Patent Publication Number: US-2005121190-A1

Title: Segregated deployment of downhole valves for monitoring and control of multilateral wells

Description:
BACKGROUND  
      The present invention relates generally to operations performed and equipment utilized in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides a well completion, system and method for controlling and monitoring fluid flow in multilateral wells.  
      It is typical practice when controlling and/or monitoring production flow from a lateral or branch wellbore, and from a portion of a main or parent wellbore below an intersection between the main and branch wellbores, to use one or more flow control devices and/or sensors positioned in the main wellbore. Unfortunately, this means that a flow control device/sensor used to control/monitor production from the branch wellbore may be positioned a relatively large distance from a zone in which the production originates.  
      Even a flow control device/sensor used to control/monitor production from a lower portion of the main wellbore may be positioned a relatively large distance from a zone in which the production originates, for example, when the flow control device/sensor is positioned above an intersection between the main and branch wellbores. Flow between a wellbore and a zone intersected by the wellbore is more conveniently and accurately monitored and controlled when a device used to monitor/control such flow is positioned in the wellbore in closer proximity to the zone.  
      Lines, such as hydraulic, electric, fiber optic, etc. lines, which are used to remotely operate and communicate with the flow control devices and sensors may be attached to a tubing string on which the flow control devices and sensors are conveyed into a well. If flow control devices and sensors are to be positioned in branch wellbores as well as in the main wellbore, there exists a need to conveniently and reliably provide for the lines extending into the branch wellbore(s), without requiring interruptions (breaks or disconnections) in the lines or requiring lines to be “wet” connected while downhole.  
      Therefore, it will be readily appreciated that there exists a need for improved well completions, systems and methods to address these problems and/or other problems in the art of completing multilateral wells. These improvements will also be useful in other applications.  
     SUMMARY  
      In carrying out the principles of the present invention, in accordance with an embodiment thereof, a well completion, completion system and method are provided which alleviate the above problems in the art.  
      In one aspect of the invention, a well completion system is provided. The well completion system includes at least one line extending to a remote location and into at least first and second intersecting wellbores. The line is positioned in the first and second wellbores without making a connection in the line downhole.  
      In another aspect of the invention, a well completion system includes two or more tubular strings. One of the tubular strings extends in a wellbore, and another tubular string extends in another wellbore intersecting the first wellbore. Lines are attached to the tubular strings. At least one of the lines extends with the first tubular string in the first wellbore, and at least one of the lines extends with the other tubular string in the other wellbore.  
      In yet another aspect of the invention, a method of completing a well including intersecting wellbores is provided. The method includes the steps of: conveying at least one line into each of the wellbores; and performing the conveying step without making any connections in the line in the well.  
      These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the invention hereinbelow and the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a partially cross-sectional schematic view of an initial configuration of a well completion system embodying principles of the present invention;  
       FIG. 2  is a partially cross-sectional view of a final configuration of the well completion system of  FIG. 1 ;  
       FIG. 3  is a partially cross-sectional schematic view of an initial configuration of another well completion system embodying principles of the present invention;  
       FIG. 4  is a partially cross-sectional view of a final configuration of the well completion system of  FIG. 3 ;  
       FIG. 5  is a schematic partially cross-sectional view of a third well completion system embodying principles of the invention; and  
       FIG. 6  is a schematic partially cross-sectional view of a fourth well completion system embodying principles of the invention. 
    
    
     DETAILED DESCRIPTION  
      Representatively illustrated in  FIG. 1  is a multilateral well completion system  10  which embodies principles of the present invention. In the following description of the system  10  and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention.  
      As depicted in  FIG. 1 , a tubular string  12 , such as a production tubing string, is being used to convey two other tubular strings  14 ,  16  into a parent or main wellbore  18 , The main wellbore  18  may be lined with protective casing or liner  20 , or any portion of the wellbore may be completed open hole, if desired.  
      Another branch or lateral wellbore  22  intersects the main wellbore  18  at an intersection  24 . The branch wellbore  22  may be lined with a liner  26 , or any portion of the branch wellbore may be completed open hole, if desired.  
      A whipstock or deflector  28  is positioned in the main wellbore  18  adjacent and just below the intersection  24 . As used herein, the term “below” means relatively farther along a wellbore from the earth&#39;s surface. Conversely, the term “above” means relatively closer to the earth&#39;s surface along a wellbore. Thus, the terms “above” and “below” may accurately describe a relative position in a wellbore, even if the wellbore is horizontal.  
      The deflector  28  may have been used to drill the branch wellbore  22 , or it may have been positioned in the main wellbore  18  after drilling the branch wellbore. The deflector  28  includes a bore  30  extending longitudinally therethrough. An upper inclined surface  32  of the deflector  28  is oriented so that it faces toward the branch wellbore  22 .  
      An assembly  34  is positioned in the main wellbore  18  below the deflector  28 , and a similar assembly  36  is positioned in the branch wellbore  22 . Each of the assemblies  34 ,  36  includes a seal bore  38  attached to, or otherwise associated with, a sealing and anchoring device  40 , such as a packer or liner hanger, etc.  
      Each of the tubular strings  14 ,  16  includes a sealing device  42 , such as seals, packing, etc., for sealing engagement in a respective one of the seal bores  38 . Alternatively, the sealing device  42  on the tubular string  16  could sealingly engage the bore  30  of the deflector  28 . Any manner or location of sealing engagement between the tubular strings  14 ,  16  and the wellbores  18 ,  22  may be used, in keeping with the principles of the invention.  
      Also included in each of the tubular strings  14 ,  16  is a flow control device  44 , such as a valve or choke, etc., and a sensor  58 . Preferably, the flow control devices  44  are remotely controlled, for example, via one or more lines  46  extending to a remote location, such as the earth&#39;s surface or another position in the well. The sensors  58  also communicate with the remote location via the lines  46 .  
      The lines  46  may be hydraulic, electric, fiber optic, or another type of line. Alternatively, or in addition, the flow control devices  44  and/or sensors  58  may be controlled and/or monitored remotely via telemetry without use of the lines  46 . For example, the flow control devices  44  and sensors  58  could be controlled and/or monitored remotely using acoustic, pressure pulse, electromagnetic, or any other type of telemetry.  
      The flow control devices  44  may be Interval Control Valves commercially available from WellDynamics, Inc. of Spring, Tex. These Interval Control Valves not only control flow between a tubular string and a zone intersected by a wellbore, they may also include the ability to monitor certain well parameters. For example, an optical fiber in one of the lines  46  connected to the flow control devices  44  may be used in distributed temperature sensing.  
      If desired, the relative longitudinal positions of the flow control devices  44  and sealing devices  42  as depicted in  FIG. 1  may be reversed in the tubular strings  14 ,  16 , since the Interval Control Valves are designed to regulate flow laterally through their sidewalls, rather than between upper and lower ends thereof. The flow control devices  44  may control flow through a longitudinal passage formed through each device, or through a sidewall of each device, in keeping with the principles of the invention.  
      The sensors  58  may include pressure, temperature, flow rate, resistivity, fluid identification, water cut, or any other type of sensors. As with the flow control devices  44 , the relative position of the sensors  58  in the tubular strings  14 ,  16  may be changed, if desired. The sensors  58  may be positioned internal or external to the tubular strings  14 ,  16 , and may detect properties of substances internal or external to the tubular strings.  
      A junction  48  is provided between the tubular strings  12 ,  14 ,  16 . Via the junction  48 , each of the tubular strings  12 ,  14 ,  16  is in communication with each of the other tubular strings. This is similar in many respects to the Isolated Tie-Back System commercially available from Halliburton Energy Services, Inc. of Houston, Tex. However, it should be clearly understood that such communication between the tubular strings  12 ,  14 ,  16  is not necessary in keeping with the principles of the invention.  
      The tubular string  14  includes a bull nose  50  at a lower end thereof, in order to deflect the tubular string into the branch wellbore  22 . That is, the deflector  28  is configured so that it is selective, deflecting the tubular string  14  off of the surface  32  into the branch wellbore  22 , but permitting the tubular string  16  to pass through the bore  30  and into a lower portion  52  of the main wellbore  18 . For example, the bull nose  50  may have a larger outer diameter than an inner diameter of the bore  30 , the bull nose may be shaped in a manner otherwise preventing it from passing into the bore, etc.  
      Alternatively, the tubular string  16  could be longer than the tubular string  14 , so that the tubular string  16  enters the bore  30  first. Then, as the tubular string  12  is lowered further, the presence of the tubular string  16  in the bore  30  prevents the tubular string  14  from entering the bore, and so the tubular string  14  is deflected by the surface  32  into the branch wellbore  22 . An illustration of this alternative is provided in  FIGS. 3 &amp; 4 , and is described in further detail below.  
      Referring additionally now to  FIG. 2 , the system  10  is representatively illustrated in a configuration in which the tubular string  14  has been deflected into the branch wellbore  22 , and the tubular string  16  has passed through the bore  30  into the lower portion  52  of the main wellbore  18 . The sealing devices  42  on the tubular strings  14 ,  16  have sealingly engaged the respective bores  38  of the assemblies  36  in the branch wellbore  22  and in the lower portion  52  of the main wellbore  18 . Alternatively, the sealing devices  42  could sealingly engage other structures in the wellbores  18 ,  22 , for example, the sealing devices could be packers or liner hangers which sealingly engage the casing  18  and liner  26 , without use of the assemblies  34 ,  36 .  
      The flow control devices  44  on the tubular strings  14 ,  16  may now be used to control fluid flow between the respective tubular string and the branch wellbore  22  or the lower portion  52  of the main wellbore  18 . The flow control device  44  on the tubular string  14  may now be used to control flow (production or injection) between the tubular string and a formation or zone  54  intersected by the branch wellbore  22 , and the flow control device on the tubular string  16  may now be used to control flow (production or injection) between the tubular string  16  and a formation or zone  56  intersected by the lower portion  52  of the main wellbore  18 . Note that the zones  54 ,  56  may be separate portions of the same zone or formation, and one of the tubular strings  14 ,  16  may be used for injection while the other is used for production, etc.  
      Note that the flow control devices  44  are positioned in close proximity to the respective zones  54 ,  56 , enhancing the proper and accurate operation of the flow control devices to achieve a desired rate or quantity of flow therethrough. Monitoring parameters of the well completion using the sensors  58  is also performed in close proximity to the zones  54 ,  56 , thereby enhancing the accuracy of these measurements. The ability to remotely control the flow control devices  44  and monitor the sensors  58  via the lines  46 , coupled with the enhanced accuracy provided by the positioning of the flow control devices and sensors, permits precise control and monitoring of production and/or injection operations in the well.  
      Furthermore, note that the lines  46  attached to the tubular strings  12 ,  14 ,  16  are installed in a manner that does not require interruptions in the lines and does not require any “wet” connections between lines while downhole. Instead, the lines  46  continue to be operably connected to the flow control devices  44  and sensors  58 , and extend unbroken to the remote location, during the installation of the tubular strings.  
      Referring additionally now to  FIG. 3 , another multilateral well completion system  60  is representatively illustrated. The system  60  is similar in many respects to the system  10  described above, and so elements of the system  60  which are similar to elements of the system  10  described above are indicated in  FIG. 3  using the same reference numbers.  
      As depicted in  FIG. 3 , the tubular strings  12 ,  14 ,  16  are being conveyed into the main or parent wellbore  18 , similar to the system  10  as shown in  FIG. 1 . However, another branch wellbore  62  intersects the main wellbore  18  at an intersection  64 . A deflector  66  has been positioned just below the intersection  64 , and has been oriented so that an upper inclined deflection surface  68  faces toward the branch wellbore  62 .  
      The deflector  66  has a bore  70  extending therethrough which is large enough for the tubular strings  14 ,  16  to pass through side-by-side. Thus, as the tubular strings  12 ,  14 ,  16  are further lowered in the main wellbore  18 , the tubular strings  14 ,  16  will both enter the bore  70  and pass through the deflector  66 .  
      Referring additionally now to  FIG. 4 , the system  60  is depicted in a configuration in which the tubular strings  14 ,  16  have passed through the deflector  66 . Further conveyance of the tubular strings  12 ,  14 ,  16  into the main wellbore  18  causes the tubular string  14  to deflect off of the deflector surface  32  and into the branch wellbore  22 , as described above for the system  10 . Still further conveyance of the tubular strings  12 ,  14 ,  16  into the main wellbore  18  causes the tubular string  16  to enter the bore  30  of the deflector  28 , also as described above for the system  10 .  
      Another tubular string  72  is connected to the tubular string  12  by means of another junction  48 . The tubular string  72  is similar to the tubular string  14 , in that it includes a sealing device  42 , a flow control device  44  and a sensor  58 . The lines  46  extend to the flow control device  44  and sensor  58  on the tubular string  72 .  
      The junction  48  provides communication between the tubular strings  12 ,  72  and another tubular string  74  connected thereabove and extending to a remote location. The tubular string  74  is, thus, used to convey the other tubular strings  12 ,  14 ,  16 ,  72  into the main wellbore  18 .  
      As the tubular string  74  conveys the other tubular strings  12 ,  14 ,  16 ,  72  into the main wellbore  18 , the tubular strings  14 ,  16  pass through the deflector  66 , as described above. The tubular string  12  also enters the bore  70  of the deflector  66  after the lower junction  48  enters the bore  70 . Thus, when the lower end of the tubular string  72  reaches the deflector  66 , the tubular string  12  is already in the bore  70 .  
