Pipe retrieval

Abstract

A method and apparatus for retrieving a subsea flexible pipe and a method for retrieving a subsea pipeline arrangement are disclosed. An apparatus for providing data during a flexible pipe retraction process of an underwater flexible pipe, comprising: an annulus connection member comprising a housing connectable to a bleed outlet of an end fitting of the flexible pipe; and a fluid communication passage having a first end connected to and in fluid communication with the annulus connection member and another end connected to and in fluid communication with an annulus pressure sensor located in the waterproof housing.

Description

[0001] The present invention relates to a method and apparatus for retrieving flexible pipe. In particular, but not exclusively, the invention relates to regulating the pipe retrieval rate based on the annulus pressure in the flexible pipe body of the flexible pipe as it is lifted during retrieval.

[0002] Flexible pipe is widely used in offshore applications of the oil and gas industry for transporting oil, natural gas, water or other fluids from one location to another. Flexible pipe is particularly useful when connecting a sea level support structure and a seabed location (which can be deep underwater, such as 1000 meters or deeper), where the pipe can serve as a riser. Flexible pipe is generally formed as an assembly of a flexible pipe body and one or more end fittings. The flexible pipe body can have an inner diameter generally up to about 0.6 meters (for example, a diameter can be in the range of 0.05m to up to 0.6m). Due to their location, flexible pipe is exposed to a series of challenging conditions, which may have high pressure, seawater, high tensile strain and corrosive environments. Therefore, the flexible pipe body is composed of several concentric polymer layers, metal layers and / or composite layers. For example, the pipe body may include a polymer layer and a metal layer, or a polymer layer and a composite layer, or a polymer layer, a metal layer and a composite layer. The layer can be formed by a single piece (such as an extruded tube), or by spirally winding one or more wires with a desired pitch, or by connecting together a plurality of discrete rings arranged concentrically side by side. Depending on the layers and type of flexible pipe used, some of the pipe layers may be bonded together or left unbonded. The polymer layers typically provide a seal against fluid ingress and the metal layers provide structural rigidity.

[0003] Some flexible pipes have been used in deepwater (less than 3,300 feet (1,005.84 meters) and ultra-deepwater (greater than 3,300 feet) developments. The growing demand for oil requires exploration at greater and greater depths, where environmental factors are more extreme (e.g., greater than 8202 feet (2500 meters)). For example, in such deepwater and ultra-deepwater environments, ocean floor temperatures increase the risk of produced fluids cooling to a temperature that can cause pipe plugging. In practice, flexible pipes are conventionally designed to operate at operating temperatures of -30°C to +130°C, and pipe bodies for even more extreme temperatures are being developed. Increased depths also increase the pressures that must be applied to flexible pipes. The pressure associated with the environment in which it must operate. For example, a flexible pipe may be required to operate with an external pressure acting on the pipe in the range of 0.1 MPa to 30 MPa. Similarly, the transportation of oil, gas or water may well result in high pressures acting on the flexible pipe from the inside, for example internal pressures acting on the pipe from bore fluids in the range of zero to 140 MPa. Consequently, the need for high levels of performance and environmental adaptability of certain layers of the flexible pipe body, such as the pipe carcass layers or the pressure or tensile armor layers, is increased. It is noted for the sake of completeness that flexible pipe may also be used in shallow water applications (e.g., depths of less than about 500 meters) or even in coastal (onshore) applications.

[0004] The innermost layer of the flexible pipe body typically includes an inner jacket, which can be an extruded, non-porous polymer layer that confines porous fluids to its inner circumference. It also typically includes a carcass, a spirally wound, interlocking metal structure that forms this innermost layer. The carcass prevents collapse of the inner liner and also protects it from abrasive particles. When a carcass layer is present in the flexible pipe body, the inner jacket is referred to as a barrier layer. When a carcass layer is not present in the flexible pipe body, the inner jacket is referred to as a liner.

[0005] The outermost layer of a flexible pipe is an outer sheath, an extruded non-porous polymer layer that protects the structural elements of the pipe from the environment surrounding the flexible pipe and prevents the ingress of seawater.

[0006] For some flexible pipes that include an intermediate polymer layer, the flexible pipe body may include multiple annuli. However, for many flexible pipes, only an outer polymer layer and an inner polymer layer are included. The annulus of such flexible pipes is the region between the innermost fluid-containing layer and the outermost fluid-containing layer. The innermost layer within the annulus region is the pressure armor layer, which is made of helically wound flat metal wire arranged at a layout angle close to 90°. Adjacent windings in the pressure armor layer interlock to control the gap between the coils. The pressure armor is designed to withstand hoop stresses in the pipe wall caused by bore fluid pressure. Pairs of tensile armor layers are also located within the annulus, and these tensile armor layers are radially cross-wound outside the pressure armor layers. The tensile armor layers are typically made of slightly flattened rectangular metal wire arranged at a layout angle of approximately 30-55°. The tensile armor layers support the weight of all internal pipe layers and transfer the resulting tensile stresses to the sea-level support structure. The annulus may also have other layers, such as tape to resist wear and strand separation, as well as thermal insulation. Therefore, the carbon steel wire in the annulus often takes on the characteristics of flexible pipe used in subsea environments.

[0007] In an end fitting, the flexible pipe is typically terminated by sealing and securing the ends of the polymer or composite layers, securing any pressure armor coils, and securing the tensile armor wires. Consequently, the annulus extending along the main body section of the flexible pipe extends into the area within the end fitting. In a configuration where two flexible pipes are joined end-to-end to form a piping arrangement, there is no fluid connection between the annulus in one section of flexible pipe and the annulus in the other section of flexible pipe.

[0008] The annulus of a flexible pipe body is typically free of fluids other than air during transport, except for the occasional use of a small amount of lubricant during manufacturing. That is, when the flexible pipe is laid, for example, on the seafloor during installation, the annulus of the flexible pipe is not intended to contain significant amounts of hydrocarbons or acids, such as gases or liquids. Following installation, over time, the annulus of the flexible pipe gradually fills with fluid. This is due to gases, and possibly liquids, diffusing from the seawater through the outer jacket into the annulus due to factors such as pressure, temperature, outer jacket material, and outer jacket thickness. Sometimes, due to these factors, hydrocarbons or acids, such as gases, may also or alternatively diffuse from the bore fluid through the inner jacket into the annulus and condense and / or dissolve into the existing fluid. This is particularly true when the bore fluid contains a high proportion of certain gases and can be particularly problematic for flexible pipes located geographically close to wellheads in pipeline installations.

[0009] Therefore, the annulus of the flexible pipe that has been placed on the seabed for a period of time may accumulate the annulus gas to high pressure. If the pressure of the annulus gas is allowed to increase unrestricted, the pressure of the annulus gas on the inner side of the outer jacket may exceed the hydrostatic pressure of the seawater on the outer side of the outer jacket to a certain extent, so that the outer jacket bursts (relative to the external hydrostatic pressure, the actual annulus overpressure may be different according to the structure of the outer jacket layer of the pipeline and whether there are any reinforcements on the layer or whether there are any reinforcements in the layer). In order to alleviate this problem, at least two (usually three) pressure relief valves are often installed in each end fitting of the flexible pipe, as specified by the API 17J standard for non-bonded flexible pipes. Therefore, when the annulus fluid pressure exceeds a certain threshold value (usually 2-3 bars) of hydrostatic seawater pressure, the valve opens and "exhausts" to relieve the pressure in the annulus. Therefore, the valve serves as a bleed valve and helps prevent the outer jacket from bursting due to the pressure in the annulus. The maximum flow rate of the valve, the release pressure of the valve, etc. can be selected to limit the entry of seawater into the annulus during exhaust.

[0010] At certain times, it may be necessary to retrieve a flexible pipe that has been installed in a subsea environment. For example, when the flexible pipe is no longer in use; when the flexible pipe is to be redeployed at another location; when modifications are to be made, etc. During the retrieval process, the flexible pipe body is pulled upward from its installation location and spooled onto a reel on a pipelay support vessel (PLSV) or lifted in other ways. As described above, if the flexible pipe has been placed in the subsea environment for some time, the annulus of the flexible pipe may contain pressurized gas and / or liquid. When the flexible pipe is lifted from its underwater installation location toward the horizontal plane, the hydrostatic pressure outside the outer jacket of the flexible pipe will decrease at a rate of approximately 1 bar (0.1 MPa) for every 10 m decrease in water depth, while the annulus gas pressure does not change with water depth. Therefore, as the flexible pipe body is lifted, the hydrostatic pressure outside the outer jacket can decrease relative to the annulus pressure inside the outer jacket. As described above, when the annulus pressure exceeds a certain threshold of hydrostatic pressure, the valve in the end fitting of the flexible pipe will open to release the excess pressure. If the flexible pipe is raised toward the horizontal faster than the valve can relieve the excess pressure, the flexible pipe outer jacket may burst due to the excessive annular pressure.

