(19)
(11)EP 3 168 370 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
29.04.2020 Bulletin 2020/18

(21)Application number: 14897054.4

(22)Date of filing:  10.07.2014
(51)International Patent Classification (IPC): 
E02D 27/42(2006.01)
E02D 27/52(2006.01)
G01S 19/14(2010.01)
E02B 17/00(2006.01)
E02B 17/02(2006.01)
G01S 19/01(2010.01)
G01S 19/43(2010.01)
(86)International application number:
PCT/ES2014/070566
(87)International publication number:
WO 2016/005617 (14.01.2016 Gazette  2016/02)

(54)

AUTONOMOUS ANCHORING METHOD AND SYSTEM FOR FOUNDATIONS OF OFFSHORE STRUCTURES

AUTONOMES VERANKERUNGSVERFAHREN UND SYSTEM FÜR FUNDAMENTE VON OFFSHORE-STRUKTUREN

PROCÉDÉ ET SYSTÈME D'ANCRAGE AUTONOME POUR FONDATIONS DE STRUCTURES OFFSHORE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
17.05.2017 Bulletin 2017/20

(73)Proprietor: Drace Infraestructuras S.A.
28050 Madrid (ES)

(72)Inventors:
  • POLIMÓN OLABARRIETA, Carlos Jesús
    E-28050 Madrid (ES)
  • EGUIAGARAY GARCIA, Miguel
    E-28050 Madrid (ES)
  • MOLINA SANCHEZ, Rafael
    E-28050 Madrid (ES)
  • CABRERIZO MORALES, Miguel Angel
    E-28050 Madrid (ES)
  • RODRIGUEZ MORENO, Alberto
    E-28050 Madrid (ES)

(74)Representative: Urizar Anasagasti, Jesus Maria 
IPAMARK, S.L. Paseo de la Castellana 72 1°
28046 Madrid
28046 Madrid (ES)


(56)References cited: : 
GB-A- 2 233 373
US-B1- 6 347 910
US-A1- 2011 013 989
  
  • DATABASE WPI Week 201330, Derwent Publications Ltd., London, GB; Class Q42, AN 2013-G21288, XP055356199 'PROCESS FOR INSTALLING SELF-MOUNTABLE CRANE TOWER FOR SUPPORTING WIND TURBINE IN RENEWABLE OR GREEN ENERGY INDUSTRY, INVOLVES PLACING FOUNDATION BLOCK OR STARTING UNIT IN BODY OF WATER IN WHICH INSTALLATION POINT OF SUBSTRUCTURE IS LOCATED' & ES 2 415 058 A2 (INNEO TORRES SL ET AL.) 23 July 2013
  • DATABASE WPI Week 201374, Derwent Publications Ltd., London, GB; Class Q42, AN 2013-S67841, XP055356207 & WO 2013 157958 A1 (AIBEL) 24 October 2013
  • DATABASE WPI Week 201127, Derwent Publications Ltd., London, GB; Class Q42, AN 2011-D78568, XP055356210 & EP 2 309 063 A1 (AKER JACKET TECHNOLOGY AS) 13 April 2011
  • DATABASE WPI Week 200342, Derwent Publications Ltd., London, GB; Class Q24, AN 2003-442790, XP055356211 & WO 2004 087494 A2 (LOGIMA V SVEND ERIK HANSEN ET AL.) 14 October 2004
  • DATABASE WPI Week 201144, Derwent Publications Ltd., London, GB; Class Q42, AN 2011-H46165, XP055356225 & US 2011 158751 A1 (OHKUBO TAKAHITO ET AL.) 30 June 2011
  • DATABASE WPI Week 201249, Derwent Publications Ltd., London, GB; Class A93, AN 2012-J24290, XP055356259 & US 2012 183359 A1 (NORDSTROM CHARLES J ET AL.) 19 July 2012
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

Object of the invention



[0001] The present invention relates to a method for the autonomous anchoring of foundations for offshore structures, which allows automatic control of the positioning of the structure by means of a system using sensor, control and communication modules.

State of the art



[0002] Gravity foundations of offshore structures can be subdivided into two groups, which are distinguished by the way in which they are transported to their final emplacement, i.e., floating and non-floating foundations. Floating foundations differ from non-floating foundations in that they have the capacity of being towed, thus reducing the costs involved in this stage of the project. Currently, both types of foundations require special means, with a great capacity for load handling, in order to carry out their anchoring and final positioning. In other words, they are not autonomous in their functional transition between floating element, during the transport stage, and gravity foundation, during the service stage.

[0003] Within the framework of floating gravity foundations, there is a subtype composed of a watertight concrete caisson on which the emerged superstructure is arranged, which will serve as a support for the industrial activity (wind turbines, meteorological towers, etc.). The concrete caisson is lightened with rectangular or circular internal cells interconnected with each other. The cells are equipped with filling and emptying devices, enabling ballast control for final anchorage. For example, document ES 2 452 933 describes a gravity foundation for offshore wind turbines based on the use of three hollow and reinforced concrete bases that incorporate a valve system for filling and emptying the water inside it as ballast. These three concrete bases are joined by means of a metal structure in the shape of a tripod having sufficient height to emerge from the free surface of the water. The tower of the wind turbine will be connected to this metal structure by means of an extension piece of the shaft, located above sea level, and in which the berthing area, the stairs and the maintenance platform are installed.

[0004] Within the port community, anchoring operations of partially-emerged concrete caissons are a well-known and commonly used maritime operation in the construction of seawalls. This involves the monitoring of a large number of climatic and operational variables as well as the response of the floating element itself. Four fundamental elements are involved: the floating gravity foundation to be anchored, tugboats, a positioning network and a coordinate reference system external to the element. These anchoring operations are aimed at positioning the structure with level tolerances of between 25 and 50 cm.

