Abstract:
An apparatus and method for use in a well having at least three zones includes at least three sand control assemblies for positioning proximal respective zones. A flow assembly defines at least three flow conduits to respectively communicate with the at least three zones, where each of at least two of the flow conduits includes an annular path. At least three flow control devices respectively control flow of the at least three flow conduits.

Description:
BACKGROUND OF INVENTION  
       [0001]     It is common for wells to include multiple zones. A completion string positioned in a well to produce fluids from one or more zones may include casing, production tubing, packers, valves, pumps, and other components. One or more well sections may be perforated using a perforating gun string to create openings in the casing and to extend perforations into corresponding zones. Fluid flows from the zones through the perforations and casing openings into the wellbore and up the production tubing to the surface.  
         [0002]     In many wells, sand control has to be performed to prevent the production of sand along with hydrocarbons through the production string. Sand control is typically accomplished by use of sand face completion hardware, which typically includes a sand screen. In a well having multiple zones, the presence of certain completion hardware, such as sand face completion hardware, may complicate the placement of flow control conduits and flow control valves. The complexity of completion hardware associated with completing a well with multiple zones can lead to increased expenses associated with operating the well. Also, in some cases, the presence of completion hardware for multiple zones may prevent convenient intervention operations.  
       SUMMARY OF INVENTION  
       [0003]     In general, enhanced methods and apparatus are provided to complete a well having multiple zones. For example, an apparatus for use in a well having at least three zones includes at least three sand control assemblies for positioning proximal respective zones. The apparatus further includes a flow assembly defining at least three flow conduits to respectively communicate with the at least three zones, where each of at least two of the flow conduits includes an annular path. At least three flow control devices respectively control flow in the at least three flow conduits.  
         [0004]     Other or alternative features will become apparent from the following description, from the drawings, and from the claims. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0005]      FIG. 1  illustrates a completion string incorporating an embodiment of the invention.  
         [0006]      FIGS. 2A-2C  are cross-sectional views of the completion string of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0007]     In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments are possible.  
         [0008]     As used here, the terms “up” and “down”; “upper” and “lower”; “upwardly” and downwardly”; “upstream” and “downstream”; “above” and “below”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly described some embodiments of the invention. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or other relationship as appropriate.  
         [0009]      FIG. 1  is a general view of a completion string positioned in a well  100 . Although the well  100  depicted in  FIG. 1  has one wellbore, it is contemplated that a well can have multiple bores, such as multilateral or branch bores. The well  100  has at least three zones  102 ,  104 , and  106 . In other implementations, the well  100  may have additional zones (such as four or more). The zones  102 ,  104 , and  106  are stacked one above another generally along an axial direction of the wellbore  100 . In this stacked arrangement, particularly when sand control equipment is used, it is sometimes difficult to provide flow conduits through the completion string in an efficient manner.  
         [0010]     In accordance with some embodiments of the invention, three flow conduits  108 ,  110 , and  112  are provided by a flow assembly in the completion string. In the implementation of  FIG. 1 , the first flow conduit  108  communicates with the zone  102  through a first sand control assembly  114 . The second flow conduit  110  communicates with the second zone  104  through a second sand control assembly  116 . The third flow conduit  112  communicates with the third zone  106  through a third sand control assembly  118 . Note that in the depiction of  FIG. 1 , the zone  102  is the most distal zone of the well from the well earth surface, whereas the zone  106  is the most proximal zone to the well earth surface.  
         [0011]     The first flow conduit  108  extends through the inner bore of a tube or pipe. As used here, the term “tube” or “pipe” refers to an elongated structure that defines an inner bore. The elongated structure can be formed of one segment or of plural segments that are attached or coupled to each other. Although some embodiments of a “tube” or “pipe” are generally cylindrical in shape, other embodiments of a “tube” or “pipe” do not have to be cylindrically shaped. The terms “tube” and “pipe” are used interchangeably.  
