DK181036B1

DK181036B1 - Jackup rig for offshore fish farming

Info

Publication number: DK181036B1
Application number: DKPA201901134A
Authority: DK
Inventors: Melling Dag-Øyvind
Original assignee: Roxel Aqua As
Priority date: 2017-04-10
Filing date: 2019-09-30
Publication date: 2022-10-10
Also published as: GB2574777A; NO20171544A1; CL2019002830A1; GB201914041D0; DK201901134A1; NO344729B1

Abstract

A jackup rig (1) on which a first equipment package (10) comprising a cantilever with a derrick has been replaced with a second equipment package (20) comprising a plant for operating a marine fish farm, the second equipment package (20) being modular and transferable.

Description

DK 181036 B1 1

JACKUP RIG FOR OFFSHORE FISH FARMING The invention relates to the use of a jackup rig for use in fish farming. The invention relates, more particularly, to a jackup rig on which a displaceable cantilever with a prior-art derrick has been replaced with an equipment package comprising a plant for the operation of a marine fish farm.

Background of the invention From the marine petroleum industry, the use of a jackable platform, technically re- ferred to as a jackup rig, is known. A jackup rig comprises a floating hull with a rig floor and several legs that can be moved up or down relative to the hull. By raising the legs, the jackup rig can be moved by means of a tugboat. In a position of application, the legs are lowered to a seabed. When the legs have been anchored to the seabed, the hull may be raised clear of a water surface. For use in the petroleum industry, the jackup rigs are typically provided with a cantilever including a derrick. The jackup rigs may also include a deck arranged on the outside of the hull, technically referred to as a Texas deck.

Because jackup rigs can be moved and can be docked at a quay, they may be altered constructionally at a quay, to be adapted for alternative operations. It is desirable for a possibly constructionally altered jackup rig to be restorable to an ordinary petroleum rig in the easiest way possible.

There is a need in the aquaculture industry to develop fish farms that can be posi- tioned in more weather-exposed localities than the localities that have been in use up to now. There is also a wish to position such localities in the open sea offshore, as, there, there are, among other things, more space than inshore, good current condi- tions and less infection pressure from pathogenic organisms.

, DK 181036 B1 Exposed localities are subjected to larger waves and more wind than the more shield- ed localities inshore. There is a need to develop equipment for fish farming that can resist a storm and large waves without the equipment being damaged. Known jackup rigs are dimensioned for, and certified for, operation in the open sea. Used jackup rigs may be a reasonable alternative to building ocean cages that are only intended for fish farming. Patent US 5628279 discloses how closed and abandoned offshore oil rigs may be con- verted to purposes of aquaculture. A feeding station including a feed silo and other necessary equipment is placed within a standard container.

410 The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features that are specified in the description below and in the claims that follow. The invention is defined by the independent claims. The dependent claims define ad- 145 vantageous embodiments of the invention.

Description of the invention A jackup rig according to the invention has the advantage of being positionable in an exposed locality inshore and offshore. When the cantilever module has been removed, a jackup rig has much space for equipment necessary for operating a fish farm. Such necessary equipment comprises silos for storing fish feed, feeding equipment, equip- ment for treating fish by disease and parasitic attacks, and equipment for collecting and storing dead fish. Further, a jackup rig like that has living rooms for a crew and good possibilities of transporting the crew back and forth, either by helicopter or by boat.

The jackup rig includes space and facilities for large feed stocks, fresh water and living quarters. Existing supporting systems and safety systems on the jackup rig may fur- ther be used; among them, certification in accordance with maritime regulations.

The jackup rig stands firmly on the seabed with its displaceable legs. The jackup rig is therefore a steady rig, and vessels may come alongside the jackup rig to transfer feed, supplies, fish and crew. Correspondingly, fish may be transferred from the jack- up rig to a vessel.

2 DK 181036 B1 The jackup rig according to the invention further has the advantage of making it pos- sible for the rig, when bad weather is forecast, to be raised to increase the so-called air gap between the water surface and the hull of the jackup rig. The rig and the equipment on the rig will thereby not be subjected to waves. The jackup rig as such is dimensioned to withstand bad weather. Farming cages of a type known per se are positioned around the jackup rig. The farm- ing cages may be moored in a manner known per se with individual anchoring sys- tems, or with an anchoring system comprising two or more cages. In one embodi- ment, the cages may be lowerable in a water column. This has the advantage of the cages being lowerable when bad weather is forecast. Exposure of the cages to large waves with a risk of the cages being destroyed is thereby avoided. The cages may be raised in the water column again when the bad weather is over. The cages may be supplied with feed from a feeding system of the fish-farming equipment package of the jackup rig. Such a feeding system is known in the art and will not be described.

