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BACKGROUND 
     The formation of wellbores for the purpose of exploration or extraction of natural resources such as oil, gas, and water is a valuable yet time consuming and expensive field. Completion of wellbores includes the process of making a well ready for production or injection. Some types of completion systems include a tubular which supports subs enabling a frac pack operation, isolation packing, and gravel pack operations, and production sleeves having screens for bringing production fluid from downhole to surface. Once wells are completed using this type of completion system, production tubing and associated downhole tools can be run into the wellbore. 
     Advances in completion technology have led to the emergence of multi-zone systems where zones within the formation are separated, such as by packers and sand control configurations and operations, and each zone can be separately treated, fractured, or produced from, which saves time and inevitably reduces expenses. A multi-zone single trip (“MST”) completion system reduces time and expenses even further by completing multiple zones in one trip. 
     A multi-zone single trip (“MST”) completion system is shown in  FIGS. 1A and 1B . The MST system includes a number of subs attachable together to form a completion string  10 . It should be understood that only a portion of the completion string  10  is shown, as the completion string  10  can include as many subs, tubing joints, and sleeves necessary for spanning as many zones as desired. As shown in  FIG. 1A , the completion string  10  includes, in part, an automatic locating assembly or “autolocator”  12  to locate the completion string  10  in its various conditions such as, but not limited to pickup, run in, and set down positions. Inverted seals, which can include uphole and downhole inverted seals  14 ,  16 , are provided within an inner diameter of the completion string  10  and are usable in a fracing operation. An isolation packer  18  is included in the completion string  10  and may include slips for engaging a casing or wellbore. The isolation packer  18  is located between the uphole inverted seals  14  and a frac sleeve  20 . The frac sleeve  20  of the completion string  10  is located between the isolation packer  18  and downhole inverted seals  16 . 
     The completion string  10  for multi-zone applications further includes multiple sets of the illustrated features which are spaced out with screen joints and production sleeves in between for production purposes, as shown in  FIG. 1B . As shown in  FIG. 1B , and downhole of the frac sleeve  20  and inverted seals  16 , the MST system further includes shear out safety joint  24 , production valves, also known as production sleeves  26  having a selective profile, that are capable of opening and closing depending on whether or not a particular zone should be opened for production, and a screen  28  extending along the length of the production zone. In one exemplary embodiment, a standard well is completed using a service string consisting of, but not limited to, a frac port, opening tool, and closing tool (not shown). Upon completion of the final zone, the service string may be removed from within the completion string  10 . Upon removal, the closing tool on the service string closes all sleeves as it traverses through the completion string  10  in the uphole direction. Removal of the service tool leaves a bore  22  in the completion string  10  for receiving the production string. Production tubulars are then run into the wellbore and are connected to the completion string  10  enabling a continuous bore to surface. A separate opening/closing tool (not shown) can then be run in the completion string  10  for selectively opening and closing the production sleeves  26  to initiate production through the production string, where such determination may be made by an operator or by a sensing device, however this requires additional time since the opening/closing tool then needs to be removed from the completion string  10 . Thus, production is initiated by selectively opening and/or closing selected production sleeves  26  using a work string such as by wireline, coiled or standard tubing. When multiple zones are accessed with the completion system  10 , subsequent opening and/or closing of other selected production sleeves  26  requires additional runs of the work string. 
     BRIEF DESCRIPTION 
     A production string employable in a multi-zone completion system, the production string includes a passageway enabling passage of production fluids therethrough; a shifting tool including a shifting profile engageable with a production sleeve of the completion system to open a closed production sleeve, the shifting tool sharing the passageway of the production string; and, a remotely controlled hydraulic production valve which controls fluid flow between the passageway and the production sleeve. 
