Abstract:
A seal assembly, for sealing between a stationary conduit and a rotating conduit, comprises an upper gland assembly, a washpipe, and a lower gland assembly. The upper gland assembly is operable to engage the stationary conduit. A washpipe partially disposed within the upper gland assembly. An upper seal member is disposed within the upper gland assembly around a periphery of the washpipe. An upper packing ring is engaged with the upper gland assembly so as to compress the upper seal member into sealing engagement with the washpipe. A lower gland assembly is disposed about the washpipe and operable to engage the rotating conduit. A lower seal member is disposed within the lower gland assembly and is compressed into sealing engagement with the washpipe by a lower packing ring that is engaged with the lower gland assembly. The engagement of the packing rings with their respective gland assemblies is independent of the engagement of the gland assemblies and the conduits.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority to U.S. Provisional Patent Application No. 60/795,601, filed Apr. 27, 2006, and titled “Apparatus for Interconnecting and Sealing Between Fixed and Rotating Conduits and Method of Installing Same,” which is hereby incorporated by reference herein for all purposes. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable. 
   BACKGROUND 
   The present invention relates generally to apparatus for providing high pressure fluid communication between generally aligned conduits that are rotatable relative to one another using pressure activated seals. In particular, but not exclusively, the disclosure relates to devices for sealing a wash pipe assembly between a fixed and rotating conduit as used in rotary drilling operations. 
   In applications requiring the transmission of fluid under relatively high pressure, it is sometimes necessary to interconnect a rotating conduit with a stationary conduit and to seal the connection therebetween. One such application is in drilling operations in which a fixed-to-rotating interface is located in apparatus that is supported from the derrick, and which may take the form of a swivel, a top drive unit, or similar device. The seal between the fixed and rotating parts typically includes pressure activated, elastomeric annular seals or packing rings that must be changed when seal wear or failure occurs. Seals in common use today typically must be replaced every few hundred hours of use. This replacement involves time consuming and sometimes dangerous procedures in which the replacement components and a worker are hoisted from the drill floor up to the equipment that houses the seals that are to be replaced. While suspended at a height that may be twenty to thirty feet or more above the drill floor, the worker typically utilizes a sledgehammer to hammer open certain unions allowing removal of the washpipe assembly that contains the seals. Thereafter, new seals are inserted into the assembly, and the assembly containing the new seals is hammered into place. Some conventional seal assemblies also require the use of a pressurized fluid in order to energize the pressure-activated seals once the assembly has been installed in the swivel or top drive. This again is accomplished while the worker dangles from support lines high above the drill floor. The change out of the washpipe and seal assembly is thus complicated and time consuming, and includes the danger of the worker dropping a heavy sledgehammer onto workers or equipment below. 
   One common washpipe assembly houses a plurality of redundant annular seals that, during replacement, are stacked in position in the seal gland housing while the worker is suspended above the drill floor. In other conventional assemblies, as mentioned above, the seals are pre-packed in a washpipe assembly before the assembly is hoisted to the swivel above the drill floor. However, in order for the assembly to be coupled into the conduits, the seals must be manipulated in order to energize the seals and cause them to sealingly engage the washpipe, or to allow coupling nuts to slide upon the washpipe assembly and engage the appropriate adjacent conduit. This may be accomplished by means of pressurized fluid as described, for example, in U.S. Patent Application Publication No. US2005/0242512, incorporated herein by reference. The pressurized fluid, such as air, may also be used to set or energize the seals. The use of pressurized fluid requires the worker to also carry or be provided a line for supplying the pressurized fluid. As will be understood, the complications associated with handling the washpipe assembly itself, in addition to pneumatic lines and a sledgehammer, make the operation awkward and time consuming to perform twenty or more feet above the drill floor. Further, given that drilling must cease during this replacement procedure and that drilling costs may be thousands of dollars per hour, it is desirable that the washpipe assembly be changed as quickly as possible, but with personnel safety a priority. 
   Accordingly, it would be an advance in the art if a more convenient and pre-energized or ready-to-install washpipe assembly was available so as to minimize certain safety concerns and speed up to the process of changing failed seals. 
