Patent Publication Number: US-7905279-B2

Title: Combination whipstock and seal bore diverter system

Description:
BACKGROUND 
     Whipstock and seal bore diverters are well known pieces of equipment in the hydrocarbon recovery industry. Each has its purpose and requires that it be run in the hole to be used. Heretofore, these tools were run in the hole separately as they are separate tools and do not have complementary shapes to one another. Whipstocks are used to divert a milling bit through a wall of the primary borehole through which the mill is run from a location uphole. This is, of course, the beginning of a lateral borehole. The whipstock may or may not include hardened surfaces at the diverter portion thereof to resist the milling bit. A seal bore diverter is used to divert a junction or junction liner into the already drilled lateral borehole. The diverter face angle may be different to ensure that a later run junction or junction liner is directed through a large portion of the window exit. The seal bore diverter may or may not have hardened surfaces on the diverter face. Because of the distinctness of the tools, they are both required and are run separately. In view of the desirability of greater efficiency and the consequent improved monetary return, the art would well receive a system that reduces the number of runs necessary and the length of time the lateral borehole remains exposed to possible collapse or contamination from borehole fluid. 
     SUMMARY 
     A combination whipstock and seal bore diverter system includes a whipstock; and a diverter configured to receive and support the whipstock in a selected orientation, the system being installable in a single run in a borehole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
         FIG. 1  is a perspective view of one embodiment of a combination whipstock and seal bore diverter system as disclosed herein; 
         FIG. 2  is a perspective view of the system illustrated in  FIG. 1  after the milling bit has created a window exit, the whipstock has been recovered, and a junction or junction liner is installed; 
         FIGS. 3-5  are an elongated sectional view of the system illustrated in  FIG. 1 ; 
         FIG. 6  is a perspective view of the retrievable whipstock portion of the system illustrated in  FIG. 1 ; and 
         FIG. 7  is an enlarged sectional view of a portion of an interengagement body of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a combination whipstock and seal bore diverter system  10  is illustrated. The system  10  includes a whipstock  12 , a diverter  14 , a joint  16 , a connection ring  18 , and a connector  20 . These components are operably connected to one another to form the combination whipstock and seal bore diverter system  10  disclosed herein. One of the features of the system  10  is that the whipstock  12  is separable from the diverter  14 . This allows the whipstock  12  to be retrieved to surface and leaves the diverter  14  installed and oriented to receive a later installed junction. The junction will then complete the section of a wellbore (not shown) in which the system  10  is initially installed. While separability has been mentioned above, reintroduction of a whipstock  12  to the diverter  14  is also possible with the system  10 . In order to promote the separability and reintroduction, the whipstock  12  comprises several components that allow separation from and re-engagement with the diverter  14  under selected conditions. 
     Referring to  FIG. 2 , the system  10  is illustrated post separation of the whipstock  12  and post installation of a separately run junction  22 , such as a Hydrasplit™ junction, commercially available from Baker Oil Tools, Houston, Tex. under Material Number H289220000. The junction  22  comprises a primary leg  24  and a lateral leg  26 . As illustrated in  FIG. 2 , the lateral leg  26  is diverted from the primary bore by diverter face  28  of diverter  14 , while the primary leg  24  is received within a bore of diverter  14 , illustrated and described later in this document, and is fluidly connected with an inside diameter flow pathway  30  extending through the system  10  (in sections, demarcated in  FIGS. 3 and 5  as  30   a - 30   g ) and defined in part by connector  20 . Connector  20  is configured to be received in an anchor  51  (see  FIG. 5 ) that has been previously installed and oriented or that is run in conjunction with system  10 , but in any event, that is conventional. The lateral leg  26 , having been diverted by the diverter face  28 , will extend into a lateral borehole (not shown) that has been drilled using the whipstock  12  before retrieval thereof to the surface. It is to be appreciated that the positioning and angle of the diverter face  28  is set such that the lateral leg  26  exits the primary borehole (not shown) at a widest point of a window (not shown) that has been milled in a casing (not shown) of the primary borehole. This improves the likelihood that the lateral leg  26  will indeed find its mark without becoming impacted by an edge of the window. 
     Returning to  FIG. 1 , it is to be appreciated that the system  10 , built at a surface location, may be run into the primary borehole, subsequent to the installation of an anchor or in conjunction with the anchor, to a particular selected depth and orientation in the borehole where it is desired to create a lateral borehole. This, of course, is related to accessing a formation area determined to contain a target hydrocarbon fluid. Whether the anchor is run and installed before the system  10  or in conjunction with the system  10 , the anchor is set in the borehole at the desired depth and with a particular orientation in a conventional way. The system  10  is oriented to the anchor orientation. 
