Patent Publication Number: US-2018044999-A1

Title: Device and method for securing conduit interior wear sleeve

Description:
FIELD OF THE INVENTION 
     The present invention relates to protective techniques and methodologies for conduit interiors, and more specifically to the use of sleeves as wear members or electrical insulators. 
     BACKGROUND OF THE INVENTION 
     It is known in the art of conduit design to employ covers or coatings to protect the inner conduit surfaces from corrosion or undue wear, as abrasive liquid/solid mixtures are often transported in a pipeline or conduit. The covers may be manufactured separately and inserted into the conduit, or they may be in the form of a spray-coating or similar application technique. The cover or sleeve material is commonly in the form of a plastic or metal material, the specific material selected on the basis of the application and the type, volume and velocity of fluid flow through the conduit. 
     For example, U.S. Pat. No. 8,397,766 to Rosen teaches a pipe welding method wherein adjacent pipe sections are provided with a plastic lining. The plastic lining may be secured in place by means such as an adhesive coating. 
     The use of a plastic liner or sleeve is also known to have potential advantages in the field of downhole electromagnetic telemetry, as commonly-used gap subs employ some degree of electrical isolation for operation. As is taught in Patent Cooperation Treaty Application No. PCT/CA2013/050850 to Logan et al., an electrically insulative sleeve can be used with a gap sub. 
     However, it is known that sleeves can be dislodged by normal fluid flow through a conduit, particularly in the context of drilling fluids or other high-velocity applications, as the fluids can flow behind the leading or upstream edge of the sleeve and eventually collapse it inwardly. This can have significant negative consequences where, for example, the conduit houses a probe or other tool, which is often found in gap sub assemblies. 
     Some solutions have been proposed, such as using an adhesive to retain the sleeve against the conduit inner walls, but this makes it more difficult to remove the sleeve. In the situation where the sleeve is sacrificial and is intended to be replaced from time to time, having the sleeve glued in place renders such replacements difficult. Additional time and cost may be required to remove such adhered sleeves, with the potential for damaging the inner walls of the conduit. 
     What is needed, therefore, is a method for providing a sacrificial sleeve for the inner walls of a conduit or pipe, while securing at least the upstream end of the sleeve to prevent or reduce the risk of fluid getting behind the sleeve and causing deformation and a collapse. Preferably, such a method would not include the use of adhesives and would allow for easier replacement of worn sleeves. 
     SUMMARY OF THE INVENTION 
     The present invention therefore seeks to provide a retention device and method for securing at least an upstream or leading edge of a wear sleeve within a pipe or conduit interior. The present invention extends to conduits and gap subs comprising such a device. 
     According to a first broad aspect of the present invention, there is provided a conduit comprising:
         an internal conduit wall defining an inner passage through the conduit for receiving and transporting materials;   a wear member positioned within the inner passage and contacting the internal conduit wall; and   at least one retention member for securing an upstream end of the wear member against the internal conduit wall.       

     In some exemplary embodiments of the first aspect, the internal conduit wall is substantially cylindrical and the wear member is substantially cylindrical, the wear member forming a sleeve that covers at least a portion of the internal conduit wall. The wear member may be composed of a plastic material such as thermoplastics, thermoset polymers, elastomeric polymers or rubber, polyethylene terephthalate, polyether ether ketone or polyphenylene sulfide. Alternatively, the wear member may be composed of a metal material. 
     The conduit may comprise a gap sub assembly, and the wear member may preferably be composed of an electrically insulative material. 
     The at least one retention member preferably comprises a ring in engagement (which may, for example, be slip-fit or threaded engagement) with the internal conduit wall, the ring comprising a lip extending in a downhole direction, the lip configured to press a portion of the upstream end of the wear member outwardly against the internal conduit wall. The ring may also comprise a shoulder for abutting engagement with the upstream end of the wear member, and the ring may be in sealing engagement with the internal conduit wall by means of at least one  0 -ring. The ring may be composed of a metal selected from the group consisting of beryllium copper and stainless steel, and it may be held in position by abutting against a shoulder on the internal conduit wall. 
     Alternatively, the at least one retention member may comprise a probe retention member in slip-fit engagement with the internal conduit wall, the probe retention member comprising a lip extending in a downhole direction, the lip configured to press a portion of the upstream end of the wear member outwardly against the internal conduit wall, the probe retention member configured to retain a probe within the inner passage. The probe retention member may be composed of a metal selected from the group consisting of beryllium copper and stainless steel. 
     The conduit may also comprise at least one downhole retention member for securing a downstream end of the wear member against the internal conduit wall. The at least one downhole retention member may be mounted on the internal conduit wall, or it may be of unitary construction with the internal conduit wall. 
     According to a second broad aspect of the present invention, there is provided a retention member for securing a wear member inside a conduit, the conduit having an internal wall, the wear member sized and configured for slip-fit engagement with the internal wall, the retention member comprising at least one projection extending adjacent the wear member to hold at least a portion of the wear member against the internal wall. 
     In some exemplary embodiments of the second aspect, the at least one projection comprises a circumferential lip extending generally parallel to the internal wall. The retention member may further comprise a shoulder for abutting engagement with the at least a portion of the wear member. In some embodiments the retention member may comprise at least one  0 -ring for sealing engagement of the retention member against the internal wall. The retention member may also comprise an internal extension for retaining a probe within the conduit. The retention member is preferably composed of a material selected from the group consisting of beryllium copper and stainless steel. 
     According to a third broad aspect of the present invention, there is provided a wear assembly for use with an internal wall of a conduit, the wear assembly comprising:
         a sacrificial sleeve sized and configured for slip-fit engagement with the internal wall; and   a retention member;   the retention member comprising at least one protuberance for securing an upstream end of the sleeve against the internal wall.       

     In some exemplary embodiments of the third aspect, the sleeve is composed of a plastic material, the plastic material deformable when fluid flowing through the conduit flows under the upstream end of the sleeve, the protuberance sized and configured to retain the upstream end of the sleeve against the internal wall to reduce the flow of the fluid under the upstream end of the sleeve. The retention member may further comprise at least one O-ring for sealing engagement with the internal wall, and the retention member is preferably composed of a material selected from the group consisting of beryllium copper and stainless steel. 
     The conduit may comprise a gap sub assembly, with the sleeve composed of an electrically insulative material. The electrically insulative material is preferably selected from the group consisting of polyethylene terephthalate, polyphenylene sulfide and polyether ether ketone. 
     The at least one protuberance preferably comprises a circumferential lip for positioning adjacent the sleeve, and the retention member may further comprise a shoulder for abutting engagement with the upstream end of the sleeve. 
     A wear assembly according to exemplary embodiments further preferably comprises a downstream retention member for securing a downstream end of the sleeve against the internal wall, and the retention member may further comprise an internal extension for retaining a probe within the conduit. 
     According to a fourth broad aspect of the present invention, there is provided a gap sub for insertion in a drill string, the gap sub comprising:
         a male member;   a female member, the male and female members configured for threadable connection; an electrically insulative gap member configured for positioning between the male and female members;   the male and female members and the gap member when connected forming an internal wall;   a sacrificial sleeve for slip-fit engagement with the internal wall; and   a retention member for slip-fit engagement with the internal wall, the retention member sized and configured to secure an upstream end of the sleeve against the internal wall and reduce introduction under the sleeve of fluid flowing through the gap sub.       

     In some exemplary embodiments of the fourth aspect, the retention member comprises at least one protuberance for bearing against the upstream end of the sleeve to press the upstream end against the internal wall, and the protuberance preferably comprises a circumferential lip. The retention member may comprise an internally-disposed extension for receiving a probe within the gap sub. The sleeve is preferably composed of an electrically insulative material. 
     According to a fifth broad aspect of the present invention, there is provided a method of reducing wear of an internal wall of a conduit, the method comprising the steps of:
         a. providing a wear member sized and configured for slip-fit engagement with the internal wall;   b inserting the wear member into the conduit so as to engage the internal wall; and   c. engaging retention means to press an upstream end of the wear member against the internal wall.       

     In some exemplary embodiments of the fifth aspect, the wear member is a sacrificial plastic sleeve, while in other embodiments it is composed of a metal material. The wear member is sized to cover at least a portion of the internal wall. In some embodiments it is advantageous to have the wear member composed of an electrically isolative material, for example where the conduit is a gap sub. 
     The retention means preferably comprise a retention member sized and configured for slip-fit engagement with the internal wall, and the engaging of the retention means comprises inserting the retention member into the conduit and pressing the retention member against the wear member. Such a retention member preferably comprises at least one downwardly extending protuberance for pressing the upstream end of the wear member against the internal wall, and the at least one downwardly extending protuberance most preferably comprises a circumferential lip. The retention member may also comprise a circumferential shoulder for abutting engagement with the upstream end of the wear member, for securing the wear member in place simultaneously with the pressing of the wear member against the internal wall. In addition, the method may include the step of engaging a downstream retention means to press a downstream end of the wear member against the internal wall. 
     According to a sixth broad aspect of the present invention, there is provided a method of securing a wear member within an inner passage of a conduit, the inner passage defined by an internal wall of the conduit, the method comprising the steps of:
         a. providing the wear member, the wear member sized and configured for slip-fit engagement with the internal wall;   b. inserting the wear member into the inner passage so as to engage the internal wall; and   c. engaging retention means to press an upstream end of the wear member against the internal wall.       

