WO2022155739A1

WO2022155739A1 - Apparatuses, systems, and methods for fluid inflow control

Info

Publication number: WO2022155739A1
Application number: PCT/CA2022/050078
Authority: WO
Inventors: Xiaoqi Wang
Original assignee: Exceed (Canada) Oilfield Equipment Inc.; Nine Ring Machinery Share Holding Co., Ltd.
Priority date: 2021-01-19
Filing date: 2022-01-19
Publication date: 2022-07-28
Also published as: CA3181767A1

Abstract

An apparatus for restricting water in a fluid entering a base pipe in a wellbore. The apparatus has at least one inlet for receiving the fluid, an outlet, and a bore in fluid communication with the at least one inlet and the outlet. The bore has a first section coupled to the at least one inlet for decreasing a pressure of the fluid by increasing a velocity thereof, a second section coupled to the first section for allowing undersaturated or saturated water in the fluid to generate steam or allowing injected steam/vapor to expand its volume for partially or fully blocking the bore, a third section coupled to the second section for causing the remaining water and generated or injected steam to conduct work to the surrounding environment or expand to cause more volume of steam for partially or fully blocking the bore.

Description

APPARATUSES, SYSTEMS, AND METHODS FOR FLUID INFLOW CONTROL

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of US Provisional Patent Application Serial No. 63/139,077, filed January 19, 2021, the content of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to apparatuses, systems, and methods for controlling fluid to flow into a base pipe downhole in a well and in particular to apparatuses, systems, and methods for controlling water to flow into a base pipe downhole in a well while allowing hydrocarbon to flow thereinto.

BACKGROUND

Steam-assisted gravity drainage (SAGD) is a widely used, enhanced oil recovery technology for producing heavy crude oil and bitumen reserves. In a SAGD process, a pair of horizontal wells is drilled with one horizontal well (denoted the “injection well” or the “injector” hereinafter) positioned a few meters above the other well (denoted the “production well” or the “producer” hereinafter). Steam is continuously injected into a reservoir through the upper injection well. The steam heats the bitumen and reduces its viscosity, allowing the hydrocarbon to drain to the lower production well and be pumped to the surface.

The energy consumption of SAGD is highly dependent on steam requirements. The steam front can be heavily influenced by factors such as reservoir heterogeneity, fluid dynamics, and the distance the production zone is away from the downhole pump. Uniform steam-chamber growth (conformance) in a SAGD process promotes enhanced bitumen recovery, project economics, and environmental benefits. In contrast, uneven steam-chamber growth can lead to a high steam-oilratio and early breakthrough of steam and/or water in the producer, thereby negatively affecting the well economics and increasing the environmental footprint of the SAGD operation.

An inflow control device is a device used in well completions that may utilize fluid properties to dynamically adjust the wellbore pressure distribution and restrict the flow of undesired fluids (for example, steam and water) into the base pipe of the producer. This restriction forces the steam to penetrate back into the reservoir for better heating efficiency and evens out production along the length of the producer. The design and mechanisms of inflow control devices may also be applied to producers in other types of thermal oil recovery processes, for example, cyclic steam stimulation (CSS) and steam flooding. Therefore, there always exists a need for improved inflow control devices, systems, and methods to increase the efficiency and reduce the environmental impact of steam-based heavy crude and bitumen recovery processes.

SUMMARY

The present disclosure provides apparatus, systems, and methods for controlling fluid flow into a base pipe of a production well. An advantage of the present disclosure is the provision of apparatus, systems, and methods having improved characteristics over existing technologies.

According to one aspect of the present disclosure, there is provided an apparatus for restricting water and/or steam in a fluid entering a base pipe in a wellbore, the apparatus comprising: a body having an exterior end and an interior end; at least one inlet positioned on or about the exterior end of the body for receiving the fluid; and a bore in fluid communication with the at least one inlet and extending within the body to the interior end thereof, the bore comprising: a first section in fluid communication with the at least one inlet for decreasing a pressure of the fluid by increasing a velocity thereof; a second section coupled to the first section for allowing the undersaturated or saturated water in the fluid to generate steam or allowing the expansion of the injected steam/vapor for partially or fully restricting, inhibiting or blocking the bore; a third section coupled to the second section for causing remaining undersaturated or saturated water and the injected or generated steam to conduct work to surrounding environment of the bore to further decrease the pressure of the fluid or to further expand the volume thereof for generating more volume of steam for partially or fully restricting, inhibiting or blocking the bore; and an outlet for discharging remainder of the fluid into the base pipe as the hydrocarbon-enriched fluid.

According to one aspect of the present disclosure, there is provided an apparatus for coupling to a port on a sidewall of a base pipe in a wellbore, the apparatus comprising: a body having an exterior end and an interior end; at least one inlet positioned on or about the exterior end of the body for receiving a fluid, the fluid comprising water in at least one of a liquid phase and a gas phase; an outlet on or about the interior end of the body; and a bore extending within the body and in fluid communication with the at least one inlet and the outlet; the bore comprises: a first section in fluid communication with the at least one inlet for decreasing a pressure of the fluid by increasing a velocity thereof; a second section coupled to the first section for causing a volume of steam to at least restrict a flow of the fluid in the bore; and a third section coupled to the second section and in fluid communication with the outlet for causing more volume of steam to at least further restrict the flow of the fluid in the bore.

In some embodiments, the first section comprises a first end in fluid communication with the at least one inlet, a second end, and a first length defined therebetween, the first section having a first inner diameter (ID) continuously reducing from the first end to the second end with a maximum first ID at the first end.

In some embodiments, the second section extends from the second end to a third end with a second length defined therebetween, the second section having a uniform second ID equal to the first ID of the first section at the second end.

In some embodiments, the third section is coupled to the second section and is in fluid communication with the outlet for further decreasing the pressure or expanding the volume of the fluid for causing the more volume of steam to at least further restrict the flow of the fluid in the bore.

In some embodiments, the third section extends from the third end to a fourth end in fluid communication with the outlet, the third section having a third length defined between the third end and the fourth end, and the third section having a third ID continuously increasing from the third end to the fourth end with a maximum third ID at the fourth end.

In some embodiments, the third length is greater than the first length.

In some embodiments, the maximum third ID is greater than the second ID.

In some embodiments, the apparatus is configured for providing a steam volume fraction of at least 0.2 at the outlet with a mass flow rate within a predefined range.

According to one aspect of the present disclosure, there is provided an apparatus comprising: a body having an exterior end and an interior end; at least one inlet positioned about the exterior end of the body; an outlet on or about the interior end of the body; and a bore extending within the body and in fluid communication with the at least one inlet and the outlet; the bore comprises: a first section having a first end in fluid communication with the at least one inlet, a second end, and a first length defined therebetween, the first section having a first inner diameter (ID) continuously reducing from the first end to the second end with a maximum first ID at the first end; a second section extending from the second end to a third end with a second length defined therebetween, the second section having a uniform second ID equal to the first ID of the first section at the second end; and a third section extending from the third end to a fourth end in fluid communication with the outlet, the third section having a third length defined between the third end and the fourth end, and the third section having a third ID continuously increasing from the third end to the fourth end with a maximum third ID at the fourth end.

