Patent Publication Number: US-9428989-B2

Title: Subterranean well interventionless flow restrictor bypass system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit under 35 USC §119 of the filing date of International Application Serial No. PCT/US12/22043 filed 20 Jan. 2012. The entire disclosure of this prior application is incorporated herein by this reference. 
     BACKGROUND 
     This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in one example described below, more particularly provides a flow restrictor bypass system which does not require intervention into the well. 
     It is frequently desirable to restrict flow into a tubular string from one or more productive zones penetrated by a wellbore. However, it may become desirable at a future date to cease restricting flow into the tubular string, so that flow into the tubular string is relatively unrestricted. 
     For this reason and others, it will be appreciated that improvements are continually needed in the art of variably restricting flow in a subterranean well. 
     SUMMARY 
     In this disclosure, systems and methods are provided which bring improvements to the art of variably restricting flow in a subterranean well. One example is described below in which a bypass flow path around a flow restrictor is opened when it is desired to no longer restrict the flow (or to at least substantially decrease a restriction to the flow). Another example is described below in which the bypass flow path is opened after flow is initially restricted by the flow restrictor. 
     A method of variably restricting flow in a subterranean well is provided to the art by this disclosure. In one example, the method can include resisting flow through a flow path; and then selectively opening a pressure barrier which previously prevented flow through another flow path. The flow paths are configured for parallel flow. 
     A flow restrictor system for use with a subterranean well is also described below. In one example, the system can include at least two flow paths configured for parallel flow, a flow restrictor which resists flow through one flow path, and a pressure barrier which prevents flow through another flow path. The pressure barrier is selectively openable to permit flow through the second flow path. 
     These and other features, advantages and benefits will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the disclosure hereinbelow and the accompanying drawings, in which similar elements are indicated in the various figures using the same reference numbers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a representative partially cross-sectional view of a well system and associated method which can embody principles of this disclosure. 
         FIG. 2  is an enlarged scale representative cross-sectional view of a variable flow restrictor system which may be used in the well system and method of  FIG. 1 . 
         FIG. 3  is a representative cross-sectional view of another example of the variable flow restrictor system. 
         FIG. 4  is a representative cross-sectional view of another example of the variable flow restrictor system. 
         FIG. 5  is a further enlarged scale representative cross-sectional view of the variable flow restrictor system, taken along line  5 - 5  of  FIG. 4 . 
         FIG. 6  is a representative cross-sectional view of another example of the variable flow restrictor system. 
         FIGS. 7-9  are representative cross-sectional views of examples of pressure barriers which may be used in the variable flow restrictor system. 
     
    
    
     DETAILED DESCRIPTION 
     Representatively illustrated in  FIG. 1  is a system  10  for use with a well, and an associated method, which can embody principles of this disclosure. As depicted in  FIG. 1 , a wellbore  12  in the system  10  has a generally vertical uncased section  14  extending downwardly from casing  16 , as well as a generally horizontal uncased section  18  extending through an earth formation  20 . 
     A tubular string  22  (such as a production tubing string) is installed in the wellbore  12 . Interconnected in the tubular string  22  are multiple well screens  24 , variable flow restrictor systems  25  and packers  26 . 
     The packers  26  seal off an annulus  28  formed radially between the tubular string  22  and the wellbore section  18 . In this manner, fluids  30  may be produced from multiple intervals or zones of the formation  20  via isolated portions of the annulus  28  between adjacent pairs of the packers  26 . 
     Positioned between each adjacent pair of the packers  26 , a well screen  24  and a variable flow restrictor system  25  are interconnected in the tubular string  22 . The well screen  24  filters the fluids  30  flowing into the tubular string  22  from the annulus  28 . The variable flow restrictor system  25  initially restricts flow of the fluids  30  into the tubular string  22 . 
     At this point, it should be noted that the well system  10  is illustrated in the drawings and is described herein as merely one example of a wide variety of well systems in which the principles of this disclosure can be utilized. It should be clearly understood that the principles of this disclosure are not limited at all to any of the details of the well system  10 , or components thereof, depicted in the drawings or described herein. 
     For example, it is not necessary in keeping with the principles of this disclosure for the wellbore  12  to include a generally vertical wellbore section  14  or a generally horizontal wellbore section  18 . It is not necessary for fluids  30  to be only produced from the formation  20  since, in other examples, fluids could be injected into a formation, fluids could be both injected into and produced from a formation, etc. 
     It is not necessary for one each of the well screen  24  and variable flow restrictor system  25  to be positioned between each adjacent pair of the packers  26 . It is not necessary for a single variable flow restrictor system  25  to be used in conjunction with a single well screen  24 . Any number, arrangement and/or combination of these components may be used. 
     It is not necessary for any variable flow restrictor system  25  to be used with a well screen  24 . For example, in injection operations, the injected fluid could be flowed through a variable flow restrictor system  25 , without also flowing through a well screen  24 . 
     It is not necessary for the well screens  24 , variable flow restrictor systems  25 , packers  26  or any other components of the tubular string  22  to be positioned in uncased sections  14 ,  18  of the wellbore  12 . Any section of the wellbore  12  may be cased or uncased, and any portion of the tubular string  22  may be positioned in an uncased or cased section of the wellbore, in keeping with the principles of this disclosure. 
     It should be clearly understood, therefore, that this disclosure describes how to make and use certain examples, but the scope of the disclosure is not limited to any details of those examples. Instead, those principles can be applied to a variety of other examples using the knowledge obtained from this disclosure. 
     It will be appreciated by those skilled in the art that it would be beneficial to be able to regulate flow of the fluids  30  into the tubular string  22  from each zone of the formation  20 , for example, to prevent water coning  32  or gas coning  34  in the formation. Other uses for flow regulation in a well include, but are not limited to, balancing production from (or injection into) multiple zones, minimizing production or injection of undesired fluids, maximizing production or injection of desired fluids, etc. 
     Examples of the variable flow restrictor systems  25  described more fully below can provide these benefits by restricting flow (e.g., to thereby balance flow among zones, prevent water or gas coning, restrict flow of an undesired fluid such as water or gas in an oil producing well, etc.). However, when it is no longer desired to restrict the flow of the fluid  30 , one or more parallel bypass flow paths can be opened, so that relatively unrestricted flow of the fluid into (or out of) the tubular string  22  is permitted. 
     Referring additionally now to  FIG. 2 , an enlarged scale cross-sectional view of one example of the variable flow restrictor system  25  is representatively illustrated. In this example, the fluid  30  flows through the screen  24 , and is thereby filtered, prior to flowing into a housing  36  of the system  25 . 
     Secured in the housing  36  are one or more generally tubular flow restrictors  38  which restrict flow of the fluid  30  through the housing. Other types of flow restrictors (such as orifices, tortuous flow paths, vortex chambers, etc.) may be used, if desired. The scope of this disclosure is not limited to any particular type, number or combination of flow restrictors. 
     The flow restrictors  38  form sections of flow paths  40  extending between the annulus  28  on an exterior of the system  25  to an interior flow passage  42  extending longitudinally through a base pipe  44  of the screen  24  and system  25 . The base pipe  44  can be configured for interconnection in the tubular string  22 , in which case the flow passage  42  will extend longitudinally through the tubular string, as well. 
     Pressure barriers  46  close off additional flow paths  48  which are parallel to the flow paths  40 . The flow paths  40 ,  48  are “parallel,” in that they can each be used to conduct the fluid  30  from one place to another, but the fluid does not have to flow through one before it flows through the other (i.e., the flow paths are not in series). 
     In the  FIG. 2  example, one set of the pressure barriers  46  is in the base pipe  44  within the housing  36 , and another set of the pressure barriers is in the base pipe within the screen  24 . However, in practice only one of these sets may be used, and it should be clearly understood that the scope of this disclosure is not limited to any particular location of the pressure barriers  46 . 
     Flow through the flow paths  48  is prevented, until the pressure barriers  46  are opened. Any technique for opening the flow paths  48  may be used (e.g., dissolving or degrading a plug, breaking a plug, oxidizing a pyrotechnic material, opening a valve, etc.). Several ways of opening the flow paths  48  are described below, but it should be clearly understood that the scope of this disclosure is not limited to any particular way of opening the flow paths. 
     When the flow paths  48  are opened, the fluid  30  can flow relatively unrestricted from the screen  24 , through the flow paths, and into the passage  42 . Thus, flow between the interior and the exterior of the system  25  is not restricted substantially by the flow restrictors  38 , although since the flow restrictors are in parallel with the flow paths  48 , there will be some flow through the restrictors. However, this flow through the restrictors  38  will be minimal, because the fluid  30  will tend to flow more through the less restrictive flow paths  48  (e.g., the paths of least resistance). 
     In the  FIG. 2  example, the flow paths  48  are formed through a wall of the base pipe  44 . However, other locations for the flow paths  48  may be used, if desired. 
     In  FIG. 3 , another example of the system  25  is representatively illustrated, in which the flow path  48  comprises an annular space formed between the housing  36  and an outer sleeve  50 . The pressure barriers  46  are positioned in the housing  36 , preventing the fluid  30  from flowing from the screen  24  through the flow path  48 . 
     In  FIGS. 4 &amp; 5 , the pressure barriers  46  are positioned in an upper end of the housing  36 . In this example, the flow paths  40 ,  48  are geometrically parallel (in that they all extend longitudinally in the housing) and are circumferentially offset from each other in the housing  36 . 
     In  FIG. 6 , an example similar in many respects to that of  FIG. 3  is representatively illustrated. In the  FIG. 6  example, a single annular shaped pressure barrier  46  is positioned to block flow through the annular space between the housing  36  and the sleeve  50 . 
     Representatively illustrated in  FIGS. 7-9  are various different types of pressure barriers  46  which may be used in the flow restrictor system  25 . These demonstrate that the scope of this disclosure is not limited to use of any particular type of pressure barrier in the system  25 . 
     In  FIG. 7 , the pressure barrier  46  is in the form of a plug  54  which comprises a dissolvable or otherwise degradable material  52 . For example, aluminum can be dissolved by contact with an acid, polylactic acid can be dissolved by contact with water at an elevated temperature, anhydrous boron can be degraded by contact with water, etc. Any type of dissolvable or degradable material may be used in the plug  54 , as desired. 
     A plug  54  can be dissolved by galvanic action, as described in U.S. Pat. No. 7,699,101, the entire disclosure of which is incorporated herein by this reference. An electrical current may be applied to the plug  54  to quicken or slow the galvanic dissolving of the plug, if desired. 
     In  FIG. 8 , the pressure barrier  46  is in the form of a rupture disk or other frangible barrier  56 . The frangible barrier  56  blocks flow through the flow path  48  until a predetermined pressure differential is applied across the barrier, thereby causing the barrier to break. Any type of frangible barrier may be used, as desired. 
     In  FIG. 9 , the pressure barrier  46  is in the form of a valve  58  which opens when a predetermined signal  60  is transmitted from a transmitter  62  to a receiver or sensor  64  of the system  25 . The signal  60  can be any type of signal (e.g., radio frequency, acoustic, electromagnetic, magnetic, chemical, etc.). 
     The sensor  64  is connected to a controller  66 , which is supplied with electrical power from a power supply  68  (for example, batteries, a downhole generator, etc.). The controller  66  causes the valve  58  to actuate open, in response to the signal  60  being detected by the sensor  64 . 