[0011] Typically, the retraction rate during retraction of the tubing into the PLSV is limited by the ability of the pressure relief valves in the end fittings of the flexible pipe to reduce the annular pressure. Sometimes, if necessary, the tubing retraction rate can be set to a fixed safety value to give the valves time to reduce the annular pressure. At other times, a camera on a remotely operated vehicle (ROV) can be used to monitor bubbles when the valves in the end fittings are open to inform when to reduce the tubing retraction rate. This tubing retraction rate is often chosen conservatively, giving a large margin for error, because the annular pressure can vary significantly when above the venting threshold, and there can be uncertainty about the number of pressure relief valves that open and the amount of gas released, affecting the time required to safely reduce the annular pressure. As a result, tubing retraction can be an unduly slow process, increasing costs and downtime relative to the desired rate.

[0012] It is an object of the present invention to at least partially alleviate one or more of the above problems.

[0013] It is an object of certain embodiments of the present invention to help prevent the outer sheath from rupturing during tubing retrieval.

[0014] It is an object of certain embodiments of the present invention to provide a method for maximizing pipeline retrieval speed in a safe manner.

[0015] It is an object of certain embodiments of the present invention to provide an apparatus for measuring annulus pressure in a flexible pipe.

[0016] It is an object of certain embodiments of the present invention to provide a method for retrofitting a deployed flexible pipe with pressure monitoring capabilities.

[0017] Certain embodiments of the present invention aim to provide a method for maximizing the pipe retrieval rate of a flexible pipe by wirelessly transmitting data, such as annular pressure and hydrostatic pressure, from the end fittings of the flexible pipe to a pipe laying support vessel (PLSV), which can adjust the pipe retrieval rate based on the data.

[0018] According to a first aspect of the present invention, there is provided a method for retrieving an underwater flexible pipe, the method comprising:

[0019] Push the end region of the flexible pipe toward the floating platform at the flexible pipe retraction speed, thereby passing through

[0020] The water lifts the flexible pipe;

[0021] When the flexible pipe is lifted, a relationship between the annular pressure in the annular region of the flexible pipe and the local water pressure near at least one bleed outlet on the end fitting of the flexible pipe is determined.

[0022] Department; and

[0023] The flexible tube retraction speed is selected responsive to the relationship.

[0024] In certain embodiments, the step of selecting a retraction speed comprises:

[0025] repeatedly determining the maximum feasible retraction speed; and

[0026] The flexible pipe retraction speed is set at or within 10 m / h below the maximum possible retraction speed.

[0027] In certain embodiments, the method further comprises:

[0028] The flexible tube retraction speed is selected according to the following formula:

[0029] AP <WP+SM

[0030] Where AP is the annulus pressure close to the bleed outlet, WP is the local water pressure close to the bleed outlet, and SM is a predetermined safety margin.

[0031] In certain embodiments, the predetermined safety margin is at least 2 bar, and optionally at least 3 bar.

[0032] In certain embodiments, the method further comprises:

[0033] repeatedly measuring annular pressure (AP) proximate the bleed outlet and repeatedly determining local water pressure (WP) proximate the bleed outlet as the flexible pipe is lifted; and responsively determining rates of change of annular pressure and water pressure.

[0034] In certain embodiments, the method further comprises:

[0035] securing a module comprising a housing containing an annulus pressure sensor and a local water pressure sensor to the end fitting; and

[0036] A corresponding fluid communication passage in fluid communication with the annulus pressure sensor is secured between the housing and the bleed outlet.

[0037] In certain embodiments, the method further comprises:

[0038] communicating the local water pressure to the local water pressure sensor via a water pressure port in the housing and a corresponding further fluid communication path between the water pressure port and the local water pressure sensor; and

[0039] The annulus pressure is communicated to the annulus pressure sensor via the first fluid communication passage.

[0040] In certain embodiments, the method further comprises:

[0041] The annulus pressure value and the local ambient water pressure value are transmitted wirelessly from the module.

[0042] In certain embodiments, the method further comprises:

[0043] A first fluid communication passage in fluid communication with an annulus pressure sensor located on a remotely operated vehicle (ROV) is secured to the bleed outlet. The ROV also includes a local water pressure sensor.

[0044] In certain embodiments, the method further comprises:

[0045] Wireless communication occurs by sending ultrasound signals from an ultrasound modem in the module, or by sending light from one or more light emitting elements on the housing, or by sending wireless signals wirelessly from an ROV in close proximity to the module.

[0046] According to a second aspect of the present invention, there is provided an apparatus for providing data during a flexible pipe retrieval process of an underwater flexible pipe, the apparatus comprising:

[0047] an annulus connection member comprising a housing connectable to a bleed outlet of an end fitting of a flexible pipe; and

[0048] A fluid communication passage has a first end connected to the annulus connection member and in fluid communication with the annulus connection member, and another end connected to an annulus pressure sensor located in the waterproof housing and in fluid communication with the annulus pressure sensor.

[0049] In certain embodiments, the annulus connection member includes a rigid body having a first body end region including a bleed valve and a bleed hole, and another body end region including a fixing element for fixing to the orifice of the bleed outlet.

[0050] In certain embodiments, the apparatus further comprises:

[0051] A module includes the waterproof housing and the annulus pressure sensor, and further includes a water pressure port including an opening in the housing and the fluid communication passage extending between the opening and the water pressure sensor in the housing.

[0052] In certain embodiments, the apparatus further comprises:

[0053] A wireless modem includes a transmitter element for transmitting annular pressure values ​​and local water pressure values.

[0054] In certain embodiments, the apparatus further comprises:

[0055] A storage medium is used to record a plurality of annular space pressure values, local water pressure values ​​and time values ​​associated with the annular space pressure values ​​and the local water pressure values.

[0056] In certain embodiments, the apparatus further comprises:

[0057] A remotely operated vehicle (ROV) includes the waterproof housing and the annulus pressure sensor, and also includes a water pressure port, the water pressure port including a through opening located in an outer wall of the ROV and a fluid communication channel extending between the opening and the water pressure sensor in the housing of the ROV.

[0058] In certain embodiments, the apparatus further comprises:

[0059] A wireless modem includes a transmitter element for transmitting annular pressure values ​​and local water pressure values.

[0060] In certain embodiments, the fixation element comprises a piercing element for fixation to the aperture of the deflation vent.

[0061] According to a third aspect of the present invention, there is provided a method for retrieving an underwater pipeline device, the method comprising:

[0062] advancing the flexible tube end of each of a plurality of flexible tubes of a piping arrangement individually toward the surface platform, thereby lifting the piping arrangement through the water, the piping arrangement comprising the plurality of flexible tubes arranged in an end-to-end configuration; and

[0063] As the flexible pipe of the piping arrangement is lifted, a flexible pipe retraction speed is varied in response to the environmental control pressure in the environmental control zone of the current uppermost flexible pipe of the piping arrangement to maintain at least a predetermined average flexible pipe retraction speed of the piping arrangement.

[0064] In certain embodiments, the method further comprises:

[0065] The flexible tube retraction speed is also varied in response to local water pressure adjacent a currently uppermost flexible tube of the plumbing arrangement.

[0066] In certain embodiments, the method further comprises selecting the flexible tube retraction speed according to the following formula:

[0067] AP <WP±SM

[0068] Where AP is the annulus pressure close to the bleed outlet, WP is the local water pressure close to the bleed outlet, and SM is a predetermined safety margin.

[0069] In certain embodiments, the flexible tube retraction speed is a constant flexible tube retraction speed.

[0070] In certain embodiments, the flexible tube retraction speed is a variable flexible tube retraction speed.

[0071] Certain embodiments of the present invention provide a method of monitoring the annulus pressure of a flexible pipe that has been deployed to a subsea environment.

[0072] Certain embodiments of the present invention provide a method of monitoring hydrostatic pressure at a flexible pipe deployed to a subsea environment.

[0073] Certain embodiments of the present invention provide an apparatus that monitors the annular pressure and hydrostatic pressure of a flexible pipe and transmits the data via wire to a pipelay support vessel (PLSV).

[0074] Certain embodiments of the present invention provide an apparatus that monitors the annulus pressure of a flexible pipe and wirelessly transmits the data to a pipelay support vessel (PLSV).

[0075] Certain embodiments of the present invention provide an apparatus that monitors the annulus pressure of a flexible pipe and displays the data.

[0076] Certain embodiments of the present invention provide an apparatus that can be integrated into a control system to regulate the tube retraction speed of a flexible tube.

[0077] Certain embodiments of the present invention provide a method for optimizing a flexible tube retraction rate by reading pressure-related data.

[0078] Certain embodiments of the present invention provide a method that utilizes annular pressure and local water pressure to regulate the flexible tubing retraction rate within safety limits so that the flexible tubing does not burst.

[0079] Embodiments of the present invention will now be described hereinafter, by way of example only, with reference to the accompanying drawings, in which:

[0080] Figure 1 A flexible pipe body is shown;

[0081] Figure 2 The use of flexible tubing as a conduit arrangement and tube retraction are shown;

[0082] Figure 3 The flexible pipe and end fittings with the module attached are shown;

[0083] Figure 4 Another view of the end fitting is shown showing the attached bleed outlet, T-connector, and tubing;

[0084] Figure 5 A pipeline arrangement is shown with wireless communication between the attachment module and the Pipelay Support Vessel (PLSV);

[0085] Figure 6 A method of flexible tube retraction is shown;

[0086] Figure 7 Shows an alternative T-connector and tubing attached to the bleed outlet;

[0087] Figure 8 An alternative arrangement of pipes is shown where there is communication between the module and the ROV, which itself has wired communication with the PLSV;

[0088] Figure 9 An alternative scheme for piping arrangements that allow for communication between the modules, ROV and PLSV is shown;

[0089] Figure 10 An alternative end fitting with a bleed outlet is shown; and

[0090] Figure 11 Another alternative to the end fitting is shown with a bleed outlet.