In some embodiments, the third length is greater than the first length.

In some embodiments, the maximum third ID is greater than the second ID.

In some embodiments, the first ID of the first section is linearly reduced from the first end to the second end. In some embodiments, the third ID of the third section is linearly increased from the third end to the fourth end.

In some embodiments, the maximum first ID and the second ID are in aratio between 3.0: 1 and 1.2: 1.

In some embodiments, the maximum third ID and the second ID are in a ratio of between 2.5: 1 and 1.2: 1.

In some embodiments, the third length and the first length are in a ratio of at least 2: 1.

In some embodiments, the at least one inlet is on a sidewall of the body adjacent the exterior end thereof.

In some embodiments, the at least one inlet is on an end-wall of the body at the exterior end thereof.

In some embodiments, the at least one inlets comprises two or more inlets.

In some embodiments, the apparatus is configured for providing a steam volume fraction of at least 0.2 at the fourth end with a mass flow rate within a predefined range.

According to one aspect of the present disclosure, there is provided a downhole system comprising: a base pipe having one or more ports on a sidewall thereof, each of the one or more ports receiving therein an apparatus as described above for directing the fluid into the base pipe; and at least one filter for filtering solids in the fluid and directing the fluid to the apparatus.

In some embodiments, the at least one filter is a sand screen.

In some embodiments, the system further comprises at least two isolation components.

In some embodiments, the at least two isolation components comprise at least two packers. According to one aspect of the present disclosure, there is provided a method for restricting water in a fluid entering a base pipe in a wellbore, the method comprising: (i) directing the fluid from a hydrocarbon reservoir into a channel towards the base pipe; (ii) decreasing a pressure of the fluid in the channel by increasing a velocity thereof; (iii) causing a volume of steam to at least restrict a flow of the fluid in the channel; and (iv) causing more volume of steam to at least further restrict the flow of the fluid in the channel.

In some embodiments, said causing the more volume of steam to at least further restrict the flow of the fluid in the channel comprises: further decreasing the pressure or expanding the volume of the fluid for causing the more volume of steam to at least further restrict the flow of the fluid in the channel.

In some embodiments, said decreasing the pressure of the fluid in the channel by increasing the velocity thereof comprises: directing the fluid through a first section of the channel, the first section comprising a first end, a second end, and a first length defined therebetween, the first section having a first inner diameter (ID) continuously reducing from the first end to the second end with a maximum first ID at the first end.

In some embodiments, said causing steam to at least restrict the flow of the fluid in the channel comprises: directing the fluid through a second section of the channel, the second section extending from the second end to a third end with a second length defined therebetween, the second section having a uniform second ID equal to the first ID of the first section at the second end.

In some embodiments, said causing the more volume of steam to at least further restrict the flow of the fluid in the channel comprises: directing the fluid through a third section of the channel, the third section extending from the third end to a fourth end in fluid communication with the outlet, the third section having a third length defined between the third end and the fourth end, and the third section having a third ID continuously increasing from the third end to the fourth end with a maximum third ID at the fourth end.

In some embodiments, the method further comprises: providing a steam volume fraction of at least 0.2 at an exit point of the channel with a mass flow rate within a predefined range.

In some embodiments, the method further comprises: directing the fluid through at least one solids filter prior to directing the fluid into the channel.

In some embodiments, the method further comprises: isolating a section of the well about the base pipe.

Other aspects and embodiments of the disclosure are evident in view of the detailed description provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present disclosure will become more apparent in the following detailed description in which reference is made to the appended drawings. The appended drawings illustrate one or more embodiments of the present disclosure by way of example only and are not to be construed as limiting the scope of the present disclosure.

FIG. 1 is a schematic diagram of a steam-assisted gravity drainage (SAGD) well pair comprising an injection well (the injector) and a production well (the producer), according to an embodiment of this disclosure, wherein the producer is equipped with an inflow-control apparatus;

FIG. 2 is a schematic diagram of an exemplary producer in a cyclic steam stimulation (CSS) or steam flooding process, according to an embodiment of this disclosure, wherein the producer is equipped with an inflow-control apparatus;

FIG. 3A is a perspective view of the inflow-control apparatus shown in FIG. 1 or FIG. 2, according to an embodiment of the present disclosure; FIG. 3B is a cross-sectional view of the inflow-control apparatus shown in FIG. 3A along the cross-section line B-B;

FIG. 3C is a cross-sectional view of the inflow-control apparatus shown in FIG. 3A along the cross-section line C-C;

FIG. 4 is a cross-sectional view of the inflow-control apparatus shown in FIG. 3A along the cross-section line C-C, showing the parameters thereof;

FIG. 5A is a side view of a base pipe, wherein the base pipe comprises a first portion having a plurality of ports on the sidewall thereof and a second portion having a plurality of ribs radially outwardly extending from the sidewall and circumferentially uniformly distributed thereon;

FIG. 5B is a side view of the base pipe shown in FIG. 5 A with a plurality of inflow-control apparatuses shown in FIG. 3A received in respective ports and wires wrapping on the ribs and secured to the base pipe via an end-piece;

FIG. 5C is a side view of the base pipe shown in FIG. 5B, wherein the first portion of the base pipe is received in a housing;

FIG. 5D is a cross-sectional view of the base pipe shown in FIG. 5C along the cross-section line D-D;

FIG. 6 is a schematic diagram showing a portion of a downhole oil production system, according to an embodiment of the present disclosure;

FIG. 7 is a flowchart showing an exemplary process for controlling the flow of a fluid into a base pipe of a production well, according to an embodiment of the present disclosure;

FIG. 8 is a flowchart showing an exemplary process for controlling the flow of a fluid into a base pipe of a production well, according to another embodiment of the present disclosure;

FIG. 9 shows a plot of steam volume fraction to mass flow rate, used to analyze the performance of the inflow-control apparatus shown in FIG. 3A;

FIG. 10 shows critical cross-sections for the flow mechanisms when saturated or near saturated water and/or steam passes through an inflow-control apparatus shown in FIG. 3A, according to the present disclosure;

FIG. 11 shows a Pressure-Temperature Phase Equilibrium Diagram of solid-liquid-gas phase between ice, water, and steam;

FIG. 12 shows a Pressure-Enthalpy Phase Equilibrium diagram between water and steam;

FIG. 13 shows a plot of pressure drop to mass flow rate for water with a steam flash mechanism, heat oil at typical downhole conditions, and a hypothetical water that does not have flashing capabilities, which is used to analyze the performance of the inflow-control apparatus shown in FIG. 3A; FIGs. 14A and 14B show model images of the mainstream flashed vapor from the water phase in an inflow-control apparatus shown in FIG. 3A, according to the present disclosure (FIG. 14 A) and an inflow-control apparatus not having the features of the inflow-control apparatus of the present disclosure (FIG. 14B);

FIG. 15 A shows the testing results of the pressure differences between the inlet and outlet of the inflow-control apparatus shown in FIG. 3A under different testing conditions;

FIG. 15B shows the testing results of the steam volume fractions at the inlet and outlet of the inflow-control apparatus shown in FIG. 3A under different testing conditions;

FIG. 16 is a cross-sectional view of the inflow-control apparatus shown in FIG. 1 or FIG. 2, according to an embodiment of the present disclosure;

FIG. 17 is a cross-sectional view of the inflow-control apparatus shown in FIG. 1 or FIG. 2, according to another embodiment of the present disclosure; and

FIG. 18 is a cross-sectional view of a base pipe shown with a plurality of inflow-control apparatuses shown in FIG. 16 received in respective ports, according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Unless otherwise defined, all technical and scientific terms used herein generally have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Exemplary terms are defined below for ease in understanding the subject matter of the present disclosure.

