FLUID INTAKE SYSTEM

Abstract

A fluid intake system is disclosed for use with a flow control device which controls fluid flow into a tubular. The fluid intake system comprises a manifold configured to circumscribe a tubular which includes a flow control device, the manifold comprising a plurality of circumferentially arranged inlet ports for receiving a fluid into the manifold. The system includes a fluid outlet to be arranged in communication with the flow control device to, in use, communicate fluid from the manifold to the flow control device.

Description

FIELD

The present disclosure relates to a fluid intake system such as for use with or as part of downhole flow control systems, and uses thereof.

BACKGROUND

Wellbore completions often include inflow control devices which assist with controlling the amount and/or type of fluid that is allowed to pass from a reservoir into a production flow path. A subterranean hydrocarbon reservoir typically produces both hydrocarbons (such as oil and natural gas) and water, with it being only the production of hydrocarbons that is desired. Further, it may also be the case that production of specifically only one kind of hydrocarbon, such as oil, is desired. In this instance, it may be desirable to implement a control system that optimises oil production from the reservoir, while limiting the production of water and natural gas. The concept of selectively producing fluids from a subterranean hydrocarbons reservoir is well known in the art, with the principles being utilised to optimise production of the desired fluid from the reservoir.

When producing fluid from a reservoir, it is not always desirable to have a flow control device that switches instantaneously between a fully open to a fully closed position when an undesired fluid (or a desired fluid containing elements of an undesired fluid) begins to be produced, due to loss of sinkhole (or pressure drawdown) around the wellbore and possible loss or reduced production of desired wellbore fluid. Further, it is not desirable to have a device that switches from a fully closed position to a fully open position when the desired fluid begins to be produced, as rapid onset of an undesired fluid may occur.

An additional complicating factor occurs in highly deviated/horizontal wellbores, wherein the fluid phases of the reservoir fluid separate due to their differing densities (e.g. water, oil and gas separate into different fluid ‘layers’ in a highly deviated/horizontal wellbore, given their differing densities), as shown in FIGS. 1A and 1B. When only a single point of inflow of reservoir fluid is provided within a production tubular (disposed in a highly deviated/horizontal wellbore), the single point of inflow may only be exposed to a single (separated) ‘layer’ of wellbore fluid. If an autonomous inflow control device is used at the single point of inflow, said device will only be exposed to the fluid ‘layer’ within which it is disposed (again, as shown within FIGS. 1A and 1B). This means that production of hydrocarbons may be curtailed if the point of inflow within the production tubular is exposed to an undesired fluid, thereby autonomously ceasing production through said point of inflow; potentially leaving recoverable hydrocarbons in the wellbore.

SUMMARY

An aspect of the present disclosure relates to a fluid intake system for use with a flow control device which controls fluid flow into a tubular, the fluid intake system comprising:

• • a manifold configured to circumscribe a tubular which includes a flow control device, the manifold comprising a plurality of circumferentially arranged inlet ports for receiving a fluid into the manifold; and
  • a fluid outlet to be arranged in communication with the flow control device to, in use, communicate fluid from the manifold to the flow control device.

During use, fluid in which the manifold is immersed (e.g., fluid in an annulus surrounding the tubular) is received through each inlet port of the manifold and then communicated to the flow control device via the fluid outlet. The fluid may be defined as a downhole fluid. The fluid may be a reservoir fluid which may contain hydrocarbons. The fluid may be referred to as a produced fluid. When a fluid such as a downhole fluid is collected and/or flowed in a highly deviated or horizontal wellbore, the fluid may undergo stratification; whereby each fluid constituent (e.g. water, oil or natural gas) of the fluid separate form one and other, due to their differing densities. For example, a multiphase fluid formed of water, oil and natural gas may stratify within a highly deviated or horizontal wellbore with the water forming a lower layer, the gas forming an upper layer and the oil forming an intermediate layer.

By having a plurality of circumferentially arranged inlet ports on the manifold, the fluid received into the manifold and thus delivered to the flow control device may provide a better representation of the composition of the fluid (i.e., a better representation of fluid within an annulus surrounding the tubular). For example, in stratified fluids, fluid may be received from each stratified layer, such that a reconstituted fluid may ultimately be delivered to the flow control device. Therefore, the fluid provided at the outlet of the fluid intake system has substantially the same composition as the fluid prior to intake and thus gives an accurate representation of what is being produced from the wellbore, and production rates can be varied accordingly; for example, in accordance with the intended fluid control principles of the flow control device.

By having a fluid intake system that accurately depicts the composition of the original fluid, despite conditions such as stratification, the associated flow control device may be permitted to more accurately provide control, for example autonomous control, over fluid flow into the tubular. An autonomous inflow control device may be reactive to the fluid that is provided at its inlet. For example, an autonomous flow control device may be reactive to the density of a fluid provided at its inlet. An autonomous flow control device may be reactive to the viscosity of a fluid provided at its inlet. An autonomous flow control device may be reactive to the bulk modulus of a fluid provided at its inlet. An autonomous flow control device may be reactive to a combination of characteristics of the fluid provided at its inlet. If said inlet receives a fluid that is an accurate representation of the full composition of the fluid the autonomous flow control device can maintain production at an optimal level, based on the actual constitution of the downhole fluid. This may ensure that the amount of recoverable hydrocarbons produced is maximised, keeping production of downhole fluid as efficient as possible.

In some examples the flow control device may be passive, and may, for example, provide no ability to react to the fluid type flowing therethrough. For example, the flow control device may only function as an inlet into the tubular. In such a case the fluid intake system may provide advantages in terms of allowing the collection of multiple phases of a fluid to ensure that a target phase (e.g., oil or gas) is still produced.

The fluid intake system may alternatively or additionally be defined as a fluid collector system.

The plurality of circumferentially arranged inlet ports may be provided and distributed in a manner to preferentially provide a reconstituted fluid at the outlet which compositionally reflects the original fluid. For example, if the original fluid is formed of 50% water, 30% oil and 20% natural gas, the arrangement of the inlet ports may permit the fluid that is received into the manifold to be substantially 50% water, 30% oil and 20% natural gas.

The inlet ports may be evenly circumferentially distributed on or about the manifold. Evenly spacing the inlet ports in this manner may assist to ensure there is at least one inlet port in each layer of the fluid that has undergone stratification. Furthermore, an even intake of fluid around the tubular may be provided, allowing a more accurate representation of the fluid to be delivered to the flow control device via the fluid outlet. Also, an even distribution of inlet ports may enable a more even intake of fluid around the tubular independent of the orientation of the manifold when deployed. The offset between the inlet ports may be selected by the user based upon the application. In one example, the inlet ports may be spaced with 15° phasing between each. Any suitable phasing may be used between inlet ports that are evenly offset with respect to one and other within the understanding of the skilled person.

The manifold may have any number of inlet ports suitable for sufficient collection of fluid to provide an accurate representation of the composition of the fluid. Furthermore, the manifold may comprise a sufficient number of inlet ports to optimally intake a more accurate representation of the fluid surrounding the tubular, for example which may have undergone a degree of stratification. In some examples, the manifold may comprise any number of inlet ports, such as in the range of 2 to 40. The exact number of ports selected may be based upon the application, the diameter of the inlet ports, and/or the like.

The manifold of the fluid intake system may be formed of a conduit. The conduit may be configured to circumscribe a tubular. The conduit may be configured to fully circumscribe a tubular. The conduit may be configured to partially circumscribe a tubular. The conduit may be provided as a closed loop, with fluid able to flow around the entirety of the loop. The conduit may comprise two end points, wherein fluid may freely flow along the conduit between the end points. It will be appreciated that the term circumscribe is not intended to limit the manifold to be arranged around a tubular in an exactly circular manner, and that the manifold may be arranged around or partially around the tubular in any form that may generally surround a tubular. For example, the manifold may be generally oval, polygonal, etc.

An outlet port may be disposed on the manifold, wherein fluid may exit the manifold via said outlet port. In an example wherein the manifold is formed of a conduit comprising two end points (with fluid flowing along the conduit between the end points), the outlet port may be provided at a mid-point between the end points of the conduit. Such an arrangement may ensure that fluid may only flow in one direction upon entry to the manifold towards the outlet port. This ultimately may provide a more balanced manifold. The manifold may be formed of any suitable material within the understanding of the skilled person.

The fluid intake system may include a filtering arrangement configured to filter fluid prior to and/or during intake into one or more of the inlet ports. The manifold may be provided within an external filter. For example, the manifold may be surrounded by a mesh, or any material suitable for filtering downhole fluid prior to, or during, intake into the manifold, thereby preventing unwanted constituents (e.g. sand, gravel, etc.) within the fluid from entering the manifold.

The inlet ports of the manifold may all have substantially the same flow area. Having inlet ports of substantially the same flow area may seek to ensure a balanced intake between different inlet ports. For example, a common inlet port flow area may assist to ensure that fluids of the same density will flow through each inlet port at substantially the same flow rate (e.g., volumetric flow rate). Providing uniform flow rates through each inlet port of the manifold may further help to ensure that the composition of the fluid delivered at the outlet of the fluid intake system is representative of the composition of the fluid surrounding the tubular. The uniform value for the flow area of the inlet ports may be specifically selected dependent upon the application of the fluid intake system.

The inlet ports may have a common or substantially the same diameter. While the term “diameter” is used with respect to the inlet ports it should be understood that this is used as a term of convenience and that the inlet ports are not limited to being circular ports. While the inlet ports may be circular, they may take any alternative form, such as polygonal, oval, elongate slots etc.

In an alternative example, different inlet ports may have different flow areas (e.g., diameters). The flow area of each inlet port may be selected dependent upon the application of the fluid intake system. For example, in some cases, it may be desirable to encourage greater inflow in some regions of the manifold compared to other regions.

This might be desirable in applications where the deployed orientation of the manifold with respect to a wellbore is known or can be controlled, and a specific stratified fluid layer is to be preferentially received into the manifold.

The flow area (e.g., diameter) of the inlet ports may be selected to perform a specific function, with regards to the overall function of the fluid intake system. For example, the inlet ports of the manifold may be required to provide a pressure drop within the fluid flowing between an environment external to the manifold and the interior of the manifold. Therefore, the flow area (e.g., diameter) of the inlet ports may be an integral factor in a flow control process if pressure manipulation of a fluid is required. In other examples, the flow area (e.g., diameter) of the inlet ports may be selected to have minimal effect on the fluid flowing into the manifold, for example if no or minimal pressure manipulation of the downhole fluid is required to be performed by the manifold.

The diameter of the inlet ports may be within the range of 0.5 mm to 20 mm.

In an example, the tubular may be disposed in a wellbore, creating an annulus between the tubular and the wellbore. The manifold may be disposed around the tubular in the annulus. The manifold may be disposed on or around the tubular in a circumferential manner, or the manifold may generally circumscribe the tubular. As outlined above, it will be appreciated that the terms circumferential/circumscribe are not intended to be limit the manifold to be arranged around a tubular in an exactly circular manner, and that the manifold may be arranged around or partially around the tubular in any form that may generally surround a tubular.

In certain examples, the fluid provided at the outlet of the fluid intake system may flow through a flow control device. In other examples, the fluid provided at the outlet may be delivered to a control arrangement of a flow control device. For example, the fluid provided at the outlet of the fluid intake system may be used in the control or operation of the flow control device. Such control may be improved or made efficient by virtue of the fluid provided at the outlet of the fluid intake system being representative of the original fluid in which the fluid intake system is disposed.

The outlet of the fluid intake system may be fluidly connected to a single flow control device. The outlet of the fluid intake system may be fluidly connected to a plurality of flow control devices, wherein the fluid received by the manifold of the fluid intake system flows to the plurality of flow control devices.

The fluid intake system may comprise a single outlet. Alternatively, the fluid intake system may comprise multiple outlets.

The outlet of the fluid intake system may be disposed directly on the manifold. The outlet may be connected to the manifold via an enclosed fluid channel. In some examples the outlet of the fluid intake system may be provided on an outflow arrangement extending from the manifold. The outlet of the fluid intake system may comprise a flow cap or flow head extending from the manifold.

The outlet may be connected to the manifold via an extended flow path, or the like. The extended flow path may comprise a conduit. The conduit may be formed of any suitable material. The conduit may allow for any form of suitable connection with the manifold and/or the outlet of the fluid intake system.

The extended flow path may be provided in a coil type arrangement. The extended flow path may be provided in a spiral or helix type arrangement. When in these arrangements, the extended flow path may circumscribe a tubular. The extended flow path may be provided as a serpentine flow path. When in this arrangement, the extended flow path may partially circumscribe a tubular. Providing the extended flow path in any of these arrangements may allow for the extended flow path to be of a long length, while only occupying a short ‘point to point’ length between the manifold and the outlet of the fluid intake system.

The extended flow path may be circumferentially arranged around the tubular upon which the manifold of the fluid intake system may be disposed. The extended flow path may partially circumscribe the tubular. The extended flow path may fully circumscribe the tubular. The conduit may circumscribe the tubular in a helical manner. The extended flow path may partially circumscribe the tubular in a serpentine manner. The conduit may be arranged separately from the tubular. The conduit may be integrated with the tubular. As outlined above, the term circumscribe is intended define a component surrounding (or partially surrounding) a tubular, and is not intended to be limited to a component surrounding a tubular in an exactly circular manner.

The extended flow path may be used to manipulate a characteristic of the fluid flowing from the manifold to the outlet. For example, the extended flow path may be used to alter the velocity of the fluid flowing therein. The extended flow path may be used to alter the pressure of the fluid flowing therein (e.g., by applying a pressured drop to the fluid flowing therein).

The changes in velocity and/or pressure of the fluid flowing along the extended flow path may be a function of the length of the extended flow path. The changes may be a function of the density of the fluid. The changes may be a function of the viscosity of the fluid. This may ensure that the flow control device may be controlled autonomously, and may be instantaneously responsive to the composition of the fluid flowing through the manifold and towards the outlet.

Variations in pressure and/or velocity of the fluid flowing along the extended flow path may be established by one or more factors within the understanding of the skilled person. For example, the variations may be caused by the internal diameter of the extended flow path. The variations may be induced by internal surface roughness of the extended flow path. The variations may be caused by a relative roughness of the extended flow path, the relative roughness being the relationship between the internal diameter of the extended flow path and the surface roughness of the internal surface of the extended flow path. These factors, either alone or in combination, may cause different pressure drop effects within fluids with different fluid properties flowing along the conduit. For example, a fluid with a first viscosity may experience a drop in pressure and/or velocity. The drop in pressure and/or velocity along the extended flow path may be larger than with that of a fluid with a second, lesser viscosity. In another example, a fluid with a first density may experience a drop in pressure and/or velocity larger than that provided by a fluid with a second, greater density. The pressure and/or velocity variations along the extended flow path may be dependent on both the viscosity and density of a fluid. The density of a fluid, the viscosity of a fluid, the inner diameter of the extended flow path, the surface conditions (e.g., surface roughness) and the velocity of the fluid may all influence the Reynold's number of a fluid.

Therefore, changes in any of these factors may result in a change of Reynold's number of the fluid.

If a pressure drop is required within the extended flow path, The Darcy-Weisbach equation may be used to determine a characteristic of the extended flow path required to create such a pressure drop. The Darcy-Weisbach equation is shown below;

$\Delta p=\frac{\mathrm{fL}\rho V}{2D}$

wherein Δp is the pressure loss along the length of the extended flow path, f is the friction factor of the extended flow path, L is the length of the extended flow path, V is the velocity of the fluid within the extended flow path and D is the internal diameter of the extended flow path. The length (L₁) of the extended flow path may be selected by rearranging the Darcy-Weisbach equation (wherein the required control pressure within the sealed control pressure chamber and the reservoir fluid pressure are known—providing the required pressure differential, Δp);

$L_1=\frac{\Delta p2D}{f\rho V}$

Further, changes in the Reynold's number of a fluid may influence changes in the friction factor within the extended flow path, in accordance with the known Moody Diagram (wherein the Moody Diagram shows the relationship between the relative roughness of the internal surface of a flow path and the Reynold's number of the fluid flowing within said flow path, with the Moody Diagram providing an overall coefficient of friction within said flow path based on these factors). When considering the friction factor of the conduit, the ratio between the surface roughness of the extended flow path and the inner diameter of the extended flow path, wherein this ratio is named the relative pipe roughness, may also be considered.

The extended flow path may comprise one or more flow restrictions. The one or more restrictions may be configured to alter the pressure within the extended flow path. The one or more restrictions may be configured to provide a desired pressure at the outlet of the fluid intake system. Said pressure at the outlet of the fluid intake system may be used to control a flow control device.

The fluid intake system may comprise a pressure controller configured to manipulate the pressure of the fluid to be communicated to the flow control device. The pressure controller may be located intermediate the manifold and the outlet of the fluid intake system. The pressure controller may be located within and/or connected to an extended flow path of the fluid intake system. The pressure controller may comprise at least one flow restrictor, wherein, during use, at least a portion of the fluid received into the fluid intake system flows through the flow restrictor to undergo pressure manipulation in accordance with known fluid dynamic principles. Such pressure manipulation may generate a desired back pressure condition within the downhole fluid. This fluid backpressure may be delivered or communicated to the flow control device, for example for use in a control operation therein. This back pressure communicated to the flow control device may be defined as a static pressure. This back pressure communicated to the flow control device may be defined as a control pressure.

The flow restriction may define a fluid inlet and a fluid outlet. The fluid inlet may be configured to receive fluid from the manifold (for example via an extended flow path). The fluid outlet may be configured, in use, to be in communication with an exhaust region. In one example the exhaust region may be an interior space of the associated tubular. As such, the pressure manipulation effect applied to the downhole fluid by the flow restrictor may be achieved with reference to the pressure internally of the tubular, which may provide significant benefits in terms of the control operation of an associated flow control device which functions to control the inflow into the same tubular.

The pressure controller may be disposed within the wall of the tubular. The pressure controller may be integrated within a wall of the tubular. The pressure controller may comprise a body portion to be secured within a port, for example a threaded port, in the wall of the tubular. In some examples an associated flow control device may also comprise a body to be secured within the wall of the tubular. In an example the body of the pressure controller and of the flow control device may be substantially identical, thus providing a degree of standardisation, with associated benefits in terms of minimised complexity, costs for bespoke components etc.

The pressure controller may comprise a removable insert. The removable insert may comprise the flow restriction. Having a pressure controller comprising a removable insert, with said insert comprising the flow restriction, may permit the pressure controller to be readily configured with a desired flow restriction prior to deployment, without necessarily requiring the entirety of the pressure controller to be bespoke to a particular operational requirement.

The pressure controller may comprise a valve. The valve may be a non-return valve. The non-return valve may seek to prevent reverse flow through the flow restriction, for example reverse flow from the tubular.

In use, deviations in pressure and/or velocity may be used to provide a desired control pressure at the outlet of the fluid intake system. Said control pressure may be used as part of a control system for a flow control device, as will be described further below.

The fluid intake system may be disposed on a tubular. Said tubular may be a production tubular, for producing fluid from a fluid source. The fluid source may be a subterranean hydrocarbon bearing reservoir, aquifer, or the like.

The manifold of the fluid intake system may fully circumscribe the tubular. The manifold may partially circumscribe the tubular. As outlined above, the term circumscribe is intended to define a manifold that simply surrounds (or partially surrounds the tubular), and is not intended to be limited to surround the tubular in a circular manner.

The manifold may be an integrated component with the tubular. The manifold may be a separate component from the tubular. In some examples, the fluid intake system may comprise a plurality of manifolds, with each manifold circumscribing (or partially circumscribing) the tubular.

In some applications, the manifold may be arranged to circumscribe the tubular at a specific axial location of the tubular, thereby collecting fluid from a specific axial location of the tubular and wellbore. In other applications, the manifold may circumscribe the manifold in an axially distributed manner, such as in a helical manner, wherein the manifold extends axially while still circumscribing (or partially circumscribing) the tubular.

In some applications, the fluid intake system may comprise a temporary barrier to prevent or minimise flow into the manifold, at least while the barrier is in place. The benefit of including a temporary barrier may be that unwanted fluids or materials are prevented from entering the fluid intake system during deployment of the system to its desired location. Once the system has reached its desired location, the barrier may be removed, and fluid may flow freely into the fluid intake system. The temporary barrier may be degradable or dissolvable in order for it to be removed. Removal of the temporary barrier may be initiated by an environmental stimulus. For example, the temporary barrier removed when contacted by a specific fluid. Alternatively, the temporary barrier may be removed in response to a predetermined pressure or temperature. The temporary barrier may be removed by any combination of these factors.

The temporary barrier may comprise a coating and/or covering provided over at least a portion of the manifold. In other examples the temporary barrier may comprise at least one of the inlet ports being occluded by a removable plug. In other examples, the temporary barrier may be provided as a filler material provided within at least a portion of the manifold or the extended flow path, or both.

An aspect of the present disclosure relates to a flow control system, comprising:

• • a flow control device locatable within a wall of a tubular for controlling fluid flow into the tubular; and
  • a fluid intake system comprising:
    • a manifold configured to circumscribe the tubular and comprising a plurality of circumferentially arranged inlet ports for receiving a downhole fluid into the manifold; and
    • a fluid outlet in communication with the flow control device to, in use, communicate downhole fluid from the manifold to the flow control device.

The fluid intake system may be provided in accordance with any other aspect.

The flow control device may comprise an inlet and an outlet, and a flow path extending therebetween. The fluid intake system may be in fluid communication with the inlet of the flow path.

The flow control device may comprise a body. Said body may be locatable within the wall of a tubular. The flow control device may have a valve member disposed within the fluid flow path. The valve member may be moveable in first and second reverse directions to selectively vary a flow area of the flow path. Such variation may include varying levels of restriction. Such variation may include opening and closing the flow path.

Advantageously, the fluid intake system (or fluid collector) may function such that the fluid provided at the inlet of the flow path (and therefore the inlet of the flow control device) may be of the same composition as the fluid prior to intake or collection.

The flow control device may comprise a control system. The fluid intake system may be in fluid communication with the control system. Accordingly, fluid provided to the control system of the flow control device may be of substantially the same composition as the original fluid prior to collection.

The control system of the flow control device may comprise a sealed pilot chamber. The sealed pilot chamber may comprise an inlet for receiving a control pressure. Said control pressure may also be defined as a pilot pressure. The valve member may be in pressure communication with the control system (e.g., in pressure communication with the pilot chamber) such that control pressure may act to bias the valve member in one of the first and second reverse directions.

The flow control device may comprise an inlet and an outlet defining a flow path therebetween, and a control system. The fluid intake system, or at least the manifold of the fluid intake system, may be in communication with both the flow path and the control system. Alternatively, the flow control system may comprise a first fluid intake system in fluid communication with the inlet of the flow control device, and a second fluid intake system in fluid communication with the control system.

As outlined above, when the flow control device is placed within a highly deviated/horizontal wellbore, the inlet of the flow control device itself may only be disposed in a single component/constituent of a fluid that has undergone stratification (as the fluid has separated into each of its constituent parts based on their individual densities). Therefore, having a manifold with a plurality of circumferentially arranged inlet ports allows collection of fluid from each stratified component of the fluid, ultimately providing a fluid with substantially the same composition as the fluid to be passed to the outlet of the fluid intake system, and then the inlet of the flow control device.

The flow control device may use fluid to initiate autonomous control. Therefore, it is important that the fluid at the inlet of the flow control device has the same composition as the original fluid prior to collection (e.g., fluid in a wellbore), to ensure that the flow control device reacts accordingly. As outlined above, when a fluid has undergone stratification, a flow control device with a single inlet may only see a single component of the fluid. For example, if the inlet of the flow control device is only exposed to water that has been stratified from the reservoir fluid, the flow control device may move to a closed (or partially closed) position-when recoverable hydrocarbons may still be present in the wellbore. In contrast to this, when a fluid is provided at the inlet of the flow control device that is of the same composition as the original fluid (e.g. which may still contain recoverable hydrocarbons), the flow control device may be autonomously controlled to move to or maintain a configuration in which said hydrocarbons can still be recovered.

The flow control system may comprise a pressure controller configured to manipulate the pressure of the fluid to be communicated to the flow control device. The pressure controller may be located intermediate the manifold and the outlet of the fluid intake system. The pressure controller may be located within and/or connected to an extended flow path of the fluid intake system. The pressure controller may comprise at least one flow restrictor, wherein, during use, at least a portion of the fluid received into the fluid intake system flows through the flow restrictor to undergo pressure manipulation in accordance with known fluid dynamic principles. Such pressure manipulation may generate a desired back pressure condition within the downhole fluid. This fluid backpressure may be delivered or communicated to the flow control device, for example for use in a control operation therein. This back pressure communicated to the flow control device may be defined as a static pressure. This back pressure communicated to the flow control device may be defined as a control pressure.

The flow restriction may define a fluid inlet and a fluid outlet. The fluid inlet may be configured to receive fluid from the manifold (for example via an extended flow path). The fluid outlet may be configured, in use, to be in communication with an exhaust region. In one example the exhaust region may be an interior space of the associated tubular. As such, the pressure manipulation effect applied to the downhole fluid by the flow restrictor may be achieved with reference to the pressure internally of the tubular, which may provide significant benefits in terms of the control operation of an associated flow control device which functions to control the inflow into the same tubular.

The pressure controller may be disposed within the wall of the tubular. The pressure controller may be integrated within a wall of the tubular. The pressure controller may comprise a body portion to be secured within a port, for example a threaded port, in the wall of the tubular. In some examples the flow control device may also comprise a body to be secured within the wall of the tubular. In an example the body of the pressure controller and of the flow control device may be substantially identical, thus providing a degree of standardisation, with associated benefits in terms of minimised complexity, costs for bespoke components etc.

The pressure controller may comprise a removable insert. The removable insert may comprise the flow restriction. Having a pressure controller comprising a removable insert, with said insert comprising the flow restriction, may permit the pressure controller to be readily configured with a desired flow restriction prior to deployment, without necessarily requiring the entirety of the pressure controller to be bespoke to a particular operational requirement.

The pressure controller may comprise a valve. The valve may be a non-return valve. The non-return valve may seek to prevent reverse flow through the flow restriction, for example reverse flow from the tubular. The valve, e.g. non-return valve, may be degradable and/or dissolvable, for example over a predetermined period of time. This may avoid or mitigate risks that the valve may become stuck or blocked over time.

A further aspect of the present disclosure relates to an inflow control system, comprising:

• • a flow control device locatable within the wall of a tubular for controlling flow of fluid into the tubular, the flow control device comprising a flow path therethrough and a control arrangement; and
  • a first fluid intake system and a second fluid intake system, the first and second fluid intake systems each comprising:
    • a manifold, the manifold configured to circumscribe the tubular, and comprising a plurality of circumferentially arranged inlet ports for receiving a fluid into the manifold; and,
    • a fluid outlet in communication with the flow control device to, in use, communicate fluid from the manifold to the flow control device,
  • wherein the outlet of the first fluid intake system is in fluid communication with the flow path of the inflow control device; and
  • wherein the outlet of the second fluid intake system is in fluid communication with the control arrangement of the flow control device.

The first and/or second fluid intake systems may be provided in accordance with a fluid intake system of any other aspect.

The flow control device may comprise a body. The body may be locatable within the wall of a tubular. The body may be releasably connected to the wall of the tubular. Alternatively, the body of the flow control device may be integrated within the wall tubular.

The body may define an inlet and an outlet of the flow control device. The flow path through the flow control device may be defined between the inlet and the outlet. A valve member may be disposed within the flow path of the flow control device. The valve member may be moveable in first and second reverse directions to selectively vary a flow area of the flow path.

The valve member may be moveable between a fully open position, wherein there is minimal restriction to flow within the primary flow path, and a fully closed position wherein maximum restriction to flow is provided. In some examples some flow may still be permitted when the valve member is in its fully closed position. That is, although the term “closed” is used this should not be understood to also mean fully sealed, unless explicitly indicated otherwise. However, in other examples zero flow may be permitted (or desired) when the valve member is in its fully closed position.

The first fluid intake system may be in fluid communication with the flow path defined through the body of the flow control device. The outlet of the first fluid intake system may be fluidly connected to the flow path of the flow control device.

The control arrangement of the flow control device may comprise a sealed pilot pressure chamber. The control arrangement may be in pressure communication with the second fluid intake system. The control arrangement may be in pressure communication with the outlet of the second fluid intake system. The control arrangement may comprise an inlet for receiving a control pressure from the second fluid intake system. The valve member disposed within the flow path of the flow control device may be in pressure communication with the control arrangement, such that control pressure variations within the control arrangement may act to bias the valve member in one of the first and second reverse directions.

The second fluid intake system may comprise an extended flow path between the manifold and the outlet of the system. The extended flow path may comprise a conduit.

The extended flow path may be provided in a coiled configuration. The extended flow path may be provided in a spiral or helical formation. When in either a coiled or spiral/helical configuration, the extended flow path may fully circumscribe the tubular upon which a flow control device is disposed, as defined above.

The extended flow path may be arranged to extend between the manifold and the outlet of the second fluid intake system in a serpentine manner. When the extended flow path is arranged in this manner, the extended flow path may partially circumscribe the tubular upon which the flow control device is disposed.

The extended flow path may be disposed separately from the tubular. The extended flow path may be an integrated component of the tubular.

The extended flow path may be used to manipulate a characteristic of the fluid flowing from the manifold to the outlet of the second fluid intake system (as outlined above).

For example, the extended flow path may be used to alter the velocity of the fluid flowing between the inlet ports of the manifold and the outlet of the second fluid intake system (as outlined above). The extended flow path may be used to alter the pressure of the fluid flowing between the inlet ports of the manifold and the outlet of the second fluid intake system (as outlined above). The extended flow path may be used to provide a desired control pressure at the outlet of the second fluid intake.

As outlined above, the changes in velocity or pressure of the fluid flowing along the extended flow path may be a function of the length of the conduit. Alternatively, the changes may be a function of the density of the fluid flowing towards the outlet of the second fluid intake system. The changes may be a function of the viscosity of the of the reservoir fluid flowing towards the outlet of the second fluid intake system. The changes may be a combination of any of these factors.

The first and second fluid intake systems may be used in parallel with an inflow control device, in an inflow control system. The first and second fluid intake systems may be used in parallel to autonomously control the flow control device (e.g. by moving the valve member between open and closed positions) of the inflow control system.

For example, when a fluid with a first fluid property (such as a first viscosity) is flowing through the inlet ports of the first fluid intake system, the outlet may be in fluid communication with the inlet of the flow control device. The fluid supplied at the inlet of the flow control device may also apply a pressure to the valve member of the flow control device. At the same time, a fluid with the same properties as that flowing through the inlet ports of the first fluid intake system may also be flowing through the inlet ports of the second fluid intake system. The outlet of the second fluid intake system may be in pressure communication with the control arrangement of the flow control device; wherein said control arrangement may also be in pressure communication with the valve member of the flow control device. Therefore, the valve member within the flow control device may be positioned to allow a first flow rate through the flow control device, dependent upon the pressure differential between the control pressure, and the pressure acting on the valve member from the fluid provided at the inlet of the flow control device.

When a fluid with the second fluid property (such as a second viscosity, wherein the second viscosity differs from the first viscosity), begins to flow through the inlet ports of the first and second fluid intakes, the position of the valve member may be altered to allow a second flow rate through the flow control device (dependent upon the new pressure differential acting across the valve member), wherein the second flow rate differs from the first flow rate. This effect may be advantageous in that an autonomous flow control device may be provided, wherein the flow rate through the valve may be autonomously varied reactive to changes in properties of the fluid flowing through the device; without the need for user input. This may allow for an increased flow rate through the device when a desired product is flowing from a reservoir and into the first and second fluid intake systems, with flow being restricted when an undesired product flows from the reservoir and into the first and second fluid intake systems. Therefore, a flow control device is provided that may vary the flow through the flow control device based upon a property of the fluid flowing through the device, wherein the fluid flowing through the flow control device is of the same composition as that found within the wellbore.

In a specific example, flow through the inlet of the flow control device may oppose any biasing force provided by a control pressure acting in the control arrangement of the flow control device. For example, the control pressure within the control arrangement may act to bias the valve member in the second direction, for example, towards the fully closed position, wherein maximum flow restriction (e.g., minimum flow or zero flow) is established. Therefore, when the flow through the inlet of the flow control device provides a biasing force on the valve member that is greater than the biasing force provided on the valve member by the control pressure within the control arrangement of the flow control device, the pressure differential acting across the valve member may be such that the valve member may be moved to increase the flow area of the flow path through the flow control device (e.g. the valve member may be moved by some increment in the first direction towards the fully open position). The rate at which the valve member may be moved towards the fully open position, and the increment by which it is moved, may be dependent on the magnitude of the pressure differential across the valve member.

Alternatively, when the biasing force acting on the valve member provided by the control pressure exceeds the force acting upon the valve member provided by flow through the inlet of the flow control device, the valve member may be moved in the second reverse direction to decrease the flow area of the flow path of the flow control device (e.g. towards the fully closed position).

Further, by virtue of controlling movement of the valve member via a control arrangement, the first or second fluid intake systems, or the flow control device itself, may not need to be configured to manipulate the fluid via the Bernoulli effect, as is known in the art with devices of this nature. That is, many known inflow control devices seek to operate based on the principle of lift applied on a valve member as a result of the Bernoulli hydrodynamic principle, wherein such lift is varied in accordance with variations on fluid viscosity.

Further, a device that utilises the Bernoulli effect to vary the flow rate through a flow control device may require some form of restrictions to be provided in order to manipulate the fluid to provide a desired effect (e.g. a change in pressure of the fluid). It is an advantage of the present disclosure to autonomously control a flow control device using fluid pressure without the need for restrictions, and manipulation of fluid properties using the Bernoulli effect may not be required.

The second fluid intake system may comprise a pressure controller configured to manipulate the pressure of the fluid to be communicated to the flow control device. The pressure controller may be provided in accordance with that defined in relation to any other aspect.

A further aspect of the present disclosure relates to a pressure controller for use with a flow control device which controls fluid flow into a tubular, the pressure controller comprising:

• • an inlet configured to receive a fluid;
  • a first outlet, the first outlet configured to be in fluid communication with the interior of the tubular;
  • a flow path defined between the inlet and the first outlet, the flow path comprising a flow restriction; and
  • a second outlet in pressure communication with the inlet of the flow path, the second outlet configured to be connected in pressure communication with the flow control device to communicate pressure at the inlet to the flow control device.

The inlet may be configured to receive a fluid from a fluid intake system. The fluid intake system may be provided in accordance with any other aspect. The fluid intake system may comprise a manifold comprising a plurality of circumferentially arranged inlet ports, and an outlet. An extended flow path may be disposed between the manifold and the outlet. The pressure controller may form part of the extended flow path.

The outlet of the fluid intake system may be in fluid communication with the inlet of the pressure controller. In this example, the second outlet of the pressure controller may be in pressure communication with a control arrangement of the flow control device. Alternatively, the second outlet of the pressure controller may be in pressure communication with the outlet of the fluid intake system, wherein the outlet of the fluid intake system is in pressure communication with the control arrangement of the flow control device. In either example, the first outlet may be in fluid communication with the interior of a tubular upon which the pressure controller may be disposed.

During use, at least a portion of the fluid received into the fluid intake system flows through the flow restrictor to undergo pressure manipulation in accordance with known fluid dynamic principles. Such pressure manipulation may generate a desired back pressure condition within the fluid.

The pressure controller may be or incorporate features of a pressure controller defined in relation to any other aspect.

An aspect of the present disclosure relates to a flow control system for delivering a fluid to a flow control device which controls fluid flow into a tubular, the flow control system comprising:

• • a fluid intake system comprising a manifold configured to circumscribe the tubular and comprising a plurality of circumferentially arranged inlet ports for receiving a fluid into the manifold, and a system outlet in communication with the manifold; and
  • a pressure controller comprising:
    • an inlet configured to receive the fluid;
    • a first outlet, the first outlet configured to be in fluid communication with the interior of the tubular;
    • a flow path defined between the inlet and the first outlet, the flow path comprising a flow restriction; and
    • a second outlet in pressure communication with the inlet of the flow path, the second outlet configured to be connected in pressure communication with the flow control device to communicate pressure at the inlet to the flow control device.

As outlined above, using a pressure controller in combination with a fluid intake system in this manner allows a user to configure the pressure/range of pressures required at either the second outlet of the pressure controller, or the outlet of the fluid intake system. In one example, the pressure/range of pressures provided at either the second outlet or outlet of the fluid intake system may be used with the control arrangement of an inflow control valve.

A further aspect of the present disclosure relates to a method of flow control, the method comprising:

• • immersing a manifold in a fluid, said manifold comprising a plurality of circumferentially arranged inlet ports;
  • flowing the fluid into the manifold through the plurality of circumferentially arranged inlets; and,
  • flowing the fluid out of an outlet in fluid communication with the manifold.

The method may be performed using a fluid intake system according to any other aspect.

The outlet may be arranged in fluid communication with a flow control device prior to immersing the manifold in a fluid.

The method may comprise immersing a second manifold in the fluid, wherein the second manifold may also include a plurality of circumferentially arranged inlet ports. Fluid may then flow from the second manifold towards a second outlet. The second outlet may also be configured to also be in fluid communication the flow control device. The second outlet may be configured to be in fluid communication with a control arrangement of the fluid control device. As outlined above, in this configuration, a method of autonomous control of the flow control device may be provided, wherein the autonomous control is dictated by the composition of the fluid flowing from a subterranean reservoir.

In the above aspects various features are described which contain or are engaged with a fluid, such as the described manifold, extended flow path etc. As such, in any of the above described aspects fluid contact surfaces are provided. At least a portion of any of these fluid contact surfaces may comprise or may be provided with a coating. By such provision the coating may interact with a fluid, e.g. a downhole fluid, engaged with, in contact with, flowing against etc. such fluid contact surfaces.

The coating may be provided on any fluid contact surface, such as provided within a fluid intake system, a manifold, an extended flow path, a pressure controller and/or the like, as described above.

In some examples the coating may be provided on a fluid contact surface of a/the fluid intake system, such that the coating may provide an interaction with the fluid prior to being delivered to a flow control device. While the coating may be provided on any fluid contact surface, in some examples the coating may be provided on at least a portion of the extended flow path of the fluid intake system. Typically, the coating may be provided on an internal surface of the extended flow path.

In some examples the coating may be provided on a fluid contact surface of a/the flow control device, e.g. control arrangement thereof. While the coating may be provided on any fluid contact surface, in some examples the coating may be provided on at least a portion of the flow control device upstream of a valve thereof. Typically, the coating may be provided on an internal surface of a/the pilot conduit and/or pilot chamber.

The coating may be applied by any suitable coating method, including, but not limited to, wet deposition, chemical vapor deposition, atomic layer deposition, plasmon enhanced chemical vapor deposition. Advantageously, the thickness variation across at least a portion of the treated surface, e.g. over the entire portion of the treated surface, may be no greater than 50, e.g. no greater than 20 nm.

The coating may be a functional coating. The term “functional coating” is herein understood to mean that the coating may be capable of interacting with a fluid flowing on a surface thereof.

The coating may further provide protection, e.g. against corrosion, to the substrate on which it is applied, e.g. to the extended flow path. For example, the coating may be capable of preventing or reducing corrosion caused by mineral acid, carbon dioxide or caustic substances.

The coating may be capable of preventing or reducing deposition of unwanted substances, e.g. organic substances, for example scale, hydrates, sulfides, mercaptans, paraffin, wax or asphaltene, or the like.

The coating may be capable to preventing or reducing growth of biological materials, e.g. bacteria, fungi or the like.

At least a surface of the substrate, e.g. extended flow path, may be made of metal.

The coating may be or may comprise a foam control coating. The coating may be capable of reducing or may promote reduction of foam within the fluid. The coating may be capable of breaking or may promote breaking of emulsions or multiple-phase compositions within the fluid.

As explained above, the fluid intake system typically comprises a manifold comprising a plurality of circumferentially arranged inlet ports for receiving a fluid into the manifold. If the downhole fluid comprises two or more distinct phases, for example if the fluid is prone to foaming, various inlet ports may facilitate influx of different phases of the fluid. By providing a functional coating on a portion of the fluid intake system, e.g. extended flow path thereof, and/or of the flow control device, e.g. pilot conduit thereof, the coating may help interact with the fluid, e.g. by breaking down the multiple phases into fewer phases and/or into a more homogeneous fluid, for example before the fluid reaches the flow control device.

The coating may comprise or may consist of a polymeric material.

The coating may be hydrophobic. The term “hydrophobic” will be herein understood as referring to a surface having a critical surface tension less than 35 dynes/cm, e.g. less than 20 dynes/cm. Alternatively, the coating may be hydrophilic or omniphobic.

The coating may comprise a polysiloxane coating. The polysiloxane coating may be covalently bound to the substrate, e.g. via an oxygen atom.

The coating may be derived from the condensation of an organosilane or organosiloxane precursor, e.g. on the surface of the substrate. The organosilane or organosiloxane precursor may comprise a non-hydrolysable group which may impart the coating with its functionality and/or property, such as hydrophobicity. The coating may comprise a halogenated polysiloxane, for example polysiloxanes derived from heptadecafluoro-1,1,2,2-tetrahydrodecycl)trimethoxysilane or structural analogues thereof, or tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane or structural analogues thereof.

The coating may comprise a halogenated, e.g. fluorinated, polymer, e.g. a halogenated, e.g. fluorinated, polyolefin such as such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP) copolymer, ethylene tetrafluoroethylene (ETFE) copolymer, polyvinylidene fluoride (PVDF), ethylene chlorotrifluoroethylene (ECTFE) copolymer; or a perfluoroalkoxy alkane (PFA). The coating may comprise other types of polymer such as polyphenylene sulfide (PPS), phenolic epoxy (Hempadur's), or the like.

An aspect of the present disclosure relates to a fluid intake system for use with a flow control device which controls fluid flow into a tubular, wherein at least a portion of the fluid intake system comprises or is provided with a foam control coating.

The coating may be hydrophobic. The coating may be capable of reducing or may promote reduction of foam within the fluid. The coating may be capable of breaking or may promote breaking of emulsions or multiple-phase compositions within the fluid.

The coating may comprise any of the features described in earlier aspects, which are not repeated here, merely for brevity.

An aspect of the present disclosure relates to a method of reducing foam within a fluid or of breaking down multiple phases within a fluid passing through a fluid intake system, the method comprising providing at least a portion of the fluid intake system with a coating.

The coating may be hydrophobic. The coating may be capable of reducing or may promote reduction of foam within the fluid. The coating may be capable of breaking or may promote breaking of emulsions or multiple-phase compositions within the fluid.

The coating may comprise any of the features described in earlier aspects, which are not repeated here, merely for brevity.

Features defined in relation to one aspect may be provided in combination with any other aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a representation of the issues faced by autonomously controlled inflow devices forming the state of the art;

FIGS. 2A and 2B show different views of a fluid intake system;

FIG. 3 is a detailed view of the connection between the fluid intake system if FIGS. 2A and 2B and a flow control device;

FIGS. 4A and 4B show different perspective views of an alternative fluid intake system;

FIGS. 5A and 5B show different perspective views of a further alterative fluid intake system;

FIG. 6 illustrates a flow control system which incorporates a first fluid intake system according to FIGS. 2A and 2B and a second fluid intake system according to FIGS. 5A and 5B;

FIG. 7 shows an example of a flow control device that may be used with the fluid control system of FIG. 6;

FIG. 8 shows a detailed view of a pressure controller that may be used on the fluid control system of FIG. 6;

FIG. 9 illustrates a further example of a flow control system;

FIG. 10 shows an alternative example of a flow control system; and

FIG. 11 shows an embodiment of a method for providing a functional coating on at least a portion of a fluid intake system.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are a depiction of production tubular 200 disposed within a highly deviated (or horizontal) wellbore 250, for collecting downhole fluid 230, 240 via a flow control device 200 disposed within the tubular 220, as currently known in the art.

The fluid 230, 240 (which may be interchangeably defined as wellbore fluid, downhole fluid or reservoir fluid) has been collected into the wellbore 250 as two constituents; water 240 and oil 230. The reservoir fluid 230, 240 has undergone stratification, whereby the oil 230 has separated from the water 240, due to the differing densities of these fluids and the wellbore 250 being highly deviated/horizontal.

The reservoir fluid 230, 240 has been collected into the tubular 220 via the inflow control device 200. From FIG. 1A, it can be seen that the majority of the fluid within the tubular 220 is oil 230, with purely oil 230 flowing through the flow control device 200 due to the stratification of the reservoir fluid. If an autonomous inflow control device (AICD) is being used as the inflow control device 200, the AICD will continue to remain open, as it is desirable to keep producing oil 230 from the reservoir.

As can be seen from FIG. 1B, a point has now been reached where the water 240 content of the stratified reservoir fluid has increased to the level of the inflow control device 200. Again, if an AICD is being used in this application, the AICD will move to a closed position, preventing flow into the production tubular 220 (as producing water 240 from a reservoir 220 is undesirable). As shown in FIG. 1B, however, oil 230 is still present within the wellbore 250, which is not being recovered due to the AICD 200 now being closed. Therefore, production of hydrocarbons still present within the wellbore 250 is being missed due to the location of the AICD 200 on the production tubular 220 and the position of the AICD 200 within the stratified fluid 230, 240. This, therefore, presents a problem with maximising recovery of hydrocarbons within highly deviated/horizontal wells.

It will be appreciated that while only water 240 and oil 230 have been shown in this example, this scenario may apply to any situation where multiple fluids or phases of differing densities are present, such as oil/water/gas, oil/gas, water/gas phase combinations.

FIGS. 2A and 2B show different views of a fluid intake system 10 according to the present disclosure. The system 10 includes a manifold 11, formed of a ring-shaped conduit, which is configured to circumscribe a wellbore tubular, such as production tubing (not shown). As such, in use, the manifold 11 will be immersed in a wellbore fluid (e.g., a fluid produced from a subterranean reservoir) within a wellbore annulus surrounding the tubular. In this example, the manifold 11 is circular in order to circumscribe the wellbore tubular but it should be appreciated that the manifold 11 may be of any shape suitable for surrounding any shape of tubular.

The manifold 11 includes a plurality of circumferentially arranged fluid inlet ports 12 for receiving the wellbore fluid into the manifold 11. The system 10 further includes a flow cap 13 which is fluidly connected to the manifold 11 and includes or defines an outlet 14 of the system 10. As such, wellbore fluid received into the manifold 11 via the inlet ports 12 may be communicated to the outlet 14 via the flow cap 13. Thus, as the manifold may receive fluid from around the circumference of a wellbore (due to the manner in which the inlet ports 12 are arranged on the manifold 11), the fluid intake system 10 can provide a fluid at its outlet 14 that is of substantially the same composition as the wellbore fluid. Having a fluid at the outlet 14 of the fluid intake system that is an accurate representation of the fluid that is actually present in the wellbore has many operational advantages. For example, if the fluid at the outlet 14 of the fluid intake system 10 is being used in the process of autonomous inflow control into a production tubular, the autonomous control system/device will be responsive to a fluid that is a true representation of the wellbore fluid, thereby potentially maximising production of desired fluids (e.g. hydrocarbons) from the wellbore.

Furthermore, the ability to draw fluid from around the full circumference of a wellbore may be such that the orientation of the fluid intake system, and any connected flow control device becomes irrelevant.

As will be described below in further detail, the outlet 14 of the flow cap 13 is configured to be connected to a flow control device (not shown) which functions to control the inflow of the wellbore fluid into the associated tubular. In other examples, the flow cap 13 may not be necessary and the outlet of the fluid intake system 10 may be disposed directly on the manifold 11.

In the present example the manifold 11 is configured to be placed at one axial location relative to a tubular, given the ring-like structure of the manifold 11. It should be appreciated, however, that the manifold 11 may be of a spiral or helix like construction, thereby facilitating the collecting fluid along a length of the tubular 50. In a further example (not shown), multiple manifolds 11 may be placed along the length of a production tubular 50, with all manifolds 11 delivering fluid to a single outlet 14, or multiple outlets.

In the present example, twelve inlet ports 12 are provided. It will be appreciated that any suitable number of inlet ports 12 may be used, sufficient to gather a fluid into the fluid intake system that is representative of the composition of the wellbore fluid. Said number of ports may be anywhere in the range of 2 to 40, and even greater in some examples.

The inlet ports 12 in the present example are also evenly circumferentially distributed around the manifold 11. This may assist with collecting wellbore fluid into the manifold 11 that is more closely representative of the composition as the wellbore fluid within the annulus, as there is no effective grouping or increased density of inlet ports 12 in a certain area of the manifold 11. In other applications, the inlet ports 12 may, however, be unevenly distributed around the manifold 11.

The inlet ports 12 in the present example define a substantially uniform flow area (e.g., diameter). This may assist to ensure a more uniform intake of fluid from all locations around the annulus assisting again to ensure that the composition of the fluid delivered at the outlet 14 of the fluid intake system 10 is representative of the composition of the wellbore fluid. The uniform value for the flow area of the inlet ports 12 may be specifically selected dependent upon the application of the fluid intake system. The inlet ports 12 may have diameter sizes in the range of 0.5 mm to 20 mm, for example. However, in other examples the inlet ports 12 may not all be of the same flow area.

It will be appreciated that the manifold 11 may not fully circumscribe/surround the associated tubular. For example, the manifold 11 may only partially surround the tubular.

The manifold 11 may be formed of any suitable material within the understanding of the skilled person.

FIG. 3 illustrates the fluid intake system 10 of FIGS. 2A to 2D during use, in which the manifold 11 is mounted to and circumscribes a tubular 50 in a wellbore 15, such that the manifold 11 may receive wellbore fluid from an annulus 16 defined between the tubular 50 and the wellbore 15. It will be appreciated that the wellbore 15 may be defined by open hole, casing, liner etc.

A flow control device 20 is mounted within a wall of the tubular 50, wherein the outlet 14 of the flow cap 13 is sealed and secured to the flow control device 20 such that wellbore fluid received by the manifold 11 may be communicated to the flow control device 20. In the present example the flow control device 20 provides a desired degree of control over the flow of the wellbore fluid into the tubular 50. It should be understood that any type or form of flow control device may be provided. In the present example the flow control device 20 includes a flow path 17 extending between an inlet 18 and outlet 19, wherein a control member 21 (e.g., valve disc) is mounted within the flow path 17 and is moveable to vary or control the flow of wellbore fluid into the tubular 50. In some examples the flow control device 20 may function with a degree of autonomy, in that the movement and control provided by the control member 21 is achieved in accordance with one or more properties of the wellbore fluid flowing through the flow path 17. In this respect, the intake system 10 advantageously delivers fluid to the flow control device 20 which is compositionally a more accurate representation of the wellbore fluid in the annulus 16, permitting more accurate or appropriate control of inflow into the tubular 50.

However, in other examples the flow control device may be passive. For example, the flow control device may simply be an inlet port into the tubular 50.

In some examples the flow cap 13 may be omitted, and the manifold 11 may be directly coupled to the inlet 18 of the flow control device 20.

In the present example the fluid intake system 10 together with the flow control device 20 (which may be any flow control device and not limited to the specific form illustrated) may collectively define a flow control system 80.

FIGS. 4A and 4B provide different perspective views of an alternative fluid intake system 60. The fluid intake system 60 includes a manifold 61 configured to circumscribe a tubular and including an array of circumferentially distributed inlet ports 62, similar to the example of FIGS. 2A and 2B. In the present example, however, the manifold 61 is formed of a conduit which includes two closed ends 65, 67, and thus does not form a complete circle/loop. This structure of manifold 61 can also be used with the example of FIGS. 2A and 2B, with the manifold 11 of FIGS. 2A and 2B also being suitable for use with the fluid intake system 60 of FIGS. 4A and 4B. As the manifold 61 of this example is an incomplete loop or ring with two closed ends 65, 67, fluid entering the manifold 61 will flow in a single direction towards an outlet thus assisting in providing a more balanced flow regime.

The intake system 60 includes an outlet 64, in this case disposed at the end of an extended flow path in the form of a conduit 66 which is fluidly connected to and extends from the manifold 61. The functionality of this extended flow path conduit 66 will be explained below in greater detail. The conduit 66 is fluidly connected to the manifold 61 at a branch location 68 midway between the closed ends 65, 67. This central location of this connection may assist to ensure an even or balanced flow regime within the manifold 61. However, in other examples the conduit of the extended flow path 66 may be connected to the manifold 61 at any desired location.

In the present example the conduit 66 extends along a serpentine path which is arranged to partially surround an associated tubular upon which the fluid intake system 60 is disposed. However, in an alternative example, as illustrated in FIGS. 5A and 5B, a fluid intake system 70 may include an extended flow path conduit 76 in the form of a coil which extends between a manifold 71 and an outlet 74. In this example the coiled conduit 76 will fully circumscribe a tubular upon which the fluid intake system 70 is disposed. Any suitable arrangement of the extended flow path within the understanding of the skilled person may be provided.

Providing an extended flow path conduit 66, 76 as in the examples presented is such that a relatively long length of conduit may be packaged within a short axial footprint.

The length of the conduit 66, 76 may be selected to provide a desired pressure at the outlet 64, 74. For example, the required pressure at the outlet 64, 74 may be determined by the Darcy-Weisbach equation, shown below;

$\Delta p=\frac{\mathrm{fL}\rho V}{2D}$

wherein Δp is the pressure loss along the length of the conduit 66, 76, f is the friction factor of the conduit 66, 76, L is the length of the conduit 66, 76, V is the velocity of the fluid within the conduit 66, 76 and D is the internal diameter of the conduit 66, 76. The length (L₁) of the conduit 66, 76 may be selected by rearranging the Darcy-Weisbach equation (wherein the required outlet pressure of the fluid intake system 60, 70 and the reservoir fluid pressure are known-providing the required pressure differential, Δp);

$L_1=\frac{\Delta p2D}{f\rho V}$

This fluid provided at the outlet 64, 74 may be delivered to or otherwise used in a flow control device, or similar device. For example, the pressure at the outlet 64, 74 of the fluid intake system 60, 70 may be used as a control pressure within a control arrangement of a flow control device, as will be described in greater detail below.

The conduit 66, 76 may be formed of any suitable material within the understanding of the skilled person.

FIG. 6 illustrates a flow control system, generally identified by reference numeral 100, mounted on a tubular 50. The flow control system 100 includes a flow control device 102 mounted in a wall of the tubular 50, a first fluid intake system 10 according to the example of FIGS. 2A and 2B and a second fluid intake system 70 according to the example of Figures and 5A and 5B. The first fluid intake system 10 is connected to the flow control device 102 in the same manner illustrated in FIG. 3 and as such wellbore fluid from annulus region 16 will be delivered to the flow control device 102 via the first fluid intake system 10 and then received within the tubular 50.

The outlet 74 of the extended flow path conduit 76 of the second fluid intake system 70 is connected to a pressure controller 30, also mounted in the wall of the tubular 50, with a control or pilot conduit 79 extending between the pressure controller 30 and the flow control device 102. The control or pilot conduit 79 functions to deliver a control pressure to the flow control device 102, wherein the control pressure is used, at least partially, in the control or operation of the flow control device 102 to vary or control inflow of wellbore fluid into the tubular 50. In this respect the control pressure may be established by virtue of both the extended flow path conduit 76 and the pressure controller 30.

Thus, fluid provided from the first fluid intake system 10 is provided at the inlet of the flow control device 102, to flow (or not to flow, dependent on the composition of the fluid) into the tubular 50. The fluid (or the control pressure) provided from the second fluid intake system 70 is provided to a control system (not shown) of the flow control device 102, used in the control of flow through the flow control device 102.

In some examples the flow control device 102 may be provided in accordance with that described in the applicant's co-pending application PCT/EP2021/072427, the disclosure of which is incorporated herein by reference. A diagrammatic illustration of an example form of the flow control device 102 is provided in FIG. 7. The device 102 includes a threaded body 1 to be secured in a threaded port of the tubular 50 (FIG. 6). The device 102 further includes an inlet 2, outlet 3 (or multiple outlets) and a flow path 4 extending between the inlet 2 and outlet 3. A control member in the form of a valve disc 5 is provided within the flow path 4, and is illustrated in an open condition in FIG. 7. The device 102 further includes a pilot chamber 6 behind the valve disc 5 and which is in pressure communication with the control or pilot conduit 79, such that control pressure may be delivered to the pilot chamber 6 and act against the valve disc 5. Thus, the control pressure delivered from the second fluid intake system 70, in combination with any other operational pressures, may be used to control movement of the valve disc 5 and thus the flow rate through the flow control device 102.

In the present example the pilot chamber 6 is sealed, such that flow therethrough is not possible. In this example the control pressure delivered to the pilot chamber 6 from the second fluid intake system may be defined as a static pressure.

In the present example the pressure controller 30 may form part of the second fluid intake system 70. The functionality of the pressure controller 30, and its role within the flow control system 100 will be explained in greater detail below. It will be appreciated that a pressure controller 30 may not be essential to providing a desired control pressure at the outlet 74 of the second fluid intake system 70.

Although the second fluid intake system 70 is provided in accordance with the example of FIGS. 5A and 5B, the intake system 60 of FIGS. 4A and 4B may alternatively be used in the system 100 of FIG. 6.

FIG. 8 is a cross-sectional view of the pressure controller 30 of FIG. 6. The pressure controller 30 comprises a threaded body 42 which is configured to be secured to a threaded port on the wall of the tubular 50. This threaded body may be of substantially the same form as threaded body 1 of the flow control device 102 of FIG. 7, thus providing a degree of standardisation.

The pressure controller 30 includes an inlet 31 connected to the extended flow path conduit 76 of the second fluid intake system (FIG. 6), a first outlet 32 which opens into the interior of the tubular 50, and a second fluid outlet 33 connected to the pilot conduit 76. The pressure controller 30 includes a plenum chamber 34, wherein the fluid inlet 31 and the second fluid outlet 33 are both in fluid communication with the plenum chamber 34. It should be noted that the means of fluid communication between the fluid inlet 31 and the plenum chamber 34 is visible in the sectional plane of FIG. 8 (flow path 36). However, the full communication path between the second fluid outlet 33 and the plenum chamber 34 is not visible in FIG. 8 (i.e., out of the plane of cross-section), and is instead represented by dashed line 38.

The pressure controller 30 includes a flow restriction 40 in a restrictor flow path extending between the plenum chamber 34 and the first outlet 32. In use, fluid delivered to the pressure controller 30 via conduit 76 will flow into the plenum chamber 34, through the flow restriction 40 and into the tubular 50 via the first outlet 32. Accordingly, a back pressure will be created within the plenum chamber 34 which will have an association or relationship with the geometry of the restriction 40, the fluid pressure delivered via conduit 76 and the pressure within the tubular 50. The pressure within the plenum chamber 34 is thus communicated to the flow control device 102 (FIG. 6) via the pilot line 79.

In the present example the flow restriction 40 is provided as a removable insert 44 securable with the body 42. The insert 44 may be readily changed in order to provide a different flow restriction and thus a different level of pressure control.

The pressure controller 30 may comprise a non-return valve, comprising a ball 46 and a seat 48. In use, the non-return valve may prevent or restrict reverse flow from the tubular 50. In an embodiment, the non-return valve, e.g. ball 46 and/or seat 48, may be degradable and/or dissolvable, for example over a predetermined period of time. This may avoid or mitigate risks that the valve may become stuck or blocked over time.

FIG. 9 shows the inflow control system 100 as described with respect to FIGS. 6 to 8 disposed upon a tubular 50, with a screen 90 surrounding the inflow control system 100. In use, the screen 90 is used to filter any unwanted materials from the wellbore fluid prior to the fluid reaching either manifold 11 or manifold 71.

FIG. 10 illustrates an alternative example of a flow control system 300 wherein a single fluid intake system 110 is used to provide fluid flow through a flow control device (which is configured in accordance with device 102 of FIG. 7) into the tubular, and a control (or static) pressure for use in controlling the flow control device 102. In this example, fluid from the fluid intake system 110 passes from a manifold 111 (with a circumferential array of inlet ports similar to the examples described above) to a first outlet 114 provided on a flow cap 113, which is in fluid communication with the inlet 2 of the flow control device 102 (as described above).

In this example, the flow cap 113 also defines a secondary outlet port 190, to which an extended flow path conduit 56 is connected. The extended flow path conduit 56 may be provided in accordance with conduits 66 and 76 set out in previous examples, and extends to a pressure controller 30, as described above. Therefore, a portion of wellbore fluid collected by the fluid intake system 110 will flow along a first flow path FP1 to the pressure controller 30.

The fluid from the first flow path FP1 then interacts with the pressure controller 30, as outlined above, with a portion of the fluid bleeding into the tubular 50 via flow restriction 40 along a second flow path FP2 to generate a required back pressure which is communicated along a pressure path PP, to act as a static pressure for control of the flow control device 20.

More specifically, the pressure path PP is defined by pilot conduit 79 between the second outlet 33 of the pressure controller 30 and the flow control device 102, specifically the pilot chamber 6 of the flow control device 102.

In the examples set forth above various features are identified which will come into contact with the fluid. Such features may be defined as fluid contact surfaces. In some examples one or more fluid contact surfaces may include a functional coating. For example, the example extended flow paths of the intake systems may include a functional coating.

Referring to FIG. 11, there is shown an example of a method for providing such a functional coating on a fluid contact surface, such as within an extended flow path and/or pilot conduit. In this example, the coating is a polysiloxane coating, as shown in FIG. 11(a), which is covalently bound to the substrate (i.e., the fluid contact surface).

As shown in FIG. 11(a) the method comprises providing an organosiloxane or organiosilane precursor, which in this embodiment is a trimethoxysilane. However, it will be understood that other organosilane precursors may be envisaged, so long as they include hydrolysable groups and at least one non-hydrolysable group providing the desired functionality to the final coating. Such precursors may be represented by the generic formula (i) below:

R—(CH₂)_n—Si—X₃  Formula (I)

• • wherein:
    • R is a functional (e.g. hydrophobic) group;
    • n is typically between about 1-50, e.g. 2-24;
    • X is a hydrolysable group, optionally independently an alkoxy, acyloxy, halogen or amine group.

R may be a hydrocarbyl group, e.g. an akyl group.

Referring again to FIG. 11(a), there is a shown a first step of the method, which is a hydrolysis step. In this step, a trimethoxysilane precursor is provided in the region of the substrate to be coated. An aqueous medium is provided to initiate hydrolysis. The aqueous medium, e.g. water, may be added, may be present on the substrate surface, or may come from the atmosphere.

The degree of polymerization of the silane species may be determined by the amount of water available and the organic substituent. If the silane is added to water and has low solubility, a high degree of polymerization is favored. Multiple organic substitution, particularly if phenyl or tertiary butyl groups are involved, favors formation of stable monomeric silanols.

As illustrated in FIG. 11(b), following initial hydrolysis, condensation of the precursor into polysiloxane oligomers occurs.

It will be understood that, although FIG. 11 describes the individualised steps sequentially for clarity, these reactions can occur simultaneously following the initial hydrolysis step.

As shown in FIG. 11(c) the oligomers then binds to the substrate via hydrogen bonds.

Finally, as shown in FIG. 11(d), a covalent linkage can be formed between the polysiloxane coating and the substrate. This may typically be achieved via drying and/or curing.

The resulting structure allows the function “R” group to be capable of interacting with a fluid, e.g. with the downhole fluid passing though the fluid intake system. Advantageously, when the “R” group is a hydrophobic group, the coating may be capable of reducing or promoting reduction of foam within the fluid, and/or of breaking emulsions or multiple-phase compositions within the fluid.

It should be understood that the examples described herein are merely exemplary and that various modifications may be made thereto within the understanding of the skilled person, without departing from the scope of the present disclosure. For example, in the examples provided above fluid intake systems are used to deliver fluid to a flow control device which functions to provide a degree of control over a fluid flowing therethrough. However, in other examples the fluid intake system may deliver fluid to an inlet of any fluid system, such as a simple inlet port (without fluid control capabilities) associated with a tubular.

Claims

1. A fluid intake system for use with a flow control device which controls fluid flow into a tubular, the fluid intake system comprising:

a manifold configured to circumscribe a tubular which includes a flow control device, the manifold comprising a plurality of circumferentially arranged inlet ports for receiving a fluid into the manifold; and

a fluid outlet to be arranged in communication with the flow control device to, in use, communicate fluid from the manifold to the flow control device.

2. The fluid intake system according to claim 1, wherein the inlet ports are evenly circumferentially distributed on or about the manifold.

3. The fluid intake system according to claim 1, wherein the inlet ports each have substantially the same flow area.

4. The fluid intake system according to claim 1, wherein the manifold is formed of a conduit.

5. The fluid intake system according to claim 1, wherein the manifold fully or partially circumscribes the tubular.

6. The fluid intake system according to claim 1, wherein the manifold defines a manifold flow path therein, the plurality of inlet ports opening into said manifold flow path.

7. The fluid intake system according to claim 6, wherein the manifold flow path extends between closed ends.

8. The fluid intake system according to claim 7, wherein the fluid outlet is in communication with the manifold at a midpoint between the closed ends.

9. The fluid intake system according to claim 1, configured to be immersed in a wellbore fluid within a wellbore annulus.

10. The fluid intake system according to claim 1, comprising an outlet arrangement fluidly connected to the manifold and defining the fluid outlet.

11. The fluid intake system according to claim 10, wherein the outlet arrangement comprises a flow cap.

12. The fluid intake system according to claim 10, wherein the outlet arrangement comprises an extended flow conduit.

13. The fluid intake system according to claim 12, wherein the extended flow conduit at least partially circumscribes the tubular.

14. The fluid intake system according to claim 12, wherein the extended flow conduit is provided in at least one of a coiled or serpentine form.

15. The fluid intake system according to claim 12, wherein the extended flow conduit is configured to manipulate a characteristic of the fluid flowing from the manifold to the outlet.

16. The fluid intake system according to claim 15, wherein the characteristic includes at least one of fluid pressure and fluid velocity.

17. The fluid intake system according to claim 15, wherein the extended flow conduit is configured to manipulate a characteristic of the fluid flowing from the manifold to the outlet as a function of one or more of the length of the extended flow conduit, the diameter or flow area of the extended flow conduit, the surface roughness of the extended flow conduit, the relative roughness of the extended flow conduit, the density of the fluid and the viscosity of the of the fluid.

18. The fluid intake system according to claim 1, comprising a pressure controller configured to manipulate the pressure of the fluid to be communicated to the flow control device.

19. The fluid intake system according to claim 18, wherein the outlet arrangement comprises an extended flow conduit, and wherein the pressure controller is in communication with the extended flow conduit.

20. The fluid intake system according to claim 18, wherein the pressure controller comprises at least one flow restrictor, wherein, during use, at least a portion of the fluid received into the fluid intake system flows through the flow restrictor.

21. The fluid intake system according to claim 20, wherein the flow restrictor generates a back pressure within the fluid, wherein the back pressure is communicated to the flow control device.

22. The fluid intake system according to claim 1, comprising a coating for interacting with the fluid flowing through the fluid intake system.

23. The fluid intake system according to claim 22, wherein the coating comprises a foam control coating.

24. The fluid intake system according to claim 22, wherein the coating is capable of breaking or promoting breaking of emulsions or multiple-phase compositions within the fluid.

25. The fluid intake system according to claim 22, wherein the coating is provided on at least one of the manifold and an extended flow conduit connected to the manifold.

26. The fluid intake system according to claim 22, wherein the coating comprises a polysiloxane coating.

27. The fluid intake system according to claim 1, wherein the fluid intake system comprises a temporary barrier to prevent or minimise flow into the fluid intake system while the barrier is in place.

28. A flow control system, comprising:

a flow control device locatable within a wall of a tubular for controlling fluid flow into the tubular; and

a fluid intake system comprising:

a manifold configured to circumscribe the tubular and comprising a plurality of circumferentially arranged inlet ports for receiving a downhole fluid into the manifold; and

a fluid outlet in communication with the flow control device to, in use, communicate downhole fluid from the manifold to the flow control device.

29. The flow control system according to claim 28, wherein the flow control device comprises an inlet, an outlet, and a flow path extending between the inlet and the outlet, wherein the fluid intake system is in fluid communication with the inlet of the flow path.

30. The flow control system according to claim 29, wherein the flow control device comprises a valve member disposed within the fluid flow path, the valve member being moveable in first and second reverse directions to selectively vary a flow area of the flow path.

31. The flow control system according to claim 28, wherein the flow control device comprises a control arrangement for controlling flow through the flow control device, wherein the fluid intake system is in fluid and/or pressure communication with the control arrangement.

32. The flow control system according to claim 31, wherein the control arrangement comprises a sealed pilot chamber, in fluid and or pressure communication with the outlet of the fluid intake system.

33. The flow control system according to claim 28, wherein the flow control device comprises an inlet, an outlet and a flow path therebetween, and a control arrangement.

34. The flow control system according to claim 33, wherein the fluid intake system is in communication with both the inlet and the control arrangement of the flow control device.

35. The flow control system according to claim 33, wherein the fluid intake system is a first fluid intake system in fluid communication with the inlet of the flow control device, and the flow control system comprises a second fluid intake system in fluid and/or pressure communication with the control arrangement.

36. The flow control system according to claim 28, comprising a pressure controller configured to manipulate the pressure of the fluid to be communicated to the flow control device.

37. The flow control system according to claim 28, comprising a coating for interacting with the fluid flowing through the fluid intake system.

38. The flow control system according to claim 37, wherein coating comprises a foam control coating.

39.-40. (canceled)

41. An inflow control system, comprising:

a flow control device locatable within the wall of a tubular for controlling flow of fluid into the tubular, the flow control device comprising a flow path therethrough and a control arrangement; and

a first fluid intake system and a second fluid intake system, the first and second fluid intake systems each comprising:

a manifold, the manifold configured to circumscribe the tubular, and comprising a plurality of circumferentially arranged inlet ports for receiving a fluid into the manifold; and,

a fluid outlet in communication with the flow control device to, in use, communicate fluid from the manifold to the flow control device, wherein the outlet of the first fluid intake system is in fluid communication with the flow path of the inflow control device; and wherein the outlet of the second fluid intake system is in fluid communication with the control arrangement of the flow control device.

42. (canceled)

43. A flow control system for delivering a fluid to a flow control device which controls fluid flow into a tubular, the flow control system comprising:

a fluid intake system comprising a manifold configured to circumscribe the tubular and comprising a plurality of circumferentially arranged inlet ports for receiving a fluid into the manifold, and a system outlet in communication with the manifold; and

a pressure controller comprising:

an inlet configured to receive the fluid;

a first outlet, the first outlet configured to be in fluid communication with the interior of the tubular;

a flow path defined between the inlet and the first outlet, the flow path comprising a flow restriction; and

a second outlet in pressure communication with the inlet of the flow path, the second outlet configured to be connected in pressure communication with the flow control device to communicate pressure at the inlet to the flow control device.

44.-49. (canceled)