Patent Publication Number: US-8967267-B2

Title: Fluid discrimination for use with a subterranean well

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 13/659,375 filed on 24 Oct. 2012, which claims the benefit under 35 USC §119 of the filing date of International Application Ser. No. PCT/US11/59534, filed 7 Nov. 2011. The entire disclosures of these prior applications are incorporated herein by this reference. 
    
    
     BACKGROUND 
     This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described herein, more particularly provides for fluid discrimination with well fluids. 
     Among the many reasons for discriminating between fluids are included: a) fluid separation, b) control of produced fluids, c) control over the origin of produced fluids, d) prevention of formation damage, e) conformance, f) control of injected fluids, g) control over which zones receive injected fluids, h) prevention of gas or water coning, i) stimulation, etc. Therefore, it will be appreciated that improvements in the art are continually needed. 
     SUMMARY 
     In this disclosure, systems and methods are provided which bring improvements to the art of discriminating between fluids in conjunction with well operations. One example is described below in which a change in direction of flow of fluids through a fluid discrimination system changes a resistance to the flow. Another example is described below in which a fluid composition is routed to different outlet flow paths by a fluid discriminator, depending on properties, characteristics, etc. of the fluid composition. 
     In one described example, a fluid discrimination system for use with a subterranean well can include a fluid discriminator which selects through which of multiple outlet flow paths a fluid composition flows. The selection can be based on at least one direction of flow of the fluid composition through the fluid discriminator. The direction may be dependent on at least one fluid type in the fluid composition. 
     In another example, a fluid discriminator can include a structure which displaces in response to a flow of a fluid composition. An outlet flow path of a majority of the fluid composition may change in response to a change in a ratio of fluids in the fluid composition. 
     In a further example, a method of discriminating between fluids flowed in a subterranean well can include providing a fluid discriminator which selects through which of multiple outlet flow paths a fluid composition flows in the well. The fluid discriminator can perform the selection based on a direction of flow of the fluid composition through the fluid discriminator, which direction can be dependent on a ratio of the fluids in the fluid composition. 
     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 below 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 system and associated method which can embody principles of this disclosure. 
         FIG. 2  is a representative cross-sectional view of a fluid discrimination system which can embody the principles of this disclosure. 
         FIG. 3  is a representative cross-sectional view of the fluid discrimination system, taken along line  3 - 3  of  FIG. 2 . 
         FIG. 4  is a representative cross-sectional view of a fluid discriminator which can embody the principles of this disclosure. 
         FIGS. 5 &amp; 6  are representative cross-sectional views of the fluid discriminator, taken along line  5 - 5  of  FIG. 4 , a fluid composition being directed to different outlet flow paths in  FIGS. 5 &amp; 6 . 
         FIGS. 7 &amp; 8  are representative cross-sectional views of another configuration of the fluid discriminator, a fluid composition being directed to different outlet flow paths in  FIGS. 7 &amp; 8 . 
         FIG. 9  is a representative cross-sectional view of another configuration of the fluid discriminator. 
         FIG. 10  is a representative cross-sectional view of the fluid discriminator, taken along line  10 - 10  of  FIG. 9 . 
         FIG. 11  is a representative cross-sectional view of a fluid switch which may be used in the fluid discriminator. 
         FIG. 12  is a representative cross-sectional view of another configuration of the fluid switch. 
         FIGS. 13 &amp; 14  are representative cross-sectional views of another configuration of the fluid discriminator,  FIG. 13  being taken along line  13 - 13  of  FIG. 14 . 
         FIGS. 15 &amp; 16  are representative cross-sectional views of another configuration of the fluid discriminator,  FIG. 16  being taken along line  16 - 16  of  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION 
     Representatively illustrated in  FIG. 1  is a system  10  for use with a well, which system can embody principles of this disclosure. As depicted in  FIG. 1 , a wellbore  12  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 , fluid discrimination 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 fluid discrimination 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 fluid discrimination system  25  discriminates between the fluids  30  that are flowed into the tubular string  22 , based on certain characteristics of the fluids. 