     In some exemplary embodiments of the sixth aspect, the wear member is a sacrificial plastic sleeve, but in some other embodiments it may be composed of a metal material. In embodiments where the conduit is a gap sub, the wear member is preferably composed of an electrically isolative material. The wear member is preferably sized to cover at least a portion of the internal wall. 
     The retention means may comprise a retention member sized and configured for engagement (which may, for example, be slip-fit or threaded engagement) with the internal wall, and the engaging of the retention means comprises inserting the retention member into the inner passage and pressing the retention member against the wear member. Such a retention member may comprise at least one downwardly extending protuberance for pressing the upstream end of the wear member against the internal wall, and the at least one downwardly extending protuberance preferably comprises a circumferential lip. The retention member may also comprise a circumferential shoulder for abutting engagement with the upstream end of the wear member, for securing the wear member in place simultaneously with the pressing of the wear member against the internal wall. The method may further comprise engaging a downstream retention means to press a downstream end of the wear member against the internal wall. 
     A detailed description of exemplary embodiments of the present invention is given in the following. It is to be understood, however, that the invention is not to be construed as being limited to these embodiments. The exemplary embodiments are directed to particular applications of the present invention, while it will be clear to those skilled in the art that the present invention has applicability beyond the exemplary embodiments set forth herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings, which illustrate exemplary embodiments of the present invention: 
         FIG. 1  is a sectional view of a gap sub with retaining means according to an exemplary embodiment of the present invention, with two detailed views of the downstream and upstream ends of the wear sleeve; 
         FIG. 2  is a perspective, plan and sectional view of a retaining ring in accordance with an exemplary embodiment of the present invention; 
         FIG. 3  is a cut-away perspective, sectional and detailed view of an assembly in accordance with an exemplary embodiment of the present invention, with a landing spider and retaining ring in position against a sleeve; 
         FIG. 4  is a perspective, plan and sectional view of a landing spider in accordance with an exemplary embodiment of the present invention, in which the landing spider comprises the sleeve retention means; and 
         FIG. 5  is a cut-away perspective, sectional and detailed view of the landing spider of  FIG. 4  retaining a sleeve in position. 
     
    
    
     Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. The following description of examples of the technology is not intended to be exhaustive or to limit the invention to the precise forms of any exemplary embodiment. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense. For example, although the present invention is illustrated as being applied to a gap sub for use in electromagnetic telemetry operations, the present invention may be applied to any appropriate or suitable protective wear and/or electrical isolation member used with pipes or conduits. 
     Turning now to  FIG. 1 , a gap sub  10  is illustrated. The gap sub  10  comprises a male member  12  and a female member  14  separated by a gap member  46 , in a manner known to those of skill in the art. The male member  12  and female member  14  are each provided with a bore from one end to the other, to allow for passage of drilling fluid therethrough in operation, forming an inner passage  16 . The male member  12  is provided with an internal wall  18  that defines the inner passage  16  in that portion of the gap sub  10 . 
     In the embodiment illustrated in  FIG. 1 , the internal wall  18  is overlain by a sleeve  20 , which in this embodiment is composed of glass filled polyphenylene sulfide, a thermoplastic polymer resin. In the case of a gap sub, such a material may provide suitable wear prevention to the sleeve  20  while providing a desirable electrical isolation function. Those skilled in the art would be able to readily identify other materials that would be appropriate in a given context or application. The sleeve  20  as illustrated is a one-piece cylindrical sleeve that extends substantially the length of the male member  12  interior, between an upstream end  22  and a downstream end  24 . It will be obvious to those skilled in the art that the sleeve  20  need not be a one-piece construction in a given application. 
     A retaining ring  26  is shown in  FIG. 1 , most particularly in the detailed view of the upstream end  22  of the sleeve  20 . The retaining ring  26  is illustrated as a  2 -piece unit, but it will be clear to those skilled in the art that the retaining ring could alternatively be formed as a 1-piece unit. The retaining ring  26  is in slip-fit engagement with the internal wall  18  of the male member  12 , and an  0 -ring  30  is in place to promote a sealing engagement. The retaining ring  26  as illustrated is a ring-shaped member that is in circumferential engagement with the internal wall  18 . The retaining ring  26  comprises a lip  28  that is sized and positioned to receive the upstream end  22  of the sleeve  20  and hold it firmly against the internal wall  18 . The lip  28  itself extends around the entire circumference of the inner passage  16 , thus retaining the upstream end  22  along its full extent. Additional O-rings (not shown) may be positioned beneath the upstream and downstream ends  22 ,  24  of the sleeve  20  to aid in sealing with the internal wall  18 . 
     The retaining ring  26  further comprises a beveled face  32  to promote flow through the inner passage  16 . In addition, the retaining ring  26  comprises a shoulder  34  against which the upstream end  22  of the sleeve  20  abuts, while the downstream end  24  of the sleeve  20  abuts a shoulder  36  on the male member  12 , thus holding the sleeve  20  firmly in position when the retaining ring  26  has been inserted into the inner passage  16 . 
     The exemplary embodiment of  FIG. 1  includes retention means for the downstream end  24  of the sleeve  20 , as well. As can best be seen in the detail view of the downstream end  24 , the male member  12  is provided with a downstream lip  48  for securing the downstream end  24  of the sleeve  20 , such that both ends  22 ,  24  of the sleeve  20  are pressed outwardly against the internal wall  18 . While this exemplary embodiment shows the lip  48  and the shoulder  36  on a separate component part of the male member  12 , the separate component part abutting an internal shoulder of the male member  12 , it will be clear to those skilled in the art that the lip  48  and the shoulder  36  could be of unitary construction with the male member  12  in an alternative embodiment. 
     In the exemplary embodiment, the sleeve  20  is shown as secured by means of a slip-fit engagement with the upstream and downstream lips  28 ,  48  and abutting against the upstream and downstream shoulders  34 ,  36 . However, it is within the scope of the present invention to have other mechanisms for pressing the upstream and downstream ends  22 ,  24  against the internal wall  18 , such as for example a biasing mechanism. Those skilled in the art would be able to readily determine functionally equivalent mechanisms and techniques, all of which are intended to fall within the scope of the present invention as defined in the claims. 
     Turning now to  FIG. 2 , a slightly modified retaining ring  50  is illustrated. The retaining ring  50  comprises a circumferential lip  52  and a shoulder  54 , which function in a similar manner to the above description, but in this case there is no O-ring or other sealing feature on the side of the retaining ring  50 , unlike the embodiment of  FIG. 1 . 
       FIG. 3  illustrates a further exemplary embodiment of the present invention. In this embodiment, a landing spider  38  is inserted on top of the retaining ring  50  and a castle nut (not shown) further secures the landing spider  38  and the retaining ring  50  in place. The landing spider  38  is used to hold an electronics package, such as for example a probe for use in electromagnetic telemetry. The landing spider  38  comprises a peripheral ring  40  for slip-fit engagement with the internal wall  18  of the gap sub  10 , a plurality of arms  42  extending inwardly from the peripheral ring  40 , and a central mating hub  44  connected to the arms  42  and configured for retention of a given electronics package. 
       FIGS. 4 and 5  illustrate a further exemplary embodiment. In this embodiment, the retaining ring has been replaced by a modified landing spider  56  which combines the sleeve-securing and probe-holding functionalities in one device. The landing spider  56  comprises a peripheral ring  58 , arms  60  and a central mating hub  62 , with functionality as described above, but it also comprises a circumferential lip  64  and shoulder  66 . The circumferential lip  64  and shoulder  66  function is a similar way to the above description regarding the embodiment of  FIG. 1 , working together to secure the upstream end  22  of the sleeve  20  against the internal wall  18  of the gap sub  10 . 
     As will be clear from the above, those skilled in the art would be readily able to determine obvious physical variants capable of providing the retaining ring functionality, and all such variants and functional equivalents are intended to fall within the scope of the present invention. 
     The present invention also extends to methods or reducing conduit wall wear and securing protective wear members. 
     In one exemplary embodiment of a method according to the present invention, the method is for reducing wear of an internal wall of a conduit. Reference will be made to the elements shown in  FIG. 1  for ease of description. A sleeve  20  is manufactured to a suitable size and configuration for slip-fit engagement with the internal wall  18 . The sleeve  20  is inserted into the inner passage  16  of the female member  14 , abutting against the downstream shoulder  36  of the separate component part of the male member  12  and pressed against the internal wall  18  by means of the downstream lip  48 . The retaining ring  26  is then inserted through the inner passage  16  of the female member  14  until it meets the sleeve  20 . The retaining ring  26  is pressed downwardly against the upstream end  22  of the sleeve  20  until the upstream end  22  is seated against the upstream shoulder  34 , and the upstream end  22  will thus be pressed against the internal wall  18  by the lip  28 , as described above. With the sleeve  20  thus positioned and retained against the internal wall  18 , this exemplary embodiment may help to reduce wear of the internal wall  18 . 
     As indicated above, this exemplary method may further include inserting a landing spider or similar internal probe mechanism. Alternatively, as set out above, the landing spider itself could comprise the sleeve retention features of the retaining ring  26 . 
     In another exemplary embodiment of a method according to the present invention, the method is for securing a wear member within an inner passage of a conduit, the inner passage defined by an internal wall of the conduit. Reference will again be made to the elements shown in  FIG. 1  for ease of description. A sleeve  20  is manufactured to a suitable size and configuration for slip-fit engagement with the internal wall  18 . The sleeve  20  is inserted into the inner passage  16  of the female member  14 , abutting against the downstream shoulder  36  and pressed against the internal wall  18  by means of the downstream lip  48 . The retaining ring  26  is then inserted through the inner passage  16  of the female member  14  until it meets the sleeve  20 . The retaining ring  26  is pressed downwardly against the upstream end  22  of the sleeve  20  until the upstream end  22  is seated against the upstream shoulder  34 , and the upstream end  22  will thus be pressed against the internal wall  18  by the lip  28 , as described above. As indicated above, this exemplary method may further include inserting a landing spider or similar internal probe mechanism. Alternatively, as set out above, the landing spider itself could comprise the sleeve retention features of the retaining ring  26 . Thus, the sleeve  20  is secured in place in a novel manner and without the use of adhesives. 
     As will be clear to those of skill in the art, the present invention allows for a wear member application that can easily be replaced. When it is determined that the time has come for the sleeve  20  to be replaced, the section of conduit can be taken out of operation. The retaining ring  26  can be pulled away from the upstream end  22  of the sleeve  20 , thus freeing the upstream end  22 . The sleeve  20  can then be pulled away from the downstream shoulder  36  and disengaged from the downstream lip  48 , and then withdrawn from the inner passage  16 . A replacement sleeve can then be inserted and retention ring  26  re-installed as set out above. The gap sub  10  can then be returned to operation. 
     Unless the context clearly requires otherwise, throughout the description and the claims:
     “comprise”, “comprising”, and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.   “connected”, “coupled”, or any variant thereof, means any connection or coupling, either direct or indirect, between two or more elements; the coupling or connection between the elements can be physical, logical, or a combination thereof.   “herein”, “above”, “below”, and words of similar import, when used to describe this specification shall refer to this specification as a whole and not to any particular portions of this specification.   “or”, in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.   the singular forms “a”, “an” and “the” also include the meaning of any appropriate plural forms.   

     Words that indicate directions such as “vertical”, “transverse”, “horizontal”, “upward”, “downward”, “forward”, “backward”, “inward”, “outward”, “vertical”, “transverse”, “left”, “right”, “front”, “back”, “top”, “bottom”, “below”, “above”, “under”, and the like, used in this description and any accompanying claims (where present) depend on the specific orientation of the apparatus described and illustrated. The subject matter described herein may assume various alternative orientations. Accordingly, these directional terms are not strictly defined and should not be interpreted narrowly. 
     Where a component (e.g. a circuit, module, assembly, device, drill string component, drill rig system etc.) is referred to herein, unless otherwise indicated, reference to that component (including a reference to a “means”) should be interpreted as including as equivalents of that component any component which performs the function of the described component (i.e., that is functionally equivalent), including components which are not structurally equivalent to the disclosed structure which performs the function in the illustrated exemplary embodiments of the invention. 
     Specific examples of methods and apparatus have been described herein for purposes of illustration. These are only examples. The technology provided herein can be applied to contexts other than the exemplary contexts described above. Many alterations, modifications, additions, omissions and permutations are possible within the practice of this invention. This invention includes variations on described embodiments that would be apparent to the skilled person, including variations obtained by: replacing features, elements and/or acts with equivalent features, elements and/or acts; mixing and matching of features, elements and/or acts from different embodiments; combining features, elements and/or acts from embodiments as described herein with features, elements and/or acts of other technology; and/or omitting combining features, elements and/or acts from described embodiments. 
     The foregoing is considered as illustrative only of the principles of the invention. The scope of the claims should not be limited by the exemplary embodiments set forth in the foregoing, but should be given the broadest interpretation consistent with the specification as a whole.