[0005] The control of this positioning is usually carried out by fixing the caisson to fixed points such as previously anchored structures or mooring points in other structures and using auxiliary vessels (tugboats), which, anchored to the seabed, take action by means of pulling elements in order to direct the positioning. The different stages of the anchoring operation are carried out by means of the ballasting of the internal cells and the consequent progressive reduction of the freeboard. When the caisson reaches the seabed, its final position is verified and all the cells are filled until the foundation is totally installed on the seabed, leaving the caisson partially emerged in its final location.

[0006] The subtype composed of a watertight concrete caisson could become fully functional if it were given self-anchoring capacity, or autonomy in the process of transition between floating element and gravity foundation. Thus, the final commissioning process, at its final emplacement, would not require the use of special maritime means, which have high mobilization costs and limited availability in the shipping sector.

[0007] The problem that arises when it comes to anchoring foundations for offshore structures, which have to be completely submerged several meters below sea level consists in being able to control the final stage of anchoring, i.e., from the moment the caisson is totally submerged until it smoothly settles in its final location without having to place people on top of the caisson in order to control the maneuver and without using cranes or similar means for supporting the caisson throughout the progress of the proceedings, since it is a self-anchoring process.

[0008] Document WO 0134977 (EP 1 228 310) describes a procedure for the installation of a marine wind turbine, which is fixed to a base that constitutes, together with the shaft, a ballast tank that fills with water until it is anchored to the seabed, being able to float and support the weight in the water when the ballast tank is empty. The transport of the wind turbine to the place of installation is carried out by means of a vessel, because, unlike the caisson of the present invention, in principle it does not float, and if it did, it would not have the stability necessary to be kept in vertical position and be towed from the shore to the place of installation. This document does not describe the way anchoring operations are carried out, but it is assumed that they are carried out with the help of a crane, since if the apparatus as a whole does not have the stability necessary to stay afloat, the only way to control the exact place of installation is by using this type of auxiliary means.

[0009] US2011013989 discloses a loading and unloading system, which includes a liquid storage apparatus, which is used as an offshore terminal under water or on the surface of the water and can be applied with offshore oil drilling and production facilities. This system includes a storage tank comprising at least one water ballast compartment and at least one oil storage compartment and one volume of inert gas, in which the water ballast compartment and oil storage compartments are coupled to each other to form a closed interconnected system with pressurized inert gas above water and oil, by means of valves that allow the connection of fluid between the water ballast compartment and the oil storage compartment, as a result of which the two compartments are not permanently connected. In another embodiment, this system comprises pumps coupled to the storage tank, loading and unloading oil in the corresponding compartment and for loading and unloading water from the water ballast compartment. No precision is required in the displacement of this tank sunk in the sea, since it rarely gets to be deposited on the seabed and when it is done it nothing from the invention shows that it is needed any requirement with respect to the precision in the sea anchoring.

[0010] GB2233373 discloses a method and means for positioning structures on the seabed, in which part of the operations imply the postioning, e.g., of a lower structures such as a drawer/box for a foundation of a platform for drilling or prospecting hydrocarbons, whereby the drawer/box, that is large and heavy will be placed on or adjacent to a structure already placed on the seabed, for example, a well template, The drawer, which will be placed, can easily damage the structure already placed, and the positioning should therefore be carried out with utmost care and with great precision. This method provides for the placement of an anchorage for the structure, located on the seabed at the place intended for the assembly of said structure to guarantee its position, while sinking from a floating position to a predetermined level on the seabed, where the equipment suitable on the structure enters pivoting coupling with the locking platform. By using suitable means the structure pivots on the locking basis until the structure correctly reaches the correct azimuth position. The pivoting movement is controlled by suitable means of monitoring and slowing down located on the lower side of the structure, which means contact and partial penetration into the seabed while the structure is positioned cuts distance on the bottom of the sea and therefore provides the desirable friction and control of said pivoting movements; finally the structure sinks into the seabed in the correct position.

Description of the invention



[0011] The present invention describes a method, as defined by claim 1, and a system, as defined by claim 5, for achieving the self-anchoring of floating dock-type foundations, capable of being towed to their final location, which consist of a self-floating concrete caisson, provided with internal vertical cells, closed at the top by means of a slab that covers all or almost all the cells in which it is divided, which are interconnected with each other and equipped with emptying and filling devices that allow the regulation of the ballast level for anchoring when they are filled with seawater, obtaining a margin of precision equivalent to that of other floating caissons used in the construction of docks that remain partially emerged, although in this case the foundation is totally submerged several meters below sea level.

[0012] Once the foundation has been towed to a place next to that of its installation, anchored and totally submerged, the method of anchoring comprises the following stages:
  1. a) Constraining the foundation, which includes fastening and mooring by at least three tugboats pulling radially from at least 3 different directions, spaced apart at a similar angle, so that once the foundation is vertically located on its final installation site, it is kept in the same vertical position throughout the entire anchoring process.
  2. b) The next stage comprises the connection of the entire anchoring system, which includes: connecting the different sensors needed for controlling the operation with a control unit receiving information therefrom. This unit is preferably located on the emerged platform of the foundation that remains above sea level once the foundation has been totally anchored. Said unit integrates means of communication with the directional system between the tugboats, and means of communication between the GPS stations and a fixed GPS reference base located at a fixed point next to the installation location of the foundation. This control unit will also be associated to decision-making support equipment, which enables an operator to visualize and control the anchoring process as well as modify parameters of the process or detain it in the event of failure.
  3. c) Once the necessary means of control have been installed, the gradual and controlled sinking of the foundation is begun until it is slowly submerged. The critical point of this process occurs when the foundation remains in balanced position under the water. From this point on, the anchoring is continued until it gently reaches its position of installation on the seabed.
  4. d) When the foundation is placed on the seabed, its final ballasting takes place, flooding all the cells which incorporates the foundation and subsequently the tugboat lines are disengaged, concluding the operation.