     At this point, it should be noted that the system  10  is illustrated in the drawings and is described herein as merely one example of a wide variety of 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 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 fluid discrimination system  25  to be positioned between each adjacent pair of the packers  26 . It is not necessary for a single fluid discrimination 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 fluid discrimination system  25  to be used with a well screen  24 . For example, in injection operations, the injected fluid could be flowed through a fluid discrimination system  25 , without also flowing through a well screen  24 . 
     It is not necessary for the well screens  24 , fluid discrimination 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 principles of the disclosure are 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, transmitting signals, etc. 
     In certain examples described below, resistance to flow through the systems  25  can be selectively varied, on demand and/or in response to a particular condition. For example, flow through the systems  25  could be relatively restricted while the tubular string  22  is installed, and during a gravel packing operation, but flow through the systems could be relatively unrestricted when producing the fluid  30  from the formation  20 . As another example, flow through the systems  25  could be relatively restricted at elevated temperature indicative of steam breakthrough in a steam flooding operation, but flow through the systems could be relatively unrestricted at reduced temperatures. 
     An example of the fluid discrimination systems  25  described more fully below can also increase resistance to flow if a fluid velocity or density increases (e.g., to thereby balance flow among zones, prevent water or gas coning, etc.), or increase resistance to flow if a fluid viscosity decreases (e.g., to thereby restrict flow of an undesired fluid, such as water or gas, in an oil producing well). Conversely, these fluid discrimination systems  25  can decrease resistance to flow if fluid velocity or density decreases, or if fluid viscosity increases. 
     Whether a fluid is a desired or an undesired fluid depends on the purpose of the production or injection operation being conducted. For example, if it is desired to produce oil from a well, but not to produce water or gas, then oil is a desired fluid and water and gas are undesired fluids. If it is desired to inject steam instead of water, then steam is a desired fluid and water is an undesired fluid. If it is desired to produce hydrocarbon gas and not water, then hydrocarbon gas is a desired fluid and water is an undesired fluid. 
     Note that, at downhole temperatures and pressures, hydrocarbon gas can actually be completely or partially in liquid phase. Thus, it should be understood that when the term “gas” is used herein, supercritical, liquid and/or gaseous phases are included within the scope of that term. 
     In other examples, a fluid discriminator of the system  25  can be used to separate fluids in the fluid composition  36  (for example, to flow different fluid types to respective different processing facilities, to produce only certain fluid type(s), to inject only certain fluid type(s), etc.). Thus, it should be understood that the fluid discriminator may be used for any purpose, and is not necessarily used for variably resisting flow, in keeping with the scope of this disclosure. 
     Referring additionally now to  FIG. 2 , an enlarged scale cross-sectional view of one of the fluid discrimination systems  25 , and a portion of one of the well screens  24 , is representatively illustrated. In this example, a fluid composition  36  (which can include one or more fluid types, such as oil and water, liquid water and steam, oil and gas, gas and water, oil, water and gas, etc.) flows into the well screen  24 , is thereby filtered, and then flows into an inlet  38  of the fluid discrimination system  25 . 
     A fluid composition can include one or more undesired or desired fluids. Both steam and liquid water can be combined in a fluid composition. As another example, oil, water and/or gas can be combined in a fluid composition. 
     Flow of the fluid composition  36  through the fluid discrimination system  25  is resisted based on one or more characteristics (such as flow direction, viscosity, velocity, density, etc.) of the fluid composition. The fluid composition  36  is then discharged from the fluid discrimination system  25  to an interior of the tubular string  22  via an outlet  40 . 
     In other examples, the well screen  24  may not be used in conjunction with the fluid discrimination system  25  (e.g., in injection operations), the fluid composition  36  could flow in an opposite direction through the various elements of the well system  10  (e.g., in injection operations), a single fluid discrimination system could be used in conjunction with multiple well screens, multiple fluid discrimination systems could be used with one or more well screens, the fluid composition could be received from or discharged into regions of a well other than an annulus or a tubular string, the fluid composition could flow through the fluid discrimination system prior to flowing through the well screen, any other components could be interconnected upstream or downstream of the well screen and/or fluid discrimination system, etc. Thus, it will be appreciated that the principles of this disclosure are not limited at all to the details of the example depicted in  FIG. 2  and described herein. 
