Tapered Fluidic Diode For Use As An Autonomous Inflow Control Device AICD

TECHNICAL FIELD

The present disclosure generally relates to systems and methods for regulating fluid flow, particularly within a subterranean formation, and, more specifically, to rotational motion-inducing variable flow resistance systems. These variable flow resistance systems can autonomously vary a resistance to flow of a fluid through the systems based on one or more characteristics of the fluid.

BACKGROUND

It can be beneficial to regulate the flow of formation fluids within a wellbore penetrating a subterranean formation. A variety of reasons or purposes can necessitate such regulation including, for example, prevention of water and/or gas coning, minimizing water and/or gas production, minimizing sand production, maximizing oil production, balancing production from various subterranean zones, equalizing pressure among various subterranean zones, and/or the like.

Likewise, it can also be beneficial to regulate the flow of injection fluids such as, for example, water, steam or gas, within a wellbore penetrating a subterranean formation. Regulation of the flow of injection fluids can be particularly useful, for example, to control the distribution of the injection fluid within various subterranean zones and/or to prevent the introduction of injection fluid into currently producing zones.

Therefore, it will be readily appreciated that improvements in the arts of fluid inflow control devices are continually needed.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure. In the drawings, like reference numbers may indicate identical or functionally similar elements. Embodiments are described in detail hereinafter with reference to the accompanying figures, in which:

FIG. 1 is a representative partial cross-sectional view of a wellbore in which the variable flow resistance systems of the present disclosure can be used, according to one or more example embodiments;

FIGS. 2A-2B are representative partial cross-sectional views of a well screen in which the variable flow resistance systems of the present disclosure can be used, according to one or more example embodiments;

FIGS. 3A-3C are representative partial cross-sectional views of an inflow control portion of the well screen in which the variable flow resistance systems of the present disclosure can be used, according to one or more example embodiments;

FIG. 4 is a representative unrolled view of a base pipe of the well screen shown in FIGS. 2A-2B;

FIGS. 5A-12 are representative cross-sectional side views of example configurations of the variable flow resistance system; and

FIGS. 13A-15B are representative cross-sectional top views of example configurations of the variable flow resistance system.

DETAILED DESCRIPTION OF THE DISCLOSURE

The disclosure may repeat reference numerals and/or letters in the various examples or Figures. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as beneath, below, lower, above, upper, uphole, downhole, upstream, downstream, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure, the uphole direction being toward the surface of the wellbore, the downhole direction being toward the toe of the wellbore. Unless otherwise stated, the spatially relative terms are intended to encompass different orientations of the apparatus in use or operation in addition to the orientation depicted in the Figures. For example, if an apparatus in the Figures is turned over, elements described as being “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Moreover even though a Figure may depict a horizontal wellbore or a vertical wellbore, unless indicated otherwise, it should be understood by those skilled in the art that the apparatus according to the present disclosure is equally well suited for use in wellbores having other orientations including vertical wellbores, slanted wellbores, multilateral wellbores or the like. Likewise, unless otherwise noted, even though a Figure may depict an offshore operation, it should be understood by those skilled in the art that the method and/or system according to the present disclosure is equally well suited for use in onshore operations and vice-versa. Further, unless otherwise noted, even though a Figure may depict a cased hole, it should be understood by those skilled in the art that the method and/or system according to the present disclosure is equally well suited for use in open hole operations.

As used herein, the words “comprise,” “have,” “include,” and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods also can “consist essentially of” or “consist of” the various components and steps. It should also be understood that, as used herein, “first,” “second,” and “third,” are assigned arbitrarily and are merely intended to differentiate between two or more objects, etc., as the case may be, and does not indicate any sequence. Furthermore, it is to be understood that the mere use of the word “first” does not require that there be any “second,” and the mere use of the word “second” does not require that there be any “first” or “third,” etc.

The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

Generally, this disclosure is directed to a system for autonomously regulating fluid flow, particularly within a subterranean formation, and, more specifically, to rotational motion-inducing variable flow resistance systems. A system can provide autonomous flow control of a fluid flowing between a wellbore to an interior of a tubing string by using the variable flow resistance system. The system can include a body, with a chamber that can be configured to induce rotational flow in a fluid that flows through the chamber. The chamber can include an inlet for fluid entering the chamber and an outlet for fluid exiting the chamber. A cross-sectional area of the chamber can be reduced along a central axis of the chamber toward the outlet, with the cross-sectional area being perpendicular to a central axis. Additionally, a well screen assembly may utilize one or more of the variable flow resistance systems to provide a determined flow resistance and/or flow rate through the screen assembly.

As discussed above, variable flow resistance systems that induce rotational motion within a fluid typically can incorporate a fluid exit hole at the bottom of a chamber, where the location of the exit hole facilitates vortex-like rotational motion of the fluid. However, this location of the exit hole can make series connections between chambers problematic if a greater degree of fluid flow regulation is needed than can be provided by a single chamber.

The present disclosure describes variable flow resistance systems that have chambers both with and without a fluid exit hole extending through the bottom of the chamber. The embodiments that do not have a fluid exit hole extending through the bottom of the chamber, have a fluid outlet located in a sidewall of the chamber. The primary advantage of chambers with sidewall exits is that they can be efficiently coupled together in series in a variable flow resistance system (e.g., in a substantially horizontal arrangement) without having to conduct excessive vertical movement of the fluid during transport between adjacent chambers. A substantially horizontal arrangement offered by the sidewall exit chambers can be particularly efficient in terms of space utilization, such that they can be readily used in confined regions, such as within a wellbore penetrating a subterranean formation. Furthermore, the opportunity to connect multiple chambers in series in a variable flow resistance system can achieve greater fluid flow regulation than is attainable using a single chamber alone. If a series configuration is not needed (e.g. one chamber can provide sufficient flow resistance), then the bottom hole exit can be used to advantage.

