Patent Publication Number: US-2021172299-A1

Title: Flow control device for production tubing

Description:
FIELD OF THE DESCRIPTION 
     The present description relates to flow control devices used for controlling flow into or out of pipes, in particular pipes used in oil and gas wells. 
     BACKGROUND 
     Hydrocarbon reservoirs, such as oil and/or gas reservoirs, are generally accessed by wells that are drilled into the subterranean reservoir and the hydrocarbon materials are then brought to the surface through production tubing. Production tubing consists of a plurality of pope section that connected together and inserted into the well. The well may be cased or uncased. The production tubing may also include various other tools that connected between the pipe sections, such as packers etc. 
     The wellbore may be vertical or horizontal or at any angle there-between. In some cases, where the hydrocarbons comprises a highly viscous material, such as heavy oil and the like, steam, gas or other fluids may be injected into one or more sections of the reservoir to stimulate the flow of hydrocarbons into the wellbore. 
     Steam Assisted Gravity Drainage, “SAGD”, is one example of a process that is used to stimulate the flow of highly viscous oil. In a SAGD operation, two wells, typically horizontal wells, are drilled within a reservoir. The wells comprise an upper, steam injection well, and a lower production well. In operation, steam is injected into the injection well to heat and reduce the viscosity of the hydrocarbon material. After steam treatment, the hydrocarbon material, now mobilized, drains into the production well and subsequently brought to the surface by production tubing. Cyclic Steam Stimulation, “CSS”, is another example where steam is used to enhance the mobility of viscous hydrocarbon materials. In a CSS process, a single well is used to first inject steam into the reservoir through tubing, generally production tubing. Thereafter, the heat from the steam is allowed to be absorbed into the reservoir (a stage referred to as “shut in” or “soaking”), during which the viscosity of the hydrocarbon material is reduced. Following such stage, the hydrocarbons are produced in a production stage. 
     Production tubing used in wellbores typically includes a number of coaxial segments, or tubulars, that are connected together. Various tools may also be provided along the length of the tubing, wherein such tools comprise a base pipe with one or more apertures, or ports, provided along its length. The ports provide a means for the inflow of hydrocarbon materials from the reservoir into the pipe and thus into the production tubing. The ports may also provide a means for the outflow, or injection of steam and/or other viscosity reducing agents from the production tubing into the reservoir. The segments having ports are also often provided with one or more filtering devices, such as wire screens, or wire-wrap screens, which serve to filter the hydrocarbon materials being produced and thereby prevent or mitigate against sand and other solid debris in the well from entering the base pipe and therefore the production tubing. 
     In view of the length of production tubing (which may be in the range of several thousand meters), steps must often be taken to ensure that the production rates along its length are near constant. This is to avoid preferential production from one region of a reservoir, which may result in another region not be being produced. In addition, in cases where regions of the reservoir are under high pressure, the pressure of the produced fluids may result in damage to the tubing material. Similarly, in situations where steam or another fluid is being injected, it is important to ensure that the injection is accomplished evenly so as to avoid preferential stimulation of only certain regions of the reservoir. 
     Various devices have been proposed for controlling the rates of production and/or injection between tubing and a reservoir. In some cases, a device such as a flow restrictor or similar nozzle is associated with the base pipe to impede the flow of fluids flowing into or from the pipe. Examples of such flow control device are described in the following references: U.S. Pat. Nos. 9,518,455; 9,638,000; 9,027,642; 7,419,002; 8,689,883; 9,249,649, US 2017/0058655 and US 2009/0078428. 
     There exists a need for an improved flow control means to control the flow of reservoir fluids entering into production tubing. 
     SUMMARY OF THE DESCRIPTION 
     In one aspect, there is provided an apparatus for regulating the flow of reservoir fluid entering into production tubing provided in a wellbore. In particular, the apparatus reduces or attenuates the pressure of the fluid entering into the production tubing. 