   SUMMARY OF THE PREFERRED EMBODIMENTS 
   In one embodiment, a seal assembly, for sealing between a stationary conduit and a rotating conduit, comprises an upper gland assembly, a washpipe, and a lower gland assembly. The upper gland assembly is operable to engage the stationary conduit. A washpipe partially disposed within the upper gland assembly. An upper seal member is disposed within the upper gland assembly around a periphery of the washpipe. An upper packing ring is engaged with the upper gland assembly so as to compress the upper seal member into sealing engagement with the washpipe. A lower gland assembly is disposed about the washpipe and operable to engage the rotating conduit. A lower seal member is disposed within the lower gland assembly and is compressed into sealing engagement with the washpipe by a lower packing ring that is engaged with the lower gland assembly. The engagement of the packing rings with their respective gland assemblies is independent of the engagement of the gland assemblies and the conduits, thus allowing the seals to be engaged with the washpipe independently of the location of the seal assembly 
   Embodiments of the present invention include a method for installing a washpipe assembly by first assembling a washpipe assembly on an assembly fixture so that both an upper and lower gland assembly are sealingly engaged with a washpipe. The washpipe assembly is then positioned in alignment with a stationary conduit and a rotatable conduit and coupled to both the stationary conduit and the rotatable conduit. The sealing engagement of the upper and lower gland assemblies with the washpipe is independent of the washpipe assembly being coupled to the stationary and rotatable conduits. 
   The present disclosure describes a combination of features aimed at overcoming various shortcomings of prior devices. The various characteristics described above, as sell as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments, and by referring to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more detailed description of the preferred embodiments of the present invention, reference will now be made to the accompanying drawings, wherein: 
       FIG. 1  is a cross-sectional view of a washpipe assembly disposed between a stationary and rotating conduit, portions thereof being shown in schematic form; 
       FIG. 2  is perspective view of one embodiment of a washpipe assembly constructed in accordance with embodiments of the current invention; 
       FIG. 3  is a longitudinal cross-sectional view of the washpipe assembly shown in  FIG. 2 . 
       FIG. 4  is a cross-sectional view of the lower seal gland housing of the washpipe assembly shown in  FIGS. 2 and 3 ; 
       FIG. 5  is a cross-sectional view of the upper seal gland housing of the washpipe assembly shown in  FIGS. 2 and 3 ; 
       FIG. 6  is perspective view of a fixture employed in energizing the seals of the washpipe assembly shown in  FIGS. 2-5 ; 
       FIG. 7  is a top view of the fixture shown in  FIG. 6 ; 
       FIG. 8  is a cross-sectional view of the fixture shown in  FIG. 7 ; 
       FIG. 9  is a perspective view of an assembly tool; 
       FIG. 10  is a perspective view of a torque-imparting bumper bar; 
       FIG. 11  is a cross-sectional view of the washpipe assembly of  FIGS. 2 and 3  in a first stage of assembly; 
       FIG. 12  is a cross-sectional view of the washpipe assembly of  FIGS. 2 and 3  in a second stage of assembly; 
       FIG. 13  is a cross-sectional view of the washpipe assembly of  FIGS. 2 and 3  in a third stage of assembly; and 
       FIG. 14  is a perspective view of the washpipe assembly of  FIGS. 2 and 3  positioned within a swivel housing. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Disclosed is an apparatus for interconnecting a fixed or stationary conduit to a conduit intended to rotate relative to the fixed conduit, and for sealing between the fixed and rotating conduits to prevent pressurized fluid from escaping from the intended path through the aligned conduits. One particular application for the apparatus disclosed herein is as a washpipe assembly as used in the drilling of oil and gas wells. In particular, in such application, a stationary conduit that extends from a conventional gooseneck is aligned with, but spaced apart from, a conduit forming a part of a rotatable swivel assembly. Pressurized drilling fluid is conveyed through the gooseneck and stationary conduit and into the rotating conduit. The assembly disclosed herein interconnects the aligned conduits and allows drilling fluid to be conducted therethrough by maintaining a dynamic seal as one conduit rotates relative to the fixed conduit. 
   Referring to  FIG. 1 , a washpipe assembly  10  is shown disposed between a fixed conduit  18  and a conduit  20  that is adapted for rotation relative to fixed conduit  18 . Washpipe assembly  10  generally includes lower gland assembly  12 , upper gland assembly  14 , and washpipe  16  that is disposed through apertures in the lower and upper gland assemblies  12 ,  14  and which is aligned with the fluid passageways in upper and lower conduits  18 ,  20 . In general, the upper gland assembly  14  fixes the upper end of washpipe  16  to stationary conduit  18  and prevents fluid from escaping therebetween. Likewise, lower seal gland assembly  12  retains the lower end of washpipe  16  in alignment with rotating conduit  20  and is attached to conduit  20  such that lower gland assembly  12  rotates with rotating conduit  20 . Lower gland assembly  12  includes dynamic seals (described below) which rotate about stationary washpipe  16  and prevent pressurized fluid from passing from the interior passageway of the washpipe. 