     A production method useable in a borehole, the method includes making up a production string with a shifting tool and hydraulic valve for one or more zones of a completion system, each shifting tool having a passageway of the production string; lowering the production string into the completion system; opening one or more production sleeves of the completion system using respective shifting tools of the production string; and, selectively opening desired hydraulic valves with control line pressure, wherein production from selected zones occurs between respective production sleeves and the passageway. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIGS. 1A and 1B  depict cross sectional views of portions of a standard completion system of the prior art; 
         FIGS. 2A and 2B  depict cross-sectional views of portions of an exemplary embodiment of a production string; 
         FIG. 3A  depicts a cross-sectional view of an exemplary embodiment of a shifting tool in a crippled condition for the production string of  FIGS. 2A and 2B ; 
         FIG. 3B  depicts a cross-sectional view of the shifting tool of  FIG. 3A  in an activated condition; 
         FIG. 3C  depicts a cross-sectional view of the shifting tool of  FIGS. 3A and 3B ; 
         FIG. 4A  depicts a cross-sectional view of an exemplary embodiment of a slick joint assembly; 
         FIG. 4B  depicts a perspective view of a portion of the slick joint assembly of  FIG. 4A ; 
         FIGS. 5A-5E  depict a schematic view of an exemplary embodiment of an operation using the production string of  FIGS. 2A and 2B ; 
         FIG. 6  depicts a schematic cross-sectional view of the slick joint within the completion system; and, 
         FIG. 7  depicts the production string having a plurality of zonal sections. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Minimizing the number of trips in a borehole operation reduces time, which can significantly reduce the completion and/or recovery cost. Exemplary embodiments of a system described herein include a production string  100  insertable into a completion system, such as the MST completion system shown in  FIGS. 1A and 1B , the production string  100  including an integrated shifting tool  200  for opening and/or closing the production sleeves  26  of the completion system, thus eliminating the extra run of a work string to open and/or close the production sleeves  26 . The production string  100  may include a plurality of zonal sections, such as Zonal Section 1 and Zonal Section 2 depicted in  FIG. 7 , where each zonal section includes, in part, a shifting tool  200  having a different shifting profile thereon, a slick joint  300 , and a production valve  106 . 
     Turning now to  FIG. 2A , a portion of an exemplary embodiment of a production string  100 , which may be used in the completion string  10 , is shown. For each completed zone, the exemplary production string  100  is made to include a zonal section having a pup joint  102  for ease of handling, a hydraulically activated feed-through shifting tool  200  with correct shifting profile for a corresponding production sleeve  26 , a feed-through slick joint  300  connectable to the shifting tool  200  at non-rotatable connections  170  which align respective control line feed throughs, a gauge mandrel  104  for well monitoring purposes, a remotely operated hydraulic production valve  106 , and a quick connect tool  108  for ease of make-up on rig floor, where the above-described devices may be so arranged from an uphole to downhole direction in each zonal section as shown.  FIG. 2B  further shows a section of blank pipe  112  and a sump packer  114  of the production string  100 . The hydraulic production valve  106  remains closed until it is remotely operated to an open condition, such that even when all of the production sleeves  26  are opened, production does not begin until one or more of the production valves  106  are opened. In addition to each zone of production equipment, the production string  100  also includes a top packer (not shown) at an uphole end and anchor packer or sump packer  114  at a downhole end along with required production tubing or blank pipe  112 . Each zonal section is appropriately spaced apart from other sections of the production string  100  for aligning with the zones in the formation and with the production sleeves  26  of the completion string  10 . Standard production tubing or blank pipe  112  of appropriate lengths may separate adjacent zonal sections of the production string  100  as necessary. The pup joint  102 , gauge mandrel  104 , hydraulic production valve  106 , and quick connect tool  108  may be standard components that are added to the production string  100  in a “plug and play” method on the rig floor, and therefore the details of these components are not further described. A series of hydraulic control lines  150  run the length of the production string  100  and enable the capability of permanent monitoring and selective operation of the hydraulic production valves  106  from the surface. 
       FIGS. 3A-3C  show the hydraulically activated feed-through shifting tool  200 . The shifting tool  200  includes a first end  202  and a second end  204 . The first end  202  is typically an uphole end and the second end  204  is typically a downhole end, but the orientation may be reversed so long as the corresponding features on the completion string  10  coincide. The shifting tool  200  also includes a fluted first sub  206  and fluted second sub  208 . The fluted second sub  208  is connected to an uphole end of a mandrel  210 . The mandrel  210  includes slots machined therein, which are aligned with fluted slots on both the first sub  206  and the second sub  208 . This alignment allows multiple control lines  150  to run through the shifting tool  200  so as to be protected therein. Thus, the geometry for control line bypass does not affect the functionality or ratings of the shifting tool  200 . As shown in  FIG. 3C , five control line feed-throughs  212  are shown. Since each control line  150  connects to a hydraulic production valve  106  of a zonal section of the production string  100 , in the illustrated embodiment a total of up to five zonal sections of the production string  100  may be included, however the geometry for control line bypass may be altered to accommodate any number of control lines  150 . Additionally, if five control line feed-throughs  212  are included, five or less zonal sections of the production string  100  may be provided. 
     A collet  214  having a specific shifting profile  216  is attached to first retaining nut  218  at a first end  220  of the collet  214  and second retaining nut  222  at a second end  224  of the collet  214 . The collet  214  surrounds the second sub  208 . In an exemplary embodiment, the shifting profile  216  for a particular zonal section of the production string  100  will only function for a corresponding production sleeve  26  of the completion string  10  (shown in  FIG. 1B ). The collet  214  includes a radially expandable section  226  that carries the shifting profile  216 . The radially expandable section  226  is supported by a first collar  228  of the collet  214  between the radially expandable section  226  and the first retaining nut  218 . The radially expandable section  226  is also supported by a second collar  230  of the collet  214  between the radially expandable section  226  and the second retaining nut  222 . As shown in  FIG. 3A , a crippling sleeve  232  is shear pinned via shear pin  234  to the first collar  228  and adjacent the first retaining nut  218  in the crippled condition of the shifting tool  200 . In this crippled condition, a first end  236  of the crippling sleeve  232  is located uphole of the first collar  228  of the collet  214 , and a second end  238  of the crippling sleeve  232  is located downhole of the first collar  228  and covering at least a portion of the expandable section  226 , such that the expandable section  226  is forced radially inward as shown in  FIG. 3A . Likewise, the downhole end of the first collar  228  and the uphole end of the second collar  230  are forced radially inward towards the second sub  208  in this crippled condition. The collet  214  is slotted to allow for the contraction and expansion of the expandable section  226 . A port  244  in the second sub  208  connects a passageway  110  in the production string  100  to a closed inner space  246  formed between the crippling sleeve  232  and the second sub  208 . As shown in  FIG. 3B , internal pressure activation, via port  244 , is used to push back the crippling sleeve  232  in a direction away from the collet  214  such that the second end  238  of the crippling sleeve  232  no longer rests on the expandable section  226 , allowing the collet  214  to radially expand and push out its shifting profile  216  past an outer diameter of the crippling sleeve  232 . When thus activated, a retaining cap  240  traps a lock ring  242  at the first end  236  of the crippling sleeve  232  to prevent the crippling sleeve  232  from sliding back over the expandable section  226  of the collet  214 , such that the crippling feature of the shifting tool  200  is locked out and prevented from re-engaging with the shifting profile  216 . Since hydraulic activation is required to activate the shifting tool  200 , the shifting tool  200  remains disabled while running the production string  100  in the hole, thus preventing any premature opening of production sleeves  26 . It should be noted that the crippling sleeve  232  can be oriented to face uphole or downhole depending on preference of the operator and well conditions. Thus, the terms uphole and downhole as used herein to describe the relative orientation of features of the shifting tool  200  and other components in the production string  100  and completion string  10  may be interchangeably used. 
     In an alternative exemplary embodiment, the shifting tool  200  may be run into the well without the hydraulic crippling feature  232  assembled thereto. This will reduce a cost of the shifting tool  200  and eliminate any risk of the shifting tool  200  becoming stuck in a crippled condition, while also eliminating the need to pressure down the tubing at any point in the operation to shear the crippling sleeve  232 . Conversely, the operator will lose the ability to manipulate the shifting tool  200  within the well as many times as desired without the possibility of functioning a production sleeve. 
       FIG. 4A  shows the feed-through slick joint assembly  300 , which allows for zonal isolation. For example, if one zone begins producing water, an operator can close the associated hydraulic production valve  106  in that zone remotely and quickly. There is no need to make a run into the well and close it mechanically, which could take a full day or more depending on depth. Without the slick joint assembly  300  in each zone, the fluid from the zone producing water would flow into the annulus between the outer diameter of the production string  100  and an inner diameter of the completion string  10  and into the hydraulic production valves  106  of surrounding zones. The inclusion of the slick joint assembly  300  in the production string  100  blocks that flow from leaving the damaged zone. 
     The slick joint assembly  300  includes a first end  302 , such as an uphole end, which is closer to the shifting tool  200 , and a second end  304 , such as a downhole end, which is closer to the hydraulic production valve  106 . The slick joint assembly  300  is made up of a double pin first sub  306  which has threaded ports  308  to allow for externally pressure testable control line jam nut  310 . The jam nut  310  may be a standard component that seals against the control lines  150 , confirms pressure integrity of the control lines  150 , and enables complete zonal isolation once the assembly is in place in the well. As with the shifting tool  200 , the geometry for control line bypass in the slick joint  300  does not affect functionality or ratings of the slick joint  300 . A smooth outer diameter slick mandrel  312  is joined to the first sub  306 , such as via threading, and provides a place onto which the inverted seals  14 ,  16  can hold a pressure tight seal for zonal isolation, as shown in  FIG. 6 . An inner tubular  314  is also attached to the first sub  306  and provides a pressure tight path for production fluids to flow in the passageway  110  from the wellbore to surface after the hydraulic production valves  106  have been opened. The inner tubular  314  is capable of containing pressures expected during the production life of the well. With additional reference to  FIG. 4B , a ported second sub  316 , such as a downhole sub, connects with the inner tubular  314  and the slick mandrel  312 . The second sub  316  may slide onto the inner tubular  314  while simultaneously sliding into fingers  318  on the slick mandrel  312 . In such a configuration of a quick connect retaining feature, the second sub  316  requires no rotation during assembly so that control lines  150  can be plumbed first through feed throughs  322 , thus making assembly of the production string  100  much simpler. The assembly of the slick joint  300  is then locked together with a retaining nut  320 . 
     In an alternative exemplary embodiment, a minor modification to the slick joint  300  will allow the slick joint  300  to be run in conventional frac/gravel pack completions (either multi-zone or stack-pack). Instead of the slick joint  300  having a smooth outer diameter for sealing, the slick joint  300  may be re-configured to house traditional bonded seals which will then stab into existing seal bores already in place in the conventional frac/gravel pack completion. The slick joint  300  will then function as described above. 
     With reference to  FIGS. 5A-5B , in operation, an operator will run an MST completion system, such as completion string  10  shown in  FIGS. 1A and 1B , through a well. The well is then completed using a service tool (not shown). The service tool within the completion string  10  is then pulled from the well closing all of the production sleeves  26  on the completion string  10 . A production string  100 , such as shown in  FIG. 2 , is made up with enough tools for X number of zones, such as Zones 1 and 2 as shown in  FIG. 7 . As shown in  FIG. 5A , the production string  100  is run to final depth and space out of the well while the shifting tools  200  are crippled as shown in  FIG. 3A . The production string  100  is then picked up, as shown in  FIG. 5B , and a tubing hanger  400  is installed, the production string  100  is again lowered to depth, as shown in  FIG. 5C , and then picked up, as shown in  FIG. 5D , to a height allowing the shifting tools  200  to be placed above (uphole of) the longest interval and the tubing hanger  400  is oriented with a landing string  402  and blowout preventer “BOP”  404 . A remotely operated vehicle “ROV”  406  may be used to inspect, control, and/or manipulate these uphole portions. The shifting tools  200  are then activated by applying pressure down the tubing, such as via the passageway  110  of the production string  100  shown in  FIG. 2A . The production string  100  is then lowered, as shown in  FIG. 5E , opening all of the production sleeves  26  in the process via the shifting profiles  216  of the collets  214 , as shown in  FIG. 3B , and the tubing hanger  400  is landed. The slick joints  300 , shown in  FIG. 4A , will then be in place and sealed off on the existing inverted seals  14  or  16  as shown in  FIG. 6 , within the completion string  10  shown in  FIG. 1A , isolating each zone. The anchor packer or sump packer  114  shown in  FIG. 2B  is set with control line pressure. Once the production sleeves  26  have been opened, the operator on surface can choose to open any hydraulic valve  106  shown in  FIG. 2A  desired with control line pressure from control lines  150  and production begins from selected zones while maintaining complete zonal isolation. Each hydraulic valve  106  has the capability of being turned on or off whenever desired. Should more than one hydraulic valve be opened at a time, then comingling of the production fluid may be allowed. As described above, in some situations, a multi-zone well may be completed with multiple flow paths for production fluids, where each flow path (tubular) leads to its own zone. 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

Summary:
A production string employable in a multi-zone completion system, the production string includes a passageway enabling passage of production fluids therethrough; a shifting tool including a shifting profile engageable with a production sleeve of the completion system to open a closed production sleeve, the shifting tool sharing the passageway of the production string; and, a remotely controlled hydraulic production valve which controls fluid flow between the passageway and the production sleeve. Also included is a production method useable in a borehole.