Abstract:
A method of well completion includes: introducing a hydraulic set liner hanger assembly into a cased main bore, the hydraulic set liner hanger assembly comprising a first pipe assembly and a second pipe assembly coupled to the hydraulic set liner hanger assembly, the first pipe assembly comprising a first seal coupled to a distal end of a first pipe, the second pipe assembly comprising a second seal coupled to a distal end of a second pipe, the second pipe being longer than the first pipe and the second seal having a larger outer diameter than the first seal; advancing the hydraulic set liner hanger assembly through the cased main bore, the second seal abutting a deflecting surface of a hollow diverter located in the cased main bore and being directed into a second lateral bore to provide a seal between a second liner received in the second lateral bore and the second pipe, the first seal passing through the hollow diverter to provide a seal between a first liner received in a first lateral bore and the first pipe, the deflecting surface of the hollow diverter being located adjacent to the second lateral bore; and setting the hydraulic set liner in the cased main bore.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of priority of U.S. Provisional Patent Application No. 61/971,879 filed Mar. 28, 2014, which is hereby incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present application relates to lateral well completions. 
       BACKGROUND DISCUSSION 
       [0003]    In oil sands, a Steam Assisted Gravity Drainage (SAGD) process is typically used to produce oil. Before any oil is produced, well completion is performed on a drilled bore in order to prepare the well for production. Well completion is a time consuming process because equipment is deployed downhole in a particular order and in a number of steps. 
         [0004]    Well completion for multilateral wells is generally more complicated and more time consuming than well completion of a single well. However, well completion for multilateral wells typically takes less time than well completion of two or more single wells at different locations because only one completion and one surface location is required for each multilateral well. Multilateral wells typically result in a cost savings on a field development basis. In addition, a single surface location has additional cost savings due to reduced: surface infrastructure, surface disturbance, mobilization as well as reduced drilling cost to reach the production interval(s). In the case of SAGD, these savings may be significantly increased due to the high cost of surface infrastructure associated with steam injection activity. 
       SUMMARY 
       [0005]    In an aspect of the present disclosure, there is provided a method of well completion for a well comprising a first lateral bore and a second lateral bore, comprising: introducing a hydraulic set liner hanger assembly into a cased main bore, the hydraulic set liner hanger assembly comprising a first pipe assembly and a second pipe assembly coupled to the hydraulic set liner hanger assembly, the first pipe assembly comprising a first seal coupled to a distal end of a first pipe, the second pipe assembly comprising a second seal coupled to a distal end of a second pipe, the second pipe being longer than the first pipe and the second seal having a larger outer diameter than the first seal; advancing the hydraulic set liner hanger assembly through the cased main bore, the second seal abutting a deflecting surface of a hollow diverter located in the cased main bore and being directed into the second lateral bore to provide a seal between a second liner received in the second lateral bore and the second pipe, the first seal passing through the hollow diverter to provide a seal between a first liner received in the first lateral bore and the first pipe, the deflecting surface of the hollow diverter being located adjacent to the second lateral bore; and setting the hydraulic set liner in the cased main bore. 
         [0006]    In another aspect of the present disclosure, there is provided an apparatus for well completion comprising: a hydraulic set liner hanger assembly for deployment and setting in a cased main bore, the hydraulic set liner hanger assembly comprising a first pipe assembly and a second pipe assembly coupled to the hydraulic set liner hanger assembly, the first pipe assembly comprising a first seal coupled to a distal end of a first pipe, the second pipe assembly comprising a second seal coupled to a distal end of a second pipe, the second pipe being longer than the first pipe and the second seal having a larger outer diameter than the first seal; and a hollow deflector for deployment downhole of the hydraulic set liner hanger assembly, the hollow deflector comprising a deflecting surface located at an uphole end; wherein the second seal is deflectable into a second lateral bore for forming a seal with a second liner received in the second lateral bore by a deflecting surface of the hollow deflector and the first seal is receivable through the hollow deflector for forming a seal with a first liner received in the first lateral bore. 