         [0012]     The second flow conduit  110  is an annular path that is defined outside of the tube that defines the first flow conduit  108 . In some embodiments, the second flow conduit  110  is the annular path between a first tube containing the first flow conduit  108  and a second tube having a larger diameter than the first tube.  
         [0013]     Similarly, the third flow conduit  112  is an annular path that is defined outside of the second tube. The third flow conduit  112 , in some embodiments, is defined between the second tube and a third tube having a larger diameter than the second tube. A portion of the third flow conduit  112  includes a wellbore annulus region  120 , according to one embodiment.  
         [0014]     Also shown in  FIG. 1  are several packers  122 ,  124 ,  126 ,  128 ,  130 , and  132 . In other implementations, the number of packers can vary. The packers are provided to provide isolation between zones. Thus, any number of packers that provide adequate isolation between zones can be employed.  
         [0015]     Flow control devices are also part of the completion string to control fluid flow in the flow conduits  108 ,  110 , and  112 . A first flow control device  134  controls fluid flow through the first flow conduit  108 . In one implementation, the first flow control device  134  is a ball valve that is actuatable between an open position and a closed position.  
         [0016]     In other embodiments, other types of valves can be used in the flow control device  134 . Examples of other valves include flapper valves, sleeve valves, barrel valves, and so forth.  
         [0017]     A second flow control device  136  controls fluid flow in the second flow conduit  110 . In one implementation, the second flow control device  136  includes a sleeve valve, although other types of valves can be used in other embodiments.  
         [0018]     A third flow control device  138  controls fluid flow in the third flow conduit  112 . Again, the third flow control device  138  is implemented as a sleeve valve in one embodiment. In other embodiments, the flow control device  138  can be implemented with other types of valves.  
         [0019]     Each of the flow control devices  134 ,  136 , and  138  is remotely actuatable by use of signals transmitted from the well surface to the flow control devices  134 ,  136 , and  138 . For example, the flow control devices  134 ,  136 , and  138  can be electrically activated between open and closed positions. Electrical activation can be accomplished by using electrical lines run from the well surface to the flow control devices. Alternatively, hydraulic pressure can be used to control the flow control devices  134 ,  136 , and  138 . The hydraulic pressure can be communicated through control lines that are run from the well surface. Pressure pulses can also be transmitted through fluids in the wellbore to perform actuation of the flow control devices. Also, fiber optic lines can be run from the well surface, with optical signals transmitted through the fiber optic lines to control the flow control devices. Remote mechanical actuation can also be performed by use of mechanical signals (such as by lifting and dropping a portion of the completion screen in a predetermined sequence to control activation of the flow control devices  134 ,  136 , and  138 ). Wireless techniques, such as electromagnetic, seismic, and acoustic telemetry, may also be used to communicated with the flow control devices.  
         [0020]     In other embodiments, the flow control devices  134 ,  136 , and  138  are multi-position flow control device having at least one additional position between on and off.  
         [0021]     Once activated, each of the flow control devices  134 ,  136 , and  138  controls fluid communication between the flow conduits  108 ,  110 , and  112 , respectively, and a flow path  140  that extends upwardly, such as to the well surface through a production tubing.  
         [0022]     Although not shown, sensors (e.g., flow rate sensors, pressure sensors, temperature sensors, etc.) can also be provided in the flow conduits  108 ,  110 , and  112 . The sensors are provided to measure characteristics associated with fluid flow from the zones  102 ,  104 , and  106 .  
         [0023]      FIGS. 2A-2C  provide cross-sectional views of a portion of the completion string of  FIG. 1 . The bottom part of  FIG. 2C  shows the lower-most packer  122  and sand control assembly  114 . The sand control assembly  114  includes two sand screens  200  and  202  stacked one on top of the other. In other implementations, one sand screen can be used in the sand control assembly  114 . Fluid flows from surrounding formation (of the first zone  102 ) through the sand screens  200  and  202  into an inner bore  204  defined by a first tube  206 . Note that the first tube  206  includes many segments as depicted in  FIGS. 2A  Rather than label each of these segments with a different reference number, the segments are referred to collectively as a “tube”  206 . The segments of the tube  206  include all segments that define the inner bore  204 , which is part of the first flow conduit  108 . An isolation sub  208  includes a ball valve  210 . During run-in of the completion string, the ball valve  210  is in a closed position. However, once the completion string is installed, the ball valve  210  is opened and kept open during production. The ball valve  210  has a bore through which intervention equipment can pass.  