     In one aspect, there is provided an apparatus for controlling flow of fluids from a subterranean reservoir into production tubing provided in a well in the reservoir, the apparatus comprising:
         a base pipe, adapted to be connected to the production tubing, the base pipe having a first end and a second end and at least one port extending through the wall thereof for conducting reservoir fluids into the base pipe;   a screen for filtering reservoir fluids entering the port, the screen being provided on the outer surface of the base pipe;   a nozzle provided between the screen and the port, the nozzle having a nozzle channel for receiving fluids filtered by the screen, the nozzle channel extending between an inlet and an outlet of the nozzle;   the nozzle channel having a throat provided downstream of the nozzle inlet and a diverging section downstream of the throat, whereby the nozzle channel is provided with a converging-diverging profile; and,   a diverter provided adjacent the nozzle outlet for diverting fluid exiting the nozzle into the port, the diverter having a diverter channel extending between an inlet, adapted to receive fluids exiting the nozzle outlet, and an outlet fluidly connected to the port on the base pipe, whereby fluids exiting the diverter enter the port.       

     In another aspect, there is provided an apparatus for controlling flow of fluids from a subterranean reservoir into production tubing provided in a well in the reservoir, the apparatus comprising:
         a base pipe, adapted to be connected to the production tubing, the base pipe having a first end and a second end and at least one port extending through the wall thereof for conducting reservoir fluids into the base pipe;   a screen for filtering reservoir fluids entering the port, the screen being provided on the outer surface of the base pipe; and,   a nozzle provided between the screen and the port, the nozzle having a nozzle channel for receiving fluids filtered by the screen, the nozzle channel extending between an inlet and an outlet of the nozzle;   the nozzle channel having: a throat provided downstream of the nozzle inlet; a diverging section downstream of the throat; and, an outlet section downstream of the diverging section; the outlet section extending to the nozzle outlet and having a constant cross-sectional area.       

    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The features of certain embodiments will become more apparent in the following detailed description in which reference is made to the appended figures wherein: 
         FIG. 1  is a partial cross-sectional view of a flow control apparatus according to an aspect of the description. 
         FIG. 2  is an enlarged section of the apparatus of  FIG. 1 . 
         FIG. 3  is an end view of a nozzle according to an aspect of the description. 
         FIG. 4  is a side cross-sectional view of the nozzle of  FIG. 3  taken along line A-A. 
         FIG. 5  is a side perspective view of the nozzle of  FIGS. 3 and 4 . 
         FIG. 6  is another cross-sectional view of the nozzle shown in  FIGS. 3 and 4 . 
         FIG. 7  is a top front perspective view of a diverter according to an aspect of the description. 
         FIG. 8  is a top view of the diverter of  FIG. 7 . 
         FIG. 9  is a rear view of the diverter of  FIG. 7 . 
         FIG. 10  is a side view of the diverter of  FIG. 7 . 
         FIG. 11  is a side cross-sectional view of a diverter according to another aspect of the description. 
     
    
    
     DETAILED DESCRIPTION 
     As used herein, the terms “nozzle” or “nozzle insert” will be understood to mean a device that controls the flow of a fluid flowing there-through. In one example, the nozzle described herein serves to control the flow of a fluid through a port in a pipe in at least one direction. 
     The term “hydrocarbons” refers to hydrocarbon compounds that are found in subterranean reservoirs. Examples of hydrocarbons include oil and gas. 
     The term “wellbore” refers to a bore drilled into a subterranean formation, such as a formation containing hydrocarbons. 
     The term “wellbore fluids” refers to hydrocarbons and other materials contained in a reservoir that are capable of entering into a wellbore. 
     The terms “pipe” or “base pipe” refer to a section of pipe, or other such tubular member. The base pipe is generally provided with one or more ports or slots along its length to allow for flow of fluids there-through. 
     The term “production” refers to the process of producing wellbore fluids. 
     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. 
     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 the pipe. 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 described herein. 
     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 description of the embodiments described herein. These terms are not intended to limit the orientation or placement of the described elements or structures. 
       FIG. 1  illustrates a partial side cross sectional view of an embodiment of an apparatus that may be used for controlling the production rate from a reservoir.  FIG. 2  illustrates an enlarged view of a portion of the apparatus of  FIG. 1 . The apparatus  10  comprises a base pipe  12  that is adapted to be connected to members of a tubing string, or production string. Such members are commonly referred to as tubulars. As with tubulars, the base pipe  12  would be provided with a threaded male portion, or “pin”, at one end a threaded female portion, or “box”, at the opposite end. As known in the art, each of such ends (not shown in  FIG. 1 ) would be adapted to connect to a corresponding end of an adjacent tubular. It will be understood that in some instances other tools or components (such as packers etc.) may be provided on the production string and that such other components may be positioned adjacent to the base pipe  12 . 
     The apparatus  10  also includes a filter or screen as known in the art. In the example illustrated in the accompanying figures, the filter is a wire screen  14 , which, as known in the art, comprises a plurality of circumferentially spaced rib wires  16  that extend longitudinally over a portion of the base pipe  12 . The wire screen  14  also includes a circumferential wire wrap  18  provided over the ribs  16 . As would be known to persons skilled in the art, the wire screen  14  results in a plurality of longitudinally extending channels between adjacent rib wires  16 . In addition, each winding of the wire wrap  18  is spaced by a given distance, thereby allowing fluids to pass there-through but filtering out solid material having a diameter greater than the spacing between the wires. As indicated above, although a wire screen, or wire-wrap screen, is described herein, it will be understood that various other filtering devices may be used with the apparatus described herein. The present description is not intended to be limited to any particular filtering device. For example, the filtering device may comprise a slotted liner or the like, which serves to filter fluids and create an annular flow channel whereby fluids are flowed to one or more ports on a base pipe. Although the present description will refer to a wire screen for convenience, it will be understood that this is not intended to be limiting in any way. 
     As known in the art, the wire screen  14  is secured to the base pipe  12  and this may be accomplished by various means. In one aspect, the wire screen  14  is secured to the base pipe  12  by means of circumferential collars provided on each end of the screen. As shown in  FIG. 1 , a first collar  20  is provided on a first end of the wire screen  14  and a second collar  22  is provided on a second end of the wire screen. The collars  20  and  22  may be secured to the base pipe  12  by any known means. In one aspect, the collars may be welded to the base pipe  12 . 
     The apparatus includes an annular space  24  adjacent the second end of the wire screen  14 , as described further below. 
     The base pipe  12  includes at least one port or aperture  26  providing fluid communication to the lumen of the pipe. The pipe  12  is preferably also provided with a recess  13  on the outer surface of thereof. In a preferred embodiment, the recess  13  is provided around the port  24 . The recess  13  is sized to receive and retain a diverter  28 . As shown in  FIGS. 1 and 2 , the diverter  28  includes an outlet  30  that is fluidly connected to the port  24 , whereby fluids exiting the outlet  30  of the diverter  28  enter into the base pipe  12  through the port  24 . As illustrated in the accompanying figures, the diverter outlet  30  is provided on a surface of the diverter  28  that contacts the outer surface of the base pipe  12 . As shown in  FIGS. 1 and 2 , when the diverter is provided on the base pipe  12 , the diverter outlet  30  is adapted to overlie the port  24  so as to be fluidly connected thereto. Further description of the diverter  28  is provided below. 
