A well device for throttle regulation of inflowing fluids

(74) Agent

Reslink AS, PO Box 204,4339 Algård, NO Arthur H Dybevik, 4307 Sandnes, NO

Ove Sigurd Christensen, 4041 Hafrsfjord, NO Terje Moen, 4321 Sandnes, NO

Håmsø Patentbyrå ANS, 4302 Sandnes

<td>(54) Designation</td><td>Flow control device for throttling flowing fluids in a well</td>

<td>(56) Cited publications</td><td>US 5435393, US 5803179, US 5906238, US 6112815</td>

(57) Summary

Flow arrangement (10, 12) for use in a well through one or more underground reservoirs, and wherein the arrangement (10, 12) is adapted to pressurize radially flowing reservoir fluids extracted through an inflow portion of the well production tubes, the production tube in and along this inflow path. may be provided with one or more arrangements (10,12). Such an arrangement (10, 12) is arranged to cause a relatively stable and predictable fluid pressure drop at any stable fluid flow rate during the recovery period of the well, and wherein said fluid pressure drop should be affected to a minimum extent by viscosity differences or and / or any viscosity changes in the fluid flow rate. inflowing reservoir fluids during the recovery period. Such a fluid pressure drop is provided by the arrangement (10, 12) bl. a. may comprise one or more short, detachable and interchangeable flow restrictions, for example, nozzle inserts (44, 62), and wherein the individual flow restriction can be arranged with the desired flow cross-section through which reservoir fluids can flow and pressure-strain, or the flow restriction can be a sealing plug.

iiiii

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FLOW CONTROL DEVICE FOR STRUCTING INFLUENTIAL FLUIDS IN A WELL

Field of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control device for pressurizing fluids which flow radially into a well, preferably a petroleum well, drainage pipe, for recovering said fluids from one or more underground reservoirs. Hereafter, said drainage pipe is referred to as a production pipe.

The flow control device is preferably used in a horizontal or approximately horizontal well, such a well being hereafter referred to as a horizontal well. It is particularly advantageous to use such flow control devices in long horizontal wells. The invention, on the other hand, may equally well be used in non-horizontal wells.

BACKGROUND OF THE INVENTION

The invention is designed to prevent or reduce some problems that may arise in a hydrocarbon reservoir and its horizontal well (s) in recovery-related changes in reservoir fluids. These changes lead, among other things, to to fluctuating production rates and uneven drainage of the reservoir. There are particular problems associated with changes in reservoir fluid viscosity which this invention seeks to remedy.

On the upstream side of a horizontal well, the production tube is disposed in the horizontal or approximately horizontal portion of the well. This portion is hereinafter referred to as simplified as a horizontal portion. During recovery, the reservoir fluids flow radially through the openings or perforations of the production tube. The production tube may also be provided with filters or so-called sand screens that prevent formation particles from flowing into the production tube.

As the reservoir fluids flow through the horizontal portion of the production tube, they are applied to a pressure drop due to. flow friction in the tube. The frictional pressure loss is usually nonlinear and strongly increasing downstream. Accordingly, the flow of pressure in the fluid flow of the production tube is non-linear and greatly decreases in the downstream direction.

However, at the commencement of recovery, the fluid pressure in the outer reservoir rock will often be relatively homogeneous, and the fluid pressure will change slightly along the horizontal portion of the well. The differential pressure between the fluid pressure in the reservoir rock and the fluid pressure in the production tube will thereby be nonlinear and strongly increasing in the downstream direction. This means that the radial inflow rate per unit length of the horizontal portion of the production tube is substantially greater on the downstream side (at the heel of the well) than on the upstream side (at the toe of the well) of the horizontal portion. Downstream reservoir zones are thereby drained significantly faster than upstream reservoir zones, so that the reservoir is drained unevenly.

In hydrocarbon extraction, and especially in the extraction of crude oil, this ratio can also cause premature water and / or gas to flow into downstream positions of the horizontal portion and mix with the desired fluid in the extraction stream, so-called king of water or gas in the well. This is especially true in wells with large horizontal well lengths, where the horizontal portion can be several thousand meters long and where the frictional pressure loss of the fluids in the horizontal portion is significant. This relationship leads to production technical disadvantages and problems.

Uneven recovery rates from different zones of the reservoir also lead to fluid pressure differences between the reservoir zones. This can lead to so-called cross or cross flow of the reservoir fluids. flows in and along an annulus between the outer surface of the production tube and the hole wall of the well rather than flowing through the production tube.

Due to the above recovery-related conditions and problems, flow control devices can be used to pressurize fluid inflow appropriately along the production tube and so that reservoir fluids have equal, or approximately equal, radial inflow rates per unit length of the well horizontal portion.

Known technique

Patent publications US 5,435,393 and US 6,112,815 disclose flow control devices for pressure throttling of reservoir fluid radial inflow rates in a production tube. These flow control devices may optionally be remotely controlled and arranged for adjustable downhole throttling of the flowing reservoir fluids. Both flow control devices are arranged to cause flow friction, and thus a fluid pressure drop, in the reservoir fluids as they flow through the current flow control device.

US 5,435,393 discloses a production pipe consisting of several pipe sections, each of which is provided with flow control means consisting of at least one inflow channel through which the reservoir fluids flow before they flow into the production pipe. In the inflow channels, the fluids are subjected to flow friction and a resulting fluid pressure loss. Such an inflow channel is arranged in an opening or annulus between the outside and inside of the production tube, for example in a thickening or sleeve outside the production tube. In one embodiment, the reservoir fluids are first passed through a sand filter and then through an inflow channel of said type and further into the well production tubes. According to US 5,435,393, such inflow channels may consist of longitudinal and thin tubes, bores or grooves through which the fluids can flow and be subjected to said flow friction and fluid pressure loss. The fluid pressure loss in each pipe section can be largely controlled by aligning each pipe section with an appropriate number of tubes, bores or grooves having the appropriate geometric design, for example, appropriate flow cross-section and / or length.

US 6,112,815 also discloses a production pipe composed of pipe sections, each of which is provided with flow control devices. Each such device is arranged in an opening or annulus on the outside of the production tube. The flow control device consists of an axially displaceable sleeve formed with a plurality of axially extending and helical grooves in its outer surface. The sleeve grooves are arranged in said opening or annulus and abut an outer, stationary tube sleeve. The sleeve grooves in the slidable sleeve thereby form helical inflow channels through which formation fluids can flow. The displaceable sleeve can be displaced axially by a suitable actuator device, for example a remote controlled hydraulic, electric or pneumatic actuator / motor. Thus, the length of said track / inflow channels can be adjusted or they can be completely shut off. Also in this flow control device, the reservoir fluids are subjected to flow friction, and thereby an associated fluid pressure loss, as they flow through the device. The design of these helical grooves causes a substantially greater degree of turbulence in the fluid flow than the flow controllers of US 5,435,393, whereby the fluid pressure loss of the fluid stream increases substantially.

Disadvantages of the prior art

The above known flow control devices are subject to a number of application restrictions under the well conditions, such as pressure, temperature and fluid composition, present at any time in a producing petroleum well, and which change during the recovery period of the well.

Remote controlled means which are used in conjunction with said flow control devices, and which regulate fluid inflows through them, often comprise fine mechanical and / or electronic components. The components may consist of remote controlled valves.

removable flaps, plates or pistons, actuators and motors. Such technical solutions are often expensive and complicated.

In addition, said means often fail, or they function unsatisfactorily down in the well.

The above flow control devices may also be complicated to manufacture and / or assemble in a pipe. The devices according to US 5,435,393 require, inter alia, use of a comprehensive and expensive machining equipment to be assembled with a production pipe. The devices of US 6,112,81510, on the other hand, should be easier to manufacture and assemble with a production tube, and the pressure thrusters therein should also be more reliable than those of US 5,435,393.

These flow control devices also cause a small predictable pressure drop in the fluid inflows when their viscosity of ice varies greatly during the recovery period. As mentioned, the fluid pressure loss in these flow control devices is based on flow friction in an inlet duct. proportional to the viscosity of the fluid at both laminar and turbulent flow through the duct. Large fluctuations in the viscosity of the reservoir fluids thereby result in large fluctuations in the fluid pressure drop, and thereby in the flow rate, upon flowing through such a flow control device. The production rate of the well thereby becomes unpredictable and difficult to control.

The latter conditions include: in that all naturally occurring reservoirs, and especially hydrocarbon reservoirs, are heterogeneous and exhibit three-dimensional variations in their physical and / or chemical properties, including their porosity, permeability, reservoir pressure, and fluid composition. These properties and natural variations are altered during the recovery of the reservoir fluids.

Especially with the recovery of hydrocarbons, the properties of the flowing reservoir fluids are gradually changed, including their fluid pressure and fluid composition. The fluids recovered can thereby consist of both liquid and gas phases, including various liquid types, for example water and oil or mixtures thereof. Because of. differences in these fluid weights, the fluids are usually segregated in the hydrocarbon reservoir, which may thereby contain an upper gas layer (a gas cap), a middle oil layer, and a lower water layer (so-called formation water). Additional segregations based on differences in weight may also be present in the individual fluid phases, and especially in the oil phase. Such conditions give rise to large variations in the viscosity of the produced fluids.

Petroleum recovery also leads to displacement of the boundaries between said fluid layers in the reservoir. In case of large capillary effects in the reservoir rocks pores, the fluid bed boundaries may also exist as transition zones in the reservoir. The transition zones will also move in the reservoir during recovery. Such a transition zone contains a mixture of fluids from each side of the zone, for example a mixture of oil and water. As the transition zone moves in the reservoir, the fluid distribution of the fluids, for example the oil / water ratio, also changes in the reservoir zones or positions affected by the fluid movements. Moving fluid bed boundaries or fluid bed transition zones in the reservoir can also lead to large variations in the viscosity of the produced fluids.

However, although the viscosity of the reservoir fluids may vary widely during the recovery period, the same reservoir fluid self-weight values ​​will usually vary little during the recovery period. This is especially true of the liquid phases of the reservoir.

As an example of this, the formation water of an oil reservoir can have a viscosity of approx. 1 centipoise (cP), and its crude oil can have a viscosity of approx. 10 cP. A mixture of 50 volume percent formation water and 50 volume crude oil, on the other hand, may have a viscosity of approx. 50 cp or more. This is usually a result of viscous emulsions being formed by mixing oil and water. The viscosity of such an oil / water mixture is often significantly higher than the viscosity of the individual liquid components of the mixture. However, the formation reservoir of the oil reservoir may, however, have a specific gravity of 1.03 (kg / dm³), and said crude oil may have a specific gravity of the order of 0.75-1.00 (kg / dm³). The mixture of formation water and crude oil will therefore have a specific gravity of the order of 0.75-1.03 (kg / dm³), which differs little in relation to the intrinsic weight of the individual liquid components of the mixture.

The object of the invention

The primary object of the invention is to provide a flow control device which reduces or eliminates the above-mentioned drawbacks and problems of known flow control devices.

This is especially true of the recovery-related disadvantages and problems that arise from the extraction of hydrocarbons via horizontal wells. is associated with fluctuations in the viscosity of flowing reservoir fluids during recovery.

It is a further object to provide a flow control device which, although the viscosity of the reservoir fluids varies during the recovery period of the well, causes a relatively stable and predictable pressure drop in the fluids flowing into the well production tube via the flow control device. Thereby, the flow rate of the fluids through it will also be relatively stable and predictable.

How the purpose is achieved

The object of the invention is achieved by features as set forth in the following description and in the following claims.

By applying at least one flow control device of the present type along the inflow portion of the production tube, a suitable pressure throttling of at least partial flows of the inflowing reservoir fluids can be made. Thus, reservoir fluids from different reservoir zones may flow into the well with equal, or approximately equal, radial inflow rate per unit length of the inflow portion, and even if the fluid viscosity changes during the recovery period. In use, one or more positions along the inflow portion of the production tube are provided with a flow control device according to the invention. By using several similar flow control devices, each flow control device is conveniently spaced from other flow control devices in the production tube.

Such a flow control device comprises a flow channel through which reservoir fluids can flow. The flow channel 20 consists of an annular cavity formed between an outer housing and a base tube and an inlet at the upstream end of said cavity. The outer housing is arranged as an impermeable wall, for example as a longitudinal sleeve of circular cross-section, while said base tube constitutes a main component of a pipe length in the production pipe. At its downstream end, the flow channel comprises at least one through-wall opening in the base pipe. The flow duct thereby connects the inner course of the base tube with surrounding reservoir rocks. The upstream end of the flow channel may optionally be connected to at least one continuous open sand screen which connects the flow channel to the reservoir rocks and which prevents formation particles from flowing into the production tube. At least one through-going channel opening is provided in the flow channel which is provided with a flow restriction. The flow restriction may be disposed in said wall opening in the base pipe, or it may be disposed in a duct opening in an annular collar portion of the outer housing. The collar portion protrudes into the cavity between the housing and the base tube.

It is peculiar to the invention that each such channel opening is provided with a flow restriction selected from the following types of flow restrictions:

- a nozzle;

- an aperture in the form of a slit or a hole; or

- a sealing plug.

In fluid flow through a nozzle or blend, ice pressure energy is converted to velocity energy. A nozzle or diaphragm is a structural element designed to avoid or minimize the loss of energy in flowing fluids. The nozzle or aperture thereby acts as a speed gain element. The fluids thereby discharge at high velocity and collide with fluids which flow more slowly on the downstream side of the velocity increase element. Such continuous fluid collisions are converted into a permanent energy loss in the form of heat.

This energy loss reduces the compressive energy of the flowing fluids, whereby the fluids are applied to a permanent pressure loss which reduces their flow rate in the production pipe. The loss of energy thus occurs downstream of the nozzle or aperture. In the flow control devices according to US 5,435,393 and US 6,112,815, on the other hand, the energy loss arises as flow friction in channels in the devices. The energy loss caused by the present flow control device thus acts according to a different rheological principle than the flow principle used in the known flow control devices. The effects of the two rheological principles in a flow control device, on the other hand, can have a great influence on the pressure throttling of the individual partial flow flowing through it, and thereby on the production profile of the well during the recovery period.

The energy loss caused by fluid flow through nozzles and blenders is little affected by changes in the viscosity of the fluids. of changes in fluid self-weight. This relationship can be utilized with great advantage in connection with hydrocarbon recovery, and especially in the extraction of crude oil and related liquids. As mentioned, in petroleum reservoirs, the viscosity values ​​of the reservoir fluids are usually changed most during recovery, while the fluid weight values ​​of the fluids change little. Under such conditions, the present flow control device could effect a relatively stable and predictable fluid inflow rate during the recovery period of the well. This differs substantially from the aforementioned known flow control devices which, under similar reservoir conditions, will cause an unstable and unpredictable fluid flow rate therethrough.

In addition, pressure throttling via flow control devices along the inflow portion must be adapted to the prevailing conditions at the individual device inflow position in the reservoir. Such conditions include: well recovery rate, fluid pressure and fluid composition in and along the production tube and in the reservoir rock outside it. These conditions also include the relative position of the flow control device relative to the position of other flow control devices along the production tube, as well as the strength, porosity and permeability of the reservoir rock at the current inflow position.

The energy loss resulting from fluid collision on the downstream side of the flow restriction (nozzle or diaphragm) can be measured as a pressure difference in the dynamic pressure of the fluid in the flow restriction (position 1) and in a flow position immediately downstream of the fluid's collision zone (position 2).

The fluid's dynamic pressure 'p' derived from Bernoulli's equation is:

p =% (p 'v²); where ίο 'p' is the fluid weight; and 'v' is the flow rate of the fluid.

Said energy loss can thus be expressed as the difference between the fluid's dynamic pressure in the upstream position 1 and in the downstream position 2. The fluid pressure loss' Δρι_₂'ice is thus expressed as follows:

Δρι-2 p '(v? - v₂²); wherein 'p' is the intrinsic weight of the fluid;

is the fluid flow rate at position 1; and V₂'is the fluid flow rate at position 2.

It follows that the fluid's dynamic pressure drop 'Δρι_₂are affected by changes in the fluid's own weight and / or by changes in the flow rate of the fluid. As mentioned, the reservoir fluids own weight values ​​change little during recovery and thus have little effect on the energy loss of the fluids caused by the existing flow control device. This will affect 'Δρι_₂mainly due to changes in the velocity of the fluid upon flow through said flow restriction. However, the fluid flow rate in the nozzle or aperture can be controlled by e.g. to select an appropriate flow cross section in it. This flow cross-section can optionally be distributed over several such restrictions in the flow control device, and the total flow cross-section of the device may be equal or evenly distributed between the flow restrictions in the device.

By using multiple flow control devices along the inflow portion, each device can be provided with an overall flow cross section which is individually adapted, causing the desired energy loss, and thereby the desired inflow rate, in the subflow flowing in through the flow control device. Thereby one can also suitably adjust and reduce the differential pressure which drives the fluids into the production tube from the surrounding reservoir rock. This is particularly useful in horizontal wells, where said differential pressure is usually greatly increased in the downstream direction of the inflow portion and where the need to pressurize the reservoir fluid inflow rate increases strongly in the downstream direction of the inflow portion. Under such conditions, therefore, downstream portions of the production tube may be provided with an appropriate number of flow control devices of the present type, each device in the position of use being positioned at an appropriate position along the inflow portion and providing an appropriate pressure throttling of the fluids. In upstream portions of the production pipe, however, reservoir fluids may flow directly into the production pipe through openings or perforations therein, possibly via one or more upstream sand screens.

In addition, individual or group flow control devices may be associated with different production zones of the reservoir (s) that the well penetrates. For production purposes, the different production zones may be separated by pressure and flow insulating gaskets of known type.

Before a well is completed, additional information is often obtained regarding the production properties of the reservoir rocks and the composition, pressure, temperature and the like of the reservoir fluids. In addition, information is available on the desired recovery rate and recovery method (s), reservoir heterogeneity, length of the well inflow portion, calculated flow pressure loss in the production pipe, etc. On the basis of such information, it is possible to estimate, both physically and temporally, a probable flow and pressure flow (flow and pressure profile) for the inflowing reservoir fluids. Thereby one can also estimate and determine the specific need for flow control devices in the current well. This includes determination of the number, relative location and location density, as well as individual design of the flow control devices. Such decisions and individual adjustments must often be made within a very short period of time. On the other hand, in order to be able to adapt the production pipe's inflow portion in a short time with a suitable pressure throttling profile, simple, effective and flexible means must be available to carry this out. This adaptation work should preferably be performed immediately before the production pipe is installed in the well. The adaptation work assumes that each flow control device in the production pipe can be quickly and easily aligned with a pressure throttling degree adapted to a specific recovery rate as well as the well conditions prevailing in each device's intended position in the well.

This problem can be solved in that the at least one flow restriction in the flow control device is designed as a loose bar, and thus interchangeable, insert. The insert, which may be a nozzle, a diaphragm or a sealing plug, is placed in said through opening in the flow channel of the device, the opening being hereafter referred to as an insert opening. The insert and the associated insert opening are complementary in design. An insert opening may consist of a bore or punch through said base tube or through said annular collar portion in the flow channel of the device. In addition, the insert may, for example, but not necessarily, have an external circular cross-section. The collar portion may consist of a circular steel ring or steel collar disposed in the outer housing of the device. The insert can be removably fastened in its insert opening by means of known fasteners and fasteners, for example by means of threaded connections, fasteners, including saw rings, ice fastening plates, locking sleeves or locking screws.

A flow channel provided with more than one insert opening may also be provided with inserts arranged with different types of flow restrictions of said types. The flow channel can thereby be provided with any combination of nozzles, blenders and sealing plugs. In addition, nozzles and / or blenders in the flow channel may be arranged with different internal flow cross-sections. Thus, e.g. nozzles in the flow channel have different internal nozzle diameters, the individual flow cross-sections of the nozzles together constituting the flow cross-section of the flow control device, and where the total flow cross-section causes the desired fluid pressure loss in the device. In addition, sealing plugs can be used to seal inlet openings through which fluid flow is not desired. Accordingly, based on the total flow cross section, each flow control device in the production tube can be arranged with an individually adapted pressure throttling degree so that the reservoir fluids get equal, or approximately equal, radial inflow rate per unit length of the well inflow portion.

A flow control device whose nozzle inserts are arranged in through openings in the pipe wall of the production pipe may also be provided with one or more nozzle pairs. Nozzle inserts in a nozzle pair should preferably be arranged diametrically opposed to each other in the pipe wall, so that their outgoing fluid jets are directed towards each other and collide in the inside of the production pipe. This prevents or reduces erosion of the inner surface of the production pipe.

When using several detachable and interchangeable inserts in a flow control device, both the inserts and the insert openings should be of the same size and shape, for example inserts and associated bores of equal diameter. When using multiple flow control devices in the production tube, all inserts and insert openings in the production tube should be of the same size and shape.

In addition, insert openings in such a flow control device should be readily available, so that insertions in the insert openings can be quickly and easily replaced, if necessary. According to the invention, this availability can be achieved by the external housing of the flow control device being arranged in such a way as to provide temporary access to said insert openings. For example, the exterior housing may be provided with at least one through-access opening, for example a bore, which is located immediately outside a corresponding insert opening in the wall of the base tube. For this purpose, the housing may be enclosed by a removable cover sleeve or cover plate which covers the at least one access opening and which can be quickly and easily removed from the housing. Thus, the at least one insertion opening can easily be uncovered for temporary access to it. When the insert opening (s) is disposed in said annular collar portion of the outer housing, the housing may comprise an annulus housing which is detachably enclosing the collar portion. By removing the annulus housing from the collar portion, temporary access to the collar portion insert (s) is created. In this way, an insert can be quickly and easily placed or replaced in an insert opening in the collar portion.

By using such detachable and interchangeable inserts, the production pipe can be optimally adapted to the relevant well and reservoir information available immediately prior to its entry into the well. In this connection, one or more insert openings in a flow control device can be provided with a sealing plug which prevents fluid flow. This is due in part to the fact that before the commissioning of the production pipe, and before the well and reservoir information is available, it can be difficult to determine the exact number, relative position and individual design of the production pipe flow control devices. It may therefore be appropriate and

2o saving time a certain number of individual pipe lengths of the production pipe with flow control devices of a standardized design, and with a certain number of empty size openings of openings. After updated well and reservoir information is available, each flow control device in the production tube can be aligned with individually tailored pressure throttling. Each device is provided with flow restrictions selected from the above types of restrictions and selected in the desired number, size and / or combination thereof. For example, if one wishes to stop inflow through such a standardized flow control device, all of the insert openings therein may be provided with sealing plugs.

Brief mention of the drawing figures

The following part of the description shows two non-limiting exemplary embodiments and associated figures of a flow control device according to the invention. One particular reference number refers to the same detail in all figures where the detail is indicated, where:

Fig. 1 shows a partial section through a pipe length of a production pipe, the pipe length being provided with a flow control device which ia. comprises nozzle inserts arranged in radial insert bores in the wall of the pipe, the figure also showing section lines VV and VI-VI;

FIG. 2 is an enlarged sectional view of the flow control device of FIG. 1, FIG. 2 also showing section line VV;

Figure 3 also shows a partial section through a pipe length provided with a flow control device which, in contrast, comprises nozzle inserts arranged in axial insert bores in a collar portion of a tubular housing around the pipe length, the figure also showing section lines VV and VI-VI;

Fig. 4 shows an enlarged circular section of details of the flow control device of Fig. 3, Fig. 4 also showing section line VV;

Fig. 5 shows a radial partial section along the section line VV according to Fig. 1 and Fig. 3, where the section shows a connection sleeve between the flow control device and a sand screen,

Fig. 5 also shows section line II; and where

Fig. 6 shows a partial section along the section line VI-VI according to

Fig. 1 and Fig. 3, where the partial section shows details of said sand screen, the section line II is also shown in this figure.

Description of two embodiments of the invention

Fig. 1 and Fig. 2 show a first embodiment of a flow control device 10 according to the invention, while Fig. 3 and Fig. 4 show a second embodiment of a flow control device 12 according to the invention. Fig. 5 and Fig. 6 show constructive features common to both embodiments.

Both flow control devices 10, 12 are assigned a pipe length 14 which is connected to other pipe lengths 14, not shown, which together constitute a production pipe in a well. The pipe length 14 consists of a base pipe 16 which is threaded at each end and can be connected to other pipe lengths 14 via a pipe 15 coupling 18. In these embodiments, the base pipe 16 is provided with a sand screen 20 located upstream of the flow control device 10, 12. In its one end portion, the sand screen 20 is secured to the base tube 16 by means of an inner end sleeve 22, which is provided with an inner packing ring 23,

2o and by means of an enclosing and outer end sleeve 24. In the other end portion, by the flow control device 10, 12, the sand screen 20 and a connecting sleeve 26 are fixedly connected to each other by means of an outer end sleeve 28. The sand screen 20 is provided with several spacers 30 which is fixed at an inclined equidistant angular distance about the base tube 16 and which runs in the axial direction of the tube 16, cf. Fig. 6. Outside the spacers 30, continuous and tightly wound wire coils 32 are wound so that reservoir fluids can flow through small gap openings between the wire coils

32. Between the winding windings 32 and the tube 16 and the spacers there are thus several axial flow channels 34 through which the reservoir fluids can flow up to and through the connecting sleeve 26. Also the connecting sleeve 26 is formed with axial but semi-circular flow channels 36 distributed equidistantly around the connecting sleeve 26. 5. Through these channels 36, the fluids can flow further into the flow control device 10, 12. Furthermore, it is pointed out that each axial flow channel 34, 36 is designed with a relatively large flow cross-section, so that the flow friction and fluid pressure loss therethrough is minimal relative to the downstream energy loss caused by flow restrictions in the flow control device 10,

12.

In the first embodiment of the invention, cf. Fig. 1 and Fig. 2, the reservoir fluids continue to flow into an annulus 38 in the flow control device 10. The annulus 38 consists of the cavity formed between the base tube 16 and a circular cross-sectional and tubular housing 40 . The housing 40 of its upstream end portion encloses the connector sleeve 26. The housing 40 of its downstream end portion encloses the tube 16 and is provided with an inner packing ring 41. A portion of the pipe 16 in direct contact with the annulus 38 is provided with several through and threaded insert bores 42 of one's bore diameter. A similar number of externally threaded and through open nozzle inserts 44 are releasably disposed in the insert bores 42. All nozzle inserts 44 may have the same internal nozzle diameter or they may have different nozzle diameters. All fluids flowing in through the sand screen 20 will be directed to and through the nozzle inserts 44, after which the fluids are subjected to an energy loss and associated pressure loss. Thereafter, the fluids flow into the base tube 16 and further into its internal bore 46. If fluid flow is not desired through one or more insert bores 42 of the flow control device 10, the relevant insert bores 42 may be provided with a threaded sealing plug insert not shown. In order to be able to quickly insert or replace nozzle inserts 44 and / or seal plug inserts in said insert bores 42, the housing 40 is provided with through-access bores 48 corresponding in number and position with the insert bores 42. Through the access bores 48, and by means of a suitable tool, one can inserting or removing nozzle inserts 44 and / or sealing plug inserts. In this embodiment, the access bores 48 are shown sealed from their outer surroundings by means of a cover sleeve 50 which is detachably mounted, and preferably pressure-sealed, on the tubular housing 40 by means of a threaded connection 51. Subsequently, the pipe length 14 can be connected to other tubes 14 to a tubing.

In the second embodiment of the invention, cf. Fig. 3 and Fig. 4, the reservoir fluids flow from said connecting sleeve 26 and downstream further into a first annulus 52 of the flow control device 12. The annulus 52 consists of the cavity formed between the base tube 16 and a surrounding and tubular housing 54 of circular cross section, the annular space 52 being an integral part of housing 54. Housing upstream of its housing 54 upstream of the connector sleeve 26. The downstream end portion of the housing 54 is formed as an annular collar portion 56 enclosing the tube 16 and projecting into said cavity, the collar portion 56 of this embodiment being provided with an inner packing ring 58. Along its circumference, the collar portion 56 is further provided with axially continuous and threaded insert bores 60 of one's bore diameter. A similar number of threaded and through open nozzle inserts 62 is releasably disposed in the insert bores 60. Similar to the flow control device 10, nozzle inserts 62 of different internal nozzle diameters can be placed in the insert bores.

60. One or more insert bores 60 may also be provided with separate and threaded sealing plug inserts not shown. Inside, the collar portion 56 is provided with extension bores 64 which connect the insert bores 60 to the annular space 52. Immediately outside of the insert bores 60, the collar portion 56 is additionally formed with an outer circumferential portion 66 recessed relative to the remaining portion of the collar portion 56. An upstream end portion of an annular housing 68 is disposed detachably, and preferably pressure-sealing, about said circumferential portion 66, while the annular housing 68 its downstream end portion encloses the tube 16. In this embodiment, the annular housing 68 its downstream end portion is provided with an inner gasket ring 70 and an inner gasket ring 70. the annulus housing 68 thus forms a second annulus 72. Reservoir fluids flow through the nozzle inserts 62 and into the second annulus 72. Then, through multiple axial slots 74 in the tube 16 and further through the base tube 16, they flow through their internal bore 46. Also in this embodiment, the reservoir fluids are subjected to an energy loss and associated pressure loss on the downstream side of the nozzle inserts 62. Otherwise, the annular housing 68 can be loosened and temporarily removed. from the circumferential portion 66 by means of a threaded connection 76. Thereby, access roads are created up to the insert bores 60, so that nozzle inserts 62 and / or sealing plug inserts can be inserted or removed.