Patent Application
20230279630
This invention relates generally to a grout applicator. More specifically, although not exclusively, this invention relates to an apparatus for applying grout to the leg of an offshore structure and a method of fixing an offshore structure to a pre-piled foundation pile.
Offshore structures, commonly present in both the offshore wind and offshore oil and gas industries, most often include a structural jacket supporting a payload above the surface of the water. In the offshore wind industry, the payload is a wind turbine, and in the offshore oil and gas industry, the payload tends to be a processing and/or accommodation platform.
The structural jacket is secured to the seabed via one or more foundation piles, which often take the form of hollow tubes piled into the seabed. In order to secure the structural jacket to the foundation piles, and therefore the seabed, a cementitious material commonly known as grout is applied to the foundation. The grout is applied such that the interface between each foundation pile and respective leg of the jacket is filled. The grout is subsequently left to cure. Conventionally, the grout is applied from pump unit on the surface via a pipe or hose. In particular and most commonly, suitable piping or hoses are provided within the leg(s) and stab portion of the leg(s) of the jacket structure to provide the grout to the desired region(s).
According to an aspect of the invention, there is provided an apparatus for applying grout in a region, e.g. an annular region, between a tubular sub-sea foundation pile and a leg of an offshore structure inserted into the foundation pile, the apparatus comprising a rigid tube adapted or configured to be inserted into the region, the rigid tube comprising an inlet for receiving grout, and an outlet.
The leg of the offshore structure may not comprise any internal and/or integrated means for conveying grout into the tubular sub-sea foundation pile.
The outlet may be disposed in a sidewall of the rigid tube.
The rigid tube may comprise a closed end, e.g. opposite to the inlet end.
The outlet may be disposed in the sidewall of the rigid tube proximate to the closed end.
The leg of the offshore structure may be or comprise a jacket leg. The leg of the offshore structure or jacket may be inserted into an open end of the foundation pile. The foundation pile may be a pre-piled foundation pile.
The rigid tube may comprise a plurality of outlets. The plurality of outlets may be disposed in the sidewall of the rigid tube. The outlets may be circumferentially spaced thereabout. The outlets may be equally spaced circumferentially thereabout.
The sidewall of the rigid tube may comprise markings or indicia. The markings or indicia may provide, or be configured to provide, in use, an indication of the depth to which the outlet is inserted into a foundation pile.
The markings or indicia may provide, or be configured to provide, in use, an indication of the depth to which the rigid tube, closed end or outlet is inserted into a foundation pile.
The markings or indicia may be printed, engraved and/or embossed on or into the sidewall of the rigid tube.
The closed end may be provided by a plug or cap. The plug or cap may be removable. The closed end may be provided by an attached, e.g. welded, metal disc.
The rigid tube may be formed of steel, e.g. stainless steel or galvanized steel. In examples, the rigid tube may be formed of any suitable metal alloy. The rigid tube may be formed of a composite, e.g. carbon fibre reinforced polymer (CFRP).
The apparatus may further comprise a flexible conduit or hose. The flexible conduit or hose may have a first end for connection with a source of grout, for example a pump unit. The flexible conduit or hose may have a second end connected to, or for connection with, the rigid tube.
The rigid tube may be removably connected to or connectable with the flexible conduit or hose.
The first end of rigid tube may be connected to, or for connection with, the flexible conduit or hose.
It will be appreciated that the apparatus is separate from the offshore structure and the foundation pile. For example, the apparatus may be carried onboard, and deployed from, a seagoing vessel, e.g. a supply ship.
By providing the apparatus separate from the offshore structure and the foundation pile, it is reusable such that it can be used on multiple offshore structures. Such an apparatus is particularly beneficial when there is no integrated means for conveying grout into the foundation pile, e.g. a conduit integrated into the offshore structure or foundation pile.
The rigid tube may have an internal, or external, diameter of between 2 and 4 inches. The flexible conduit may have an internal, or external, diameter of between 2 and 4 inches.
The apparatus may comprise a flange. The flange may be configured to be attached to the leg. The flange many be configured to limit the extent to which the leg can be inserted into the foundation pile. Advantageously, the flange can be attached to the leg to define a spacing between an end of the leg and the sea floor within the foundation pile.
The apparatus or flange may comprise a funnel guide. The funnel guide may be arranged to guide, e.g. in use, the rigid tube into the foundation pile.
The funnel guide may comprise a conical portion. The conical portion may be configured, in use, to be located on or proximate an open end of a foundation pile. The funnel guide or conical portion may be configured to guide the rigid tube into the foundation pile.
The flange may be a radially-extending flange. The flange may be configured to engage with, or be positioned on, an open end of a foundation pile. The flange may have one or more apertures extending therethrough, e.g. for locating the rigid tube, in use, relative to a foundation pile. The or each aperture may have a conical portion extending therefrom or thereabout, e.g. to guide the rigid tube towards the respective aperture.
The flange may comprise three apertures circumferentially spaced, e.g. equally spaced, thereabout. The apertures may be configured, in use, to position the rigid tube at circumferential positions relative to the foundation pile. The flange may comprise apertures spaced 45, 90, 120 or 180 degrees apart.
According to another aspect of the invention, there is provided an offshore structure foundation building system, comprising an apparatus as described above, an offshore structure having a leg, and a foundation pile.
Preferably, the leg has no integrated means for conveying grout into the foundation pile. In particular, there is preferably no conduit integrated into the offshore structure or foundation pile.
According to another aspect of the invention, there is provided a kit of parts comprising a rigid tube as described above and a flexible conduit or hose as described above.
The kit of parts may comprise a source of grout, for example a pump unit or grout pump. Additionally or alternatively, the source of grout may comprise a hopper or other storage tank for grout.
According to another aspect of the invention, there is provided a method of fixing an offshore structure to a sub-sea foundation pile, wherein the foundation pile comprises a tube piled into the sea floor and the offshore structure comprises a leg inserted into the foundation pile, wherein the method comprises lowering a rigid tube into a region, e.g. an annular region, described between the foundation pile and the leg such than an outlet of the rigid tube is at a first position, and applying grout to a first region between an end of the leg and the sea floor within the foundation pile via the rigid tube.
The foundation pile may be a pre-piled foundation pile. The leg of the offshore structure may not comprise any internal and/or integrated means for conveying grout into the tubular sub-sea foundation pile.
The rigid tube may be inserted into the region, e.g. annular region, such that when in the first position, it rests on the sea floor within the foundation pile. The rigid tube may be inserted into the region such that when in the first position, the closed end is on contact with or rests on the sea floor. The rigid tube may be inserted into the region such that when in the first position, the closed end lies proximate or adjacent the sea floor.
After grout is applied to the first region, the method may comprise raising the rigid tube such that the outlet is at a second position, above the first position. The method may comprise supplying grout to a second region, the second region being an annular region described between the leg and foundation pile.
When the outlet is at the second position, grout may be conveyed until it fills or overflows the foundation pile.
Filling or overflow of grout from the foundation pile may be determined acoustically and/or visually. Filling or overflow of grout from the foundation pile may be determined using a remotely operated vehicle (ROV). Filling or overflow of grout from the foundation pile may be determined using a density gauge or density meter, e.g. an ultrasonic density gauge or meter or nuclear density gauge or meter.
The offshore structure may be configured to support a payload above the surface of water. The payload may be mounted to the offshore structure, e.g. a jacket thereof, after grouting has been completed. The payload may be or may comprise a wind turbine or an oil and gas platform.
The present method may be particularly advantageous in the case that the payload is a wind turbine. In such a case, there may be cyclical side loading applied to the offshore structure, e.g. due to wind and/or operation of the wind turbine. The structural integrity of the foundation, as a result of the present invention, may provide a more reliable structure when subject to such side loading.
Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. For the avoidance of doubt, the terms “may”, “and/or”, “e.g.”, “for example” and any similar term as used herein should be interpreted as non-limiting such that any feature so-described need not be present. Indeed, any combination of optional features is expressly envisaged without departing from the scope of the invention, whether or not these are expressly claimed. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.
Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:
Certain terminology is used in the following description for convenience only and is not limiting. The words ‘right’, ‘left’, ‘lower’, ‘upper’, ‘front’, ‘rear’, ‘upward’, ‘down’ and ‘downward’ designate directions in the drawings to which reference is made and are with respect to the described component when assembled and mounted. The words ‘inner’, ‘inwardly’ and ‘outer’, ‘outwardly’ refer to directions toward and away from, respectively, a designated centreline or a geometric centre of an element being described (e.g. central axis), the particular meaning being readily apparent from the context of the description. In particular, the words “upstream” and “downstream” designate directions which refer to the direction of fluid flow within the pipe.
Further, as used herein, the terms ‘connected’, ‘attached’, ‘coupled’, ‘mounted’ are intended to include direct connections between two members without any other members interposed therebetween, as well as, indirect connections between members in which one or more other members are interposed therebetween. The terminology includes the words specifically mentioned above, derivatives thereof, and words of similar import.
Further, unless otherwise specified, the use of ordinal adjectives, such as, “first”, “second”, “third” etc. merely indicate that different instances of like objects are being referred to and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking or in any other manner.
