Patent Grant
11536115
The present description relates to flow control devices used for controlling flow of fluids into a tubular member. In a particular example, the described flow control devices control, or choke, the flow of steam from subterranean formations into production tubing.
Subterranean hydrocarbon reservoirs are generally accessed by one or more wells that are drilled into the reservoir to access the hydrocarbon materials. Such materials are then brought to the surface through production tubing.
The wellbores drilled into the reservoirs may be vertical or horizontal or at any angle there-between. In some cases, the desired hydrocarbons comprise a highly viscous material, such as heavy oil, bitumen and the like. In such cases, it is known to employ steam, gas or other fluids, typically of a lower density to assist in the production of the desired hydrocarbon materials. These agents are typically injected into one or more sections of the reservoir to stimulate the flow of hydrocarbons into production tubing provided in the wellbore. Steam Assisted Gravity Drainage, “SAGD”, is one example of a process where steam is used to stimulate the flow of highly viscous hydrocarbon materials (such as heavy oil, bitumen etc. contained in oil sands). In a SAGD operation, one or more well pairs, where each pair typically comprises two vertically separated horizontal wells, are drilled into a reservoir. Each of the well pairs typically comprises a steam injection well and a production well, with the steam injection well being positioned generally vertically above the production well. In operation, steam is injected into the injection well to heat and reduce the viscosity of the hydrocarbon materials in its vicinity, in particular viscous, heavy oil material. After steam treatment, the hydrocarbon material, now mobilized, drains into the lower production well owing to the effect of gravity, and is subsequently brought to the surface through the production tubing.
Cyclic Steam Stimulation, “CSS”, is another hydrocarbon production method where steam is used to enhance the mobility of viscous hydrocarbon materials. The first stage of a CSS process involves the injection of steam into a hydrocarbon-containing formation through one or more wells for a period of time. The steam is injected through tubing that is provided in the wells. In a second stage, steam injection is ceased, and the well is left in such a state for another period of time that is sufficient to allow the heat from the injected steam to be absorbed into the reservoir. This stage is referred to as “shut in” or “soaking”) during which the viscosity of the hydrocarbon material is reduced. Finally, in a third stage, the hydrocarbons, now mobilized, are produced, often through the same wells that were used for steam injection. The CSS process may be repeated as needed.
The tubing referred to above typically comprises a number of coaxial pipe segments, or tubulars, that are connected together. Various tools are often provided along the length of the tubing and coaxially connected to adjacent tubulars. The tubing, for either steam injection or hydrocarbon production, generally includes a number of apertures, or ports, along its length, particularly in the regions where the tubing is provided in hydrocarbon-bearing regions of the formation. The ports provide a means for injection of steam, and/or other viscosity reducing agents from the surface into the reservoir, and/or for the inflow of hydrocarbon materials from the reservoir into the tubing and ultimately to the surface. The segments of tubing having ports are also often provided with one or more filtering devices, such as sand screens and the like, which serve to prevent or mitigate against sand and other solid debris in the well from entering the tubing.
As known in the art, particularly when steam is used to stimulate production of heavy hydrocarbon materials, the steam preferential enters the production tubing over the desired hydrocarbon materials. This generally occurs in view of the fact that steam has a lower density than the hydrocarbon material and is therefore more mobile or flowable. This problem is faced, for example, in SAGD operations where the steam from the injection well travels or permeates through the hydrocarbon formation and is preferentially produced in the production well.
To address the above-noted problem, steps are often taken to limit, or “throttle” or “choke”, the flow of steam into production tubing, and thereby increase the production rate of hydrocarbon materials. To this end, various nozzles and other devices have been proposed that are designed to limit the flow of steam into production tubing. In some cases, a device such as a flow restrictor or similar nozzle is provided on a “base pipe” of the tubing to impede the inflow of steam. Examples of such flow control devices are described in: U.S. Pat. Nos. 9,638,000; 7,419,002; 8,496,059; and US 2017/0058655. Another apparatus for steam choking is described in the present applicant's co-pending PCT application, WO 2019/090425, the entire contents of which are incorporated herein by reference.
There exists a need for an improved flow control means to control or limit the introduction of steam into production tubing.