     Suitable valves for use in the system  25  of  FIG. 9  are described in US Publication No. 2010-0175867, the entire disclosure of which is incorporated herein by this reference. Any type of valve may be used for the pressure barrier  46  in the system  25 , as desired. 
     The transmitter  62  can be conveyed into close proximity to the system  25  by, for example, enclosing the transmitter in a dart, a wireline tool, or another structure  70  dropped, lowered or otherwise displaced through the passage  42  to the system. Alternatively, the signal  60  could be transmitted from a remote location (such as the earth&#39;s surface or another location in the well), if desired. 
     It may now be fully appreciated that the above disclosure provides significant advancements to the art of variably restricting flow in a well. The system  25  described above allows for conveniently changing the resistance to flow through the system (e.g., between the interior and exterior of the system). In examples described above, this change can be made without intervening into the well. However, intervention can be used in other examples, if desired. 
     A method of variably restricting flow in a subterranean well is described above. In one example, the method can include: resisting flow through a first flow path  40 ; and then selectively opening a pressure barrier  46  which previously prevented flow through a second flow path  48 . The first and second flow paths  40 ,  48  are configured for parallel flow. 
     A flow restrictor  38  can permit flow through the first flow path  40 . 
     The first and second flow paths  40 ,  48  may conduct flow between an interior and an exterior of a tubular string  22  in the well. 
     The first and second flow paths  40 ,  48  may receive fluid  30  from a screen  24 . 
     The pressure barrier  46  may comprise a valve  58 , a dissolvable plug  54 , a degradable plug  54  and/or a frangible barrier  56 . 
     The selectively opening can include breaking a frangible barrier  56  in response to application of a predetermined pressure differential. 
     The selectively opening can include dissolving the plug  54  by contacting the plug  54  with acid. 
     The selectively opening can include dissolving the plug  54  by contacting the plug  54  with water at an elevated temperature. 
     The selectively opening can include opening the pressure barrier  46  in response to a signal  60  transmitted to a sensor  64  of the system  25 . The signal  60  can comprise a radio frequency signal. 
     Also described above is a flow restrictor system  25  for use with a subterranean well. The system  25  can include at least first and second flow paths  40 ,  48  configured for parallel flow, a flow restrictor  38  which resists flow through the first flow path  40 , and a pressure barrier  46  which prevents flow through the second flow path  48 . The pressure barrier  46  is selectively openable to permit flow through the second flow path  48 . 
     Although various examples have been described above, with each example having certain features, it should be understood that it is not necessary for a particular feature of one example to be used exclusively with that example. Instead, any of the features described above and/or depicted in the drawings can be combined with any of the examples, in addition to or in substitution for any of the other features of those examples. One example&#39;s features are not mutually exclusive to another example&#39;s features. Instead, the scope of this disclosure encompasses any combination of any of the features. 
     Although each example described above includes a certain combination of features, it should be understood that it is not necessary for all features of an example to be used. Instead, any of the features described above can be used, without any other particular feature or features also being used. 
     It should be understood that the various embodiments described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of this disclosure. The embodiments are described merely as examples of useful applications of the principles of the disclosure, which is not limited to any specific details of these embodiments. 
     In the above description of the representative examples, directional terms (such as “above,” “below,” “upper,” “lower,” etc.) are used for convenience in referring to the accompanying drawings. However, it should be clearly understood that the scope of this disclosure is not limited to any particular directions described herein. 
     The terms “including,” “includes,” “comprising,” “comprises,” and similar terms are used in a non-limiting sense in this specification. For example, if a system, method, apparatus, device, etc., is described as “including” a certain feature or element, the system, method, apparatus, device, etc., can include that feature or element, and can also include other features or elements. Similarly, the term “comprises” is considered to mean “comprises, but is not limited to.” 
     Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the disclosure, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiments, and such changes are contemplated by the principles of this disclosure. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the invention being limited solely by the appended claims and their equivalents.