Modification of components

Abstract

A method and apparatus for modifying a composition of an annulus fluid in at least one annulus region of a flexible pipe and a flexible pipe are disclosed. The method includes providing at least one alert signal indicating that a predetermined condition associated with an annulus region in a flexible pipe body of the flexible pipe is satisfied; actuating, in response to each alarm signal, at least one pump element selectively in fluid communication with a plurality of containers each containing a respective source of a respective cancellation fluid that cancels a respective predetermined fluid condition; and providing at least one counteracting fluid into the annulus region, thereby modifying a composition of the annulus fluid in the annulus region.

Description

[0001] The present invention relates to a method and apparatus for modifying the composition of annulus fluid in at least one annulus region of a flexible pipe. In particular, but not exclusively, the present invention relates to providing a plurality of fluid sources each having a respective counteracting effect on fluid pooled in an annulus region of a flexible pipe. By monitoring the annulus region, the respective counteracting fluid can be selectively introduced into the annulus region in an automated and real-time manner to continuously modify the composition of the annulus fluid in the annulus region to help minimise any undesirable effects caused by migration of gas through the fluid retention layer or damage to the outer sheath.

[0002] Flexible pipes are widely used in offshore applications in the oil and gas industry for transporting oil, gas, water or other fluids from one location to another. Flexible pipes are particularly useful in connecting a sea level support structure and a subsea location, which can be a deep water depth, such as 1000 metres or more, where the pipe can act as a riser. Flexible pipes are typically formed as an assembly of a flexible pipe body and one or more end fittings. The flexible pipe body can have an internal diameter, typically up to about 0.6 metres (e.g. the diameter can be in the range 0.05 m up to 0.6 m). Due to their location, flexible pipes are exposed to a range of challenging conditions which can have high pressure, sea water, high tensile strain and corrosive environments. As such, the flexible pipe body is constructed from a number of concentric polymer, metal and / or composite layers. For example, the pipe body can comprise polymer and metal layers, or polymer and composite layers, or polymer, metal and composite layers. The layers can be formed from a single piece, such as an extruded tube, or by helically winding one or more wires at a desired pitch, or by joining together a plurality of discrete rings arranged concentrically side by side. Depending on the layers of flexible pipe used and the type of flexible pipe, some of the pipe layers can be bonded together or remain unbonded. The polymer layers generally provide a seal against ingress of fluid and the metal layer structure rigidity.

[0003] Some flexible pipes have been used in deep water (less than 3,300 feet (1,005.84 meters) and ultra-deep water (greater than 3,300 feet) developments. The increasing demand for oil has required exploration in increasingly deeper, more extreme environmental conditions (e.g., over 8,202 feet (2,500 meters)). For example, in such deep water and ultra-deep water environments, the ocean floor temperature increases the risk of production fluid cooling to a temperature that can cause the pipe to plug. In practice, flexible pipes are conventionally designed to operate at working temperatures of -30°C to +130°C, and pipe bodies for more extreme temperatures are being developed. The increased depth also increases the pressure associated with the environment in which the flexible pipe must operate. For example, it can be necessary for the flexible pipe to operate with external pressures acting on the pipe in the range of 0.1 MPa to 30 MPa. Likewise, the transport of oil, natural gas, or water can well produce high pressures acting on the flexible pipe from the inside, such as internal pressures from the bore fluid acting on the pipe in the range of zero to 140 MPa. Thus, the need for high levels of performance and environmental adaptation of certain layers of the flexible pipe body, such as the pipe carcass layer or pressure armor layer or tensile armor layer, is increased. Note that for completeness, flexible pipes can also be used in shallow water applications (e.g., depths less than about 500 meters) or even in shore (land) applications.

[0004] The innermost layer of the flexible pipe body typically includes an inner sheath, which can be an extruded, non-porous polymer layer that confines the bore fluid to its inner circumference. The outermost sealing or fluid-dense layer of the flexible pipe is typically an outer sheath, i.e., an extruded, non-porous polymer layer that protects the structural elements of the pipe from the environment surrounding the flexible pipe and prevents seawater ingress. An annulus region is defined between the radially outer surface of the inner fluid-retaining layer and the radially inner surface of the outer fluid-retaining layer.

[0005] For some flexible pipes that include an intermediate polymer layer, the flexible pipe body can include a plurality of annuli. However, for many flexible pipes, only an outer polymer layer and an inner polymer layer are included. The single annulus of such flexible pipes is thus provided as the region between the innermost fluid containment layer and the outermost fluid containment layer. The innermost layer in the main annulus region is a pressure armour layer. These pressure armour layers are made from flat wires that are helically wound with a lay angle close to 90°. Adjacent windings in the pressure armour layer interlock to control the gap between the coils. The pressure armour is designed to withstand hoop stresses in the pipe wall caused by the bore fluid pressure. Pairs of tensile armour layers can also be located in the annulus, and these tensile armour layers are cross-wound radially outward of the pressure armour layers. The tensile armour layers are typically made from slightly flattened rectangular metal wires that are arranged with a lay angle of about 30-55°. The tensile armour layers support the weight of all the internal pipe layers and transmit the resulting tensile stresses to the sea floor support structure. The annulus can also have other layers, such as tapes that resist abrasion and prevent the separation of the strands, and thermal insulation layers. The carbon steel wires in the annulus thus typically possess the characteristics of a flexible pipe for a subsea environment.

[0006] During the service life of a flexible pipe in a pipeline, gases can permeate through the various fluid retention layers and partially or completely fill one or more annulus regions defined by the various layers. In many cases, this can lead to the fact that if the annulus is not sufficiently aerated, these gases can cause damage to the outer sheath of the pipeline or corrosion of the steel layers within the annulus region. The gases that collect and their concentrations are known to vary depending on the oil and gas field in which the flexible pipe is deployed and the service life of the pipeline. From a corrosion perspective, methane, carbon dioxide, hydrogen sulphide, water and / or methanol are all fluids of interest. It has been considered to date that it is advantageous to be able to control the level of key target gases to ensure that they remain below a desired level during the operation of the flexible pipe. For example, it is an aim to control the level of corrosive gases to ensure that they remain below the upper limit of the so-called sweet regime as defined in ISO 15156. Generally, any environment in which the partial pressure of H2S is higher than 0.05 pounds per square inch absolute pressure (PSIA) is considered to be an acidic regime. Traditionally, a vent valve must be provided in the riser system or other such pipeline system, which opens when a desired differential pressure is reached. Other alternative ways of assisting in the venting or evacuation of undesirable fluids from the annulus region have been proposed.

[0007] Similarly, WO2015 / 121616 proposes an alternative method for providing a predetermined fluid in the annular void space of a flexible tube. This predetermined fluid may include water, grease, or oil, optionally with the addition of an oxygen scavenger, H2S scavenger, pH buffer, or biocide. While the solution proposed in WO2015 / 121616 works well in some cases, it is unsuitable for use in others, and its application may prove operationally difficult. A limitation of the solution proposed in WO2015 / 121616 is the requirement to pre-select a single, predetermined fluid that can be introduced into the annular region. This is disadvantageous in cases where an unexpected fluid itself is introduced into the annular void space.

[0008] Similarly, while liquid chemicals are known for their use in H2S removal, metal surface passivation, and the like, there are few or no recommendations on how to deploy these liquid chemicals in a way that optimizes the end results.

[0009] Some previous solutions have attempted to incorporate neutralizing chemicals into the inner sheath. However, their effectiveness is limited by the thickness of the inner sheath. The combination of this neutralizing chemical with specific contaminants must also be considered. Therefore, to date, there are few solutions for the problems that may arise when other unintended contaminants enter the annular region.

[0010] The object of the present invention is to at least partially alleviate one or more of the problems mentioned above.

[0011] The object of certain embodiments of the present invention is to provide a method for determining the composition of annular fluid in at least one annular region of a modified flexible tube.

[0012] The object of certain embodiments of the present invention is to provide a flexible tube and auxiliary equipment that can automatically and in real time modify the composition of the annular fluid in at least one annular region of the flexible tube.

[0013] The object of the present invention is to provide a chemical delivery system that can directly introduce a counteracting fluid when needed and can optionally be connected to an exhaust gas analysis system and / or an electronic liquid inlet detection system.

[0014] The object of certain embodiments of the present invention is to provide a method for manufacturing a flexible tube body that selectively introduces a desired fluid into one or more annular regions within the flexible tube body, whereby each introduced fluid can correspondingly counteract unwanted fluid that has already accumulated in the annular regions.

[0015] The object of certain embodiments of the present invention is to provide a system for monitoring the composition of annular fluid in the annular region of a flexible tube body during use.

[0016] The purpose of certain embodiments of the present invention is to provide the ability to inject passivating, suppressing, and / or purging chemicals and / or diluting gases into the annular region at any time and whenever any of the possible source fluids having such counteracting properties is required.

[0017] According to a first aspect of the invention, a method is provided for modifying the composition of annular fluid in at least one annular region of a flexible tube, the method comprising the steps of: providing at least one alarm signal indicating that predetermined conditions associated with an annular region in the flexible tube body of the flexible tube are met; in response to each alarm signal, actuating at least one pump element selectively in fluid communication with a plurality of containers each containing a corresponding source of a corresponding counteracting fluid, the corresponding counteracting fluid being a fluid that counteracts a corresponding predetermined fluid condition; and providing at least one counteracting fluid to the annular region, thereby modifying the composition of the annular fluid in the annular region.

[0018] Suitable, the method further includes: determining corresponding concentration levels of various target fluids in corresponding annular regions within the flexible tube body of the flexible tube; determining that at least one determined concentration level satisfies a predetermined condition indicating that the corresponding target fluid is a harmful target fluid; and changing the concentration level of at least one harmful target fluid to modify the composition of the annular fluid in the annular region.

[0019] Determining the appropriate concentration level includes determining whether the target fluid is present in a sample of annular fluid from the annular region.

[0020] Appropriately, the method further includes: if the presence of a target fluid is determined, determining the total percentage of that target fluid in the annular fluid for each harmful target fluid.

[0021] Appropriately, the method further includes: determining the corresponding concentration level via an analyzer module, the analyzer module being in fluid communication with a fluid communication channel and configured to sample and identify multiple component target fluids in the annular fluid.

[0022] Suitablely, the method further includes: modifying the composition by altering the concentration level of each of the at least one harmful target fluids in a plurality of possible injectable counteracting fluids and injecting the selected injectable counteracting fluid into at least one fluid communication channel, wherein the at least one fluid communication channel extends along a portion of the annular region and is in fluid communication with at least one region in the annular region.

[0023] Suitable, the method further includes: selecting at least one injectable counteracting fluid for each harmful target fluid; and providing injectable counteracting fluid from the corresponding counteracting fluid source into the annular region.

[0024] Suitable, the method further includes: pushing fluid at positive pressure through the pump element into the annular region via the inner cavity, the inner cavity being helically disposed in the annular region and providing a fluid communication channel along the annular region.

[0025] Appropriately, the method further includes determining that at least one concentration level satisfies a predetermined condition by simultaneously and repeatedly determining that the measurement level of each of the plurality of harmful target fluids is equal to or greater than a preset threshold.

[0026] Suitable, the method further includes providing each counteracting fluid by injecting a portion of the passivating fluid and / or the inhibiting fluid and / or the scavenging fluid into the annular region.

[0027] Suitablely, the method further includes applying a negative pressure to the annular region via a pump element, thereby selectively extracting annular fluid from the annular region.

[0028] Suitablely, actuating at least one pump element includes actuating a single pump element or actuating multiple pump elements, the single pump element being selectively in fluid communication with multiple containers, each of the multiple pump elements being selectively in fluid communication with at least one container ...

[0029] Suitable, the step of actuating multiple pump elements includes simultaneously or sequentially actuating one of the multiple pump elements to simultaneously or sequentially inject corresponding counteracting fluids into the annular region.

[0030] Providing the alarm signal appropriately includes monitoring at least one fluid parameter of at least one of the multiple target fluids.

[0031] Appropriately, the at least one fluid parameter is a plurality of fluid parameters.

[0032] Suitable, the at least one of the multiple target fluids is multiple target fluids.

[0033] Appropriately, the at least one fluid parameter is the concentration of at least one target fluid in the target fluid.

[0034] Suitablely, the method further includes providing the alarm signal when, for at least one of the plurality of target fluids, the at least one fluid parameter exceeds a first predetermined threshold, the first predetermined threshold optionally being a predetermined concentration of at least one of the plurality of target fluids in the annular region.

[0035] Appropriately, the predetermined condition is satisfied when at least one fluid parameter of at least one of the multiple target fluids exceeds a first predetermined threshold.

[0036] Suitable, the method further includes: in response to the alarm signal, providing at least one counteracting fluid to the annular region for a predetermined period of time.

[0037] Suitable, the method further includes: providing a predetermined amount (optionally, volume) of counteracting fluid in response to the alarm signal.

[0038] Suitable, the method further includes: in response to another alarm signal, providing at least one other counteracting fluid to the annular region.

[0039] Suitablely, the method further includes: providing the other alarm signal when the at least one fluid parameter (of the at least one of the plurality of target fluids) exceeds another predetermined threshold, the other predetermined threshold optionally being another predetermined concentration of the at least one of the plurality of target fluids.

[0040] Appropriately, the other predetermined threshold is numerically greater than the first predetermined threshold.

[0041] Suitable, the method further includes: in response to a stop signal, stopping the supply of the at least one counteracting fluid to the annular region.

[0042] Suitable, the method further includes providing the stop signal when the at least one fluid parameter approaches, reaches, or exceeds a predetermined stop threshold.

[0043] Appropriately, the predetermined stopping threshold is numerically greater than the first predetermined threshold.

[0044] Suitable, the method further includes: providing the at least one counteracting fluid to the annular region in response to a reactivation signal.

[0045] Suitable, the method further includes providing the reactivation signal when the at least one fluid parameter approaches, reaches, or falls below the predetermined reactivation threshold.

[0046] Appropriately, the predetermined reactivation threshold is numerically greater than the first predetermined threshold and / or (numerically) less than the predetermined stop threshold.

[0047] Appropriately, the method includes simultaneously selecting a predetermined fluid to substantially fill the void space of the annulus.

[0048] Appropriately, the method provides to substantially fill the void space of the annular region with only a single predetermined fluid, and then remove the fluid from the void space via a negative pressure pump, and subsequently reintroduce another different predetermined fluid into the void space.