         [0007]    Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Embodiments of the present application will now be described, by way of example only, with reference to the attached Figures, wherein: 
           [0009]      FIG. 1  is a schematic side view of an example multilateral well; 
           [0010]      FIG. 2  is a schematic side view of another example multilateral well; 
           [0011]      FIG. 3  is a simplified sectional view of a partially completed multilateral well being completed using a completion method according to an embodiment; 
           [0012]      FIG. 4  is view similar to  FIG. 3  further along in the completion method; 
           [0013]      FIG. 5  is an isometric view of a hollow diverter according to an embodiment; 
           [0014]      FIGS. 6A and 6B  are end views of a dual crossover of the hydraulic set liner hanger assembly of  FIG. 4 ; 
           [0015]      FIG. 7  is view similar to  FIG. 3  still further along in the completion method; 
           [0016]      FIG. 8  is view similar to  FIG. 3  including tubing in a completed well; 
           [0017]      FIG. 9  is a sectional view of a dual crossover showing the tubing of  FIG. 8  passing therethrough; 
           [0018]      FIG. 10  is simplified sectional view of a partially completed multilateral well being completed using a completion method according to another embodiment; and 
           [0019]      FIG. 11  is view similar to  FIG. 10  further along in the completion method. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. Also, the description is not to be considered as limiting the scope of the embodiments described herein. 
         [0021]      FIGS. 1 and 2  show examples of two multi-lateral well configurations  10  and  12 , respectively. Multilateral wells generally include two or more lateral bores that are drilled at different true vertical depths (TVDs) ( FIG. 2 ) or drilled at approximately the same true vertical depth (TVD) ( FIG. 1 ). Multilateral wells may also include a combination of lateral bores that are drilled at different TVDs and drilled at approximately the same TVD. The type of multilateral well that is selected is determined based on the geology, fluid properties, recovery scheme and geomechanical properties, for example, at the location. In oil sands, for example, multilateral wells including lateral bores that are drilled at approximately the same TVD may be used and completed according to the method and apparatus disclosed herein in order to retrieve oil at different locations within a single sand formation. 
         [0022]    Referring now to  FIG. 3 , a well  20  in a partially completed state is generally shown. The well  20  includes a main bore  22  that is lined with a cemented casing  24 . A first lateral bore  26  includes a first liner  30  and a second lateral bore  28  includes a second liner  32 . 
         [0023]    The first lateral bore  26  is drilled by running a bridge plug  36  followed by a whipstock  34  into the main bore  22 , milling a window through the casing  24  and drilling the first lateral bore  26 . The bridge plug  36  includes a sealing element  35  and slips  38  to maintain the position of the bridge plug  36  in the main bore  22 . The whipstock  34  is set against the bridge plug  36  to trigger a setting mechanism and is oriented to direct milling and drilling tools in a selected lateral direction. The first liner  30  is then run into the first lateral bore  26  along with a setting collar including a first polished bore receptacle (PBR)  40 . A landing depth of the first PBR  40  is recorded for use later in the completion operation. 
         [0024]    Alternatively, when constructing a new well, the first lateral bore may be drilled using conventional drilling methods. For example, the first lateral bore may be a continuation of the main bore that is drilled as a single well from the surface using geosteering methods, as would be understood by a person skilled in the art. In addition, the first lateral bore could be part of an existing horizontal well or a highly-deviated well. 
         [0025]    The second lateral bore  28  is drilled by running a whipstock packer  42 , followed by a whipstock (not shown) into the main bore  22 , milling another window through the casing  24  and drilling the second lateral bore  28 . The whipstock packer  42  includes a sealing element  43  and slips  45  to fix the whipstock packer  42  in the main bore  22 . A pipe  44  is coupled to a downhole end of the whipstock packer  42  and a hollow diverter part  47  is received in an uphole end thereof. The pipe  44  includes a seal assembly  46  that is received in the first PBR  40  to form a seal therewith. The whipstock (not shown) is supported by the whipstock packer  42  and oriented to direct milling and drilling tools in a selected lateral direction. The second liner  32  is then run into the second lateral bore  28  along with a setting collar  48  including a second polished bore receptacle (PBR)  50 . A landing depth of the second PBR  50  is recorded for use later in the completion operation. The whipstock (not shown) is removed from the main bore  22  following the milling, drilling and liner setting operations for the second lateral bore  28 . 
         [0026]    A method of deploying a first pipe and a second pipe to form seals with first and second liners of first and second lateral bores  26 ,  28  in a single operation will now be described with reference to  FIGS. 4 to 8 . 
