Abstract:
A gravel pack completion with fiber optic monitoring. In a described embodiment, a method for completing a subterranean well includes the steps of: positioning at least one assembly in a wellbore of the well; then inserting a portion of a tubular string into the assembly; and attaching a fiber optic line to the tubular string portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application is related to the following copending applications filed concurrently herewith: attorney docket no. 009328 U1 USA, entitled DOWNHOLE FIBER OPTIC WET CONNECT AND GRAVEL PACK COMPLETION; and attorney docket no. 009526 U1 USA, entitled GRAVEL PACK COMPLETION WITH FLUID LOSS CONTROL AND FIBER OPTIC WET CONNECT. The entire disclosures of these related applications are incorporated herein by this reference.  
     
    
     BACKGROUND  
       [0002]     The present invention relates generally to equipment utilized and operations performed in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides a gravel pack completion with fiber optic monitoring.  
         [0003]     It would be very desirable to be able to use a fiber optic line to monitor production from a well, for example, to monitor water encroachment, identify production sources, evaluate stimulation treatments, gravel packing effectiveness and completion practices, etc. It is known to use fiber optic lines to transmit indications from downhole sensors, to communicate in the downhole environment and to use a fiber optic line as a sensor.  
         [0004]     However, fiber optic lines may be damaged in operations such as gravel packing, expanding tubulars downhole, etc. For this reason, it would be beneficial to be able to install a fiber optic line in a completion, for example, after a completion assembly has been installed in a well and gravel packing operations are completed, or after an assembly has been expanded, etc.  
         [0005]     Furthermore, it is sometimes desirable to complete a well in sections or intervals, for example, where a horizontal well is gravel packed in sections, or where zones intersected by a vertical well are separately gravel packed. In these cases, it would be beneficial to be able to conveniently install a fiber optic line in each of the gravel packed sections.  
       SUMMARY  
       [0006]     In carrying out the principles of the present invention, in accordance with described embodiments thereof, systems and methods are provided which permit a fiber optic line to be conveniently installed in an assembly previously installed in a well.  
         [0007]     In one aspect of the invention, a method for completing a subterranean well is provided. The method includes the steps of: positioning at least one assembly in a wellbore of the well; then inserting a portion of a tubular string into the assembly; and attaching a fiber optic line to the tubular string portion.  
         [0008]     In another aspect of the invention, a system for completing a subterranean well is provided. The system includes an assembly positioned in a wellbore of the well. A portion of a tubular string is inserted into the assembly after the assembly is positioned in the wellbore. A fiber optic line is attached to the tubular string portion.  
         [0009]     In yet another aspect of the invention, a system for completing a subterranean well includes at least first and second assemblies positioned in a wellbore of the well. A tubular string has a portion thereof inserted into both of the first and second assemblies after the first and second assemblies are positioned in the wellbore. A fiber optic line is attached to the tubular string portion.  
         [0010]     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  
       [0011]      FIG. 1  is a schematic cross-sectional view of a system and method embodying principles of the present invention, in which initial steps of the method have been performed;  
         [0012]      FIG. 2  is a schematic cross-sectional view of the system and method of  FIG. 1 , in which further steps of the method have been performed;  
         [0013]      FIG. 3  is a schematic cross-sectional view of another system and method embodying principles of the present invention, in which initial steps of the method have been performed;  
         [0014]      FIG. 4  is a schematic cross-sectional view of the system and method of  FIG. 3 , in which further steps of the method have been performed; and  
         [0015]      FIG. 5  is an enlarged partially cross-sectional view of a system and method of installing a fiber optic line in the systems and methods of  FIGS. 1 &amp; 3 .  
     
    
     DETAILED DESCRIPTION  
       [0016]     Representatively illustrated in  FIG. 1  is a system and method  10  which embodies principles of the present invention. In the following description of the system and method  10  and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used only 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.  
         [0017]     As depicted in  FIG. 1 , a gravel packing assembly  12  has been positioned in a wellbore  14 . Representatively, a gravel pack packer  16  of the assembly  12  is set in a cased portion of the wellbore  14 , and a well screen  18  of the assembly is positioned in an uncased portion of the wellbore. However, it should be clearly understood that any or all of the gravel packing assembly  12  may be positioned in either a cased or an uncased wellbore or wellbore portion.  