Herein, the term “about”, when referring to a measurable value (for example, a dimension), is meant to encompass variations of ±10%, ±5%, ±1%, ±0.5% or ±0.1% of the specified amount. When the value is a whole number, the term about is meant to encompass decimal values, as well the degree of variation just described.

The term “comprise” as is used in this description and in the claims, and its conjugations, is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded.

The present disclosure provides improved apparatus, systems, and methods for controlling flow of fluids into a base pipe of a production well. As used herein, the term “production well” is intended to refer to a well from which a hydrocarbon is recovered and, as appreciated by the skilled person in the art, may be interchangeably used with the term “producer”. In some embodiments, a production well may be a horizontal well in steam-assisted gravity drainage (SAGD) operations. In some other embodiments, a production well may be a horizontal well in cyclic steam stimulation (CSS) or steam flooding operations. The skilled person in the art will appreciate that while embodiments of the present disclosure are described in the context of horizontal wells, use in vertical wells is applicable. For example, in some embodiments, a production well may be a vertical well in a CSS or a steam-flooding operation.

Embodiments of the present disclosure will now be described with reference to FIG. 1 through FIG. 18, which show non-limiting embodiments of the present disclosure.

FIG. 1 and FIG. 2 show exemplary enhanced hydrocarbon-recovery processes for which the apparatus, systems, and methods of the present disclosure may be used. For ease of description, the terms “hydrocarbon”, “bitumen”, and “oil” may be used interchangeably hereinafter.

FIG. 1 shows an exemplary SAGD process for recovering bitumen from a reservoir 20, according to an embodiment of this disclosure. In this embodiment, steam is injected from the surface into the reservoir 20 through an injection well 10 (steam flow indicated by arrows 18 in injection well 10). As the steam heats bitumen in the reservoir 20, the viscosity of the bitumen is reduced and the bitumen drains towards a production well 12. The bitumen is brought to surface through a base pipe 14 of the production well 12 using a pump 16. As used herein, the term “base pipe” is intended to refer to a tubular, a tubing, a liner, or the like in a cased or uncased production well, or a perforated casing in a production well. Fluids from a reservoir are generally brought to the surface through the base pipe. In this embodiment, one or more inflow-control apparatuses 100 may be coupled to the base pipe 14 for controlling fluid flow into the base pipe 14.

FIG. 2 shows an exemplary CSS producer for recovering bitumen from reservoir 20 through the base pipe 14, according to an embodiment of this disclosure. In this embodiment, the base pipe 14 comprises one or more inflow-control apparatuses 100 for controlling fluid flow into the base pipe 14.

FIG. 3 A is a perspective view of the inflow-control apparatus 100 according to an embodiment of this disclosure. FIG. 3B is a cross-sectional view of the apparatus 100 shown in FIG. 3 A along the cross-section line B-B. FIG. 3C is a cross-sectional view of the apparatus 100 shown in FIG. 3A along the cross-section line C-C.

As those skilled in the art will appreciate, the inflow-control apparatus 100 may improve the steam-to-oil ratio in SAGD and/or CSS processes.

As shown in FIGs. 3A to 3C, the inflow-control apparatus 100 comprises a body 110 having an exterior end 110A, an interior end HOB, and a central axis A-A defined therebetween. As used herein, the term “exterior end” is intended to refer to the terminus of the body 110 that is facing the exterior side of the base pipe 14 when the apparatus 100 is operationally coupled to the base pipe 14. As used herein, the term “interior end” is intended to refer to the terminus of the body 110 facing the interior side of the base pipe 14 when the apparatus 100 is operationally coupled to the base pipe 14. By “operationally coupled to” it is meant that the apparatus 100 is coupled to the base pipe 14 in a position to control fluid flow into the base pipe 14.

The body 110 may be of any suitable shape and size and made of any suitable material. For example, in various embodiments, the exterior end 110A may comprise a hexagonal profile, a circular profile, or an octagonal profile from a plan view. In an embodiment, the body 110 comprises a metal or a metal alloy. In another embodiment, the body 110 comprises steel such as conventional steel or high tensile steel.

In the embodiment shown in FIGs. 3A to 3C, the body 110 comprises a head portion 114 on the exterior side thereof and a coupling portion 112 on the interior side thereof. The coupling portion 112 comprises threads 116 on the outer surface thereof for coupling to a threaded port on the sidewall of the base pipe 14 (that is, a so-called “threaded connection”; see FIGs. 5A and 5B). Of course, those skilled in the art will appreciate that in other embodiments, other suitable coupling structure such as for example a pin, a compression fitting, a flange, welding, or the like may be used for coupling the inflow-control apparatus 100 (or more specifically the coupling portion 112) to the port of the base pipe 14.

In this embodiment, the head portion 114 of the body 110 comprises at least one inlet 120 for introducing a fluid into the base pipe 14 (described in more detail later). Each of the at least one inlet 120 radially inwardly extends from the outer surface of the side wall of the head portion 114 to a central bore 130 extending from a position in the head portion 114 in proximity with the exterior end 110A to the interior end HOB of the body 110. The at least one inlet 120 and the central bore 130 thus form a channel for directing fluid from the exterior (outside of the exterior end 110A) towards the interior end HOB. In various embodiments, the at least one inlet 120 may comprise any suitable shape and size, and may be perpendicular to the central axis A-A of the body 110 or at an angle thereto. In embodiments where the head portion 114 comprises a plurality of inlets 120, it may be preferable that the inlets 120 are circumferentially uniformly distributed around the perimeter of the head portion 114.

In this embodiment, the central bore 130 is coaxial with the axis A-A. As will be appreciated, by “coaxial with the axis” it is meant that the central bore 130 is symmetric about the axis A-A. As shown in FIG. 4, the central bore 130 in this embodiment comprises, naming from the exterior side to the interior side thereof, a convergent section 132, a throat section 134, and a divergent section 136.

The convergent section 132 of the central bore 130 extends from the exterior end 110A (also denoted as the first convergent end 132A of the convergent section 132) to a second convergent end 132B with a continuously reduced inner diameter (ID) D_c and a length Lc defined therebetween. For example, as shown in FIG. 4, the convergent section 132 of the central bore 130 may have a conical frustum shape with the ID thereof linearly reducing from the first convergent end 132A to the second convergent end 132B thereof.

The throat section 134 extends from the second convergent end 132B of the convergent section 132 (also denoted as the first throat end 134A of the throat section 134) to a second throat end 134B with a uniform ID DT and a length LT defined therebetween. Herein, the term “uniform ID of the throat section” refers to the ID DT of the throat section which remains substantially or completely unchanged over the entire length thereof. For example, as shown in FIG. 4, the throat section 134 of the central bore 130 may have a cylindrical shape with the ID DT substantially equal to the ID D_c of the convergent section 132 at the second convergent end 132B. In this example, the length LT of the throat section 134 is less than the length L_c of the convergent section 132.

