RU2665207C1 - Protection of stationary vessel from approaching ice - Google Patents

Abstract

FIELD: shipbuilding.SUBSTANCE: invention relates to the field of operation of offshore facilities, particularly those intended for the production of hydrocarbons, in ice conditions. Technologies of protecting a stationary vessel from the approaching ice are proposed. In the example, the system contains an underwater base located on the seabed and a supercharger located on the underwater base below the surface of the water. Supercharger is designed to destabilize the water column under the approaching ice.EFFECT: technical result is to increase safety and improve operating conditions for stationary marine vessels, particularly those intended for the production of hydrocarbons, in ice conditions.19 cl, 7 dwg

Description

[0001] This application claims priority to provisional application for US patent No. 62 / 087,504 filed December 4, 2014, "PROTECTION OF STATIONARY SHIP FROM MOVING ICE", the contents of which are incorporated into this description by reference.

Field of Invention

[0002] The present invention relates to the protection of fixed vessels from sea ice. More specifically, the present technology is a direction for breaking sea ice drifting to a stationary vessel.

Background

[0003] This section is intended to represent various aspects of this technical field that may be associated with illustrative embodiments of the present invention. It is believed that the present invention helps to create the basis for a better understanding of specific aspects of the proposed technology. Accordingly, it should be understood that this section should be taken in this light and not necessarily as a description of the prototype.

[0004] Attention to Arctic drilling has recently gone beyond the shallows, i.e. from depths less than 100 m, in deep water, i.e. to a depth of more than 100 m. However, arctic conditions in combination with great depth greatly complicate the work. Such difficulties are caused by problems with maintaining a constant position of the vessel, which is the ability of the vessel to maintain a position over a certain section of the bottom, for example, a borehole.

[0005] Maintaining a constant position is often important to prevent stresses in the pipeline connecting the vessel to the subsea field and in the cables connecting the vessel to the seabed. Maintaining a constant position of the vessel can be carried out passively, for example, by mooring cables, dynamically using a supercharger system, or a combination of these two methods. In arctic conditions, floating sea ice can interfere with maintaining a constant position. While stationary offshore platforms are in direct contact with the seabed and can withstand forces of up to tens of thousands of tons, floating platforms are anchored on the seabed with mooring systems that can withstand forces in the range of 1000-2000 tons.

[0006] Although subsea development may be a viable concept for deep-sea exploration in the Arctic, some operations should still be carried out from the surface, such as drilling subsea wells or loading crude oil from an undersea storage facility and others. The use of known technologies should be made in a season of ice-free water. However, in many places in the Arctic, the season of ice-free water can be limited, very variable, and, in some years, may not occur at all. Accordingly, systems to protect platforms and other vessels from drifting ice may be useful. The extension of the season of ice-free water depends on icebreakers, the number of which may be limited and which are expensive to operate.

SUMMARY OF THE INVENTION

[0007] In an illustrative embodiment, a system for protecting a stationary vessel from pending ice is provided. The system comprises an underwater base located on the seabed and a supercharger located on the underwater base below the surface of the water. The supercharger is configured to destabilize a column of water under the approaching ice.

[0008] In another illustrative embodiment, a method for protecting a location on a water surface from pending ice is provided. The method comprises the steps of detecting impending ice and activating a traction device located on the seabed, while the supercharger destabilizes the column of water under the impending ice.

[0009] In another illustrative embodiment, a method for producing hydrocarbons is provided. The method comprises the steps of positioning a vessel at a location on the surface of the sea. A supercharger mounted on a base on the seabed is placed near this location. Hydrocarbons are extracted from a well using a ship. Discover ice approaching the ship. A supercharger is activated to destabilize a column of water under the ice.

Brief Description of the Drawings

[0010] The advantages of the present invention will be more apparent from the following detailed description with reference to the attached drawings, where:

[0011] FIG. 1 is a schematic diagram of the use of anchored superchargers to protect a stationary vessel from impending floating ice.

[0012] FIG. 2 is a schematic diagram showing superchargers breaking cracking floating ice.

[0013] FIG. 3 is a schematic diagram showing a single supercharger destabilizing a column of water under an approaching ice floe.

[0014] FIG. 4 - the only supercharger that can be used to break the oncoming floating ice.

[0015] FIG. 5 is a schematic diagram of a drilling point showing the location of sensors and blowers that can be used to protect a ship.

[0016] FIG. 6 is a flow chart of a hydrocarbon production method using blowers to break floating ice before it reaches a drilling point.

[0017] FIG. 7 is a flow diagram of a method for using blowers to break floating ice before it reaches a point on the surface.

Detailed description

[0018] The following is a detailed description of specific embodiments of the proposed technology. However, to the extent that the following description relates to specific embodiments or specific uses of the present invention, it has only illustrative purposes and is merely intended to describe the options. Accordingly, the present invention is not limited to the specific options described below, but includes all alternatives, modifications, and equivalents included in the true inventive idea and scope defined by the appended claims.

[0019] As described above, protecting a ship or vessels in a position on the sea surface from pending ice can be a problem, especially in deepwater operations. Accordingly, embodiments of the present invention provide protection against ice approaching a surface location. Superchargers are mounted in positions along the seabed and are used to destabilize the water column under floating ice. Destabilization of the water column can lead to the breaking of floating ice into fragments that do not create so much pressure on the vessel. In some embodiments, a supercharger can be used to control pieces of ice, such as hummocks and icebergs, leading them away from the vessel.

[0020] Blowers can be installed in arcs in front of the vessel, for example, in the general direction of the oncoming floating ice to break or deflect the floating ice before it reaches the vessel. In some embodiments, the submarine base comprises guides (or paths) mounted on the seabed. Superchargers can be mounted on the rail, which allows you to change the position of the engines more efficiently. For example, the rail can be fixed on berth piles, for example, on vacuum piles used to moor a ship in place. Combinations of these technologies can be used to create multiple lines of defense. For example, fixed superchargers can be installed in an arc in front of the vessel, and the rail can be laid next to fixed superchargers, which allows additional superchargers to be moved in place as needed. Likewise, several rows of rails with superchargers installed to protect ships can be laid around the protected location, which allows, as necessary, to move many superchargers on each of the rails to the desired location.

[0021] The superchargers can be controlled and receive power from the protected vessel or can have a separate power, control, or both of these systems. In some embodiments, the superchargers may have sensors for detecting objects, such as marine animals, ships, floating ice, etc. Object detection can be used to adjust the depth of the supercharger in the water column, to turn off the supercharger, or both to prevent collisions and damage.

[0022] FIG. 1 is a schematic diagram of the use of anchored superchargers 102 to protect a vessel 104 from pending floating ice 106. A vessel 104 may be a drilling vessel used to drill a well 108 to a field located beneath the seabed 110. However, according to the present invention, using the proposed technology, protect any number of vessels, including tankers, floating storage, loading and mining vessels, etc. If the vessel 104 is located in deep water, for example, at a depth of more than 100 m, it cannot be in direct contact with the seabed 110. In this example, it is important to maintain a position to protect equipment and pipes passing between the vessel 104 and the seabed 110, for example, a riser columns 112.

[0023] The position can be maintained by mooring ropes 114, for example, connected to piles 116 clogged to the bottom 110. Piles 116 can be sunk into the seabed by vacuum driving. Vacuum piles are drawn into the soft surface of the seabed when the open end of the piles is brought into contact with the seabed and then pumped out water from the chamber located on the top of the pile. In some embodiments, the position can be maintained by the helical columns 118 on the vessel 104. You can also use combinations of these technologies, for example, using the mooring cable 114 to hold the vessel 104 in place, and the helical columns 118 to maintain the tension of the mooring cable 118 and keeping the vessel 104 from transverse displacements.

[0024] Pending floating ice 106 or ice torsos 107 may approach the vessel 104 and interfere with maintaining position, for example, forcing the vessel to disconnect the riser drill string 112 from the well 108, lift it, and leave the ice path. The use of superchargers 1-2 in the water column 120 can ease the severity of the problem caused by the floating ice 106. The superchargers 102 can be positioned on an underwater base by attaching the superchargers 102 to the base with halyards 122. The underwater base can comprise a frame and one or more piles. The frame, which is called the "foundation", can be attached to piles 126, hammered into the bottom 110. Piles 126 can be driven into the seabed 110 or they can be vacuum piles. In other embodiments, the supercharger can be attached to the base 116, used to moor the stationary vessel 104. For example, mooring cables for the drilling vessel 104 can be attached to a series of vacuum piles located around the vessel. Each of the vacuum piles can also be used as a fastening point for anchoring the superchargers 102. This will allow the superchargers to be moved between the looming floating ice 106 and the stationary vessel.

[0025] A power and control cable 128 may extend from the vessel 104 to each halyard 122 for supplying power to a blower 102 attached to the halyard 122. In some embodiments, an underwater generator may be used to supply power to the blower 102. Further, power can be supplied to the blowers 102 from the onshore power plant, depending on how far the field is from the coast, eg, within 50 miles of the coast or less.

[0026] Blowers 102 may be made of several ship propeller installations, such as tunnel blowers, manufactured, among others, by Rolls-Royce PLC, London, England and Thrustmaster, Texas, USA. The size selection of the blowers 102 may depend on the position of the vessel 104 and the likely type of ice encountered, for example, one-year ice, two-year ice, and the like. In some embodiments, blowers 102 may have a power of approx. 180 kW to 1 MW, while in other areas superchargers can have a power of approx. 3 MW to approx. 8 MW.

[0027] Since the superchargers 102 can take water from above and throw it out from below, the halyard 122 remains taut. Further, the halyard 122 can be coiled so that the supercharger 102 can move vertically in the water column 120 so that the halyard 122 does not sag. Supercharger 102 can change its vertical position in the water column by adjusting its buoyancy. This allows the use of superchargers 102 at different depths and to avoid suspended underwater ridges of hummock ice.

[0028] In some embodiments, the supercharger 102 may be configured to reverse the flow, i.e. collect water at the bottom of blower 102 and throw it up. This may allow the supercharger to deflect the hummocks 107 from the vessel 104 when they are too large to break. In this case, the supercharger 102 can not be installed on the foundation 124 using a flexible halyard 122, but can be placed on an underwater base, securing the supercharger with a rod or other rigid part. The rod may be pivotally attached to the bottom, which will allow the supercharger to be lowered in the water column 120, for example, to avoid a collision.

[0029] FIG. 2 is a schematic diagram showing superchargers 102 breaking up looming floating ice 202. Reference numerals denote the same elements as in FIG. 1. In this example, superchargers 102 are configured to draw water through top 204 and expel water through bottom 206, as shown by arrows. suctioning the water from the floating ice 202 can cause it to fall under its own weight, as shown by the cracks 208 formed in the floating ice 202. The fragments 210 resulting from the sinking are too small to cause problems to maintain the position of the vessel.

[0030] The halyards 122 can be used to define the vertical depth 212 at which the superchargers 102 are held below the ocean surface 214. Depth 212 can be selected taking into account a combination of factors, including the expected size of floating ice 202, the clearance required for ships to operate in this area, and the size of the superchargers 102. In various embodiments, the superchargers 102 can be installed at depths of 5 to 30 m below the surface.

[0031] FIG. 3 is a schematic diagram of one supercharger 102 destabilizing a water column 300 under a floating ice shield 302. Reference numerals denote the same elements as in FIG. 1 and 2. As described above, the supercharger 102 may draw inlet water 304 through the top 204 and discharge the outlet water 306 through the bottom 206. This stream can lower the pressure in the water column 300 under the ice shield 306, resulting in loss of ice support 302 of the shield. Cracks 308 can form in the ice shield 302 and, as the ice field moves over the unstable water column 300, these cracks can propagate through the field 302, breaking it into smaller fragments.

[0032] Water discharged from the bottom 206 of the blower 102 may flow through a grate or other structure deflecting the flow to the side. This is useful to prevent erosion of the ocean floor beneath supercharger 102, which can lead to loss of reliability of piling 126.

[0033] Although superchargers 102 can break ice shields 302 and floating ice 202, they can also be useful in controlling larger ice structures, such as ice hummocks. For example, the flow from the superchargers 102 can be used to change the way the ice hummock moves, diverting it from the ships. This can be done by swirling and indenting, which create on the surface above the blower 102, for example, a whirlpool. A control system can be used to determine how to use superchargers 102 to deflect larger ice structures.

[0034] FIG. 4 is a drawing of one supercharger 102 that can be used to break oncoming floating ice. Reference numerals denote the same elements as in FIG. 1-3. As described above, the supercharger 102 is connected to the halyard 122, through which power can also be supplied and controlled. The inlet water 304 is sucked into the open top 204 by a supercharger screw 402, which is driven by a motor 404. The motor 404 may be an electric motor or a hydraulic motor, for example, driven by the flow of sea water from a pump on a ship. Outlet water 306 is discharged through the bottom 206 of the blower 102. As described above, a grate can be used to deflect the outlet water 306 to prevent a direct impact to the bottom of the sea, which reduces erosion around the mounting piles or rails.

[0035] The supercharger 102 may have buoyancy compartments 408 that can be used to increase or decrease the depth of the supercharger 102. The buoyancy compartments 408 can be, for example, hollow vessels that can be partially or completely filled with air from the compressor on board the vessel. The buoyancy compartments 408 may not be effective in adjusting the depth when the supercharger 102 is in operation, since the generated thrust may tend to push the supercharger 102 closer to the surface of the water. However, the buoyancy compartments 408 may be useful for lowering the supercharger 102 to avoid impact with the object when the supercharger 102 is turned on. Such objects can be detected or identified by various means, such as a sensor 410 mounted on the supercharger 102. When an approaching object, such as a ship or marine mammal, is detected, among others, the supercharger 102 can be turned off, lowered to a great depth, or both can be done together .

[0036] The blower 102 can be mounted on the halyard 122 using a frame 412 extending from the halyard 122 to the outer casing 414. In addition to the open top 204 and the bottom 206, the outer casing 414 may have other openings 416 that can be used to desire differential traction if it's necessary. One or more of the side openings 416 may be configured to move the supercharger 102 sideways, for example, to tilt sideways. The amount of thrust generated by these openings 416 can be controlled using dampers 418, which can be opened or closed by a control signal sent by operator 420 from the ship.

[0037] FIG. 5 is a schematic diagram of a drilling point 500 showing the location of sensors 502 and superchargers 102 that can be used to protect a vessel 104. Reference numbers indicate the same elements as in FIG. 1. In this example, the ship 104 is protected by two sets of superchargers 102. The first set is mounted on a rail 504, which allows the superchargers 102 to be moved as needed. A second set of superchargers 102 is located inside the rail 504, for example, in the direction of drifting ice relative to the vessel 10. The rail 504 also reduces the total number of superchargers 102 needed, allowing the superchargers to be moved back and forth across the front of the advancing ice.

[0038] In that example, the ice sheet 510 moves in the drift direction 512 toward the vessel 104. Further, ice hummocks 514 can be soldered into the ice sheet 510. Three zones can be defined around the vessel 104 to respond to the oncoming ice. In the outer zone defined by the first circle 516, oncoming ice is detected, such as an ice sheet 510 and hummocks 514, and tracked to determine the measures to be taken. The outer zone may have a radius of approx. 10 to 40 km or more.

[0039] The middle zone may be defined by a circle 518, for example, with a radius of 2 to 10 km. Sensors 502, such as sonars, can be installed along the second line 518 to determine the approach of ice. Pending ice can also be detected by other means, for example, by satellite images, optical means or direct observation. The middle zone can be used as an ice control zone. For example, the superchargers 102 mounted on the rail 504 can be moved around the circumference to the position for breaking the ice sheet 510 into fragments 520, as this shield crosses the line of the superchargers 102. The second set of superchargers 102 installed inside the rail 504 can be used for further splitting the ice sheet 510 or to deflect at least part of the ice hummocks 514. A second set of superchargers 102 can also be mounted on the rail so that their operation is more efficient. An icebreaker 522 can be used to deflect hummocks 514 that are too large to be deflected by the superchargers 102. The use of superchargers 102 to break most of the ice sheet 510 can allow the icebreaker 522 to operate more efficiently, use fewer icebreakers or even a single icebreaker 522 to protect the ship 104 from the oncoming ice.

[0040] The inner zone can be defined by the third circle 524. The third circle 524 can be located 1-2 km from the vessel 104 and can be determined at a distance that gives the vessel 104 enough time to secure and disconnect the drill riser from the well or other submarine connections to move away from oncoming ice.

[0041] FIG. 6 is a flow chart of a hydrocarbon production method 600 using blowers to break ice before it reaches a working location, such as a drilling point. Method 600 begins at block 602, wherein the vessel is positioned at a position on the sea surface. At 604, a supercharger attached to the base is installed at the bottom of the sea. At step 606, during hydrocarbon production by the ship, oncoming ice is detected. At 608, a supercharger is activated to destabilize the column of water under ice.