         [0027]    First, a hollow deflector  52  is run down the main bore  22  and coupled to the whipstock packer  42 . As shown in  FIG. 5 , the hollow deflector  52  includes an opening  55  extending therethrough and a deflecting surface  54  at an uphole end thereof. The deflecting surface  54  is positioned adjacent to the second lateral bore  28 . A hydraulic set liner hanger assembly  56  is then introduced into the main bore  22 . 
         [0028]    The hydraulic set liner hanger assembly  56  includes a hydraulic set liner hanger  58 , a dual crossover  60  including an inlet portion  63  and an outlet portion  67 , an inlet pipe string  65  coupled to the inlet portion  63  of the dual crossover  60  and a first pipe assembly  66  and a second pipe assembly  68  coupled to first and second outlets  69  and  71 , respectively, of the outlet portion  67  of the dual crossover  60  by threaded connections, for example. As shown, the hydraulic set liner hanger  58  is fixed in the main bore  22  by a sealing element  57  and slips  59  and the dual crossover  60  is coupled below the hydraulic set liner hanger  58  by a threaded connection, for example. The first pipe assembly  66  is aligned with a first bore  62  of the dual crossover  60  and the second pipe assembly  68  is aligned with a second bore  64  of the dual crossover  60 . As shown in  FIG. 6A , the first bore  62  may be offset from the second bore  64  relative to a central axial plane through the dual crossover  60 . Alternatively, as shown in  FIG. 6B , the bore  62  may be aligned with the second bore  64  along the central axial plane. The location of the second bore  64  relative to the central axial plane of the dual crossover  60  is determined based on an angle at which the second lateral bore  28  is located relative to the main bore  22 . Therefore, configurations other than those shown in  FIGS. 6A and 6B  are possible. 
         [0029]    Referring again to  FIG. 4 , the first pipe assembly  66  and the second pipe assembly  68  extend in a downhole direction. The first pipe assembly  66  includes a first seal  72  coupled to a distal end of a first pipe  70  and the second pipe assembly  68  includes a second seal  76  coupled to a distal end of a second pipe  74 . The second pipe  74  is longer than the first pipe  70  and the second seal  76  includes a larger outer diameter than the first seal  72 . The difference in length between the first pipe  70  and the second pipe  74  is determined based on the difference between a landing depth of the first PBR  40  and the second PBR  50 . The sizes of the outer diameters of the first seal  72  and second seal  76  are determined based on the size of the opening  55  through the hollow deflector  52 . The second seal  76  is sized to restrict movement of the second seal  76  through the opening  55 . In another embodiment, the opening  55  is centrally located relative to the deflecting surface  54 . 
         [0030]    Referring now to  FIG. 7 , as the hydraulic set liner hanger assembly  56  is advanced through the main bore  22 , a downhole end of the second pipe assembly  68  abuts the deflecting surface  54  of the hollow diverter  52  that is located in the main bore  22 . The deflecting surface  54  directs the second pipe assembly  68  into the second lateral bore  28  and the second seal  76  is received in the second PBR  50  to provide a seal between the second liner  32  and the second pipe  74 . A protective sleeve (not shown) covering the second seal  76  shears off allowing the second seal  76  to move into the PBR  50 . Also as the hydraulic set liner hanger assembly  56  advances, the first seal  72  passes through the opening  55  of the hollow diverter  52  and is received in a PBR (not shown) in the pipe  44  to provide a seal between the first liner  26  and the first pipe  70 . The hydraulic set liner hanger  58  is then hydraulically set against the casing  24  in the main bore  22 . 
         [0031]    As shown in  FIG. 7 , the multilateral well is completed with a level 3 junction between the first and second lateral bores  26  and  28 , respectively, and the main bore  22 . Inflow control devices (ICDs) are included in order to equalize pressure across the first seal  72  and second seal  76 , which provides sand control. The junction may alternatively be a level 5 junction. The level 3 junction may be changed to a level 5 junction by replacing the seals  72 ,  76  with elastomeric seals and removing the ICDs. 