45 In a first aspect, the invention relates, more specifically, to a jackup rig where the jackup rig is arranged in a first operative position to comprise a first replaceable equipment package comprising a cantilever with a derrick. The jackup rig is in a sec- ond operative position arranged to comprise a second replaceable equipment package comprising a plant for operating a marine fish farm, the second equipment package is placed on a supporting device, the second equipment package is arranged for posi- tioning on a rig floor on the jackup rig such that the second equipment package re- places the first replaceable equipment package, the second equipment package com- prises at least one silo for feed and a feeding system, and the jackup rig is arranged to optionally be in the first operative position and the second operative position such that the jackup rig in operation houses one of the first or second equipment package.

The effect of the replaceable equipment packages is that the jackup rig may alternate in a quick and easy way between a conventional petroleum rig and a rig for fish farm- ing. The constructional altering of petroleum rigs into fish farms is known, but the constructional alteration is permanent and is done on the rig. This leads to a long and expensive adaptation time. The invention that is described herein makes it possible to complete the second equipment package on shore in order then to replace the cantile- ver with the second equipment package in a quick and efficient manner. By the second equipment package being replaceable, it can be moved from a first rig to a second rig. Such a movement is, in practice, not possible when using the prior art, in which the constructional alteration is permanent.

DK 181036 B1 4 The second equipment package may comprise a control module. Said feed store, feed- ing system and control module may be modules that are used on a conventional feed barge. The second equipment package may thereby be built from known modules. The second equipment package may be placed on a frame or the supporting device arranged to be moved by means of a trolley. In an alternative embodiment, the sec- ond equipment package may be arranged to be moved with a crane. The frame or the supporting device may be of a modular structure so that parts of the second equip- ment package can be replaced independently of each other. The second equipment package may comprise a superstructure, comprising a feed — store and a control module in accordance with the prior art. A modular structure and the use of known components may contribute to a shorter and simpler rebuilding and thereby give a cost-effective construction. Parts of the second equipment package may be replaced independently of each other. The second equipment and the rig may thereby, in a simple manner, be adapted for — possible changes in the operation. The replacement may take place when the jackup rig is alongside quay or when it is in an operative position in the sea. The parts may be replaced by the use of a crane arranged on the jackup rig. The parts may, for ex- ample, be shipped out by the use of a supply vessel. The parts may comprise replaceable feed stores, for example a feed container. Filled feed containers may be carried to the jackup rig by the use of a boat. The empty feed container is lifted off the jackup rig onto the boat, whereas the filled feed container is lifted from the boat onto the jackup rig. Large amounts of feed can thereby be sup- plied in a quick and safe manner. The jackup rig may include at least one additional module provided with at least a — fish-treating unit for the treatment of fish, wherein the at least one additional module may be arranged on the outside of the hull of the jackup rig. The jackup rig may include at least one additional module provided with a feed dis- tributor for distributing feed to a farming cage, wherein the at least one additional module may be arranged on the outside of the hull of the jackup rig.

The at least one additional module may be arranged on a prior-art platform used on jackup rigs. Said platform is known in the trade as a Texas deck. The at least one ad- ditional module may be specially adapted for the purpose. The additional module may

DK 181036 B1 include support functions for a floating treatment unit, for example a pump, a heat- exchanger or a fresh-water intake.

The hull of the jackup rig and the additional module may be connected by at least one telescopic pipe or at least one flexible hose. The additional module may be a support 5 for a flexible fluid-carrying pipe extending from the second equipment package to the floating treatment unit or a cage. The additional module may comprise one feed dis- tributor.

The additional module may include a level control to keep the additional module at a constant height above the water surface.

— The effect of keeping the additional module at a constant height above the water sur- face is that any hoses and pipes running from the additional module into the water may have a constant load and stretch. Further, having a constant height may be ad- vantageous if the additional module is to be used as a landing stage for a boat or a barge.

145 The level control may, for example, be a hydraulic hoisting device or a pitch rack with a spur gear in accordance with the prior art. The additional module may include an automatic vertical level control arranged to keep the additional module at a constant height above the water surface depending on the wave height and tide height.

The jackup rig may comprise a floating treatment unit for fish, wherein, in a position of application, the floating treatment unit is connected to the jackup rig via a flexible fluid-carrying pipe.

The flexible fluid-carrying pipe can transport water from the jackup rig to the floating treatment unit. The water may be heated. The water may be fresh water. The fresh water may have been made on the jackup rig.

— The effect of the floating treatment unit and the flexible fluid-carrying pipe is that the treatment unit may have water supplied from the jackup rig via the flexible fluid- carrying pipe. The floating treatment unit may thereby be made lighter than what is known today, in that it does not have to include means for storing and/or heating wa- ter. The water may be stored in existing reservoirs on the jackup rig. The water may be heated on the rig, in the second equipment package or on the additional module. The water may be pumped from the jackup rig to the floating treatment unit by means of one or more pumps arranged on the rig, in the second equipment package or on the

3 DK 181036 B1 additional module. When fish is being deloused, the infected water may be returned to the jackup rig for cleaning via a return hose.

In a position of application, the flexible fluid-carrying pipe may float in the water. This may lead to a cooling of the water in the pipe. The correct water temperature on the floating treatment unit may be ensured by checking the temperature of the water with sensors arranged at the outlet of the flexible fluid-carrying pipe or at a suitable place on the floating treatment unit. A deviation, if any, from the desired temperature may be compensated for by increasing or reducing the heating on the jackup rig. Said heat control may be manual or automatic.

— The floating treatment unit may include an inlet hose and a return hose for the fish. By using a floating treatment unit as described herein, the treatment tanks may be positioned near the cage and in or near the water surface. The height and the distance over which the fish needs to be moved can thereby be substantially reduced as com- pared with a conventional treatment unit arranged on a boat, for example a well boat.

A low lifting height is further advantageous because it requires less energy and con- tributes to less stress on the fish than a large lifting height.

When not in a position of application, the floating treatment unit may be stored on the jackup rig. The floating treatment unit may be moved between the jackup rig and the water surface by means of a crane and be pulled by a workboat up against the cage, where it is moored. In an alternative embodiment, the floating treatment unit may be provided with a propulsion means of its own. In a further embodiment, the treatment unit may be arranged on a floating vessel, for example a boat or a barge.

Another advantage of the floating treatment unit is that it can replace conventional well boats in the delousing of fish. Conventional well boats are large and expensive in operation. It is also known that the well boats, when positioned against the cage, can easily cause damage to the cage with subsequent escape of fish.

A further advantage of the floating treatment unit is that it is arranged to be stored on the jackup rig. It is thereby easily available, and the reaction time may be reduced if there is a need to treat the fish.

The floating treatment unit may include means for adding medicaments, for example delousing agents and medicines. The floating treatment unit may include a soft side to prevent damage to the cage and the boat. The soft side may be filled with air. The soft side may be padded.

DK 181036 B1 7 In a position of application, at least one flexible fluid-carrying pipe may carry a fluid from the second equipment package to the floating treatment unit or a cage. In a po- sition of application, at least one flexible fluid-carrying pipe may carry a fluid from the additional module to the floating treatment unit or a cage.

The effect of connecting the flexible fluid-carrying pipe as specified herein is getting as direct a transport of the fluid as possible. The flexible fluid-carrying pipe may be con- nected to the additional module and/or be connected to the hull of the jackup rig. The flexible fluid-carrying pipe may distribute water or feed from the second equipment package to the floating treatment unit or the cage. The water may be heated. The — water may be fresh water. A method for changing from a first equipment package to a second equipment pack- age for a jackup rig is described as well, the method comprising the steps: a) bringing the jackup rig alongside a quay; b) moving a first equipment package from the jackup rig to a first position on the quay; c) bringing a second equipment package from a second position on the quay up to the jackup rig; d) moving the second equipment package onto the jackup rig; and e) moving the jackup rig away from the quay. The first equipment package may comprise a cantilever with a derrick. The second equipment package may comprise a plant for operating a marine fish farm. In what follows, an example of a preferred embodiment is described, which is visualized in the accompanying drawings, in which: Figure 1 shows a prior-art jackup rig arranged for petroleum activity; Figure 2 shows a jackup rig according to the invention, modified for marine fish farming; Figure 3 shows the movement of a first equipment package from the jackup rig onto a quay; Figure 4 shows the first equipment package in a first position on the quay and a second equipment package in a second position on the quay; Figure 5 shows the movement of the second equipment package up to the jackup rig;