     Although the well screen  24  depicted in  FIG. 2  is of the type known to those skilled in the art as a wire-wrapped well screen, any other types or combinations of well screens (such as sintered, expanded, pre-packed, wire mesh, etc.) may be used in other examples. Additional components (such as shrouds, shunt tubes, lines, instrumentation, sensors, inflow control devices, etc.) may also be used, if desired. 
     The fluid discrimination system  25  is depicted in simplified form in  FIG. 2 , but in a preferred example, the system can include various passages and devices for performing various functions, some examples of which are described more fully below. In addition, the system  25  preferably at least partially extends circumferentially about the tubular string  22 , or the system may be formed in a wall of a tubular structure interconnected as part of the tubular string. 
     In other examples, the system  25  may not extend circumferentially about a tubular string or be formed in a wall of a tubular structure. For example, the system  25  could be formed in a flat structure, etc. The system  25  could be in a separate housing that is attached to the tubular string  22 , or it could be oriented so that the axis of the outlet  40  is parallel to the axis of the tubular string. The system  25  could be on a logging string or attached to a device that is not tubular in shape. Any orientation or configuration of the system  25  may be used in keeping with the principles of this disclosure. 
     Referring additionally now to  FIG. 3 , a cross-sectional view of the fluid discrimination system  25 , taken along line  3 - 3  of  FIG. 2 , is representatively illustrated. The fluid discrimination system  25  example depicted in  FIG. 3  may be used in the well system  10  of  FIGS. 1 &amp; 2 , or it may be used in other well systems in keeping with the principles of this disclosure. 
     In  FIG. 3 , it may be seen that the fluid composition  36  flows from the inlet  38  to the outlet  40  via inlet flow path  44 , a fluid discriminator  42 , outlet flow paths  46 ,  48  and a flow chamber  50 . The outlet flow paths  46 ,  48  intersect the chamber  50  at inlets  52 ,  54 . 
     The outlet flow path  46  intersects the chamber  50  in a generally radial direction relative to the chamber and outlet  40 . The outlet flow path  48 , however, intersects the chamber  50  generally tangentially. Thus, flow entering the chamber  50  from the inlet  52  is in a generally radial direction, and flow entering the chamber from the inlet  54  is in a generally tangential direction. The tangential flow from the inlet  54  is guided to rotational flow by an outer wall of the chamber  50 . 
     It will be appreciated that the indirect rotational flow from the inlet  54  to the outlet  40  dissipates more energy as compared to the relatively direct radial flow from the inlet  52  to the outlet  40 . Therefore, rotational (including, e.g., spiral, helical, etc.) flow is resisted more by the system  25  than is radial flow of the fluid composition  36  through the chamber  50 . 
     The fluid discriminator  42 , in this example, discriminates between various fluid types in the fluid composition  36 , or between ratios of desired to undesired fluids in the fluid composition, so that a fluid composition  36   a  having one fluid type, level of fluid type, ratio of desired to undesired fluid, etc., is directed to flow through the outlet flow path  46  to the chamber inlet  52 , and another fluid composition  36   b  having a different fluid type, different level of fluid type, different ratio of desired to undesired fluid, etc., is directed to flow through the other outlet flow path  48  to the chamber inlet  54 . Thus, the resistance to flow of the fluid composition  36  through the system  25  can be varied based on the fluid type(s) or the ratio of desired to undesired fluid in the fluid composition. 
     For example, the fluid discriminator  42  can cause more of the fluid composition  36  to flow through the outlet flow path  46  (thereby decreasing resistance to such flow) when the ratio of desired to undesired fluid increases, or when a certain desired fluid type or proportion of fluid type is present in the fluid composition, and the fluid discriminator can cause more of the fluid composition to flow through the outlet flow path  48  (thereby increasing resistance to such flow) when the ratio of desired to undesired fluid decreases, or when a certain desired fluid type or proportion of fluid type is not present in the fluid composition. 
     Referring additionally now to  FIGS. 4-6 , one example of the fluid discriminator  42  is representatively illustrated. The fluid discriminator  42  may be used in the fluid discrimination system  25  and well system  10  described above, or the fluid discriminator may be used with other systems in keeping with the scope of this disclosure. 
     The configuration of  FIGS. 4-6  includes a structure  58  which displaces in response to a change in a proportion of the fluid composition  36  which flows through inlet flow paths  44   a,b  (that is, a ratio of the fluid composition which flows through one inlet flow path and the fluid composition which flows through the other inlet flow path). 
     For example, in  FIG. 5 , a majority of the fluid composition  36   b  flows via the flow path  44   b , and this flow impinging on the structure  58  causes the structure to displace to a position in which such flow is directed to the outlet flow path  48 . Note that, in  FIG. 5 , the structure  58  and a beam  62  extending between the structure and a connection  60  substantially block the fluid composition  36   b  from flowing to the outlet flow path  46 . 
     In  FIG. 6 , a majority of the fluid composition  36   a  flows via the flow path  44   a  and, in response, the structure  58  displaces to a position in which such flow is directed to the outlet flow path  46 . The structure  58  and the beam  62  substantially block the fluid composition  36   a  from flowing to the outlet flow path  48 . 
     In other examples, the structure  58  or beam  62  may not block the flow of the fluid composition  36  (e.g., another member or structure may be used to block such flow), and the structure could be biased toward the  FIG. 5  and/or  FIG. 6  position (e.g., using springs, compressed gas, other biasing devices, etc.), thereby changing the proportion of the fluid composition  36  which must flow through a particular flow path  44   a,b  in order to displace the structure. Preferably, the fluid composition  36  does not have to exclusively flow through only one of the flow paths  44   a,b  in order to displace the structure  58  to a particular position, but such a design could be implemented, if desired. 
     The structure  58  is mounted via the connection  60 . Preferably, the connection  60  serves to secure the structure  58 , and also to resist a pressure differential applied across the structure from the flow paths  44   a,b  to the outlet flow paths  46 ,  48 . When the fluid composition  36  is flowing through the system  25 , this pressure differential can exist, and the connection  60  can resist the resulting forces applied to the structure  58 , while still permitting the structure to displace freely in response to a change in the proportion of the flow via the flow paths  44   a,b.    
     In the  FIGS. 5 &amp; 6  example, the connection  60  is depicted as a pivoting or rotational connection. However, in other examples, the connection  60  could be a rigid, sliding, translating, or other type of connection, thereby allowing for displacement of the structure  58  in any of circumferential, axial, longitudinal, lateral, radial, etc., directions. 
     In one example, the connection  60  could be a rigid connection, with a flexible beam  62  extending between the connection and the structure  58 . The beam  62  could flex, instead of the connection  60  rotating, in order to allow the structure  58  to displace, and to provide a biasing force toward the position of  FIG. 5 , toward the position of  FIG. 6 , or toward any other position (e.g., a position between the  FIGS. 5 &amp; 6  positions, etc.). 
     The  FIGS. 4-6  configuration utilizes a fluid switch  66  with multiple control passages  68 ,  70 . The fluid switch  66  directs the fluid composition  36  flow toward the flow path  44   a  when flow  72  through the control passage  68  is toward the fluid switch, and/or when flow  74  in the control passage  70  is away from the fluid switch. The fluid switch  66  directs the fluid composition  36  flow toward the flow path  44   b  when flow  72  through the control passage  68  is away from the fluid switch, and/or when flow  74  in the control passage  70  is toward the fluid switch. 
     Thus, since the proportion of the fluid composition  36  which flows through the flow paths  44   a,b  can be changed by the fluid switch  66 , in response to the flows  72 ,  74  through the control passages  68 ,  70 , it follows that the resistance to flow of the fluid composition  36  through the system  25  can be changed by changing the flows through the control passages. For this purpose, the control passages  68 ,  70  may be connected to any of a variety of devices for influencing the flows  72 ,  74  through the control passages. 
     The flows  72 ,  74  through the control passages  68 ,  70  could be automatically changed in response to changes in one or more properties (such as density, viscosity, velocity, etc.) of the fluid composition  36 , the flows could be controlled locally (e.g., in response to sensor measurements, etc.), or the flows could be controlled remotely (e.g., from the earth&#39;s surface, another remote location, etc.). Any technique for controlling the flows  72 ,  74  through the control passages  68 ,  70  may be used, in keeping with the scope of this disclosure. 
