Flow control device and method

Abstract

The present application provides a fluid flow control device (100) for establishing controllable fluid communication between an external fluid reservoir and a base pipe (102) forming part of a production string, a production string and a method of using the fluid flow control device. The fluid flow control device comprises a top housing (19) covering a main flow path inlet (1) of a main housing (8). Fluid flow from the external fluid reservoir flows into the top housing, where it is caused to swirl.

Description

Technical Field

[0001] This invention relates to the control of fluids flowing into a pipeline. More specifically, this invention relates to a fluid flow control device, a subsea production tubing, and a method of using such a fluid flow control device. This invention is useful in controlling the flow of fluids from underground oil and gas (hydrocarbon) reservoirs into a production tubing, and is particularly useful in the autonomous handling of multiphase fluids during production. Background Technology

[0002] Wells used to produce oil and gas from underground reservoirs can extend through the reservoir in multiple orientations. Traditionally, entry into the reservoir is achieved by drilling vertical wells. This is a simple and straightforward technique; however, it provides limited reservoir contact for each well. Therefore, to access more reservoir material in each well, techniques and apparatus for drilling horizontal wells have been developed, i.e., turning the well from vertical to horizontal at a predetermined depth below the surface. These so-called multi-sideways wells offer even greater access to and contact with the reservoir.

[0003] The main challenge in producing oil and gas from underground reservoirs is increasing the capacity to extract oil from those reservoirs. Currently, only a fraction of the oil in a given reservoir is actually extracted and produced before the field is closed. Therefore, there is a strong incentive to develop new technologies to increase production and oil extraction.

[0004] To increase production and recovery from reservoirs, two factors are particularly important:

[0005] To achieve maximum reservoir contact, and

[0006] To prevent the negative effects of natural gas and / or water permeation / penetration (often referred to as "coning").

[0007] Reservoir contact is typically achieved by drilling multiple horizontal and / or lateral wells. The negative effects of coning are usually mitigated by so-called inflow control devices (ICDs) placed within the production string wall. Typically, the production string in a horizontal well comprises a large number of ICDs arranged at regular intervals along its entire length. The ICD serves as an inflow port for oil flowing from the reservoir (usually via the annular space between the production string and the well structure) into the production string and is a port with a fixed flow area.

[0008] A so-called autonomous ICD (AICD) comprises one or more valve elements that are normally open when oil flows through the unit, but block the flow when water and / or natural gas enter the unit, and at the points where water and / or natural gas enter the unit. The annular space between the production tubing and the shell / reservoir is typically divided into multiple zones by an annular packer, as is known in the art. One or more ICDs or AICDs are then placed in each zone.

[0009] Many ICDs are known in the art. The following patents are available: US 5,435,393 (Brekke et al.), US 7,857,050 B2 (Zazovsky et al.), US 7,823,645 B2 (Henriksen et al.), US 2008 / 0041580 A1 (Freyer et al.), WO 2008 / 004875 A1 (Aakre et al.), US 2011 / 0067878 A1 (Aadnoy), US 2008 / 0041582 A1 (Saetre et al.), US 2011 / 0198097 A1 (Moen), US 2011 / 0308806 A9 (Dykstra et al.), US 7,918,275B2 (Baker Hughes Inc.), US 2009 / 0283275 A1 (Baker Hughes Inc.), and US 7,819,196. Find relevant instances of ICD or AICD in B2 (Norsk Hydro ASA).

[0010] The aforementioned patent disclosure has one or more of the following disadvantages:

[0011] - Production can also be blocked by oil, which can lead to significant production losses (barrels / day) during the initial phase of a well's life.

[0012] - At the moment of its breakthrough, the undesirable phase (natural gas / water) is neither blocked nor shut off.

[0013] - An undesirable phase (natural gas / water) is partially blocked, stopping the inflow even though it is not full or nearly full.

[0014] - It does not exhibit reversible properties, that is, the ability to automatically reopen a valve that was closed due to the entry of an undesirable phase when oil begins to flow into the well again.

[0015] - The challenge of controlling opening / closing.

[0016] - High flow resistance within the main flow during the desired phase throughput.

[0017] - Unable to manage harsh well conditions (high pressure and high temperature, scaling, etc.) in a satisfactory manner.

[0018] AICD that overcomes all the above-mentioned disadvantages is disclosed in patent publications WO 2013 / 139601 A2 and WO 2019 / 175078 A1 (Inflow Control), the contents of which are incorporated herein by reference.

[0019] Both existing AICD technologies include a main flow path and a secondary flow path, wherein the secondary flow path further includes two fluid flow restrictors that serve as inflow and outflow ports for the chamber, respectively. These two flow restrictors are configured to produce different fluid flow characteristics.

[0020] In the prior art AICD of WO 2013 / 139601 A2, the secondary flow path is arranged to be in fluid communication with the main flow path, while in the prior art AICD of WO 2019 / 175078A1, the two flow paths are radially separated.

[0021] However, the AICDs disclosed in WO 2013 / 139601 A2 and WO 2019 / 175078 A1 have some drawbacks. During multiphase flow, there is often a mixture of undesirable fluids such as natural gas and water with desired fluids such as oil. Without any additional measures, there is a risk that the aforementioned prior art AICDs will shut down in the later stages of such multiphase flow, leading to the undesirable generation of the undesirable fluids.

[0022] The purpose of this invention is to overcome the shortcomings of the prior art and obtain further advantages. Summary of the Invention

[0023] The invention is set forth and characterized in the main claim, while the dependent claims describe other features of the invention.

[0024] In one aspect of the invention, a fluid flow control device is provided, which is adapted to establish a controllable fluid communication of fluid flow F between an external fluid reservoir and a base pipe that forms part of a production string.

[0025] The fluid flow control device includes a main flow path, movable valve elements, a top housing, and a secondary flow path. The main flow path and movable valve elements are arranged inside the main housing.