         [0032]    The completed multilateral well may now be used to circulate steam or another fluid through the lateral bores  26 ,  28 , to pre-heat the formation around the well or may be used as an injector well or as a producer well in a SAGD process, for example. Referring to  FIG. 8 , in order to use the completed multilateral well as a circulation well, an injector well or as a producer well, a first tubing  78  is received in the first liner  30 . The first tubing  78  provides communication between the first lateral bore  26  and the surface. A second tubing  80  is received in the second liner  32  to provide communication between the second lateral bore  28  and the surface. When the completed multilateral well is used as a circulation well in preparation for production or as an injector well, steam is delivered downhole through the first tubing  78  and the second tubing  80  to the first liner  30  and second liner  32 , respectively. For a circulation well, steam returns flow from the first liner  30  to the surface through an annular gap  82  located between the first tubing  78  and the first pipe  70  and from the second liner  32  to the surface through an annular gap  84  located between the second tubing  80  and the second pipe  74 . When the completed well is used as a producer well, a pump is installed in the main bore  22  to pump fluids from the lateral bores  26 ,  28  through the first tubing  78  and the second tubing  80  to the surface. 
         [0033]    Referring to  FIGS. 8 and 9 , installation of the first tubing  78  and second tubing  80  is achieved by feeding the second tubing  80  downhole first, followed by the first tubing  78 . Because the second bore  64  of the dual crossover  60  is located at a lower depth than the first bore  62  thereof, the second tubing  80  enters the second bore  64  as the second tubing  80  is fed into the main bore  22  due to the force of gravity acting on the second tubing  80 . The second tubing  80  is then fed through the second pipe  74 , which directs the second tubing  80  into the second liner  32 . Once the second tubing  80  has entered the dual crossover  60 , the first tubing  78  is fed into the main bore  22 . Because the second tubing  80  is received in the second bore  64 , the first tubing  78  is directed into the first bore  62  as the first tubing  78  moves downhole. The first tubing  78  is then fed through the first pipe  70 , which directs the first tubing  78  into the first liner  30 . Connections to a source of steam or a pump may then be performed. The first tubing  78  may be deployed after the second tubing  80  has entered the dual crossover  60  or after the second tubing  80  has landed in the second liner  32 . 
         [0034]    In vertical lateral wells in which gravity may not be used to locate the second bore first, the tubing  78 ,  80  may instead be selective, as will be understood by a person skilled in the art. 
         [0035]    In addition to facilitating deployment of tubing through the completed multilateral well, measurement equipment may be deployed quickly and accurately into the first and second liners  30 ,  32 . For example, a first distributed temperature sensing (DTS) system line  86  may be deployed into the first liner  30  and a second distributed temperature sensing (DTS) system line  88  may be deployed into the and second liner  32  in a similar manner as has been described for the first and second tubing  78 ,  80 . The DTS  86  and DTS  88  may be landed directly into the first and second liners  30 ,  32 , respectively, or, alternatively, may be landed into the first tubing  78  and second tubing  80 . Other types of measurement systems may also be deployed downhole including bubble tubes, temperature sensors and pressure sensors, for example. 
         [0036]    The first liner  30  and the second liner  32  may be slotted liners, screens or other sand control device, for example. The first liner  30  and second liner  32  may be the same type of liner or, alternatively, may be different types of liners. In an embodiment, the first and second pipes  78 ,  80  are 101 mm outer diameter pipes. As will be understood by a person skilled in the art, other sizes are possible. In addition, either or both of the first liner  30  and second liner  32  may have flow regulation devices associated therewith. For example, the first liner  30  and second liner  32  may incorporate inflow control devices (ICDs), steam splitters, or other types of flow control technology. 
         [0037]    Referring now to  FIG. 10 , a third lateral bore  90  has been drilled in the multilateral completed well of  FIG. 8 . The well  20  of  FIG. 10  includes three lateral branches and is shown in a partially completed state. In this embodiment, the third lateral bore  90  includes a third liner  92 . 
         [0038]    In this embodiment, the inlet pipe string  65  is not coupled to the dual crossover  60 . Instead, the dual crossover  60  is coupled by threading, for example, to a downhole end of a liner hanger  61  that is fitted with a tie back receptacle on the uphole portion thereof. The liner hanger  61  receives a seal assembly  94  located at a downhole end of a pipe  96  that is coupled to a downhole end of a second whipstock packer  98 . The second whipstock packer  98  includes a sealing element  100  and slips  102  to fix the second whipstock packer  98  in the main bore  22 . A second hollow diverter part  104  is received in an uphole end of the second whipstock packer  98 . A whipstock (not shown) is supported by the second whipstock packer  98  and oriented to direct milling and drilling tools to drill the third lateral bore  90 . The third liner  92  is run into the third lateral bore  90  along with a setting collar  106  including a third polished bore receptacle (PBR)  108 . A landing depth of the third PBR  108  is recorded for use later in the completion operation. The whipstock (not shown) is removed from the main bore  22  following the milling, drilling and liner setting operations for the third lateral bore  90 . 
         [0039]    A method of deploying a third pipe and a fourth pipe to form seals with the inlet portion  63  of the dual crossover  60  and the third liner  92  of the third lateral bore  90  in a single operation will now be described with reference to  FIGS. 10 and 11 . 
         [0040]    First, a second hollow deflector  110  is run down the main bore  22  and coupled to the second whipstock packer  98  in a similar manner as described for the second lateral completion. A second hydraulic set liner hanger assembly  112  is then introduced into the main bore  22 . The second hydraulic set liner hanger assembly  112  is similar to the hydraulic set liner hanger assembly  56  and, therefore, will not be repeated here. An inlet pipe string  126  is coupled to an inlet portion of the dual crossover and a third pipe assembly  114  and a fourth pipe assembly  116  extend in a downhole direction. The third pipe assembly  114  includes a third seal  118  coupled to a distal end of a third pipe  120  and the fourth pipe assembly  116  includes a fourth seal  122  coupled to a distal end of a fourth pipe  124 . The fourth pipe  124  is longer than the third pipe  120  and the fourth seal  122  includes a larger outer diameter than the third seal  118 . The difference in length between the third pipe  120  and the fourth pipe  124  is determined based on the difference between a landing depth of the third PBR  108  and a PBR (not shown) in the dual crossover  60 . The sizes of the outer diameters of the third seal  118  and the fourth seal  122  are determined based on the size of the opening through the second hollow deflector  110 , as has been described with respect to the hydraulic set liner hanger assembly  56 . 
         [0041]    Referring now to  FIG. 11 , as the second hydraulic set liner hanger assembly  112  is advanced through the main bore  22 , a downhole end of the fourth pipe assembly  114  is deflected by the second hollow diverter  110  into the third lateral bore  90  and the fourth seal  122  is received in the third PBR  108  to provide a seal between the third liner  92  and the fourth pipe  124  in a similar manner as described with respect to the second lateral bore  281 . Also as the second hydraulic set liner hanger assembly  112  advances, the third seal  118  passes through the second hollow diverter  110  and is received in a PBR (not shown) in the dual crossover  60  to provide a seal between the hydraulic set liner hanger assembly  56  and the third pipe  120 . The second hydraulic set liner hanger assembly  112  is then set in the main bore  22 . 
         [0042]    Tubing may then be deployed to the first, second and third lateral bores  26 ,  28  and  90  of the completed multilateral well, as has been described. Measurement equipment may also be deployed as has been described. 
         [0043]    It will be understood by a person skilled in the art that the method and apparatus described herein is not limited to multilateral wells having two or three lateral bores. The method and apparatus described herein may be used to complete multilateral wells having four or more lateral bores. As will be understood by a person skilled in the art, the maximum number of lateral bores of a multilateral well may be determined by the diameter of the main bore  22 , diameters of the pipe assemblies  66 ,  68 ,  114 ,  116 , for example. 
         [0044]    The description above does not include details relating to orientation equipment such as gyros and universal bottom hole orienting sub (UBHO) equipment. It will be understood by a person skilled in the art that this equipment along with alignment to scribe lines and other orientation procedures are performed in order to ensure that equipment is correctly placed during the completion method. In addition, many components include mule shoes to facilitate direction of the components into position. Such components are known in the art and will not be described in detail herein. 
         [0045]    An advantage of the method and apparatus described herein is that two or more wells may be drilled from one surface location and well bore completion steps may be performed in a single operation. This results in significant time, and therefore, cost savings, which may amount to 25% or more. In addition, measurement equipment may be run into each one of the lateral bores in a single step. This provides additional downhole information and saves deployment time to achieve the additional information. 
         [0046]    The above-described embodiments are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art without departing from the scope of the present application, which is defined solely by the claims appended hereto.