length of rigid pipe is then connected to the free eng of the buoyancy section, followed by further successive lengths of rigid pipe section, each length being connected endwise to the length of pipe section below it , to form the first, upper, rigid section, whilst the buoyancy unit is allowed to sink and a lower end of the rigid pipe is connected to a wellhead.
  • the positions of the floating vessel and the buoyancy unit are adjusted such that the first, upper, rigid pipe assumes the configuration of a catenary in the between the surface vessel and the buoyancy unit, and the second, lower, rigid pipe assumes the configuration of a catenary between the buoyancy unit and the sea floor.
  • Figures 20a to 20e shows a further method of installing a riser according to any proceeding embodiment.
  • FIG 20a shows a first step in this method of installing the riser, in which the buoyancy section 16 is constructed on land.
  • the buoyancy section 16 Is transported to the installation site on a vessels deck or on cantilever beams outside ship-side or is alternatively towed out to sea by a tug 42 using a tether 44, according to a procedure similar to that sometimes known as bundle tow.
  • Figure 20b shows a second, step in the method of installing the riser.
  • the buoyancy unit 16 is towed out to sea by at least one tug 42 to tether 44, and optionally a second tug 43 and tether 45.
  • the buoyancy unit 16 is preferably partially flooded, so as to have substantially neutral buoyancy. Preferably, this is realised according to buoyancy unit of figure 12 of the present invention, whereby annular spaces 21a and 21b are flooded with water.
  • Figure 20c shows a third step in the method of installing the riser.
  • Figure 20d shows a fourth step in the method of installing the riser according to this embodiment of the present invention.
  • a cable connected between the buoyancy unit 16, which is eventually to be connected to the second, lower, rigid pipe 13 is connected to an installation surface vessel 31 or another surface vessel.
  • the installation surface vessel 31 then proceeds to lower rigid pipe according to a known method, for example J-lay, S-lay or reeling.
  • the rigid pipe 13 is lowered so as to eventually connect to the end of the buoyancy unit intended therefore.
  • the tether 45, or other tether connecting a surface vessel with the end of the buoyancy unit 16 intended for connection to the rigid riser may be used to guide the end of the second, lower, rigid pipe 13, so as to correctly come into contact with the end of the buoyancy unit intended therefore.
  • Figure 20e shows a fifth step in the method of installing the riser according to this embodiment of the invention.
  • the lower extremity of the rigid pipe 13 has come into connection with the end of the buoyancy unit 16 to which it is to be connected.
  • the connection between these two elements is then made, for example by means of clamps, which may be controlled for example by remote control from the surface.
  • clamps which may be controlled for example by remote control from the surface.
  • the tether 45 or other tether connecting the end of the buoyancy unit 16 intended to be connected to the ridged pipe, and a surface vessel can also be used at this stage for insuring the proper relative position of the buoyancy unit 16 and the ridged pipe 13, for the correct functioning of the clamps.
  • the opposite extremity of the second, lower, rigid pipe section 13, that is the end of this pipe furthest from the end of this pipe connected to the buoyancy unit 16, is released, and lowered to the seabed, where it is connected to the well head 41 or to another pipeline termination point, in a conventional manner.
  • the buoyancy of the buoyancy unit 16 can be increased, for example by evacuating sea water from the flooded tanks 21a and 21 b, so that the buoyancy unit 16 floats towards the sea surface, as described with reference to figures 19d and 19e above.
  • the installation of the riser is thus complete, and hydrocarbon transport may commence.
  • the skilled person will appreciate that variations may be made to the sequence in which the above steps are carried out.
  • the step where the buoyancy section is allowed to rise toward the surface of the sea, causing the second, lower, rigid pipe section to bend upwards to form a catenary configuration may in fact take place before the end of the second, lower, rigid pipe section 13 furthest from the buoyancy unit 16 is connected to the well head 41 or to another pipeline termination point.
  • the entire riser structure comprising at least one first, upper, rigid pipe section 10, at least one corresponding second, lower, rigid pipe section 13 connected thereto as described above and the buoyancy unit 16 disposed along and the lengthways of the second, lower, rigid pipe section nearest said first, upper, rigid pipe section on land, before towing the whole structure out to be installed at sea.
  • the buoyancy unit 16 preferably has a length equal to at least twice its diameter. More preferably, the buoyancy unit 16 has a length equal to at least thirty times its diameter. Yet more preferably, the buoyancy unit 16 has a length equal to at least 100 times its diameter.
  • the towed part may be towed using any conventional towing method.
  • any conventional towing method For example,
  • Figure 21 shows the use of a first controlled depth towing method.
  • a plurality of chains 301 is attached to the pipe 13,16 being towed.
  • the pipe is preferably weighted, possibly by being partially flooded, so as to have slightly positive buoyancy on its own, and slightly negative buoyancy when weighted down by the chains.
  • the chains 301 have two effects. Firstly, whilst the pipe is in motion, the chains generate lift, which, when the movement of the pipe through the water exceeds a given velocity, leads to the pipe "flying" in the water. When the tow rate decreases, the pipe sinks gently back towards the sea floor 2. When this occurs, the hanging chains come into contact with the sea floor before the body of the pipe 13 itself.
  • the part of the chin touching the sea floor no longer contributes to the overall weight of the apparatus, so that the pipe ceases to sing as equilibrium is reached between the positive buoyancy of the pipe, and the weight of the chains, so that the pipe remains suspended at a given height above the sea bed.
  • Figure 22 shows the use of a second, controlled depth towing method.
  • This method has common features with the method described above with regard to figure 21.
  • the lift is provided by aqua foils 302.
  • the pipe is weighted, possibly by being partially flooded, so as to have slightly negative buoyancy on its own, which is counteracted by the lift generated by the aquafoils 302 as the apparatus moves through the water.
  • the attitude of the pipe in the water can be controlled.
  • Figure 23 shows the use of a third towing method.
  • the pipe is simply dragged along the sea floor.
  • the pipe is preferably provided with a sleigh or runners 303 to as to reduce the drag of the pipe along the sea floor, and to protect the pipe from wear.
  • each riser is provided with its own foam (e.g. "PU foam") buoyancy material 306.
  • the core is not a service conduit, but a structural member for interconnecting the seabed foundation, to which the risers are to be connected, and a subsea flotation device which is used to tension the risers vertically.
  • the core 302 is designed in the manner illustrated in Figure 26.
  • the core 302 is shown in four different stages of its operation when installed in a nominally vertical attitude below sea (though it may assume a tilted attitude in certain applications).
  • the core is divided into a number of individual sections or compartments 310-315 and bridging each adjacent pair of compartments is a tube 320-325.
  • a valve 330-335 near the bottom of each compartment.
  • the liquid medium may be seawater, fresh water, a gel or even a glass-sphere mix. Corrosion inhibitors may also be introduced, where appropriate.
  • the next step is to introduce a gas at high pressure into the bottom end of the core, following which the bottom valve 335 is opened. Since the pressure of the gas is higher than that of the surrounding seawater, the liquid medium is forced out of the bottom compartment into the sea via the bottom valve 335.
  • the liquid level in the bottom compartment 315 drops until it reaches to just below the lower open end of the bottom tube 325, upon which the gas enters the tube and passes into compartment 314. At this point the liquid in compartment 314 starts to exit from the valve 334. The liquid level in compartment 314 drops until it eventually reaches the lower open end of tube 324, upon which the gas passes along this tube and into compartment 313, and so on. Once the top compartment has been filled with gas the gas supply is removed.
  • the valve associated with that compartment When the liquid medium in any compartment has reached its minimum level, the valve associated with that compartment is closed.
  • the pressure of the gas in that compartment has the same value as that of the surrounding water at that particular depth and therefore the pressure in each gas-filled compartment counterbalances the hydrostatic pressure of the water at the relevant depth.
  • the core need not be designed to withstand the maximum surrounding hydrostatic pressure, but a lesser value of pressure resistance can be tolerated, thereby saving costs in core materials. (As a rough figure, the core can be designed to typically less than 20% of the fully hydrostatic pressure).
  • the cost reduction can take the form of a reduction in the thickness of the core wall and/or a downgrading of the core material. In addition, of course, there is the original saving in costs brought about by the elimination of the need to use a syntactic foam.
  • Figure 26 shows the use of six risers in the bundle, more or less than six may be included, depending on requirements. Also, it is not a requirement that the risers, however many are used, be equidistantly spaced from each other or from the core. Indeed, the riser pipes may be spaced apart in a line with the "core” (i.e. "further pipe”), with the further pipe situated either adjacent one of the riser pipes on the same line or displaced from the line. In this case, of course, the further pipe cannot strictly speaking be called a "core".
  • core i.e. "further pipe
  • the riser arrangement shown in Figures 24-25 can be employed as part of the riser described earlier and as illustrated in, for example, Figure 18.
  • the service pipes would represent the risers 131-134 and the further pipe (core pipe) would represent the riser 13.
  • the buoyancy material 16 could be dispensed with or employed in reduced form.
  • the riser 13 could be dispensed with and the buoyancy element 16 realised as a cascade core as shown in Figure 26.
  • valves In practice, however, it is preferred for the valves to be closed after the venting of their respective compartments. This is because, where the valves remain open, any appreciable vertical movement of the core could cause a transfer of fluid into/ out of the compartments from/to the surrounding environment due to the finite pressure differences created by such movement, and this is considered to be undesirable.
  • the reduction in core wall-thickness which this invention allows can result in increased buoyancy solely by virtue of a decrease in weight in the core.
  • buoyancy can also be enhanced by converting some of reduction in wall thickness to an increase in core diameter, which creates a higher internal core volume and hence an increase in buoyancy when gas is introduced.
  • the advantage of this is that the individual supplementary foam material 306 provided for each service riser can be even further reduced in volume or even dispensed with altogether. The same applies to any foam that would normally be used to surround the core.

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  • Physics & Mathematics (AREA)
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  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
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Abstract

La présente invention concerne un tube prolongateur présentant un premier tronçon de canalisation (6) rigide, supérieur et un second tronçon de canalisation (10) rigide, inférieur, le tronçon inférieur étant sensiblement plus long que le tronçon supérieur, le second tronçon de canalisation rigide, inférieur, comprenant également un tronçon de flottabilité (16) au niveau ou à proximité d'une extrémité supérieure du second tronçon de canalisation rigide, inférieur, et forme une caténaire (13) en communication avec le premier tronçon de canalisation rigide, supérieur, ce dernier formant une caténaire entre le tronçon de flottabilité et un navire à la surface de la mer. Le tronçon de flottabilité (16) comprend également un élément de flottabilité cylindrique allongé, lequel peut présenter une construction tubulaire compartimentée, coaxiale présentant des vannes de sorte qu'il peut être inondé ou vidangé de manière contrôlée. Le tube prolongateur peut être amarré à un navire de surface ou à un fond marin. Le tube prolongateur peut être construit sur terre et remorqué près de l'installation à laquelle il doit être relié.
PCT/EP2003/010774 2002-10-10 2003-09-26 Tube prolongateur et son procede d'installation Ceased WO2004033848A1 (fr)

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WO2007125276A1 (fr) * 2006-04-27 2007-11-08 Wellstream International Limited Ensemble de colonne montante
WO2007127684A3 (fr) * 2006-04-26 2008-01-10 Technip France Procédé de remorquage et d'installation pour pipelines et colonnes montantes en eaux profondes
WO2009124334A1 (fr) * 2008-04-09 2009-10-15 Amog Technologies Pty Ltd Support de colonne montante
WO2009138609A3 (fr) * 2008-04-24 2010-05-20 Saipem S.A. Installation de liaison fond-surface d'une conduite rigide avec une conduite flexible a flottabilite positive
US8231308B2 (en) 2005-06-18 2012-07-31 Acergy France Sa Hybrid riser tower and method of installation thereof
FR2984396A1 (fr) * 2011-12-19 2013-06-21 Total Sa Installation de transfert de fluides entre une tete de puits au fond de l'eau et une structure de surface
CN103958818A (zh) * 2011-11-29 2014-07-30 韦尔斯特里姆国际有限公司 浮力补偿元件和方法
EP3280869A4 (fr) * 2015-04-07 2019-01-02 Ensco International Incorporated Atténuation de la déviation d'une colonne montante
CN113558016A (zh) * 2021-07-21 2021-10-29 湖北海洋工程装备研究院有限公司 捕鱼装置及养殖船

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US5615977A (en) * 1993-09-07 1997-04-01 Continental Emsco Company Flexible/rigid riser system
WO2003031765A1 (fr) * 2001-10-10 2003-04-17 Rockwater Limited Tube goulotte et procede d'installation de celui-ci

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US5615977A (en) * 1993-09-07 1997-04-01 Continental Emsco Company Flexible/rigid riser system
WO2003031765A1 (fr) * 2001-10-10 2003-04-17 Rockwater Limited Tube goulotte et procede d'installation de celui-ci

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8231308B2 (en) 2005-06-18 2012-07-31 Acergy France Sa Hybrid riser tower and method of installation thereof
WO2007127684A3 (fr) * 2006-04-26 2008-01-10 Technip France Procédé de remorquage et d'installation pour pipelines et colonnes montantes en eaux profondes
US7559721B2 (en) 2006-04-26 2009-07-14 Technip France Towing and installation method for deepwater pipelines and risers
WO2007125276A1 (fr) * 2006-04-27 2007-11-08 Wellstream International Limited Ensemble de colonne montante
US8702350B2 (en) 2006-04-27 2014-04-22 Wellstream International Limited Riser assembly
WO2009124334A1 (fr) * 2008-04-09 2009-10-15 Amog Technologies Pty Ltd Support de colonne montante
US8430170B2 (en) 2008-04-24 2013-04-30 Saipem S.A. Bottom-to-surface connection installation of a rigid pipe with a flexible pipe having positive buoyancy
WO2009138609A3 (fr) * 2008-04-24 2010-05-20 Saipem S.A. Installation de liaison fond-surface d'une conduite rigide avec une conduite flexible a flottabilite positive
CN103958818A (zh) * 2011-11-29 2014-07-30 韦尔斯特里姆国际有限公司 浮力补偿元件和方法
US9151121B2 (en) 2011-11-29 2015-10-06 Ge Oil & Gas Uk Limited Buoyancy compensating element and method
FR2984396A1 (fr) * 2011-12-19 2013-06-21 Total Sa Installation de transfert de fluides entre une tete de puits au fond de l'eau et une structure de surface
WO2013093294A1 (fr) * 2011-12-19 2013-06-27 Total Sa Installation de transfert de fluides entre une tete de puits au fond de l'eau et une structure de surface
EP3280869A4 (fr) * 2015-04-07 2019-01-02 Ensco International Incorporated Atténuation de la déviation d'une colonne montante
CN113558016A (zh) * 2021-07-21 2021-10-29 湖北海洋工程装备研究院有限公司 捕鱼装置及养殖船

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