In some embodiments, variable flow resistance systems described herein can comprise a chamber configured to induce rotational motion of a fluid flowing therethrough, a fluid inlet coupled to the chamber; and a fluid outlet coupled to the chamber that allows the fluid to exit through a sidewall or a bottom of the chamber.

In some embodiments, multiple chambers can be connected in series with one another in a variable flow resistance system. In some embodiments, variable flow resistance systems described herein can comprise a plurality of chambers that are connected in series fluid communication with one another, where each chamber has a fluid inlet and a fluid outlet coupled thereto, and at least some of the chambers are configured to induce rotational motion of a fluid flowing therethrough, and the fluid outlets of at least some of the chambers are configured to allow the fluid to exit through a sidewall of the chamber, with other fluid outlets configured to allow the fluid to exit through a bottom of the chamber.

When multiple chambers are connected in series in a variable flow resistance system, the chambers can all be the same in some embodiments, or at least some of the chambers can be different in other embodiments. In some embodiments, all of the chambers can have a fluid outlet that allows a fluid to exit through a sidewall of the chamber. In other embodiments, chambers having a fluid outlet that allows a fluid to exit through a sidewall of the chamber can be used in combination with chambers that have a fluid outlet exiting through the bottom of the chamber. The choice of a particular combination of chambers may be dictated by operational needs that will be evident to one having ordinary skill in the art.

As used herein, the term “chamber” refers to an enclosed space having at least one inlet and at least one outlet. As used herein, use of the term “chamber” makes no implication regarding the shape and/or dimensions of the chamber unless otherwise specified.

As used herein, the term “sidewall” refers to any surface of chamber extending between the chamber's top exterior surface and the chamber's bottom exterior surface. As used herein, the term “exterior surface” refers to the outside surface of a chamber that is not in contact with a fluid passing through the chamber. As used herein, the term “rotational motion” refers to motion that occurs around an axis.

In various embodiments, the variable flow resistance systems of the present disclosure can be used in a wellbore penetrating a subterranean formation. FIG. 1 shows a partial cross-sectional schematic of the wellbore 12 in which the variable flow resistance systems 25 of the present disclosure can be used. As shown in FIG. 1, well system 10 contains wellbore 12 having a generally vertical uncased section 14, extending from cased section 16, and a generally horizontal uncased section 18 extending through subterranean formation 20. Wellbore pipe 22 extends through wellbore 12, where wellbore pipe 22 can be any fluid conduit that allows fluids to be transported to and from wellbore 12. In some embodiments, wellbore pipe 22 can be a tubular string such as a production tubing string.

Multiple well screens 24, each in fluid flow communication with variable flow resistance systems 25, can be connected to wellbore pipe 22. Packers 26 can seal an annulus 28 defined by wellbore pipe 22 and the interior surface of horizontal uncased section 18. Packers 26 can provide zonal isolation of various subterranean zones penetrated by wellbore pipe 22, thereby allowing fluids 30 to be produced from or introduced into some or all of the zones of subterranean formation 20. Well screens 24 can filter fluids 30 as they move toward the interior of wellbore pipe 22. Each variable flow resistance system 25 can regulate access of fluids 30 to the interior of wellbore pipe 22 and/or restrict the flow of certain types of fluids 30 based upon certain characteristics or physical properties thereof.

It should be understood that the variable flow resistance systems described herein are not limited to the implementation displayed in FIG. 1, which has been presented merely for purposes of illustration and not limitation. For example, the type of wellbore 12 in which the present variable flow resistance systems 25 can be used is not particularly limited, and it is not necessary that wellbore 12 contain either vertical uncased section 14 or horizontal uncased section 18. Furthermore, any section of wellbore 12 can be cased or uncased, and wellbore pipe 22 can be placed in any cased or uncased wellbore section.

Furthermore, it is not required that fluids 30 are solely produced from subterranean formation 20, since fluids can be injected into subterranean formation 20 and produced therefrom in some embodiments. In addition, the various elements coupled to wellbore pipe 22 that are presented in FIG. 1 are all optional, and each may not necessarily be used in each subterranean zone, if at all. In some embodiments, however, the various elements coupled to wellbore pipe 22 can be duplicated in each subterranean zone. Still further, zonal isolation using packers 26 need not necessarily be performed, or other types of zonal isolation techniques familiar to one having ordinary skill in the art can be used.

These variable flow resistance systems 25 can restrict the passage of some fluids more than others based upon one or more physical property differences between the fluids. Illustrative physical properties of a fluid that can determine its rate of passage through a variable flow resistance system can include, for example, viscosity, velocity and density. Depending on the type, composition and physical properties of a fluid or fluid mixture whose passage is to be restricted, variable flow resistance systems 25 can be configured such that higher ratios of a desired fluid to an undesired fluid can flow through a flow pathway containing the variable flow resistance system 25.

