Patent Publication Number: US-2022220842-A1

Title: Indication of compression loading in downhole tool strings

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the filing date of U.S. provisional application No. 63/135,454 filed on 8 Jan. 2021. The entire disclosure of the 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 examples described below, more particularly provides for indication of compression in downhole tool strings. 
     In various different types of well operations, it can be useful to know whether sufficient compression loading is being applied to a tool string downhole. For example, in drilling operations, such compression loading relates to “weight on bit,” which is needed for cutting into the earth by a drill bit. 
     It will, therefore, be readily appreciated that improvements are continually needed in the art of indicating compression loading in downhole tool strings. Such improvements may be useful in a variety of different well operations, such as drilling, completion, stimulation, injection and other types of operations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a representative partially cross-sectional view of an example of a well system and associated method which can embody principles of this disclosure. 
         FIG. 2  is a representative cross-sectional view of an example of a compression indication tool that may be used in the  FIG. 1  system and method, the compression indication tool being depicted in a closed run-in configuration. 
         FIG. 3  is a representative cross-sectional perspective view of a valve and flexible member section of the  FIG. 2  compression indication tool depicted in an open actuated configuration. 
         FIG. 4  is a representative cross-sectional view of the  FIG. 2  compression indication tool depicted in an open actuated configuration. 
         FIG. 5  is a representative cross-sectional view of another example of the compression indication tool depicted in a closed run-in configuration. 
         FIG. 6  is a representative cross-sectional view of the  FIG. 5  compression indication tool depicted in a partially actuated configuration. 
         FIG. 7  is a representative cross-sectional view of the  FIG. 5  compression indication tool depicted in a fully open actuated configuration. 
     
    
    
     DETAILED DESCRIPTION 
     Representatively illustrated in the accompanying drawings are examples of downhole tool string compression loading indication systems, methods and apparatus which can embody principles of this disclosure. However, it should be clearly understood that the particularly described systems, methods and apparatus are merely examples 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 systems, methods and apparatus described herein and/or depicted in the drawings. 
     Referring to  FIG. 1 , an example of a system  10  for use with a subterranean well is representatively illustrated. In this example, a drill string  12  is positioned in a wellbore  14 , in order to elongate the wellbore by drilling further into the earth. 
     A tool string  16  of the type known to those skilled in the art as a bottom hole assembly (BHA) is connected at a distal end of, and forms a lower section of, the drill string  12 . In this example, the tool string  16  includes a drill bit  18 , a drill motor  20 , various logging and communication tools  22 , and a compression indication tool  24 . However, the scope of this disclosure is not limited to any particular tools or combination of tools in a BHA. 
     The tool string  16  is positioned in a generally horizontal section of the wellbore  14 . In such situations, it can be difficult to determine whether or to what degree compression loading is being applied to the tool string  16  (for example, due to friction between the drill string  12  and the wellbore  14 ). It will be appreciated by those skilled in the art that, especially in drilling operations, it is very important to know the compression loading in a BHA and corresponding compressive force applied to the drill bit, at least because this affects a rate of penetration of the drill bit into the earth and can affect other functions/capabilities (such as, steering of the drill bit, bit wear, etc.). 
     Note that, although  FIG. 1  depicts a drilling operation, the scope of this disclosure is not limited to drilling operations in horizontal wellbore sections or use of the compression indication tool  24  in any particular type of tool string. The compression indication tool  24  could, for example, be used in completion, stimulation, workover, or other types of operations in vertical, inclined or any other orientation wellbores. 
     In the  FIG. 1  example, the compression indication tool  24  includes a port  26  that selectively provides fluid communication between an internal flow passage  32  extending longitudinally through the tool string  16  and an annulus  28  formed between the tool string and the wellbore  14 . During normal drilling operations, fluid  30  is circulated through the drill string  12 . The fluid  30  flows through the flow passage  32  in the tool string  16  and exits the drill bit  18  into the annulus  28  for return to the surface. There typically is a significant pressure drop from the flow passage  32  to the annulus  28 , due in part to flow restrictions in the tool string  16  (particularly in the communication tools  22 , the drill motor  20  and nozzles in the drill bit  18 ). 
