Abstract:
Disclosed herein is a lateral monitoring and/or control system. The system includes at least one splitter having a lateral bore and a main bore, at least one control line at the splitter and at least one of a choke module, monitoring module, flow venturi module and a control module disposed in operable communication with the lateral bore and outside of the main bore. Further disclosed herein is a method for controlling and/or monitoring of a multi-lateral well system. The method includes installing one or more splitter in a borehole, installing at least one control line to communicate remotely with each of the one or more splitters selectively communicating with one or more of at least one of a monitoring module, control module, choke module and flow venturi module.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/673,529 filed Apr. 21, 2005, the contents of which are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND  
       [0002]     In the hydrocarbon industry it is becoming more and more common to employ multiple branches known as laterals from a main leg of a wellbore. Wells having this characteristic are known as multilateral wellbores. Multilateral wellbores are advantageous because they, by definition, access different areas of a hydrocarbon bearing formation from a single surface location. This is desirable from a cost standpoint for capital expenditure as well as having a much lesser impact on the surface environment.  
         [0003]     Important with respect to multilateral wellbores is control and/or monitoring of fluids produced. It is desirable to monitor produced fluids to optimize production or so that action might be taken to avoid contamination of the well due to, for example, early water breakthrough in one of the laterals.  
         [0004]     One of the problems associated with current monitoring and control schemes is that a large number of devices may need to be pulled from the well if entry to a more downhole portion of the well is required. Alternatively, entry may be had to remote portion of the well by using a device small enough to be run through the completion tubing but such devices are inherently small in size. In some cases, devices small enough to be run through the completion string are insufficient desirably address whatever issue prompted the run.  
       SUMMARY  
       [0005]     Disclosed herein is a lateral monitoring and/or control system. The system includes at least one splitter having a lateral bore and a main bore, at least one control line at the splitter and at least one of a choke module, monitoring module, flow venturi module, and a control module disposed in operable communication with the lateral bore and outside of the main bore.  
         [0006]     Further disclosed herein is a method for controlling and/or monitoring of a multi-lateral well system. The method includes installing one or more splitter in a borehole, installing at least one control line to communicate remotely with each of the one or more splitters selectively communicating with one or more of at least one of a monitoring module, control module, choke module and flow venturi module. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     Referring now to the drawings wherein like elements are numbered alike in the several Figures:  
         [0008]      FIG. 1  is a perspective partial cutaway view of a stackable splitter portion of the system disclosed herein with two auxiliary ports for monitoring and controlling modules;  
         [0009]      FIG. 2  is a schematic view of a leg and an auxiliary bore that is parameter transmissively connected; and  
         [0010]      FIG. 3  is a schematic view of a leg and an auxiliary bore that is fluid transmissively connected. 
     
    
     DETAILED DESCRIPTION  
       [0011]     Referring to  FIGS. 1 and 3 , the lateral control and monitoring system  10  comprises a stackable splitter  12  having an uphole main bore  14 , a downhole main leg  16 , and a downhole lateral leg  18 . The splitter may be embodied as a casing segment or tubing segment. Where the splitter is a casing segment, it is cementable in the hole. It is important to note that the concept hereof provides for one or more of control (decision-type control or flow-type control) and monitoring of a lateral leg of the splitter while leaving the main leg of the splitter (and hence the junction itself) fully open. The method for providing such control/monitoring while leaving the main bore open can be practiced using the splitter illustrated herein either with ancillary bores (described hereunder) or without the ancillary bores, the overriding consideration being the leaving of the main bore patent so that access to laterals and their controls can be gained without pulling a large number of completion string components from the main bore simply to “get to the lateral”. There are clear benefits to arrangements facilitating the ability to reach target laterals from uphole without pulling monitoring or control modules from uphole splitters to gain access thereto. Further, one embodiment the disclosed splitter further provides for a location (which would otherwise be unused space) in which to place components of a downhole system and from which location (referred to herein as the “ancillary bore(s)”) the installed components are retrievable. Since in this embodiment too, the main bore is left open, access to individual control or monitoring modules whether in the lateral leg or in the ancillary bore of splitters that are farther downhole than the subject splitter does not require removal of such components from splitters farther uphole than the subject splitter.  