Rotational motion can be particularly effective for variably restricting fluid flow within a variable flow resistance system. In variable flow resistance systems 25 capable of inducing rotational motion, a fluid composition may enter a chamber 50 within the variable flow resistance system 25 in such a way that an undesired component of the fluid composition undergoes greater rotational motion than does a desired component of the fluid composition. As a result, the undesired component traverses a longer flow pathway than does the desired component, and the undesired component's residence time within the variable flow resistance system 25 can be increased. The variable flow resistance system can be configured such that fluid exiting the variable flow resistance system 25 is discharged through one or more holes in the bottom and/or sides of the chamber 50. The fluid 30 can be a fluid composition that contains both desired and undesired components, or the fluid 30 can be either a desired or undesired fluid, without containing components of the other type fluid. The viscosity, velocity and/or density of the fluid 30 (or components in the fluid 30) can be used by the variable flow resistance system 25 (may also be known as Autonomous Inflow Control Devices AICDs) to autonomously restrict undesired fluids or fluid components more than desired fluids or fluid components without moving parts in the variable flow resistance system 25 (other than the fluid 30 or material contained within the fluid 30 as it flows through the system 25).

In various non-limiting embodiments, the present variable flow resistance systems 25 can be used to prevent water coning or gas coning from subterranean formation 20. In some embodiments, the present variable flow resistance systems 25 can be used to equalize pressure and balance production between heel 13 and toe 11 of wellbore 12. In other embodiments, the present variable flow resistance systems 25 can be used to minimize the production of undesired fluids and to maximize the production of desired fluids. It should also be understood that the present variable flow resistance systems 25 can be used for injection operations as well to accomplish similar advantages to those noted above.

Whether a fluid is a desired fluid or an undesired fluid will usually be determined by the nature of the subterranean operation being conducted. For example, if the goal of a subterranean operation is to produce oil but not natural gas or water, the oil can be considered a desired fluid and the natural gas and water can be considered undesired fluids. In other cases, natural gas can be a desired fluid, and water can be an undesired fluid. It should be noted that at downhole temperatures and pressures, natural gas can be at least partially liquefied, and in the disclosure presented herein, the term “natural gas” or more simply “gas” will refer to a hydrocarbon gas (e.g., methane) that is ordinarily in the gas phase at atmospheric pressure and room temperature.

In general, the variable flow resistance systems 25 described herein can be used in any subterranean operation in which there is a need to regulate the flow of fluids to or from the interior of a wellbore pipe 22. Reasons why one of ordinary skill in the art might wish to regulate the flow of fluids can include, for example, to prevent or minimize water and/or gas coning, to prevent or minimize water and/or gas production, to prevent or minimize sand production, to maximize oil production, to better balance production from various subterranean zones, to better equalize pressure among various subterranean zones, and/or the like.

In particular, the variable flow resistance systems 25 described herein can be used during production or injection operations within a subterranean formation in some embodiments. In some embodiments, methods for using the variable flow resistance systems 25 of the present disclosure can comprise: installing a wellbore pipe 22 in an uncompleted wellbore 12, wherein the wellbore pipe 22 comprises at least one variable flow resistance system 25 that is in fluid communication with the interior of the wellbore pipe 22. In such embodiments, each variable flow resistance system 25 can comprise a plurality of chambers 50 that are connected in series fluid communication with one another, where each chamber 50 has a fluid inlet and a fluid outlet coupled thereto, and at least some of the chambers 50 are configured to induce rotational motion of a fluid flowing therethrough and the fluid outlets of at least some of the chambers 50 are configured to allow the fluid to exit through a sidewall and/or a bottom of the chamber 50.

In some embodiments, the methods can further comprise allowing a formation fluid 30 to flow through at least some of the variable flow resistance systems 25 and into the interior of the wellbore pipe 22. In some embodiments, the methods can further comprise producing the formation fluid 30 from the wellbore pipe 22.

In some embodiments, the present variable flow resistance systems 25 can be used in injection operations. For example, the variable flow resistance systems 25 can be used to control the introduction of various types of treatment fluids into a subterranean formation. In injection operations, fluids that can be injected can include, for example, steam, liquefied gases and water. The variable flow resistance systems 25 can be used to compensate for heel-to-toe pressure variations or permeability variations within the subterranean formation.

In some embodiments, the wellbore 12 can comprise a horizontal wellbore. In other embodiments, the wellbore 12 can comprise a vertical wellbore. In some embodiments, the wellbore can comprise a plurality of intervals, where there is at least one variable flow resistance system 25 located within each interval.

The present variable flow resistance systems 25 can comprise at least one chamber 50 that has a fluid outlet 82. Some illustrative variable flow resistance systems 25 are described in more detail hereinbelow with reference to the drawings. Other implementations, orientations, arrangements and combinations of the features described hereinbelow and presented in the drawings are possible, and given the benefit of the present disclosure, it will be within the capabilities of one having ordinary skill in the art to combine these features. Additionally, all features of the variable flow resistance systems 25 disclosed in some embodiments can be used in the other embodiments disclosed herein.

In some embodiments, the chambers 50 of the present disclosure can contain various flow-inducing structures 90, 92 that induce rotational motion to a fluid flowing therethrough. In some embodiments, the flow-inducing structures can be formed as vanes or recesses on or within the interior surfaces 76, 77, 78, 79 (FIGS. 5A-12) of the chamber 50. Any number of flow-inducing and/or flow-restricting structures can be used within the chambers to impart a desired degree of flow resistance to a fluid 30 passing therethrough.

Furthermore, in some embodiments, the design of the chambers 50 can be such that only fluids with certain physical properties can undergo a desired degree of rotational motion within the chamber 50. That is, in some embodiments, the design of the chambers 50 can be configured to take advantage of a fluid's physical properties such that at least one physical property dictates the fluid's rate of passage through the chamber. Specifically, fluids having certain physical properties (e.g., viscosity, velocity and/or density) can be induced to undergo greater rotational motion when passing through the chamber, thereby increasing their transit time relative to fluids lacking that physical property. For example, in some embodiments, the chamber 50 can be configured to induce increasing rotational motion of a fluid with decreasing fluid viscosity. Consequently, in such embodiments, a fluid having a greater viscosity (e.g., oil) can undergo less rotational motion when passing through the chamber than does a fluid having a lower viscosity (e.g., gas or water), and the high viscosity fluid can have its transit time through a flow pathway affected to a much lesser degree than does the low viscosity fluid.

Various types of fluid outlets 82 are compatible with the variable flow resistance systems 25 described herein. In some embodiments, the fluid outlet 82 can comprise a channel within the chamber 50 that extends from the top or bottom interior surface of the chamber 50 and a sidewall and/or bottom of the chamber. In some embodiments, the fluid outlet 82 can comprise a cone-shaped fluid outlet 82, a hole in the sidewall and/or bottom of the chamber 50, at least one groove or slit within the sidewall of the chamber. Other types of fluid outlets 82 can include, for example, curved pathways, helical pathways, pathways with directional changes, and segmented pathways with diameter variations. Combinations of different fluid outlet 82 types are also possible.

FIG. 2A shows a partial cross-sectional view of a well screen assembly 24 that can be used in the well system 10. The screen assembly 24 can include many different configurations of ends 44, 46, filter layer (e.g. wire wraps 42), base pipe 40, and variable flow resistance systems 25, as well as more conventional inflow control devices. In the example shown in FIG. 2A, triangle-cross-section wire 42 can be wrapped around the base pipe 40 and supported away from the base pipe 40 by supports (not shown), thereby forming a filter layer 51 consisting of spaces 53 between adjacent wire 42 sections and a drainage layer 52 defined by the space between the wires 42 and the exterior of the base pipe 40. Fluid 30 can flow through the spaces 53 in the filter layer 51, through the drainage layer 52 (e.g. fluid flow 32), and through one or more variable flow resistance systems 25 to join the fluid flow 36 in the flow passage 48 of the screen assembly 24. The end 44 can form an annular region 43 between the base pipe 40 and the end 44 that can contain one or more variable flow resistance systems 25 for variably restricting the flow of fluid through the screen assembly 24. Fluid flow 32 from the drainage layer 52 can enter a variable flow resistance system 25 as fluid flow 33 through an inlet 80 (see FIG. 3A), experience a variable rotational flow 35, and exit through an outlet 82 (see FIG. 3A) as fluid flow 34, which can join the fluid flow 36 in flow passage 48. The variable rotational flow 35 can change depending on the characteristics of the fluid 30 flowing through the screen assembly 24, thereby providing variations in a restriction to flow through the variable flow resistance (VFR) system 25. Increased backpressure of the fluid flow 33 would increase restriction to flow through the system 25, and a decreased backpressure of the fluid flow 33 would decrease restriction to flow through the system 25.

The screen assembly shown in FIG. 2B is very similar to FIG. 2A, except that multiple variable flow resistance systems 25 are shown arranged in series fluid communication with each other in the annular region 43, with the first VFR system 25 receiving fluid flow 33 at its input and outputting fluid flow 34 through an outlet 82 in a sidewall of the chamber 50 of the VFR system 25. Fluid flow 34 from the first VFR system 25 outlet 82 can flow to an inlet 80 of a second VFR system 25 via fluid flow 38 and exit the second VFR system 25 as fluid flow 34. The fluid 30 flowing through each of the VFR systems 25 may experience rotational flow 35 in each of the chambers 50, thereby producing a larger resistance to flow of the fluid 30.

FIGS. 3A-3C show various configurations of the end 44 and annular region 43 of the screen assembly 24. FIG. 3A shows a portion of the base pipe 40 adjacent the end 44 with openings 56. It should be understood that multiple openings 56 can be positioned circumferentially around the base pipe 40, yet only two are shown in the example of FIG. 3A. The screen assembly 24 can be configured at the surface to provide the desired amount of VFR systems 25 installed in the available openings 56, with any remaining openings not receiving a VFR system 25 to be plugged by a plug 54, thereby forcing fluid flowing through the screen assembly 24 to flow through the VFR systems 25. The end 44 may also include an annular support 45 with multiple openings to allow fluid flow 32 to enter the annular region 43 of the end 44 while supporting the portion of the end 44 that is adjacent to the wire wraps 42. It should be understood that this support 45 is not required, since the end 44 could be supported by VFR systems, other support structures, or may not require additional support at all.

The single VFR system 25 shown in FIG. 3A has a single inlet 80 that receives fluid flow 33, a single outlet 82 that outputs fluid flow 34 into the flow passage 48 where it can join fluid flow 36. The chamber 50 can include interior surfaces 76, 77, and 78 as well as an interior surface 79 of the outlet 82. As fluid 30 enters the VFR system 25 as fluid flow 33, it interacts with the surfaces 76, 77 which can urge the fluid 30 to flow rotationally around the axis 60 of the VFR system 25, which in this configuration is in line with axis 62 of the chamber 50. As stated above, if the fluid 30 is undesired fluid, then the rotational flow 35 can be increased, thereby increasing flow restriction through the VFR system 25, and reducing flow through the screen assembly 24. However, if the fluid 30 is a desired fluid, then the rotational flow 35 can be minimized, thereby decreasing flow restriction through the VFR system 25, and increasing flow through the screen assembly 24. In this example the surface 77 is a cylindrical surface positioned at the top of the chamber 50 with the surface 76 being conically shaped. The inlet 80 can direct the fluid flow 33 toward a surface 76, 77 and slightly away from the axis 60, 62. It should be understood that these surfaces 76, 77 can be smooth, rough, grooved, and/or slotted, and can contain recesses and/or protrusions to either encourage or discourage rotational flow 35 in the fluid 30 that passes through the VFR system 25.

The end 44 and annular region 43 of the screen assembly 24 shown in FIG. 3B is very similar to that shown in FIG. 3A, except that the plug 56 is replaced with a second VFR system 25. The first VFR system 25 can receive fluid 30 from the drainage layer 52 via fluid flow 32 and 33. Rotational flow 35 about axis 60 may be induced in the fluid 30 as it travels through the first VFR system 25 and exits the outlet 82 positioned in a sidewall of the first VFR system 25. As fluid flow 34 exits the first VFR system 25, it is directed to the input 80 of the second VFR system 25 by fluid flow 38 which can be constrained in a tube connecting the two VFR systems 25, or constrained by a partition in the annular region 43 that forces fluid flow 38 to enter the second VFR system 25 as fluid flow 33. Rotational flow 35 about axis 60 may again be induced in the fluid 30 as it travels through the second VFR system 25 and exits into the flow passage 48 from the outlet 82 positioned in a sidewall of the second VFR system 25. This configuration can provide additional flow restriction to fluid 30 flowing through the screen assembly 24 than can be provided by a single VFR system 25.

However, if less flow restriction and more flow rate is desired, then multiple single (i.e. not-cascaded) VFR systems 25 can be installed in the openings 56 in the base pipe 40 to allow more parallel paths for the fluid 30 to flow through the screen assembly. FIG. 3C shows such an example configuration. FIG. 3C is very similar to FIGS. 3A and 3B, except that VFR systems 25 are installed in the desired number of openings 56 (only two shown), with each VFR system 25 receiving fluid 30 from fluid flow 32 from the drainage layer 52, with a portion of the fluid flow 32 flowing around and/or over the first VFR system 25 to reach the second VFR system 25 in the annular region. Both VFR systems 25 shown in the cross-section can receive a portion of the fluid 30 as input fluid flow 33. Rotational flow 35 about axis 60 may be induced in the portion of the fluid 30 that travels through the each VFR system 25 and exits the outlet 82 positioned in a bottom of each VFR system 25. Fluid flow 34 from each VFR system 25 can enter the flow passage 48 and join fluid flow 36 that can flow to the surface.

FIG. 4 shows an example of a base pipe 40 of a screen assembly unrolled to illustrate possible configurations of multiple openings 56 in the base pipe. These openings 56 can be positioned within the annular region 43 portion of the base pipe, which, in this example, is the region 59 that is between the region 57 for attaching the end 44 to the base pipe 40, and the region 58 where the wire wraps 42 of the filter layer may be positioned in the screen assembly 24. The screen assembly 24 can be configured at the surface to provide a desired flow rate and/or flow restriction to fluid 30 flowing through the screen assembly 24. A portion of the openings 56 can have VFR systems 25 installed in them with the remaining openings (if there are any) plugged with plug 54. Additionally, the VFR systems 25 can be configured in various parallel and series arrangement to further tailor the desired flow rate and/or flow restriction. The arrows for fluid flow 32 and 38 show possible flow paths the fluid 30 may take with various configurations. It should be understood that many configurations of the VFR systems 25 can be used in keeping with the principles of this disclosure.

FIGS. 5A-12 illustrate various embodiments of the VFR system 25 that can be utilized for variable flow resistance applications, such as screen assemblies 24, with each feature in each of the embodiments useable in each of the other embodiments in combination with or in replacement of various other features. FIG. 5A shows a VFR system 25 with an axis 60 of a body 68 of the VFR system 25. Fluid 30 enters the chamber 50 through inlet 80 as fluid flow 33. If the fluid is a desired fluid, then rotational flow 35 about axis 60 is reduced and a backpressure applied to the fluid flow 33 is also reduced, thereby allowing increased fluid flow 34 to exit the chamber 50 via the outlet 82. If an undesired fluid (such as gas or water, when hydrocarbon liquid are being produced) enters the chamber 50 through inlet 80 as fluid flow 33, then rotational flow 35 is increased in the chamber 50, thereby increasing backpressure applied to the fluid flow 33 and reducing fluid flow through the VFR system 25.

In some embodiments, the location of the fluid inlet 80 can be such that rotational motion is induced in the fluid 30 as it enters the chamber 50. For example, the chamber 50 and fluid inlet 80 can be configured such that fluid 30 entering the chamber 50 is introduced along a curved sidewall (e.g. 76, 77 in some embodiments) of the chamber 50, which can set the fluid 30 into rotational motion within the chamber. Furthermore, there are no limitations regarding the separation of the fluid inlet 80 and the fluid outlet 82 from one another. Generally, at least some degree of separation can be maintained between the fluid inlet 80 and the fluid outlet 82 so that an undesired fluid does not enter the fluid outlet 82 without first undergoing rotational motion, but this is not required.

FIG. 5A shows an inlet 80, and outlet 82, and a conical-shaped chamber 50. The chamber can include a cylindrical-shaped interior surface 77 and frusto-conically-shaped interior surface 76 for inducing rotational flow 35 of the fluid 30 as it flows through the VFR system 25. The rotational fluid flow 35 generally rotates about an axis 60 that can be a central axis 60 of the VFR system 25, as well as a central axis 62 of the chamber 50. Please note that it is not a requirement for the axis 60 and the axis 62 to be aligned as seen in FIG. 5A. These axes 60, 62 can be offset (i.e. spaced apart, but parallel) and/or angled relative to each other (see FIG. 9). The rotational fluid flow 35 can be increased or decreased depending upon the physical characteristics of the fluid 30 flowing though the VFR system 25, as described previously.