[0049] Suitablely, the method includes: substantially simultaneously delivering fluid to multiple locations along the length of the flexible tube body. The delivered fluid may be a mixture of different fluids, each of which counteracts a corresponding undesirable substance, or alternatively, a single fluid selected from a plurality of injectable fluids.

[0050] Suitablely, the method further includes supplying fluid to the void space of the annular region at a flow rate of at least about 5 liters per minute and optionally at least about 15 liters per minute and optionally at least about 25 liters per minute.

[0051] Suitablely, the method provides injection of one or more predetermined fluids from multiple separate and distinct fluid sources. Optionally, the one or more predetermined fluids are injected at a positive pressure of less than or equal to about 50 PSI, or about 50 PSI, or greater than 50 PSI. Optionally, the positive pressure may be 100 PSI, 1000 PSI, 10,000 PSI, 100,000 PSI, or even higher values.

[0052] Appropriately, the method provides the injection of one or more predetermined fluids from a single fluid source.

[0053] According to a second aspect of the invention, an apparatus is provided for modifying the composition of annular fluid in at least one annular region of a flexible tube, the apparatus comprising: at least one positive pressure pump element selectively in fluid communication with a plurality of respective counteracting fluid containers for storing respective counteracting fluids; at least one alarm generator unit, each alarm generator unit being configured to provide a corresponding at least one alarm signal indicating that predetermined conditions associated with an annular region in the flexible tube body of the flexible tube are met; wherein the positive pressure pump element is actuable to selectively inject one or more fluids from the counteracting fluid containers into the annular region, thereby modifying the composition of the annular fluid in the annular region.

[0054] Appropriately, the alarm generator unit is an acoustic and / or electromagnetic monitor, or a distributed temperature sensing (DTS) sensor, or a distributed acoustic sensing (DAS) sensor, or a real-time sheath damage detection system.

[0055] Appropriately, the alarm generator unit includes a real-time sheath breakage detection (SPIRE) system or a pipeline electronic breakage locator (PEBL).

[0056] Suitablely, the at least one positive pressure pump element includes a single positive pressure pump element that is selectively in fluid communication with a plurality of containers of a corresponding counteracting fluid, or the at least one positive pressure pump includes a plurality of pump elements, each pump element being selectively in fluid communication with at least one container of a corresponding counteracting fluid.

[0057] Suitable, the at least one alarm generator includes a real-time exhaust gas monitoring system for providing output data indicating the corresponding concentration level of at least one annular fluid substance, and generating a corresponding alarm command when the concentration level is equal to or exceeds a corresponding predetermined threshold.

[0058] Appropriately, the at least one alarm generator further includes a real-time sheath damage detection system.

[0059] According to a third aspect of the invention, a flexible tube body is provided, the flexible tube body comprising: an inner fluid retention layer and another fluid retention layer, the other fluid retention layer being radially outside the inner fluid retention layer and spaced apart from the first fluid retention layer to provide an annular region therebetween; at least one conduit extending from a fluid inlet end of the flexible tube body along at least a portion of the entire length of the flexible tube body, the at least one conduit including at least one opening, each opening being disposed at a corresponding location along the length of the conduit for transferring counteracting fluid injected at a fluid injection end of the conduit into the void space in the annular region; and an end fitting terminating at the fluid inlet end of the flexible tube body, the end fitting including at least one fluid injection port, the at least one fluid injection port being connectable to the outlet of at least one positive pressure pump element.

[0060] Suitablely, the end fitting further includes at least one fluid vent port, which is connectable to a negative pressure pump element for selectively venting fluid partially or completely from the annular region; and the end fitting further includes a gas vent port.

[0061] Some embodiments of the present invention provide a method for modifying the composition of annular fluid in at least one annular region of a flexible tube. The method includes: providing an alarm signal indicating that predetermined conditions are met; actuating one or more pumps, each associated with a corresponding source of a corresponding counteracting fluid, in response to the alarm signal; and injecting one or more different counteracting fluids into the annular region, thereby modifying the composition of the annular fluid.

[0062] Some embodiments of the present invention provide an automatic and real-time monitoring and fluid introduction system for monitoring fluid accumulation in the annular region of the flexible tube body of a flexible tube over time, and selectively introducing one or more fluids once, repeatedly, intermittently, or continuously, the fluids having the ability to counteract the harmful effects caused by corresponding predetermined fluid conditions in the annular region.

[0063] Some embodiments of the present invention provide real-time exhaust gas monitoring to monitor the concentration of gaseous substances in the annulus region of a flexible tube. The monitored gaseous substances can be one, two, three, or more, each associated with a gas that may cause harmful effects over time. For example, this includes gaseous substances that may cause stress corrosion cracking. Monitoring the evolution of gaseous substances within the annulus of the flexible tube over time can occur within a portion or the entire service life.

[0064] Some embodiments of the present invention provide a gas monitoring system that measures flow rate and pressure, as well as other parameters of such annular regions, and concentrations of gases such as carbon dioxide, methane, hydrogen sulfide, and oxygen in the annulus. Continuous real-time data can be continuously measured and stored so that the gas can be analyzed under in-situ conditions. Intermittent and / or scheduled data acquisition routines can also be employed, and measurements can be similarly stored so that the annular gas can be analyzed under in-situ conditions.

[0065] Certain embodiments of the present invention provide very useful information when exploiting oil and gas fields containing corrosive gases or prone to well acidizing. A system is provided that is either a multiplexing system or a single dedicated system. The multiplexing system can be connected to multiple flexible pipes, such as multiple risers, multiple riser segments, or alternatively, the system can be dedicated in the sense that it is in fluid communication only with a single annulus region of a single flexible pipe.

[0066] Certain embodiments of the present invention provide annular fluid analysis on a continuous and real-time basis, eliminating the need for human operators to monitor the evolution of gaseous substances throughout a portion or all of the system's lifespan. The system can be automated in the sense of automated monitoring of gaseous substances and the controllable injection of multiple optional fluid substances, each with corresponding counteracting properties against one or more undesirable gaseous substances in the annular region.

[0067] Certain embodiments of the present invention provide for monitoring annular fluid over time periods of hours, months, or even years, to monitor changes in annular gas over the life of the oil and gas field as the reservoir matures and optionally as additional wells are brought into service. Compared to conventional exhaust gas monitoring systems that require manual retrieval of exhaust gas samples and transmission to an onshore laboratory for analysis, certain embodiments of the present invention employ an in-situ method, thereby enabling real-time and efficient analysis.

[0068] Some embodiments of the present invention utilize nondispersive infrared (NDIR) spectroscopy and / or electrochemical methods to analyze the composition of permeate gas escaping from the end fittings of a flexible pipeline. The pipeline may be a single flexible tube that can be arranged as a riser, or it may be formed by multiple flexible tubes arranged end-to-end.

[0069] Some embodiments of the invention utilize an alarm-based system, whereby an alarm is set on a real-time exhaust gas monitoring unit, and a command is generated to open a valve and initiate the injection of one or more injectable gases from a variety of options when the measured level of one or more gaseous substances reaches or exceeds a predetermined threshold. Optionally, the valve is closed and the injection is terminated when the level of a target molecule (such as hydrogen sulfide) drops below the alarm level.

[0070] Certain embodiments of the invention are applicable regardless of whether the annulus is submerged in condensate (yet still sealed) or if the tube is submerged in seawater in the event of damage to the outer sheath. Some of the injected gas dissolves in such water, but the remainder of the injected gas can escape through the permeable water in the recess and enter the gas monitoring system.

[0071] Some embodiments of the invention provide an initial dose / injection of chemicals when an alarm level is reached on one or more annular fluid gaseous substances, thereby allowing the system to monitor and intermittently replenish the dose thereafter. Alternatively, a single initial intervention may be used.

[0072] Some embodiments of the present invention provide “maintenance-free” riser health monitoring, wherein gas is detected and a counteracting fluid can be continuously or repeatedly injected at periodic or non-periodic times.

[0073] Some embodiments of the present invention are applicable to single-length risers.

[0074] Some embodiments of the invention provide the installation of one or more tubes or other fluid communication channels along the entire length or a portion of the length of a flexible tube. Optionally, the tube is added in a spiral pattern following a stretched armor layer. Optionally, the tube has holes along its length until it reaches an end fitting. The tube end connects to an end fitting end face, which provides the opportunity to inject passivating / inhibiting chemicals or purging chemicals into the flexible tube annulus whenever needed. This facilitates the delivery of multiple chemical types depending on the specific problem faced. The pumping system can help control gas composition by using an inert gas to dilute the annulus gas, or, in the presence of sheathing damage and the discovery of liquid ingress, inject chemicals to control the corrosion rate through the passivation of the metal or the removal (purging) of dissolved oxidizing gases.

[0075] Some embodiments of the present invention provide a method for injecting chemicals by mounting one or more tubes (optionally having holes along their length) into a flexible tube annulus, whereby the injection can be controlled at any time depending on the problem, by passivating the metal or removing dissolved oxidizing gases or by neutralizing the annulus fluid or by purging and / or drying the flexible tube annulus.

[0076] Some embodiments of the present invention enable the variation of the concentration level of at least one harmful target fluid, thereby modifying the composition of the annular fluid in the annular region.

[0077] Some embodiments of the invention will now be described below by way of example only, with reference to the accompanying drawings, in which:

[0078] Figure 1 The flexible tube body is shown;

[0079] Figure 2 The application environments and uses of flexible tubes are illustrated;

[0080] Figure 3 An example of a cross-section passing through the body of the flexible tube is shown;

[0081] Figure 4 An example of the void space in the annular region;

[0082] Figure 5 The introduction of fluid into the annulus is illustrated schematically;

[0083] Figure 6 This illustrates how a chemical intervention can be provided to a pipe area by monitoring at least one fluid parameter, and then the chemical intervention can be further controlled and adjusted over time;

[0084] Figure 7 This illustrates how two concentration thresholds can be set, whereby these two thresholds together act as two triggering factors for chemical intervention and / or as tolerance limits for the acceptable concentration range when the fluid parameter in the monitoring data exceeds one or both thresholds; and

[0085] Figure 8 The wet chemical monitoring of fluid concentration in the emptied annular fluid is illustrated.

[0086] In the accompanying drawings, similar reference numerals refer to similar parts.

[0087] Throughout this specification, reference will be made to flexible tubes. It should be understood that certain embodiments of the invention are applicable to a variety of flexible tubes. For example, certain embodiments of the invention can be used for flexible tube bodies and associated end fittings of the type manufactured according to API 17J. Such flexible tubes are generally referred to as unbonded flexible tubes. Other embodiments are associated with other types of flexible tubes.

[0088] It should be understood that the illustrated flexible tube is an assembly of a flexible tube body and one or more end fittings, with the respective ends of the tube body terminated in each of the one or more end fittings. Figure 1 This illustrates how the tube body 100 is formed from a combination of layered materials that form a pressure-bearing conduit. Although Figure 1Several specific layers are shown, but it should be understood that certain embodiments of the invention are broadly applicable to coaxial tube body structures comprising two or more layers made of a variety of possible materials. The tube body may 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 of two or more different materials, such as a material formed of a matrix material and reinforcing fibers.

[0089] Therefore, 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 multiple components, one or more of which are formed from a composite material. The layers or any elements of the composite layer can be manufactured via extrusion, pultrusion, or deposition processes, or via a winding process in which adjacent coils of a strip, each having its own composite structure, are bonded together. Regardless of the manufacturing technique used, the composite material may optionally comprise a matrix or body of a material having a first characteristic, in which additional elements with different physical properties are embedded. That is, elongated fibers aligned to a certain extent or smaller fibers with random orientation can be placed in the body, or spheres or other regularly or irregularly shaped particles can be embedded in the matrix material, or a combination of more than one of the above. Suitablely, the matrix material is a thermoplastic material, which is polyethylene or polypropylene or nylon or PVC or PVDF or PFA or PEEK or PTFE or such material with reinforcing fibers made of one or more of glass, ceramics, basalt, carbon, carbon nanotubes, polyester, nylon, aramid, steel, nickel alloy, titanium alloy, aluminum alloy, etc., or with fillers made of glass, ceramics, carbon, metal, buckyballs, metal silicates, carbides, carbonates, oxides, etc.

[0090] Figure 1 The illustrated tube body 100 includes an internal pressure sheath 110, which serves as a fluid retention layer and includes a polymer layer ensuring 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 include multiple sublayers. It should be understood that when using the carcass layer 120, 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 operation), the internal pressure sheath may be referred to as a liner. Figure 1 An example is a barrier layer 110 on the radially outer side of the carcass layer 120.

[0091] It should be noted that the carcass layer 120 is a pressure-resistant layer providing an interlocking structure that can be used as the innermost layer to completely or partially prevent the inner pressure jacket 110 from collapsing due to tube decompression, external pressure, tensile armor pressure, and mechanical fracture loads. The carcass is a pressure-resistant layer. It should be understood that certain embodiments of the invention are therefore suitable for 'coarse-hole' applications (with a carcass). Suitably, the carcass layer is a metallic layer. Suitably, the carcass layer is formed of stainless steel, corrosion-resistant nickel alloys, etc. Suitably, the carcass layer is formed of composite materials, polymers, or other materials or combinations of materials and components. The carcass layer is typically radially positioned within the barrier layer.

[0092] A carcass layer is a "layer" in the sense that it is formed in a single channel at a single manufacturing node on the innermost and outermost radial surfaces. A single manufacturing node may comprise multiple strip processing segments that are axially close together such that these segments effectively constitute 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.

[0093] The tube body includes a pressure armor layer 130, which is a pressure-resistant layer providing structural support and increasing the flexibility of the tube against internal and external pressures, as well as mechanical fracture loads. This layer also structurally supports the internal pressure sheath. Appropriately, such as Figure 1 As shown, the pressure armor layer is formed as a tubular layer. Suitably, for unbonded flexible tubes, the pressure armor layer consists of an interlocking structure of lines with an arrangement angle close to 90°. Suitably, in this case, the pressure armor layer is a metallic layer. Suitably, the pressure armor layer is made of carbon steel, aluminum alloy, stainless steel, etc. Suitably, the pressure armor layer is formed from a pultruded composite interlocking layer. Suitably, the pressure armor layer is formed from a composite material formed by extrusion, pultrusion molding, or deposition. The pressure armor layer is positioned radially outward of the illustrated lower barrier layer.

