Patent Publication Number: US-10316647-B2

Title: Regulation of flow through a well tool spring

Description:
TECHNICAL FIELD 
     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 for regulation of flow through a well tool string. 
     BACKGROUND 
     Recent advances in casing/liner rotational orientation in a well allow for pressure pulse telemetry to communicate orientation data to surface via encoded negative pressure pulses. However, a pressure differential is needed between an interior and an exterior of the casing/liner in order to produce the pressure pulses. For this reason and others, advancements are continually needed in the art of regulating flow through a well tool string. Such advancements may be useful whether or not a casing/liner is rotationally oriented using pressure pulse telemetry to encode orientation data on negative pressure pulses. 
    
    
     
       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 flow restriction tool that may be used in the system and method of  FIG. 1 , and which can embody the principles of this disclosure. 
         FIG. 3  is a representative cross-sectional view of the flow restriction tool in an increased flow area configuration thereof. 
     
    
    
     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. However, it should be clearly understood that the system  10  and method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible. Therefore, the scope of this disclosure is not limited at all to the details of the system  10  and method described herein and/or depicted in the drawings. 
     In the  FIG. 1  example, a well tool string  12  is being positioned in a wellbore  14 . The well tool string  12  is part of a casing or liner string  16  that forms a protective lining for the wellbore  14 . 
     The tool string  12  in this example includes an orientation tool  18 , a window joint  20  and a flow restriction tool  22 . The orientation tool  18  and the flow restriction tool  22  are used to rotationally or azimuthally orient a pre-formed window  24  of the window joint  20 , so that a branch or lateral wellbore  26  can be drilled in a desired direction through the window. In this example, the window  24  is closed off (for example, using a relatively easily drilled or milled through material, such as aluminum and/or composite material, etc.) prior to the lateral wellbore  26  being drilled. 
     As depicted in  FIG. 1 , the main or parent wellbore  14  is vertical and the branch or lateral wellbore  26  is inclined or deviated from vertical. However, in other examples, the wellbore  14  could be horizontal or inclined, and/or the wellbore  26  could be horizontal or vertical. The wellbore  14  could be a branch or lateral of another wellbore (not shown). Therefore, it should be clearly understood that the scope of this disclosure is not limited to any of the particular details of the system  10  and method as depicted in  FIG. 1  or described herein. 
     The orientation tool  18  can be of the type that selectively permits and prevents flow through a wall  28  of the tool, to thereby produce pressure pulses  30  in a flow passage  32  extending longitudinally through the casing or liner string  16 . Such pressure pulses  30  can be encoded with orientation data, and can be detected at a remote location (for example, at a surface location using a pressure sensor). 
     The orientation data can be decoded from the detected pressure pulses  30  at the remote location, thereby enabling personnel to verify whether the window  24  is in a desired orientation, or to determine how the casing or liner string  16  should be rotated in order to achieve the desired orientation. This decoding can be performed in real time (as the string  16  is being installed). 
     The orientation tool  18  in the  FIG. 1  example includes an orientation sensor  34  (such as, a gyroscope, three-axis accelerometers, a gravity sensor, etc.), a controller/actuator  36  and a valve  38 . The controller/actuator  36  operates the valve  38  in response to measurements made by the orientation sensor  34 , so that the measurements (orientation data) are encoded on the pressure pulses  30 . 
     In the  FIG. 1  example, the pressure pulses  30  are negative pressure pulses, in that they comprise relatively short decreases in fluid pressure in the flow passage  32 . The fluid pressure in the flow passage  32  is decreased by opening the valve  38 , thereby allowing fluid flow  40  outward through an opening  42  in the wall  28  of the orientation tool  18 . 
     A suitable orientation tool for use in the system  10  is a Casing Orientation Tool (COT) marketed by Intelligent Well Controls of Aberdeen, United Kingdom. However, other orientation tools can be used without departing from the principles of this disclosure. 
     In order for opening of the valve  38  to produce a sufficient decrease in fluid pressure in the flow passage  32  to be detected at the remote location, the fluid pressure in the flow passage should be sufficiently greater than fluid pressure external to the string  16 . For this purpose, the tool string  12  includes the flow restriction tool  22  positioned downstream (with respect to the flow  40 ) from the orientation tool  18 . 
     Although the flow restriction tool  22  is depicted in  FIG. 1  as being opposite the window joint  20  from the orientation tool  18 , in other examples the flow restriction tool could be between the orientation tool and the window joint, the flow restriction tool could be combined with the orientation tool and/or the window joint, etc. Thus, the scope of this disclosure is not limited to any particular arrangement, configuration or construction of the various elements of the well tool string  12 . 
     The flow restriction tool  22  restricts the flow  40  to thereby increase pressure in the flow passage  32  upstream of the flow restriction tool. After passing through the flow restriction tool  22 , the flow  40  exits a bottom (not shown) of the string  16  and returns to the surface via an annulus  44  formed between the string and the wellbore  14 . 