         [0012]     The concept hereof provides for arrangement of modules and control lines in different configurations for different applications all of which maintain an open main bore. This can be in a tubing string and/or a casing string in different systems with differing overall properties. As noted above, control and/or monitoring modules are to be placed so as to interact with a target lateral (or potentially monitor parameters of the main bore) but not occlude the main bore. Thereby, greater access and tighter controls simultaneously with easier maintenance, repair or replacement of components is achieved. In some of the embodiments, components are located directly in the lateral. For example, a choke intended to control flow from a particular lateral or a flow venturi intended to measure flow from or to a particular lateral would be positioned in that lateral. A monitoring or control system however might be located in an ancillary bore and merely have sensors located in the lateral, or may simply have sensors exposed to the lateral (or the main bore) while not being directly in the lateral (or main bore). More particularly (see  FIGS. 2 and 3 ), ancillary bores may be configured with a parameter transmissive interface  40  (temperature, pressure, etc.) or fluid transmissive interface  42  providing for communication with the lateral bore, main bore, or both. In one example a connective opening (interface  40 ) between the ancillary bore and lateral bore or main bore includes a flexible barrier  44  therein and as such is not fluid transmissive but is parameter transmissive. In another example ( FIG. 3 ), the connective opening (interface  40 ) is free of a barrier and so in addition to being transmissive to parameters such as temperature and pressure it is also fluid transmissive. It is noted however that each of the devices utilized for a particular application could be placed in the lateral and no ancillary bore provided while remaining in keeping with the unifying principle of this disclosure, which is to maintain the patency of the main bore. In applications utilizing one or more ancillary bores, referring to  FIG. 1 , the ancillary bores  20 ,  22  are located in what would otherwise be dead space in a splitter. That is, the space along a diametric line perpendicular to (and in the same plane of) a diametric line, which bisects lateral leg  18  and main leg  16 . The ancillary bore(s)  20 ,  22  are configured to provide signal transmitting capability to other well components including intelligent components, such as monitors, controllers, sensors, etc. and control components such as chokes and other downhole tools. Moreover the ancillary bore(s) may be configured to receive a controller configured to communicate with multiple addressable devices or individual control and monitoring modules. In the event two ancillary bores are provided as illustrated, it is to be understood that they need not both be used. Indeed neither of the bores need be used. They may stay plugged with, for example, dummy modules, indefinitely. One or both may be employed at will for monitoring, control or combination equipment. In the prior art this would have been unused space and is beneficially utilized according hereto to house control and/or monitoring modules(s)  30 ,  32  in a retrievable manner. Such control and monitoring modules  30 ,  32  are operably connected to surface or other remote location via control line(s)  34  which may be hydraulic, electric, optic or otherwise or may be combinations of any of these. In one embodiment, the control lines are run outside of the casing segment and penetrate the casing splitter at the ancillary bore or lateral bore or even the main bore to provide communication and/or power for a module of some kind stabbed therein from within the string.  
         [0013]     Whether or not ancillary bores are utilized, the disclosure hereof specifically facilitates well control and monitoring control. These can be done alone or in combination. With these two concepts in place, any well configuration is handleable. Where multiple splitters are stacked, flows come from several different regions of a host formation, through lateral bores that extend thereinto. Because of the configuration taught herein, all of these flows are quantified, which then provides a true picture of one condition in the entire well. Where it is known, as in the system of this disclosure, (through monitor, control or both) what condition is prevailing at each of the laterals of a well the condition of the entire well must necessarily be known because it is the sum of its parts. In some embodiments hereof, each downhole control unit installed is addressable so that fewer or even one control line need be installed to communicate with one or more control and/or monitoring units or modules downhole.  
         [0014]     Installation of the described device includes running the splitter  12  and cementing it in the wellbore (if a casing segment). If the particular splitter includes ancillary bore(s), dummy modules  30 ,  32  (as shown) may be installed therein to prevent debris from entering the ancillary bore(s), which might otherwise present difficulties with respect to installation of modules. A straddle wiper plug (not shown), as known in the art, may be employed to prevent cement entrance to profiles in the splitter if the splitter is a casing segment and intended to be cemented in place. In the casing splitter embodiment, once the splitter  12  is at depth it is cemented in place. A lateral bore may be drilled and lined, etc. and suitable device(s) installed. The device(s) may be, as noted above, a controller module, a monitoring module, an adjustable choke  24 , a venturi, a combination of the foregoing or other downhole tools. These are installed in leg  18  to control flow between lateral leg  18  and the main bore. These can alternatively be installed in ancillary bores as noted above, in which case, not only will they not impede access down the main bore, but they also will not impede access down the lateral bore. Modules  30 ,  32  if used, may be installed with such tools as a diverter or kick over tool to replace one or both dummys. It should be noted that the splitter could be configured to accept two or more modules in a single module receptacle, if desired.  
         [0015]     A very significant advantage of this system is that access to more downhole laterals of the well may be had without the need to remove devices connected with more uphole laterals.  
         [0016]     The choke  24 , which may be an adjustable choke and in one embodiment is variable from fully open to fully closed (thereby shutting off the lateral), is configured to land and be retained in lateral leg  18 . Choke  24  is also retrievable. The configuration, in one embodiment employs a profile (see  FIG. 2 )  26  at an uphole end  28  of lateral leg  18  to receive choke  24 . Choke  24  may be installed at any time in the well construction program. The profile  26  comprises, in one embodiment, an existing nipple configuration such as for example that utilized in Baker Oil Tools Product Number H80185, a Model AF Seating Nipple.  
         [0017]     While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.