[0091] In the drawings, like reference numerals refer to like parts.

[0092] Throughout this specification, reference will be made to flexible pipe. It should be understood that certain embodiments of the present invention are applicable to various types of flexible pipe. For example, certain embodiments of the present invention may be used with flexible pipe bodies and associated end fittings of the type manufactured in accordance with API 17J. This type of flexible pipe is often referred to as unbonded flexible pipe. Other embodiments are associated with other types of flexible pipe.

[0093] It will be appreciated that the flexible pipe shown is an assembly of a portion of a flexible pipe body and one or more end fittings (not shown) in each of which a respective end of the pipe body is terminated. Figure 1 It shows how the pipe body 100 is formed from a combination of layered materials that form a pressure-containing conduit. Figure 1 While several specific layers are shown in the figures, it should be understood that certain embodiments of the present invention are broadly applicable to coaxial tube body structures comprising two or more layers made from a variety of possible materials. The tube body can include one or more layers comprising a composite material, thereby forming a tubular composite layer. It should also be noted that the layer thicknesses are shown for illustrative purposes only. As used herein, the term "composite material" is used broadly to refer to a material formed from two or more different materials, such as a material formed from a matrix material and reinforcing fibers.

[0094] Thus, a tubular composite layer is a layer having a generally tubular shape formed from a composite material. Alternatively, a tubular composite layer is a layer having a generally tubular shape formed from a plurality of components, one or more of which are formed from a composite material. The layer or any element of the composite layer may be manufactured via an extrusion, pultrusion, or deposition process, or via a winding process in which adjacent coils of a tape, which itself has a composite structure, are bonded together. Regardless of the manufacturing technique used, the composite material may optionally include a matrix or body of material having a first property, into which additional elements having different physical properties are embedded. That is, elongated fibers that are aligned to a certain extent or smaller fibers that are randomly oriented may be incorporated into the body, or spheres or other regularly or irregularly shaped particles may be embedded into the matrix material, or a combination of more than one of the above. Suitably, the matrix material is a thermoplastic material, suitably, the thermoplastic material is polyethylene or polypropylene or nylon or PVC or PVDF or PFA or PEEK or PTFE or an alloy of such materials with reinforcing fibers made of one or more of glass, ceramic, basalt, carbon, carbon nanotubes, polyester, nylon, aramid, steel, nickel alloy, titanium alloy, aluminum alloy, etc. or fillers made of glass, ceramic, carbon, metal, buckyballs, metal silicates, carbides, carbonates, oxides, etc.

[0095] Figure 1 The pipe body 100 shown includes an internal pressure sheath 110, which serves as a fluid retaining layer and comprises a polymer layer that ensures the integrity of the internal fluid. This layer provides a boundary for any fluid being transported. It should be understood that this layer itself may comprise multiple sublayers. It should be understood that when a carcass layer 120 is utilized, the internal pressure sheath is generally referred to by those skilled in the art as a barrier layer. In operations without such a carcass (so-called smooth bore operations), the internal pressure sheath may be referred to as a liner. Figure 1 The barrier layer 110 is shown in FIG.

[0096] It should be noted that the carcass layer 120 is a pressure-resistant layer that provides an interlocking structure that can be used as the innermost layer to completely or partially prevent the internal pressure sheath 110 from collapsing due to pipe decompression, external pressure, and tensile armor pressure and mechanical breaking loads. The carcass is a pressure-resistant layer. It should be understood that certain embodiments of the present invention are therefore suitable for "coarse hole" applications (having a carcass). Suitably, the carcass layer is a metal layer. Suitably, the carcass layer is formed of stainless steel, corrosion-resistant nickel alloy, etc. Suitably, the carcass layer is formed of a composite material, polymer, or other material or combination of materials and components. The carcass layer is generally positioned radially within the barrier layer.

[0097] The carcass ply is a "ply" in the sense that the radially innermost and outermost surfaces are produced in a single pass at a single manufacturing node. A single manufacturing node may comprise a plurality of strip processing segments axially close together such that these segments are effectively a single node. The node suitably extends over an axial distance of less than 2.5 m. Suitably, the node has a length of 1 m or less.

[0098] The pipe body includes a pressure armour layer 130 which is a pressure resistant layer that provides a structural layer that increases the resistance of the flexible pipe to internal and external pressures and mechanical breaking loads. This layer also structurally supports the internal pressure sheath. Suitably, as Figure 1 As shown, the pressure armor layer is formed as a tubular layer. Suitably, for an unbonded flexible pipe, the pressure armor layer comprises an interlocking construction of wires having a lay angle approaching 90°. Suitably, in this case, the pressure armor layer is a metallic layer. Suitably, the pressure armor layer is made of carbon steel, an aluminum alloy, stainless steel, or the like. Suitably, the pressure armor layer is formed of a pultruded composite interlocking layer. Suitably, the pressure armor layer is formed of a composite material formed by extrusion, pultrusion, or deposition. The pressure armor layer is positioned radially outwardly of the underlying barrier layer.

[0099] The flexible pipe body also includes a first tensile armor layer 140 and a second tensile armor layer 150. Each tensile armor layer is used to sustain tensile loads and, optionally, internal pressure. Suitably, for some flexible pipes, the tensile armor coils are metal (e.g., steel, stainless steel, or titanium, etc.). For some composite flexible pipes, the tensile armor coils may be polymer composite tape coils (e.g., provided with a thermoplastic such as nylon, matrix composite, or a thermoset such as epoxy, matrix composite). For unbonded flexible pipes, the tensile armor layers are formed from a plurality of wires (to impart strength to the layer) positioned above the inner layer and helically wound along the length of the pipe at a lay angle typically between about 10° and 55°. Suitably, the tensile armor layers are counter-wound in pairs. Suitably, the tensile armor layers are metallic layers. Suitably, the tensile armor layers are formed from carbon steel, stainless steel, titanium alloy, aluminum alloy, etc. Suitably, the tensile armor layers have a microstructure composed of oriented lamellae. Suitably, the tensile armour layer is formed from a composite, polymeric or other material or combination of materials.

[0100] Suitably, the flexible pipe body includes an optional tape layer 160 that helps contain underlying layers and, to some extent, prevents abrasion between adjacent layers. The tape layer may optionally be a polymer or composite material or a combination of materials, and may also optionally include a tubular composite layer. The tape layer may be used to help prevent metal-to-metal contact, thereby helping to prevent abrasion. The tape layer on the tensile armor may also help prevent "strand separation" of the tensile armor wires.

[0101] The flexible pipe body also includes an optional insulation layer 165 and an outer jacket 170, which includes a polymer layer used to protect the pipe from penetration, corrosion, abrasion, and mechanical damage by seawater and other external environments. Any insulation layer helps limit heat loss through the pipe wall to the surrounding environment. The annulus region 180 is defined as the space between the inner pressure jacket 110 and the outer jacket 170. In other words, in Figure 1 In the flexible pipe body shown, the pressure armor layer 130, the first tensile armor layer 140, the additional tensile armor layer 150, the optional tape layer 160, and the optional insulation layer 165 are located in an annulus region 180. It should be understood that in some embodiments, the annulus region 180 may include Figure 1 The flexible pipe body shown may contain any or no layers.

[0102] Each flexible pipe comprises at least one portion (referred to as a segment or section) of a pipe body 100 and an end fitting positioned at at least one end of the flexible pipe. A corresponding end fitting may be used to terminate each end of the flexible pipe body. The end fitting provides a mechanical device that forms a transition between the flexible pipe body and the connector. For example, Figure 1 The different pipe layers shown are terminated in end fittings to transfer loads between the flexible pipe and the connector.

[0103] Figure 2 A piping arrangement 200 suitable for transporting produced fluids such as oil and / or natural gas and / or water from a subsea location 221 to a pipelay support vessel (PLSV) 222 is shown. Figure 2 In the PLSV, it can be a ship. For example, in Figure 2 In the embodiment of the present invention, seabed location 221 includes a seabed flow line 225. Flexible flow line 225 includes flexible pipes that are fully or partially resting on or buried below the seabed 230 and are used for static applications. In some alternatives, the PLSV can be provided by a platform. In other alternatives, the PLSV can be provided by a floating platform. Piping arrangement 200 is an assembly. That is, multiple flexible pipes 240 extend between PLSV 222 and the seabed. Piping arrangement 200 has six flexible pipes 2401, 2402, 2403, 2404, 2405, and 2406. In piping arrangement 200, adjacent flexible pipes 240 are joined by fixing their end fittings together in an end-to-end configuration. It should be understood that in other examples, piping arrangement 200 can alternatively have any number of flexible pipes 240.

[0104] In earlier deployments, some pipes may have been used as risers, while some may have been used as flowlines. For example, it should be understood that there are different types of risers, as is well known to those skilled in the art. Certain embodiments of the present invention may be applicable to retrieving any type of riser, such as a freely suspended riser (free-hanging catenary riser), a riser constrained to some degree (buoy, chain), a fully constrained riser, or one enclosed in a tubular (I- or J-tube). Some, but not all, examples of such configurations are found in API 17J. Retrievable portions of flexible pipe have also previously been used as jumpers.

[0105] It should be understood that some segments 240 of the pipe assembly may include thermoplastic composite pipes, i.e., pipes having a structure at least partially made of composite material. Optionally, a pipe assembly including thermoplastic composite pipes may be referred to as a thermoplastic composite pipe device. Optionally, the thermoplastic composite pipe may include multiple adhesive tape layers to provide a pipe with the desired wall thickness and strength (axially and relative to internal pressure). Optionally, the thermoplastic composite pipe may also include additional thermoplastic tubular (usually extruded) layers radially located inside and / or outside the composite material. Optionally, the thermoplastic tubular layer is bonded to the composite material layer of the thermoplastic composite pipe. Optionally, the thermoplastic composite pipe device may not have an annulus in which the permeating gas may accumulate and penetrate through the annulus to the end fittings. Alternatively, some thermoplastic composite piping arrangements may be at least partially annular, and therefore may not be able to connect the annulus of the flexible pipe through-holes on either side of the thermoplastic composite pipe segment to relieve the higher annulus pressure in one or the other flexible pipe segment to the lower annulus pressure in the other flexible pipe segment via a fluid connection.

[0106] Figure 3 The flexible pipe body 100 ( Figure 3 3 and 4. The flexible pipe body 100 includes an inner pressure sheath 110, a carcass layer 120, a pressure armor layer 130, a first tensile armor layer 140, a second tensile armor layer 150, an optional tape layer 160, an optional insulation layer 165, and an outer jacket 170. The annulus region 180 is defined as the space between the inner pressure sheath 110 and the outer jacket 170. In other words, as Figure 3 As shown, annulus region 180 includes pressure armor layer 130, first tensile armor layer 140, second tensile armor layer 150, optional tape layer 160, and optional insulation layer 165. It should be understood that in some embodiments, flexible pipe body 100 may include any combination of the previously described layers.

[0107] The end fitting 320 is a hollow steel component that is generally cylindrical. In other words, the end fitting 320 is substantially rotationally symmetrical. The end fitting 320 is assembled from component parts. Alternatively, the end fitting 320 can be made from a milled or turned metal blank. It should be understood that in some alternative embodiments, the end fitting 320 can be composed of another metal, a metal composite, an alloy, etc. The end fitting 320 has an opening 322. The opening 322 has an inner diameter corresponding to the outer diameter of the flexible pipe body. The opening 322 also has a depth of at least 0.5 m. In some end fittings 320, the opening 322 has a depth of at least 1 m. The end fitting also includes a neck 324. The neck 324 is a hollow tubular shape that terminates in a flange 326. The flange 326 is plate-shaped and has an axial length (thickness) of less than 0.1 m. Some flanges 326 have an axial length of less than 0.2 m. The outer diameter of the flange 326 is greater than the outer diameter of the neck 324. The flanges 326 have two through-holes through their thickness to help facilitate pre-tensioning fasteners used to connect two adjacent flanges 326, whereby the distance from the central axis of the flanges 326 to the through-holes is greater than the radius of the neck 324. It should be understood that in some end fittings 320, the number of through-holes in the flanges 320 may be one, three, four, or more than four. A gasket sealing ring (not shown), such as an API 6A Type BX ring, is clamped between the flanges 326 and seated in a recessed sealing ring groove present in each flange. Other sealing systems and flange connection designs are known to those skilled in the art. It should be understood that in some examples, a gasket may not be used.

[0108] The end fitting 320 of the lower flexible tube 2402 ( Figure 3 The lower end fitting shown in FIG) abuts the adjacent flexible pipe in an end-to-end configuration. Figure 3 320 . The upper end fitting 330 has an opening 322, a neck 324, and a flange 326 as previously described. The first end fitting 320 is secured to the upper end fitting 330 using fasteners in the through-holes of the flange 326. It should be understood that in other embodiments, another fastening method may be used to secure the end fitting 320 and the upper end fitting 330 together. The lower flexible tube 2402, via its end fitting 320, is attached to the other flexible tube 2401 (not shown) via the upper end fitting 330, such that bore fluid can flow freely from the flexible tube 240 to the other flexible tube (not shown) through the end fittings 320, 330.

[0109] In the end fitting 320, the internal pressure sheath 110 and the outer sheath of the flexible pipe body 100 are sealed via sealing rings, while the other layers are terminated to provide mechanical load transfer. The internal pressure sheath is sealed at its end within the end fitting using at least one sealing ring to prevent leakage of bore fluid into the annulus. Similarly, the outer sheath is sealed at its end within the end fitting using another sealing ring to prevent leakage of seawater, etc., into the annulus. The layers within the annulus region 180 terminate within the end fitting within the chamber. A pressure relief valve 335 is located on the end fitting 320. The pressure relief valve is a bleed valve. The pressure relief valve 335 has a bleed outlet (not shown). This bleed outlet is an opening in the pressure relief valve 335. In some examples, the bleed outlet may be an opening in the end fitting 320. The bleed outlet provides an outlet for gas to exit the end fitting 320. It should be understood that in some cases, the pressure relief valve 335 may also be a bleed outlet. For example, the pressure relief valve 335 may be a through-hole. The adapter is fixed to one end of the pressure relief valve 335 in the outer surface of the end fitting 320. At the other end of the adapter is the upper pressure relief valve 345. The top of the upper pressure relief valve 345 includes a bleed outlet 340. This Figure 4 Shown in more detail in .

[0110] Fluid pressure is present on the upper pressure relief valve 345. On the first (outer) side of the upper pressure relief valve 345, the pressure is equal to the local water pressure (WP). For example, it will be appreciated that as the depth below sea level increases by 10 meters, the WP will increase by approximately 1 bar. On the other side of the upper pressure relief valve 345 (towards the inside of the pipe annulus), due to the presence of gas in the annulus region 180, the fluid pressure is equal to the gas (or other fluid) pressure in the annulus region 180. The gas pressure in the annulus region 180 may be referred to as the annulus pressure. The upper pressure relief valve 345 has a threshold pressure differential. At this threshold pressure differential, the linear spring will be compressed, and the pressure relief valve will open, allowing the higher pressure annulus gas to escape. The threshold pressure differential is typically approximately 2 bar. It will be appreciated that, in some cases, the threshold pressure differential may be less than 2 bar. In other examples, the threshold pressure differential may be greater than 2 bar. Suitably, the pressure differential is 3 bar. Suitably, the pressure differential is between 2 bar and 10 bar. When the annular pressure (AP) is greater than the sum of the local water pressure (WP) and a threshold pressure differential, where SP can be considered the reseating pressure differential for the pressure relief valve, the upper pressure relief valve 345 will open and allow the gas in the annular region 180 to be released. Thus, at the pressure relief valve 345, the annular pressure will decrease until AP is equal to or less than the sum of WP and SP. The reseating pressure differential SP can be equal to a pressure between 0 and the threshold pressure differential. This helps provide a positive pressure differential, i.e., it ensures that AP is always greater than WP by at least SP.

[0111] exist Figure 3In FIG. 3 , there is a module 350 on the outer surface of the end fitting 320. The module 350 is mounted to the end fitting using a band that wraps around the end fitting. It should be understood that the module 350 can also be mounted to the end fitting 320 by bolting, adhering, welding, etc. It should be understood that in some alternatives, such as Figure 8 or Figure 9 In those embodiments shown, the module 350 may not be attached to the end fitting 320. The module 350 is in fluid communication with the pressure relief valve 335 and the upper pressure relief valve 345 via the fitting 360. Specifically, the module 350 is in fluid communication with the outside of the pressure relief valve 335. The fitting 360 is made of a rubber structure, optionally with reinforcements to provide pressure resistance and / or collapse resistance. It should be understood that in other alternatives, the fitting can be manufactured using different processes or made of different materials (e.g., stainless steel, etc.). The module 350 is in fluid communication with the inside of the upper pressure relief valve 345. Therefore, the annulus pressure (AP) is equal to the pressure recorded in the module 350. The module 350 has an outer shell, also referred to as an outer shell. The shell is waterproof and rigid so as to be pressure-resistant. The shell contains and supports a first pressure sensor 370 capable of measuring fluid pressure and another pressure sensor 380 capable of measuring fluid pressure. There is a through hole in the originally fluid-tight outer shell of module 350, which allows additional pressure sensors to contact the seawater surrounding module 350. Therefore, the water pressure of the local environment is in fluid communication with the sensor. Module 350 is capable of transmitting the annular pressure value (APV) received from the first pressure sensor 370 to PLSV 222. Module 350 is also capable of transmitting the received local water pressure value (WPV) to PLSV 222. APV and WPV can be collectively referred to as data. This data is wirelessly transmitted to the PLSV using a seabed ultrasonic wireless communication system. Optionally, a time value can also be recorded. It should be understood that data is transmitted to different destinations in different ways. It should also be understood that in some alternatives, the time value is included as data. It should be understood that in some alternatives, different wireless communication technologies can be used. In other alternatives, wired communication technology can be used to transmit data from module 350 to PLSV 222. In another alternative, wired communication technology can be used to transmit data from module 350 to ROV. Optionally, the annular pressure value recorded by the annular pressure sensor can be recorded or saved to a storage medium in the module 350, such as a hard drive, flash memory, etc. Optionally, the local water pressure value recorded by the local water pressure sensor can be recorded or saved to a storage medium in the module 350, such as a hard drive, flash memory, etc. Optionally, time values ​​associated with the annular pressure value and / or the local water pressure value can be recorded or saved to a storage medium in the module 350, such as a hard drive, flash memory, etc.

[0112] Figure 4Another view of the end fitting 320 is shown showing more detail of the pressure relief valve 335 protruding from the end fitting 320. The pressure relief valve 335 can be a conventional (pre-existing) pressure relief valve that is fitted to the end fitting 320. The top surface of the pressure relief valve 335 has a bleed outlet 340. Alternatively, the pressure relief valve 335 can be installed to a new flexible tube. Alternatively, the pressure relief valve 335 is a conventional bleed outlet, such as but not limited to a prior art bleed valve of the type known to be available on an end fitting or flexible tube. The adapter 410 is attached to a first generally cylindrical shape having a hollow chamber 420. The adapter includes a through hole 430, an adapter body 440, a fitting 360 and an upper pressure relief valve 345. The through hole 430 is an opening. It should be understood that in some alternatives, the adapter 410 is made of a plastic material or rubber or a non-plastic material or a combination of these materials. In Figure 4 , a pressure relief valve 335 is secured to the bottom side of the adapter 410. An upper pressure relief valve 345 is provided with a bleed outlet 340. The upper pressure relief valve 345 is secured to the adapter 410 at the other end of the adapter 410. A through hole 430 is located midway along the adapter body 440. The fitting 360 is secured in the through hole 430 by a friction fit and by sealing with epoxy to prevent leakage. In some examples, the fitting 360 is secured in the through hole using a flange, adhesive material, or the like. The fitting 360 can be sealed using an adhesive or the like. The through hole 430 provides fluid communication between the chamber 420 and the fitting 360. It should be understood that fluid communication refers to an open path for fluid flow.

[0113] Adapter 410 is retrofitted to end fitting 320 via pressure relief valve 335. During installation, adapter body 440 is frictionally secured around pressure relief valve 335. In other words, a press fit secures adapter 410 to pressure relief valve 335. Seal 450 is disposed between adapter body 440 and pressure relief valve 335. Seal 450 comprises a polymeric sealing element. It should be understood that, in some alternatives, seal 450 may comprise a metallic material, a composite material, or the like. Adapter body 440 is generally cylindrical in shape. It should be understood that, in some examples, alternative securing methods such as threads, pins, needles, etc. may be used to secure adapter 410 around pressure relief valve 335. In some examples, adapter 410 may not be attached to pressure relief valve 335. Alternatively, adapter 410 may be retrofitted to end fitting 320 using a remotely operated vehicle (ROV). Alternatively, adapter (and module) may be assembled during installation of the pipeline arrangement. Adapter 410 includes tubing 360 and upper pressure relief valve 345. Adapter 410 is constructed of rubber and has a generally cylindrical shape with a hollow chamber 420. It should be understood that adapter 410 is sometimes made of a non-plastic material or combination of materials. Pressure relief valve 335 is located at a first end of adapter 410. An upper pressure relief valve 345 is secured to adapter 410 at its other end. Adapter 410 also has a through-hole 430 located midway along its length. Tubing 360 is secured to the outer cylindrical surface of adapter 410. Through-hole 430 provides fluid communication between chamber 420 and tube 360. It should be understood that fluid communication refers to an open path for fluid flow.

[0114] Adapter 410 is retrofitted onto end fitting 320 with protruding pressure relief valve 335. During installation, adapter body 440 is secured around pressure relief valve 335 by friction. In other words, a press fit holds adapter 410 to pressure relief valve 335. Seal 450 is disposed between adapter body 440 and pressure relief valve 335. Seal 450 comprises a polymeric sealing element. It should be understood that seal 450 may comprise a metallic material, a composite material, etc. Adapter body 440 is generally cylindrical in shape. It should be understood that alternative securing methods, such as threads, pins, needles, etc., may sometimes be used to hold adapter 410 around pressure relief valve 335. In some examples, adapter 410 may not be attached to pressure relief valve 335.

[0115] When underwater, upper pressure relief valve 345 is in contact with water. Therefore, outlet 345 is exposed to the local water pressure. Annular pressure from the gas in annular region 180 is transmitted through pressure relief valve 335 to chamber 420. Therefore, the inside of upper pressure relief valve 345 is exposed to annular pressure. Annular gas also enters tubular 360, so the pressure in tubular 360 equals the annular pressure.

[0116] exist Figure 5 , the pipeline arrangement 200 is shown being retrieved by a pipelay support vessel (PLSV) 222. During retrieval of the pipeline arrangement 200, each flexible pipe is lifted through the water towards the PLSV. Figure 2 A similar arrangement can be shown in . An end-to-end connector 510 is shown; the end-to-end connector 510 includes a pair of end fittings 320 fixed together in an end-to-end configuration. The end fitting 320 of each connector (the end fitting that is located lower in the water / farthest from the lifting point in the pair of end fittings) includes a pressure relief valve 345, an adapter 410 and a module 350. By connecting multiple flexible tubes 2401, 2402, etc. in this manner, a pipeline arrangement 200 is assembled / formed. When the flexible tubes 240 in the pipeline arrangement 200 are retracted, they are wound onto a spool (not shown) on the PLSV. Appropriately, a corresponding spool is used for each flexible tube of the pipeline arrangement. Thus, the flexible tube 240 is withdrawn from its stationary position in the sea to the PLSV. Therefore, the rotation speed of the spool determines the flexible tube retraction speed of the pipeline arrangement 200. The flexible tube retraction speed can be the flexible tube retraction rate. As previously mentioned with respect to the prior art, there is a safety limit to the flexible pipe retraction speed, above which the flexible pipe body may burst: as the flexible pipe body is raised closer to sea level, the local water pressure decreases. The local water pressure decreases at a rate of approximately 1 bar per 10 meters of depth lost below sea level. If the pressure in the annulus region 180 (annulus pressure) exceeds the local water pressure by an amount greater than the pressure limit of the outer jacket 170, the outer jacket 170 of the flexible pipe body is susceptible to bursting. Consequently, the outer jacket 170 will burst due to the excessive internal pressure. When the annulus pressure exceeds a predetermined local water pressure value, the bleed outlet 340 in the pressure relief valve 335 helps reduce the annulus pressure. The bleed outlet 340 has a maximum output rate at which it can discharge fluid, thereby discharging the annular gas into the seawater. If the flexible pipe retraction speed is too high, there is a risk that the local water pressure will decrease too quickly, and as a result, excessive internal pressure will accumulate and the outer jacket 170 will burst. In other words, the flexible tubing retraction rate is sometimes affected by the rate at which the pressure relief valve 335 is able to reduce the annulus pressure.

[0117] Certain embodiments of the present invention help eliminate such risks. It will be appreciated that the flexible tube retraction speed can be constant. In some alternatives, the flexible tube retraction speed can be variable. In other words, in some examples, the flexible tube retraction speed can be continuously variable. In the context of the flexible tube retraction speed, continuously means that the variable can change every millisecond, or every second, or every minute, or every hour, or periodically, or repeatedly, or at a given period, and so on.

[0118] The maximum feasible retraction speed is used to ensure that the outer jacket 170 does not burst due to excessive pressure in the annulus region 180. For example, when the annulus pressure reaches a dangerous level and must be reduced, the flexible tubing retraction speed is set so that it does not exceed the maximum rate at which the pressure relief valve 335 can reduce the annulus pressure. The flexible tubing retraction speed can be continuously varied. The maximum feasible retraction speed may also be referred to as the maximum feasible retraction rate. The maximum feasible retraction speed is determined according to the following formula:

[0119] AP <WP+SM 1

[0120] Where AP is the annulus pressure, WP is the local water pressure, and SM is the safety margin. AP is determined near the pressure relief valve 335. In other words, AP is measured near the pressure relief valve 335 using the first pressure sensor 370 by introducing a fluid connection between the pressure relief valve 335 and the sensor 370. In other words, a fluid connection exists between the bleed outlet 340 and the sensor 370. Suitably, the WP value is determined within a distance of 0.5 m from the bleed valve. Suitably, the distance is within 2 m. Suitably, the WP value is within a distance of 20 m from the bleed valve. The AP value (APV) is recorded by the first pressure sensor 370. It should be understood that in some examples, AP can be measured through a direct fluid connection to the annulus region 180 of the flexible pipe body. In some examples, the first pressure sensor 370 can sense pressures in the order of 0 bar to 300 bar or more. The local water pressure (WP) is the measured value of WP recorded by another pressure sensor 380 in the area near the bleed outlet. For example, in some examples, the other pressure sensor 380 is less than approximately 5 meters from the bleed outlet, and optionally, the other pressure sensor 380 is less than approximately 1 meter from the bleed outlet. In some examples, the other pressure sensor 380 can sense pressures ranging from 0 bar to 300 bar or more. The WP value (WPV) is recorded by the other pressure sensor 380. The safety margin SM is a predetermined additional pressure value. In other words, SM can be set to any pressure value by a human operator. In some examples, SM can be set to any pressure value by a computer program. In other examples, SM can be set to a pressure value by a human operator or a computer program. In this embodiment, SM is at least 2 bar. It should be understood that in some cases, SM can be at least 3 bar, at least 4 bar, etc. Optionally, SM can include the valve opening pressure (VCP). In other words, SM can optionally be the sum of a threshold pressure difference between the first side of the pressure relief valve 335 and the other side of the pressure relief valve 335 and another pressure value.

