Abstract:
A method of providing zonal isolation in a wellbore completion includes the steps of identifying an anticipated zone for isolation in a wellbore before completing the wellbore; selecting, before completing the wellbore, a completion assembly and a cooperative deployable isolation assembly to isolate the anticipated zone; completing the wellbore with the selected completion assembly; and connecting the selected deployable isolation assembly in the selected completion assembly to isolate the anticipated zone.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 60/688,843 filed on Jun. 9, 2005. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates in general to wellbore operations and more particular to a system for using a deployable isolation assembly to isolate selected zones in a wellbore. 
     BACKGROUND 
     Wellbores are often drilled through and completed for production and/or injection in multiple formations or zones of formations. Commonly, during the life of the wellbore it is desirable or necessary to isolate one or more of the zones. Prior systems isolation systems often require rigging up to isolate the desired zone. Additionally, often the prior art isolation systems result in a significant reduction in the flow path through the completed section of the well. 
     It is therefore a desire to provide a simple, easily deployable and stackable zonal isolation solution. 
     SUMMARY OF THE INVENTION 
     A deployable zonal isolation system and method for isolating zones in a wellbore is provided. In one embodiment, a method of providing zonal isolation in a wellbore completion includes the steps of identifying an anticipated zone for isolation in a wellbore before completing the wellbore; selecting, before completing the wellbore, a completion assembly and a cooperative deployable isolation assembly to isolate the anticipated zone(s); completing the wellbore with the selected completion assembly; and connecting the selected deployable isolation assembly in the selected completion assembly to isolate the anticipated zone. 
     The foregoing has outlined the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features and aspects of the present invention will be best understood with reference to the following detailed description of a specific embodiment of the invention, when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a schematic of a wellbore completed with an embodiment of the completion assembly of the present invention; 
         FIG. 2  is an exploded view of an embodiment of the deployable zonal isolation system; and 
         FIG. 3  is a perspective view of a wellbore completed with another embodiment of the isolation assembly of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views. 
     As used herein, the terms “up” and “down”; “upper” and “lower”; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements of the embodiments of the invention. Commonly, these terms relate to a reference point as the surface from which drilling operations are initiated as being the top point and the total depth of the well being the lowest point. 
       FIG. 1  is a schematic of a wellbore  12  completed with an embodiment of a selected completion assembly  14  of deployable zonal isolation system of the present invention, generally designated by the numeral  10 . In the illustrated embodiment, wellbore  12  is a gravel pack completion including casing  16 . As is well known in the art, gravel  18  is disposed in annulus  20  between casing  16  and completion assembly  14  by pumping a gravel  18  laden slurry through cross-over  22 . It should be noted that although the invention is illustrated with a cased gravel pack completion, the invention is applicable for open hole gravel packing and non-gravel packed completions. 
     Wellbore  12  is drilled into the earth having multiple formation zones  24  of interest. In  FIG. 1 , wellbore  12  includes a first zone  24   a  and a second zone  24   b  from which it is desired to produce hydrocarbons. In the present example, prior to the completion of wellbore  12  it is anticipated that during the production life of wellbore  12  that water will first encroach at zone  24   b  and will encroach later in time at zone  24   a . Thus, completion assembly  14  is selected and design for isolating zones  24   a  and  24   b  during the production life of the well. 
     Flow sections  28  are positioned within completion assembly  14  so as to be positioned adjacent the respective formation zones  24  upon completion of wellbore  12 . In anticipation of isolating flow sections  28 , one or more receivers  26  are incorporated into completion assembly  14 . As illustrated, a receiver  26   b  is positioned below flow section  28   b  and a receiver  26   a  is positioned between flow sections  28   a  and  28   b . Each of the receivers  26  is adapted to position an isolation assembly  30  ( FIG. 3 ) proximate a respective flow section  28  and flow zone  24 . As will be further understood with the following description, completion assembly  14  may include a single receiver  26  for isolating multiple flow sections  28  over the life of the well. 
       FIG. 2  is an illustration of deployable isolation system  10  including selected completion assembly  14  and deployable isolation assembly  30 . Completion assembly  14  is selected for a specific wellbore  12  and is adapted for accepting a cooperative deployable isolation assembly  30  to isolate a zone  24  during the production life of the well. 
     Flow sections  28  permit flow of fluid from the exterior of completion assembly  14  to its interior conduit  32 . Flow sections  28  may be constructed in many manners and/or comprise various apparatus. Examples of flow sections  28 , without limitation, include tubulars to be perforated at completion, pre-perforated tubulars, slotted liners and the various screen configurations. 
     Completion assembly  14  further includes one or more receivers  26 . Receivers  26  are adapted to position deployable isolation assembly  30  proximate to flow section  28  which is anticipated to be isolated. The distance between each receiver  26  and a respective flow section  28  is noted for the selected isolation assembly  30 . It is noted that completion assembly  14  may include other devices such as, but not limited to, valves and packers. 
     It should be noted that completion assembly  14  may comprise one elongated perforated tubular, wherein each flow section  28   a  and  28   b  is defined in relation to formation flow zones  24   a  or  24   b  or more specifically to portions of the formation that are expected to require isolation. As such, a single receiver  26  may be positioned for placement of a isolation assembly  30  in an isolation position of the lowest most flow section  28   b . Then, over the production life, subsequent isolation assemblies may be stacked with the first isolation assembly to progressively isolate zones as they water out. Further, receivers  26  may be placed proximate to one or more anticipated flow sections  28  for positioning isolation assemblies  30 . 
     Deployable isolation assembly  30  includes a mandrel  34  forming an internal bore  36  and a swellable material  38  disposed on its exterior. The length, diameter and other physical dimensions and properties of mandrel  34  and swellable material  38  are selected for positioning within interior  32  of selected completion assembly  14 . Isolation assembly  30  may be deployed via tubing, coiled tubing, slick line or wireline. 
     Isolation assembly  30  further includes a locating device  40  selected in combination with a receiver  26  in completion assembly  30 . As shown in  FIG. 2 , locating device  40  is a latching collet matable with latch profile  26  of completion assembly  14 . Other locating devices  40 , and cooperative receivers  26 , may be utilized, such as, but not limited to, no-gos, snap latches, anchor latches and shearable anchor latches. A spacer  42  may be included in isolation assembly  30  to accurately position it relative to a receiver  26  and its respective flow section  28 . It is noted that locating device  40  may be positioned above or below swellable material  38  to correspond to its respective receiver  26  and anticipated flow section  28  of completion assembly  14 . 
     Deployable isolation assembly  30  may further include a receiver connector  44  adapted for mating with a locating and anchoring device  40  of a subsequent isolation assembly  30 . In this configuration, as described above, one or more isolation assemblies  30  may be stacked one atop another to progressively isolate lengths of flow section  28 . For example, a first isolation assembly  30  is run into completion assembly  14  and positioned via receiver  26   b  at flow section  28   b . Later in the production life, as flow section  28   a  produces water, a subsequent isolation assembly  30  may be run into completion assembly  14  and connected via locating device  40  and receiver connector  44  to isolate flow section  28   a.    
     Swellable material  38  is a material that expands upon contact with fluid in the wellbore. Swellable material  28  may be of various compositions including, but not limited to, nitrite, neoprene, natural rubber, and AFLAS. In an initial position, swellable material  38  has an outside diameter of less than the internal diameter of the interior  32  of completion assembly  14 . Upon being positioned within completion assembly  14  and contacting the fluid in wellbore  12 , material  38  expands to a sealing position. In the sealing position, swellable material  38  expands outwardly from mandrel  34  to completion assembly  14  sealing the annulus between the two assemblies. 
     With reference to  FIGS. 1 and 2  an embodiment of a method of providing zonal isolation in a wellbore completion is described. Before completion of wellbore  12 , the various formation zones  24  of interest are identified. Formation zones  24  that are anticipated to require isolation during the life of the well are identified. For example, it is anticipated that zone  24   b  will produce water first and then at a later date zone  24   a  will produce water and require isolation. 
     A completion assembly  14  is selected having flow sections  28   a  and  28   b  corresponding to flow zones  24   a  and  24   b  respectively. In one embodiment, a receiver  26   b  is positioned in completion assembly  14  at a known spacing below flow section  28   b . A receiver  26   a  may also be positioned at a known location between flow sections  28   a  and  28   b  for either isolating flow section  28   a  after flow section  28   b  or for isolating flow section  28   a  instead of flow section  28   b , for example when flow zones  24   a  and  24   b  are different producing formations. 
     A deployable isolation assembly  30  for the selected completion assembly  14  is selected. The selected deployable isolation assembly has a swellable material  38  with dimensions suitable for positioning in selected completion assembly  14  and of a length sufficient to seal across anticipated zone  24 . A spacer  42  is selected of a length to position swellable material  38  across the desired flow section  28  relative to the selected receiver  26 . 
     Wellbore  12  is completed with selected completion assembly  14 . The completion may be open hole or include casing  16  has shown in  FIG. 1 . If wellbore  16  is cased, it is perforated at the desired section. The completion may further include gravel packing. Although the system of the present invention may be used in non-gravel packed wells, it is particularly suited and beneficial in gravel pack completions. 
     When it is desired to isolate anticipated zone  24   b , such as due to excessive water production, selected isolation assembly  30  is deployed. Selected isolation assembly  30  is run into the interior  32  of completion assembly  14  via coiled tubing, slick line, wire line or other means. Locating device  40  is landed in the cooperative receiver  26   b , positioning swellable material  38  adjacent to anticipated zone  24   b  and its respective flow section  28   b.    
     Within a time prescribed by the particular swellable material  38  and wellbore  12  conditions, swellable material  38  expands from its initial position to a sealing position. In the sealing position, swellable material  38  blocks fluid flow from the exterior of completion assembly  30  into interior  32  and into internal bore  36  of isolation assembly  30 . 
     When it is desired to isolate zone  24   a  through flow section  28   a  a subsequent isolation assembly  30  is deployed. In one embodiment, the subsequent isolation assembly  30  is run into completion assembly  14  and its locating device  40  is mated with receiver connector  44  of the preceding isolation assembly  30 . In another method, the subsequent isolation assembly  30  is run into completion assembly  14  and connected via receiver  26   a  positioning it in a isolation position proximate flow section  28   a  and flow zone  24   a.    
     Refer now to  FIG. 3 , wherein another embodiment of deployable isolation assembly  30  further includes an anchoring device  50 . Anchoring device  50  engages completion assembly  14  providing additional anchoring of assembly  30  when needed or desired. 
     In the illustrated embodiment, anchoring device  50  is an inflatable packer positioned above swellable isolation member  38 . It should be noted that other anchoring devices may be utilized. Anchor  50  may be positioned in various locations relative to isolation member  38  to secure isolation assembly  30  to completion assembly  14 . 
     From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a system and method for providing zonal isolation in a wellbore that is novel has been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow.