Grout injection

Abstract

A method for applying grout to an offshore structure, comprising determining the required amount of grout to be applied to the offshore structure, and transporting the grout along a grout line connected to the grout application location of the offshore structure. The method also comprises inserting a cleaning pig into the grout line and transporting the cleaning pig along the grout line toward the offshore structure in order to discharge at least a portion of the grout remaining from the grout line to the grout application location.

Claims

1. A method for applying grout to offshore structures, To determine the required volume of grout to be applied to the aforementioned offshore structure, Transporting grout along a grout line connected to the grout application location of the aforementioned offshore structure, To discharge at least a portion of the remaining grout from the grout line to the grout application location, a cleaning pig is inserted into the grout line, and the cleaning pig is transported along the grout line toward the offshore structure. Methods that include...

2. The method according to claim 1, comprising monitoring the volume of grout being transported along the grout line to the grout application location.

3. The method according to claim 1, wherein the cleaning pig is inserted into the grout line when the volume of the remaining grout to be applied to the offshore structure is substantially less than or equal to the volume of the grout line.

4. The method according to any one of claims 1, 2, or 3, wherein the cleaning pig is inserted into the grout line before the grout line is disconnected from the connection point of the permanent grout conduit of the offshore structure.

5. The method according to claim 1, comprising pumping a transfer fluid upstream of the cleaning pig in order to transport the cleaning pig along the grout line.

6. The method according to claim 5, wherein the volume of the transfer fluid being pumped is less than the volume of the grout line.

7. The method according to claim 5, wherein the transfer fluid is water.

8. The method according to claim 7, comprising pumping water from a water storage tank having a volume substantially less than or equal to the volume of the grout line.

9. The method according to claim 7, comprising: transporting grout along the grout line using a grout pump; disconnecting the grout line from the grout pump; connecting the grout line to a water pump; and pumping water upstream of the cleaning pig using the water pump.

10. The method according to claim 1, comprising transporting the cleaning pig along the grout line until the cleaning pig reaches the cleaning pig seat of the grout line.

11. The method according to claim 10, wherein the grout line includes a main grout line and a buffer hose connected to the main grout line and located downstream thereof, and the cleaning pig seat is located at the connection between the main grout line and the buffer hose.

12. The method according to claim 10, wherein the cleaning pig seat is positioned such that 50% to 100% of the remaining grout is discharged from the grout line when the cleaning pig is transported to the cleaning pig seat along the grout line.

13. The method according to claim 10, comprising monitoring the pressure in the grout line upstream of the cleaning pig as the cleaning pig is transported along the grout line, and determining that the cleaning pig has reached the cleaning pig seat by detecting an increase in pressure.

14. The method according to claim 13, wherein the increase in pressure is due to the cleaning pig engaging with the cleaning pig seat, thereby preventing the flow of fluid from the upstream position of the cleaning pig to the downstream position of the cleaning pig.

15. The method according to any one of claims 1, 2, or 3, wherein transporting grout along a grout line includes using a pump to pump grout along the grout line, and monitoring the volume of grout being transported along the grout line to the grout application location includes determining the volume per stroke of the pump and calculating the number of pump strokes since the start of the grout injection operation.

16. The method according to claim 2, wherein monitoring the volume of grout being transported along the grout line to the grout application location includes monitoring the height of the grout at the grout application location relative to a reference mark located on the offshore structure.

17. The method according to claim 1, comprising removing the cleaning pig from the grout line after at least a portion of the remaining grout has been discharged from the grout line, and sealing one end of the grout line.

18. The method according to claim 17, comprising washing the grout line with a cleaning agent to remove residual grout.

19. The method according to claim 1, wherein the offshore structure includes a monopile and a transition piece, and the grout application location is an annular portion defined between the monopile and the transition piece.

20. The method according to claim 19, comprising inserting the cleaning pig into the grout line when the height of the grout overflows the annular portion.

21. A grout injection system for applying grout to an offshore structure, wherein the system includes a grout line, and the system further includes a cleaning pig configured to clean grout from the grout line, wherein, in use, the cleaning pig is received into a first end of the grout line and transported along the grout line from the first end toward the offshore structure in order to discharge at least a portion of the remaining grout from the grout line toward the offshore structure.

22. The grout injection system according to claim 21, comprising a grout pump configured to transport grout towards the offshore structure along the grout line.

23. A grout injection system according to claim 21 or 22, comprising a water supply unit and a water pump, wherein the water pump is configured to pump water from the water supply unit upstream of the cleaning pig in order to transport the cleaning pig along the grout line.

24. The grout injection system according to claim 21, wherein the grout line includes a cleaning pig seat configured to receive and engage with the cleaning pig as the cleaning pig is transported, in order to prevent the flow of fluid from an upstream position of the cleaning pig to a downstream position of the cleaning pig, the cleaning pig seat being positioned such that 50% to 100% of the remaining grout is discharged from the grout line into the offshore structure.

25. The grout injection system according to claim 24, wherein the grout line includes a main grout line and a buffer hose, and the cleaning pig seat is located at the connection between the main grout line and the buffer hose.

26. A water supply system for transporting a cleaning pig along a grout line of a grout injection system according to claim 21, wherein the system includes a water supply unit and a water pump, the water pump being configured to pump water from the water supply unit upstream of the cleaning pig in order to transport the cleaning pig along the grout line.

27. The water supply system according to claim 26, wherein the volume of the water supply unit is less than or equal to the volume of the grout line.

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