[0121] It should be understood that in some examples, Formula 1 may alternatively be:

[0122] AP <WP±SM

[0123] Where AP is the annulus pressure near the bleed outlet, WP is the local water pressure near the bleed outlet 340, and SM is a predetermined safety margin that can be positive or negative.

[0124] The annulus pressure value (APV) recorded by the first pressure sensor 370 is transmitted by module 350 to the PLSV 222. In other words, the APV is sent to the PLSV via the subsea ultrasonic wireless communication 520. The subsea ultrasonic wireless communication 520 is transmitted by a subsea ultrasonic wireless system (not shown). The subsea ultrasonic wireless system is included in module 350. The local water pressure value (WPV) recorded by another pressure sensor 380 is transmitted by module 350 to the PLSV 222. In other words, the WPV is sent to the PLSV 222 via the subsea ultrasonic wireless communication 520. It should be understood that in some alternative examples, wireless communication using sound frequencies below 20 kHz, visible light, microwaves, infrared rays, ultraviolet rays, etc. can be used to transmit the APV, WPV, APV and WPV, or other sensors or sensor-related data.

[0125] The maximum feasible retrieval speed is determined using data transmitted from module 350 associated with the end fitting 320. In Figure 5 the illustrated pipeline device 200, the maximum feasible retrieval speed is calculated once every millisecond using the above formula 1. Optionally, the calculation frequency of the maximum feasible retrieval speed can be higher than once every millisecond. In other examples, the calculation frequency of the maximum feasible retrieval speed can be lower than once every millisecond, for example, once every 1 second, once every 10 seconds, once every minute, once every 10 minutes, once every hour, etc. During pipeline retrieval, the maximum feasible retrieval speed is initially set to 1 meter per hour. Then, when the maximum feasible retrieval speed is recalculated after one millisecond, if the formula AP < WP + SM (true) is still satisfied, the maximum feasible retrieval speed is incremented by 1 meter per hour. The maximum feasible retrieval speed is recalculated every millisecond. When the maximum feasible retrieval speed is recalculated after one millisecond, if the formula AP < WP + SM (false) is not satisfied, the maximum feasible retrieval speed is decremented by 1 meter per hour. In other words, the maximum feasible retrieval speed is adjusted according to whether the formula is satisfied. Optionally, the maximum feasible retrieval speed can be incremented by 0.1 meter per hour, or 10 meters per hour, or 30 meters per hour, etc. Similarly, it should be understood that in some examples, the maximum feasible retrieval speed can be decremented by 0.1 meter per hour, or 10 meters per hour, or 30 meters per hour, etc. Then, the flexible pipe retrieval speed is continuously set to the maximum feasible retrieval speed. Here, continuous means adjusted every millisecond, every second, or every minute, etc.

[0126] Alternatively, determining the speed to be used can be done when an event occurs, rather than at regular repetitive times. It should be understood that sometimes, a feedback control system can be used to assist in setting and changing the maximum feasible retrieval speed, the flexible pipe retrieval speed, or both. It should be understood that other methods can be used to set or determine the maximum feasible retrieval speed.

[0127] It will be appreciated that in some examples, additional data, such as the maximum flow rate of the pressure relief valve 335, further data derived from the WPV, further data derived from the APV, etc., may be used to determine the flexible tube retraction speed. Alternatively, the rate of change of the APV may be calculated based on the most recent APV. Alternatively, the rate of change of the WPV may be calculated based on the most recent WPV. The maximum feasible retraction speed may be determined by estimation using the SP, APV, WPV, rate of change of the APV, and rate of change of the WPV.

[0128] Alternatively, determining the maximum feasible retrieval speed may involve any of the following steps: initially, setting the maximum feasible retrieval speed to 1 m / h, or 2 m / h, or 10 m / h, or 100 m / h, or greater; monitoring the annular pressure and / or local water pressure every millisecond, or every microsecond, or every second, or every minute, etc., during the retrieval of the pipe; wherein, during the monitoring period, if the rate of decrease per unit time of AP during the retrieval (the decrease in the rate of change of AP) is slower than the rate of decrease per unit time of WP during the retrieval (the decrease in the rate of change of WP), then the maximum feasible retrieval speed is reduced by 1 m / h; m / h, or 2 m / h, or 10 m / h, or 100 m / h or more; or wherein, during the monitoring period, if the rate of decrease of AP per unit time during retraction (decrease of AP rate of change) is equal to or higher than the rate of decrease of WP per unit time during retraction (decrease of WP rate of change), the maximum feasible retraction speed is increased by 1 m / h, or 2 m / h, or 10 m / h, or 100 m / h or more; it will be understood that the unit time may be long enough to allow sufficient pressure to build up to cause the relief valve on the flexible pipe to open at least once between monitoring intervals.

[0129] Figure 6 Shown according to Figures 1 to 5 Flowchart of flexible tube and conduit arrangement and flexible tube retraction process 600 for deflation outlet shown. It should be understood that in alternative examples, such as Figures 7 to 11 In the illustrated example, the flexible pipe retrieval process 600 will remain substantially the same, but any modifications may be made as detailed in alternative examples. In a first step S601, the pipelay support vessel 222 is positioned at sea level near the pipeline installation 200. The pipeline installation 200 is located at its subsea location prior to retrieval. That is, in S601, the pipeline installation 200, including the flexible pipes 2401 to 2406, is at its installed location (possibly many years ago).

[0130] In step S605, the module 350 and the adapter 410 are installed on the selected end fitting 320 of the flexible pipe 240 in the pipeline arrangement 200. The adapter 410 is fixed to the pressure relief valve 335 protruding from the end fitting 320. This can be achieved by an ROV or a diver, etc., depending on the water depth and other environmental factors. For each flexible pipe in the pipeline arrangement 200, a fluid connection is established between the annulus region 180 of the flexible pipe 240 and the module 350 via the fitting 360. The first hydrostatic pressure sensor 370 is exposed to the annulus pressure (AP). The other hydrostatic pressure sensor 380 is exposed to the local water pressure (WP) near the end fitting 320. The first hydrostatic pressure sensor 370 outputs data in the form of an annulus pressure value (APV). The other hydrostatic pressure sensor 380 outputs data in the form of a local water pressure value (WPV). As Figure 5 As shown, data is transmitted from the module 350 on the end fitting 320 to the PLSV 222. It should be understood that in some alternatives, the data can be transmitted from the module 350 to the PLSV 222 using wired communication, an ROV, alternative wireless communication, etc. In some cases, step S605 may involve inserting a probe into the end fitting 320. Thus, fluid communication is established between the annulus region 180 of the flexible pipe 240 and the module 350. In some cases, the module 350 may not be installed on the end fitting 320.

[0131] In step S610, a method for recovering an underwater flexible pipe is initiated. One end of the pipe arrangement 200, i.e., one end of the first flexible pipe 2401 in the pipe arrangement, is secured and lifted toward the PLSV. In other words, one end of the flexible pipe 2401 is pushed toward the PLSV. A remotely operated vehicle (ROV) is used to access one end of the first flexible pipe 2401. The ROV attaches a cable to the end fitting 320 on the first flexible pipe 2401 in the pipe arrangement 200. Thus, the pipe arrangement 200 is lifted through the water toward the PLSV 222. It should be understood that alternative methods may sometimes be used to recover one end of the pipe arrangement 200. In step S615, the rotation of the spool is stopped, thereby stopping pipe recovery, while the end fitting 320 of the first flexible pipe 2401 of the pipe arrangement 200 is removed and / or the first flexible pipe 2401 is secured to the spool. The spool is located on the PLSV. The spool is a reel used to hold a flexible pipe body with a diameter of at least 2m. It will be appreciated that in some cases the diameter of the spool may be 1 m, 3 m, 5 m etc.

[0132] In step S620, the spool resumes rotation. In other words, flexible tube retraction is restarted. It should be understood that the vertical movement of the flexible tubes in the piping arrangement may be discontinuous. While the flexible tubes are being lifted, the flexible tube retraction speed will be non-zero; when the end fittings of the flexible tubes are lifted out of the water, the flexible tube retraction speed will temporarily be zero. Once the first flexible tube 2401 has been retracted, the next flexible tube 2402 is retracted onto the second spool in the same manner as described in step S615. This process continues for the remaining flexible tubes 2403, 2504, and so on. The spool is rotated by a motor, which causes the spool to rotate at a rotational speed. In some examples, the rotational speed may be measured in revolutions per hour. It should be understood that other units of rotational speed, such as revolutions per minute, radians per second, etc., may also be used. Rotation of the spool secured to the first flexible tube 2401 causes the first flexible tube 2401 to be lifted toward the PLSV 222. Consequently, the remaining length of the piping arrangement 200 is also lifted toward the PLSV 222. The rate at which the end region of the first flexible pipe 2401 is lifted is referred to as the flexible pipe retraction speed. It should be understood that when the end region of the flexible pipe is considered, the remaining flexible pipes 2401 in the piping arrangement 200 are 3,4,5,6 The lifting rate will also be referred to as the flexible tube retraction speed. Therefore, the flexible tube retraction speed is selected by the rotational speed of the spool, which is determined by the rotational speed of the motor. It should be understood that the flexible tube retraction speed is also affected by external factors such as water flow, changes in the weight of the pipe arrangement 200 when it is lifted, etc. The rotational speed of the motor is regulated by a computer program. Alternatively, a user / operator at the PLSV or a remote location can obtain a visual data readout and manually set performance parameters (such as the spool rotational speed). Alternatively, the rotational speed of the motor can be adjusted by a manual operator. In step S620, the initial maximum possible retraction speed is set to 1 meter / hour. The initial flexible tube retraction speed is set to 1 meter / hour. It should be understood that in some examples, a feedback control system is used to help maintain the flexible tube retraction speed at a set value. In other words, the motor rotating the spool is set to a rotational speed that initially results in a flexible tube retraction speed of 1 meter / hour. It should be understood that in some examples, a different initial maximum possible retraction speed may be used.

[0133] During the lifting of the end region of the flexible pipe 2401, in step S625, data including annular pressure values ​​(APV) and local water pressure values ​​(WPV) are transmitted from the module 350 to the PLSV 222. Specifically, the data is received by the computer system on the PLSV 222. The computer system on the PLSV continuously monitors the APV received from the module 350. The computer system on the PLSV continuously monitors the WPV received from the module 350. Here, continuously means that the APV and WPV are checked every microsecond (μS) to determine whether action should be taken. It should be understood that in some examples, continuously can refer to every millisecond, every second, every minute, every hour, etc. The values ​​of the annular pressure (AP) and the local water pressure (WP) are monitored according to the following formula:

[0134] AP <WP+SM 1

[0135] Where AP is the annular pressure near the bleed outlet, WP is the local water pressure near the bleed outlet 340, and SM is a predetermined safety margin. It should be understood that in some examples, the APV and / or WPV are monitored by a human operator. In step S625, a logical value of TRUE or FALSE is assigned to the equation based on the latest APV and WPV. In other words, the AP and WP recorded by sensors 370 and 380 are used to determine whether the equation is true or false.

[0136] In step S630, the computer system detects that the equation is true. In other words, WP + SM is greater than AP. In this case, the maximum possible retraction speed is incremented by 1 m / h. Alternatively, the maximum possible retraction speed can be incremented by 0.005 m / h, 0.1 m / h, 2 m / h, 10 m / h, 100 m / h, and so on.

[0137] In step S635, the flexible tube retraction speed is set to a value within 10 m / h below the new maximum possible retraction speed. Alternatively, the flexible tube retraction speed may be set to a value within 20 m / h, 50 m / h, etc. below the new maximum possible retraction speed. It will be appreciated that in some examples, a feedback control system is used to help maintain the flexible tube retraction speed at the set value.

[0138] The method will then return to step S625 and continue to monitor APV and WPV again after 1 μ8. As previously discussed, it will be appreciated that in some examples, the time delay between repeated monitoring of data including APV and WPV may be different.

[0139] In step S640, the computer system detects that the equation is false. In other words, WP + SM is less than AP. In this case, the maximum possible retraction speed is decremented (reduced) by 1 m / h. It should be understood that the maximum possible retraction speed can be decremented by 0.005 m / h, 0.1 m / h, 2 m / h, 10 m / h, 100 m / h, etc.

[0140] In step S645, the flexible tube retraction speed is set to a value within 10 m / h below the new maximum possible retraction speed. It will be appreciated that the flexible tube retraction speed may be set to a value within 20 m / h, 50 m / h, etc. below the new maximum possible retraction speed. A feedback control system may be employed to help maintain the flexible tube retraction speed at the set value. The method then returns to step S625 and, after 1 μS, the APV and WPV are again continuously monitored. As previously discussed, it will be appreciated that in some examples, the time delay between repeated monitoring of data including the APV and WPV may vary.

[0141] The method will then return to step S625 and continue to monitor APV and WPV again after 1 μ8. As previously discussed, it will be appreciated that sometimes the time delay between repeated monitoring of data including APV and WPV may be different.

[0142] Figure 7 An alternative example of an adapter 410 secured to the pressure relief valve 335 of the end fitting 320 is shown. Figure 7 The adapter 410 has a chamber 420, a through hole 430, an upper pressure relief valve 345, a pipe 360 ​​and an adapter body 440. The adapter body 440 has Figure 4 An alternative shape to the shape shown. Adapter 410 is constructed of rubber and has a generally cylindrical shape with a hollow interior containing chamber 420. It should be understood that adapter 410 can be made of non-plastic materials or a combination of materials. Adapter body 440 is constructed of a cylindrical body and a wide collar 720 located at one end of the cylindrical body. The wide collar 720 has a larger diameter than the cylindrical body. The wide collar 720 contacts the end fitting 320.

[0143] The adapter 410 is installed on the pressure relief valve 335 protruding from the end fitting 320. During installation, the adapter body 440 is secured around the pressure relief valve 335 by friction. In other words, a press fit holds the adapter 410 on the pressure relief valve 335. A seal 730 is disposed between the adapter body 440 and the pressure relief valve 335. The seal 730 comprises a polymeric sealing element. It should be understood that in some examples, the seal 730 may comprise a metallic material, a composite material, etc. It should be understood that in some examples, alternative securing methods such as threads, pins, needles, etc. may be used to hold the adapter 410 around the pressure relief valve 335. In some examples, the adapter 410 may not be attached to the pressure relief valve 335. In some examples, the wide collar 720 may be a flange that is secured into the end fitting 320 using bolts.

[0144] Figure 8 FIG. 2 shows a pipe arrangement 200 according to an alternative example. The pipe arrangement 200 may be similar to Figure 2 The arrangement in FIG. The pipeline arrangement 200 includes flexible pipes 2401 to 2406; an end-to-end connector 510 including an end fitting 320 of a lower flexible pipe 2402 secured to an end fitting 320 of an upper flexible pipe 2401; a pipelay support vessel (PLSV) 222; and a remotely operated vehicle (ROV) 810. The ROV 810 is a waterproof vehicle that can be operated from the PLSV 222. In other words, power and data are transmitted from the PLSV 222 to the ROV 810 via the long-distance cable 820. It should be understood that in some cases, the ROV 810 can communicate wirelessly with the PLSV 222 and be powered by a portable power source such as a battery.

[0145] The end-to-end connection 510 includes an end fitting 320. The end fitting 320 includes a pressure relief valve 335, an adapter 410, and a module 350, such as Figure 3 and Figure 4 As described in Figure 8 Module 350 is shown wirelessly transmitting data, including annular pressure values ​​(APV) and local water pressure values ​​(WPV). The APV and WPV are received by ROV 810. In other words, data is wirelessly transmitted 830 from module 350 to ROV 810 using a modem. It should be understood that different communication methods may be used to wirelessly transmit data from module 350 to ROV 810 via wireless protocol 830. In some cases, module 350 may display the APV on a display, which may be read by a camera on ROV 810. In some embodiments, module 350 may display the WPV on a display, which may be read by a camera on ROV 810.

[0146] Figure 9An alternative embodiment is shown. The lower flexible tube 2402 is attached to the upper flexible tube 2401 via an end-to-end connector 510. As previously described, the pressure relief valve 335 is attached to the end fitting 320. Additionally, the adapter 410, including the upper pressure relief valve 345, is secured to the pressure relief valve 335. The fitting 360 provides a fluid connection between the adapter 410 and the module 350. Figure 9 In FIG, module 350 is located on ROV 810. The ROV is connected to PLSV 222 via a long distance cable 820.

[0147] Adapter 410 is installed on pressure relief valve 335 via ROV 810. A first pressure sensor 370 detects annular pressure (AP) from the annulus of flexible pipe 240 via tubular 360. Another pressure sensor 380 detects local water pressure (WP) near end fitting 320. In other words, module 350, located on ROV 810, is located near end fitting 320. The annular pressure value (APV) is transmitted from first pressure sensor 370 to module 350, ROV 810, and then to PLSV 222 via long-distance cable 820. Similarly, the local water pressure value (WPV) is transmitted from first pressure sensor 370 to module 350, ROV 810, and then to PLSV 222 via long-distance cable 820. In other words, data including the APV and WPV values ​​is transmitted via ROV 810 to PLSV 222.

[0148] Figure 10 and Figure 11 An alternative example of a flexible pipe 240 is shown. The flexible pipe 240 comprises an end fitting 320 and a flexible pipe body 100. From innermost to outermost, the flexible pipe body 100 comprises: an inner pressure jacket 110, an annulus region 180 and an outer jacket 170. Figure 10 and Figure 11 The flexible pipe body 100 has a smooth bore. The annulus region 180 includes a pressure armor layer 130, a first tensile armor layer 140, and an additional tensile armor layer 150. It should be understood that other layers may be present in the annulus region 180. The end fitting 320 is generally cylindrical in shape, e.g., Figure 3 and Figure 9 As shown. Figure 10 and Figure 11In the illustrated end fitting 320, the bleed outlet 340 is an opening that is not part of the pressure relief valve 335. The bleed outlet 340 is recessed into the body of the end fitting 320. It should be understood that the bleed outlet 340 can be referred to as a bleed valve. The end fitting 320 has two fill ports: a first fill port 10101 sealed with epoxy and a second fill port 10102. It should be understood that the fill ports 1010 can be made of different materials, such as any polymer. It should be understood that in some cases, there may be only one fill port 1010 in the end fitting. In other examples, there may be more than two fill ports 1010 in the end fitting 320.

