Abstract:
A hydraulic actuator is connected between a downhole tool and a hydraulic control line for operating the downhole tool through an actuation sequence. The hydraulic actuator comprises a valve shuttle section having an inlet port in connection with the hydraulic control line, a first function port and a second function port. The hydraulic actuator also has a shuttle movable between positions providing fluid communication between the inlet port and the first function port and the inlet port and the second function port. Additionally, the hydraulic actuator has a pilot assembly in fluid connection with the hydraulic control line and in operational connection with the shuttle. The pilot assembly is movable in response to an actuation cycle comprising applying pressure from the hydraulic control line and bleeding the pressure off.

Description:
FIELD OF THE INVENTION 
   The present invention relates in general to subsurface well completion equipment and, more specifically to mechanisms for operating multiple hydraulic downhole tools from a single hydraulic line. 
   BACKGROUND 
   It is well known that many downhole tools require power to operate, or shift from position to position in accordance with the tools intended purpose. It is therefore a desire to provide hydraulic power and the ability to more than one downhole tool from a minimal number of hydraulic control lines. 
   SUMMARY OF THE INVENTION 
   In view of the foregoing and other considerations, the present invention relates to a self-piloted actuator tool assembly. 
   Accordingly, methods, apparatus and systems for controlling one or more well tools through a single hydraulic control line are provided. In an embodiment of the invention a hydraulic actuator connected between a downhole tool and a hydraulic control line for operating the downhole tool through an actuation sequence includes a valve shuttle section having an inlet port in connection with the hydraulic control line, a first function port and a second function port, and a shuttle moveable between positions providing fluid communication between the inlet port and the first function port and the inlet port and the second function port; and a pilot assembly in fluid connection with the hydraulic control line and in operational connection with the shuttle, the pilot assembly movable in response to an actuation cycle comprising applying pressure from the hydraulic control line and bleeding the pressure off. 
   An example of a multi-drop tool system for a wellbore includes a first and a second piloted actuator tool assembly connected to a pipe string and disposed in a wellbore; and a hydraulic control line connected to the first and the second piloted actuator tool assembly, wherein each piloted actuator tool assembly is controlled by actuation cycles comprising applying pressure in the hydraulic control line and bleeding the applied pressure off. 
   A method of controlling multiple downhole well tools from a single hydraulic control line includes the steps of positioning multiple piloted actuator tool assemblies operable between a first position and a second position in a wellbore; connecting a hydraulic control line to the piloted actuator tool assemblies; and controlling each of the piloted actuator tool assemblies by performing an actuation cycle. 
   Each of the piloted actuator tool assemblies is self-piloted in the sense that as the actuation cycles, or pressure cycles, are provided through the hydraulic line each tool assembly controls its own actuation sequence. An example of a piloted actuator tool assembly includes a flow control valve moveable from an open position to a closed position; and an actuator having a pilot assembly and a shuttle, the hydraulic control line in communication with the pilot assembly and the flow control valve through the shuttle, the shuttle selectively moveable by the pilot assembly in response to the actuation cycles to operate the flow control valve between the open and the closed position. 
   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. 1A  is a schematic of a wellbore having a multi-drop tool system of the present invention; 
       FIG. 1B  is a representation of an actuation sequence for each of the tool assemblies illustrated in  FIG. 1A ; 
       FIG. 2  is a schematic of a piloted actuator valve assembly; and 
       FIGS. 3A-3C  are illustrations of an actuator 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  illustrates a multi-drop tool system of the present invention, generally denoted by the numeral  10 , installed in a wellbore  12 . Wellbore  12  is commonly completed with casing  14 . In the illustrated example, wellbore  12  is completed through three zones of interest  16   a - 16   c  by providing perforations  18  through casing  14 . 
   Multi-drop tool system  10  includes multiple hydraulically operated tools  20 , multiple actuators  22 , and a hydraulic control line  24 . Hydraulic tools  20  are illustrated and described herein as flow control valves, however, it should be understood that any device that may be actuated from one position to another position may be utilized. For example, tools  20  include flow control valves, formation isolation valves, packers, perforating guns and the like. It is also noted that the tool be operatable between at least two positions, such as open, closed or choked for valves as well as various other operation positions of other tools  20 . 
   Hydraulic control line  24  extends from a control station  26 , typically positioned at the surface, which commonly includes a hydraulic fluid reservoir, pumps, and electronic control equipment. It is recognized that system  10  may comprise a single tool  20  and its corresponding actuator  22 , however the present invention is particularly adapted for multi-dropping, wherein multiple tools are connected to a single control line for operation. Actuators  22  are self-piloted actuators wherein each actuator may respond differently from another actuator in response to the same actuation cycle. 
   Valves  20  are positioned in wellbore  12  along a pipe string  28 . Pipe string  28  may be constructed of jointed pipe, coiled tubing or the like. Each of the valves  20  is operationally connected to the single hydraulic control line  24 . Each valve  20  is connected to control line  24  through a designated actuator  22 . Thus, there is one actuator  22  for each valve  20 , forming a piloted actuator valve assembly  30 . 
   Actuators  22  of the present invention facilitate the control and operation of multiple tools  20  from a single control line  24  as described below with reference to  FIG. 1B . It is noted that actuator  22  may be located in several locations such as in the annulus  32  between casing  14  and pipe string  28  as well as being incorporated into tool  20 . 
   Refer now to  FIG. 2 , wherein a schematic of a piloted actuator valve assembly  30  is shown in isolation. Assembly  30  includes a valve  20  and its corresponding piloted actuator  22 . Valve  20  may be operated from a closed position to an open position (shown) in which fluid may flow between annulus  32  and the bore  34  of valve  20 . Actuator  22  includes a pilot section  36  and a valve shuttle section  38 . A conduit or supply line  40  is connected between hydraulic control line  24  and actuator  22 . Supply line  40  is connected to valve  20  through valve shuttle section  38  to valve  20 . The hydraulic pressure and fluid from control line  24  is selectively provided to valve  20  through actuation of valve shuttle section  38  by pilot section  36 . A fluid return line  42  may be provided from valve  20  through valve shuttle section  38  for venting fluid to annulus  32  when moving valve  20  between positions. It should further be recognized that return line  42  may also serve as a supply line from actuator  22  to valve  20 , as such hydraulic pressure can be provided through line  40  or line  42 , each line actuating valve  20  to a different position. A vent line may be provided that returns to the surface or other location facilitating control of the back pressure an each actuator  22  and valve  20 . 
   A pilot line  44  is split off of supply line  40  upstream of actuator  22  and directed to pilot section  36 . Manipulation of the hydraulic pressure in control line  24  operates pilot section  36  which selectively actuates valve shuttle section  38 . Actuation of shuttle valve section  38  operates valve  20  between its various positions. 
   Refer now to  FIGS. 3A through 3C  wherein exploded views of actuator  22  are shown during various steps of operation. Actuator  22  includes pilot section  36  and valve shuttle section  38 . Shuttle section  38  is illustrated and described herein as a two position shuttle valve mechanism. Shuttle section  38  includes a shuttle  46  moveable along a chamber  48  formed by a housing  50 . A power supply port  52  is formed through housing  50  and in fluid connection with supply line  40  and control line  24  ( FIG. 2 ). 
   Function ports  54  and  56  are formed through housing  50  and are in fluid and operational communication with valve  20 . Each port serves to actuate valve  20  to a position or function when hydraulic pressure is supplied through the function port. A vent port  55  is provided through housing  50  to vent pressure and fluid as illustrated schematically in  FIGS. 3A-3B . 
   Ports  54  and  56  are in fluid communication with valve  20 . Shuttle  46  is moveable along chamber  48  to selectively provide fluid communication between supply port  52  and either of the function ports  54  or  56 . By example, supplying hydraulic pressure through supply port  52  to first function port  54  operates valve  20  to the open position and providing hydraulic pressure through supply port  52  to second function port  56  operates valve  20  to the closed position. 
   Pilot section  36  is of a unique design providing functionality to shuttle valve section  38  that facilitates multi-dropping a plurality of tools  20  from a single hydraulic control line. Pilot section  36  includes a pilot assembly  29  in operational connection with shuttle valve  46 . The pilot assembly includes a piston  58 , biasing mechanism  60 , and an indexer head  62  carrying a pushpin  76 , and sequencing pattern consisting of track  72  and finger  74 . The pilot assembly is mounted within housing or body  50  which includes a pilot port  64  that is in pressure communication with pilot line  44 . 
   Piston  58  has a first end  58   a  and a head end  58   b . First end  58   a  is disposed so as to be in operational and responsive communication with port  64  and the pressure provided from pilot line  44 . Indexer head  62  is connected to head end  58   b . Biasing mechanism  60 , for example a spring, is connected to piston  58  so as to bias piston  58  in the opposite direction from the direction that it is urged by pressure through pilot port  64 . 
   Indexer head  62  includes a circumferential, outer surface  68  and a front face  70 . Grooves  72  are formed on surface  68  to mesh with a finger  74 . It is noted that finger  74  may extend from head  62  and mate with grooves  72  formed by body  50 . As known in the art, grooves  72  and finger  74  may comprise detents, ridges and other mechanisms known for creating a pattern of movement. Grooves  72  and finger  74  are understood to be, and are referred to herein, as an indexing mechanism. 
   A pushpin  76  extends outwardly from face  70  of indexer head  62  for selectively connecting with linkage mechanism  78 . Linkage mechanism  78  includes a first end  80 , such as a shaft, connected to shuttle element  46 . The second end of linkage mechanism  78  includes a pair of contact ends  82   a  and  82   b . For actuation of valve  20 , pushpin  76  is urged into contact with one or the other of ends  82 . Movement of the contact ends  82  results in shuttle  46  moving to the next function port. Shuttle valve  46  is moved in a first direction when contact end  82   a  is acted on and moves in a second opposite direction when contact end  82   b  is actuated. 
   Operation of multi-drop tool system  10  and actuator  22  is now described with reference to  FIGS. 1 through 3 . Wellbore  12  is completed with a pipe string  28  carrying three piloted actuator tool assemblies, designated as  30   a ,  30   b , and  30   c . A single hydraulic line  24  interconnects the assemblies  30  to control station  26 . 
   In the initial position, run-in position, valves  20   a ,  20   b ,  20   c  may be in the closed position as shown in  FIG. 1B . It is noted that the valves do not have to be in the same initial position. In the first operational step, also referred to as the pressure-up step, pressure is applied from control station  26  through control line  24 . Pressure and fluid are provided from control line  24  to supply line  40  and pilot port  64  through pilot line  44 . Pilot piston  58  moves laterally toward linkage  78  in response to the pressure at pilot port  64 , compressing biasing mechanism  60 . In this example, pushpin  76  contacts end  82   a  of linkage  78  causing shuttle element  46  to move from a first position port  54  to the second position port  56  ( FIGS. 3A and 3B ). In the example of  FIG. 1B  for valve  20   a , movement of shuttle  46  causes valve  20  to be operated from the closed position to the open position. It should be noted that pushpin  76  and indexer head  62  may be oriented so that pushpin  76  does not contact linkage end  82  on specified pressure up steps as described in more detail below. 
   In a next operational step, the bleed-down or bleed-off pressure step, pressure is bled off of pilot port  64  and biasing mechanism  60  urges piston  58  back to its initial position. As piston  58  moves laterally to its initial position indexer head  62  rotates due to interaction of finger  74  in grooves  72 . In this illustration, rotation of indexer head  62  positions pushpin  76  out of alignment with ends  82  of linkage  78 . Thus, in the next pressure-up step the lateral movement of pushpin  76  will fail to contact either of ends  82  thereby not actuating shuttle  46  or valve  20  to the next position. Thus, actuation of valve  20  is skipped. The rotation of indexer head  62  may be individually programmed in the configuration of grooves  72 , or the number of pushpins  76 , to create various actuation sequences such as those represented by  FIG. 1B . 
   Referring to  FIGS. 1A and 1B  in particular, each of the actuators  22   a ,  22   b ,  22   c  is programmed to have a particular actuation sequence for its corresponding valve. The actuation sequence is programmed by forming grooves  72  (or a track) or by varying the number of pushpins  76  in a manner such that actuation of shuttle  46  and valve  20  occurs on desired cycles. A cycle includes a step of pressuring up, causing indexer head  62  and pushpin  76  to move laterally toward linkage  78  and bleeding the pressure off causing indexer head  62  and pushpin  76  to both move laterally away from linkage  78  and to rotate. 
   Referring specifically to  FIG. 1B , each valve assembly  30  ( FIG. 1A ) has a different actuation sequence. For example, assembly  30   a  is programmed such that valve  20   a  is actuated between the open and closed position on each cycle. Assembly  30   b  is programmed so that valve  20   b  skips actuation every other cycle. Thus, valve  20   b  is actuated between positions on every other cycle. Assembly  30   c  is programmed so that it skips actuation in three of every four cycles. It is noted that although the various examples indicate movement between open and closed positions, movement may be between various positions which for valves may be open, closed or choked positions. 
   From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a system for hydraulically controlling and operating multiple wellbore tools from as single hydraulic control line 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.