In one aspect, there is provided a nozzle for controlling flow into a pipe, the pipe having at least one port along its length, the nozzle being adapted to be located on the exterior of the pipe, adjacent one of the at least one port, and wherein the nozzle chokes the flow of steam while preferentially allowing the flow of hydrocarbons and hydrocarbon-containing liquids.
In one aspect, there is provided a system for controlling flow of fluids from a hydrocarbon-containing subterranean reservoir into production tubing, the system comprising:
In another aspect, there is provided a nozzle for controlling flow of fluids from a subterranean reservoir into a port provided on a pipe, the nozzle being adapted to be located on the exterior of the pipe adjacent the port, the nozzle having an inlet for receiving reservoir fluids, an outlet arranged in fluid communication with the port, and a fluid conveying passage, extending between the inlet and the outlet, for channeling reservoir fluids in a first direction from the inlet to the outlet;
The features of certain embodiments will become more apparent in the following detailed description in which reference is made to the appended figures wherein:
As used herein, the terms “nozzle” or “flow control device”, as used herein, will be understood to mean a device that controls the flow of a fluid flowing there-through. In one example, the nozzle described herein is an “inflow control device” or “inflow control nozzle” that serves to control the flow of fluids through a port from a subterranean formation into a pipe for production operations. It will be understood, that such nozzles may also allow for flow of fluids in an opposite direction, such as for injection operations.
The terms “regulate”, “limit”, “throttle”, and “choke” may be used herein. It will be understood that these terms are intended to describe an adjustment of the flow rate of a fluid passing through the nozzles described herein. As discussed herein, the present nozzles are specifically designed to choke the flow of a low viscosity fluid, in particular steam. For the purposes of the present description, the flow of a fluid is considered to be “choked” if a further decrease in downstream pressure does not result in an increase in the velocity of the fluid flowing through the restriction. That is, the fluid velocity is limited and as a result, and assuming that all other variables remain unchanged, the mass flow rate of the fluid is also limited.
The term “hydrocarbons” refers to hydrocarbon compounds that are found in subterranean reservoirs. Examples of hydrocarbons include oil and gas. As will be apparent from the present description, the nozzles described herein are particularly suited for reservoirs containing heavy oils or similar high viscosity hydrocarbon materials.
The term “wellbore” refers to a well or bore drilled into a subterranean formation, in particular a formation containing hydrocarbons.
The term “wellbore fluids” refers to hydrocarbons and other materials contained in a reservoir that enter a wellbore. The present description is not limited to any particular wellbore fluid(s).
The terms “pipe” or “base pipe” refer to a section of pipe, or other such tubular member. The base pipe may be provided with one or more openings or slots, collectively referred to herein as ports, at various positions along its length to allow flow of fluids there-through.
The terms “production” or “producing” refers to the process of bringing wellbore fluids, in particular the desired hydrocarbon materials, from a reservoir to the surface.
The term “production tubing” refers to a series of pipes, or tubulars, connected together and extending through a wellbore from the surface into the reservoir. Production tubing may be used for producing wellbore fluids.
The terms “screen”, “sand screen”, “wire screen”, or “wire-wrap screen”, as used herein, refer to known filtering or screening devices that are used to inhibit or prevent sand or other solid material from the reservoir from flowing into production tubing. Such screens may include wire wrap screens, precision punched screens, premium screens or any other screen that is provided on a base pipe to filter fluids and create an annular flow channel. The present description is not limited to any particular screen or screen device.
The terms “comprise”, “comprises”, “comprised” or “comprising” may be used in the present description. As used herein (including the specification and/or the claims), these terms are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not as precluding the presence of one or more other feature, integer, step, component or a group thereof as would be apparent to persons having ordinary skill in the relevant art.
In the present description, the terms “top”, “bottom”, “front” and “rear” may be used. It will be understood that the use of such terms is purely for the purpose of facilitating the present description and are not intended to be limiting in any way unless indicated otherwise. For example, unless indicated otherwise, these terms are not intended to limit the orientation or placement of the described elements or structures.
The present description relates to a flow control device or nozzle, in particular an inflow control device, for controlling or regulating the flow of fluids from a reservoir into production tubing. As discussed above, such regulation is often required in order to preferentially produce desired hydrocarbon materials instead of undesired fluids, such as steam. As also discussed above, the production of steam, such as in a SAGD operation, commonly occurs as steam has a much lower density than many hydrocarbon materials, such as heavy oil and the like. The steam, being much more mobile than the heavy oil, also preferentially travels towards and into the production tubing. The nozzles described herein serve, in one aspect, to throttle or regulate the inflow of steam into production tubing.
As would be understood by persons skilled in the art, the nozzles described herein are preferably designed to be included as part of an apparatus associated with tubing, an example of which is illustrated in
a illustrate one aspect of a nozzle according to the present description. As shown, the nozzle 10 comprises a generally cylindrical body (as shown by way of example in
The inlet 12 is formed with a gradually narrowing opening 13, that forms a region of reducing cross-sectional area. The opening 13 preferably has a smooth wall according to one aspect. Thus, the opening 13 has a generally funnel-like shape.
The inlet 12 extends to the throat 16, where the diameter of the opening is reduced to d2. The throat 16 may be of any length having a constant diameter, or cross-sectional area.
As would be understood from the present description, the length of the opening 13, extending from the inlet 12 to the throat 16, and the length of the throat 16 may be of any size and may vary depending on the characteristics of the fluids being produced. In particular, as discussed below, the purpose of the narrowing opening 13 and throat 16 is to increase the velocity and reduce the pressure of the fluid flowing there-through. Persons skilled in the art would therefore appreciate the length of the opening required to achieve this result based upon the nature of the fluids in the reservoir in question. An example of a nozzle according to the present description and having an elongated throat section is shown in
The portion of the passage extending from the throat 16 and in the direction 11 is provided with an increasing diameter, up to at least the diameter d3 of the outlet 14. In this way, the portion of the nozzle passage extending from the inlet 12 to the throat 16 comprises a converging section 18 and the portion of the passage downstream from the throat 16 and towards the outlet 14 (that is, in the direction 11) comprises a diverging section 20, which opens into an expansion, or pressure recovery region 24. As will be understood, in region 20, the velocity of the flowing fluids is decreased resulting in an increase in pressure. In
As shown in
In contrast to a Venturi nozzle, the nozzle 10 of
Thus, with the structure of the subject nozzle 10, in particular with the presence of the corner 22, a hot fluid (such as steam or a hot gas) flowing through the passage of the nozzle 10 is subjected to a pressure drop in the throat 16 and is flashed (i.e. the pressure within the throat is reduced below the vapour pressure of the fluid). The flowing fluid is then subjected to mixing at the corner 22. In the absence of steam or where the concentration of steam is below a certain value, the vapour pressure of the fluid is below the pressure in the throat 16 and, therefore, the flow rate of the fluid is maintained. Therefore, the present nozzle 10 provides an improvement in steam choking as compared to known Venturi nozzles.
More specifically, and without being bound to any particular theory, fluid flowing from a reservoir into production tubing may comprise one or more of: a “cold fluid”, comprising a single phase of steam/water and hydrocarbons; a “hot fluid”, comprising more than one phase, in particular a steam phase and a liquid hydrocarbon phase; and, steam, in particular wet steam, which may also contain a hydrocarbon component but would still constitute a single phase. The nozzle described herein is primarily designed to convert a “hot fluid”, or multiple phase fluid, into a single phase.
When wet steam or a hot fluid and steam mixture is flowed through the presently described nozzle, the converging section will cause acceleration of the fluid flow, that is, an increase in the fluid velocity. This increase in velocity is associated with a corresponding decrease in the pressure of the fluid. The generated pressure drop will generally result in the separation of steam from the fluid mixture, thereby resulting in a more discrete steam phase. Ideally, before the fluid reaches the corner 22, the steam will be completely separated and will reach a state of equilibrium with the water content of the flowing fluid. Once removed from the rest of the fluid, and into a separate phase, it will be understood that the steam would have an increased velocity as it travels through the nozzle. This increased velocity is believed to serve as a carrier for the liquid phase of the fluid. As will be understood, the increase in velocity that is achieved by the nozzle described herein serves to further increase the pressure drop of the fluid, wherein, according to Bernoulli's principle, such pressure drop is proportional to the square of the flow velocity. In other words, an increase in the fluid velocity results in an exponential increase in the pressure drop. Thus, in one aspect, the nozzle described herein achieves a greater pressure drop by increasing the fluid velocity in a unique manner.
