INFLOW CONTROL DEVICE

[0001]The present invention relates to hydrocarbon production systems, and more specifically to an inflow control device used in a well system, a smart well system, or an advanced well system.

BACKGROUND

[0002]In an effort to improve the production and recovery of oil and gas reservoirs, well completion methods and systems have become increasingly complex over recent years. Conventional vertical wells are being replaced with horizontal and/or multilateral wells with greater well reservoir contact. Whilst such structures can enjoy an improvement in production efficiency, they are also more costly and complicated to drill and install. After installation, variations in reservoir pressure and/or the well-known “heel-toe” effect can cause non-uniform inflow along the well, which can result in early gas and/or water breakthrough. As such, these complicated well structures cannot be efficiently controlled via a surface wellhead choke. Instead, inflow is controlled downhole.

[0003]A number of different inflow-restriction systems have been proposed in the background art. These can be categorised broadly into three categories: passive, active and reactive.

[0004]In a passive system, inflow control devices (ICD) are used to restrict inflow to differing degrees along a producing interval in a well. ICDs comprise nozzles or channels, which restrict the flow of fluid. The degree of restriction is sometimes known as the ICD “strength”. There are various different types of ICD, including nozzle, orifice, helical and labyrinth. The basic working principle is to vary the strength of each ICD along the base string in such a way as to produce a more uniform inflow. The strength of the ICD is set by the geometry and dimension of the fluid channel and is therefore fixed after installation. The resulting system is passive and unable to adapt to dynamic changes. These fluid channels, and therefore the ICDs, cannot be closed.

[0005]In a reactive system, autonomous inflow control devices (AICD) or autonomous inflow control valves (AICV) are used, which are able to self-adjust to restrict unwanted fluid flows, depending on the viscosity and density of the reservoir fluid. AICD/AICV-based systems can be designed to reduce/prevent the flow of water and/or gas and increase/allow the flow of oil.

[0006]In an active system, the well completion structure is divided into zones using packers and the inflow of each zone is controlled using an inflow control valve (ICV) located on the inside of a sandscreen or perforated liner.

[0007]U.S. Pat. No. 9,376,892 discloses an actuation device comprising a housing comprising one or more ports, a magnetic valve component, and a central flowbore. The central flowbore is configured to receive a disposable member configured to emit a magnetic field, and the magnetic valve component is configured to radially shift from a first position to a second position in response to interacting with the magnetic field.

[0008]In any of the aforementioned type of inflow-restriction system, isolation packers may be present to compartmentalize the reservoir into sections.

STATEMENT OF INVENTION

[0009]According to a first aspect of the invention, there is provided an inflow control device for use in a well or pipeline, the inflow control device being configured to switch reversibly between an open state and a closed state, or between a closed state and an open state, the inflow control device comprising: a housing; a gate moveable within the housing between a closed state and an open state; the housing defining a first valve seat for receiving the gate in a closed state, and a second valve seat for receiving the gate in an open state, wherein the first valve seat and the second valve seat comprise one or more permanent magnets, or wherein the gate comprises one or more permanent magnets.

[0010]The inflow control device may further comprise one or more electromagnets arranged within the housing, wherein a magnetic field generated by the one or more electromagnets has a first polarity controllable by an electric current in the electromagnets, wherein the one or more permanent magnets have a second polarity, and wherein the first polarity and second polarity have the same direction in a first direction of the electric current, and have an opposite direction in a second direction of the electric current. A resonant circuit may be provided, arranged to receive electromagnetic energy emitted by a mobile controller, and to electrically energise the one or more electromagnets.

[0011]The gate may define a central opening, and the central opening may be part of a fluid communication channel in the open state. The gate may have sidewalls which block the fluid communication channel in the closed state.

[0012]The gate may define side openings which can be selectively aligned with side openings in an insert of the housing extending into the gate.

[0013]The inflow control device may further comprise a landing arrangement configured to spatially separate the one or more permanent magnets from their respective valve seats.

[0014]The gate may define two opposing faces with substantially equal surface area, when projected onto a transverse plane of the inflow device.

[0015]According to a second aspect of the invention, there is provided a wireline mobile controller, arranged to open or close an inflow control device installed in a well, the mobile controller comprising: a first connector for electrically connecting the mobile controller to a wireline, and a second connector for mechanically connecting the mobile controller to the wireline; an electrical component, arranged to couple electromagnetically to the inflow control device when the electrical component is electrically energised, and to open or close the inflow control device remotely.

[0016]The electrical component may comprise two electromagnets, arranged substantially co-axially around a core, and, in use, arranged to generate two corresponding magnetic fields with opposite polarities. The two electromagnets may be arranged along a longitudinal axis, and the longitudinal axis may substantially coincide with the main axis of a bore of the well in use.

[0017]Centralisers may be provided for centralising the mobile controller within the well.

[0018]The electrical component may comprise an electromagnetic transmitter, arranged to emit an electromagnetic pulse, and an electronic circuit to send an electronic signal to the transmitter for emitting the electromagnetic pulse.

[0019]The electromagnetic transmitter and the electronic circuit are arranged to generate at least two electromagnetic pulses, wherein a first electromagnetic pulse has a different frequency than a second electromagnetic pulse.

[0020]According to a third aspect of the invention, there is provided a method of controlling inflow into a well, the method comprising, providing an inflow control device for use in a hydrocarbon producing well, the inflow control device being configured to switch reversibly between an open state and a closed state, or between a closed state and an open state, the inflow control device comprising: a housing; a gate comprising one or more permanent magnets and moveable within the housing between a closed state and an open state; the housing defining a first valve seat for receiving the gate in a closed state, and a second valve seat for receiving the gate in an open state, wherein the first valve seat and the second valve seat comprise one or more magnetisable portions, moving a mobile controller through a bore of the well, wherein the mobile controller comprises a first connector for electrically connecting the mobile controller to a wireline, and a second connector for mechanically connecting the mobile controller to the wireline; an electrical component, arranged to couple electromagnetically to the inflow control device when the electrical component is electrically energised, and to open or close the inflow control device remotely, opening or closing the inflow control device by electrically energising the mobile controller.

[0021]The energising the mobile controller may generate one or more electromagnetic pulses emitted by the mobile controller, wherein said electromagnetic pulses are received by a resonant circuit provided at the inflow control device, wherein the resonant circuit energises an electromagnet provided within the inflow control device to attract or repel said gate comprising one or more permanent magnets.

[0022]The method may further comprise receiving a signal from a measurement device provided on the wireline, and controlling the electric current in response to said signal.

[0023]The measurement device may measure one or more of: inflow rate, fluid phase, temperature or conductivity of inflow fluid.

[0024]Measuring the fluid phase may comprise measuring an inflow of water or gas into a well, and closing the inflow control device in response to said measuring of the water or the gas.

BRIEF DESCRIPTION OF THE FIGURES

[0025]Embodiments of the invention will now be described for example only with reference to the following drawings in which:

[0026]FIG. 1 is a vertical cross section through a schematic of an inflow control device;

[0027]FIG. 2 is a vertical cross section through a schematic of an inflow control device;

[0028]FIG. 3 is a vertical cross section through a schematic of an inflow control device;

[0029]FIG. 4 is a vertical cross section through a schematic of an inflow control device;

[0030]FIG. 5 is a vertical cross section through a schematic of a mobile controller;

[0031]FIG. 6 is a vertical cross section through a schematic of mobile controller within a pipe section;

[0032]FIG. 7 is a vertical cross section through a schematic of a well system with a sandscreen, a mobile controller and an inflow control device;

[0033]FIG. 8 is a schematic illustration of various aspects of a valve using a resonant circuit to couple to a mobile controller;

[0034]FIG. 9 illustrates schematically alternative designs of an inflow control device;

[0035]FIG. 10 illustrates schematically alternative designs of an inflow control device;

[0036]FIG. 11 is a method flow diagram.

DETAILED DESCRIPTION

[0037]The inflow control device (ICD) described herein is opened or closed magnetically. The device is stable both in the closed position and in the open position, and will remain in the open or closed position unless the electromagnetic force is activated for the purpose of switching between the open and closed states. The gate of the inflow control device is pressure balanced by the area of the gate exposed to fluid pressure being substantially the same in the open position, the closed position, and in between open and closed positions.

[0038]The device may be used in a hydrocarbon producing well, or an injection well. The flow of fluids may go from a reservoir into a wellbore, or the other way around. The words ‘inflow’ or ‘outflow’, or ‘inlet’ and ‘outlet’, may therefore be used interchangeably herein.

[0039]The device comprises a gate, which can be moved between open and closed positions. A first valve seat is provided for receiving the gate in a closed position, and a second valve seat is provided for receiving the gate in an open position. When received in the first or second valve seats, a biasing means is provided to secure the gate in a stable position.

[0040]The biasing means can be mechanical. A first example of a mechanical biasing means is a tapered internal diameter of the seat. When the gate moves towards the narrow end of the tapered internal diameter, the gate will become ‘stuck’ by a friction fit. The friction fit can be overcome by the electromagnetic force, which will be described below. A second example of a mechanical biasing means is a resiliently deformable O-ring provided within the internal wall of the seat. There are many known examples of suitable O-rings, made of PTFA, Neoprene, EPDM rubber or the like. When the gate is received within the O-ring, the deformable material will hold the gate in place. The electromagnetic force is large enough to move the gate out of the seat with the resiliently deformable O-ring.

[0041]The biasing means may be magnetic. A permanent magnet is provided in the gate, and a ferromagnetic material is provided within the seat. An electromagnetic force onto the permanent magnet applied by an external controller will be large enough to overcome the magnetic force. As there are two seats, various permutations of magnets and/or mechanical biasing means are possible.

[0042]The electromagnetic force for switching between the open and closed states is provided by an electromagnet arranged within an external mobile controller acting on a permanent magnet arranged within the gate. The electromagnet comprises one or more windings of electrically conducting material, which provides a magnetic field when an electric current travels through the conducting material. The direction of the magnetic field can be switched by switching the direction of the electric current.

[0043]A central axis of the field of the permanent magnet is aligned with a portion of the magnetic field of the electromagnet that has relatively uniform and strong magnetic field lines, but the polarity of the electromagnet can be switched between being in opposite direction or being in the same direction to cause switching. The permanent magnet in the gate has a fixed direction, so when the direction of the current is switched, the gate can be switched between open and closed position.

[0044]The housing is designed such that in the open position the gate provides an open channel between the inlet and outlet of the device, while in the closed position, the gate blocks the path between the inlet and outlet, thereby closing the device. Although various arrangements are possible to achieve the same effect, a specific embodiment will now be described.

[0045]FIG. 1 shows a vertical cross section through a schematic drawing of the inflow control device. A housing 1 is provided, which is preferably made of a non-magnetic material. An inlet 2 (or nozzle) is provided within the housing. The inlet is made of a non-magnetic material and is preferably removably attached to the housing. The inlet can be fixed by way of a screw-fit, for example. The inlet will be subject to a significant amount of wear due to the inflow of sand, debris or other hard materials. By providing a replaceable inlet, the lifetime of the device can be increased. If the inlet is accessible during use or after use, the inlet can be replaced. However, during typical use the inlet is not easily accessible after well completion. In that case, the lifetime of the device can be increased by using a different material for the inlet than for the other parts of the device, preferable a hard-wearing material; examples are known to the skilled person.

[0046]A gate 3 is provided within the housing. In the illustrated arrangement, the main body of the gate 3 is made of a non-magnetic material. The housing defines a generally tubular internal cavity and receives a generally cylindrical gate, which can move within the tubular internal cavity between a closed and open position. The gate includes a permanent magnet 4 at the top of the gate, and the direction of the field is north up and south down in the orientation of the device shown in the figure. This polarity should be not viewed as limiting, but merely exemplary; the skilled reader would appreciate that the inflow control device may instead operate in substantially the same way with the permanent magnet being of opposite polarity (north down and south up in the figure).

[0047]FIG. 1 illustrates the gate in the open position. The gate defines a central channel, which is aligned with the opening of inlet 2. The fluid path, defined by the inlet and the central channel of the gate, continues underneath the gate in the open position and then continues to an outlet 7 provided in circumferential direction of the housing. The outlet may be continuous around the circumferential direction, but preferably is interrupted by one or more connections between the main part of the housing and a bottom part of the housing.

[0048]A ferromagnetic insert 8 is provided within the internal cavity of the housing at the top, adjacent to permanent magnet 4 of the gate to bias the gate in the open position. A second ferromagnetic insert 9 is provided within the bottom part of the housing and adjacent a further permanent magnet 10 provided within the gate at the bottom part of the gate in the closed position.

[0049]In the open position, the gate will be stable because of the attraction between permanent magnet 4 and ferromagnetic material 8, and no external magnetic field is required until opening of the device is required.

[0050]A landing arrangement 11 is provided between the permanent magnet 4 and ferromagnetic insert 8 for improved sealing, to avoid a vacuum seal between the flat surfaces of the permanent magnet 4 and ferromagnetic insert 8, and to avoid the magnetic force between parts 4 and 8 being too large to overcome. Another technical effect of the landing arrangement is that it allows pressure communication through the small fluid layer between the gate and the adjacent seat. The pressure communication enables the gate to be pressure balanced, due to the area exposed to fluid pressure being the same in the open position, the closed position, and in between.

[0051]FIG. 1 illustrates the device in the open state, and FIG. 2 illustrates the same device in the closed state. The fluid path to outlet 7 is now blocked by the gate. The gate is received in the seat provided by landing arrangement 12 and is in a stable position due to the attractive force between the permanent magnet 10 and ferromagnetic insert 9.

[0052]The top 13 of the housing has a frusto-conical shape to improve the smooth fluid flow towards the inlet. The top is also slightly wider than the main part of the housing, and the overhang 14 improves the seal and connection when set into an opening in a screen or pipe. The overhang 14 can engage with a corresponding shoulder of the opening.

[0053]The directions in this description of the figures make use of the words ‘up’, ‘down’, ‘top’ and ‘bottom’, but it will be appreciated that these directions are only relevant in relation to the orientation shown in the figure. The device can have any orientation during use, including the reverse, ‘upside-down’ orientation, when compared to how it is represented in the figures.

[0054]FIG. 3 illustrates a device which generally corresponds to the device shown in FIGS. 1 and 2, but the outlet has a slightly different shape. Figure A illustrates the open position, while figure B illustrates the closed position. The outlet channel 31 has a diagonal direction, while the outlet in FIGS. 1 and 2 is an inverted L-shape including a corner. The main advantage of this direction is that the corner is avoided and machining of the outlet during manufacturing is easier.

[0055]FIG. 4 illustrates a further device in open and closed configuration. The difference over the device in the preceding figures is that the gap between the gate and the generally tubular internal cavity of the housing is slightly bigger. The gap is sealed by multiple seals 41. The provision of seals requires an additional element, but on the other hand the tolerances for manufacturing the housing and the gate can be slightly larger. The seals can be made of a resiliently deformable material suitable for use in a well, which the skilled person is aware of.

[0056]Although in the illustrated examples a set of two magnets is used for the gate, the gate could also comprise a single magnet, multiple distributed magnets, or the gate may be a magnet itself without there being other components to the gate. The size of the magnets may also be different than illustrated.

[0057]FIG. 5 illustrates the mobile controller used for opening and closing the device. The mobile controller comprises an electromagnet 51. The position, power supply and control signal are provided to the electromagnet by wireline 52. The electromagnet comprises a soft magnetic core 53, surrounded by two sets of coils 54, 55. The electric current through one of the two coils is opposite to the electric current through the other one of the two coils, and the two coils therefore create magnetic fields with opposite polarity. One set of poles therefore overlaps, whether both north poles, as illustrated in FIG. 5A, or both south poles, as illustrated in FIG. 5B. FIG. 5C illustrates a vertical cross section along dashed line L shown in FIG. 5A. The cross section of the core is shown as being circular, but other shapes may also be used such as square or rectangular. The magnetic field lines spread radially outwards uniformly across all angles, as illustrated in FIG. 5C. The mobile controller can therefore be used in any rotational orientation. It is possible to switch between the field of FIGS. 5A and B by reversing the direction of the current in both coils.

[0058]The technical effect of using two opposite magnetic fields is two-fold: the density of the magnetic field lines across line L is significantly higher than if a single magnet is used, and the density at the centre is significantly higher than the density of the opposite poles at both ends of the mobile controller. In the FIG. 5A illustration, the density of the central north pole field lines is much higher than the density of the field lines of the south poles on both ends of the device. The same is true for the FIG. 5B illustration, but then the other way around, with the strong south pole field lines in the centre, and the weaker north pole field lines at the outsides. When used for switching a magnetic valve, the threshold of magnetic field strength at which the permanent magnetic second body switches position is chosen such that the central magnetic field lines are above the switching threshold, while the magnetic field density of the opposite poles is below the switching threshold. This avoids the field of the opposite poles reversing the switching carried out by the central field.

[0059]The strength of the central magnetic field relative to the end poles can further be increased by increasing the overall length of the electromagnet, or by reducing the diameter of the electromagnet towards the two ends.

[0060]If the use of a threshold is too difficult in some practical scenarios, for example if the distance between the mobile controller and the inflow control device cannot be controlled easily due a strong fluid flow, the odd number of poles can be used to cause an effective overall switch: the two south poles and one north pole of FIG. 5A (or two north poles and one south pole of FIG. 5B), would cause an odd sequence of switches when the mobile controller passes the ICD-‘up-down-up’, or ‘down-up-down’, thereby causing an overall change.

[0061]In use, the mobile controller is run through the wellbore with a wireline. The mobile controller can remain switched on, and can be pulled past the series of ICDs, switching each one from open to closed when passing by. In this use scenario, the mobile controller does not need to ‘know’ the precise location of the ICDs. If the location does need to be determined, the ICDs can be provided with an RFID tag, and the mobile controller with a corresponding detector circuit, for example, or other locating means can be provided. Alternatively, or in addition, a Casing Collar Locator, CCL, can be used. A CCL as such is a known tool for locating the position of a collar. When the distance from the collar to the ICD is known, the CCL can be used to locate the ICD. A CCL is normally run as a standard depth correlation tool on electric wireline operations, but can also be used for finding exact position of the ICDs.

[0062]The presence and direction of the electrical current can be controlled directly from the wireline, by passing a current through one of the electrical cables of the wireline into the coils. Alternatively, a local microprocessor is provided at the mobile controller for controlling the current, and the microprocessor is arranged to receive signals from the surface through the wireline.

[0063]FIG. 6 illustrates the mobile controller of FIG. 5 when passing a set of inflow control devices (ICDs) 61, provided within a sand screen joint 62. The magnetic field lines pass through the ICDs to switch the position from open to closed, or the other way around. The housing of the ICD and position within the joint 1202 is designed to avoid shielding of the magnetic field from the mobile controller, by positioning and/or selection of magnetic materials. A magnetic field can be blocked by a Faraday cage, or a thick layer of magnetic material, and such structures are avoided between the ICD and the mobile controller. The mobile controller is preferably centered within the wellbore or pipe, and standard centralisers can be used for this purpose.

[0064]FIG. 7 illustrates an inflow device 70 device installed within a screen section. FIG. 7A illustrates the open position, with the arrows indicating the inflow. FIG. 7B illustrates a device in a closed position. A tubing 71 is shown, but only one side of the tubing is shown with the device in place. A screen 73 is attached to the outside of the tubing, and can be a sand screen. A sand screen keeps sand or larger debris out, while letting fluids through. A channel is provided between the sand screen and the tubing to allow fluid flow 74 towards the inlet device. The frusto-conical shape of the top of the housing of the device provides a smooth inflow path.

[0065]A wireline 75 is used to pull measurement tool 76 and mobile controller 77 through the wellbore, and past the inflow control device 70. The measurement tool is used to measure the inflow and composition of well fluids, the measurement result may be sent to a processor to determine a control signal for mobile controller 77. The measurements may also be evaluated by a human operator before deciding the desired state of the ICDs. For example, if an inflow of water is detected, the mobile controller can close the inflow control device. Alternatively, the mobile controller remains on and switches all inflow control devices it passes without detecting inflow or the precise location of the inflow control device. The presence of the inflow control device may also be determined using RFID technology, or using a CCL mentioned previously.

[0066]A possible use scenario is first carrying out a full run of the wireline mobile controller through the complete reservoir to collect data of the functioning of the well system. Subsequently, without pulling the tools out of the well in between, carrying out another run past the ICDs to open or close individual ICDs to optimise production.

[0067]The diameter of the main housing of a small inflow control device can be around 33 mm, and the thickness 14 mm. The inflow opening may be between 2.5 and 9 mm. However, larger and smaller dimensions are possible. A typical size of an autonomous inflow control device is 45 mm deep and 14 mm high.

[0068]As detailed above, landing arrangements are provided between the permanent magnet of the gate and their respective ferromagnetic inserts for improved sealing and avoiding a magnetic force that is too large to overcome. As the landing arrangements spatially separate the permanent magnets from the ferromagnetic inserts they allow fluid to pass over both opposing faces of the gate, when in the closed and open position, such that fluid pressure acts on both opposing faces of the gate. Preferably, but not necessarily, the projected surface area of each opposing face of the gate onto the transverse plane of the inflow control device is substantially equal, such that the net force exerted on the gate, urging the gate between the closed and open position, is substantially zero. For the avoidance of doubt, the surface normal of the transverse plane is collinear with the direction of travel of the gate between the closed and open position. This reduces the force required to switch the position of the gate.

[0069]In some examples, the pressure of fluid acting on each opposing face of the gate may differ (but this is expected only to be by a small amount) and in those examples, the gate is considered to be “near” pressure balanced. The force required to switch the position of the gate is still reduced.

[0070]FIG. 8 illustrates an alternative arrangement for the ICD, whereby the mobile controller sends a short pulse of EM energy towards the ICD. The mobile controller has an EM transmitter for this purpose, arranged to transmit an RF pulse. Examples of transmitters are a loop antenna, a coiled antenna, a dipole antenna. The pulse has a first frequency for opening the ICD, and a second frequency for closing the ICD. Although purely for illustrative purposes, the frequency of the first pulse may be around 300 MHz, and the frequency of the second pulse may be 350 MHz, or higher to avoid overlap with the first resonance. GHz frequencies may also be used, although frequencies within the absorption band of water are preferably avoided. The first frequency is resonant with a first pickup coil located at the ICD, while the second frequency is resonant with a second pickup coil located at the ICD.

[0071]FIG. 8A illustrates a first circuit for picking up the first frequency f₁ comprising an inductor L₁, typically a coil, and a capacitor C₁. The signal is rectified, for example by an ac to dc converter D₁, and the signal is then coupled to a coil L₃ for pushing the magnet M. Likewise, inductor L₂ is arranged to pick up the second frequency f₂ in a circuit with capacitor C₂ and rectifier D₂, to drive second coil La for pulling the magnet M. The pulling and pushing is obtained by generating opposite magnetic fields.

[0072]FIG. 8C illustrates an eICD including the inductors L₁ and L₂ at a lower part of the eICD, such that it is close to a mobile controller when the mobile controller is passing the eICD. The inductors L₃ and L₄ are provided close to the magnet M such that they can apply a force onto the magnet. The eICD is illustrated in open configuration, with the arrows showing a fluid path through the eICD.

[0073]The same inductors L₃ and L₄ can be used in non-contingency operations, when they receive power and signal from cables or other means which are permanent features of the well assembly, instead of receiving a signal or power from the mobile controller.

[0074]Besides the inductors illustrated in FIG. 8C, the ICD has a slightly different layout. The inflow channel is still at the top in the directions illustrated in the figure, but the outflow channel is at the sidewall, at about a third of the distance from the top, instead of at the bottom. This variation can also be used in the inflow devices illustrated before. The ICD is still pressure balanced, because the area of the gate that is exposed to fluid pressure in the open position, closed position, or in between, is substantially the same.

[0075]FIG. 8D illustrates schematically a mobile controller with electronic circuit 81 and an antenna 82 for generating and emitting an RF pulse. The electronic circuit 81 is arranged to receive power and signal from the wireline.

[0076]A variation of the ICD illustrated in FIG. 8C is one where one or more permanent magnets are provided in the housing instead of the gate. The magnets are provided in the gate seat, adjacent to the gate in the open position, and further in the seat adjacent to the gate in the closed position. The gate itself comprises a magnetic material. A magnetic material can be attracted, but not repelled by a magnet, whether a permanent magnet or an electromagnet. The electromagnets are therefore provided on the side of each of the seats, in order to attract the gate to the open position by an electromagnet in the ‘open seat’ and to attract the gate to the closed position by an electromagnet in the ‘closed seat’,

[0077]A wireline tractor may also be attached to the wireline assembly, in particular for moving the assembly upstream into the well when the well has a substantial horizontal portion.

[0078]In all of the described examples, the inflow control device is controlled remotely by the mobile controller without requiring power or signal supply through cables or other means extending to the inflow device. This technical effect circumvents challenges associated with supplying signal and power to the inflow control devices, whether through a cable or through the pipe.

[0079]The same general concepts presented above can be put into effect in a different arrangement, such as the alternative embodiment illustrated in FIG. 9. Many details have been omitted in FIG. 9, as it is intended to show the different overall design of the housing and the gate. The gate 91 has a central opening, extending from the top of the gate straight to the bottom of the gate. The opening aligns with a central opening in the housing 92 in the opened configuration, illustrated in FIG. 9A. A central housing portion 95 is provided, which blocks the central opening of the gate in the closed configuration, illustrated in FIG. 9B. The flow 93 of fluids is illustrated with arrows, going around the central housing portion 95, through the central opening in the gate and finally through the central opening in the housing. In the embodiment where pick-up coils are used to transform EM energy from a pulse, electromagnets are provided, for example in central housing portion 95, and/or the lower part of the housing (not illustrated). In the embodiment where the switching is carried out magnetically, the gate has a permanent magnet, and the housing portions that are in contact with the gate in the open and closed configurations comprise ferromagnetic, or magnetisable, portions, in combination with spacers or a landing arrangement, as described before.

[0080]FIGS. 10A and 10B illustrate another design for the housing and gate. The differences over the design of FIG. 9 are a gate that does not have a central opening, but is an un-interrupted disc or other shape matching the inner bore of the housing. This provides for a simpler gate design. A side outlet 103 is defined by the housing, instead of a central outlet, whereby the side outlet is below the gate in the closed configuration.

[0081]An advantage over existing autonomous control valves is that the opening or closing can be complete, as opposed to the partial opening or closing. When a large water production occurs in a section of the well, for example, it might be preferable to completely close all corresponding inflow control devices to shut out the water.

[0082]FIG. 11 shows a method diagram for controlling inflow of fluids into a well. The method comprises steps of (S1) providing an inflow control device for use in a hydrocarbon producing well, the inflow control device being configured to switch reversibly between an open state and a closed state, or between a closed state and an open state. The inflow control device can be any of the devices described previously herein. There may be an array of many devices distributed throughout the well system. In the subsequent step (S2) a mobile controller is moved through a bore of the well. The mobile controller may be one of the controller described previously, whether providing a magnetic field, or emitting an EM pulse. In the next step (S3), the inflow control device is opened or closed reversibly by the mobile controller. The mobile controller may then be moved on to the next device. The mobile controller may be stationary when opening or closing an inflow control device, or may be kept moving, closing or opening devices while passing.

[0083]Although the invention has been described in terms of preferred embodiments as set forth above, it should be understood that these embodiments are illustrative only and that the claims are not limited to those embodiments. Those skilled in the art will be able to make modifications and alternatives in view of the disclosure, which are contemplated as falling within the scope of the appended claims. Each feature disclosed or illustrated in the present specification may be incorporated in the invention, whether alone or in any appropriate combination with any other feature disclosed or illustrated herein.