For purposes of discussion, please refer to FIGS. 13A and 13B which show a partial cross-sectional top view of the VFR system in FIG. 5A. FIG. 13A illustrates how the rotational fluid flow 35 can be affected when a desired fluid is flowing through the VFR system 25. When a desired fluid (e.g. oil in oil production) enters the chamber 50 through the inlet 80, the inlet 80 directs the fluid flow 33 away from the axis 60 and toward the surfaces 76, 77. The inlet 80 can be angled as shown in the FIGS. 13A and 13B, which can be somewhere between and including tangential to the interior surfaces 76, 77 and slightly directed away from the axis 60 when the fluid 30 enters the chamber 50 via fluid flow 33, thereby directing the fluid flow 33 into rotational fluid flow 35. With desired fluid, the rotational flow 35 can be minimized. Additionally, counter-rotational flow 35 (called “eddy currents”) can be induced in the flow of the desired fluid through the chamber 50, which tends to further reduce the rotational flow 35, thereby reducing travel time of the desirable fluid in the chamber 50 and increasing a flow rate through the VFR system 25 of the desired fluid.

FIG. 13B illustrates how the rotational fluid flow 35 can be affected when an undesired fluid is flowing through the VFR system 25. When the undesired fluid (e.g. water and/or gas in oil production) enters the chamber 50 through the inlet 80, the inlet 80 directs the fluid flow 33 away from the axis 60 and toward the surfaces 76, 77. Because of the physical properties of the undesired fluid, rotational fluid flow 35 is increased in the chamber 50 and travel time of the fluid through the chamber 50 is increased, thereby decreasing a flow rate of the undesired fluid through the VFR system 25.

Referring to FIGS. 5B and 5C, these embodiments of the VFR system 25 are very similar to FIG. 5A, except that the outlet 82 is configured differently for FIGS. 5B and 5C. FIG. 5C has an outlet with an axis 64 that is angled with angle A from the axis 60. This angle can be tailored to accommodate various exit angles of the fluid 30 as it exits the chamber 50 as fluid flow 34. FIG. 5C has an outlet with a curved exit path through which fluid 30 can exit the chamber 50 as fluid flow 34. It should be understood that the exit path from the chamber 50 for the fluid 30 can have many different configurations, as well as having multiple outlets 82.

The VFR system 25 in FIG. 6 is very similar to the VFR system 25 in FIG. 5A, except that the outlet 82 allows fluid 30 to exit from the VFR system 25 through a bottom surface 70 of the VFR system 25. FIGS. 7A and 7B illustrate how the rotational fluid flow 35 can be affected when flowing through the VFR system 25 of FIG. 6.

FIG. 7A illustrates how the rotational fluid flow 35 can be affected when an undesired fluid is flowing through the VFR system 25 of FIG. 6. When the undesired fluid (e.g. water and/or gas in oil production) enters the chamber 50 through the inlet 80, rotational fluid flow 35 can be induced. Because of the physical properties of the undesired fluid, rotational fluid flow 35 is increased in the chamber 50 and travel time of the fluid 30 through the chamber 50 is increased, thereby decreasing a flow rate of the undesired fluid through the VFR system 25.

FIG. 7B illustrates how the rotational fluid flow 35 can be affected when a desired fluid is flowing through the VFR system 25 of FIG. 6. When the desired fluid (e.g. oil in oil production) enters the chamber 50 through the inlet 80, the rotational flow 35 can be minimized and travel time of the fluid 30 through the chamber 50 is decreased, thereby increasing a flow rate of the desired fluid through the VFR system 25.

FIG. 8 illustrates an embodiment of the VFR system 25 that has two inlets 80 to the chamber 50. The two inlets 80 are shown opposite each other relative to the chamber 50, but they can be otherwise oriented, if desired. For example, the two inlets 80 can be positioned at spaced apart locations other than the 180 degree position shown in FIG. 8. Also, more than two inlets 80 can be used in keeping with the principles of this disclosure.

For purposes of discussion, please refer to FIGS. 14A and 14B which show a partial cross-sectional top view of the VFR system 25 in FIG. 8. FIG. 14A illustrates how the rotational fluid flow 35 can be affected when a desired fluid is flowing through the VFR system 25 of FIG. 8. Very similar to the discussion regarding fluid flow through the VFR system 25 of FIG. 5A, when a desired fluid (e.g. oil in oil production) enters the chamber 50 through the inlets 80, the inlets 80 can direct the fluid flow 33 away from the axis 60 and toward the surfaces 76, 77. The inlets 80 can be angled as shown in the FIGS. 14A and 14B, which can be somewhere between and including tangential to the interior surfaces 76, 77 and slightly directed away from the axis 60 when the fluid 30 enters the chamber 50 via fluid flow 33, thereby directing the fluid flow 33 into rotational fluid flow 35. With desired fluid, the rotational flow 35 can be minimized. Additionally, counter-rotational flow 35 (called “eddy currents”) can be induced in the desired fluid flow through the chamber 50, which tends to further reduce the rotational flow 35, thereby reducing travel time of the desirable fluid in the chamber 50 and increasing a flow rate through the VFR system 25 of the desired fluid.

FIG. 14B illustrates how the rotational fluid flow 35 can be affected when an undesired fluid is flowing through the VFR system 25 in FIG. 8. When the undesired fluid (e.g. water and/or gas in oil production) enters the chamber 50 through the inlet 80, the inlet 80 directs the fluid flow 33 away from the axis 60 and toward the surfaces 76, 77. Because of the physical properties of the undesired fluid, rotational fluid flow 35 is increased in the chamber 50 and travel time of the fluid through the chamber 50 is increased, thereby decreasing a flow rate of the undesired fluid through the VFR system 25.