     However, in the  FIG. 1  system  10 , the compression indication tool  24  is actuated to permit fluid communication between the flow passage  32  and the annulus  28  when a predetermined compressive load is applied to the tool string  16 . This fluid communication reduces the pressure drop from the flow passage  32  to the annulus  28 . Thus, an operator at the surface can detect a reduction in pressure applied to the drill string  12  when the predetermined compressive load is applied to the tool string  16 . 
     In some examples, the compression indication tool  24  can be used to determine when the tool string  16  has been “set down” at a distal end of the wellbore  14 , so that drilling into the earth can commence. In other examples, the compression indication tool  24  can be used to determine whether a tool string  16  has engaged a nipple, lock coupling, shifting profile, shoulder or other profile in a well. The scope of this disclosure is not limited to any particular purpose for indicating compression loading in a tubular string (such as, the drill string  12  or a completion, workover, stimulation, injection or other type of tubular string) in a well. 
     Referring now to  FIG. 2 , a more detailed view of one example of the compression indication tool  24  is representatively illustrated. In this view, the compression indication tool  24  is in a run-in configuration in which the predetermined compressive load is not applied to the tool. The  FIG. 2  compression indication tool  24  may be used with the system  10  and method of  FIG. 1 , or it may be used with other systems and methods. 
     The flow passage  32  extends longitudinally through the tool  24 . A poppet valve  34  initially prevents fluid communication between the flow passage  32  and an exterior of the tool  24  (corresponding to the annulus  28  in the  FIG. 1  example). However, when the poppet valve  34  is opened, fluid  30  can flow from the flow passage  32  to the exterior of the tool  24  via the port  26 . 
     The poppet valve  34  in this example includes an annular closure member  38  that is initially biased toward a closed position by a compression spring or other biasing device  36  (such as, a compressed gas chamber, an elastomer, a compressible liquid, etc.). When the tool  24  is in tension or the predetermined compressive load is not applied to the tool, the poppet valve closure member  38  is sealingly engaged with an annular valve seat  40 . 
     An inner mandrel  42  extends longitudinally through the poppet valve closure member  38  and valve seat  40 . The inner mandrel  42  extends longitudinally from an upper connector  44  having an axially splined connection  46  with an outer housing assembly  48  of the tool  24 . A tapered collet prop  50  is connected at an opposite end of the inner mandrel  42 . 
     The splined connection  46  allows torque to be transmitted between the upper connector  44  and the outer housing assembly  48 , and permits axial displacement of the upper connector relative to the outer housing assembly. Displacement of the upper connector  44  to the right (as viewed in  FIG. 2 ) relative to the outer housing assembly  48  is resisted by abutting engagement between the tapered collet prop  50  and upper ends of multiple flexible collets  52 . 
     However, when a sufficient compressive load is applied across the tool  24 , the collets  52  will flex radially outward (due to the tapered surfaces  54  formed on the collet prop  50  and the upper ends of the collets). This outward flexing of the collets  52  will allow the collet prop  50 , the inner mandrel  42  and the upper connector  44  to displace somewhat to the right as viewed in  FIG. 2 . 
     This rightward displacement is limited by a longitudinal spacing S 1  between shoulders formed on the inner mandrel  42  and in the outer housing assembly  48 . A smaller longitudinal spacing S 2  exists between an upper end of the poppet valve closure member  38  and an annular shoulder formed on the inner mandrel  42 . Thus, the annular shoulder on the inner mandrel  42  will engage and displace the poppet valve closure member  38  rightward before the inner mandrel shoulders up against the interior shoulder in the outer housing assembly  48 . This will open the poppet valve  34  and permit fluid communication between the flow passage  32  and the exterior of the tool  24 . 
     A more detailed view of an example of the poppet valve  34 , collet prop  50  and collets  52  is depicted in  FIG. 3 . Note that the predetermined compressive load at which the poppet valve  34  opens can be varied in a variety of different ways. For example, a stiffness of the collets  52  can be varied by varying a strength of a material of which the collets are made, or by varying a size (e.g., width, thickness, length, etc.) or other property (e.g., second moment of area, etc.) of the collets. As another alternative, the tapered surfaces  54  formed on the collets  52  and the collet prop  50  can be varied. 