[0149] The flexible pipe body 100 is attached to the end fitting 320 by separating the layers of the flexible pipe body 100 at the end of the flexible pipe body and securing the layers to the end fitting 320. The internal pressure sheath 110 terminates in the first gripping area 1020 and is held in place therein by a friction fit. In the first gripping area 1020, the internal pressure sheath 110 is clamped between the first half of the end fitting 320 and the other half of the end fitting 320. Thus, fluid is prevented from leaking from the interior of the internal pressure sheath 110 into the annulus region 180. The pressure armor layer 130 is terminated independently of the remaining layers in the annulus region 180. The outer sheath 170 terminates in a further gripping area 1050 and is held in place therein by a friction fit. Thus, fluid is prevented from leaking from the outside of the outer sheath 170 into the annulus region 180. Consequently, the annulus region 180 is sealed from fluid ingress from both sides. The epoxy shell 1060 in the end fitting 320 fills the open space into which the layers of the annulus area 180 terminate. The epoxy shell 1060 is filled by pumping epoxy into the first fill port 10101. Excess epoxy is purged through the second fill port 10102. Once the epoxy has hardened within the end fitting 320, the vent column 1070 is opened by drilling through the epoxy. Gas in the annulus area 180 is able to enter the vent column 1070. Gas in the vent column 1070 can be exhausted through the bleed outlet 340. Figure 10 In the end fitting 320 in FIG, the bleed outlet 340 may be configured as a back-end vent system 1080. It will be appreciated that some end fittings 320 may have more than one bleed outlet 340. Through the vent post 1070, the annulus gas is also able to reach the fill port 1010. The fill port 1010 is sealed; that is, gas from the annulus region 180 cannot pass through the fill port 1010 because the fill port 1010 is sealed by a suitable sealing plug. Figure 6In an alternative to step S605 in the embodiment of the present invention, a probe can be used to pierce the bleed outlet 340 and thereby measure the annular pressure. In other words, a probe can be used to form a hole in the bleed outlet 340. In some examples, the probe is connected to the tubing 360 of the adapter 410. As a result, annular gas can be transferred from the annular region of the flexible pipe body 100 to the module 350. In other words, the bleed outlet 340 can provide fluid communication with the module 350.

[0150] Figure 11 An alternative version of the end fitting 320 is shown. Figure 11 1060. In the embodiment shown in FIG. 1061, the bleed outlet 340 in the end fitting 320 is in the front end exhaust system configuration 1110. The annulus gas from the annulus region 180 passes through the bleed outlet 340 in the exhaust pipe 1120 to the module 350. The exhaust pipe 1120 is a stainless steel pipe that connects the annulus region 180 to the bleed outlet 340. The exhaust pipe 1120 is surrounded by a hardened epoxy resin in the epoxy resin shell 1060. It should be understood that the exhaust pipe 1120 can alternatively be made of any alloy, composite material, polymer, etc.

[0151] Throughout the detailed description and claims of this specification, the words "comprise" and "comprising" and their variations mean "including but not limited to", and they are not intended to (and do not) exclude other parts, additives, components, integers or steps. Throughout the detailed description and claims of this specification, the singular encompasses the plural unless the context requires otherwise. In particular, where the indefinite article is used, the specification should be understood as contemplating plurality as well as singularity unless the context requires otherwise.

[0152] Features, integers, features or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All features disclosed in this specification (including any accompanying claims, abstract and drawings) and / or all steps of any method or process so disclosed may be combined in any combination, except that at least some of the features and / or steps are mutually exclusive combinations. The invention is not limited to any details of any foregoing embodiments. The invention extends to any novel feature or novel combination of features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel step or novel combination of steps of any method or process so disclosed.

[0153] The reader's attention is directed to all papers and documents filed in connection with this patent application concurrently with or before this specification and which disclose public inspection of this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

1. A method for retrieving an underwater flexible pipe, comprising: pushing an end region of the flexible pipe toward the floating platform at a flexible pipe retraction speed, thereby lifting the flexible pipe through the water; determining a relationship between an annulus pressure in an annulus region of the flexible pipe and a local water pressure proximate at least one bleed outlet on an end fitting of the flexible pipe as the flexible pipe is lifted; as well as The flexible tube retraction speed is selected responsive to the relationship.

2. The method according to claim 1, further comprising: Said step of selecting said retraction speed comprises repeatedly determining a maximum feasible retraction speed; as well as The flexible pipe retraction speed is set at or within 10 m / h below the maximum possible retraction speed.

3. The method according to claim 1 or claim 2, further comprising: The flexible tube retraction speed is selected according to the following formula: AP <WP+SM Where AP is the annulus pressure close to the bleed outlet, WP is the local water pressure close to the bleed outlet, and SM is a predetermined safety margin.

4. The method according to claim 3, wherein: The predetermined safety margin is at least 2 bar, and optionally at least 3 bar.

5. The method according to claim 3 or claim 4, further comprising: repeatedly measuring an annulus pressure (AP) proximate the bleed outlet and repeatedly determining a local water pressure (WP) proximate the bleed outlet while the flexible pipe is being lifted; as well as In response thereto, the rate of change of the annular pressure and the rate of change of the water pressure are determined.

6. The method according to any one of claims 1 to 5, further comprising: securing a module comprising a housing containing an annulus pressure sensor and a local water pressure sensor to the end fitting; as well as A corresponding fluid communication passage in fluid communication with the annulus pressure sensor is secured between the housing and the bleed outlet.

7. The method according to claim 6, further comprising: communicating the local water pressure to the local water pressure sensor via a water pressure port in the housing and a corresponding further fluid communication path between the water pressure port and the local water pressure sensor; and Annulus pressure is communicated to the annulus pressure sensor via the first fluid communication passage.

8. The method according to claim 6 or claim 7, further comprising: Annular pressure values ​​and local ambient water pressure values ​​are wirelessly transmitted from the module.

9. The method according to any one of claims 1 to 5, further comprising: A first fluid communication passage in fluid communication with an annulus pressure sensor located on a remotely operated vehicle (ROV) is secured to the bleed outlet. The ROV also includes a local water pressure sensor.

10. The method according to claim 8 or claim 9, further comprising: Wireless communication occurs by transmitting ultrasound signals from an ultrasound modem in the module, or by transmitting light from one or more light emitting elements on the housing, or by wirelessly transmitting wireless signals from an ROV adjacent to the module.

11. Apparatus for providing data during a flexible pipe retrieval process of an underwater flexible pipe, comprising: an annulus connection member comprising a housing connectable to a bleed outlet of an end fitting of a flexible pipe; as well as A fluid communication passage has a first end connected to the annulus connection member and in fluid communication with the annulus connection member, and another end connected to an annulus pressure sensor located in the waterproof housing and in fluid communication with the annulus pressure sensor.

12. The apparatus according to claim 11, further comprising: The annulus connection member comprises a rigid body having a first body end region comprising a bleed valve and a bleed hole and a further body end region comprising a fixing element for fixing to an orifice of the bleed outlet.

13. The apparatus according to claim 11 or claim 12, further comprising: A module includes the waterproof housing and the annulus pressure sensor, and further includes a water pressure port including an opening in the housing and the fluid communication passage extending between the opening and the water pressure sensor in the housing.

14. The apparatus according to claim 13, further comprising: A wireless modem includes a transmitter element for transmitting annular pressure values ​​and local water pressure values.

15. The apparatus of claim 13, further comprising: A storage medium is used to record a plurality of annular space pressure values, local water pressure values, and time values ​​associated with the annular space pressure values ​​and the local water pressure values.

16. The apparatus of claim 11 or claim 12, further comprising: A remotely operated vehicle (ROV) includes the waterproof housing and the annulus pressure sensor, and also includes a water pressure port, the water pressure port including a through opening located in an outer wall of the ROV and a fluid communication channel extending between the opening and the water pressure sensor in the housing of the ROV.

17. The apparatus according to claim 16, further comprising: A wireless modem includes a transmitter element for transmitting annular pressure values ​​and local water pressure values.

18. The apparatus of claim 16, further comprising: The fixing element comprises a piercing element for fixing to the orifice of the deflation outlet.

19. A method for retrieving a submarine pipeline device, comprising: advancing a flexible tube end portion of each of a plurality of flexible tubes of a piping arrangement individually toward a surface platform, thereby lifting the piping arrangement through the water, the piping arrangement comprising a plurality of flexible tubes arranged in an end-to-end configuration; and As the flexible pipe of the piping arrangement is lifted, a flexible pipe retraction speed is varied in response to the environmental control pressure in the environmental control zone of the current uppermost flexible pipe of the piping arrangement to maintain at least a predetermined average flexible pipe retraction speed of the piping arrangement.

20. The method according to claim 19, further comprising: The flexible tube retraction speed is also varied in response to local water pressure proximate the currently uppermost flexible tube of the conduit arrangement.

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