     Preferably, the flow  72  is toward the fluid switch  66 , and/or the flow  74  is away from the fluid switch, when the fluid composition  36  has an increased ratio of desired to undesired fluids, or a certain proportion of a desired fluid type, so that more of the fluid composition will be directed by the fluid switch to flow toward the flow path  44   a , thereby reducing the resistance to flow through the system  25 . Conversely, the flow  72  is preferably away from the fluid switch  66 , and/or the flow  74  is preferably toward the fluid switch, when the fluid composition  36  has a decreased ratio of desired to undesired fluids, or less than a threshold level of a desired fluid type, so that more of the fluid composition will be directed by the fluid switch to flow toward the flow path  44   b , thereby increasing the resistance to flow through the system  25 . 
     In other examples, the outlet flow paths  46 ,  48  could be connected to separate processing facilities for the different fluid types in the fluid composition  36 , or the outlet flow paths could be connected to different production or injection equipment, etc. Thus, it should be understood that it is not necessary in keeping with the scope of this disclosure for the system  25  to variably resist flow of the fluid composition  36  from the fluid discriminator  42 . 
     Referring additionally now to  FIGS. 7 &amp; 8 , another configuration of the fluid discriminator  42  is representatively illustrated. In this configuration, the structure  58  rotates about the connection  60 , in order to direct flow more toward the outlet flow path  46  ( FIG. 7 ) or more toward the outlet flow path  48  ( FIG. 8 ). 
     As in the configuration of  FIGS. 4-6 , the configuration of  FIGS. 7 &amp; 8  has the structure  58  exposed to flow in both of the flow paths  44   a,b . Depending on a proportion of these flows, the structure  58  can displace to either of the  FIGS. 7 &amp; 8  positions (or to any position in-between those positions). The structure  58  in the  FIGS. 4-8  configurations can be biased toward any position, or releasably retained at any position, in order to adjust the proportion of flows through the flow paths  44   a,b  needed to displace the structure to another position. 
     Referring additionally now to  FIGS. 9 &amp; 10 , another configuration of the fluid discriminator  42  is representatively illustrated. In this configuration, the structure  58  is positioned in a chamber  64  connected to the flow paths  46 ,  48 . 
     In the  FIGS. 9 &amp; 10  example, a majority of the flow of the fluid composition  36  through the flow path  44   a  results in the structure  58  rotating about the connection  60  to a position in which flow is directed to the outlet flow path  46 . However, if a majority of the flow is through the flow path  44   b  to the chamber  64  (as depicted in  FIG. 9 ), the structure  58  will rotate to a position in which the flow is directed to the outlet flow path  48 . 
     The structure  58  in this example rotates about the connection  60  in response to rotational flow of the fluid composition  36  in the chamber  64 . The direction of this rotational flow determines the direction of rotation of the structure  58 , and thus determines whether more of the fluid composition  36  will exit the chamber  64  via the flow path  46  or the flow path  48 . 
     Referring additionally now to  FIGS. 11 &amp; 12 , additional configurations of the fluid switch  66  are representatively illustrated. The fluid switch  66  in these configurations has a blocking device  76  which rotates about a connection  78  to increasingly block flow through one of the inlet flow paths  44   a,b  when the fluid switch directs the flow toward the other flow path. These fluid switch  66  configurations may be used in any fluid discriminator  42  configuration. 
     In the  FIG. 11  example, either or both of the control passage flows  72 ,  74  influence the fluid composition  36  to flow toward the flow path  44   a . Due to this flow toward the flow path  44   a  impinging on the blocking device  76 , the blocking device rotates to a position in which the other flow path  44   b  is completely or partially blocked, thereby influencing an even greater proportion of the fluid composition to flow via the flow path  44   a , and not via the flow path  44   b . However, if either or both of the control passage flows  72 ,  74  influence the fluid composition  36  to flow toward the flow path  44   b , this flow impinging on the blocking device  76  will rotate the blocking device to a position in which the other flow path  44   a  is completely or partially blocked, thereby influencing an even greater proportion of the fluid composition to flow via the flow path  44   b , and not via the flow path  44   a.    