     Referring additionally now to  FIG. 4 , the compression indication tool  24  is depicted after the predetermined compressive load has been applied to the tool. Note that the poppet valve  34  is now open (the closure member  38  no longer sealing against the valve seat  40 ), so that fluid communication is now permitted between the flow passage  32  and the exterior of the tool  24  via the port  26 . 
     The collets  52  have been deflected radially outward by the collet prop  50 . This allows the inner mandrel  42  to displace to the right (as viewed in  FIG. 4 ) and thereby open the poppet valve  34 . Thus, the fluid  30  can flow between the closure member  38  and the valve seat  40 . 
     The tool  24  can be returned to the closed configuration by reducing the compressive load applied to the tool (or by applying tension to the tool), so that the poppet valve closure member  38  is displaced back to its closed position in sealing engagement with the valve seat  40 . 
     As mentioned above, the predetermined compressive load at which the poppet valve  34  opens can be varied by varying a characteristic of the collets  52 . In the  FIGS. 2-4  example, an effective flexible length of the collets  52  can be varied by displacing a ring  56  relative to the collets. This allows the predetermined compressive load to be conveniently adjusted, for example, at a well site when actual well conditions are known or have changed, without requiring disassembly of the tool  24 . 
     The ring  56  can be displaced relative to the collets  52  by turning an adjustment mechanism  58  (including left-hand and right-hand threaded members  60 ,  62 ), so that the ring is displaced longitudinally along an exterior of the collets. As depicted in  FIG. 4 , an effective bending length of the collets  52  is decreased when the ring  56  is displaced to the left, and the effective bending length of the collets is increased when the ring is displaced to the right. A longer effective bending length provides increased flexibility and reduced stiffness (and, thus, reduced predetermined compressive load to open the poppet valve  34 ), and a shorter effective bending length provides increased stiffness and reduced flexibility (and, thus, increased predetermined compressive load to open the poppet valve). 
     A cross-sectional view of another example of the compression indication tool  24  is representatively illustrated in  FIGS. 5-7 . This example is similar in some respects to the  FIGS. 2-4  example. However, instead of forcing the collet prop  50  into the collets  52  in order to open the poppet valve  34  as in the  FIGS. 2-4  example, in the  FIGS. 5-7  example springs (or another biasing device  64 ) are longitudinally compressed in order to align an opening  66  in the inner mandrel  42  with the port  26 , thereby permitting fluid communication between the flow passage  32  and the exterior of the tool  24 . 
     The combination of the inner mandrel  42  and the opening  66 , and the outer housing assembly  48  and the port  26 , is similar to a sliding sleeve valve. In the  FIG. 5  run-in configuration, the inner mandrel  42  is in a closed position with respect to the outer housing assembly  48  (the sliding sleeve valve is closed). In  FIG. 6 , a longitudinal compressive load is being applied to the compression indication tool  24 , but the valve  34  is not yet fully opened. In the  FIG. 7  actuated configuration, the inner mandrel  42  is in an open position with respect to the outer housing assembly  48  (the sliding sleeve valve  34  is open). 
     When a predetermined compressive load is applied to the tool  24 , the springs or other biasing device  64  will longitudinally compress and the inner mandrel  42  will displace from the closed position to the open position. The level of the predetermined compressive load can be adjusted by varying the spring rate of the springs, by varying a number of the springs (in this example Bellville washer springs), by varying a compressive preload in the springs, etc. 
     A compressive preload in the springs or other biasing device  64  can be conveniently adjusted (for example, at a well site when actual well conditions are known or have changed) by turning an externally threaded adjustment sleeve  68  in a lower connector  70  of the tool  24 . An externally threaded lock sleeve  72  is used to bind against the adjustment sleeve  68  when it is positioned as desired. The adjustment sleeve  68  and the lock sleeve  72  can be rotated using tools (not shown) inserted into an end of the lower connector  70 , without requiring disassembly of any portion of the tool  24 . 
     Note that an annular chamber  74  is formed radially between two seal bores  76 ,  78 . The annular chamber  74  is exposed to fluid pressure on the exterior of the tool (the annulus  28  in the  FIG. 1  example). An annular chamber  82  between the seal bore  76  and a seal diameter or seal bore  80  is exposed to fluid pressure in the flow passage  32 . 
     When fluid  30  is circulating through the tool string  16  (in the  FIG. 1  example), and the compression indication tool  24  is in its  FIG. 5  closed configuration (the predetermined compressive load is not applied), fluid pressure in the flow passage  32  will be greater than fluid pressure on the exterior of the tool. The seal bores  76 ,  78 ,  80  depicted in  FIG. 5  are configured so that the greater pressure in the flow passage  32  acting on the differential areas results in a force acting to elongate the tool  24  (i.e., to prevent compression of the tool). 
     However, when the valve  34  is open (see  FIG. 7 ), the fluid pressures in the flow passage  32  and on the exterior of the tool  24  are equalized, or at least the pressure differential from the flow passage to the exterior of the tool is decreased. Thus, in the open configuration of  FIG. 7 , the force acting to elongate the tool  24  is decreased. This helps to maintain the tool  24  in the open configuration and prevent oscillation or “chatter” of the tool between the open and closed configurations, while the predetermined compressive load is applied to the tool. 
     The compression indication tool  24  can be returned to the closed configuration by reducing the compressive load applied to the tool (or by applying tension to the tool), so that the springs or other biasing device  64  can displace the inner mandrel  42  back to its closed position. The tool  24  can be actuated between its closed and open configurations multiple times while it is deployed into a wellbore. 
     It may now be fully appreciated that the above disclosure provides significant advancements to the art of controlling downhole operations. In examples described above, application of at least a predetermined compressive load to the tool string  16  is indicated by opening the valve  34  to permit fluid communication between the internal flow passage  32  and an annulus  28  surrounding a compression indication tool  24 . In one example the valve  34  comprises a poppet valve, and in another example the valve  34  comprises a sliding sleeve valve. 
     A compression indication tool  24  can be connected in a tubular string (such as the drill string  16 ), so that fluid communication is permitted between an interior and an exterior of the tubular string in response to a predetermined compressive load being applied to the tubular string at the compression indication tool. 
     A method described above can include applying a predetermined compressive load to a drill string  16 , observing a decrease in fluid pressure in the drill string (for example, at the surface), and then drilling ahead in response to observing the fluid pressure decrease. 
     A method of indicating compression loading in a tubular string  16  can include adjusting a characteristic (such as a strength of a material, a size (e.g., width, thickness, length, angle of a tapered surface, etc.) or other property (e.g., second moment of area, flexibility, stiffness, effective bending length, etc.)) of a flexible member (such as the collets  52 ) of a compression indication tool  24 , then deploying the tool into a well, and then applying a predetermined compressive load to the tool to indicate the compression loading to an operator. The predetermined compressive load is determined at least in part by the adjustment to the characteristic of the flexible member. 
     A compression loading indication system, method and apparatus are also described above, in which a hydraulic area (such as, the areas defined by the seal bores  76 ,  78 ,  80 ) in a compression indication tool  24  resists longitudinal compression of the tool. A pressure differential applied from the internal flow passage  32  to the annulus  28  or exterior of the tool  24  acts to maintain an elongated configuration of the tool. 
     The pressure differential is reduced when the tool  24  is longitudinally compressed. Fluid communication is permitted between the interior and the exterior of the tool  24  in response to the longitudinal compression of the tool. 
     A compression loading indication system, method and apparatus are described above, in which a predetermined compressive load required to actuate a compression indication tool  24  is adjustable without disassembling the compression indication tool. For example, the threaded members  60 ,  62  are externally accessible in the  FIGS. 2-4  compression indication tool  24  example, and the adjustment sleeve  68  and lock sleeve  72  are externally accessible in the  FIGS. 5-7  compression indication tool  24  example. 