DK 181036 B1 8 Figure 6 shows the second equipment package positioned on the jackup rig; Figure 7 shows the jackup rig provided with an additional module; Figure 8 shows the movement of the jackup rig away from the quay; Figure 9 shows the jackup rig jacked up into a desired operative position; — Figure 10 shows a plurality of marine farming cages around the jackup rig; Figure 11 shows the additional module provided with a treatment unit for fish in the operative position; Figure 12 shows the jackup rig with an increased air gap in anticipation of bad weather; Figure 13 shows a walkway arranged between the jackup rig and a cage; Figure 14 shows the treatment unit arranged on a boat; and Figure 15 shows the boat shown in figure 14. It should be noted that the drawings basically have different scales.

Figure 1 shows a prior-art jackup rig 1 arranged for petroleum activity, comprising a first equipment package 10 provided with a cantilever module 110 comprising a der- rick, and further comprising a living-quarters module 16, a helicopter pad 17 and a crane 15. Figure 2 shows a jackup rig 1 according to the invention seen from a different angle, where the first equipment package 10 and other petroleum-related equipment (not shown) have been replaced by a second equipment package 20 arranged for fish farming.

As the figures 1 and 2 show, it is only the equipment packages 10, 20 that distinguish the jackup rig 1 in the two highly different fields of application.

The living- quarters module 16, helicopter pad 17 and crane 15 are intact.

Figure 3 shows the jackup rig 1 positioned at a quay 9, where the first equipment package 10 is moved from the jackup rig 1 to a first position 91 on the quay 9 to make room for the second equipment package 20 which, in the figure, is placed in a second position 92. The movement of the first equipment package 10 and the second equipment package 20 is done by the use of a prior-art trolley 3, the trolley 3 being

9 DK 181036 B1 arranged to raise and lower a load. The movement of the first and second equipment packages 10, 20 may alternatively be done with a crane (not shown).

Figure 4 shows the first equipment package 10 placed in the first position 91 on the quay 9. The raisable and lowerable trolley 3 is positioned in front of the second — equipment package 20. In the figure, the second equipment package 20 is shown as one unit comprising a first feed store 21, a second feed store 22, a control room 23 and a prior-art feeding system (not shown). Figure 5 shows the second equipment package 20 placed on the trolley 3 and during movement from the second position 92 on the quay 9 to a rig floor 12 on the jackup rig 1.

Figure 6 shows the second equipment package 20 in an operative position on the jackup rig 1. The second equipment package 20 is lowered onto a plurality of prior-art supports (not shown) arranged on the rig floor 12 of the jackup rig 1. The second equipment package 20 comprises a feed store, a feeding system and a control mod- ule. The feed store comprises feed containers, wherein an empty feed container may be replaced with a filled feed container. The figure also shows an additional module 30 belonging to the second equipment package 20.

Figure 7 shows the jackup rig 1 in a raised position and with the additional module 30 placed on the outside of the hull 11 of the jackup rig 1. The additional module 30 in- cludes a displacing device 31 so that the additional module 30 can be raised and low- ered vertically and moved horizontally on the outside of the hull 11 of the jackup rig 1. The displacing device may comprise a rack and pinion. The additional module 30 may be hoisted into place by means of a crane 15 on the jackup rig 1. In the figure, the additional module 30 is shown in a middle position.

Figure 8 shows a finished, constructionally altered jackup rig 1 while towed by two towing boats TB. Before towing, the legs 13 of the jackup rig 1 are raised so that the hull 11 is floating on a water surface 4 and thereby may be towed from the quay to a work position. During towing, the additional module 30 is advantageously raised to an upper position to go clear of the water surface 4.

Figure 9 shows the jackup rig 1 in a jacked-up and operative position, in which por- tions of the legs 13 visibly extend between the hull 11 and the water surface 4. In the operative position, the legs 13 have been displaced down and are resting on a seabed (not shown) so that the jackup rig 1 is standing stably on the seabed. The three legs

DK 181036 B1 10 13 can be moved independently of each other so that the jackup rig 1 may be level even if the seabed has differences in height, as is known in the trade.

Figure 10 shows the jackup rig 1 in an operative position with a plurality of farming cages 40 positioned around the jackup rig 1. The additional module 30 is shown low- ered to a lower operative position.

The cages 40 are anchored to the seabed (not shown) in accordance with the prior art.