   The components of washpipe assembly  10  are best shown in  FIGS. 2 and 3  and comprise lower gland assembly  12 , lower gland nut  13 , upper gland assembly  14 , and washpipe  16 . When assembled, upper gland assembly  14  is disposed about the upper end of washpipe  16  and lower gland assembly  12  is disposed about the lower end of the washpipe. Lower gland nut  13  provides threaded region  51  that is operable to connect to a correspondingly threaded region of rotating conduit  20  (see  FIG. 1 ). Upper gland assembly  14  provides threaded region  49  that is operable to connect washpipe assembly  10  to rotating conduit  20  and stationary conduit  18 , respectively. 
   As best shown in  FIGS. 3 and 4 , the lower gland assembly  12  includes a lower gland housing  22 , threaded set ring  24 , intermediate packing rings  26 ,  27 , upper packing ring  28 , and a series of annular resilient packing rings  30 . Lower gland housing  22  includes a top or base portion  23  and a cylindrical sleeve-like portion  25  extending therefrom, and includes inner and outer surfaces  32 ,  33 , respectively. The outer surface  33  of the top portion includes four extending lugs  36 , as described in more detail below, and an annular, outwardly-extending flange  38 . 
   As best shown in  FIG. 4 , the inner surface  32  of the lower housing  22  includes an internal threaded portion  34  for engaging corresponding threads formed on the radially-outer surface of threaded bottom packing ring  24 . The lower facing surface  35  of threaded bottom packing ring  24  includes a groove or seal gland  39  for retaining annular O-ring seal  40 , as well as six tool-engaging bores  41  described more fully below. Mounted in an aperture formed in sleeve portion  25  of the housing  22  is grease fitting  29  allowing for the introduction of grease within the seal assembly. Grease fitting  29  is installed through the housing and attached thereto to provide a means for lubricating between the washpipe and the seal surfaces. The grease fitting is a standard fitting having a check valve to allow grease to enter the assembly but restricting the outward flow of grease. Lower gland assembly  12  further includes a stop  21  that is intended to prevent damage to grease fitting  29  when lower gland nut  13  is raised when washpipe assembly  10  is lifted for installation. Upon assembly, upper packing ring  28 , intermediate packing rings  26 ,  27 , and bottom threaded packing ring  24  are positioned in the interior of the housing with annular resilient packing rings  30  disposed between each packing ring. Threaded bottom packing ring  24  is threaded onto interior threads  34  of the inner housing surface  32  to energize seals  30  and causing them to sealingly engage washpipe  16  once ring  24  is fully seated. 
   Referring to  FIGS. 3 and 5 , the upper gland assembly  14  is shown to include upper gland housing  42 , threaded upper packing ring  43 , and annular resilient packing ring  44 . Upper gland housing  42  includes a base portion  45  and a cylindrical portion  46  extending therefrom. The upper gland housing  42  includes inner and outer surfaces  47 ,  48 , respectively. Formed on the uppermost end of the inner surface  47  is a threaded region  49  for engaging a correspondingly-threaded extension (not shown) of the stationary conduit  18 . The inner surface  47  further includes a second threaded segment  50  adjacent to the base  45  for engaging a correspondingly threaded segment of the threaded upper packing ring  43  (also referred to herein as top or upper set ring  43 ). The outer surface  48  of base portion  45  includes four downwardly-extending lugs  52 , and cylindrical portion  46  of housing  42  includes radial tool-engaging recesses  53  as will be described in more detail below. 
   Upon assembly, annular resilient packing ring  44  is disposed adjacent to the base portion  45  of the upper gland housing, and the threaded upper packing ring  43  is threaded onto threaded portion  50  of the housing. As best shown in  FIG. 5 , the facing surface  54  of the threaded upper packing ring  44  includes a seal gland or groove  55  which, in turn, houses an O-ring seal  56 . Also included in facing surface  54  are six tool-engaging bores  57  described in more detail below. As best shown in  FIG. 2 , the upper end of washpipe  16  includes a plurality of milled grooves  90  extending longitudinally along the outside of the washpipe and spaced apart about the washpipe&#39;s circumference. Additionally, as shown in  FIGS. 2 and 3 , a circumferential groove  92  that intersects milled longitudinal grooves  90  is formed near the top of the washpipe for receiving a snap ring  93  as described more fully below. 
   As best shown in  FIGS. 2 and 3 , lower gland nut  13  includes an extending sleeve portion  60 , and a collar portion  61 . Collar portion  61  comprises two semicircular segments  62   a ,  62   b  that are connected to sleeve portion  60  by fastener  63  as shown in  FIG. 2 . The collar portions  62   a ,  62   b  include a downwardly-extending flange or lip  64  that engages the outer surface of sleeve  60 . Each end of semicircular segments  62   a ,  62   b  includes a machined recess  62   c  to provide clearance for grease fitting  29  and for stop  21 , as best shown in  FIG. 2 . Each semicircular collar portion  62   a ,  62   b  includes a handle or grasping member  65 . In this arrangement, lower nut  13  may slide relative to housing  22  of lower gland assembly  12  until such time that the lower gland nut  13  threadedly connects the washpipe assembly  10  to rotating conduit  20 . Formed in the sleeve portion  60  of the lower gland nut  13  is a plurality of radial tool-engaging recesses  37  for use during the installation of the assembly. 
   In order to energize the packing seals  30 ,  44  while the assembly is conveniently located on the rig floor, there is provided a compression fixture  70  best show in  FIGS. 6-8 . As shown, the fixture  70  includes a base plate  72  and a generally cylindrical support pedestal  74  extending upwardly therefrom. A mounting ring  76  is attached to the support pedestal and includes a central threaded bore  78  and a circular recess  80  for receiving a pilot sleeve  82 . The pilot sleeve  82  seats in recess  80  and extends upwardly from the ring  76 . Sleeve  82  is affixed to ring  76  by a central fastener  86 , which includes a threaded portion  87  that engages threaded segment  78  of mounting ring  76 . The pilot sleeve  82  has an outer diameter slightly less than the inside diameter of the washpipe  16 . 
   The mounting ring  76  includes six upwardly extending locating pins  100  sized and spaced so as to be received within the tool-engaging bores  41  ( FIG. 4 ) formed in lower threaded packing ring  24  of the lower gland assembly  12 . As described in more detail below, the compression fixture  70  is provided and employed in order to energize the seals  30 ,  44  prior to lifting the washpipe assembly  10  from the rig floor, such that the assembly  10  is ready-to-install without additional steps having to be taken to energize the seals after the worker has been lifted above the rig floor. 
   The assembly of the washpipe assembly is shown in  FIGS. 11-13 . Referring to  FIG. 11 , sleeve portion  25  of lower gland housing  22  is disposed through the central bore of the bottom gland nut  13 . Semicircular collar portions  62   a ,  62   b  are then attached to the upper surface of the gland nut sleeve  60  via fasteners  63  (see  FIG. 2 ). The downwardly extending lip  64  formed on the lower surface of the collar portions extends over and captures the annular flange  38  extending from the outer surface of the lower gland housing  22 . Handles or grips  65  extend from the collar portions. In this position, gland nut  13  may slide relative to lower gland housing  22  to the limits permitted by the intersection of collar portions  62   a ,  62   b  with annular flanges  38 . 
   Prior to installation on fixture  70  (as shown in  FIG. 11 ) lower gland housing  12  is inverted and positioned such that the lugs  36  rest against a work surface and the opening that retains the packing seals and rings is upwardly disposed. The uppermost packing ring  30  is then placed in the housing in the position shown in  FIG. 4  such that its V-shaped annular extension is received by and mates with the correspondingly V-shaped annular recess formed in the inner surface  32  of the housing at base  23 . The upper packing ring  28  is next installed. In turn, the intermediate packing seals  30  and intermediate packing rings  26 ,  27  are sequentially stacked within the housing as shown in  FIG. 4 . Finally, the lowermost packing seal  30  and lower threaded packing ring  24  are installed. The lower threaded packing ring  24  is threaded by hand into engagement with the threaded portion  34  of the housing. At this stage of the assembly, ring  24  is not fully seated and, consequently, packing rings  30  are not yet set or energized. 
   Lower seal gland housing  22  is next inverted again such that lugs  36  face upward and washpipe  16  is then positioned within the central bore of lower seal gland housing  22  so that milled slots  90  (see  FIG. 2 ) are at the top, and extend outwardly from the lower gland housing  22 . At this step of the assembly procedure, the lower gland housing  22  is placed on the compression fixture  70  such that the locating pins  100  on the fixture  70  mate with the bores  41  formed in the lower set ring  24 , as is shown in  FIG. 11 . The packing seals  30 , at this step, have not been energized such that the washpipe  16  may slide through the opening in the lower gland housing  22  without difficulty. Top gland housing  42  is then disposed over the top of the washpipe  16 . 
   In this position, the downwardly extending lugs  52  of the top seal gland housing are oriented to engage with the corresponding upwardly extending lugs  36  from the lower gland assembly  12  such that rotation of the upper gland housing  42  will rotate the lower gland housing  22  via engagement of lugs  52  and  36 . The upper housing  42  is then rotated by use of bumper bar  120  (see  FIG. 10 ) which, in turn, causes the lower housing  22  to rotate. Because set ring  24  is fixed into the compression fixture  70 , the lower housing  22  is rotated relative to the stationary set ring  24  causing the ring to be tightened within the housing and causing the ring  24  to set, or energize, the resilient packings  30  against the outer diameter of washpipe  16 . 
   Referring now to  FIG. 12 , upper set ring  43  and upper packing seal  44  are disposed within upper housing  42 . Tool-receiving bores  57  of upper set ring  43  are upwardly-disposed. Rotation of the upper set ring  43  is accomplished by use of an assembly tool  102 , such as is shown in  FIG. 9 . The tool  102  includes six extending lugs  104  sized and positioned so as to correspond to the tool-receiving bores  57  in the upper set ring  43 . The assembly tool further includes a cylindrical extension  106  having radially-positioned tool-receiving bores  108 . To set the top ring  43  and energize the upper packing seal  44 , the assembly tool  102  is disposed in the interior of the upper gland housing  42  such that the lugs  104  mate with the tool-receiving bores  57  in the set ring  43 . Using the bumper bar  120  ( FIG. 10 ) or another tool, the assembly tool  102  is rotated causing the set ring  43  to fully thread and bottom out against the inner surface  47  of the gland housing, thereby energizing seal  44 . The assembly tool  102  is the removed. 
   Referring now to  FIG. 13 , O-ring seal  56  is disposed in the seal groove  55  and the lug collar  95  is next installed. Lug collar  95  includes a slotted inner surface enabling its surface to mate with the longitudinal slots  90  of the washpipe end. The lug collar  95  is positioned below the snap ring groove  92  and the snap ring  93  is then installed in circumferential groove  92  to retain the lug collar  95  on the washpipe. At this point, the washpipe assembly  10  is ready to be installed with all pressure-activated packing seals energized. Referring back to  FIG. 2 , prior to installation, O-ring  40  is installed in seal groove  39  in the facing surface  35  of lower threaded packing ring  24 , and upper annular O-ring seal  98  is positioned in seal groove  99  formed in the upper surface of lug collar  95 . 
   Referring now to  FIG. 14 , when it is necessary to change out the washpipe assembly, rig personnel are hoisted up to the swivel or top drive in order to remove the previously-installed washpipe assembly  10 . After that assembly has been removed, the stand-by and ready-to-install washpipe assembly  10  is lifted into position. The washpipe assembly  10  is then positioned between the stationary conduit  18  of the gooseneck and the rotating conduit  20  in the swivel. Because the rotary seals have previously been energized, no special pressurizing need be performed by the worker while suspended above the rig floor and thus no pneumatic or hydraulic lines need be carried or manipulated. Instead, installation is accomplished by first hand-threading the top gland housing  42  onto the threaded portion of the downwardly-extending conduit  18  and hand-threading the bottom gland nut  13  onto the upwardly-extending threaded conduit  20  of the swivel assembly. After hand tightening these components, the worker inserts the reduced diameter end portion of bumper bar  120  into the radial tool-engaging recesses  53 ,  37  formed in the upper gland housing and lower nut  13 , respectively, and completes tightening the nuts by manipulating the bumper bar as shown in  FIG. 11 . Should the worker lose his grip on the tool, a connected tether prevents the tool from falling to the rig floor. Upon completion of the installation, drilling operations can commence again. 
   While preferred embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit or teaching herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the system and apparatus are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims which follow, the scope of which shall include all equivalents of the subject matter of the claims.