The VFR system 25 in FIG. 9 is very similar to the previous embodiments of the VFR system 25, except that the chamber 50 is tilted in reference to the central axis 60 of the VFR system 25. The inlet 80 can be perpendicular to either the axis 60 or axis 62, as well as any angle other than these, as long as the angle tends to induce rotational flow of the fluid.

The VFR system 25 in FIG. 10 is very similar in operation to the previous embodiments of the VFR system 25, except that the chamber 50 has an irregular shape, where the irregular shape is not necessarily conically or cylindrically shaped, but rather otherwise curved as indicated by the profile in FIG. 10, as well as possibly having in interior surface 76, 77 that can undulate circumferentially around the chamber 50. The outlet 82 can also be non-circular in shape, such as an oval or polygon shape (including a triangle, rectangle, etc.). The outlet 82 may also be angled relative to the axis 60 as illustrated in FIG. 10. An additional feature shown in FIG. 10 is the protrusion 90 which can extend from the top interior surface 78 into the chamber 50 to further induce or otherwise urge the fluid flow 33, which can be received through the inlet 80, into rotational flow 35 in the chamber 50 The inlet 80 can be perpendicular to the axis 60, as well as any other angle. It should be understood that the protrusion 90 can be used in any of the embodiments of the VFR system 25.

The VFR system 25 in FIG. 11A is very similar to the VFR system 25 in FIG. 6, except that the internal surfaces 76, 77 can be made with a finish that is not smooth. For example, these surfaces can be channeled, splined, recessed, a wavy non-uniform finish and/or otherwise configured to create more turbulent flow in the chamber 50 when rotational fluid flow 35 is experienced by the fluid 30 in the chamber 50. Additionally, various protrusions 90 can be formed that extend from the top interior surface 78 of the chamber 50. FIG. 11A shows only one protrusion 90 extending from the surface 78, however, multiple protrusions 90 can be formed on the surface. The protrusion 90 can also be positioned other than in the center of the VFR system 25, such as in FIG. 11B which has a protrusion with an axis 66 that is spaced away from the axis 60 of the VFR system 25 by a distance C. The protrusion 90 can also form a circumferentially extending protrusion that can at least partially encircle the axis 60. The protrusion 90 can have several other shapes, such as a frusto-conical shape as seen in FIG. 11C, as well as protrusions 90 with cross-sections that are rectangular, triangular, and/or other polygonal shapes.

Other surfaces, such as surfaces 76, 77, 79 can also include these protrusions 90 extending into the fluid flow of the chamber 50 and/or outlet 82. Furthermore, the VFR system 25 can also include recessed features 92, shown in FIG. 11A as recesses with rectangular or triangular cross-sections. These recesses can extend circumferentially around the axis 60 for at least a partial distance and multiple such recesses can be used.

FIG. 12 shows yet another possible embodiment of the VFR system 25. This configuration includes an inlet 80, an outlet 82, and a chamber 50 that can resemble two cone shaped regions joined together at the narrow portion of the cone shapes. This provides a longer flow path for undesired fluids, since the rotation induced by the upper region of the chamber 50 can be supported and maintained in the lower region of the chamber 50. The cross-section of any of the embodiments of the VFR system 25 can be circular, as in the case of a cone-shaped chamber, or rectangular, such as is the case of pyramid-shaped chamber (a square is a rectangle with equal length sides). The chamber cross-section can also be any other polygon shape as desired for controlling fluid flow, which can include a triangular cross-section. The cross-section can also be irregularly shaped, as described above regarding FIG. 10.

FIGS. 15A and 15B each show a partial cross-sectional top view of a VFR system 25 that has a rectangular cross-section (e.g. pyramid shaped). FIG. 15A illustrates how the rotational fluid flow 35 can be affected when a desired fluid is flowing through the VFR system 25. When a desired fluid (e.g. oil in oil production) enters the chamber 50 through the inlet 80, the inlet 80 can direct the fluid flow 33 away from the axis 60 and toward the surfaces 76, 77. The inlet 80 can be angled as shown in the FIGS. 15A and 15B, which can be somewhere between and including tangential to the interior surfaces 76, 77 and slightly directed away from the axis 60 when the fluid 30 enters the chamber 50 via fluid flow 33, thereby directing the fluid flow 33 into rotational fluid flow 35. With desired fluid, the rotational flow 35 can be minimized. Additionally, counter-rotational flow 35 (called “eddy currents”) can be induced in the desired fluid flow through the chamber 50, which tends to further reduce the rotational flow 35, thereby reducing travel time of the desirable fluid in the chamber 50 and increasing a flow rate through the VFR system 25 of the desired fluid.

FIG. 15B illustrates how the rotational fluid flow 35 can be affected when an undesired fluid is flowing through the VFR system 25. When the undesired fluid (e.g. water and/or gas in oil production) enters the chamber 50 through the inlet 80, the inlet 80 directs the fluid flow 33 away from the axis 60 and toward the surfaces 76, 77. Because of the physical properties of the undesired fluid, rotational fluid flow 35 is increased in the chamber 50 and travel time of the fluid through the chamber 50 is increased, thereby decreasing a flow rate of the undesired fluid through the VFR system 25.