     When the string  16  is properly oriented in the wellbore  14  (e.g., with the window  24  facing in a direction toward the desired lateral wellbore  26 ), it is desired to cement the string in the wellbore  14 . During the cementing operation, flow through the passage  32  is preferably not substantially restricted, since it is not required to maintain a pressure differential from an interior to an exterior of the string  16 . In addition, greater flow area through the flow restriction tool  22  is desirable during the cementing operation, so that the cement can be expeditiously placed where intended. 
     For this purpose (to reduce restriction to flow), the flow restriction tool  22  is capable of increasing a flow area through a variable flow restrictor  46  of the tool, in response to an increase in flow rate. In addition, the variable flow restrictor  46  can be reset so that, if the flow rate is subsequently decreased, the restriction to flow will again be increased. This prevents inadvertent (or even intentional) flow rate increases prior to or during the orienting operation from irreversibly reducing the restriction to flow through the flow restriction tool  22 . 
     In addition, the variable flow restrictor  46  can be made of relatively easily drillable materials (such as, aluminum, composite materials, etc.). In this manner, after the cementing operation is concluded, the flow restriction tool  22  can conveniently be drilled through. 
     Referring additionally now to  FIGS. 2 &amp; 3 , more detailed enlarged scale cross-sectional views of the flow restriction tool  22  are representatively illustrated. The flow restriction tool  22  may be used in the system  10  and method of  FIG. 1 , or it may be used in other systems and methods. 
     In the  FIGS. 2 &amp; 3  example, the variable flow restrictor  46  is contained within an outer housing assembly  48 . As depicted in  FIGS. 2 &amp; 3 , a closure device  50 , a retaining device  52  and a frusto-conical wedge  54  are integrally formed and reciprocably disposed in an inner housing  56 . The inner housing  56  comprises a biasing device  58  and a ported structure  60 . 
     The closure device  50  has two positions in which it either blocks (see  FIG. 2 ) or permits (see  FIG. 3 ) flow  40  through a flow passage  62  formed through the structure  60 . In both positions of the closure device  50 , flow  40  is permitted longitudinally through the flow passage  32  (which extends longitudinally through the flow restriction tool  22 ). 
     In the position depicted in  FIG. 2 , the flow  40  cannot pass through a flow area of the passage  62 , and so a total area available for flow longitudinally through the tool  22  is reduced, as compared to the position depicted in  FIG. 3 . Thus, a restriction to flow is increased in  FIG. 2 , as compared to that in  FIG. 3 . 
     In the  FIG. 2  position, only a flow area f 1  is available for the flow  40 . In the  FIG. 3  position, an additional flow area f 2  is available for the flow  40 . Thus, in  FIG. 2  a total available flow area is f 1 , but in  FIG. 3  the total available flow area is f 1 +f 2 . 
     To displace the closure device  50  from the  FIG. 2  position to the  FIG. 3  position, a flow rate of the flow  40  is increased. Since the flow area f 1  through the closure device  50  is in this example a least available flow area of the passage  32 , a pressure differential results across the closure device. 
     This pressure differential biases the closure device  50  downward (as viewed in  FIG. 2 ) toward the  FIG. 3  position. The retaining device  52  retains the closure device  50  in its  FIG. 2  position, until the flow rate is greater than a predetermined level. 
     In the  FIGS. 2 &amp; 3  example, the retaining device  52  comprises multiple resilient collets  64 . Each of the collets  64  has a radially enlarged projection  66  that releasably engages an annular recess  68  formed in the inner housing  56 . 
     The projections  66  and the recess  68  are configured so that, as a biasing force acting on the closure device  50  due to the flow  40  through the flow area f 1  increases, the collets  64  are increasingly deformed radially inward. When the predetermined flow rate is exceeded, the collets  64  are sufficiently deformed, so that the projections  66  are no longer engaged with the recess  68 , and the closure device  50  can be displaced to the  FIG. 3  position by the biasing force. 
     Although the retaining device  52  is described herein and illustrated in the drawings as comprising the resilient collets  64  and the recess  68 , it will be appreciated that other types of retaining devices could be used instead. For example, a snap ring could be used. Thus, the scope of this disclosure is not limited to use of any particular type of retaining device. 
     In the  FIG. 3  position, the flow  40  is permitted to pass through openings  70  formed through a generally tubular sleeve  72  of the closure device  50 . The flow  40  can then pass through the passage  62  to the passage  32  below the flow restriction tool  22 . 
     Note that displacement of the wedge  54  with the closure device  50  from the  FIG. 2  position to the  FIG. 3  position causes multiple resilient collets  74  formed on the inner housing  56  to be deformed radially outward. Because the deformed collets  74  are outwardly supported by a conical outer surface  54   a  of the wedge  54  in the  FIG. 3  position, a biasing force exerted by the collets on the wedge longitudinally biases the wedge and the closure device  50  toward the  FIG. 2  position. 
     Thus, the longitudinal biasing force exerted on the closure device  50  due to the flow  40  through the flow area f 1  must be greater than the longitudinal biasing force exerted on the wedge  54  by the collets  74 , in order to maintain the closure device in the  FIG. 3  position. If the flow rate decreases below a predetermined level, the longitudinal biasing force exerted on the wedge  54  by the collets  74  will exceed the biasing force exerted on the closure device  50  due to the flow  40  through the flow area f 1 , and the closure device will displace back to the  FIG. 2  position. 
     In this manner, the flow restriction tool  22  can be “reset,” so that the total flow area through the tool is again only f 1 , and restriction to the flow  40  is increased. If it is desired to then decrease the restriction to the flow  40 , the flow rate can again be increased, in order to displace the closure device  50  to the  FIG. 3  position. Thus, the restriction to flow  40  can be conveniently and repeatedly increased and decreased by respectively decreasing and increasing the flow rate. 
     Although the biasing device  58  is described herein and depicted in the drawings as comprising the resilient collets  74  acting on the conical outer surface  54   a  of the wedge  54 , it will be appreciated that other types of biasing devices could be used. For example, a compression spring or an extension spring could be used. Thus, the scope of this disclosure is not limited to use of any particular type of biasing device. 
     Although the flow restriction tool  22  is described above as being used in an operation wherein the window joint  20  is rotationally oriented in the wellbore  14 , the scope of this disclosure is not limited to use of the flow restriction tool for any particular purpose. Other types of equipment (such as, whipstocks, etc.) could be oriented in a well using the flow restriction tool  22 , and it is not necessary for the flow restriction tool to be used in a rotational orienting operation at all. 
     It may now be fully appreciated that the above disclosure provides significant advancements to the art of regulating flow through a well tool string. In examples described above, a flow area through the flow restriction device  22  can be increased and decreased repeatedly by respectively increasing and decreasing a flow rate of the flow  40 . 
     In one aspect, a flow restriction tool  22  for use in a subterranean well is provided to the art by the above disclosure. In one example, the flow restriction tool  22  can comprise: a closure device  50  reciprocably displaceable between first and second positions in which flow  40  is permitted longitudinally through the flow restriction tool  22 . In the first position (see  FIG. 2 ) a first flow passage  32  is open to the flow  40  and the closure device  50  blocks the flow  40  through a second flow passage  62 . In the second position (see  FIG. 3 ) the first and second flow passages  32 ,  62  are open to the flow  40 . A biasing device  58  displaces the closure device  50  to the first position in response to a flow rate of the flow  40  being reduced to less than a first predetermined level. 
     The flow restriction tool  22  can also comprise a retaining device  52  that releasably retains the closure device  50  in the first position. The retaining device  52  may permit displacement of the closure device  50  from the first position to the second position in response to the flow rate being increased to greater than a second predetermined level. 
     The retaining device  52  may comprise at least one resilient collet  64 . The biasing device  58  may comprise at least one resilient collet  74 . 
     The closure device  50  can comprise a sleeve  72 , and in the second position the flow  40  may pass through a wall of the sleeve  72  (e.g., via the openings  70 ). 
     The biasing device  58  can radially outwardly surround a generally conically shaped outer surface  54   a  connected to the closure device  50 . 
     A well tool string  12  is also provided to the art by the above disclosure. In one example, the well tool string  12  can comprise: an orientation tool  18  that selectively permits and prevents fluid communication between an interior and an exterior of the tool string  12  and thereby transmits orientation data via multiple pressure pulses  30  in a flow passage  32  extending longitudinally through the well tool string  12 ; and a flow restriction tool  22  that permits flow  40  through a first flow area f 1  when a flow rate of the flow  40  is less than a first predetermined level, and permits the flow  40  through a second flow area f 1 +f 2  greater than the first flow area f 1  when the flow rate is greater than a second predetermined level. 
     The flow restriction tool  22  may permit flow through the first flow area f 1 , but not the second flow area f 1 +f 2 , when the flow rate is reduced from above to below the first predetermined level. 
     A method of orienting a well tool string  12  in a well is also described above. In one example, the method can comprise: flowing fluid through the well tool string  12  at a flow rate, a flow restriction tool  22  restricting flow through the well tool string  12  and thereby producing a pressure differential from an interior to an exterior of the tool string  12 , an orientation tool  18  selectively permitting and preventing fluid communication through a wall  28  of the well tool string  12  and thereby encoding orientation data; increasing the flow rate and thereby increasing a flow area through the flow restriction tool  22 ; and then decreasing the flow rate and thereby decreasing the flow area through the flow restriction tool  22  while still permitting flow through the flow restriction tool  22 . 
     The step of increasing the flow area can include displacing a closure device  50  against a biasing force exerted by a biasing device  58 . The step of displacing the closure device  50  can include deforming at least one collet  74  of the biasing device  58 . 
     The step of decreasing the flow area can include retaining a closure device  50  in a position in which a flow passage  62  is blocked by the closure device  50 . The step of retaining the closure device  50  can include engaging at least one resilient collet  64  of a retaining device  52 . 
     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. For example, structures disclosed as being separately formed can, in other examples, be integrally formed and vice versa. 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.