[0013] The sinking process of the cells is gradual and is carried out in groups of cells that are next to each other, in a controlled manner, either through control software or manually, using the greater or lesser filling of an area or areas of the foundation in order to achieve tilting and, in this way, displacement or rotation in a determined direction. The foundation can also be moved or rotated slightly until relocating it vertically at its final installation site through the tension of the tug lines of the different tugboats. These operations are carried out at any time during the anchoring process, regardless of the position of the foundation, even when it is totally submerged, while it has not reached the position of its final emplacement.

[0014] Anchoring speed can be modified by varying the filling rate of the cells of the foundation with seawater.

[0015] Despite the random nature of the factors involved in the anchoring method, this system is autonomous to the extent that it is capable of making decisions in a systematic way, thus providing repeatability. This way, the floating object is capable of managing its own commissioning and, therefore, necessary maritime resources, such as anchoring support, are minimal and installation costs are also lower.

[0016] The system also provides reliability to foundation installation operations through the definition of quality parameters (operational threshold values) that the system itself ensures are not exceeded. This is the very reason it is an autonomous system that does not need the support of high-level maritime resources. The floating object itself can behave like a vessel.

[0017] Dynamic float control is required during the different stages of anchoring described previously in order to provide the foundation with self-anchoring capacity supervised by an expert operator. To this end, operation security and reliability criteria are fixed in terms of operational thresholds. The variables that define the reliability and the security of the operation are:
  • the heel and/or maximum trim of the structure during each anchoring stage.
  • the speed and/or maximum admissible acceleration of the same, or of the elements carried on the superstructure.


[0018] Similarly, the final installation process of the structure must be carried out minimizing the probability of impacts of the structure with the seabed and facilitating the final positioning according to project tolerances.

[0019] The proposed solution for the anchoring system consists of a system made up of 4 subsystems that allow the autonomous anchoring of floating gravity foundations and their positioning on the seabed:
  • An assembly of sensors that measure different variables in the foundation.
  • A control unit which receives the signals from the sensors on the position of the foundation and controls the valves and other means of filling the floating caisson, as well as the corrections that these have to make and the tugboats.
  • Means of communication between the different pieces of equipment.
  • User interface for decision-making support and the execution of different control instructions to said control unit.


[0020] The different sensors fulfill the following functions through the elements that make them up:
  • Measuring the level of ballast in cell groups: level sensors.
  • Measuring interior air pressure in the cells: pressure sensors.
  • Measuring the rotations that take place: a gyroscope.
  • Determining the absolute position of the structure: positioning sensor.
  • Determining the relative position of the structure with respect to the installation surface of the same: pressure sensors and positioning sensors.
  • Measuring the vertical heave and the inertial response: heave sensor.
  • Recording the accelerations and rates that structural elements undergo: accelerometer.
  • Detecting contact of the structure with the seabed, as well as possible impacts on other structures: accelerometer and gyroscope.
  • Measuring local conditions of marine environment forcing (measuring sea level, surge and currents): Surface (or underwater) Doppler Acoustic sensor.


[0021] The control equipment directs and regulates the following variables through the elements which integrate it:
  • Input and output of the liquid ballast in groups of cells, ballast and deballast valves, as well as submersible de-ballasting pumps and ballast level sensors.
  • Interior pressure in the cells: vent valves.
  • Horizontal position of the structure (on a ground plan): winches of the tugboats.
  • Dynamic control or trim and heel (rotations): filling valves.
  • Dynamic control of the installation of the structure on the seabed: filling valves.
  • Relative position with respect to the installation surface of the same (distance to the seabed): filling valves
  • Vertical heave and its inertial response.
  • Inertial response of the structural elements that it may transport or carry: accelerometer and gyroscope.
  • Possible impacts on other structures, marine environments or the seabed: Accelerometer and gyroscope.
  • Contact of the structure with the seabed: Accelerometer and gyroscope.
  • Actuator control unit.


[0022] The system incorporates several means of communication:
  • Receiver unit for sensor information located on the emerged platform of the foundation.
  • Wireless directional system (Wi-Fi) between the vessels intended as control centers and the receiver and control unit for information from the sensors located on the foundation.
  • UHF communication system between GPS stations and the GPS-RTK base (fixed reference point).
  • Communication system between the sensoring and control units.


[0023] The user interface that serves as decision-making support consists of the following elements:
  • Visualization of sensory variables and control (status).
  • Pre-programming of the sequence of operations (opening valves and voltages in the winches of the vessels) and of the operational thresholds by stages of anchoring, which act as indicators of the quality of the operation (admissible angles of heel and trim, sink speed of the gravity foundation, acceleration in the elements that make up the superstructure).
  • Visualization of the progress of each of the operational status variables recorded by the sensoring and control subsystem during the stages of anchoring: submerging, anchoring, contact, installation on the seabed, installation and final ballasting.
  • Offset (zeros of the reference system of the sensoring and control subsystem).
  • Automatic correction of thresholds.
  • Manual intervention in the operation.
  • List of automatic actions and those derived from manual intervention.
  • Instrumental alarm for exceedances of operational thresholds and system operations status.
  • Cross check for the start of a new stage or restart after operational shutdowns.


[0024] The system logically incorporates power supply units (3) consisting of an electric energy generating system and a compressor.

[0025] The novelties of this system for anchoring are:
  • Autonomy in the development of the operation since it enables anchoring in a totally automatic way, allowing potential human intervention if necessary.
  • It is reliable since it controls and limits the exceedances of operational thresholds in an autonomous way.
  • It allows the visualization of the status of the parameters that define the anchoring operation in real time and at all times.
  • It allows the control of all the processes involved in the operation in real time.
  • The interface shows the processes of the installation with the status and situation of the elements, so that the operator receives feedback-guaranteeing functionality.
  • The system is conceived such that it enables anchoring in a totally automatic way, with minimum human intervention, and only if needed.
  • It does not require the use of either heavylift or singular vessels for the installation.