      The tubular string  72  includes a bull plug  76  or other device at its lower end which prevents the tubular string  72  from entering the bore  70  while the tubular string  12  is in the bore. For example, the bull plug  76  may be sized or otherwise configured so that it cannot fit into the bore  70  while the tubular string  12  is in the bore. Instead, the tubular string  72  is deflected by the surface  68  into the branch wellbore  62 .  
      The tubular string  72  may be deflected into the branch wellbore  62  at about the same time as the tubular string  14  is deflected into the branch wellbore  22 . Of course, depending upon the relative lengths of the tubular strings  12 ,  14 ,  16 ,  72  and relative positions of the deflectors  28 ,  66 , the tubular string  72  may be deflected into the branch wellbore  62  before or after the tubular string  14  is deflected into the branch wellbore  22 .  
      With the tubular strings  12 ,  14 ,  16 ,  72 ,  74  positioned as depicted in  FIG. 4 , the sealing devices  42  are set or otherwise sealingly engaged in the respective wellbores  18 ,  22 ,  62 . Note that, as depicted in  FIG. 4 , the sealing device  42  on the tubular string  14  is sealingly engaged with the liner  26 , the sealing device  42  on the tubular string  16  is sealingly engaged in the bore  30 , the sealing device  42  on the tubular string  72  is sealingly engaged in a liner  78  in the branch wellbore  62 , and a sealing device  42  on the tubular string  12  is sealingly engaged in the bore  70 . Of course, the sealing devices  42  may be otherwise positioned in the wellbores  18 ,  22 ,  62 , and may be otherwise sealingly engaged in the wellbores, in keeping with the principles of the invention.  
      In a producing well, the flow control device  44  on the tubular string  14  can now control fluid flow from the zone  54 , the flow control device  44  on the tubular string  16  can now control flow from the zone  56 , and the flow control device  44  on the tubular string  72  can now control fluid flow from a formation or zone  80  intersected by the wellbore  62 . The sensors  58  can be used to monitor these respective fluid flows, or to detect other parameters in the well.  
      The lower junction  48  commingles the flows from the tubular strings  14 ,  16  into the tubular string  12 . The upper junction  48  commingles the flows from the tubular strings  12 ,  72  into the tubular string  74  for production to the surface. For an injection well, these flow directions may be reversed.  
      Note that, in the system  60 , the lines  46  are extended into multiple branch wellbores  22 ,  62 , while also extending in the main wellbore  18 . This positioning of the lines  46  is accomplished in the system  60  without interruptions in the lines and without requiring any “wet” connections between lines downhole. Instead, the lines  46  extend continuously from the sensors  58  and flow control devices  44  to the remote location. This enhances the reliability and performance of the lines  46 , while reducing the complexity of the completion operation.  
      In  FIG. 4 , the lines  46  extend through the sealing device  42  on the tubular string  12 . This configuration may be accomplished at the surface using “dry” connections (i.e., connections made between lines while at the surface) at upper and lower ends of the sealing device  42 , without compromising the reliability or performance of the lines when installed.  
      Although only two branch wellbores  22 ,  62  are depicted in  FIGS. 3 &amp; 4 , it will be readily appreciated that any increased number of branch wellbores may be provided for by increasing the number of tubular strings deflected into the respective branch wellbores, and increasing the number of deflectors, junctions, flow control devices, sensors, etc., as needed. The lines  46  can extend into any number of branch wellbores to any number of flow control devices, sensors, etc., without interruptions in the lines and without requiring any “wet” connections between lines downhole.  
      Referring additionally now to  FIG. 5 , another well completion system go is representatively illustrated. The system go is similar in many respects to the systems  10 ,  60  described above, and so elements of the system go which are similar to elements of the systems  10 ,  60  described above are indicated in  FIG. 5  using the same reference numbers.  
      As depicted in  FIG. 5 , a tubular string  92  is deflected off of the inclined surface  32  of the deflector  28  and into the branch wellbore  22 . The tubular string  92  is connected to another tubular string  94  via a junction or wye block  96 . The wye block  96  permits access to each of the tubular strings  92 ,  94 , and flow through each of the tubular strings is commingled in the wye block.  
      The tubular string  94  is sealingly engaged in the bore  30  of the deflector  28 . Attached below the deflector  28  is another tubular string  98  positioned in the lower portion  52  of the main wellbore  18 . The tubular string  98  is installed with the deflector  28  and anchoring device  40  prior to conveying the tubular strings  92 ,  94  into the well using the tubular string  12 .  