[0094] The illustrated flexible tube body also includes a first tensile armor layer 140 and a second tensile armor layer 150. Each tensile armor layer is used to maintain tensile loads and optionally also maintain internal pressure. Suitably, for some flexible tubes, the tensile armor coil is metallic (e.g., steel, stainless steel, or titanium). For some composite flexible tubes, the tensile armor coil may be a polymer composite strip coil (e.g., provided with thermoplastic, such as nylon, matrix composite, or thermosetting, such as epoxy resin, matrix composite). For non-bonded flexible tubes, the tensile armor layer is formed of multiple wires (to impart strength to the layer), which are positioned above the inner layer and helically wound along the length of the tube at an angle typically between about 10° and 55°. Suitably, the tensile armor layers are wound in pairs in opposite directions. Suitably, the tensile armor layer is a metallic layer. Suitably, the tensile armor layer is formed of carbon steel, stainless steel, titanium alloy, aluminum alloy, etc. Suitably, the tensile armor layer has a microstructure composed of oriented sheets. Appropriately, the tensile armor layer is formed from composite materials, polymers, or other materials or combinations thereof.

[0095] Suitable, the flexible tube body includes an optional strip layer 160, which helps to contain the underlying layers and, to some extent, prevents abrasion between adjacent layers. The strip layer may optionally be a polymer or composite material or a combination of materials, and may also optionally include a tubular composite layer. The strip layer can help prevent metal-to-metal contact, thus aiding in preventing abrasion. The strip layer on the stretch armor can also help prevent “strand separation” of the stretch armor wires.

[0096] The flexible tube body also includes an optional inner insulation layer 165 and an outer sheath 170, which comprises a polymer layer for protecting the tube from penetration, corrosion, abrasion, and mechanical damage from seawater and other external environments. Any insulation layer helps limit heat loss through the tube wall to the surrounding environment. The annular space 180 is the area associated with the space between the inner pressure sheath 110 and the outer sheath 170. In other words, in Figure 1 In the illustrated flexible tube body, the pressure armor layer 130, the first tensile armor layer 140, the second tensile armor layer 150, the strip layer 160, and the insulation layer 165 are located within the annular region 180. It should be understood that in some embodiments, the annular region 180 may include elements present in… Figure 1 The flexible tube body shown may contain any or no layers. The elements between opposing fluid-retaining layers act as spacers, and the void space is located between those elements in the annular region.

[0097] The flexible tube includes at least a portion (referred to as a segment or section) of a flexible tube body 100 and an end fitting located at at least one end of the flexible tube. The respective end fitting is available for terminating each end of the flexible tube body. The end fitting provides mechanical means for forming a transition between the flexible tube body and the connector. For example, as... Figure 1 The different tube layers shown are terminated in the end fittings to transfer loads between the flexible tube and the connector.

[0098] Figure 1 One or more conduits 190 are also illustrated, which are wound instead of tension armored windings to provide a fluid communication channel extending along a flexible tube body. It should be understood that such conduits (described in more detail below) may optionally extend along the entire length of the flexible tube body connected to two respective end fittings, or may extend only from one selected end fitting and terminate at an open or sealed end at a desired length along the flexible tube body. In the case of a conduit with a sealed end, one or more openings in the conduit wall can be utilized, as described in more detail below. Such conduits may have similar or different lengths. It should also be understood that, although... Figure 1 The illustrated fluid communication channel 190 is shown as the outermost tension armored winding, but the fluid communication channel may additionally or alternatively be provided by the innermost tension armored winding, or actually provided by winding in another winding layer and / or a combination of these options. Furthermore, the fluid communication channel may not be helically wound, but may optionally be formed by a pressure-resistant tube disposed between opposing layers within the flexible tube body. This tube may be “straight” or may be wound in a manner that does not necessarily involve a helix with repeating pitch.

[0099] The pressure-resistant body of the tube defines an inner cavity along which fluid can flow. This effectively provides a fluid communication channel, a way in which fluid can be transferred from one location to another, thereby connecting two locations and enabling fluid communication between those connected locations.

[0100] Figure 2 An example is illustrated of a riser assembly 200 suitable for transporting produced fluids such as oil and / or natural gas and / or water from a seabed location 210 to a floating facility 220. For example, in... Figure 2 In the middle, seabed location 210 includes a flexible floating pipeline 225. The flexible floating pipeline 225 includes a flexible pipe wholly or partially resting on or buried beneath the seabed 230 for static applications. Floating facilities may consist of platforms and / or buoys or, as... Figure 2 The vessel shown is provided with a riser assembly 200, which is configured as a flexible riser, that is, a flexible pipe 240 connecting the vessel to the seabed facility. Alternatively, the flexible pipe may be part of a section of the pipeline that includes a flexible pipe body with connecting end fittings.

[0101] It should be understood that different types of risers exist, as is well known to those skilled in the art. Certain embodiments of the present invention can be used with any type of riser, such as freely suspended risers (free-suspension catenary risers), partially constrained risers (buoys, chains), fully constrained risers, or risers enclosed in tubes (I-tubes or J-tubes). Some (but not all) examples of such configurations can be found in API 17J. Figure 2 It also shows how a portion of the flexible tube can be used as a jumper wire 250.

[0102] Figure 3 Helpful examples demonstrate how to pass through Figure 1 The illustrated cross-section or view of the flexible tube body helps illustrate how the outer surface 300 of the inner pressure sheath 110 is substantially coaxial with and spaced apart from the inner surface 310 of the outer sheath 170. The outer surface 300 of the inner pressure sheath and the inner surface 310 of the outer sheath are spaced apart and substantially coaxial, thus defining an annulus 180. This annulus is a region within the flexible tube body. The annulus extends along the entire length of the flexible tube. The annulus region 180 is an annular-shaped region. It should be understood that certain embodiments of the invention are applicable to flexible tube bodies comprising one or more intermediate fluid retention layers. When such intermediate fluid retention layers are used in a flexible tube body, multiple annulus are defined. Each annulus is an annular-shaped region between a fluid-dense radially outer inner layer and a radially inner surface of the outer fluid retention layer.

[0103] Figure 3 It also helps to illustrate how the wires in the inner stretch armor layer 140 and the outer stretch armor layer 150 are extended to form a metal layer. Figure 3 This illustrates how each of the three wires in the outer stretch armor layer 150 can be replaced by a corresponding tube 190 to provide a corresponding fluid communication channel along the length of the flexible tube body. Suitably, each fluid communication channel 190 is a conduit, for example, provided by a rated pressure tube. This conduit has sufficient compressive strength to prevent it from being deformed during manufacturing and to prevent it from breaking during the service life of the flexible tube. Suitably, the conduit is a steel tube or other metal tube, a corrosion-resistant alloy tube, or an extrusion-resistant polymer composite tube. Suitably, the conduit is formed from a malleable material so that it can be wound. Suitably, the conduit is a copper tube. Suitably, the conduit is a rated pressure steel tube. Suitably, the conduit has a rated pressure.