         [0018]     Gravel  20  is flowed into an annulus formed between the screen  18  and the wellbore  14 . Fluid in a formation or zone  22  intersected by the wellbore  14  can flow through the gravel  20 , through the screen  18  and into an internal flow passage  24  of the assembly  12 . A conventional gravel packing service tool (not shown) may be used to flow the gravel  20  into the annulus between the screen  18  and the wellbore  12 , in a manner well known to those skilled in the art.  
         [0019]     When the service tool is removed from the assembly  12 , a fluid loss control device  26  of the assembly prevents fluid in the wellbore  14  above the assembly from flowing into the formation  22  via the passage  24 . The fluid loss control device  26  may be a Model FSO device available from Halliburton Energy Services of Houston, Tex., in which case the device may prevent flow therethrough in each direction when closed.  
         [0020]     As depicted in  FIG. 1 , the fluid loss control device  26  is closed (preventing flow into the formation  22 ), but the fluid loss control device may be configured to permit upward flow through the passage  24 , in the manner of a check valve, if desired. When open, the fluid loss control device  26  permits fluid flow from the passage  24  into the formation  22 .  
         [0021]     Note that the fluid loss control device  26  may be configured other than as shown in  FIG. 1 . For example, the fluid loss control device  26  may be incorporated into the screen  18 , in which case the device may permit inward flow through the screen between the formation  22  and the passage  24 , while preventing outward flow through the screen between the passage and the formation, in the manner of a check valve. If incorporated into the screen  18 , the device  26  may be unaffected by the retrieval of the service tool from the assembly  12 .  
         [0022]     Referring additionally now to  FIG. 2 , a tubular string  28 , such as a production tubing string, is installed in the wellbore  14 . The tubular string  28  includes a packer  30  and a sealing device  32 , such as a packing stack or a seal assembly. The packer  30  is set to sealingly secure the tubular string  28  in the wellbore  14 .  
         [0023]     A lower portion  34  of the tubular string  28  extends into the passage  24  of the assembly  12 , and the sealing device  32  sealingly engages a seal bore  36 , such as a polished bore receptacle, associated with the packer  16 . Preferably, the tubular string portion  34  is perforated to permit or enhance flow into the tubular string  28  from the passage  24 .  
         [0024]     When the lower portion  34  is inserted into the assembly  12 , the fluid loss control device  26  may open, permitting flow therethrough in each direction. However, it should be understood that the fluid loss control device  26  may be opened before, during or after the lower portion  34  is inserted into the assembly  12 . Of course, if the fluid loss control device  26  is incorporated into the screen  18 , insertion of the portion  34  into the assembly  12  may not affect operation of the fluid loss control device.  
         [0025]     Attached to the tubular string  28  is a fiber optic line  38 . The fiber optic line  38  may, for example, be encased in a cable, or it may be in a conduit as described in further detail below. Any means of attaching the fiber optic line  38  to the tubular string  28  may be used, in keeping with the principles of the invention.  
         [0026]     The fiber optic line  38  extends longitudinally through the packer  30 , and also extends longitudinally through the sealing device  32 . If the fiber optic line  38  is contained in a conduit, portions of the conduit may be formed in the packer  30  and sealing device  32 , and then the fiber optic line may be passed through the conduit in these elements before, during or after the tubular string  28  is run into the wellbore  14 .  
         [0027]     Note that the fiber optic line  38  extends longitudinally in the passage  24  within the screen  18 . In this manner, the fiber optic line  38  may be used to monitor well parameters, such as temperature, pressure, flow rate, water cut, fluid identification, etc. For this purpose, the fiber optic line  38  may have appropriate sensors connected thereto and/or the fiber optic line may itself serve as a sensor, for example, using Bragg gratings on the fiber optic line.  
         [0028]     As depicted in  FIG. 2 , the fiber optic line  38  is attached to an exterior of the tubular string  28 . However, it should be understood that the fiber optic line  38 , or any portion of the fiber optic line, may be positioned internal or external to the tubular string  28  in keeping with the principles of the invention.  
         [0029]     It may now be fully appreciated that the system  10  permits the fiber optic line  38  to be conveniently installed in the assembly  12  after the gravel packing operation is completed. This helps to prevent damage to the fiber optic line  38 . Convenient installation of the fiber optic line  38  (or at least the conduit therefor) is provided by installing it along with the tubular string  28 , which would normally be run subsequent to the gravel packing operation.  
         [0030]     Referring additionally now to  FIG. 3 , another system and method  40  is representatively illustrated. In the system  40 , multiple gravel packing assemblies  42 ,  44  are installed in a wellbore  46 . Any number of gravel packing assemblies, or other types of well tool assemblies, may be installed in the wellbore  46  in keeping with the principles of the invention.  
         [0031]     As depicted in  FIG. 3 , the gravel packing assemblies  42 ,  44  may both be installed in cased portions of the wellbore  46 . However, it should be understood that all or any portion of the assemblies  42 ,  44  may be positioned in an uncased portion of the wellbore  46 .  
         [0032]     Preferably, the lower assembly  42  is installed first, a gravel pack packer  52  of the assembly is set in the wellbore  46 , and a gravel packing operation is performed to place gravel  48  between a screen  50  of the assembly and the wellbore. Fluid from a formation or zone  56  intersected by the wellbore  46  can now flow through the gravel  48 , inward through the screen  50  and into an interior flow passage  58  extending through the screen.  
         [0033]     When a service tool (not shown) is retrieved from the assembly  42  after the gravel packing operation, a fluid loss control device  54  of the assembly is closed. The fluid loss control device  54  may be similar to the fluid loss control device  26  described above, and the fluid loss control device may be incorporated into the screen  50 , in which case retrieval of the service tool may not affect operation of the device.  
         [0034]     The upper gravel packing assembly  44  is then installed in the wellbore  46 . The gravel packing assembly  44  is similar to the gravel packing assembly  42 , in that it includes a gravel pack packer  60 , a screen  62  and a fluid loss control device  64 . A sealing device  66  carried at a lower end of the assembly  44  sealingly engages a seal bore  68  associated with the packer  52 .  
         [0035]     When the upper assembly  44  engages the lower assembly  42 , the lower fluid loss control device  54  can be opened. This provides unimpeded communication between the passage  58  and another interior flow passage  70  formed longitudinally through the screen  62 . Thus, the flow passages  58 ,  70  at this point can form a continuous flow passage extending through the assemblies  42 ,  44 . Note that the fluid loss control device  54  may be opened before, during or after engagement between the assemblies  42 ,  44 .  
         [0036]     The packer  60  is set in the wellbore  46 , and a gravel packing operation is performed to place gravel  72  between the screen  62  and the wellbore. Fluid from a formation or zone  74  intersected by the wellbore  46  can now flow through the gravel  72 , inward through the screen  62  and into the flow passage  70 .  
         [0037]     When the gravel packing operation is completed and the service tool is retrieved from the assembly  44 , the fluid loss control device  64  is preferably closed to prevent fluid flow from the wellbore  46  above the assemblies  42 ,  44  into either of the formations  56 ,  74 . The fluid loss control device  64  may be similar to the fluid loss control device  26  described above, and the fluid loss control device may be incorporated into the screen  62 , in which case retrieval of the service tool may not affect operation of the device.  
         [0038]     Referring additionally now to  FIG. 4 , a tubular string  76 , such as a production tubing string, is installed in the wellbore  46  and engaged with the assemblies  42 ,  44 . A packer go of the tubular string  76  is set to sealingly secure the tubular string in the wellbore  46 .  
         [0039]     Engagement between the tubular string  76  and the upper assembly  44  may open the fluid loss control device  64 , permitting flow therethrough in each direction. The fluid loss control device  64  may be opened before, during or after engagement between the tubular string  76  and the upper assembly  44 . Of course, if the fluid loss control device  64  is incorporated in the screen  62 , such engagement may not affect operation of the device.  
         [0040]     A lowermost portion  78  of the tubular string  76  extends into the passage  58  of the lower assembly  42 , opening the fluid loss control device  54 , if not previously opened. Another portion  80  of the tubular string  76  extends through the passage  70  of the upper assembly  44 . Preferably, the portion  78  is perforated to enhance flow of fluid (indicated by arrows  82 ) into the tubular string  76  from the passage  58 , and the portion  80  is not perforated to exclude flow of fluid (indicated by arrows  84 ) from the formation  74  into the portion  80 .  
         [0041]     A sealing device  86  carried on the tubular string  76  between the portions  78 ,  80  engages a seal bore  88  at a lower end of the assembly  44  and isolates the passages  58 ,  70  from each other in the assemblies  42 ,  44 . Thus, the fluid  82  from the formation  56  flows inwardly through the screen  50 , into the passage  58 , and into the tubular string portion  78 , which communicates with an interior portion  92  of the tubular string  76  above the assemblies  42 ,  44 . Fluid  84  from the formation  74  flows inwardly through the screen  62 , into the passage  70 , and then into an annulus  94  formed between the tubular string  76  and the wellbore  46  above the assemblies  42 ,  44 .  
         [0042]     Flow between the annulus  94  and another interior portion  96  of the tubular string  76  is controlled by a remotely operable flow control device  98  interconnected in the tubular string. Flow between the lower interior tubular string portion  92  and the upper interior tubular string portion  96  is controlled by another remotely operable flow control device  100  interconnected in the tubular string. The flow control devices  98 ,  100  may be Interval Control Valves available from WellDynamics of Spring, Texas, or they may be any type of flow control devices, such as valves, chokes, etc.  
         [0043]     With both of the flow control devices  98 ,  100  partially or completely open, the fluids  82 ,  84  are commingled (indicated by arrow  102 ) in the upper interior tubular string portion  96 . The device  98  may be closed to prevent flow of the fluid  84  into the upper interior portion  96 , and the device  100  may be closed to prevent flow of the fluid  82  into the upper interior portion of the tubular string  76 . The devices  98 ,  100  may also be partially opened or closed (in the manner of a choke) to regulate the relative proportions of the fluid  102  contributed by each of the fluids  82 ,  84 .  
         [0044]     The flow control devices  98 ,  100  may be remotely operated by means of one or more hydraulic and/or electric lines or conduits  104  connected thereto, attached to the tubular string  76  and extending to a remote location, such as the earth&#39;s surface or another location in the well. In addition, a fiber optic line  106  is attached to the tubular string  76  and extends into the assemblies  42 ,  44 . The fiber optic line  106  may be installed in a conduit attached to the tubular string  76 , as described below.  
         [0045]     The fiber optic line  106  extends longitudinally from a remote location, through the packer  90 , through a telescoping travel joint  108  interconnected in the tubular string  76 , through the passage  70 , through the sealing device  86  and into the passage  58 . For monitoring well parameters in the passages  58 ,  70 , the fiber optic line  106  may have sensors connected thereto, or the fiber optic line may itself serve as a sensor, as described above.  
         [0046]     Referring additionally now to  FIG. 5 , a system and method  110  whereby a fiber optic line  112  may be installed in a conduit  114  attached to a tubular string  116  positioned in a well is representatively illustrated. The tubular string  116  is analogous to the tubular strings  28 ,  76  described above, and the fiber optic line  112  is analogous to the fiber optic lines  38 ,  106  described above.  
         [0047]     When initially installed in the well, the tubular string  116  has the conduit  114  attached thereto. The conduit  114  may be positioned internal or external to the tubular string  116 . The conduit  114  may extend through a sealing device  118 , such as a packer or a packing stack or seal assembly, etc., or through any other well tool interconnected in the tubular string  116 . The conduit  114  may be continuous, or it may be segmented, and portions of the conduit may be integrally formed in well tools, such as the device  118 , interconnected in the tubular string  116 .  
         [0048]     After the tubular string  116  is positioned in the well, the fiber optic line  112  is extended through the conduit  114 , for example, by pumping the fiber optic line through the conduit. A check valve  120  at a lower end of the conduit  114  permits fluid in the conduit to exit from the lower end of the conduit during the pumping operation. In this manner, the fiber optic line  112  is not subject to damage during installation of the tubular string  116  in the well.  
         [0049]     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.