      The tubular string  98  has the flow control device  44 , lines  46  and sensor  58  interconnected therein when it is installed. In order to connect the lines  46  on the tubular string  98  to the lines  46  on the tubular string  94 , a “wet” connection  100  is made when the tubular string  94  is engaged with the deflector  28 . For example, one connector may be attached to the deflector  28  and operably coupled to the lines  46  on the tubular string  98 , while another connector may be attached to the tubular string  94  and operably coupled to the lines on the tubular string  94 . When the tubular string  94  is inserted into the bore  30 , the connectors mate to form the connection  100 .  
      Although the system go does include the “wet” connection  100 , it is positioned in the main wellbore  18  where it is more conveniently accessible in the event of a malfunction. Note that the lines  46  on the tubular string  92  extending into the branch wellbore  22  extend continuously from the flow control device  44  and sensor  58  to the remote location, without requiring any “wet” connections to be made downhole.  
      Referring additionally now to  FIG. 6 , another well completion system  110  is representatively illustrated. The system  110  is similar in many respects to the systems  10 ,  60 , go described above, and so elements of the system  110  which are similar to elements of the systems  10 ,  60 , go described above are indicated in  FIG. 6  using the same reference numbers.  
      As depicted in  FIG. 6 , a tubular string  112  is deflected off of the inclined surface  32  of the deflector  28  and into the branch wellbore  22 . The sealing device  42  carried on a lower end of the tubular string  112  sealingly engages the assembly  36  previously positioned in the branch wellbore  22 , for example, by sealingly engaging the anchoring device  40 .  
      An upper end of the tubular string  112  remains in the main wellbore  18  and is connected to a junction  114  secured in the main wellbore by an anchoring device  116 , such as a packer. The junction  114  has an inner passage  118  which provides fluid communication between the tubular string  112  and an annulus  120  formed between the tubular string  12  and the main wellbore  18  above the junction. An opening  122  in the tubular string  12  permits fluid communication between the annulus  120  and the interior of the tubular string.  
      Another tubular string  124  extends downwardly from the junction  114  and is sealingly engaged in the bore  30  of the deflector  28 . Similar to the system  90  depicted in  FIG. 5 , the tubular string  98  is connected below the deflector  28  and is installed in the main wellbore  18  prior to running the junction  114  and tubular strings  112 ,  124  into the well. The “wet” connection  100  is made between the lines  46  connected to the tubular string  98  and the lines connected to the tubular string  124  when the tubular string  124  engages the deflector  28 .  
      The tubular string  124  is in fluid communication with another passage  126  formed through the junction  114 . The passage  126  is, in turn, in fluid communication with the tubular string  12 . Thus, fluids from the tubular strings  124 ,  112  are commingled in the tubular string  12 . The tubular string  12  is sealingly engaged with the junction  114  by means of seals  128  carried on the tubular string, which are inserted into the passage  126 , or into a seal bore at an upper end of the passage.  
      When the tubular string  12  engages the junction  114 , another “wet” connection  100  is formed between the lines  46  attached to the tubular string  12  and the lines  46  attached to the junction  114 . As with the connection  100  between the lines  46  attached to the tubular string  124  and the lines  46  attached to the deflector  28 , the connection between the lines  46  attached to the tubular string  12  and the lines  46  attached to the junction  114  is made in the main wellbore  18  where it is most conveniently accessible in case of a malfunction.  
      Note that the lines  46  extending into the branch wellbore  22  do not require a “wet” connection in the branch wellbore or at the intersection  24 . Furthermore, it is not necessary for the connection  100  between the lines  46  attached to the tubular string  12  and the lines  46  attached to the junction  114  to be made in the wellbore  18 , since the junction  114  and the tubular strings  112 ,  124  could be conveyed together into the well, instead of installing the junction and tubular strings  112 ,  124  in the well prior to running in the tubular string  12 .  
      One advantage to using the junction  114  is that it includes another passage  130  which provides access from the passage  126  to the passage  118  when a sleeve  132  is retrieved from, or shifted in, the junction. As depicted in  FIG. 6 , access to the lower main wellbore  52  is available via the tubular string  12 , the passage  126 , the tubular string  124  and the tubular string  98 . Access to the branch wellbore  22  may be obtained by retrieving or shifting the sleeve  132  and installing a deflector (not shown) in the passage  126  to deflect tools, equipment, etc. from the passage  126 , through the passage  130  into the passage  118 , and then through the tubular string  112 .  
      Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are contemplated by the principles of the present invention. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents.