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
  • E21B17/10—Wear protectors; Centralising devices, e.g. stabilisers
  • E21B17/1078—Stabilisers or centralisers for casing, tubing or drill pipes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
  • B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
  • B63B21/502—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers by means of tension legs
• • 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
  • E21B17/015—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
  • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
  • E21B17/02—Couplings; joints
  • E21B17/08—Casing joints
  • E21B17/085—Riser connections
• • 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
• • 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
• • 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
  • E21B41/00—Equipment or details not covered by groups E21B15/00 - E21B40/00
  • E21B41/04—Manipulators for underwater operations, e.g. temporarily connected to well heads
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
  • B63B39/08—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by using auxiliary jets or propellers

Definitions

• the present invention provides a method of stabilising a riser connecting a structure on the seabed, such as a wellhead, to the sea surface, the method comprising: applying an oscillating force to the riser using a thrust unit on the riser, so as to counteract an oscillating movement of the riser.
• the thrust unit may be mounted to the riser, for example being formed separately and mounted in accordance with the following method, or the thrust unit may be formed integrally with the riser, for example it could be formed together with one of the riser segments during manufacture.
• the oscillating force from the thrust unit is applied at a location along the length of the riser.
• the precise location will vary depending on a number of factors, such as the particular riser properties, local weather conditions, number of thrust units used, etc., but the location is typically between 10% and 90% along the length of the riser.
• oscillating force and oscillating movement are intended to refer to a force and a displacement, respectively, having a repetitive variation in time.
• the oscillation may be a repeated sinusoidal type variation in time.
• the oscillating movement of the riser to be counteracted preferably has a period of over 1 second.
• the method may comprise the step of locating the thrust unit on the riser, for example by mounting the thrust unit on the riser.
• the method comprises locating the thrust unit on the riser at a predetermined location, this location being selected to maximise the corrective effect of the thrust unit on expected oscillating movements of the riser.
• the method may therefore further comprise: modelling the oscillating movement of the riser; predicting the location of an antinode of the oscillating movement based on the modelling; and locating the thrust unit on the riser at the predicted antinode location.
• the method may include predicting the locations of multiple antinodes and locating multiple thrust units on the riser at two or more of the predicted antinode locations.
• a further oscillating force may be applied to the riser using a second thrust unit configured to be located on the riser at a location axially offset from the first thrust unit.
• the second thrust unit is preferably also positioned at an antinode of the oscillating movement of the riser. However, it may of course be positioned elsewhere.
• the antinode made be an antinode of a different mode of vibration of the oscillating movement of the riser from that of the first thruster.
• the or each thrust unit preferably comprises a pair of thrusters on opposite sides of the riser, wherein first and second thrusters of the pair may be aligned and hence provide thrust in parallel with each other.
• first and second thrusters of the pair may be aligned and hence provide thrust in parallel with each other.
• a first thruster of the pair of thrusters is configured so as to be on an opposite side of the riser to a second thruster of the pair of thrusters, when the frame is mounted to the riser.
• the plurality of pairs of thrusters comprises three pairs of thrusters.
• the present invention provides a computer program product comprising computer readable instructions that, when executed, will cause a processor to perform a method comprising: receiving parameters of a riser; modelling oscillating movement of the riser when connecting a structure on the seabed to the sea surface; and determining a location for a thrust unit on the riser to counteract the oscillating movement based on the modelling.
• the determined location is preferably an antinode of the oscillating movement and may be determined by modelling as discussed above in relation to the methods of the invention and preferred embodiments.
• a resulting thrust force can be generated in any horizontal direction on the riser 106.
• the thrust unit 108 has designed redundancy because only two non-parallel thruster pairs are required to generate a resulting thrust in any horizontal direction. Thus, if any thruster pair 1 10, 1 12, 1 14 fails, for example by one of the thrusters 1 10a, 1 12a, 1 14a, 1 10b, 1 12b, 1 14b becoming ineffective or less effective, the thrust unit 108 can still operate at maximum capacity.
• the optimal locations for mounting the first and second thrust units 120, 122 is determined by the method discussed above.
• the riser 106 in Figure 7 is shown exhibiting oscillating movement having three nodes (at the platform 102, the wellhead 104 and approximately at the middle of the riser 106) and two antinodes (approximately one quarter and three quarters along the length of the riser 106).
• the first and second thrust units 120, 122 are respectively positioned at the antinodes.
• thrust units 108, 120, 122, 208 have been described as units formed separately of the riser 106, they may of course be formed integrally with the riser, for example formed together with a riser segment to be installed in the riser 106 during manufacture.

Landscapes

• Engineering & Computer Science (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Fluid Mechanics (AREA)
• Environmental & Geological Engineering (AREA)
• Physics & Mathematics (AREA)
• Geochemistry & Mineralogy (AREA)
• Mechanical Engineering (AREA)
• Combustion & Propulsion (AREA)
• Chemical & Material Sciences (AREA)
• Ocean & Marine Engineering (AREA)
• Earth Drilling (AREA)
• Excavating Of Shafts Or Tunnels (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
• Underground Structures, Protecting, Testing And Restoring Foundations (AREA)
• Catching Or Destruction (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=51492289

Family Applications (1)

Country Status (6)

Families Citing this family (12)

Citations (1)

Family Cites Families (7)

• 2014
  • 2014-08-13 EP EP14759113.5A patent/EP3033269A2/de not_active Withdrawn
  • 2014-08-13 WO PCT/EP2014/067317 patent/WO2015022357A2/en not_active Ceased
  • 2014-08-13 GB GB1414324.2A patent/GB2517309B/en not_active Expired - Fee Related
  • 2014-08-13 US US14/912,226 patent/US20160201407A1/en not_active Abandoned
  • 2014-08-13 RU RU2016105336A patent/RU2016105336A/ru not_active Application Discontinuation
  • 2014-08-13 BR BR112016002576A patent/BR112016002576A2/pt not_active IP Right Cessation

Patent Citations (1)

Also Published As

Similar Documents

Legal Events