[0104] like Figure 3As illustrated, three conduits may be provided along the length of the flexible tube. It should be understood that, alternatively, one, two, three, four, or more conduits may be provided. These conduits may optionally be evenly distributed around the circumference of the tube, or may be arranged more closely at desired locations on the circumference. It should also be understood that such fluid communication channels may be provided within a mixture layer, such as one or more conduits in an outer tensile armor layer and one or more conduits in an inner tensile armor layer. As an alternative, such as... Figure 3 As illustrated, all conduits functioning in fluid communication can be positioned within a common layer. These conduits are in fluid communication with the annular region of the flexible tube in which they reside.

[0105] Figure 4 The help provides an illustrative example of how to achieve this. Figure 3 An enlarged view of a portion of the cross-section of the illustrated flexible tube body. The carcass layer 120 is provided by interlocking windings. The barrier layer 110 has a radially innermost surface 400 that defines the inner bore of the flexible tube body during use. The radially outermost surface 300 of the barrier layer is also... Figure 4 As illustrated in the example. The radial outermost surface 410 of the outer sheath 170 is also... Figure 4 As illustrated, the same applies to the radial innermost surface 310 of the outer sheath 170.

[0106] Figure 4 This illustrates how annulus 180, defined by the spaced-apart inner surface 310 of the outer sheath and the outer surface 300 of the barrier layer, partially fills other components of the flexible tube. However, a void space 450 is defined within the annulus. The void space 450 is the volume of the annulus region that remains empty and is not filled with material supplied by other elements / components of the flexible tube body. Figure 4 This illustrates how the components of the produced fluid traveling downwards along the orifice will tend to permeate through the barrier layer 110 in the direction indicated by arrow A during use, and may otherwise accumulate in the void spaces 450 within the annulus 320 of the flexible tube. As previously mentioned, such accumulation of permeated fluid, if permitted, can prove detrimental to the service life of the flexible tube body.

[0107] Figure 5 A system 500 is illustrated for the composition of annular fluid in at least one annular region of a modified flexible tube. Figure 5 A segment of the flexible tube body 100 is illustrated. An end fitting 505 terminates at an end region 506 of the flexible tube body 100, which extends toward another end (not shown), where it terminates at another end fitting (not shown). Figure 5 As illustrated, the flexible tube body includes a fluid-connecting conduit 190. This fluid-connecting conduit is wound within the flexible tube body like a stretched armor line. This is in Figure 5The illustration is schematic. It should be understood that the conduit forming part of the tensile armor line will be located within the annular region of the flexible tube body.

[0108] Figure 5 The illustration also illustrates how the conduit 190 includes an orifice 510 in the lower region 515. That is, the conduit 190, which may be supplied by a rated pressure steel pipe or the like, has no orifice along its upper length near the upper end fitting 506, but includes an orifice in another region. It should be understood that, as an alternative, orifices may be provided along the entire length of the conduit 190 or in different regions thereof.

[0109] For example, Figure 5 This illustrates a scenario where the outer sheath is damaged. This allows surrounding seawater to intrude into the 180° annulus, and Figure 5 The upper limit of the inlet region 520, illustrated by the upper surface of the submerged seawater 525, is shown. It should be understood that certain embodiments of the invention can be used to monitor problems other than damage to the outer sheath and therefore, inlet to one or more annulus spaces in the flexible tube. Figure 5 An example of a flexible tube in a slightly vertical orientation is illustrated. It should be understood that certain embodiments of the invention are applicable to flexible tubes arranged in other configurations, such as horizontal or inclined relative to the seabed, or having one or more bends.

[0110] Figure 5 The illustrated system 500 includes a first injection pump 530 and another injection pump 535. Each of these injection pumps is a positive pressure pump. That is, when powered on, the pump can inject the corresponding fluid from the corresponding source into the corresponding inlet of the end fitting 505, and into the annulus 180 via the corresponding fluid connection channel through the end fitting.

[0111] Figure 5 The illustrated first positive pressure pump 530 is in fluid communication with a nitrogen source 540, which is provided by a container containing nitrogen gas. Figure 5 Another illustrated positive pressure pump 535 is fluidly connected to two different fluid sources: one is a source of corrosion inhibitors (e.g., chemicals from the Corrtreat brand of Clariant Oil Services), and the other is a fluid containing a hydrogen sulfide scavenger. This fluid can be water, oil, or grease. For example, it can be an oxygen scavenger or a biocide.

[0112] It should be understood that corrosion inhibitors may include 2-butoxyethanol and / or 2-mercaptoethanol and / or ethylene glycol and / or 2-aminoethanol, etc. Appropriately, corrosion inhibitors may not include 2-butoxyethanol and / or 2-mercaptoethanol and / or ethylene glycol and / or 2-aminoethanol.

[0113] Figure 5It also illustrates how each corresponding pump receives a control signal to energize and start the pump, thereby selectively injecting the corresponding fluid into the annulus of the flexible tube body, thus modifying the composition of the annular fluid in at least one annular region of the flexible tube. Figure 5 The system includes a Real-Time Exhaust Gas Monitoring (RTVGM) system to provide control signals to each corresponding positive pressure pump. The RTVGM system 540 monitors the concentration of gaseous substances in the annulus. This may include monitoring gaseous substances, including those that may cause stress corrosion cracking. Monitoring can be performed once, periodically, or continuously to allow monitoring of the evolution of gaseous substances in the flexible tube annulus over a given time period or throughout its service life. The RTVGM 540 provides continuous and / or scheduled and / or intermittent real-time data so that gases can be analyzed in situ. Optionally, the RTVGM 540 measures the flow rate and pressure in the annulus, as well as the concentration of gases such as carbon dioxide, methane, hydrogen sulfide, and oxygen. Chemical analysis can be performed on the permeated annulus gases in real time.

[0114] The RTVGM 540 includes an analyzer 545 that queries data and provides trend and / or threshold analysis. In this way, appropriate alarm commands can be generated in real-time and in-situ and provided to the positive pressure pumps 530, 535. For example, when the RTVGM determines that the H2S level has reached a predetermined level, an alarm signal is generated and provided to another positive pressure pump 535. This initiates the pumping of a fluid containing an H2S scavenger, thus injecting that fluid into the annular space to aid in the modification of the component and thereby regulate the H2S level.

[0115] Figure 5The diagram also illustrates how a real-time sheath breakage detection system 550 can be included. This provides real-time information. The sheath breakage detection system 550 can determine the time and location of annular sheath breakage. Appropriately, the sheath breakage detection system can determine the location of annular water. Appropriately, the real-time sheath breakage detection system can detect annular fluid ingress. Optionally, the sheath breakage detection system can utilize an electrically isolated existing load-bearing tension line (not shown) to help determine in real-time when the outer sheath of the flexible tube body has broken. When an outer sheath breakage is detected, a corresponding command signal can be provided to another positive pressure pump 535. This can be used to inject corresponding counteracting fluid from a local fluid source into the annular space. It should be understood that other types of breakage detection systems can alternatively or may be integrated or connected to system 500 to assess annular conditions on a continuous, planned, or intermittent basis. Examples of such damage detection systems are: Distributed Temperature Sensing (DTS) systems that can detect small localized temperature changes around a break in the outer sheath of a flexible pipe body when freshwater flows into or exchanges with water from the annulus; Distributed Acoustic Systems (DAS) that combine one or more acoustic emitters and / or sensors; Ultrasonic Testing (UT) inspection systems; and Motion-Displacement / Accelerometer / Bending Frequency Monitoring systems that can detect changes in the way the pipe moves or provide information that can infer changes in friction between pipe body layers or damage to the riser structure.