     The apparatus further includes a nozzle  32  positioned between the annular space  24  adjacent the wire screen  14  and the diverter  28 . As more clearly shown in  FIG. 2 , the nozzle includes an inlet  34  adjacent the annular space  24 , and an outlet  36  adjacent to, and preferably connected to an inlet  38  of the diverter. As would be understood, when the apparatus is in use, fluids from the reservoir pass through the wire screen and enter into the annular space  24  and then enter into the inlet  34  of the nozzle  32 . The fluids pass through the nozzle  32 , exiting the outlet  36  thereof and enter into the inlet  38  of the diverter  28 . The fluids then pass through the outlet  36  of the diverter  28  entering the port  26  and consequently into the lumen of the base pipe  12 . As noted above, the base pipe  12  is connected to and forms part of the production string and, as such, the fluids entering through the port  26  are produced at the surface. 
     As noted above, the base pipe  12  shown in  FIGS. 1 and 2  includes a recess  13  for receiving and retaining the diverter  28 . It will be understood that in other embodiments a similar recess may be provided on the base pipe  12  for receiving and retaining the nozzle  32 . 
     The nozzle  32  will now be discussed in further detail. As shown more clearly in  FIG. 2 , the nozzle includes a channel  40  extending there-through, from the inlet  34  to the outlet  36 . The channel  40  includes a throat  42  adjacent to and downstream from the inlet  34 . Further downstream of the throat  42 , the channel  40  includes a diverging region  44  having an increasing cross-sectional area in the direction extending between the throat  42  and the outlet  36 . In one aspect, the diverging region  44  extends to the outlet  36 . However, in the embodiment illustrated in  FIGS. 1 and 2 , the diverging region  44  extends only partway along the length of the channel  40 , terminating in a region of constant cross-sectional area  46 . As will be understood, the combination of the throat  42  and the diverging region  44  result in the nozzle having a convergent-divergent channel, such as a Venturi tube. As would be understood by persons skilled in the art, as fluids entering the inlet  34  of the nozzle are passed through the converging throat  42  and the diverging region  44 , the pressure of the fluids is dissipated while its velocity is increased. 
     As illustrated in  FIGS. 1 and 2 , the fluid passing through the channel  40  of the nozzle  32  generally maintain a flow path that extends longitudinally along the base pipe  12 . Once the fluid passes through the nozzle  32 , it enters the diverter  28 , which serves to divert the flow path of the fluid from one extending longitudinally to one extending generally radially with respect to the base pipe  12 . As shown in the figures, the diverter  28  includes a channel  48  extending between the inlet  38  and outlet  30  thereof. The channel  48  includes a bend resulting in the inlet  38  and outlet  30  being generally orthogonal to each other. As will be understood, fluid entering the nozzle  32  (as described above), subsequently enters the diverter  28  and then into the pipe  12  through the port  26 . 
     As illustrated in  FIGS. 1 and 2 , the second collar  22 , is sized so as to overlap the wire screen  14  as well as the nozzle  32  and the diverter  28 . The collar  22  may be adapted to receive and retain the nozzle  32  and/or the diverter  28  in position over the pipe when the collar  22  is secured thereto. As more clearly shown in  FIG. 2 , the collar  22  is provided with a recess  29  for the purpose of receiving and retaining the diverter  28 . It will be understood that in another embodiment the collar  22  may include a further recess for receiving and retaining the nozzle  32 . 
       FIGS. 3 to 6  illustrate the nozzle of the present description in isolation, wherein the same reference numerals are used to identify similar elements. As shown, the nozzle  32  comprises a body having a generally monolithic structure. The inlet  34 , in the same manner as described above, comprises an opening into a channel  40 . The channel  40  includes a throat  42  located downstream from the inlet  34 . As discussed above, the throat  42  serves as a choke point or point of convergence for fluid flowing there-through. In one embodiment, the throat  42  comprises a smooth curved wall, as illustrated, at both the inlet end and the outlet end thereof. However, in other embodiments, the wall of the throat and the surrounding region of the channel  40  may be provided with a stepped cross-sectional appearance. As discussed above, the throat  42  serves to dissipate pressure of the fluid flowing through the channel  40 . As will be understood, by providing the throat with a stepped wall, or other such geometry that is not smooth, the throat will be able to dissipate even further pressure of the flowing fluid. 
     Downstream from the throat  42 , the channel  40  is provided with a region of increasing diameter, or a diverging region  44 , and an outlet  36 . In one embodiment, as illustrated, the channel  40  includes a region of constant cross-sectional area,  46 , between the diverging region  44  and the outlet  36 . In the illustrated embodiment, the diverging region  44  and, where present, the region of constant diameter  46  are provided with smooth walls. However, as with the throat  42 , the walls of these regions may also, together or independently, be provided with a stepped or otherwise non-smooth surface to enhance the dissipation of pressure of the fluid flowing there-through. 
       FIG. 5  illustrates a side view of the nozzle  32  while  FIG. 6  illustrates a perspective cross-sectional view thereof. 
       FIGS. 7 to 10  illustrate an embodiment of the diverter  28 . As shown, the diverter comprises a monolithic element that is positioned within the recess  13  in the base pipe  12  as described above. As also discussed above, the diverter  28  has an opening or inlet  38  that, when in use, receives fluids exiting the nozzle  32 . In one aspect, the inlet  38  of the diverter  28  is provided with a recess  39  for receiving the end of the nozzle  32  having the outlet  36 . As would be understood, the recess  39  facilitates the flow of fluid from the nozzle outlet  36  into the diverter inlet  38 . The diverter  28  also includes an outlet  30  that, when in use, diverts the fluid into a port on the pipe as described above. As mentioned above, the diverter  28  includes an internal channel  48  extending between the inlet  38  and outlet  30  and through which the fluid flows. The channel  48  is shown in phantom in  FIGS. 8 to 10 . In the embodiment shown in  FIGS. 7 to 10 , the diverter channel  48  comprises an arcuate elbow extending between the inlet  38  and outlet  30 . The channel  48  may, in one aspect, comprise a smooth, curved surface shown in phantom at  50  in  FIGS. 8 to 10 . In another embodiment, the surface of the diverter channel  48  may have a stepped or other such non-smooth surface. 
     As also shown, the outlet  30  has a larger cross-sectional area than the inlet  38 . As such, the diverter channel  48  is preferably provided with an increasing cross-sectional area extending in the direction from the inlet  38  to the outlet  30 . In this way, the diverter serves to further reduce the pressure of the fluid flowing there-through while diverting the fluid into the base pipe. 
       FIG. 11  illustrates another embodiment of the diverter wherein like elements are identified with like reference numerals but with the letter “a” added for clarity for elements that are variants. As shown in  FIG. 11 , the diverter  28   a  includes an inlet  38   a  and an outlet  30   a . Although not shown, the diverter inlet  38   a  may include a recess (such as that shown at  39  in  FIG. 7 ) for receiving the outlet end of the nozzle. In this embodiment, the diverter channel  48   a  comprises two sections, namely and inlet section  52  and an outlet section  54 , that are connected at an elbow  56 . As illustrated in  FIG. 11 , the inlet section  52  of the channel  48   a  comprises a generally linear conduit that is aligned with the channel of the nozzle. As described above, the inlet section  52  of the channel  48   a  receives fluid exiting the nozzle  32 . In the embodiment shown in  FIG. 11 , the inlet section  52  of the channel  48   a  is provided with a generally constant cross-sectional area. As such, the inlet section  52  may be cylindrical in shape. The outlet section  54  of the diverter channel  48   a , however, comprises a diverging channel, having an increasing cross-sectional area in the direction towards the outlet  30   a . In the embodiment shown, the outlet section  54  has a generally conical, or frustoconical shape extending from the elbow  56  to the outlet  30 . As also shown, the outlet section  54  is provided at an angle with respect to the inlet section  52 . As will be understood, the diverging nature of the channel  48   a , in particular the outlet section  54  thereof, further serves to reduce the pressure of the fluid passing there-through. 
     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. 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.