[0026] The main flow path includes a main flow path inlet and a main flow path outlet. The main flow path inlet is configured to guide the main fluid flow F0 into the main housing during operation, preferably axially or nearly axially. The main flow path outlet is configured to guide the main fluid flow F0 from the main housing into the base pipe during operation.

[0027] The secondary flow path includes a secondary flow path inlet configured to guide the secondary fluid flow f through the secondary flow path. During operation, the secondary flow path establishes fluid communication between the fluid flow inlet (preferably the main fluid flow inlet) and the base pipe, and includes a first fluid flow restrictor configured to generate a pressure drop from a pressure p1 upstream of the first fluid flow restrictor to a pressure p2 downstream of the first fluid flow restrictor. The secondary flow path also includes a second fluid flow restrictor and a chamber B. The second fluid flow restrictor is disposed downstream of the first fluid flow restrictor and configured to generate a pressure drop from a pressure p2 upstream of the second fluid flow restrictor to a pressure p3 downstream of the second fluid flow restrictor. Chamber B is disposed between the fluid flow restrictors, downstream of the first fluid flow restrictor and upstream of the second fluid flow restrictor. It should be noted that the second fluid flow restrictor can also serve as a secondary flow path outlet in the form of an orifice-shaped control device. In this case, pressure p3 is the pressure in the base pipe during operation. Alternatively, the second fluid flow restrictor and the secondary flow path outlet can be separate structures within the main housing.

[0028] The movable valve element inside the main housing is configured to close the main flow path for fluid flow F, or at least significantly block fluid flow F, when exposed to pressure exceeding a threshold pressure from chamber B.

[0029] The top shell at least covers the main flow path inlet of the main shell and includes a fluid flow inlet that allows fluid flow F (main fluid flow F0 + secondary fluid flow f) to flow from the external fluid reservoir and at least partially enter the main flow path inlet, the aforementioned secondary flow path inlet, and a vortex guide that causes vortex / rotation of fluid flow F between the fluid flow inlet and the main flow path inlet.

[0030] The vortex guide can preferably induce a vortex / rotation of the fluid flow F around and / or upstream of the inlet of the main flow path.

[0031] It should be noted that "cover" here should be interpreted as a top shell arranged above or on the main shell, wherein the radial cross-sectional area of ​​the top shell extends at least the radial cross-sectional area of ​​the main flow path inlet. Furthermore, this specific configuration of the top shell and the main shell must allow fluid flow F to enter both the main flow path inlet and the secondary flow path inlet.

[0032] More preferably, the vortex guide is configured such that the axis of rotation of the vortex is centered in the main flow path inlet and oriented along the direction of movement of the valve element. The portion of the fluid flow F entering the main flow path inlet is reduced to Ff.

[0033] The vortex guide can be positioned between the fluid inlet and the main fluid inlet.

[0034] The secondary fluid inlet can be located at an axial height above the main fluid inlet. The axial and radial directions are defined in this paper as directions perpendicular to and parallel to the longitudinal direction of the base pipe, respectively.

[0035] If the fluid flow F comprises a mixture of two or more phases with different fluid densities (e.g., natural gas and oil), the vortices created between the fluid flow inlet and the main / secondary flow path inlet due to centrifugal force force the lower density phase (e.g., natural gas) to separate from the higher density phase (e.g., oil). By appropriately designing the top shell relative to the main shell—including positioning and determining the dimensions of the fluid flow inlet, the main flow path inlet, and the secondary flow path inlet—it is possible to ensure that a significant portion, such as all or almost all, of the separated lower density phase fluid (e.g., natural gas) is directed into the secondary flow path inlet and further through the flow restrictor.

[0036] For natural gas / oil mixtures, the above configuration therefore favors the entry of the lower-density phase fluid (i.e., natural gas) into the secondary flow path rather than the higher-density phase fluid (i.e., oil). This results in a higher pressure increase in chamber B during the early stages of this multiphase infiltration, which again leads to the desired early shut-off or blockage of the main fluid flow, thereby minimizing the generation of the lower-density phase fluid (natural gas).

[0037] For oil / water flows, the above configuration again favors the entry of the lower-density phase fluid (i.e., oil) into the secondary flow path rather than the higher-density phase fluid (i.e., water). However, in contrast to the case of gas / oil mixtures, oil / water flows result in lower pressures in chamber B during the early stages of multiphase infiltration. This again leads to the desired later closure or blockage of the main fluid flow, allowing the main fluid path to remain open for the production of oil / water mixtures at higher water content.

[0038] Therefore, if the water carries oil, the main flow path remains open for a longer period, and if the water does not carry oil or carries very little oil, the main flow path begins to become blocked.

[0039] In reservoirs containing large amounts of water, any residual oil cannot be effectively separated from the water due to the low density difference. Therefore, water flowing towards the production well in the reservoir typically carries oil droplets due to relatively low buoyancy and relatively high total drag.

[0040] This is not the case for natural gas / oil flows with a significantly higher density difference than water / oil mixtures. Therefore, buoyancy is higher and drag is correspondingly lower. When natural gas and oil flow into the base pipe, the primary driving mechanism for the oil is gravity. During the process of natural gas penetrating into the base pipe, a gas cone is typically formed. When the gas flow stops, gravity forces the oil through this gas cone and into the base pipe.

[0041] Therefore, unlike water / oil flow, oil flows independently of the natural gas rate when natural gas is blocked or stopped.

[0042] For at least this reason, it is advantageous to ensure that the inlet of the main flow path remains open for an extended period of time in the water / oil flow.

[0043] In a typical scenario, the liquid is thrown against the axial wall inside the top shell and further into the main flow path inlet, while the natural gas seeps into the secondary flow path inlet.

[0044] In the alternative configuration, the secondary flow path inlet can be located downstream of the primary flow path inlet. In this case, all fluid flows F are directed to the primary flow path inlet, after which the fluid flows F are either split into secondary flow paths or further through the primary flow path depending on the phase.

[0045] In an exemplary configuration of the present invention, the top housing further includes at least a portion of a secondary flow path arranged in fluid communication with the inlet of the secondary flow path.

[0046] In another exemplary configuration, the secondary flow path inlet may be located in the portion of the top housing facing the primary flow path inlet.

[0047] In yet another exemplary configuration, the secondary flow path inlet can be configured such that the secondary fluid flow f (which constitutes a small portion of the fluid flow F) flows into the secondary flow path inlet in a direction opposite to that of the primary fluid flow F0 (which constitutes the majority of the fluid flow F) during operation.

[0048] In another exemplary configuration of the invention, the vortex guide includes a plurality of fluid flow deflectors spaced apart from each other to form at least one vortex guiding channel having a deflection angle (α) relative to the radial direction of the fluid flow control device, thereby setting the vortex direction of the fluid flow F. In this configuration, the radial direction is defined as perpendicular to the average direction of the main fluid flow when it enters the main flow path inlet. See also the preceding description of the base tube. Each of these plurality of fluid flow deflectors may have a wedge shape, with its two conical sides (which preferably include axially oriented walls) oriented in the direction of the vortex, i.e., its apex away from the fluid flow inlet.

[0049] In another exemplary configuration of the invention, the top housing is divided into a first radial portion and a second radial portion, wherein the first radial portion includes a fluid inlet and a vortex guide, and the second radial portion includes a secondary flow path inlet and at least a portion of a secondary flow path in fluid communication with the secondary flow path inlet. In this configuration, the second radial portion may further cover at least a portion of the main flow path inlet, more preferably the entire main flow path inlet. Furthermore, the second radial portion may be axially thicker relative to the first radial portion, and at least a portion of the secondary flow path may be oriented radially at an axial height equal to or higher than the axial height of the fluid inlet measured relative to the center point of the inlet. It should be noted that the top housing is defined herein as the main housing as described above. The radial boundary between the first and second radial portions may further include an axial wall having a deflection angle α relative to the radial direction of the fluid flow control device, thereby setting the vortex direction of the fluid flow F. As described for the other configurations above, the radial direction is defined as a direction perpendicular to the average direction of the main fluid flow when entering the main flow path inlet.

[0050] In yet another exemplary configuration of the invention, a large portion (i.e., more than 50%) of the length of the secondary flow path extends to the outside of the main housing.

[0051] In a second aspect, the present invention relates to a production string for transporting oil and gas. The production string includes a base pipe, a casing disposed on the outer wall of the base pipe and having at least one casing inlet opening, and a fluid flow control device as described above. The fluid flow control device is disposed in a through-hole in the wall of the base pipe within the casing, thereby providing controllable fluid communication between the interior of the casing and the base pipe. The casing is configured to provide an inlet chamber covering at least one casing inlet opening of the casing and a fluid inlet for the fluid flow control device.

[0052] In a third aspect, the present invention relates to a method for controlling fluid flow F based on changes in fluid properties using the fluid flow control device described above.

[0053] When the fluid flow control device is in the open position, the method includes the following steps:

[0054] -Guide the fluid flow F into the fluid inlet.

[0055] - The fluid flow is guided by a vortex guide arranged between the fluid flow inlet and the main flow path inlet to generate a vortex of fluid flow F around the main flow path inlet.

[0056] -While the fluid flow F is swirling, the main fluid flow F0, which constitutes most of the fluid flow F, is guided through the main flow path inlet within the fluid control device housing; and

[0057] -Guides the secondary fluid flow f through the secondary flow path, and the secondary fluid flow f constitutes a small part of the fluid flow F.

[0058] This can be achieved by making the inlet opening of the secondary flow path smaller than the inlet opening of the main flow path, thus allowing most of the fluid flow through the main flow path inlet and a small portion of the fluid flow through the secondary flow path. Attached Figure Description

[0059] Referring to the accompanying simplified cross-sectional diagrams and figures, these and other features of the invention will become clear from the following description of embodiments given as non-limiting examples, wherein:

[0060] Figure 1 illustrates the principle behind the invention;

[0061] Figure 2 shows the correlation between pressure changes and fluid viscosity changes inside the chamber (i.e., between the fluid flow restrictors);

[0062] Figures 3A and 3B schematically illustrate two different embodiments of the invention, wherein Figure 3A has a single fluid flow output and Figure 3B has two fluid flow outputs; one for the main fluid flow F0 and the other for the secondary fluid flow f.

[0063] Figure 4 A flow control device according to the invention, installed in a production tubing, is shown.

[0064] Figure 5 The flow control device of the present invention is shown, illustrating the length of the coil used as a fluid flow restrictor relative to the size of the main housing of the flow control device;

[0065] Figure 6 Showing more details Figure 5 The main housing of the flow control device;

[0066] Figure 7 The flow control device of the present invention is shown in an exploded view;

[0067] Figure 8A and Figure 8B Cross-sectional views of the flow control device of the present invention are shown in two different perspective views;

[0068] Figure 9A and Figure 9B The top housing of the flow control device of the present invention is shown, wherein Figure 9A A flow control device with a detached top housing is shown. Figure 9B A cross-section of the flow control device is shown, taken along a radial plane passing through the top housing;

[0069] Figure 10A cross-section of the flow control device of the present invention is shown, indicating the directional flow, pressure, force, and area of ​​influence involved during operation. Detailed Implementation

[0070] Figure 1 illustrates how fluids F and f flow into pipe 2 through the main fluid inlet 1 at a first pressure p1, further pass through the first fluid flow restrictor 3, and enter chamber B. At chamber B, the fluid reaches a second pressure p2, and then flows through the second fluid flow restrictor 4 before exiting pipe 2 through the fluid flow outlet 5 at a third pressure p3. When the fluid velocity and fluid properties (e.g., viscosity, density) remain constant, the pressures p1, p2, and p3 are also constant, and p1 > p2 > p3.

[0071] In Figure 1, the first fluid flow restrictor 3 is a coil, and the second fluid flow restrictor 4 is an orifice. The coil can have any cross-sectional shape, such as circular, rectangular, triangular, etc.

[0072] Typically, the pressure loss due to the viscous effect in a cylindrical tube with length L and uniform diameter D is proportional to the length L and can be characterized by the Darcy-Weisbach equation, which is expressed as:

[0073]

[0074] Where: ρ = density of fluid velocity (kg / m³) 3 )

[0075] D L = The hydraulic diameter of the pipe (for a pipe with a circular cross-section, this is equal to the inner diameter of the pipe (m));

[0076] <v>= Average flow velocity, which is the volumetric flow velocity Q (m / s) per unit cross-sectional wetted area, measured experimentally;

[0077] f D = Darcy friction coefficient (also known as flow coefficient λ);

[0078] L = Length of the cylindrical tube (m).

[0079] Therefore, according to the Darcy-Weisbach equation (Equation 1), a large ratio L / D corresponds to a large pressure drop ΔP when fluids F and f flow through pipe 2 (from p1 to p2 in Figure 2).

[0080] In the laminar flow region, Equation 1 can be rewritten as

[0081]

[0082] Therefore, under laminar or near-laminar flow conditions, the pressure change ΔP on the coil can be observed in relation to the fluid viscosity μ and the ratio L / D. 4 Proportional.

[0083] Laminar flow is achieved when the Reynolds number (RE) is less than 4000. Since for fluid flow in a pipe of diameter D, RE = ... <v>·D·ρ / μ, so it can be adjusted by, for example, the diameter D and / or the flow rate. <v>This is to ensure laminar flow. It is clear from Equation 2 that if ΔP is constant, then Q (volume velocity) will decrease with increasing pipe length L, and the result is still velocity. <v>The flow rate decreases. Therefore, a coil with a sufficient length L will form laminar or near-laminar flow.

[0084] The flow characteristics of the fluid flowing through the orifice can be expressed as:

[0085]

[0086] Where: ΔP = fluid pressure difference at the orifice (typical unit: Pa)

[0087] K orifice = Orifice-specific coefficient (dimensionless)

[0088] ρ = fluid density (mass per unit volume)

[0089] v = fluid velocity (a unit of length per unit time)

[0090] Therefore, when flowing through orifice 4, the fluid experiences a pressure drop ΔP (from p2 to p3) described by Equation 3. The change in fluid pressure at orifice 4 is almost independent of viscosity, but is proportional to density, orifice coefficient, and the square of fluid velocity.

[0091] Therefore, referring to Figure 1, if the properties of the fluid (viscosity or density) change, the fluid pressure p2 in chamber B (i.e., between coil 3 and orifice 4) will change. This is graphically illustrated in Figure 2. The first (lower) value of p2 is determined by the high fluid viscosity μ. high The fluid flow is formed, and the second (high) value of p2 is due to the low fluid viscosity μ. low The fluid flow is formed. The difference between the values ​​of p2 that occurs when the fluid properties change (e.g., viscosity decreases), i.e., ΔP2, can be used to do work, such as actuating the actuator 6 (e.g., applying pressure to the actuation surface), which in turn can move the piston 9, which serves as the valve element 9, possibly via hydraulic and / or electrical and / or mechanical transmission 10 (see Figure 3).

[0092] Typically, the present invention utilizes the pressure change ΔP2 that occurs between two different flow restrictors when subjected to fluids of different properties (e.g., oil and water). These properties can be, for example, viscosity, density, or both.

[0093] Figures 3A and 3B are schematic diagrams illustrating two configurations of the above-described principle. Figure 3A shows a first configuration of the flow control device 100 in its basic form (i.e., where seals, gaskets, and other necessary or recommended auxiliary components known in the art are omitted). Fluid flow F enters the main housing 8 via two fluid paths 2 and 7: a main flow path (main conduit) 2 with a main flow path inlet 1 and a secondary flow path (secondary conduit) 7 with a secondary flow path inlet 11. The majority of the fluid flow F, F0 (i.e., greater than 50%), hereinafter referred to as the main fluid flow, flows through the main conduit 2 and the initially opened valve element 9. A smaller portion f of the fluid flow F, such as 5% of the main fluid flow F0, also referred to as the secondary fluid flow f, flows through the secondary conduit 7 before entering the main conduit 2 and exiting via the fluid flow outlet 5. This secondary conduit includes a first fluid flow restrictor 3 in the form of a coiled capillary of length L and diameter D, and a second fluid flow restrictor 4 in the form of an orifice.

[0094] When the viscosity μ of the fluid flow F changes, the second pressure p2 in chamber B between the two flow restrictors 3 and 4 in the secondary pipe 7 also changes. For example, if the flow of oil is replaced by water or natural gas, the viscosity decreases and the second pressure p2 increases, as explained above with reference to Figures 1 and 2.

[0095] Furthermore, Figure 3A schematically illustrates an actuator 6 disposed within or connected to chamber B. Actuator 6 is connected to piston / valve element 9 via a transmission device 10 (e.g., via a hydraulic link, mechanical link, and / or signal cable). Actuator 6 can be any form capable of actuating piston / valve element 9, for example, the surface of valve piston 9 exposed to the force generated by the guide pressure ΔP2, or the surface of movable disc 9 facing chamber B on one side and towards the main flow path inlet on the opposite side.

[0096] When the fluid viscosity μ changes as described above, the difference in the value of p2 (ΔP2, see Figure 1) will apply an actuating force to actuator 6, which in turn operates piston / valve element 9 (e.g., by closing / blocking the main flow path inlet 1). Therefore, pipes 2, 7 and fluid flow restrictors 3, 4 can be configured and sized such that (when preventing penetration) when the viscosity μ of fluid F drops below a predetermined level, piston / valve element 9 automatically shuts off the flow of fluid F. As an example, in oilfield applications, this flow control device 100 prevents unwanted water and / or natural gas from flowing into production string 101 (see Figure 1). Figure 4 ).

[0097] Figure 3B schematically illustrates a second configuration of the flow control device 100. The second configuration is identical to the first configuration, except that the secondary flow path 7 is not in fluid communication with the main flow path 2. Instead, they enter and exit the housing 8 via separate flow paths. The main fluid flow F0 enters the main flow path 2 from the main flow path inlet 1 and exits through the main flow path outlet 5, while the secondary fluid flow f enters the secondary flow path 7 from the inlet 11 and exits through a separate secondary flow path outlet 12. However, the operating principle is the same as the first configuration, i.e., a pressure difference ΔP2 is generated between the two fluid flow restrictors 3, 4, which are at least partially arranged within the secondary flow path 7, and the force generated by this pressure difference ΔP2 is used to close the main fluid flow F0 flowing through the main flow path 2 by means of the piston / valve element 9.

[0098] Figure 4 A cross-sectional view of a complete flow control device 100 installed in a production column 101 according to the present invention is shown.

[0099] In addition to the flow control device 100, the production column 101 also includes: a base tube 102 in which the flow control device 100 is installed; a filter tube 103 surrounding the base tube 102 to prevent large solid particles such as sand or debris from entering the base tube 102; an outer sleeve 110 for securing one axial end of the filter tube 103 to the base tube 102; and a first inner sleeve 104 configured to secure the other axial end of the filter tube 103 to the base tube 102 and to establish an inner sleeve fluid passage 105 from the filter tube fluid passage oriented through or located below the filter tube 103 to the main fluid path inlet 1 and the secondary fluid path inlet 11 of the flow control device 100.

[0100] The production string 101 also includes a second inner sleeve 107 and an end cap 108. The second inner sleeve is arranged on the base tube 102 on the radial side of the flow control device 100 relative to the first inner sleeve 104. The end cap seals or comes close to sealing the flow control device 100 installed outside the production string 101, thereby creating a closed input chamber 109 established by the first inner sleeve 104, the second inner sleeve 107, the end cap 108, and the base tube 102.

[0101] During operation, fluid flows into the filter pipe fluid channel through the filter pipe 103, further along the inner sleeve fluid channel 105, through the inner sleeve opening 111 into the closed input chamber 109, and finally into the base pipe 102 through the flow control device 100.

[0102] As from Figure 4 It is evident that the space available for the flow control device 100 in a typical production string 101 is limited. It is advantageous that the main housing 8 of the flow control device 100 has a technically feasible minimum axial thickness t. AICD (i.e., the thickness perpendicular to the axial / longitudinal direction of the base tube 102 during installation) to avoid or minimize protrusion from the outer wall of the base tube 102 and / or entry into the interior of the base tube 102.

[0103] In particular, protrusion into the base tube 102 should be avoided, as this would interfere with measurements and / or maintenance and / or repair work that may be required / recommended within the base tube 102 throughout the entire operational life of the production string 101. Such operations typically involve inserting various devices into the base tube 102.

[0104] As described above, in order to ensure a large pressure differential on the first fluid flow restrictor 3, the ratio L / D 4 It should be relatively large. Furthermore, laminar flow can be obtained by generating a flow with a Reynolds number less than 4000, preferably less than 2500. This can be achieved by making the length L of the pipe constituting the first fluid flow restrictor 3 sufficiently large.

[0105] Figure 5 An embodiment is shown in which the flow control device 100 includes a coil used for laminar flow, which generates a first fluid flow restrictor 3 arranged within a secondary conduit 7. This is to ensure the laminar flow f of the secondary fluid flow through the secondary conduit 7. lam Furthermore, under large pressure differentials p1-p2, the coil 3 is made to be significantly longer than the axial thickness t of the main casing 8. AICD .

[0106] The first fluid flow restrictor 3 can be divided into an inner portion 3a located within the main housing 8, an outer straight portion 3b located outside the main housing 8 and in fluid communication with the inner portion 3a, and an outer coiled portion 3c located outside the main housing 8 and in fluid communication with the outer straight portion 3b. The outer coiled portion 3c preferably coils around the base tube 102 multiple times to minimize the space required in the longitudinal direction of the base tube 102, thereby minimizing dimensional interference between the flow control device 100 of the present invention and the existing production line 101. Simultaneously, the desired large pressure differential and laminar flow can be achieved.

[0107] The length L of the pipe and the axial thickness t of the main shell 8 AICD The ratio between them is preferably greater than 50, more preferably greater than 100, even more preferably greater than 200, and even more preferably greater than 300. In a typical installation, the pipe length L is 5 meters, and the axial thickness t AICD It is 14 millimeters.

[0108] Figure 6 A cross-section of the flow control device 100 is shown, which includes only the portion located within or near the main housing 8. (See diagram below.) Figure 4 As illustrated, the main housing 8, arranged within the wall of the base tube 102 during operation, shows a main inlet 1 and a secondary inlet 11 in fluid communication with the closed chamber 109 via a fluid inlet 20, and fluid flow outlets 5 and 12 in fluid communication with the interior of the base tube 102 of the production column 101.

[0109] exist Figure 5 The valve element 9, shown in Figure 9 as an axially movable piston / disc 9, is arranged within the main housing 8. The valve element 9 is housed within a toothed main fluid flow bushing 18, which provides lateral support to the piston 9 (see Figure 9). Figure 7 This allows for unrestricted axial piston movement. Lateral support means that piston 9 has little or no movement in the radial direction (i.e., at the mounting point parallel to the longitudinal axis of base tube 102).

[0110] Furthermore, the surfaces of the piston / valve element / movable disc 9 that are away from the main flow path inlet 1 and the secondary flow path inlet 11 are in a state of... Figure 6 In the illustrated configuration, an elastic member 10 is fixed to the adjacent inner wall of the main housing 8 at its outer circumference. The elastic member 10 transmits the resulting pressure to the piston 9 and ensures that the flow control device 100 is in an initial predetermined position, such as a fully open or fully closed position, before any fluid flow F. The elastic member 10 (e.g., a diaphragm) may be made of a semi-flexible material, such as an elastomer.

[0111] Special Reference Figure 7 and combined Figure 6 As can be seen, the bushing teeth 18a arranged on the outer periphery of the main fluid flow bushing 18 serve as both an axial gasket between the elastic member 10 below the piston 9 (i.e., near the inner side of the base tube 102) and the inlet bushing 16 above the piston 9 (i.e., near the outer side of the base tube 102) that forms the main flow path inlet 1. Furthermore, the bushing 18 includes a corresponding number of channel openings 18b between the teeth 18a to allow the main fluid flow F0 to flow radially through.

[0112] like Figure 7 As best shown, the piston 9 includes a lower plate 9a that contacts the elastic member 10 and an upper plate 9b centrally arranged on the lower plate 9a. The outer radial diameter of the lower plate 9a is equal to or approximately equal to the inner diameter of the toothed main flow bushing 18. The upper plate 9b is arranged / formed at the center of the lower plate 9a and has a radial diameter smaller than that of the lower plate 9a, for example, equal to or slightly larger than the minimum inner diameter of the main flow path inlet 1 and / or equal to or smaller than half the diameter of the lower plate 9a. However, it should be noted that the top surface of the piston 9 is not limited to the geometry of the plates. Any geometry of the piston 9 that allows the main flow path inlet 1 to be opened / closed is conceivable.

[0113] An example of a slightly larger diameter at the top of piston 9 could be a diameter less than 10% larger than the minimum inner diameter of the main flow path inlet 1.

[0114] exist Figure 6 In the diagram, the main flow path inlet 1 is formed in a separate inlet bushing 16. The inlet bushing 16 includes a funnel-shaped inlet with a smooth inner wall, thereby ensuring minimal turbulence during operation. In this document, a smooth inner wall means a wall without sharp edges and / or sharp protrusions.

[0115] To lock the piston / valve element 9, the main fluid flow bushing 18, and the elastic member 10 within the main housing 8, a locking ring 14 is arranged above the piston 9, its center surrounding the inlet bushing 16. The locking mechanism is achieved by an upper portion 14a having locking protrusions / teeth that insert into and / or engage with corresponding conduits within the internal opening of the main housing 8. The lower portion 14b of the locking ring 14 forms a tight fit with the inner diameter of the main housing 8. Furthermore, a sealing device 15 (e.g., an O-ring) is radially arranged between the lower portion 14b and the main housing 8 to prevent fluid leakage between them. However, this locking ring 14 can be secured to the main housing 8 in ways other than the locking protrusions 14a. For example, a configuration with external threads and / or a retaining ring is conceivable.

[0116] It should be noted that in another exemplary configuration, the inlet bushing 16 and the locking ring 14 can be made as a single solid part. However, the configuration described above with two separate parts 14, 16 has the advantage that a hard material (e.g., sintered tungsten carbide) can be selected for the inlet bushing 16 to prevent corrosion near the inlet 1 of the main flow path due to high speed and / or sudden changes in flow direction.

[0117] refer to Figure 5 As shown in Figure 8, the flow control device 100 also includes a top housing 19 disposed on the main housing 8, such that the inlet bushing 16 having the main flow path inlet 1 is covered. The top housing 19 is designed such that an inlet volume is formed between the top housing 19 and the main housing 8, wherein the main flow path inlet 1 is located below the volume at the same radial position as the main flow path inlet 1, and the secondary flow path inlet 11 is located above the volume.

[0118] exist Figure 5 The structure of the top shell 19, as seen in Figure 8, can be divided into two parts, 19a and 19c.

[0119] - Part 19a includes a fluid inlet 20 for allowing fluid flow F to enter the inlet volume and a vortex guide device 19b, and

[0120] - The second thicker portion 19c includes at least a length of the inner portion 3 of the coil 3.

[0121] The top housing 19 can be secured to the locking ring 14 by screws 19d.

[0122] As in Figure 6 and Figure 7 As best seen in the middle, the inner portion 3a of the coil 3 extends partly within the second portion 19c of the top housing 19 and partly within the main housing 8.

[0123] The vortex guide device 19b is configured to induce vortex motion on the fluid flow F when the fluid flow F enters the inlet volume. This can be achieved by, for example, from... Figure 9B The wedge structure 19B seen above in the cross-sectional view achieves this. Multiple wedges forming the wedge structure 19B define a deflection channel with a common deflection angle α relative to the radial orientation from the central axis of the main flow path inlet 1. Therefore, the value of the deflection angle α sets the vortex radius, which again affects the separation of the individual phases in the multiphase fluid flow F entering through the fluid flow inlet 20.

[0124] The vortex guide 19b can be from, for example Figure 9B The wedge-shaped structure is extruded from the disc as shown. Alternatively, it can form a separate part fixed to the top housing 19. It is also conceivable to configure the vortex guide 19b as having a user-adjustable deflection angle α.

[0125] As best seen in Figure 8, the locking ring 14 is sealed to the main housing 8 by an O-ring 15 that extends along the outer circumference of the lower portion of the locking ring 14, i.e., below the portion of the locking ring 14 with the locking protrusion.

[0126] The length of the internal segment 3a, including the secondary flow path inlet 11 within the top housing 19, is aligned with the internal segment 3a within the main housing 8, thereby creating the desired fluid communication. Furthermore, if fluid communication with the external straight portion 3b is established, the internal segment 3a is positioned from the opening in the main housing 8. Therefore, the secondary fluid flow f can pass through both the top housing 19 and the main housing 8 and enter the external straight portion 3b located outside the main housing 8. It further passes through the external coiled portion 3c and returns to the main housing 8 via one or more return channels 3d within the main housing 8. The return channels 3d guide (now) the laminar secondary fluid flow f. lam The fluid flows through a chamber B located below the piston 9 and the elastic member 10, further through a second fluid flow restrictor 4 in the form of an orifice, and exits through a secondary flow path outlet 12 within the outlet bushing 17. The orifice 4 is arranged within the outlet bushing 17, which is fixed in fluid communication with the secondary flow path outlet 12. The orifice 4 can be adjustable, thereby enabling regulation of the secondary fluid flow (f). tur The degree of turbulence. As explained above, due to the flow through orifice 4, the fluid characteristics of the secondary fluid flow f change from laminar to stratified. lam Change to tubular f tur .

[0127] In order to secure the flow control device 100 to the base tube 102, the main housing 8 shows a plurality of through holes 23, which are configured to receive a fixing device, such as a screw or bolt (not shown).

[0128] In operation, a fluid flow F (e.g., oil from an underground reservoir) is guided through a fluid flow inlet 20 into a top housing 19, which surrounds an inlet volume. The inlet volume is covered on its lower side by an inlet bushing 16 having a main flow path inlet 1, and on its upper side by a secondary flow path inlet 11. Upon entering the inlet volume, the fluid flow F is further divided into a main fluid flow F0 entering the main flow path / main pipe 2 through the main flow path inlet 1, and a smaller secondary fluid flow f entering the secondary flow path 7 through the secondary flow path inlet 11. The main fluid flow F0 follows the main pipe 2 before exiting the main housing 8 through the main flow path outlet 5 and entering the base pipe 102.

[0129] The remaining portion of the fluid flow F (i.e., the secondary fluid flow f) flows through the secondary pipe 7, that is, through the secondary flow path inlet 1, coil 3, chamber B, orifice 4, and finally enters the base pipe 102 via the secondary flow path outlet 12.

[0130] If water and / or natural gas enter fluid flow F during oil production, causing a decrease in total viscosity μ, the resulting difference in the value of P2 (ΔP2, see Figure 2) is used to apply pressure to the actuating surface 6 of piston 9 and the diaphragm 10 away from inlets 1, 11, 20. Figure 6 In the diagram, the actuating surface 6 is shown as part of a steel insert plate vulcanized to rubber (forming the diaphragm 10). This specific configuration is intended to help prevent clogging of the orifice 4. The pressure change ΔP2 acting on the actuating surface 6 generates a prime mover E2, which pushes the upper part 9b of the piston 9 toward the main flow path inlet 1, thereby preventing (or at least significantly limiting) the entry of additional main fluid flow F0 into the main housing 8. The diaphragm 10 ensures that the dominant elastic force or biasing force on the piston 9 is directed away from the main flow path inlet 1. As a result, when the main fluid flow F0 is absent or small enough to negate the elastic force, the piston 9 remains in the open position relative to the main flow path inlet 1.

[0131] It should be noted that the present invention is not limited to a specific material or geometry for all the above-described configurations. In fact, any choice of material and / or geometry is possible, as long as the two fluid restrictors 3 and 4 in the secondary conduit 7 produce a change in fluid characteristics; for example, one of the restrictors 3 and 4 produces primarily laminar flow. lam The other limiter generates primarily turbulent flow during operation. tur Furthermore, even though directional terms such as below, radial, and axial are used with reference to the accompanying drawings, it should be understood that these terms are used for clarity only and should not be construed as limiting the directional position of the control device 100 of the present invention.

[0132] All the components of the flow control device 100 of the present invention described above are autonomous in the sense that they are activated (for closing or opening the fluid inlet) solely based on the changing characteristics of the fluid F (e.g., viscosity μ). The internal dimensions of the coil 3, orifice 4, housing 8, top housing 19, and internally arranged bushing 18 can be designed to suit various applications.

[0133] To better illustrate the dynamics of the autonomous fluid flow control device 100 of the present invention, Figure 10 A schematic diagram of the flow control device 100, excluding the outer coiled portion 3c of the first fluid flow restrictor 3, is shown. The flow control device 100 is configured to prevent low-viscosity fluids such as natural gas and water from entering the desired flow phase of a high-viscosity fluid such as oil. The directions of various forces E1, E2, and E3 established by the main fluid flow F0 are indicated, along with the corresponding pressures p1, p2, and p3 and the affected cross-sectional areas A1, A2, and A3. To stop the main fluid flow F0, the force E2 (=p2*A2) acting on the actuating surface 6 exceeds the sum of the opposing forces acting on the opposite side of the piston 9 to a maximum extent, i.e., E1 (=p1*A1) + E3 (=p3*A3).

[0134] It should be understood that fluid flow restrictors 3 and 4 can be arranged and configured differently. For example, if the device is intended for use in a natural gas reservoir and it is desirable to prevent high-viscosity fluids such as water from entering production, fluid flow restrictors 3 and 4 can be reversed in the flow path.

[0135] It should also be understood that the flow control device 100 of the present invention can be arranged and configured to control and prevent the inflow of other fluids, such as CO2 (which has been injected into the reservoir) and steam (in combination with so-called steam-assisted gravity draining (SAGD) injection, such as heavy oil) and water in the gas production well.

[0136] Although the invention has been described with reference to the control of well-produced fluids (e.g., oil, natural gas, water) from underground reservoirs, those skilled in the art will understand that the apparatus and methods of the invention can be used in any application where the objective is to control fluid flow based on the properties (e.g., viscosity, density) of various fluids in the flow to prevent unwanted fluids from entering the fluid flow. Examples of such applications are injection wells, separation processes, and steam traps.

[0137] Figure label:

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Claims

1. A fluid flow control device (100) for establishing a controllable fluid connection of fluid flow (F) between an external fluid reservoir (120-122) and the base pipe (102) of a production string (101), comprising: - A main flow path (2), arranged within the main housing (8), the main flow path (2) including a main flow path inlet (1) and a main flow path outlet (5), the main flow path inlet being configured to guide the main fluid flow (F0) constituting the majority of the fluid flow (F) into the main housing (8) during operation, and the main flow path outlet being configured to guide the main fluid flow (F0) from the main housing (8) into the base pipe (102) during operation. - A secondary flow path (7), configured to guide the secondary fluid flow (f) constituting the remaining portion of the fluid flow (F), the secondary flow path (7) including a first fluid flow restrictor (3), a second fluid flow restrictor (4), and a chamber (B), the first fluid flow restrictor being configured to generate a pressure drop from a pressure p1 upstream of the first fluid flow restrictor (3) to a pressure p2 downstream of the first fluid flow restrictor (3), the second fluid flow restrictor being arranged downstream of the first fluid flow restrictor (3) and configured to generate a pressure drop from a pressure p2 upstream of the second fluid flow restrictor (4) to a pressure p3 downstream of the second fluid flow restrictor (4), the chamber being arranged downstream of the first fluid flow restrictor (3) and upstream of the second fluid flow restrictor (4), and - A movable valve element (9) is disposed within the main housing (8) and configured to close the main flow path (2) for fluid flow (F) when exposed to pressure exceeding a threshold pressure from the chamber (B). Its features are, The fluid flow control device (100) further includes: - A top housing (19) covering the main flow path inlet (1) of the main housing (8), the top housing (19) comprising: - Fluid inlet (20) allows the fluid flow (F) to flow from the external fluid reservoir (120-122) and at least partially flow into the main flow path inlet (1). - A vortex guide (19b) induces a vortex in the fluid flow (F) between the fluid flow inlet (20) and the main flow path inlet (1). - The secondary flow path inlet (11) is configured to guide the secondary flow (f) into the secondary flow path (7).

2. The fluid flow control device (100) according to claim 1, wherein, The top housing (19) also includes: - At least a portion of the secondary flow path (7), the at least a portion being arranged in fluid communication with the inlet (11) of the secondary flow path.

3. The fluid flow control device (100) according to claim 1 or 2, wherein, The secondary flow path inlet (11) enters a portion of the top housing (19) facing the main flow path inlet (1).

4. The fluid flow control device (100) according to claim 1, wherein, The secondary flow path inlet (11) is configured such that the secondary fluid flow (f) flows into the secondary flow path inlet (11) in the opposite direction to the main fluid flow (F0) during operation.

5. The fluid flow control device (100) according to claim 1, wherein, The vortex guide (19b) includes: - Multiple fluid flow deflectors are spaced apart from each other to form at least one vortex guide channel, the at least one vortex guide channel having a deflection angle (α) relative to the radial direction of the fluid flow control device (100), thereby setting the direction of the vortex of the fluid flow (F).

6. The fluid flow control device (100) according to claim 5, wherein, Each of the plurality of fluid flow deflectors has a wedge shape, and two of the conical sides of the wedge shape are oriented in the direction of the vortex.

7. The fluid flow control device (100) according to claim 1, wherein, The top shell (19) is divided into: The first radial portion (19a) includes: The fluid inlet (20), and The vortex guide (19b), and The second radial portion (19c) includes: The secondary flow path inlet (11), and At least a portion of the secondary flow path (7) that is in fluid communication with the secondary flow path inlet (11).

8. The fluid flow control device (100) according to claim 7, wherein, The second radial portion (19c) also includes at least a portion of the main flow path inlet (1).

9. The fluid flow control device (100) according to claim 7 or 8, wherein, The second radial portion (19c) is thicker than the first radial portion (19a), and wherein at least a portion of the secondary flow path (7) is oriented in the radial direction at an axial height equal to or higher than the axial height of the fluid inlet (20).

10. The fluid flow control device (100) according to claim 7, wherein, The radial boundary between the first radial portion (19a) and the second radial portion (19c) includes an axial wall having a deflection angle (α) relative to the radial direction of the fluid flow control device (100), thereby setting the direction of the vortex of the fluid flow (F).

11. The fluid flow control device (100) according to claim 1, wherein, The majority of the length of the secondary flow path (7) extends to the outside of the main housing (8).

12. A production tubing string for transporting oil and gas, wherein, The production tubing includes: - Base tube (102). - A sealing shell (104, 107, 108), disposed on the outer wall of the base tube (102), having at least one sealing shell inlet opening (111), and - The fluid flow control device (100) according to any one of claims 1 to 11. The fluid flow control device (100) is disposed in a through-hole in the wall of the base tube (102) within the housings (104, 107, 108), thereby achieving controllable fluid communication between the interiors of the housings (104, 107, 108) and the base tube (102). The enclosures (104, 107, 108) are configured to provide an input chamber (109) covering at least one enclosure input opening (111) of the enclosures (104, 107, 108) and the fluid inlet (20) of the fluid flow control device (100).

13. A method for controlling fluid flow (F) based on changes in fluid properties using a fluid flow control device (100) according to any one of claims 1 to 11, the method comprising the steps of: - The fluid flow (F) is directed into the fluid inlet (20). - The fluid flow (F) is guided through a vortex guide (19b) arranged between the fluid flow inlet (20) and the main flow path inlet (1) to generate a vortex of the fluid flow (F) around the main flow path inlet (1). - While the fluid flow (F) vortexes, the main fluid flow (F0) that constitutes most of the fluid flow (F) is guided through the main flow path inlet (1) within the main housing (8). as well as - The secondary fluid flow (f) is guided through the secondary flow path (7), and the secondary fluid flow (f) constitutes a small part of the fluid flow (F).

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