     Referring to  FIGS. 3 ,  4 , and  5 , an elongated sectional view of the diverter  14  provides an understanding of how the components of system  10  function together. Beginning with  FIG. 5 , the downhole most portion (in one embodiment; it is to be understood that the device could also be built upside down) of the diverter  14  is illustrated in an enlarged view. It will be appreciated from this view that connector  20  extends through connection ring  18  and joint  16  and defines the pathway  30 , as stated above. It should also be noticed in this view that the pathway  30   g , which is centralized at the downhole end of the connector  20 , includes a jog  32  to an intermediate pathway  30   f . The intermediate pathway  30   f  is offset relative to the axis of the connector  20 , but the fluid communication between pathway  30   g  and pathway  30   e  is still enabled. Pathway  30   e  being offset is to accommodate the positioning of pathway  30   a  through  30   e . Pathway sections  30   a  through  30   e  are positioned generally parallel to the axis of the system  10  but offset therefrom to allow for the diverter face  28  (see  FIG. 2 ) and a whipstock face  36  (See  FIG. 6 ). Because the faces  28  and  36  remove material from the whipstock  12  and diverter  14  in sufficient quantity to have otherwise breached the pathway  30 , the offset is necessary for functionality of the system  10 . The pathway  30 , in one embodiment, is thus offset from the axis of the system  10  as much as is practicable, leaving about ¼ inch of material of the diverter at the portion of that component opposite the diverter face  28  to define the pathway  30 . Reference to  FIGS. 3-5  makes the pathway  30  clear, with numerals identifying each portion thereof on the various figures. 
     Referring back to  FIG. 5 , the system  10  includes a connection point  40  between the joint  16  and the diverter  14 . The components are in this embodiment, threadedly connected at thread  42  but further include a spline sub  44 . The spline sub  44  features a single position spline configuration. The joint  16  and the diverter  14  fit together in only one way. This configuration is beneficial in that the offshore baskets used to transport materials restrict the length of components that will fit. The spline sub facilitates reassembly on a rig floor while ensuring that the orientation of the whipstock  12  and diverter  14  relative to components below the diverter (such as a shear disconnect sub, polished bore receptacle seal assembly, and packer anchor, all not shown) is maintained. The spline sub  44  must also provide a fluid passageway  48  to connect the pathway  30   e  to the pathway  30   f.    
     Continuing to move in the uphole direction, in this embodiment, and now referring to  FIGS. 4 and 5 , a cover sleeve  50  is illustrated disposed within the diverter  14 . The cover sleeve  50  telescopically receives a seal protector sleeve  52  subsequent to release of a release member  54 , which may be a shear ring (as illustrated) in some embodiments, and in one specific embodiment requires a compressive load of about 20,000 pounds to release. Action of the release member  54  is to maintain the seal protector sleeve  52  in the proper position (illustrated) until the junction  22  (see  FIG. 2 ) is installed, at which point the primary leg  24  of the junction  22  lands on the seal protector sleeve  52 , loading the same axially until the release member  54  releases (e.g. shears) and allows the seal protector sleeve  52  to move telescopically into the cover sleeve  50  thereby exposing a plurality of seal stacks  56  to sealingly engage with the primary leg  24  (see  FIG. 2 ). In one embodiment, the seals are all maintained in position by a top sub  58 , a seal sub  60 , a bottom seal sub  62 , a bottom sub  64 , a seal holder  66 , and a seal keeper ring  68 . It should be understood that the exact configuration of components to maintain the seal stacks  56  in position may be modified without departing from the scope of the invention. All that is required is that a seal system be provided to fluid sealingly engage the primary leg  24  of the junction  22  (see  FIG. 2 ) at the appropriate time. It is desirable that the seals be protected from debris or physical damage prior to landing of the primary leg  24  by a suitable protector, the seal protector sleeve  52  being one possible option. Such may be accomplished in many configurations. The seal holder  66  in this embodiment is a squared off structure to easily slip into the diverter  14  but to securely hold the seal structure  58 - 64  in place within diverter  14 . In one embodiment, the seal holder  66  is itself pinned to the diverter  14  at pin  70 , which may be a threaded fastener, for example. Top sub  58 , apart from providing structure for associated seal stacks  56 , also provides a seal bore  72  for sealing receipt of a portion of the whipstock  12 . 
     Referring to  FIGS. 4 ,  6 , and  7 , the whipstock  12  comprises two major components in the illustrated embodiment. These are a scoop body  74  and an interconnection body  76 . These components are received in operable communication with the diverter  14  by insertion of the interconnection body  76  into a receiving bore  78  of diverter  14  and a base  80  of the scoop body  74  coming into contact with an end  82  of the diverter  14  (see  FIG. 3 ). A spool sub  86 , extending from interconnection body  76  (which also houses pathways  30   c  and  30   d ), supports one or more seals  88 , such as o-rings, to sealingly engage seal bore  72 . 
