Abstract:
A system and method is provided for utilizing both a wellbore completion and a formation treatment system. The formation treatment system comprises a bypass that directs well treatment fluid around the wellbore completion. The bypass protects the wellbore completion from potentially corrosive or erosive well treatment fluids which, in turn, allows the wellbore completion to remain downhole during the introduction of well treatment fluids.

Description:
BACKGROUND  
       [0001]     In a variety of subterranean environments, such as wellbore environments, downhole completions are used to facilitate the production of desired fluids. For example, completions often are utilized in the production of fluids, such as petroleum, water and gas. The completion is located in a wellbore, and the fluids are pumped or otherwise produced to a desired location.  
         [0002]     Well treatments sometimes are used before, during or after the production of fluids to affect well characteristics. For example, a well treatments may comprise well stimulation in which fluids are pumped downhole to stimulate subsurface formations. Due to the corrosive and/or erosive characteristics of some of these stimulation fluids, the well completion can be damaged if not removed prior to treatment.  
       SUMMARY  
       [0003]     In general, the present invention provides a system and methodology to facilitate subsurface formation treatment. The approach utilizes a diverter and a bypass to direct treatment fluids around the completion components as the treatment fluids are flowed to the desired formation region. Thus, completion equipment may remain in the wellbore during stimulation or other treatment of subsurface formations without incurring damage from the treatment fluids.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]     Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:  
         [0005]      FIG. 1  is a schematic illustration of a system for producing fluid and treating a subsurface formation, according to an embodiment of the present invention;  
         [0006]      FIG. 2  is a cross-sectional view taken generally along line  2 - 2  of  FIG. 1 ;  
         [0007]      FIG. 3  is a schematic illustration similar to  FIG. 1  with the system in a fluid producing configuration, according to an embodiment of the present invention;  
         [0008]      FIG. 4  is a schematic illustration of an alternate embodiment of the system illustrated in  FIG. 1 ; and  
         [0009]      FIG. 5  is an illustration similar to that of  FIG. 4  with the system in a well treatment configuration. 
     
    
     DETAILED DESCRIPTION  
       [0010]     In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.  
         [0011]     The present invention generally relates to a system and method for utilization and treatment of wells. The system and method render compatible a variety of downhole completions and well treatment systems. However, the devices and methods of the present invention are not limited to use in the specific applications that are described herein.  
         [0012]     Referring generally to  FIG. 1 , a system  20  is illustrated according to an embodiment of the present invention. System  20  is disposed in a subterranean environment, such as a subsurface formation  22  currently or previously holding fluids, e.g. petroleum, water and/or gas. As illustrated, a wellbore  24  is formed, typically by drilling, in formation  22 . The wellbore  24  may be lined with a casing  26  having perforations  28 . Perforations  28  provide a passage for fluid flowing from formation  22  into wellbore  24  or for treatment fluids flowing from wellbore  24  into formation  22 .  
         [0013]     System  20  comprises a completion  30  deployed at a desired location in wellbore  24  by a deployment system  32 . Deployment system  32  may comprise a tubing  34 , such as production tubing or coil tubing. Tubing  34  defines an internal flow path  36  along which fluids can be directed toward or away from completion  30 .  
         [0014]     Although completion  30  may have a variety of configurations, one example is an electric submersible pumping system  38  used to produce fluids from formation  22  through tubing  34  to a desired collection point. Electric submersible pumping system  38  may be constructed with a variety of components and component arrangements depending on the specific application. By way of example, however, the electric submersible pumping system may comprise a pump  40 , a pump intake  42 , an electric motor  44  and a motor protector  46 . Motor  44  powers pump  40  which draws fluid from wellbore  24  through pump intake  42 . As the fluid is pumped, additional fluid from formation  22  flows into wellbore  24  through perforations  28 . Electrical power may be supplied to motor  44  by an appropriate power cable  47 .  
         [0015]     System  20  also comprises a well treatment system  48 . Treatment system  48  utilizes a diverter valve  50  and a bypass  52  for directing fluid to a specific region of the wellbore. For example, bypass  52  may be used to route treatment fluids past completion  30 . Bypass  52  defines a flow path  54  that may be disposed within a conduit  56 . Conduit  56  may be in the form of a shroud or a tube, such as that illustrated in  FIGS. 1-3 . Conduit  56  extends from diverter valve  50  to a discharge outlet  58 . In the embodiment illustrated, diverter valve  50  is disposed in tubing  34  above or on the downstream side of completion  30 , and discharge outlet  58  is disposed below or on the upstream side of completion  30 . Thus, the potentially corrosive or erosive well treatment fluids can be directed past completion  30  via conduit  56  to avoid detrimental contact between the well treatment fluid and the completion.  
         [0016]     As further illustrated in  FIG. 1 , conduit  56  may be disposed between completion  30  and casing  26 . Increased conservation of wellbore space can be achieved by placing conduit  56  adjacent the exterior surface of completion  30 , as illustrated in  FIG. 2 . Additionally, the cross-sectional shape of conduit  56  can be elongated and/or wrapped about the exterior surface of completion  30  to further reduce the annular space required by bypass  52  (see  FIG. 2 ).  
         [0017]     Diverter valve  50  may comprise a variety of valve types depending on the specific application and design parameters. For example, diverter valve  50  may comprise a ball valve or a flapper valve. Diverter valve  50  is adjustable between at least two positions that alternately enable the downflow of well treatment fluids through tubing  34  and bypass  52 , as illustrated in  FIG. 1 , and the upflow of fluids produced by completion  30  through tubing  34 , as illustrated in  FIG. 3 .  
         [0018]     In  FIG. 1 , diverter valve  50  is illustrated in a first position  60  in which fluids flowing downwardly through tubing  34  are blocked from reaching completion  30 . Instead, the well treatment fluids are diverted into conduit  56  and directed past completion  30 . The well treatment fluids are discharged from bypass  52  at discharge outlet  58  to accomplish the desired well treatment. For example, well stimulation fluids may be directed through bypass  52  and into wellbore  24  proximate perforations  28  to facilitate the flow of stimulation fluid from wellbore  24  into formation  22 .  
         [0019]     In  FIG. 3 , diverter valve  50  is illustrated in a second position  62  in which fluids flowing upwardly through tubing  34  from completion  30  are blocked from entering bypass  52 . Thus, well fluids that collect in wellbore  24  are readily produced to a desired collection point without interference from bypass  52 .  
         [0020]     Actuation of diverter valve  50  may be accomplished in a variety of ways depending on the design and application of the valve. For example, diverter valve  50  may be a simple flapper valve having a flapper that is moved between the first and second positions  60 ,  62  by fluid flow. In other words, the downward flow of well treatment fluid in tubing  34  can be used to move diverter valve  50  to the first position  60  in which flow to completion  30  through tubing  34  is blocked (see  FIG. 1 ). Similarly, the upward flow of fluid produced by completion  30  through tubing  34  can be used to move the valve to its second position  62  in which flow to bypass  52  is blocked (see  FIG. 3 ). Alternatively, diverter valve  50  may be controlled by inputs received through a control line  64 . Control line  64  may be used to provide, for example, hydraulic or electrical inputs that actuate diverter valve  50  between at least first position  60  and second position  62 .  
         [0021]     An alternate embodiment of system  20  is illustrated in  FIGS. 4 and 5 . In this embodiment, completion  30  further comprises one or more packers  66  used to divide the wellbore into zones. For example, in the illustrated embodiment, a single packer  66  is used to divide wellbore  24  into an upper zone  68  and a lower zone  70 . In this embodiment, the electric submersible pumping system  38  is disposed in lower zone  70  and is operable to displace fluids from the lower zone through a passage  72  in packer  66  via tubing  34 , as illustrated in  FIG. 4 . Also, well treatment fluids may be injected downwardly through packer  66 , via passage  72  and tubing  34 , and into bypass  52 , as illustrated in  FIG. 5 . Alternatively, packer  66  may be formed with a secondary passageway  74  to enable passage of well stimulation fluids through packer  66 , as illustrated by dashed lines in  FIG. 5 . In this latter embodiment, diverter valve  50  is placed on a side of packer  66  opposite that of electric submersible pumping system  38 .  
         [0022]     Although only a few embodiments of the present invention have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this invention. Accordingly, such modifications are intended to be included within the scope of this invention as defined in the claims.