The divergent section 136 extends from the second throat end 134B of the throat section 134 (also denoted as the first divergent end 136A of the divergent section 136) to the interior end HOB (also denoted as the second divergent end 136B of the divergent section 136, which is also the outlet of the bore 130) with a continuously increasing ID DD and a length LD defined therebetween. For example, as shown in FIG. 4, the divergent section 136 of the central bore 130 may have a conical frustum shape. More specifically, the ID DD of the divergent section 136 as shown in FIG. 4 has its minimum at the first divergent end 136A substantially equal to the ID DT of the throat section 134, and linearly increases to its maximum at the second divergent end 136B. In this embodiment, the length LD of the divergent section 136 is greater than the length Lc of the convergent section 132.

The inflow-control apparatus 100 disclosed herein may be used in various applications such as SAGD and/or CSS for cavitating, flashing, or expanding undersaturated or saturated water to steam or vapor and preventing the water from going into the base pipe 14. Herein, the term “water”, unless otherwise explicitly specified, refers to water in the liquid phase, and terms “steam” and “vapor” (which may be used interchangeably) refer to water in the gas phase.

In an embodiment, the inflow-control apparatus 100 may provide a steam volume fraction (SVF) of at least 0.2 at the second divergent end 136B with a mass flow rate within a predefined range. As will be appreciated, the term “steam volume fraction” of a mixture of water and steam/vapor is the volume of the constituent steam measured as the volume thereof prior to mixing, divided by the total volume of the constituent steam and water of the mixture measured as the volumes thereof prior to mixing, the term “saturated water” refers to water that is at temperature and pressure conditions where the liquid is about to vaporize, and the term “undersaturated water” refers to water that is a few degrees (for example, about 3°C to 20°C) lower than its saturation temperature at the corresponding pressure. In an embodiment, the inflow-control apparatus 100 may provide a steam volume fraction of at least 0.2 (for example, about 0.2 to 0.95 in some embodiments) at the second divergent end 136B with the mass flow rate at the second divergent end 136B within a predefined range. Such a mass flow rate for achieving a steam volume fraction of at least 0.2 at the second divergent end 136B may vary depending on the dimensions of the inflow-control apparatus 100. In a particular embodiment, the inflow-control apparatus 100 may provide a steam volume fraction of at least 0.2 at the second divergent end 136B with a mass flow rate of about 0.08 kilogram per second (kg/s) to about 0.2 kg/s.

The parameters of the inflow-control apparatus 100 may be carefully selected for achieving an improved inflow control performance. For example, in an embodiment, the maximum ID De of the convergent section 132 and the ID DT of the throat section 134 are in a ratio of less than or equal to about 3:1. In an embodiment, the maximum ID De of the convergent section 132 and the ID DT of the throat section 134 are in a ratio of between 3.0: 1 and 1.2:1. For example, in some embodiments, the maximum ID De of the convergent section 132 and the ID DT of the throat section 134 may be in a ratio of about 2.9:1, 2.8:1, 2.7:1, 2.6:1, 2.5:1, 2.4:1, 2.3:1, 2.2:1, 2.1:1, 2:1, 1.9: 1, 1.8:1, 1.7:1, 1.6: 1, 1.5:1, 1.4:1, 1.3:1, or 1.2:1. In a particular embodiment, the maximum ID De of the convergent section 132 and the ID DT of the throat section 134 may be in a ratio of 2:1.

In an embodiment, the maximum ID DD of the divergent section 136 and the ID DT of the throat section 134 are in a ratio less than or equal to about 2.5:1. In an embodiment, the maximum ID DD of the divergent section 136 and the ID DT of the throat section 134 are in a ratio of between 2.5:1 and 1.2:1. For example, in some embodiments, the maximum ID DD of the divergent section 136 and the ID DT of the throat section 134 are in a ratio of 2.4:1, 2.3:1, 2.2:1, 2.1:1, 2: 1, 1.9:1, 1.8:1, 1.7:1, .6:1, 1.5:1, 1.4:1, 1.3:1, or 1.2:1. In a particular embodiment, the maximum ID DD of the divergent section 136 and the ID DT of the throat section 134 are in a ratio of 2:1.

In an embodiment, the length LD of the divergent section 136 and the length Lc of the convergent section 132 are in a ratio greater than or equal to 2:1. For example, in some embodiments, the length LD of the divergent section 136 and the length Lc of the convergent section 132 are in aratio of 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6: 1, 2.7:1, 2.8:1, 2.9: 1, 3:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7: 1, 3.8:1, 3.9:1, 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7: 1, 4.8: 1, 4.9:1, or 5: 1. In a particular embodiment, the length LD of the divergent section 136 and the length Lc ofthe convergent section 132 are in a ratio of 3.5:1.

The inflow-control apparatus 100 of the present disclosure may provide an environment for flashed vapor from water phase and/or injected steam to conform to the wall of the divergent zone 136. Further, the apparatus 100 of the present disclosure may increase the amount of flashed steam and/or the volume of the injected steam as compared to existing inflow control device technologies.

FIG. 3B is the schematic cross-sectional view of the inflow-control apparatus 100, showing the six inlet channels 120, the second convergent end 132B, the throat section 134, and the second divergent end 136B. In this embodiment, the six inlet channels 120 are equally spaced apart around the perimeter of the exterior end 110A, and each of the six inlet channels 120 is perpendicular to the axis A-A of the body 110. As those skilled in the art will appreciate, such a perpendicular arrangement between the inlet channels 120 and the axis of the body 110 may prevent the fluid inflow from forming a vortex or tortuous flow in the inflow-control apparatus 100.

FIGs. 5A to 5D show the assembling of an inflow-control assembly 200 having a plurality of the inflow-control apparatus 100.

FIG. 5A shows a base pipe 14 comprising a first portion having a plurality of ports 210 on the sidewall 212 thereof and a second portion having a plurality of ribs 214 radially outwardly extending from the sidewall 212 and circumferentially uniformly distributed thereon.

FIG. 5B shows the base pipe 14 with a plurality of inflow-control apparatuses 100 received in respective ports 210 and wires 216 wrapping on the ribs 214 and secured to the base pipe 14 via an end-piece 218 thereby forming a solids filter or screen 220.

FIG. 5C illustrates the base pipe 14 shown in FIG. 5B with the first portion received in a housing 232. FIG. 5D is a cross-sectional view of the base pipe 14 shown in FIG. 5C along the cross-section line D-D.

As shown, the housing 232 comprises an end-wall 234 on a first end and engages the solids filter 220 on a second end longitudinally opposite to the first end. The housing 232 and the first portion of the base pipe 14 form an annulus 242 in fluid communication with the annulus 244 between the solids filter 220 and the base pipe 14. The end-wall 234 of the housing 232 and the end-piece 218 of the solids filter 220 sealingly enclose the annuluses 242 and 244.

FIG. 6 is a schematic diagram showing a portion of a downhole oil production system 300 such as a SAGD system, according to some embodiments of the present disclosure. As shown, the system 300 comprises the base pipe 14 extended in a wellbore 302 within a reservoir 20 and having the inflow-control assembly 200 shown in FIGs. 5C and 5D installed thereon. In these embodiments, the wellbore 302 may be an injection well or a production well, and may be cased or uncased.

A pair of packers 304 are coupled to the base pipe 14 and engages the wellbore 302 for sealingly enclosing a portion of the annulus 306 between the base pipe 14 and the wellbore 302. In the embodiments wherein the wellbore 302 is a cased wellbore, the portion enclosed between the packers 304 is perforated for allowing a fluid 308 (which generally comprises water and hydrocarbon with solids (for example, sand) suspending therein) to flow from the reservoir 20 into the enclosed annulus 306.

The base pipe 14 between the packers 304 comprises the ports 210 each receiving therein an inflow-control apparatus 100 (see FIGs. 5C and 5D), thereby forming a plurality of inflowcontrol ports.

In operation, the fluid 308 flows from the reservoir 20 through the solids fdter 220 into the annulus 244 with at least a substantive portion of the solids contained therein being fdtered out. The fdtered fluid then flows through the annuluses 244 and 242 into the inflow-control apparatuses 100 wherein a substantive portion of water is rejected while the hydrocarbon thereof (as well as a reduced amount of water) continues to flow into the base pipe 14.

FIG. 7 shows a process 500 for controlling the flow of a fluid into a base pipe 14 of a production well, according to an embodiment of this disclosure. In this embodiment, the base pipe 14 comprises a plurality of inflow-control ports on the sidewall thereof (for example, a plurality of ports 210 coupling with a plurality of inflow-control apparatuses 100 as described above). The process 500 comprises:

Step 502: directing the fluid from a hydrocarbon reservoir into the plurality of inflowcontrol ports and flowing along respective channels towards the interior of the base pipe 14 by, for example, directing the fluid through the at least one inlet 120 of the inflow-control apparatus 100 in each ports 120 and flowing along the bore 130 towards the interior of the base pipe 14. In an embodiment, step 502 comprises draining the fluid by gravity after heating a hydrocarbon-containing reservoir with steam.

Step 504: decreasing the pressure (that is, causing pressure drop) of the fluid by increasing the velocity thereof. The increasing of the velocity of the fluid may be achieved by, for example, directing the fluid through the converging section 132 of the central bore 130 of the inflow-control apparatus 100 in each port 120.

Step 506: allowing undersaturated or saturated water contained in the fluid (if any) to sufficiently “flash” or vaporize to steam and/or allowing injected steam/vapor to expand its volume by, for example, directing the pressure-decreased fluid through the throat section 134 of the central bore 130 of the inflow-control apparatus 100 in each port 120. As will be appreciated, the term “flashing” refers to vaporization that occurs when an undersaturated or saturated liquid, such as for example saturated or near saturated water (for example, typically within 0°C to 10°C lower than the saturation temperature at the corresponding pressure), undergoes a reduction in pressure. As will be appreciated, the term “expanding” refers to the volume expansion that occurs when an injected steam or vapor undergoes a change in pressure and temperature. Step 508: causing the mixed water and steam (if any) to conduct work to the surrounding environment by expanding the fluid volume, for example, directing the mixed liquid and steam through the divergent section 136. In some embodiments, the steam volume at the second divergent end 136B may be 1% to 20% larger in comparison to that at the second throat end 134B. If associated with further pressure decrease in this step, it may cause water in the fluid (if any) to further vaporize to steam.

Subsequently, the steam generated in steps 506 and 508 (if any), while being discharged into the interior of the base pipe 14, partially or fully restricts, inhibits, or blocks the channel (for example, the bore 130 of the inflow-control apparatus 100) and partially or fully prevents fluid from flowing into the interior of the base pipe 14. In an embodiment, step 508 comprises providing a steam volume fraction of at least 0.2 at an exit point of the inflow-control apparatus 100, such as for example, the second divergent end 136B, with a mass flow rate within a predefined range.

Step 510: if the channel is not fully blocked, directing the fluid into the base pipe 14. Those skilled in the art will appreciate that the fluid directed into the base pipe 14 is a hydrocarbon- enriched fluid as otherwise the water therein may be vaporized to steam and block the channel. In an embodiment, step 510 comprises discharging the hydrocarbon-enriched fluid at the second divergent end 136B of the inflow-control apparatus.

As those skilled in the art will appreciate, during SAGD or CSS operations, the water temperature at some spots (sometimes denoted as “hot spots”) adjacent the base pipe 14 is relatively lower than the pre-set subcool temperature which is typically defined and targeted at about 10°C to 15°C lower than the saturation temperature at the bottom-hole operating pressure. Suitable inflow-control apparatuses 100 may be used at such hot spots to prevent hot water or following steam from entering the base pipe 14.

Those skilled in the art will also appreciate that the water distribution in the subterranean environment about the base pipe 14 is usually non-uniform. Therefore, by deploying a plurality of inflow-control apparatuses 100 on the base pipe 14, the inflow-control apparatuses 100 in the water-rich zones may vaporize saturated and/or near saturated water to partially or fully block the water-rich fluid from entering the base pipe 14. On the other hand, the inflow-control apparatuses 100 in the hydrocarbon-rich zones (that is, with less or no water) would generate little or no steam and thus allow the hydrocarbon-rich fluid to enter the base pipe 14.

More specifically, in some situations, water and heated oil are not mixed as emulsion and may flow mainly separately from reservoir to the base pipe 14. In such situations, the inflowcontrol apparatus 100 may flash the saturated or near saturated water into a steam- water-mixed fluid (for example, a fluid containing more than 20% steam on volume basis) to block the fluid (which is water-rich) to enter the base pipe 14. In some situations, the fluid may be a well-mixed emulsion such as an emulsion of 50% water and 50% oil. When the fluid flows through the inflow-control apparatus 100, the water therein may be flashed into steam in a limited amount depending on how the emulsion is formed. Thus, the inflow-control apparatus 100 may mitigate the contained water by flashing it into steam to some extent while still allowing oil to flow therethough.

In some situations, the fluid may contain little or no water. Therefore, little or no steam is generated when the fluid passes through the inflow-control apparatus 100 and subsequently the fluid (which mainly or fully contains oil) flows through inflow-control apparatus 100 into the base pipe 14 for collection.

FIG. 8 shows a process 540 for collecting oil into a base pipe 14 with controlled water entrance, according to one embodiment of this disclosure. As shown, the process 540 comprises:

Step 542: deploying the base pipe 14 (which may be a portion of a casing string or a tubing string) downhole into a well in a hydrocarbon reservoir.

Step 544: isolating a section of the well about the base pipe 14 using an isolation device such as a pair of packers.

Step 546: passing the fluid from the reservoir through at least one solids filter.

Step 548: performing the inflow-control process 500 as described above.

Step 550: collecting hydrocarbon-enriched fluid in the base pipe 14.

FIG. 9 shows a plot of steam volume fraction (SVF) to mass flow rate for a particular embodiment of the inflow-control apparatus 100. Two different regions (Region 1 and Region 2) and a Turning Point in a transition zone between the Region 1 and Region 2 may be identified. As can be seen, when mass flow rates of the flashed water are lower than a certain first value (for example, 0.06 kg/s) the profile of SVF versus mass flow rate shows an abrupt increase with a minimum slope of 10 from a lower mass flow rate. In contrast, when mass flow rates of the flashed water are higher than a certain second value, (for example, 0.07 kg/s), the profile of SVF versus mass flow rate turns into a much slower or near plateau. A turning point (for example, about 0.06 kg/s) between these two different regions may be located by intersecting the two major slopes of the two curves.

The inflow-control apparatus 100 of the present disclosure may operate in a stable operating condition with improved inflow control capabilities when the mass flow rate exceeds a threshold mass flow rate corresponding to the turning point. In some embodiments, the inflowcontrol apparatus 100 may be designed based on the main operating condition. For example, in a typical SAGD operation with the inflow-control apparatuses 100 installed, the SAGD producer’s production rate may normally correspond to a wide range of 0.025 kg/s to 0.20 kg/s and may also be specific to each well. Therefore, after the target threshold mass flow rate is determined based on the well condition, the dimensions of the inflow-control apparatus 100 may be determined in accordance with above-described ratios between the sections of the bore 130. For example, in an embodiment, the threshold mass flow rate of the inflow-control apparatus 100 may be between about 0.025 kg/s to about 0.20 kg/s. In a particular embodiment, the threshold mass flow rate of the inflow-control apparatus 100 may be about 0.06 kg/s.

When a fluid flows through an inflow-control apparatus 100 of the present disclosure, a pressure drop may occur depending on the structure of the inflow-control apparatus 100 and the specific properties of the incoming fluid. As described above and will be further described later, the pressure drop of an unwanted fluid, for example undersaturated or saturated water or injected steam, comprises the pressure drop occurred in the convergent section 132 and the throat section 134, and the additional pressure drop occurred in the divergent section 136.

To prevent or mitigate the unwanted fluid, for example undersaturated or saturated water, from entering the base pipe 14 and subsequently being produced to surface, the different characteristics of the undersaturated or saturated water in comparison to the those of the heated oil at downhole conditions may be utilized. When the undersaturated or saturated water flows through the inflow-control apparatus 100 of the present disclosure, the pressure drop may cause a considerable amount of steam to flash out of the water (that is, in the liquid phase) into the vapor (that is, in the gas phase), or cause a substantial expansion of the volume of the injected steam. The suddenly appearing vapor phase and/or significantly increased volume of the vapor phase may fill the central bore 130 and result in a further increase of the pressure drop across the inflowcontrol apparatus 100. Generally, the pressure drops caused by various reasons leads to vaporization of water and the generated steam or the expansion of the inj ected steam may partially or fully prevent the fluid (which is generally a water-rich fluid) from entering the base pipe 14.

“Cavitation” or “flashing” occurs when the static pressure of a liquid reduces to below the liquid’s vapor pressure, leading to the formation of small vapor-filled cavities in the liquid. When the undersaturated or saturated water or a mixture of water and steam/vapor passes through the inflow-control apparatus 100, hydrodynamic cavitation may be produced.

The level of cavitation typically depends on the geometry of the inflow-control apparatus 100, environmental conditions (such as pressure and/or temperature), the characteristics of the injected fluid, the injection rate, and/or the like. A lower level of cavitation may generate a slight increase of pressure drop across the inflow-control apparatus 100 due to a partial restriction of the fluid flow. On other hand, a higher level of cavitation may create a sharp increase of pressure drop as the flashed vapor bubbles block a large area of the bore 130.

When the velocity of the flashed vapor in inflow-control apparatus 100 reaches the local sonic speed in the flow medium (that is, the speed of an acoustic wave at a particular location in the flow medium), “supercavitation” condition is developed, which means that the bore 130 of the inflow-control apparatus 100 is “choked” and is not capable of passing more flow (for example, the velocity of the fluid flow does not increase while the pressure at the outlet 136B of the inflowcontrol apparatus 100 further decreases). In a two-phase liquid-vapor mixture system, the sonic speed is much smaller than that in the pure steam/vapor or pure water. This is mainly because of the heat and mass transfer between the phases to maintain thermal equilibrium and the generated vaporization waves when a liquid is converted to a vapor. Therefore, in atypical SAGD operation, when unwanted fluids such as the undersaturated or saturated water and steam/vapor flow through the downhole inflow-control apparatus, the supercavitation or choke condition is relatively easy to achieve in comparison to flowing pure water or pure steam/vapor through an inflow-control apparatus 100.

On the other hand, when the heated oil flows through the inflow-control apparatus 100 of the present disclosure, the pressure drop is much lower than that that of the undersaturated or saturated water since there is substantially no oil-vapor or gas-phase oil flashed out of the liquidphase oil. Therefore, a hydrocarbon-rich fluid will not be prevented or mitigated from entering the base pipe 14 and being produced to surface.

The structure and dimensions of the inflow-control apparatus 100 of the present disclosure advantageously allows for both fluid mechanics and thermodynamic theories to take place to provide a sufficiently high pressure drop when a fluid containing water flows through and thus flash out a significant volume of steam from water for blocking the fluid to enter the base pipe 14, thereby selectively blocking water-rich and/or steam-rich fluids and allowing hydrocarbon-rich fluid to flow into the base pipe 14.

In particular, when the undersaturated water flows through the convergent section 132 from the cross-section A to cross-section Bi (see FIG. 10), the Bernoulli effect from fluid mechanics theory takes into effect (see Equation (1)).

wherein PA represents the fluid average pressure at cross-section A,p represents the fluid density, VA represents the fluid average velocity at cross-section A, VBI represents the fluid average velocity at cross-section Bi, g represents the standard gravity, h.\ represents the height at cross-section A above a reference plane (for example, cross-section C), hB represents the height at cross-section Bl above a reference plane (for example, cross-section C), PBI represents the fluid average pressure at cross-section Bi, w A H friction A-BI represents the friction loss in energy.

More specifically, as the cross-section area is continuously reduced from A to Bi, the velocity of the undersaturated water at cross-section Bi is much larger than that at cross-section A, that is, v_B1 > v_A. Since the position difference and friction loss from A to Bi may be negligible, the pressure of cross-section Bi is significantly lower than that of cross-section A, that is, BI < PA-

For example, as the pressure of undersaturated water is reduced from cross-section A to Bi, the water saturation temperature is correspondingly reduced. Therefore, at cross-section Bi, the physical state of the flowing water may be located in the transition zone, which is a mixture of water and steam. This phenomenon is shown as Point A and Point Bi in the Pressure- Temperature Phase Equilibrium Diagram in FIG. 11. When plotting Point A and Point Bi in the Pressure-Enthalpy Phase Equilibrium diagram, they may typically be located as shown in FIG. 12. As the energy loss from Point A to Bi is very small, the total enthalpy of the mixture at Point Bi is only slightly lower than that of the undersaturated water at Point A, that is, H_B1 < H_A. More importantly, a certain amount of steam may be flashed out from the water phase in this situation. Because the steam mass quality (or dryness) may be any value between 0% and 100% in the transition zone, the steam mass quality of the mixed water and steam (that is, a wet steam) mainly depends on the enthalpy of the incoming undersaturated water at Point A and pressure and temperature at Point Bi.

In the throat section 134, the physical state and carried enthalpy of the mixed water and steam only have minor changes, which leads to TBI ~ TB2 as shown in FIG. 11 and HBI ~ HB2 as exemplified in FIG. 12. When the mixed water and steam (wet steam) flow through the divergent section 136 from the cross-section B2 to cross-section C in a suitable divergent angle corresponding to the specific viscosity of the fluid, the mixed water and steam will expand their volume while conforming to the wall of the divergent section 136. In this expansion process, the mixed water and steam conduct work to the surrounding environment of the bore 130, as shown in Equation (2) below. Meanwhile, the carried total enthalpy, temperature, and/or pressure may decrease in terms of the energy balance theory from the first law of thermodynamics.

wherein W represents the work conducted by the mixed water and steam, P represents the pressure of the mixed water and steam, VB2 represents the volume of the mixed water and steam at crosssection B2, and Vc represents the volume of the mixed water and steam at cross-section C. The pressure at cross-section C can be smaller, equal to, or higher than that at cross-section B2.

For example, in FIG. 11, the temperature of Point C may be lower than that of Point B2 in comparison to the process occurred in convergent section 132 from Point A to Point Bi, where the temperature of Point Bi is only slightly lower or very close to that of Point A. Correspondingly, in FIG. 12, the enthalpy of Point C may be substantially lower than that of Point B2 in comparison to the process occurred in the convergent section 132 from Point A to Point Bi. In the divergent zone 134, the mixture may flash out more steam from water at a relatively lower pressure and temperature conditions. As shown in FIG. 12, steam mass quality at Point C is higher than that at Point B2. In the inflow-control apparatus 100 of the present disclosure, it may increase the steam mass quality at the interior end to near, at, or above (for example, doubling) that at the exterior end, which is equivalent to a similar rate of increase of the steam volume fraction under typical SAGD operating conditions.

Thus, when flowing through the central bore 130 of the inflow-control apparatus 100 disclosed herein, undersaturated or saturated unwanted fluid (for example, water or steam) may experience significant pressure drop and flash out a substantial amount of steam, or experience a substantial expansion of its volume thereby mitigating unwanted fluid (for example, water or steam) being produced to surface.

FIG. 13 shows a plot of pressure drop to mass flow rate for a particular embodiment of the inflow-control apparatus 100. At the same mass flow rate, the pressure drop of the flashed water across the apparatus 100 will be higher than that of hypothetical water which has the same properties as pure liquid water at the same temperature and pressure condition but without flashing capabilities (that is, “the hypothetical liquid”). In an embodiment, at the same mass flow rate, the pressure drop of the flashed water across the inflow-control apparatus 100 is at least about 20% higher than that of a heated heavy oil under typical SAGD or CSS downhole conditions. In an embodiment, the general stope of pressure drop to mass flow rate of the flashed water using the inflow-control apparatus 100 is equal to or greater than that of the pressure drop to mass flow rate of the hypothetical liquid.

As mentioned above, the inflow-control apparatus 100 of the present disclosure may provide an environment for flashed vapor from the water phase to conform to the wall of the divergent zone 136. An exemplary model image of this conformance is shown in FIG. 14A. The conformance to the wall of the divergent zone 136 indicates that the flashed steam dominates the whole flow. In contrast, FIG. 14B shows the mainstream of flashed vapor from the water phase detaching from the wall in an inflow-control apparatus that does not have the features of the inflow-control apparatus of the present disclosure, indicative that the steam volume fraction is decreasing, flattening, or not increasing as significantly as that created from the present disclosure.

Experimental tests have been performed on an inflow-control apparatus 100 of an exemplary geometry (denoted “Geometry 5” hereinafter), wherein the ID De of the convergent section 132 and the ID DT of the throat section 134 are in a ratio of 1.67:1, and the ID DD of the divergent section 136 and the ID DT of the throat section 134 are also in a ratio of 1.67: 1. In the experimental tests, the mass flow rate is targeted at 0. 15 kg/s, the temperature at the inlet 120 of the inflow-control apparatus 100 is 220 °C, the pressure at the inlet 120 of the inflowcontrol apparatus 100 is pre-calculated according to different subcool conditions and the specific steam quality shown in Table 1 below. The pressure at the outlet 136B of the inflow-control apparatus 100 is adjusted to reach the targeted mass flow rate of 0.15 kg/s. The unwanted fluids, for example, the undersaturated or saturated water and steam/vapor, are chosen as the testing fluid in the experimental tests.

Table 1 Testing Conditions for Geometry 5

FIG. 15A shows the pressure differences between the inlet 120 and outlet 136B of the inflow-control apparatus 100 under different testing conditions shown in Table 1. As can be seen, the pressure drop (Delta P) between the inlet 120 and outlet 136B of the inflow-control apparatus 100 increases as the temperature at the inlet 120 approaches the saturation temperature of water at the specific inlet pressure of the inflow-control apparatus 100. The Delta P increases more significantly as a certain amount of steam vapor, such as 1% and 2% steam quality (mass fraction), is injected with the saturated water. When the steam quality is increased to 2.2% mass fraction or higher, the injected fluid (saturated water and steam/vapor) is “choked”, which means that at higher than 2.2% steam quality, the targeted mass flow rate of the injected fluid, which is 0.15kg/s in this case, cannot be achieved regardless how much lower the outlet pressure of the inflow-control apparatus 100 is decreased thereto.

In a practical SAGD operation, the above-mentioned experimental performance of the inflow-control apparatus 100 may be achieved in the following situations.

1) At normal or sufficient subcool conditions, the pressure drop (Delta P) between the inlet 120 and outlet 136B of the inflow-control apparatus 100 may be relatively small when having a highly subcooled water (such as greater than or equal to 20 °C subcool) or hydrocarbon passing through the inflow-control apparatus 100. 2) As hot spots developing in certain locations along the horizontal wellbore due to reservoir heterogeneity or pressure loss through the wellbore, these hot spots may encounter a much lower subcool of the coming undersaturated or saturated water. In this case, the installed downhole inflow-control apparatus 100 may create larger pressure drops in these hot spots to inhibit the unwanted fluid while enhancing the production of the wanted fluid, for example, oil/hydrocarbon from other cold regions.

3) Some severe hot-spots may encounter the breakthrough of saturated water mixed with a certain amount of steam. In this case, the inflow-control apparatus 100 may yield a substantially high pressure drop to restrict the flow of the unwanted fluid. At the choke condition, the mass flow of the unwanted fluid reaches the upper limit or supercavitation condition of the inflowcontrol device regardless how much more drawdown pressure the downhole pump creates. In this case, by applying large drawdown pressure by downhole pumps, the oil production may be further enhanced from the cold regions of the reservoir while the inflow-control apparatuses 100 restrict the flow of the unwanted fluid from the hot spots.

FIG.15B shows the steam volume fraction at the inlet 120 and outlet 136B of the inflowcontrol apparatus 100. As shown, when the subcool temperature of the injected water is 5 °C or lower, the steam volume fraction (SVF) increases as the inlet temperature of the inflow-control apparatus 100 approaches the saturation temperature of the water at the specific inlet pressure. The SVF at the outlet 136B of the inflow-control apparatus 100 is much larger than that at the inlet 120 thereof when the injected water has a low subcool-temperature or contains saturated water mixed with a certain amount of steam. The difference between the inlet and outlet SVF becomes larger as steam quality increases in the injected fluid. The results show that flashing or cavitation and/or expansion has occurred at the testing conditions to create the additional pressure drop when the unwanted fluid passes through the inflow-control apparatus 100.

In above embodiments, the inflow-control apparatuses 100 are coupled to the base pipe 14 via suitable connections. In one embodiment, the inflow-control apparatuses 100 are integrated with the base pipe 14. In another embodiment, the inflow-control apparatuses 100 are manufactured on the base pipe 14. More specifically, the base pipe 14 in this embodiment may comprise a plurality of ports with the inner wall of each port being formed with the convergent section 132, the throat section 134, and the divergent section 136 as described above.

In an embodiment wherein the base pipe 14 comprises a plurality of ports 120 and thus a plurality of inflow-control apparatuses 100, the plurality of inflow-control apparatuses 100 may be spaced apart around the circumference of the base pipe 14. In another embodiment, the plurality of inflow-control apparatuses 100 may be longitudinally distributed on the sidewall of the base pipe 14. In yet another embodiment, the plurality of inflow-control apparatuses 100 may be positioned around the circumference of the base pipe 14 and longitudinally distributed on the sidewall of the base pipe 14. In an embodiment, the spacing is chosen to more evenly distribute wellbore pressure. The spacing may be of any suitable distance along the longitudinal direction of the base pipe 14 and may be uniform spacing or non-uniform spacing as needed.

FIG. 16 shows an inflow-control apparatus 100 according to an alternative embodiment of this disclosure, which is similar to the inflow-control apparatus 100 shown in FIGs. 3 A to 3C except that the inflow-control apparatus 100 in this embodiment does not comprise any inlet on the side of the head portion. Rather, the inflow-control apparatus 100 in this embodiment comprises an inlet 120 on the end wall on the exterior side thereof.

FIG. 17 shows an inflow-control apparatus 100 according to an alternative embodiment of this disclosure, which is similar to the inflow-control apparatus 100 shown in FIG. 16 except that the inflow-control apparatus 100 in this embodiment has an uniform OD.

FIG. 18 shows the base pipe 14 with the solids filter 220 and the housing 232 enclosing therein a plurality of inflow-control apparatuses 100 shown in FIG. 17. The base pipe 14 is similar to that shown in FIGs. 5C and 5D, except that the ports 210 are at an angle (that is, unperpendicular) to the sidewall 212, and the inflow-control apparatuses 100 are received in the ports 210 also at an angle to the sidewall 212 for reducing the profile of the inflow-control apparatuses 100 on the base pipe 14.

Although embodiments have been described above with reference to the accompanying drawings, those of skill in the art will appreciate that variations and modifications may be made without departing from the scope thereof as defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for coupling to a port on a sidewall of a base pipe in a wellbore, the apparatus comprising: a body having an exterior end and an interior end; at least one inlet positioned on or about the exterior end of the body for receiving a fluid, the fluid comprising water in at least one of a liquid phase and a gas phase; an outlet on or about the interior end of the body; and a bore extending within the body and in fluid communication with the at least one inlet and the outlet, the bore comprising: a first section in fluid communication with the at least one inlet for decreasing a pressure of the fluid by increasing a velocity thereof; a second section coupled to the first section for causing a volume of steam to at least restrict a flow of the fluid in the bore; and a third section coupled to the second section and in fluid communication with the outlet for causing more volume of steam to at least further restrict the flow of the fluid in the bore.

2. The apparatus of claim 1, wherein the third section is coupled to the second section and is in fluid communication with the outlet for further decreasing the pressure or expanding the volume of the fluid for causing the more volume of steam to at least further restrict the flow of the fluid in the bore.

3. The apparatus of claim 1 or 2, wherein the apparatus is configured for providing a steam volume fraction of at least 0.2 at the outlet with a mass flow rate within a predefined range.

4. An apparatus comprising: a body having an exterior end and an interior end; at least one inlet positioned about the exterior end of the body; an outlet on or about the interior end of the body; and a bore extending within the body and in fluid communication with the at least one inlet and the outlet, the bore comprising:

23 a first section having a first end in fluid communication with the at least one inlet, a second end, and a first length defined therebetween, the first section having a first inner diameter (ID) continuously reducing from the first end to the second end with a maximum first ID at the first end; a second section extending from the second end to a third end with a second length defined therebetween, the second section having a uniform second ID equal to the first ID of the first section at the second end; and a third section extending from the third end to a fourth end in fluid communication with the outlet, the third section having a third length defined between the third end and the fourth end, and the third section having a third ID continuously increasing from the third end to the fourth end with a maximum third ID at the fourth end.

5. The apparatus of claim 4, wherein the third length is greater than the first length.

6. The apparatus of claim 4 or 5, wherein the maximum third ID is greater than the second

ID.

7. The apparatus of claim 4, wherein the first ID of the first section is linearly reduced from the first end to the second end.

8. The apparatus of any one of claims 4 to 7, wherein the third ID of the third section is linearly increased from the third end to the fourth end.

9. The apparatus of any one of claims 4 to 8, wherein the maximum first ID and the second ID are in a ratio between 3.0: 1 and 1.2: 1.

10. The apparatus of any one of claims 4 to 9, wherein the maximum third ID and the second

ID are in a ratio of between 2.5: 1 and 1.2: 1.

11. The apparatus of any one of claims 4 to 10, wherein the third length and the first length are in a ratio of at least 2: 1.

12. The apparatus of any one of claims 4 to 11, wherein the at least one inlet is on a sidewall of the body adjacent the exterior end thereof or on an end-wall of the body at the exterior end thereof.

13. The apparatus of any one of claims 4 to 12, wherein the apparatus is configured for providing a steam volume fraction of at least 0.2 at the fourth end with a mass flow rate within a predefined range.

14. A downhole system comprising: a base pipe having one or more ports on a sidewall thereof, each of the one or more ports receiving therein an apparatus of any one of claims 1 to 13 for directing the fluid into the base pipe; and at least one filter for filtering solids in the fluid and directing the fluid to the apparatus.

15. A method for restricting water in a fluid entering a base pipe in a wellbore, the method comprising:

(i) directing the fluid from a hydrocarbon reservoir into a channel towards the base pipe;

(ii) decreasing a pressure of the fluid in the channel by increasing a velocity thereof;

(iii) causing a volume of steam to at least restrict a flow of the fluid in the channel; and

(iv) causing more volume of steam to at least further restrict the flow of the fluid in the channel.

16. The method of claim 15, wherein said causing the more volume of steam to at least further restrict the flow of the fluid in the channel comprises: further decreasing the pressure or expanding the volume of the fluid for causing the more volume of steam to at least further restrict the flow of the fluid in the channel. having a third ID continuously increasing from the third end to the fourth end with a maximum third ID at the fourth end.