     In the  FIG. 12  example, either or both of the control passage flows  72 ,  74  influence the blocking device  76  to increasingly block one of the flow paths  44   a,b . Thus, an increased proportion of the fluid composition  36  will flow through the flow path  44   a,b  which is less blocked by the device  76 . When either or both of the flows  72 ,  74  influence the blocking device  76  to increasingly block the flow path  44   a , the blocking device rotates to a position in which the other flow path  44   b  is not blocked, thereby influencing a greater proportion of the fluid composition to flow via the flow path  44   b , and not via the flow path  44   a . However, if either or both of the control passage flows  72 ,  74  influence the blocking device  76  to rotate toward the flow path  44   b , the other flow path  44   a  will not be blocked, and a greater proportion of the fluid composition  36  will flow via the flow path  44   a , and not via the flow path  44   b.    
     By increasing the proportion of the fluid composition  36  which flows through the flow path  44   a  or  44   b , operation of the fluid discriminator  42  is made more efficient. For example, resistance to flow through the system  25  can be readily increased when an unacceptably low ratio of desired to undesired fluids exists in the fluid composition  36 , and resistance to flow through the system can be readily decreased when the fluid composition has a relatively high ratio of desired to undesired fluids. 
     In other examples, separation of fluid types can be made more efficient by increasing the proportion of the fluid composition  36  which flows through either the flow path  44   a  or the flow path  44   b . The separated fluid types could be flowed to separate processing facilities, one fluid type could be produced, another fluid type could be injected into the formation  20  or another formation, etc. 
     Referring additionally now to  FIGS. 13 &amp; 14 , another configuration of the fluid discriminator  42  is representatively illustrated. This configuration is similar in some respects to the configuration of  FIGS. 9 &amp; 10 , in that the structure  58  rotates in the chamber  64  in order to change the outlet flow path  46 ,  48 . The direction of rotation of the structure  58  depends on through which of the flow paths  44   a  or  44   b  a greater proportion of the fluid composition  36  flows. 
     In the  FIGS. 13 &amp; 14  example, the structure  58  includes vanes  80  on which the fluid composition  36  impinges. Thus, rotational flow in the chamber  64  impinges on the vanes  80  and biases the structure  58  to rotate in the chamber. 
     When the structure  58  is in the position depicted in  FIGS. 13 &amp; 14 , openings  82  align with openings  84 , the structure substantially blocks flow from the chamber  64  to the outlet flow path  48 , and the structure does not substantially block flow from the chamber  64  to the outlet flow path  46 . However, if the structure  58  rotates to a position in which the openings  82 ,  86  are aligned, then the structure will not substantially block flow from the chamber  64  to the outlet flow path  48 , and the structure will substantially block flow from the chamber  64  to the outlet flow path  46 . 
     Referring additionally now to  FIGS. 15 &amp; 16 , another configuration of the fluid discrimination system  25  is representatively illustrated. In this configuration, the fluid discriminator  42  is downstream of the chamber  50 , thus, the fluid discriminator receives the fluid composition  36  which flows through the outlet  40 . The fluid composition  36  flows more toward the outlet flow path  46  or  48 , depending on whether the fluid composition flows directly or rotationally through the outlet  40 . 
     In this example, the chamber  50  has only the inlet  52  through which the fluid composition  36  flows into the chamber. However, in other examples, multiple inlets (such as the multiple inlets  52 ,  54  of  FIG. 3 ) could be used. 
     As depicted in  FIG. 15 , the fluid composition  36   a  (e.g., which can have a relatively low velocity, a relatively low density, a relatively high viscosity, a relatively high ratio of desired to undesired fluid, and/or a certain proportion of a desired fluid type, etc.) can flow directly radially toward the outlet  40  from the inlet  52 , and so such flow has only minimal or no rotational direction to it. However, the fluid composition  36   b  (e.g., which can have a relatively high velocity, a relatively high density, a relatively low viscosity, a relatively low ratio of desired to undesired fluid, and/or less than a certain proportion of a desired fluid type, etc.) flows rotationally about the chamber  50  and the outlet  40  from the inlet  52 . 
     As depicted in  FIG. 16 , the flow of the fluid composition  36   a  enters the outlet  40  from a radial direction, and flows directly into the outlet flow passage  46 , an inlet  86  of which is positioned centrally with respect to the outlet  40  and within another chamber  88 . The fluid composition  36   b , however, flows rotationally through the outlet  40 . The rotational momentum of the fluid composition  36   b  causes it to flow outward toward an outer wall of the chamber  88  as the fluid composition enters the chamber  88  via the outlet  40 . The outlet flow path  48  receives the fluid composition  36   b  which flows along the walls of the chamber  88 , but the outlet flow path  46  receives the fluid composition  36   a  which flows from the outlet  40  to the centrally located inlet  86 . 
     Note that, although in certain examples described above, the two fluid compositions  36   a,b  may be depicted in a same drawing figure, this does not necessarily require that the fluid compositions  36   a,b  flow through the system  25  at the same time. Instead, the fluid composition  36  can at some times have the properties, characteristics, etc., of the fluid composition  36   a  (e.g., with a relatively low velocity, a relatively low density, a relatively high viscosity, a relatively high ratio of desired to undesired fluid, and/or a certain proportion of a desired fluid type, etc.), and the fluid composition  36  can at other times have the properties, characteristics, etc., of the fluid composition  36   b  (e.g., with a relatively high velocity, a relatively high density, a relatively low viscosity, a relatively low ratio of desired to undesired fluid, and/or less than a certain proportion of a desired fluid type, etc.). The fluid compositions  36   a,b  are depicted as merely two examples of the fluid composition  36 , for illustration of how the fluid composition can flow differently through the system  25  based on different properties, characteristics, etc. of the fluid composition. 
     Although in certain examples described above, the structure  58  displaces by pivoting or rotating, it will be appreciated that the structure could be suitably designed to displace in any direction to thereby change the flow direction through the system  25 . In various examples, the structure  58  could displace in circumferential, axial, longitudinal, lateral and/or radial directions. 
     Although in the examples described above only two outlet flow paths  46 ,  48  and two inlet flow paths  44   a,b  are used, it should be understood that the fluid discriminator  42  could be configured to utilize any number of outlet or inlet flow paths. 
     It may now be fully appreciated that this disclosure provides significant advancements to the art of discriminating between fluids in conjunction with well operations. In multiple examples described above, the fluid composition  36  can be directed to flow to different outlet flow paths  46 ,  48 , depending on different properties, characteristics, etc. of fluids in the fluid composition. 
     In one example, a fluid discrimination system  25  for use with a subterranean well is described above. The system  25  can include a fluid discriminator  42  which selects through which of multiple outlet flow paths  46 ,  48  a fluid composition  36  flows, the selection being based on at least one direction of flow of the fluid composition  36  through the fluid discriminator  42 , and the direction being dependent on at least one fluid type in the fluid composition  36 . 
     The fluid discriminator  42  may select a first outlet flow path  46  in response an increase in a ratio of desired to undesired fluid in the fluid composition  36 , and the fluid discriminator  42  may select a second outlet flow path  48  in response to a decrease in the ratio of desired to undesired fluid. 
     The fluid discriminator  42  may select a first outlet flow path  46  in response to the direction of flow being more radial, and the fluid discriminator  42  may select a second outlet flow path  48  in response to the direction of flow being more rotational. 
     The at least one direction can comprise opposite directions. 
     The at least one direction can comprise first and second directions. The fluid discriminator  42  can select a first outlet flow path  46  in response to flow of the fluid composition  36  more in the first direction, and the fluid discriminator  42  can select a second outlet flow path  48  in response to flow of the fluid composition  36  more in the second direction. 
     The flow of the fluid composition  36  in the first direction may impinge on a structure  58 , whereby the structure  58  displaces and the first outlet flow path  46  is selected. The flow of the fluid composition  36  in the second direction may impinge on the structure  58 , whereby the structure  58  displaces and the second outlet flow path  48  is selected. The structure  58  may rotate in response to the impingement of the fluid composition  36  on the structure  58 . 
     A fluid switch  66  may select in which of the first and second directions the fluid composition  36  flows. The fluid switch  66  may direct the fluid composition  36  to flow more in the first direction in response to an increase in a ratio of desired to undesired fluid, and the fluid switch  66  may direct the fluid composition  36  to flow more in the second direction in response to a decrease in the ratio of desired to undesired fluid. 
     The first direction may be a radial direction. The second direction may be rotational. 
     Also described above is a fluid discriminator for use with a subterranean well. In one example, the fluid discriminator  42  can include a structure  58  which displaces in response to a flow of a fluid composition  36 , whereby an outlet flow path  46 ,  48  of a majority of the fluid composition  36  changes in response to a change in a ratio of fluids in the fluid composition  36 . 
     The structure  58  can be exposed to the flow of the fluid composition  36  in at least first and second directions. The outlet flow path  46 ,  48  can change in response to a change in a proportion of the fluid composition  36  which flows in the first and second directions. 
     The structure  58  may be more biased in a first direction by the flow of the fluid composition  36  more in the first direction, and the structure  58  may be more biased in a second direction by the flow of the fluid composition  36  more in the second direction. 
     The first direction may be opposite to the second direction. The first and second directions can comprise at least one of circumferential, axial, longitudinal, lateral, and/or radial directions. 
     The fluid discriminator  42  can also include a fluid switch  66  which directs the flow of the fluid composition  36  to at least first and second inlet flow paths  44   a,b.    
     The structure  58  may be more biased in a first direction by the flow of the fluid composition  36  more through the first inlet flow path  44   a , and the structure  58  may be more biased in a second direction by the flow of the fluid composition  36  more through the second inlet flow path  44   b.    
     The structure  58  may pivot or rotate, and thereby change the outlet flow path  46 ,  48 , in response to a change in a proportion of the fluid composition  36  which flows through the first and second inlet flow paths  44   a,b . The structure  58  may rotate, and thereby change the outlet flow path  46 ,  48 , in response to a change in a ratio of desired to undesired fluids. 
     The fluid switch  66  may comprise a blocking device  76  which at least partially blocks the flow of the fluid composition  36  through at least one of the first and second inlet flow paths  44   a,b . The blocking device  76  can increasingly block one of the first and second inlet flow paths  44   a,b , in response to the flow of the fluid composition  36  toward the other of the first and second inlet flow paths  44   a,b . The fluid switch  66  may direct the flow of the fluid composition  36  toward one of the first and second inlet flow paths  44   a,b  in response to the blocking device  76  increasingly blocking the other of the first and second inlet flow paths  44   a,b.    
     A method of discriminating between fluids flowed in a subterranean well is also described above. In one example, the method can include providing a fluid discriminator  42  which selects through which of multiple outlet flow paths  46 ,  48  a fluid composition  36  flows in the well, the selection being based on at least one direction of flow of the fluid composition  36  through the fluid discriminator  42 , and the direction being dependent on a ratio of the fluids in the fluid composition  36 . 
     The fluid discriminator  42  may select a first outlet flow path  46  in response an increase in the ratio of fluids, and the fluid discriminator  42  may select a second outlet flow path  48  in response to a decrease in the ratio of fluids. 
     The fluid discriminator  42  may select a first outlet flow path  46  in response to the direction of flow being more radial, and the fluid discriminator  42  may select a second outlet flow path  48  in response to the direction of flow being more rotational. 
     The at least one direction can comprise first and second directions. The fluid discriminator  42  can select a first outlet flow path  46  in response to flow of the fluid composition  36  more in the first direction, and the fluid discriminator  42  can select a second outlet flow path  48  in response to flow of the fluid composition  36  more in the second direction. 
     The flow of the fluid composition  36  in the first direction may impinge on a structure  58 , whereby the structure  58  displaces and the first outlet flow path  46  is selected. The flow of the fluid composition  36  in the second direction may impinge on the structure  58 , whereby the structure  58  displaces and the second outlet flow path  48  is selected. The structure  58  can rotate in response to the impingement of the fluid composition  36  on the structure  58 . 
     A fluid switch  66  may select in which of the first and second directions the fluid composition  36  flows. The fluid switch  66  may direct the fluid composition  36  to flow more in the first direction in response to an increase in the ratio of fluids, and the fluid switch  66  may direct the fluid composition  36  to flow more in the second direction in response to a decrease in the ratio of fluids. 
     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 additional features or elements (the same as or different from the named feature or element). 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.