         [0024]     The inner bore  204  (and first flow conduit  108 ) extend through the packer  124  that is located above the isolation assembly  208 . The flow conduit  108  also extends through another packer  126  located above the packer  124 . The packer  126  is connected to the second sand control assembly  116 , which also includes a sand screen  212 . As shown at the top part of  FIG. 2C , flow from the surrounding formation (in zone  104 ) passes through the sand screen  212  into an annular path  214  that is defined outside the tube  206  defining the first flow path  108 . The annular path is defined between the first tube  206  and a second tube  216  ( FIG. 2B ) that has a larger diameter than the first tube  206 . The second flow conduit  110  extends through the annular path between the first tube  206  and the second tube  216 . As with the first tube  206 , the second tube  216  also includes multiple segments, which are collectively referred to as “tube”  216 .  
         [0025]     The first and second flow conduits  108  and  110  extend through the next upper packer  128 . The packer  128  is connected to the third sand control assembly  118 , which includes a sand screen  218 . Fluid flows through the sand screen  218  into an annular path  220  defined between the second tube  216  and a third tube  222 . The annular region  220  is part of the third flow conduit  112 . The first, second and third flow conduits extend through the next packer  130 .  
         [0026]     In one embodiment, at least portions of the first, second, and third tubes have a common axis. In other words, these portions of the first, second, and third tubes are concentric.  
         [0027]     The third flow conduit  112  extends into the well annulus  120  outside the second tube  216 . The ball valve  134  is located in the first flow conduit  108  (see the upper part of  FIG. 2B ) to control fluid flow between the first flow conduit  108  and the flow path  140  in a production tubing. The ball valve  134  is remotely actuatable to rotate between open and closed positions. A sleeve valve  136  is provided slightly above the ball valve  134  to control fluid flow in the second flow conduit  110 . The sleeve valve  136  is slidable up and down (by remote actuation) to enable opening and closing of a port between the annular path  214  and the flow path  140 .  
         [0028]     As depicted in  FIG. 2A , the third flow conduit  112  extends through the well annulus  120  to the sleeve valve  138 , which is slidable up and down (by remote actuation) to open and close ports between the well annulus  120  and the flow path  140 .  
         [0029]     In operation, depending on which of the zones  102 ,  104 , and  106  are to be produced, one of the flow control devices  134 ,  136 , and  138  is actuated to the open position, while the remaining two flow control devices are maintained in the closed position. Alternatively, if multiple zones are to be produced, then two or more of the flow control devices  134 ,  136 , and  138  can be opened, with fluids from the multiple zones commingled for production in the flow path  140  to the well surface. In other implementations, instead of producing fluids from zones  102 ,  104 , and  106 , injection can be performed in which fluid is injected into one or more of the zones  102 ,  104 , and  106 . In similar fashion, the flow control devices  134 ,  136 , and  138  control injection of fluids into respective zones  102 ,  104 , and  106 .  
         [0030]     Another valve can also be stacked in the lower completion (such as below sand control assembly  114 ) to incorporate flow from an additional zone, if desired. Such valve would provide selective fluid communication between the additional zone and the flow conduit  108 .  
         [0031]     By using the flow assembly according to some embodiments of the invention, convenient placement of flow control devices in conjunction with sand control equipment can be accomplished. Also, by using the flow assembly according to some embodiments, intervention operations are made more convenient.  
         [0032]     While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. For instance, the present invention may be installed in a land as well as a subsea wellbore. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.