The expansion region 24 of the nozzle, following after corner 22, functions as a pressure recovery chamber, where the total pressure of the flowing fluid is increased, or “recovered”. In the expansion region 24, the steam/water (in equilibrium) and hydrocarbon phases of the fluid are combined into a single phase. Preferably, in the expansion region 24, the fluid pressure is increased to the prescribed outlet pressure so as to avoid the formation of shockwaves within the nozzle. Compared to the long gradual expansion section in a known Venturi nozzle, the sharp corner 22 of the presently described nozzle provides the immediate and initial expansion for the pressure recovery. Thus, by using a nozzle as described herein with the corner 22, a high-quality (i.e. hydrocarbon rich) flow can be maintained with a relatively shorter nozzle.
As illustrated, the nozzle 110 of
It will be understood that the system of the present description does not necessarily require the presence of a screen, although such screens are commonly used. The present description is also not limited to any type of screen 304 or screen retaining device or mechanism 306.
The present description is also not limited to any number of ports 302. Furthermore, it will be appreciated that while the presence of a screen 304 is shown, the use of the presently described nozzle is not predicated upon the presence of such screen. Thus, the presently described nozzle may be used on a pipe 300 even in the absence of any screen 304. As would be understood, in cases where no screen is used, a retaining device, such as a clamp 306 or the like, may still be utilized to secure nozzle 210 to the pipe 300. Alternatively, the nozzle 210 may be secured to the pipe in any other manner as would be known to persons skilled in the art.
As shown in
As shown in
In use, the pipe 300 is provided with the nozzle 210 and, where needed, the screen 304. The pipe 300 is then inserted into a wellbore to begin the production procedure. During production, wellbore fluids, as shown at 308, pass through the screen 304 (if present) and are diverted to the nozzle 210. As discussed above, the nozzle 210 has a passageway with converging and diverging sections. Where the wellbore fluids primarily comprise desired hydrocarbons, such as oil and heavy oil etc., flow through the nozzle 210 is uninterrupted and such fluids enter into the port 302 and into the pipe, or production tubing 300. However, where the fluids 308 comprise steam (as would occur in steam breakthrough in a SAGD operation), the nozzle functions as described above and effectively chokes the flow of such low-density fluid. Other ports along the length of the pipe would continue to produce the desired hydrocarbons. In the result, over its length, the pipe, or production tubing, would preferentially produce hydrocarbons while choking the flow of steam at those regions where steam breakthrough has occurred.
As will be understood, although the present description is mainly directed to the choking of steam inflow, the presently described nozzles may also be used to choke the flow of other “undesired” fluids such as water and gas that are found in combination with desired hydrocarbons, or other low density fluids that are injected into the formation such as viscosity modifiers, solvents etc.
A further aspect of the present description is shown in
In one example, the nozzle 410 illustrated in
It will be understood that the dimensions of the nozzle described herein will vary based on the intended use. For example, the diameter of the throat d2 would generally be determined by the pressure of the reservoir and the desired production rate. Generally, the length of the nozzle would be fixed as it would be limited by the equipment being used for the production phase.
A further aspect of the present description is shown in
In one example, the nozzle 510 illustrated in
The throat 716 also includes a duct region shown at 726 that is similar to the duct region 26 shown in
In one example, the nozzle of
The above example of the nozzle of
As shown in
The throat 816 forms the second converging region 817 and comprises a narrowed region, or constriction in the passage of the nozzle 810. More particularly, as shown in
The outlet 814 is provided with an outlet diameter d3 that is larger than d2 or d4 and, in one aspect, larger than d1.
The portion of the passage extending from the end of the second converging region 817, that is the corner 822, to the outlet 814 (i.e. in the direction 11) forms the diverging region 824 of the nozzle 810 passage and is provided with an increasing diameter ranging from d2 up to at least the diameter d3 of the outlet 814. In one aspect, as illustrated in
In
As shown in
More specifically, and without being bound to any particular theory, fluid flowing from a reservoir into production tubing may comprise one or more of: a “cold fluid”, comprising a single phase of steam/water and hydrocarbons; a “hot fluid”, comprising more than one phase, in particular a steam phase and a liquid hydrocarbon phase; and, steam, or, more particularly wet steam, which may also contain a hydrocarbon component but would still constitute a single phase. The nozzle described herein is primarily designed to convert a hot fluid into a single phase.