[0042] FIG. 7 is a flow chart of a method 700 for using superchargers to break ice before ice reaches a surface position. Method 700 begins at block 702, where ice is detected approaching a surface position. At 704, a supercharger mounted on the seabed is activated to destabilize the water column under the ice.

[0043] Although various changes can be made to the proposed technologies and alternative forms given to them, the options described above were given only by way of example. However, it should be understood that these technologies are not limited to specific options. The proposed technologies include all alternatives, modifications and equivalents covered by the inventive idea and the scope of the attached claims.

Claims (33)

1. A system for protecting a fixed vessel from impending floating ice, comprising: an underwater base located on the seabed; a supercharger having a top and bottom located on an underwater base below the surface of the water, the supercharger being configured to provide a water flow to the top of the supercharger to destabilize the water column under the advancing floating ice so that cracks form in the floating ice when floating ice moves over the destabilized water column and discharging a substantial amount of water from the buoyant ice to allow the buoyancy of buoyant ice under its own weight, and a sensor located on the supercharger and configured to detect an approaching object and, in response to detecting an approaching object, issuing a command to turn off the supercharger, increase its depth, or both together, in order to avoid a collision with a detected approaching object. 2. The system of claim 1, comprising a cable extending from a fixed vessel to an underwater base, while power, control signals, or both, are transmitted to the supercharger via a cable. 3. The system of claim 1, comprising a sonar configured to detect oncoming floating ice. 4. The system of claim 1, wherein the underwater base comprises a foundation and one or more piles. 5. The system of claim 4, wherein the one or more piles comprises a vacuum pile buried in the seabed. 6. The system according to claim 1, in which the underwater base contains a rail for changing the position of the supercharger. 7. The system of claim 1, wherein the supercharger draws water through the top of the supercharger and throws water down to the seabed. 8. The system of claim 1, wherein the supercharger is further configured to reverse the flow, so that water is drawn through the bottom of the supercharger and is thrown up to the surface of the water to deflect floating ice from the vessel. 9. The system of claim 1, wherein the supercharger comprises one or more side openings for moving the supercharger sideways. 10. The system of claim 1, wherein the supercharger comprises a lower grill for redirecting water outward from the supercharger. 11. The system of claim 1, wherein the supercharger comprises one or more buoyancy compartments for adjusting the vertical depth of the supercharger. 12. The system of claim 1, wherein the plurality of submarine bases are configured to form a plurality of arcuate rails. 13. The system according to claim 1, in which the supercharger is located on the underwater base using a halyard rolled up in a spiral to allow vertical mobility relative to the base. 14. The system of claim 1, comprising an underwater generator for supplying power to the supercharger. 15. A method of protecting a location on the sea surface from impending floating ice, in which: detect oncoming floating ice, and they activate a supercharger installed on the seabed, while providing a flow of water to the top of the supercharger to destabilize the water column under the floating ice so that cracks in the floating ice form when the floating ice moves over the destabilized water column, and a significant amount of water is drained from the floating ice to ensuring the failure of floating ice under its own weight, detect an approaching object with a sensor located on a supercharger installed on the seabed, and In response to the detection of an approaching object, a command is issued to turn off the supercharger, increase its depth, or both, in order to avoid a collision with a detected approaching object. 16. The method according to p. 15, in which the superchargers are moved to positions designed to cross the oncoming floating ice. 17. The method according to p. 15, in which power is supplied to the blowers from the vessel at a location on the sea surface. 18. The method according to p. 15, in which the destabilization of the water column further includes the step of drawing water through the bottom of the supercharger and throwing water up to the surface of the water to deflect floating ice from the vessel. 19. A method of producing hydrocarbons, in which: position the vessel at a location on the surface of the sea, position the supercharger attached to the base on the seabed, produce hydrocarbons from a well using a vessel, detect floating ice approaching the ship, and activating the supercharger to ensure the flow of water to the top of the supercharger to destabilize the water column under the floating ice so that cracks in the floating ice are formed when the floating ice moves over the destabilized water column, and a significant amount of water is discharged from the floating ice to allow the floating ice to fall through under the action of own weight detect an approaching object with a sensor located on the supercharger, and in response to the detection of an approaching object, they issue a command to turn off the supercharger, increase its depth, or both, in order to avoid a collision with a detected approaching object.

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