     The predetermined compressive load may be adjustable by varying a stiffness of a flexible member (such as the collets  52 ). The predetermined compressive load may be adjustable by varying a preload in a spring or other biasing device  64 . The predetermined compressive load may be adjustable by insertion of a tool into an end of the compression indication tool  24  and rotating an adjustment member (such as the threaded members  60 ,  62  or the adjustment sleeve  68 ). 
     The above disclosure provides to the art a compression indication tool  24  for use in a subterranean well. In one example, the compression indication tool  24  comprises a flow passage  32  that extends longitudinally through the compression indication tool  24 , and a valve  34  that in a closed configuration prevents fluid communication through the valve  34  between the interior flow passage  32  and an exterior of the compression indication tool  24 , and in an open configuration permits fluid communication through the valve  34  between the interior flow passage  32  and the exterior of the compression indication tool  24 . The valve  34  is actuated from the closed configuration to the open configuration in response to application of a predetermined longitudinal compressive load to the compression indication tool  24 . 
     A longitudinal length of the compression indication tool  24  may be shortened in response to the application of the predetermined longitudinal compressive load. 
     The valve  34  may comprise a poppet valve. The poppet valve  34  may comprise an annular closure member  38  that sealingly engages an annular seat  40  in the closed configuration. The valve  34  may comprise a sliding sleeve valve. 
     The compression indication tool  24  may include a flexible member (such as the collets  52 ) that resists longitudinal compression of the compression indication tool  24 . The predetermined longitudinal compressive load may be variable in response to a variation in a characteristic of the flexible member  52 . 
     The characteristic may comprise a flexibility of the flexible member  52 . The flexibility of the flexible member  52  may be variable from the exterior of the compression indication tool  24 . The characteristic may comprise an angle of a tapered surface  54  on the flexible member  52 . 
     The compression indication tool  24  may comprise a biasing device  64  that resists longitudinal compression of the compression indication tool  24 . The predetermined longitudinal compressive load may be variable in response to a variation in at least one of a spring rate and a preload of the biasing device  64 . 
     Longitudinal compression of the compression indication tool  24  may be resisted in response to a pressure differential from the interior flow passage  32  to the exterior of the compression indication tool  24 . Multiple seal bores  76 ,  78 ,  80  of the compression indication tool  24  may be configured so that a pressure differential from the interior flow passage  32  to the exterior of the compression indication tool  24  acting on annular chambers  74 ,  82  between the seal bores  76 ,  78 ,  80  resists longitudinal compression of the compression indication tool  24 . 
     A method for use with a subterranean well is also provided to the art by the above disclosure. In one example, the method may comprise: connecting a compression indication tool  24  in a tool string  16 , the compression indication tool  24  comprising a valve  34  that prevents fluid communication through the valve  34  between an interior flow passage  32  and an exterior of the compression indication tool  24 ; deploying the tool string  16  into the well; and applying a predetermined longitudinal compressive load to the tool string  16 , thereby opening the valve  34  to permit fluid communication through the valve  34  between the interior flow passage  32  and the exterior of the compression indication tool  24 . 
     The applying step may comprise observing a decrease in fluid pressure applied to the tool string  16 . The applying step may comprise decreasing a pressure differential from the interior flow passage  32  to the exterior of the compression indication tool  24 . The method may comprise applying the pressure differential from the interior flow passage  32  to the exterior of the compression indication tool  24  prior to the step of applying the predetermined longitudinal compressive load. 
     The applying step may comprise deflecting a flexible member  52  of the compression indication tool  24 . The deflecting step may comprise radially outwardly deflecting the flexible member  52 . The method may include adjusting a characteristic of the flexible member  52 , thereby varying the predetermined longitudinal compressive load. 
     The applying step may comprise longitudinally compressing a biasing device  64  of the compression indication tool  24 . The method may comprise adjusting a preload of the biasing device  64 , thereby varying the predetermined longitudinal compressive load. 
     The applying step may comprise decreasing a longitudinal length of the compression indication tool  24 . 
     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,” “upward,” “downward,” 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.