Description of the drawings



[0026] In order to complement the description presented herein, and with the aim of gaining a better understanding of the characteristics of the invention, a set of drawings is attached to this specification, wherein, by way of non-limiting examples, the following has been represented:

Figure 1 shows the tugboat system (2) arranged in a layout for the installation of any given foundation (1).

Figure 2 shows the elements involved in the anchoring system, wherein the following can be distinguished:

  • The foundation to be anchored (1).
  • The tugboats (2).
  • The positioning system (3).
  • The platform or fixed point of reference for the reference system (4).

Figure 3 shows an elevation of a foundation with a structure in whose upper area the wind turbine or the meteorological station will be fixed and on which the most important sensoring and control elements, arranged on the object to be anchored, have been pointed out:

  • Valves (5)
  • Filling level sensors (pressure sensors) (6)
  • Submersible pumps (7)
  • Accelerometer-gyroscope (8)
  • GPS-RTK antennas (9)

Figure 4 shows a general flowchart of the autonomous anchoring system.

Figure 5 offers a schematic representation of the main stages of anchoring operations.


Detailed description of at least one embodiment of the invention



[0027] The proposed system for anchoring integrates its different elements into the equipment comprising the assembly of the same: tugboats (2), foundation to be anchored (1), base platform or fixed point of reference (4) and positioning network (3): see Figure 2).

[0028] The user interface consisting of a command control server or SCADA (Supervisory Control And Data Acquisition) system is installed in the tugboats (2), which system enables remote visualization, monitoring and control of the process. It is a closed loop system, i.e., it adjusts the control through feedback of the output signal. An 8-port switch, two modems for wireless communication and at least two CPUs and auxiliary screens are also installed in the tugboats (2), which enable the visualization of the status of the process variables by means of an interface. This interface has particular tabs for visualizing the position of the element to be installed, filling level of the cells, alarms, electrical parameters, tension in the mooring lines, etc. It also enables visualizing the status of the instrumentation such as the valves (5), pumps (7) and filling (6) and movement (accelerometer-gyroscope) sensors (8).

[0029] The control unit, preferably consisting of a PLC (Programmable Logic Controller) is installed in an electric cabinet on the foundation platform (1) that remains emerged, which in turn communicates with the command control system in the vessels by means of Wi-Fi modems.

[0030] The positioning equipment is be made up of an RTK reference base installed at a fixed reference point (3), a GPS-RTK antenna (9) installed on the foundation platform (1) that remains emerged and the accelerometer-gyroscope (8) also installed on the foundation platform (1).

[0031] The system controls the measurements carried out by the sensoring subsystem, analyzes movement frequencies and filters them so that it can respond to them by setting new reference thresholds. Thus, it becomes independent from external factors: it turns into an autonomous anchoring system.

[0032] The system for autonomous anchoring is susceptible of industrial application in the offshore wind power and civil engineering sectors. While foundation construction may be more or less industrialized for mass production, the process of laying the foundation is largely depends on the capabilities of the operator due to the large number of variables involved in the operations and the uniqueness of the stages of anchoring.

[0033] Figure 5 shows several stages of anchoring operations:
  • Constraint of the foundation, attaching, and connection to tugboats (Figure 5.1)
  • Submerging (Figure 5.2)
  • Sinking (Figure 5.3)
  • Installation on the seabed (Figure 5.4)
  • Final ballasting (Figure 5.5)


[0034] In the stage of constraint of the foundation (1) at least three tugboats (2) are fastened and moored, which pull radially on the foundation to be anchored from at least 3 different directions, spaced apart at a similar angle, so that once it is located vertically on its final installation site, it is kept in the same position throughout the entire anchoring process. See Figure 1.

[0035] Before or after the previous stage, the following connections are carried out:
  • The different sensors needed for controlling the operation.
  • The control unit, located above sea level on the emerged platform of the foundation.
  • The different communication equipment: with the directional system between the tugboats, between the GPS stations and with a fixed GPS reference base located at a fixed point next to the installation location of the foundation.
  • And the implementation of a decision-making support system, which enables visualizing and controlling the progress of the anchoring process.


[0036] Once all the instrumentation is installed and operating, and the tugboats (2) keep the cables that are pulling on the foundation (1) under tension, so that it is floating vertically on the point of the seabed on which it is to be installed, anchoring is carried out by gradually sinking the foundation, the whole process being controlled by the described system, until the foundation is slowly submerged (Figure 5.2), remaining in neutral position below the water. Subsequently, the foundation continues to be anchored in a next to neutral seaworthy condition (Figure 5.3) until it reaches its position of installation on the seabed (Figure 5.4).

[0037] Finally the foundation is ballasted, all the cells contained in the foundation are flooded and the tugboat lines are disengaged (Figure 5.5).


Claims

1. A method for the autonomous anchoring of foundations (1) for offshore structures, built on a floating dock and capable of being towed to their final location, consisting of a self-floating concrete caisson, provided with internal vertical cells, closed at the top by means of a slab that covers all or almost all the cells in which it is divided, which are interconnected with each other and equipped with emptying and filling devices (5, 7) that allow the regulation of the ballast level for anchoring when they are filled with seawater, comprising a preliminary stage:

constraining the foundation, fastening and mooring with at least three tugboats (2) pulling radially on the foundation to be anchored from at least 3 different directions, spaced apart at a similar angle, so that once the foundation is vertically located on its final installation site, it is kept in the same vertical position throughout the entire anchoring process,

characterized in that it also comprises the following stages

a) a preliminary stage of connecting the different sensors (6, 8) needed for controlling the operation with a control unit receiving the information from said sensors, preferably located on the emerged platform of the foundation that remains above sea level once the foundation has been totally anchored, said control unit integrating means of communication with the directional system between the tugboats, and means of communication between the GPS stations (9) and a fixed GPS reference base (4) located at a fixed point next to the installation location of the foundation; as well as the implementation of a decision-making support system, which enables visualizing and controlling the progress of the anchoring process;

b) gradual and controlled sinking of the foundation until it is slowly submerged, remaining in a neutral position under the water and subsequent anchoring of the same in a next to neutral seaworthy condition until it reaches its position of installation on the seabed;

c) final ballasting of the foundation, flooding of all the cells that the foundation incorporates and disengaging the tugboat lines.


 
2. The method, according to the previous claim, characterized in that the filling of the cells of the foundation is carried out gradually, in groups of cells that are next to each other, in a controlled manner, either through control software or manually, using the greater or lesser filing of an area or areas of the foundation to achieve tilting and in
this way controlling the heel and/or maximum trim of the structure during each stage of anchoring.
 
3. The method according to the preceding claims, characterized in that the tension of the tug lines of the different tugboats is controlled in order to cause displacement and thereby control the heel and/or maximum trim of the structure during each stage of anchoring.
 
4. The method according to the preceding claims, characterized in that the speed and maximum acceleration of the sinking of the foundation is controlled by modifying the filling rate of the cells of the foundation with seawater.
 
5. A system for the autonomous anchoring of foundations (1) for offshore structures, which enables automatic controlling of the different stages of the anchoring operation of gravity foundations, powered by an electric energy generating system and a compressor, characterized in that it comprises:

- an assembly of sensors (6, 8) that measure different variables that affect the foundation (1) consisting of a self-floating concrete caisson, enabling to determine the movements, the degree of filling of the cells that make up the foundation, as well as its position with respect to what will be its final anchoring site;

characterized in that it also comprises:

- a control unit which

∘ receives the signals from the sensors and from the caisson's position at all times, which conforms the foundation with respect to the location; -

∘ controls the valves (5) and other means of filling and the necessary corrections of both said means of filling

∘ controls the direction and the tension with which the tugboats (2) pull radially on the foundation to be anchored from at least 3 different directions spaced apart at a similar angle; so that the foundation gradually sinks by itself until it lies on the seabed in its final position of installation;

- means of communication between the different pieces of equipment receiving information from the sensors, from the GPS stations (9) located on the foundation and from a fixed GPS reference station (4) located at a fixed point next to the anchoring site of the foundation, all of them communicating information to the control unit; and

- user interface for decision-making support and the execution of different control instructions to said control unit, including

∘ means for visualizing the variables and the progress of the operation,

∘ software in which sequence programming actions are implemented and

∘ means that enable manual intervention in the operation.


 
6. The system according to claim 5, characterized in that the sensors incorporated in the different units of the system fulfill the following functions:

- measuring the level of ballast in cell groups,

- measuring the interior air pressure in the cells,

- measuring the rotations that take place,

- determining the absolute position of the structure,

- determining the relative position of the structure with respect to the surface on which it is installed,

- measuring the vertical heave and the inertial response,

- recording the accelerations and speed rates that structural elements undergo,

- detecting contact of the structure with the seabed, as well as possible impacts on other structures,

- measuring local conditions of marine environment forcing.


 
7. The system, according to claims 5 and 6, characterized in that the control unit directs and regulates the following variables through the elements that integrate it:

- input and output of the liquid ballast in groups of cells,

- interior pressure in the cells,

- horizontal position of the structure (on a ground plan),

- dynamic control of trim and heel (rotations),

- dynamic control of structure installation on the seabed,

- relative position with respect to the installation surface (distance to the seabed),

- vertical heave and its inertial response,

- inertial response of the structural elements that it may transport or carry,

- possible impacts on other structures, marine environments or the seabed,

- contact of the structure with the seabed.


 
8. The system, according to claims 5 to 7, characterized in that it incorporates the following means of communication:

- a receiver unit for information from the sensors located on the emerged platform of the foundation,

- a wireless intercommunication unit (Wi-Fi) between the vessels intended as control centers and the receiver and control unit for information from the sensors located on the foundation,

- a UHF communication system between GPS stations and the GPS-RTK base (fixed reference point),

- a means of communication between the sensoring and control units.


 
9. The system, according to claims 5 to 8, characterized in that the user interface that serves as decision-making support consists of the following elements:

- means for the visualization of sensory variables and control (status) and of the progress of each of the operational status variables recorded by the sensoring and control subsystem during the stages of anchoring,

- software in which the sequence of operational actions (opening of valves and voltages in the winches of the vessels) and of the operational threshold by stages of anchoring, as well as automatic correction of thresholds are implemented,

- means that enable manual intervention on the operation

- means of warning for exceedances of operational threshold and system operations status,

- a status cross check for starting a new stage or restarting after operational shutdowns.


 


Ansprüche

1. Verfahren zur autonomen Verankerung von Fundamenten (1) für Offshore-Strukturen, die auf einem schwimmenden Dock gebaut und an ihren endgültigen Standort geschleppt werden können, bestehend aus einem selbstschwimmenden Senkkasten aus Beton, der mit inneren vertikalen Zellen bereitgestellt ist, oben mittels einer Platte verschlossen ist, die alle oder fast alle Zellen, in die sie unterteilt ist, bedeckt, die miteinander verbunden sind und mit Entleerungs- und Füllvorrichtungen (5, 7) ausgestattet sind, welche die Regulierung des Ballastniveaus zur Verankerung ermöglichen, wenn sie mit Meerwasser gefüllt sind, umfassend eine Vorstufe: Begrenzen des Fundaments, Befestigen und Festmachen mit mindestens drei Schleppern (2), die radial an dem zu verankernden Fundament aus mindestens 3 verschiedenen Richtungen, die in einem ähnlichen Winkel beabstandet sind, ziehen, sodass das Fundament, sobald es sich vertikal an seinem endgültigen Installationsort befindet, während des gesamten Verankerungsverfahrens in der gleichen vertikalen Position gehalten wird,
dadurch gekennzeichnet, dass es auch die folgenden Stufen umfasst:

a) eine Vorstufe des Verbindens der verschiedenen Sensoren (6, 8), die zum Steuern des Betriebs erforderlich sind, mit einer Steuereinheit, welche die Informationen von den Sensoren empfängt, die sich vorzugsweise auf der aufgetauchten Plattform des Fundaments befindet, die über dem Meeresspiegel verbleibt, wenn das Fundament vollständig verankert ist, wobei die Steuereinheit Kommunikationsmittel mit dem Richtungssystem zwischen den Schleppern und Kommunikationsmittel zwischen den GPS-Stationen (9) und einer festen GPS-Referenzbasis (4) integriert, die sich an einem festen Punkt neben dem Installationsort des Fundaments befindet; sowie die Ausführung eines Entscheidungsunterstützungssystems, das die Visualisierung und Steuerung des Fortschritts des Verankerungsverfahrens ermöglicht;

b) allmähliches und gesteuertes Absenken des Fundaments, bis es langsam untergetaucht ist, wobei es in einer neutralen Position unter dem Wasser verbleibt und anschließend in einem nahezu neutralen seetüchtigen Zustand verankert wird, bis es seine Installationsposition auf dem Meeresboden erreicht;

c) endgültiges Füllen des Fundaments mit Ballast, Fluten aller in das Fundament eingebauten Zellen und Lösen der Schlepperleinen.


 
2. Verfahren nach dem vorhergehenden Anspruch, dadurch gekennzeichnet, dass das Füllen der Zellen des Fundaments allmählich in Gruppen von Zellen, die nebeneinander liegen, in gesteuerter Weise, entweder durch Steuerungssoftware oder manuell, durchgeführt wird, wobei das mehr oder weniger Füllen eines Bereichs oder von Bereichen des Fundaments verwendet wird, um ein Kippen zu erreichen, und auf diese Weise die Krängung und/oder die maximale Längsneigung der Struktur während jeder Stufe der Verankerung zu steuern.
 
3. Verfahren nach den vorhergehenden Ansprüchen, dadurch gekennzeichnet, dass die Spannung der Schleppleinen der verschiedenen Schlepper gesteuert wird, um eine Verlagerung zu bewirken und dadurch die Krängung und/oder die maximale Längsneigung der Struktur während jeder Stufe der Verankerung zu steuern.
 
4. Verfahren nach den vorhergehenden Ansprüchen, dadurch gekennzeichnet, dass die Geschwindigkeit und maximale Beschleunigung des Sinkens des Fundaments durch Modifizieren der Füllgeschwindigkeit der Zellen des Fundaments mit Meerwasser gesteuert wird.
 
5. System zur autonomen Verankerung von Fundamenten (1) für Offshore-Strukturen, das eine automatische Steuerung der verschiedenen Stufen des Verankerungsvorgangs von Schwerkraftfundamenten ermöglicht, angetrieben durch ein elektrisches Energieerzeugungssystem und einen Kompressor, dadurch gekennzeichnet, dass es Folgendes umfasst:

- eine Anordnung von Sensoren (6, 8), die verschiedene Variablen messen, welche das Fundament (1) beeinträchtigen, bestehend aus einem selbstschwimmenden Senkkasten aus Beton, der es ermöglicht, die Bewegungen, den Füllgrad der Zellen, welche das Fundament ausbilden, sowie seine Position in Bezug auf seinen endgültige Verankerungsort zu bestimmen;

dadurch gekennzeichnet, dass sie auch Folgendes umfasst:

- einer Steuereinheit, welche

∘ die Signale von den Sensoren und von der Position des Senkkastens zu jeder Zeit empfängt, die mit dem Fundament in Bezug auf den Standort übereinstimmen;

∘ die Ventile (5) und andere Füllmittel und die nötigen Korrekturen beider Füllmittel steuert;

∘ die Richtung und die Spannung steuert, mit welcher die Schlepper (2) radial an dem zu verankernde Fundament aus mindestens 3 verschiedenen, in einem ähnlichen Winkel beabstandeten Richtungen ziehen, sodass das Fundament allmählich von selbst absinkt, bis es in seiner endgültigen Installationsposition auf dem Meeresboden liegt;

- Kommunikationsmittel zwischen den verschiedenen Vorrichtungen, die Informationen von den Sensoren, von den GPS-Stationen (9), die sich auf dem Fundament befinden, und von einer festen GPS-Bezugsstation (4), die sich an einem festen Punkt neben der Verankerungsstelle des Fundaments befindet, empfangen, wobei alle Informationen an die Steuereinheit übertragen; und

- Bedienerschnittstelle zur Entscheidungsunterstützung und Ausführung verschiedener Steueranweisungen an die Steuereinheit, einschließend

∘ Mittel zur Visualisierung der Variablen und des Fortschritts des Vorgangs,

∘ Software, in der Ablaufprogrammierungs-Aktionen umgesetzt sind und

∘ Mittel, die einen manuellen Eingriff in das Verfahren ermöglichen.


 
6. System nach Anspruch 5, dadurch gekennzeichnet, dass die Sensoren, die in die verschiedenen Einheiten des Systems integriert sind, die folgenden Funktionen erfüllen:

- Messen des Ballastniveaus in Zellgruppen,

- Messen des Innenluftdrucks in den Zellen,

- Messen der Rotationen, die stattfinden,

- Bestimmen der absoluten Position der Struktur,

- Bestimmen der relativen Position der Struktur in Bezug auf die Oberfläche, auf der sie installiert ist,

- Messen der vertikalen Auf- und Abbewegung und der Trägheitsreaktion,

- Aufzeichnen der Beschleunigungen und Geschwindigkeiten, denen Strukturelemente unterliegen,

- Erkennen von Kontakt der Struktur mit dem Meeresboden sowie möglicher Auswirkungen auf andere Strukturen,

- Messen der örtlichen Bedingungen des Einflusses der marinen Umgebung.


 
7. System nach Anspruch 5 und 6, dadurch gekennzeichnet, dass die Steuereinheit die folgenden Variablen durch die Elemente, welche sie integrieren, lenkt und reguliert:

- Ein- und Abgabe des flüssigen Ballasts in Gruppen von Zellen,

- Innendruck in den Zellen,

- horizontale Position der Struktur (in einem Grundriss),

- dynamische Steuerung von Längsneigung und Krängung (Rotationen),

- dynamische Steuerung der Strukturinstallation auf dem Meeresboden,

- relative Position in Bezug auf die Aufstellfläche (Abstand zum Meeresboden),

- vertikale Auf- und Abbewegung und deren Trägheitsreaktion,

- Trägheitsreaktion der Strukturelemente, die es transportieren oder tragen kann,

- mögliche Auswirkungen auf andere Strukturen, marine Umgebungen oder den Meeresboden,

- Kontakt der Struktur mit dem Meeresboden.


 
8. System nach Anspruch 5 bis 7, dadurch gekennzeichnet, dass es die folgenden Kommunikationsmittel aufweist:

- eine Empfängereinheit für Informationen von den Sensoren, die sich auf der aufgetauchten Plattform des Fundaments befinden,

- eine drahtlose Interkommunikationseinheit (Wi-Fi) zwischen den als Steuerzentren vorgesehenen Schiffen und der Empfänger- und Steuereinheit für Informationen von den Sensoren, die sich auf dem Fundament befinden,

- ein UHF-Kommunikationssystem zwischen GPS-Stationen und der GPS-RTK-Basis (fester Referenzpunkt),

- ein Kommunikationsmittel zwischen den Sensor- und Steuereinheiten.


 
9. System nach Anspruch 5 bis 8, dadurch gekennzeichnet, dass die Bedienerschnittstelle, die als Entscheidungsunterstützung dient, aus den folgenden Elementen besteht:

- Mitteln zur Visualisierung der Sensorvariablen und der Steuerung (Zustand) sowie des Fortschritts jeder der Betriebszustandsvariablen, die von dem Sensor- und Steuerungsteilsystem während der Stufen der Verankerung aufgezeichnet werden;

- Software, in welcher der Ablauf der Betriebsaktionen (Öffnen von Ventilen und Spannungen in den Winden der Schiffe) und der Betriebsschwelle nach Stufen der Verankerung sowie die automatische Korrektur von Schwellen umgesetzt werden,

- Mittel, die einen manuellen Eingriff in den Betrieb ermöglichen

- Mittel zur Warnung bei Überschreitungen der Betriebsschwelle und des Betriebszustands des Systems,

- eine Gegenprobe des Zustands zum Starten einer neuen Stufe oder zum Neustarten nach Betriebsabschaltungen.


 


Revendications

1. Procédé pour l'ancrage autonome de fondation (1) pour des structures offshore, construites sur un quai flottant et pouvant être remorquées jusqu'à leur emplacement final, constituées d'un caisson en béton auto-flottant, pourvu de cellules verticales internes, fermé au sommet par une dalle qui recouvre tout ou presque toutes les cellules dans lesquelles il est divisé, qui sont interconnectées entre elles et équipées de dispositifs de vidange et de remplissage (5,7) qui permettent de régler le niveau du ballast pour l'ancrage lorsqu'elles sont remplies d'eau de mer, comprenant une étape préliminaire : contraindre la fondation, fixer et amarrer avec au moins trois remorqueurs (2) tirant radialement sur la fondation à ancrer dans au moins 3 directions différentes, espacées selon un angle similaire, de sorte qu'une fois que la fondation est située verticalement sur son site d'installation finale, elle est maintenue dans la même position verticale tout au long du processus d'ancrage, caractérisé en ce qu'il comprend également les étapes suivantes

a) une étape préliminaire de connexion des différents capteurs (6, 8) nécessaires pour contrôler l'opération avec une unité de contrôle recevant les informations desdits capteurs, située de préférence sur la plateforme émergée de la fondation qui reste au-dessus du niveau de la mer une fois que la fondation a été totalement ancrée, ladite unité de contrôle intégrant des moyens de communication avec le système directionnel entre les remorqueurs, et des moyens de communication entre les stations GPS (9) et une base de référence GPS (4) fixe située à un point fixe proche de l'emplacement de l'installation de la fondation ; ainsi que la mise en place d'un système de support à la prise de décision, qui permet de visualiser et de contrôler l'avancement du processus d'ancrage ;

b) enfoncement progressif et contrôlé de la fondation jusqu'à ce qu'elle soit lentement submergée, restant dans une position neutre sous l'eau et ancrage ultérieur de celle-ci dans un état de navigabilité proche de la neutralité jusqu'à ce qu'elle atteigne sa position d'installation sur le fond marin ;

c) lestage final de la fondation, inondation de toutes les cellules que la fondation incorpore et désengagement des lignes de remorqueurs.


 
2. Procédé, selon la revendication précédente, caractérisé en ce que le remplissage des cellules de la fondation s'effectue progressivement, en groupes de cellules qui sont côte à côte, de manière contrôlée, soit via un logiciel de contrôle, soit manuellement, en utilisant le remplissage plus ou moins important d'une zone ou de zones de la fondation pour obtenir l'inclinaison et ainsi contrôler la gîte et/ou l'assiette maximale de la structure lors de chaque étape d'ancrage.
 
3. Procédé selon les revendications précédentes, caractérisé en ce que la tension des lignes de remorquage des différents remorqueurs est contrôlée afin d'entraîner un déplacement et ainsi contrôler la gîte et/ou l'assiette maximale de la structure lors de chaque étape d'ancrage.
 
4. Procédé selon les revendications précédentes, caractérisé en ce que la vitesse et l'accélération maximale de l'enfoncement de la fondation sont contrôlées en modifiant le taux de remplissage des cellules de la fondation avec de l'eau de mer.
 
5. Système pour l'ancrage autonome de fondations (1) pour des structures offshore, qui permet un contrôle automatique des différentes étapes de l'opération d'ancrage de fondations gravitaires, alimenté par un système de génération d'énergie électrique et un compresseur, caractérisé en ce qu'il comprend :

- un ensemble de capteurs (6, 8) qui mesurent différentes variables qui affectent la fondation (1) constituée d'un caisson en béton auto-flottant, permettant de déterminer les mouvements, le degré de remplissage des cellules qui composent la fondation, ainsi que sa position par rapport à ce qui sera son site d'ancrage définitif ; caractérisé en ce qu'il comprend également :

- une unité de contrôle qui

∘ reçoit à tout moment les signaux des capteurs et de la position du caisson, qui conforme la fondation par rapport à l'emplacement ; -

∘ contrôle les vannes (5) et les autres moyens de remplissage et les corrections nécessaires desdits deux moyens de remplissage

∘ contrôle la direction et la tension avec lesquelles les remorqueurs (2) tirent radialement sur la fondation à ancrer dans au moins 3 directions différentes espacées selon un angle similaire ; de sorte que la fondation s'enfonce progressivement d'elle-même jusqu'à ce qu'elle repose sur le fond marin dans sa position finale d'installation ;

- des moyens de communication entre les différentes pièces d'équipement recevant les informations des capteurs, des stations GPS (9) situées sur la fondation et d'une station de référence GPS (4) fixe située à un point fixe proche du site d'ancrage de la fondation, tous communiquant des informations à l'unité de contrôle ; et

- une interface utilisateur pour le support à la prise de décision et l'exécution de différentes instructions de contrôle vers ladite unité de contrôle, comportant

∘ des moyens de visualisation des variables et de l'avancement de l'opération,

∘ un logiciel dans lequel les actions de programmation séquentielle sont mises en œuvre et

∘ des moyens qui permettent une intervention manuelle dans l'opération.


 
6. Système selon la revendication 5, caractérisé en que les capteurs incorporés dans les différentes unités du système remplissent les fonctions suivantes :

- mesurer le niveau de ballast dans les groupes de cellules,

- mesurer la pression de l'air intérieur dans les cellules,

- mesurer les rotations qui ont lieu,

- déterminer la position absolue de la structure,

- déterminer la position relative de la structure par rapport à la surface sur laquelle elle est installée,

- mesurer le tangage vertical et la réponse inertielle,

- enregistrer les accélérations et les taux de vitesse que les éléments structurels subissent,

- détecter le contact de la structure avec le fond marin, ainsi que les impacts possibles sur d'autres structures,

- mesurer les conditions locales de forçage du milieu marin.


 
7. Système, selon les revendications 5 et 6, caractérisé en ce que l'unité de contrôle dirige et régule les variables suivantes à travers les éléments qui l'intègrent :

- entrée et sortie du ballast liquide dans les groupes de cellules,

- pression intérieure dans les cellules,

- position horizontale de la structure (sur un plan au sol),

- contrôle dynamique de l'assiette et de la gîte (rotations),

- contrôle dynamique de l'installation de la structure sur le fond marin,

- position relative par rapport à la surface d'installation (distance par rapport au fond marin),

- tangage vertical et sa réponse inertielle,

- réponse inertielle des éléments structurels qu'elle peut transporter ou porter,

- impacts possibles sur d'autres structures, les milieux marins ou les fonds marins,

- contact de la structure avec le fond marin.


 
8. Système, selon les revendications 5 à 7, caractérisé en ce qu'il incorpore les moyens de communication suivants :

- une unité de réception des informations provenant des capteurs situés sur la plateforme émergée de la fondation,

- une unité d'intercommunication sans fil (Wi-Fi) entre les navires prévus comme centres de contrôle et le récepteur et l'unité de contrôle des informations provenant des capteurs situés sur la fondation,

- un système de communication UHF entre les stations GPS et la base GPS-RTK (point de référence fixe),

- des moyens de communication entre les unités de détection et de contrôle.


 
9. Système, selon les revendications 5 à 8, caractérisé en ce que l'interface utilisateur qui sert de support à la prise de décision est constituée des éléments suivants :

- des moyens pour la visualisation de variables sensorielles et de contrôle (état) et de l'avancement de chacune des variables d'état opérationnel enregistrées par le sous-système de détection et de contrôle lors des étapes d'ancrage,

- un logiciel dans lequel la séquence d'actions opérationnelles (ouverture de vannes et de tensions dans les treuils des navires) et du seuil opérationnel par étapes d'ancrage, ainsi qu'une correction automatique de seuils sont mises en œuvre,

- des moyens qui permettent une intervention manuelle sur l'opération

- des moyens d'alerte de dépassements du seuil opérationnel et de l'état des opérations du système,

- une vérification croisée de l'état pour démarrer une nouvelle étape ou redémarrer après des arrêts opérationnels.


 




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Cited references

REFERENCES CITED IN THE DESCRIPTION



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Patent documents cited in the description