Therefore, a system is provided for autonomous flow control of a fluid 30 using one or more variable flow resistance systems 25, where the VFR system 25 can include a body 68 with a chamber 50 configured to induce rotational flow in a fluid 30 that flows through the chamber 50. The chamber 50 can include an inlet 80 through which the fluid 30 enters the chamber 50 and an outlet 82 from which the fluid 30 exits the chamber 50. The chamber 50 can have a cross-sectional area that decreases along a central axis 62 of the chamber 50 toward the outlet 82, where the cross-sectional area is perpendicular to a central axis 62. A resistance to fluid flow through the chamber 50 can vary based on a physical property of the fluid 30.

Other embodiments of the system may also include a well screen assembly 24 with a base pipe 40, a filter layer 53, a drainage layer 52, first and second ends 44, 46 of the assembly 24 secured to the base pipe 40 at opposite ends of the filter layer 53, an annular space 43 within the first end 44, and multiple openings 56 formed in a region 59 on the base pipe 40 defined by the annular space 43. One or more VFR systems 25 can be installed in the multiple openings 56 to tailor the fluid flow resistance and/or flow rate through the well screen assembly 24.

For any of the foregoing embodiments, the claimed system may include any one of the following elements, alone or in combination with each other:

The inlet 80 can be angled away from the central axis 62 of the chamber 50, where the angle of the inlet 80 can induce the rotational flow 35 in the fluid 30. The angle of the inlet 80 can range from being slightly off-center from the central axis 62 of the chamber 50 up to being tangential to an inner surface 77, 76 of the chamber 50.

The physical property of the fluid 30 that can vary the flow resistance can be viscosity, velocity, and/or density. The resistance to the fluid flow through the chamber 50 can be increased when an undesired fluid 30 flows through the chamber 50 and decreased when a desired fluid 30 flows through the chamber 50. The desired fluid 30 can be a hydrocarbon liquid with the undesired fluid 30 being a gas and/or water. Alternatively, the desired fluid 30 can be a gas and the undesired fluid 30 can be a hydrocarbon liquid and/or water.

A cross-sectional area of the chamber 50 can be an oval, a circle, a square, a rectangle, a polygon, or an irregular shape. As used herein, an “irregular shape” refers to a shape that is not an oval, a circle, a square, a rectangle, or a polygon. For example, the irregular shape can be an undulating surface, a wavy surface, a jagged surface, and/or a random surface encircling the central axis 62 of the chamber 50. The chamber 50 can be tapered along the central axis 62 toward the outlet 82. For example, the taper can be due to a chamber 50 with an inverted cone shape, where the inlet 80 is at a base of the cone and the outlet 82 is at a peak of the cone. It should be understood that other shapes (such as pyramid, polygon, etc. as mentioned in this disclosure) can also be tapered from the inlet 80 to the outlet 82. As used herein, “tapered chamber” refers to a chamber 50 with a varied cross-sectional area along the center axis 62 of the chamber 50 with the largest cross-sectional area being proximate the inlet 80 of the chamber 50 and the smallest cross-sectional area being proximate the outlet 82 of the chamber 50. The slope of the chamber surface 76 with the taper does not have to be a linear surface, just that on average, the cross-sectional area of the chamber 50 decreases along the central axis 62 toward the outlet 82.

An inner surface 76, 77, 79 of the chamber 50 can be smooth, grooved, splined, channeled, circumferentially spaced apart recesses, circumferentially spaced apart irregular protrusions, and/or coated with an abrasive material.

A top surface 78 (i.e. top inner surface 78) of the chamber 50 can include a protrusion 90 positioned at the central axis 62, one or more channels positioned circumferentially about the central axis 62, and/or one or more recesses positioned circumferentially about the central axis 62. The protrusion 90 can be positioned at the central axis 62 (or offset from the center axis 62 of the chamber 50), and the protrusion 90 can be a hemi-spherical, a pyramid, a conical, a frusto-conical, a cylindrical, a polygonal, or a tapered polygonal shape.

The central axis 62 of the chamber 50 can be angled relative to a central axis 60 of the body 68. Fluid 30 flowing through the outlet 82 can exit the body 68 through a bottom surface 70 of the body 68 or a side surface 74 of the body 68. A central axis 64 of the outlet 82 can be angled relative to the central axis 62 of the chamber 50.

The well screen assembly 24 can also include multiple VFR systems 25 installed in multiple openings 56 in the annular region 59 of the base pipe 40 of the well screen assembly 24. These VFR systems 25 can be configured for parallel and/or series fluid flow through the well screen assembly 24. Series fluid flow occurs when the outlet 82 of one VFR system 25 is coupled to the inlet 80 of another VFR system 25, so fluid flow through a series connection of VFR systems 25 in the well screen assembly 24 would travel through each VFR system 25 coupled in series. Parallel fluid flow occurs when each VFR system 25 connected in parallel receives fluid 30 through its inlet 80 and outputs fluid 30 from its outlet 82 simultaneously, with the fluid 30 flowing through one of the paralleled VFR systems 25 does not flow through the other paralleled VFR systems 25. Therefore, series connections can increase a fluid flow restriction through the well screen assembly 24, while parallel connections can increase fluid flow rate through the well screen assembly 24.

A quantity of the multiple VFR systems 25 installed in the openings 56 of the well screen assembly 24 in the annular region 59 of the end 44 can be determined by calculating the number of VFR systems 25 needed to produce a desired flow restriction and/or flow rate for flowing the fluid 30 through the well screen assembly 24.

Although various embodiments have been shown and described, the disclosure is not limited to such embodiments and will be understood to include all modifications and variations as would be apparent to one skilled in the art. Therefore, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed; rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.

Tapered Fluidic Diode For Use As An Autonomous Inflow Control Device AICD

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