Referring now to
The offshore structure 1 is secured to the seabed by fixing it to the foundation piles 5, which are hollow steel tubes pre-piled into the seabed in this example. The stab-in portion 3b of each leg 3 is received within an open end 50 of a respective foundation pile 5. A cementitious material, in the form of grout, is used to at least substantially fill the remaining region or volume between the stab-in portion 3b and foundation pile 5 (made up of regions A and B, as shown in
Referring now to
Referring now to
Extending between the flange 30a and end portion 30b is a sidewall 32b. In the present example the stab-in portion 3b includes a plurality of shear keys 33b located along the length of the sidewall 32b, between the flange 30a and end portion 30b. The shear keys 33b are preferably formed by ridges in the surface of the stab-in portion 3b. The shear keys 33b are configured to provide resistance to relative translational movement between the stab-in portion 3b and the foundation pile 5 after the leg 3 has been grouted to the foundation pile 5, to provide a better fixing of the leg 3 to the foundation pile 5.
Referring now to
In some examples, an underside of the flange 30a has a circumferentially extending seal 34b, in the form of an elastomeric O-ring configured to seal against the free-end 50 of foundation pile 5. Radially inward of the circumferentially extending seal 34b is the overflow outlet 35b, described above. The flange 30a may also include a further aperture, in form of inlet 31a for receipt of the stinger 7, or rigid tube 71 thereof (as shown in
With the stab-in 3b located within the foundation pile 5, a region A is described between the end portion 30b and the dredge line D within the foundation pile 5. Additionally, an annular region B is described between the sidewall 32b and internal wall 51 of the foundation pile 5. During a grouting process (described below) grout is provided to region A and region B. When region A and region B are full grout will overflow the annular region B through outlet 35b. The seal 34b is configured to prevent the leakage of grout from points or areas other than the outlet 35b.
It will be appreciated that, in the present example, in the case of a jacket 2 having a plurality of legs 3, each will have an arrangement as per
To secure the leg 3 to the foundation pile 5 the sea floor is preferably dredged prior to installing foundation piles 5. Then, one or more foundation piles 5 are piled into the sea floor to a desired depth and such that an open end 50 of each pile 5 protrudes from the sea floor. The jacket 2 is then lowered towards the sea floor and respective stab-in portions 3b are located within open ends 50 of respective foundation piles 5. The jacket 2 is lowered until each flange 30a braces against a respective open end 50, describing regions A and B. Grout is then applied to the regions A and B, as described below.
Referring now to
As shown most clearly in
As shown in
Indicia or markings 73 are provided along the length of the rigid tube 71, on an external surface of the sidewall 712. In the present example, the indicia or markings 73 specify the distance from the centre of the outlet 72 to discrete points along the length of the rigid tube 71. Such indicia 73 provide an indication of the depth to which the outlet 72 is inserted into the volume between the stab-in portion 3b and foundation pile 5.
Alternatively, the indicia 73 may specify the distance from closed end 711 to discrete points along the length of the rigid tube 71.
A grouting operation using the apparatus of
In a first stage, the stinger 7 is lowered to a first position P1 as shown by the broken outline in
In the present example, once region A is full, the stinger 7 is then raised by the crane C and the grout filling region A is left to cure to a predetermined degree. The degree of curing may be determined based on the water temperature and a known curing rate of the grout. The grout applied to region A may be left to cure until firm or hard, or substantially firm or hard. The grout applied to region A may be left to cure until it reaches its final set.
The stinger 7 may be raised to a second position P2, as shown by the solid outline in
After the grout filled region A has cured to the predetermined degree the stinger 7 is moved to the second position P2.
Then, with the stinger 7 in the second position P2, grout is conveyed, using the pump unit P, along the stinger 7 to the outlet 72 to fill region B. Grout is conveyed until region B is filled.
In the present example, the filling of region B is identified by the presence of grout at overflow outlet 35b. However, it will be appreciated that instead of providing an overflow outlet 35b, the filling of region B may be determined using a density meter or density gauge, or acoustically, for example by an acoustic sensor on a remotely operated vehicle (ROV), or on the leg 3. Alternatively, filling of region B may be determined by using a pressure sensor or transducer located either on the stinger 7 or within the volume described by regions A and B. In such a case, in the absence of overflow outlet 35b (or with a restricted overflow outlet 35b), once region B is full a pressure increase may be detected if the pump unit P remains activated. In other examples, a predetermined volume of grout is conveyed into the region B based on the known dimensions of the stab-in portion 3b and the foundation pile 5. Such an example might be advantageous where no flange 30a is provided, to prevent overflow of the grout.
Referring now to
In examples, the funnel guide 8 may be formed integrally with the flange 30a.
In use, the funnel guide 8 is used to provide a larger target area for the stinger 7, in particular the rigid tube 71 thereof. This helps locate the stinger 7 with the inlet 31a when it is lowered towards the seafloor.
It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention.
It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20183547.7 | Jul 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/039339 | 6/28/2021 | WO |