[0116] Figure 5 An example is illustrated of how system 500 may also include a negative pressure pump 570. This can be used to selectively drain fluid from the annulus via appropriate vent paths and vents in the end fittings. This can be achieved via an injection conduit (effectively reversing the injection concept) or via one or more “dedicated” drain conduits. This helps enable system 500 to perform wet chemical experiments on the drained fluid and determine the pH or concentration of previously injected intervention chemicals in the drained fluid, allowing the system to stop, moderate, or increase further chemical injections to bring the chemical properties of the annulus fluid into a desired or acceptable range.

[0117] Figure 5 It also illustrates how system 500 may include a gas purging exhaust device 580. This gas purging exhaust device can help treat exhaust gases from the annulus by chemical neutralization and capture or by directing the gases to burn in a flare system on the floating facility 220.

[0118] Figure 6 The illustration shows how a tube can be introduced through an orifice along at least one region of a conduit that passes through the body of a flexible tube. Figure 6 Arrow 590 illustrates a fluid flow that modifies the composition of the annular fluid. For example, passivation of metal surfaces can be achieved by injecting phosphate-related chemicals.

[0119] System 500 analyzes the environment and determines when certain changes have occurred. This helps induce the pump to inject the appropriate chemicals and / or gases to bring the overall environmental conditions "under control." An analytical unit, injection kit, and one or more injector tubes can be utilized during the manufacture of the flexible tube body, and these can optionally follow a helix in a stretch-armored line. The conduit, or each conduit, has one or more orifices along its length and / or at its open end. The system provides the ability to inject passivating and / or inhibiting chemicals and / or purging chemicals and / or chemically inert purge fluids into the annulus whenever passivating chemicals and / or inhibiting chemicals and / or purging fluids are needed. This can be achieved without human operator assistance.

[0120] Figure 6 The example illustrates how System 500 can acquire data from monitoring at least one fluid parameter (temperature, concentration, etc.) and provide chemical intervention, which can then be further controlled and adjusted over time. It should be understood that... Figure 6 An example of how system 500 can respond to fluid parameters is shown. Acidic gaseous substance 620 (such as...) Figure 6 The pressure or concentration 610 of H2S (as shown) can be monitored at the end fitting vent and at a set of trigger values ​​(programmed into the system), where intervention can be triggered automatically by the system 500 or via another monitoring system that can communicate with the system 500. It should be understood that... Figure 6 Example data 630 is provided, showing a concentration 610 (in parts per million, ppm) of H2S 620 monitored relative to time 640 (i.e., the time for which the fluid parameter was monitored). It should be understood that... Figure 6 The times shown can be in units such as years, months, days, hours, minutes, or seconds. For example... Figure 6 As illustrated in the fluid monitoring example, a trigger level 650 (which can be a predetermined trigger level and / or a user-defined or user-programmed trigger level, etc.) of approximately 35 ppm of H2S detected (which may be approximately 40 ppm, or between 35 ppm and 40 ppm, or approximately 35 ppm, 36 ppm, 37 ppm, 38 ppm, 39 ppm, or 40 ppm) triggers the injection of a predetermined volume of H2S scavenger and / or nitrogen purging. That is, a measured concentration of H2S in the annulus at or above the trigger level causes the system 500 to inject H2S scavenger and / or purge with nitrogen. It should be understood that the injection volume of the H2S scavenger can be calculated based on the known empty volume within the annulus of the flexible tube body not occupied by the armor or strip.

[0121] like Figure 7As shown, shortly after the initial chemical injection, ongoing H2S monitoring detected a subsequent decrease in the H2S concentration of 630 in the loop void region, and the H2S concentration further decreased below the injection trigger level of 660. It should be understood that, as Figure 7 As shown, after a period of time, the beneficial effects of the chemical injection have been offset by further penetration of H2S 620, and as the H2S concentration increases again to 630 and reaches the trigger value of 650, another chemical intervention is triggered. This sequence can continue until the flexible tube is considered to have reached the end of its service life.

[0122] Therefore, it should be understood how System 500 can provide automatic control over abnormal fluid conditions in the annular void region.

[0123] Figure 7 This illustrates how two concentration thresholds, 710 and 720, can be set together to act as two triggers for chemical intervention and / or as tolerance limits for the acceptable concentration range. Figure 7 In the example shown, the acceptable concentration is related to the hydrogen concentration in the annular exhaust gas. It should be understood that the hydrogen concentration in the annular exhaust gas is an example of a fluid parameter. It should also be understood that... Figure 8 An example is shown: a graph of hydrogen concentration in the annular exhaust gas versus time (where the hydrogen concentration in the annular exhaust gas is measured) 725. For example... Figure 8 As shown, after the hydrogen concentration in the annular exhaust gas increases above / exceeds the lower initial control trigger level 710 (730), system 500 provides an injection of a corrosion inhibitor to reduce corrosion (in this case, its triggering produces hydrogen as a byproduct of corrosive activity). Following the injection of the corrosion inhibitor, the hydrogen concentration continues to rise (730), albeit at a slower rate than before the injection, and a second intervention chemical injection is triggered when the detected concentration crosses the higher second control trigger level 720 (740). It should be understood that this second injection is provided by system 500. The hydrogen concentration in the annular exhaust gas then decreases over time (750), and further intervention is triggered only if it rises again above one or both concentration thresholds (710, 720).

[0124] Figure 8 Examples of wet chemical monitoring of fluid concentrations are illustrated, in which Figure 8 The concentration 810 shown is the concentration of a phosphate-based inhibitor monitored continuously or intermittently in the emptied annular fluid. That is, concentration 810 is an inhibitor concentration, optionally a phosphate-based inhibitor. Appropriately, any other suitable inhibitor or fluid may be used. It should be understood that... Figure 8 An example is shown: a graph illustrating the concentration of phosphate-based inhibitors in the emptied annulus as a function of time (i.e., the time during which the emptied annulus was monitored). Chemical intervention (by...)Figure 8 The system 500 in the inspector is provided in the form of a phosphate inhibitor, which has been detected due to the presence of water in the annulus of the flexible tube body. ​ The process continues (as shown in the graph, previously triggered) until the inhibitor concentration in the emptied annular fluid exceeds the first / initial control trigger level 820 and reaches (or exceeds) a higher second control trigger level 830, at which point the injection (of the phosphate-based inhibitor by system 500) is stopped. Following injection, the inhibitor concentration gradually decreases over time 840, and as it approaches the lower initial control trigger level 820, further chemical intervention is initiated (provided by system 500) in the form of additional inhibitor to prevent the inhibitor concentration from falling below the lower limit / quantity of the desired inhibitor concentration range in the emptied annular fluid. Appropriately, further chemical intervention may be initiated when the inhibitor concentration falls below the lower (initial) control trigger level. ​ As shown, the inhibitor concentration in the emptied annular fluid begins to rise again at 850 until it approaches the higher second control trigger level 830 again. At this point, the system adjusts further chemical intervention as needed to maintain the inhibitor concentration in the emptied annular fluid between an acceptable upper and lower limit defined by the second control trigger level 830 and the initial control trigger level 820.

[0125] It should be understood that the chemical deployment chamber (in which the system 500 can supply chemicals such as phosphate inhibitors to the tubular area) can also be used as a sampling device to extract liquid from the annulus and perform wet chemical analysis to establish, for example, pH and / or phosphate concentration and / or determine whether they are within the expected range and / or determine future chemical deployment parameters, etc.

[0126] Throughout the detailed description and claims, the terms "comprising" and "containing," and variations thereof, mean "including but not limited to," and are not intended to (and do not) exclude other parts, additives, components, integrals, or steps. Throughout the detailed description and claims, the singular encompasses the plural unless the context requires otherwise. Specifically, where indefinite articles are used, the description should be understood to consider both the plural and the singular unless the context requires otherwise.

[0127] Features, integrals, characteristics, or groups described in connection with a particular aspect, embodiment, or example of the invention should 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 appended claims, the abstract, and the 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 of the foregoing embodiments. The invention extends to any novel feature or novel combination of features disclosed in this specification (including any appended claims, the abstract, and the drawings), or to any novel step or novel combination of steps of any method or process so disclosed.

[0128] The reader’s attention is drawn to all papers and documents filed concurrently with or prior to this specification in conjunction with this patent application that disclose a public examination of this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

1. A method for determining the composition of annular fluid in at least one annular region of a modified flexible tube, the method comprising the following steps: Provide at least one alarm signal indicating that a predetermined condition associated with an annular region in the flexible tube body of the flexible tube is met; In response to each alarm signal, at least one pump element is actuated, the at least one pump element being selectively in fluid communication with a plurality of containers each containing a corresponding source of a corresponding counteracting fluid, the corresponding counteracting fluid being a fluid that counteracts a corresponding predetermined fluid condition; as well as At least one counteracting fluid is provided to the annular region, thereby modifying the composition of the annular fluid in the annular region.

2. The method according to claim 1, further comprising: Determine the corresponding concentration levels of various target fluids in the corresponding annular region within the flexible tube body; Determine at least one specific concentration level that satisfies a predetermined condition, which indicates that the corresponding target fluid is a harmful target fluid; as well as By altering the concentration level of at least one harmful target fluid, the composition of the annular fluid in the annular region is modified.

3. The method according to claim 2, wherein the method further comprises: Determining the appropriate concentration level includes determining whether the target fluid is present in a sample of annular fluid from the annular region.

4. The method according to claim 3, wherein the method further comprises: If a target fluid is identified, the total percentage of the target fluid in the annular fluid is determined for each harmful target fluid.

5. The method according to claim 2 and any one of its dependent claims, wherein the method further comprises: The corresponding concentration level is determined via an analyzer module that is in fluid communication with a fluid communication channel and is configured to sample and identify multiple component target fluids in the annular fluid.

6. The method according to any one of the preceding claims, the method further comprising: The composition is modified by altering the concentration level of each of the at least one harmful target fluids by selecting at least one injectable counteracting fluid from a variety of possible injectable counteracting fluids and injecting the selected injectable counteracting fluid into at least one fluid communication channel, wherein the at least one fluid communication channel extends along a portion of the annular region and is in fluid communication with at least one region in the annular region.

7. The method according to claim 2, further comprising: For each harmful target fluid, select at least one injectable counteracting fluid; as well as The injectable counteracting fluid from the corresponding counteracting fluid source is provided into the annular region.

8. The method according to any one of the preceding claims, the method further comprising: Fluid is propelled at positive pressure through the pump element into the annular region via the inner cavity, which is spirally disposed in the annular region and provides a fluid communication channel along the annular region.

9. The method according to claim 2 and any one of its dependent claims, wherein the method further comprises: By simultaneously and repeatedly determining that the measurement level of each of the multiple harmful target fluids is equal to or greater than a preset threshold, at least one concentration level is determined to satisfy a predetermined condition.

10. The method according to any one of the preceding claims, the method further comprising: Each counteracting fluid is provided by injecting a portion of the passivating fluid and / or inhibiting fluid and / or scavenging fluid into the annular region.

11. The method according to any one of the preceding claims, the method further comprising: A negative pressure is applied to the annular region via a pump element, thereby selectively extracting the annular fluid from the annular region.

12. The method according to any one of the preceding claims, the method further comprising: Actuating at least one pump element includes actuating a single pump element or actuating multiple pump elements, the single pump element being selectively in fluid communication with multiple containers, each of the multiple pump elements being selectively in fluid communication with at least one container ...

13. The method according to claim 12, wherein the method further comprises: The step of actuating the plurality of pump elements includes simultaneously or sequentially actuating the pump elements among the plurality of pump elements, thereby simultaneously or sequentially injecting the corresponding counteracting fluid into the annular region.

14. An apparatus for determining the composition of annular fluid in at least one annular region of a modified flexible tube, the apparatus comprising: At least one positive pressure pump element, the at least one positive pressure pump element being selectively in fluid communication with a plurality of respective counteracting fluid containers for storing respective counteracting fluids; At least one alarm generator unit, each alarm generator unit being used to provide at least one corresponding alarm signal, the at least one alarm signal indicating that a predetermined condition associated with an annular region in the flexible tube body of the flexible tube is satisfied; in The positive pressure pump element can be actuated to selectively inject one or more fluids from the offset fluid container into the annular region, thereby modifying the composition of the annular fluid in the annular region.

15. The apparatus of claim 14, further comprising: The alarm generator unit is an acoustic and / or electromagnetic monitor, or a distributed temperature sensing (DTS) sensor, or a distributed acoustic sensing (DAS) sensor, or a real-time sheath damage detection system.

16. The apparatus according to claim 14 or claim 15, wherein the apparatus further comprises: The at least one positive pressure pump element comprises a single positive pressure pump element that is selectively in fluid communication with a plurality of containers of a corresponding counteracting fluid, or the at least one positive pressure pump comprises a plurality of pump elements, each pump element being selectively in fluid communication with at least one container of a corresponding counteracting fluid.

17. The apparatus according to any one of claims 14 to 16, the apparatus further comprising: The at least one alarm generator includes a real-time exhaust gas monitoring system, which provides output data indicating the corresponding concentration level of at least one annular fluid substance and generates a corresponding alarm command when the concentration level is equal to or exceeds a corresponding predetermined threshold.

18. The apparatus of claim 17, further comprising: The at least one alarm generator further includes a real-time sheath damage detection system.

19. A flexible tube, the flexible tube comprising: A flexible tube body, the flexible tube body including an inner fluid retention layer and another fluid retention layer, the other fluid retention layer being radially outside the inner fluid retention layer and spaced apart from the first fluid retention layer to provide an annular region therebetween; At least one conduit extending from a fluid inlet end of the flexible tube body along at least a portion of the entire length of the flexible tube body, the at least one conduit including at least one opening, each opening being disposed at a corresponding location along the length of the conduit for delivering counteracting fluid injected at the fluid injection end of the conduit into the void space in the annular region; and An end fitting is provided, which terminates at the fluid inlet of the flexible tube body, and includes at least one fluid injection port that can be connected to the outlet of at least one positive pressure pump element.

20. The flexible tube according to claim 19, wherein the flexible tube further comprises: The end fitting further includes at least one fluid vent port, which is connectable to a negative pressure pump element for selectively venting fluid partially or completely from the annular region; and The end fitting further includes a gas exhaust port.

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