When wet steam or a hot fluid and steam mixture is flowed through the presently described nozzle, the converging regions 815 and 817 will cause acceleration of the fluid flow, and thus an increase in the fluid velocity. This increase in velocity is associated with a corresponding decrease in the pressure of the fluid. The generated pressure drop will generally result in steam to separate from the fluid mixture, thereby resulting in a more discrete steam phase. Ideally, before the fluid reaches the expansion region 824, the steam will be completely separated and will reach a state of equilibrium with the water content. Once removed from the rest of the fluid, and into a separate phase, it will be understood that the steam would have an increased velocity as it travels through the nozzle. This increased velocity is believed to serve as a carrier for the liquid phase of the fluid. As will be understood, the increase in velocity that is achieved by the nozzle described herein serves to further increase the pressure drop of the fluid, wherein, according to Bernoulli's principle, such pressure drop is proportional to the square of the flow velocity. In other words, an increase in the fluid velocity results in an exponential increase in the pressure drop. Thus, in one aspect, the nozzle described herein achieves a greater pressure drop by increasing the fluid velocity in a unique manner.
The expansion region 824 of the nozzle, following the throat 816, functions as a pressure recovery chamber, where the total pressure of the flowing fluid is increased, or “recovered”. In the expansion region 824, the steam/water (in equilibrium) and hydrocarbon phases of the fluid are combined into a single phase. Preferably, in the expansion region 824, the fluid pressure is increased to the prescribed outlet pressure so as to avoid the formation of shockwaves within the nozzle.
With the nozzle described herein, the converging regions 815 and 817 have smooth, curved shapes, which helps the inflow of both single-phase liquid and the unwanted wet steam. The first converging region 815 of the nozzle 810, preferably having a smooth wall, promotes the flow of the single-phase liquid there-through due to the higher viscosity of such fluid. The throat 816, downstream of the first converging section 815 functions to further encourage the steam component to separate from the fluid and reach an equilibrium state. As mentioned above, the throat 816 may also comprise a smooth walled surface. Thus, the throat 816 serves to further accelerate the fluid passing there-through and further augment the pressure drop mentioned above. Downstream of the throat 816, flow velocity is proportional to the volumetric flow rate. Therefore, when steam is completely separated from the fluid, the volumetric flow rate will be increased, and the pressure drop (i.e. the pressure difference) will be increased accordingly.
The nozzle 810 may be utilized in the same manner as discussed above, such as in reference to
As will be understood, although the present description is mainly directed to the choking of steam inflow, the presently described nozzles may also be used to choke the flow of other “undesired” fluids such as water and gas or other fluids that injected into the formation such as viscosity modifiers, solvents etc.
In the present description, the fluid passage of the nozzles has been described as having a smooth wall. However, in certain cases, the wall may be provided with a rough or stepped finish.
Although the above description includes reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art. Any examples provided herein are included solely for the purpose of illustration and are not intended to be limiting in any way. In particular, any specific dimensions or quantities referred to in the present description is intended only to illustrate one or more specific aspects are not intended to limit the description in any way. Any drawings provided herein are solely for the purpose of illustrating various aspects of the description and are not intended to be drawn to scale or to be limiting in any way. The scope of the claims appended hereto should not be limited by the preferred embodiments set forth in the above description but should be given the broadest interpretation consistent with the present specification as a whole. The disclosures of all prior art recited herein are incorporated herein by reference in their entirety.
This application claims priority to PCT Application No. PCT/CA2019/050942, filed Jul. 8, 2019; U.S. Application No. 62/694,977, filed Jul. 7, 2018; and U.S. Application No. 62/695,625, filed Jul. 9, 2018. The contents of these prior applications are incorporated herein by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CA2019/050942 | 7/8/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/010449 | 1/16/2020 | WO | A |
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| Number | Date | Country | |
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| 20210254435 A1 | Aug 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62695625 | Jul 2018 | US | |
| 62694977 | Jul 2018 | US |