The feed is carried from the feed store 21 to the cages 40 by means of the feeding system, not shown.

The feeding system com- prises a plurality of distribution hoses 41 which carry the feed from the jackup rig 1 to the cages 40. Portions of the distribution hoses 41 are submerged and not shown in the figure.

Figure 11 shows the additional module 30 in an operative position near the water sur- face 4, and provided with a treatment unit 31 for delousing fish (not shown) in the farming cage 40. The fish are brought from the farming cage 40 into a treatment unit 31 on the additional module 30 via an inlet hose 32. The position of application of the 145 module 30 near the water surface 4 gives a minimal lifting height for the fish.

A low lifting height is energy efficient and contributes to less stress on the fish during the delousing process.

After the fish has been treated in the treatment unit 31, it is re- turned to the cage 40 via an outlet hose 33. A flexible net wall 42 in the cage 40 sepa- rates the treated and the untreated fish from each other.

In the figure, the untreated fish are in the cage portion 40U, whereas the treated fish are in the cage portion 40T.

A rotary spreader (not shown) for feed is arranged in the cage 40. Figure 12 shows the jackup rig 1 in a raised position in anticipation of bad weather.

By the rig being raised 1, the hull 11 and the additional module 30 avoid being hit by possible high waves.

At the same time, the cages 40 may be lowered below the water — surface 4 for protection (not shown). Figure 13 shows the additional module 30 in the operative position.

A walkway 14 from the rig floor 12 of the jackup rig 1 to the farming cage 40 provides safe move- ment of personnel between the jackup rig 1 and the farming cages 40. The walkway 14 may be positioned by using the crane 15. The walkway 14 may be telescopic to compensate for varying height differences between the water surface 4 and the rig floor 12. Further, the figure shows walkways 44 between the farming cages 40. Figure 14 shows the treatment unit 31 arranged on a boat 35. The treatment unit 31 is connected to the jackup rig 1 via a flexible fluid-carrying pipe 36 arranged to dis- tribute tempered water from the jackup rig 1 to the treatment unit 31. The water is

DK 181036 B1 11 pumped to the treatment unit 31 via pumps arranged on the additional module 30. A second flexible fluid-carrying pipe (not shown) distributes return water to the jackup rig 1, where the return water is cleaned.

The fish is carried from the farming cage 40 to the treatment unit 31 via the inlet hose

32. In the exemplary embodiment shown, the fish is treated in a treatment vessel (not shown) in the treatment unit 31. After the fish has been treated, it is returned to a second cage 42B via the outlet hose 33.

Figure 15 shows an enlarged section of figure 14. By the treatment unit 31 having water supplied from the jackup rig 1 via the flexible fluid-carrying pipe 36, there is no need to store and heat the water in the treatment unit 31. The treatment unit 31 may thereby be made compact and arranged on a small boat 35. The treatment unit 31 is transferable and may, in an alternative embodiment, be arranged on a barge (not shown).

It should be noted that all the above-mentioned embodiments illustrate the invention, 145 but do not limit it, and persons skilled in the art may construct many alternative em- bodiments without departing from the scope of the attached claims. It should be noted that the drawings basically have different scales.

The use of the verb "to comprise" and its different forms does not exclude the pres- ence of elements or steps that are not mentioned in the claims. The indefinite article "a" or "an" before an element does not exclude the presence of several such elements.

The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage.

Claims

DK 181036 B1 12 Patent claim

1. — Jackup rig (1), wherein the jackup rig (1) in a first operational position is arranged to include a first replaceable equipment package (10) comprising a cantilever with a derrick, characterized in that the jackup rig (1) in a second operational position is arranged to include a second replaceable equipment package (20) which includes a plant for operating a sea pond farm, the second equipment package (20) is placed on a support device, the second equipment package (20) is arranged for positioning on a rig floor (12) of the jackup rig (1) so that the second equipment package (20) replaces the first exchangeable equipment package (10), the second equipment package (18) (20) comprises at least one silo for feed and a feeding system, and the jackup rig (1) is arranged to possibly be in the first operative position and the second operative position, so that the jackup rig {1} in operation contains one of the first or the second equipment package (10, 20).

2. Jackup rig (1) according to claim 1, where an additional module {30} is arranged on the outside of the hull (11) of the jackup rig (1), and the additional module {30} comprises one of a means for treatment of fish and a means of distributing feed to a rearing cage (40).