     The scoop body  74  and the interconnection body  76  are connected to one another by a fastening process, such as by welding, or by mechanical configuration. It is to be noted that in the illustrated embodiment, the interconnection body  76  also is scalloped at surface  90  to match surface  36  for a smooth transition of a mill (not shown) being diverted by the scoop body  74  when the system  10  is in use. 
     Referring to  FIG. 7 , the spool sub  86  is received within one end of the interconnection body  76 . In the illustrated embodiment, the spool sub  86  is threadedly connected to the interconnection body  76  as illustrated by thread  92 . It will be appreciated that other configurations resulting in the connection are substitutable. When the connection is a threaded one, as shown, an arrangement to prevent unthreading is desirable. One embodiment of such an arrangement is shown as at least one ball, and here two balls  94 , held in place by set screws  96 . The spool sub  86  provides for a flow of fluid therethrough while inhibiting flow therearound with seals  88  in contact with the seal bore  72 . It is important that fluid be able to flow through the spool sub  86  in order to prevent floating of the system  10 . Equally as important, however, is that fluid only flows in one direction, so that debris from the milling operation to take place upon the whipstock face  36  cannot migrate through the spool sub  86 . Dispatching this duty is a float valve assembly  98  (a check valve arrangement), which is commercially available from Baker Oil Tools, Houston, Tex. under Part Number H480131200. Fluid flowing through the assembly  98 , is exhausted to pathway  30   a  (an annular space defined at the receiving bore  78 ) just beyond a seal stack  56  through pathway  30   b . Further, the interconnection body  76  includes a guide  100  that assists in controlled axial movement of the interconnection body  76  and a debris exclusion configuration  102 , such as a wire brush to prevent debris migration from the whipstock face  36  into the seal area of the diverter  14 . 
     For retrievability of the whipstock  12 , a collet  104  having a profile  106  thereon is disposed about the interconnection body  76  and maintained in position there by a pair of cover rings  108  and a retaining ring  110 , other similarly functioning arrangements being substitutable without departing from the scope of the invention. The collet profile  106  is complementary to a profile receptacle  112  at the bore  78  (see  FIG. 4 ). The collet  104  is configured to release at a predetermined pull load and thus allows retrieval of the whipstock  12  and all of its components. The retrieval is effected by a pull load on a locking retrieval slot  114  (see  FIG. 1 ). 
     In use, the combination whipstock and seal bore diverter system  10  is affixed to a milling assembly (not shown) or run in the hole on its own. The system  10  is oriented and a mill is brought into contact with whipstock face  36  to divert the mill through a casing wall and thereby create a window. While creating the window, a substantial amount of debris will be created, but that debris is prevented from migrating into the diverter  14  by debris excluder  102 , valve  98  (see  FIG. 7 ), and seal stacks  56  (see  FIG. 4 ). After the window is milled, the whipstock  12  is retrieved to surface by latching thereto through the slot  114  and pulling thereon in an amount exceeding the release amount required to release the release mechanism, which in the illustrated embodiment is collet  104 . Once the collet  104  releases from profile receptacle  112 , the whipstock  12  will begin to move uphole. In a separate run, a junction, such as junction  22 , is run in the hole so that primary leg  24  stabs into the diverter  14  and engages seal stacks  56  subsequent to landing upon the seal protector sleeve  52  and shearing the release member  54  allowing the seal protector sleeve  52  to move into the cover sleeve  50 . The primary leg  24  then is sealed to the diverter  14 . While the sealing is occurring, the lateral leg  26  of the junction  22  is being diverted out of the window (not shown) by the diverter face  28 . Once the junction  22  is fully seated in the diverter  14 , the operation is complete. 
     The configuration disclosed herein provides many benefits to the hydrocarbon recovery industry, such as but not limited to: reduction of the number of trips in the hole necessary to successfully create a lateral borehole and complete a junction, thereby reducing costs and rig time; reduction of the time that a newly drilled junction is open, thereby greatly enhancing the likelihood that the junction will remain open long enough to complete the operation; ability to position the seal bore diverter (herein denoted as diverter  14 ) prior to window formation to ensure proper orientation and to avoid problems associated with debris in the hole when diverter is traditionally subsequently located; ability to retrieve the whipstock  12  and replace it with a new one, if conditions require, without having any concern about consistent orientation; release member  54  in diverter  14  provides a positive indicator that the junction  22  is landed; and the spline sub  44  allows for the system to be disassembled for shipping without concern regarding proper realignment when re-assembled on a rig floor. 
     While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitations.