Abstract:
An apparatus ( 100 ) for actuating a hydraulically controllable device ( 102 ) disposed in a wellbore is disclosed. The apparatus (100) comprises a downhole hydraulic fluid source ( 134 ), a hydraulic fluid passageway ( 136 ) providing a communication path between the downhole hydraulic fluid source ( 134 ) and the hydraulically controllable device ( 102 ), a valve ( 144 ) disposed within the hydraulic fluid passageway ( 136 ) and a downhole electronics package ( 138 ). The downhole electronics package ( 138 ) receives a signal from the surface to operate the valve ( 144 ) from the closed position to the open position such that hydraulic pressure from the downhole hydraulic fluid source ( 134 ) actuates the hydraulically controllable device ( 102 ).

Description:
TECHNICAL FIELD OF THE INVENTION 
     This invention relates general to the field of actuating hydraulically controllable downhole tools and, in particular to, a remotely operated service tool having a self-contained hydraulic system for actuating hydraulically controllable downhole tools disposed within a wellbore. 
     BACKGROUND OF THE INVENTION 
     Without limiting the scope of the invention, its background is described in connection with setting a packer assembly in a wellbore that traverses a hydrocarbon formation, as an example. 
     Heretofore in this field, during the treatment and preparation of the wellbore for production, a packer assembly and sand control screen along with a service tool are run into the wellbore on a work string. The setting of the packer assembly against the casing is typically accomplished by manipulating the service tool. The success of such operations is dependent upon the ability to reciprocate the service tool vertically or to rotate it relative to the packer assembly. It has been found, however, that rotational displacement of the service tool in deviated wells is difficult to perform reliably because of frictional binding between the work string and the casing. Accordingly, vertical reciprocal movements have been preferred for setting and releasing packer assemblies in such instances. 
     During run-in, the packer assembly is mechanically locked in the unset condition by shear pins and anti-preset lugs that support the weight of the packer assembly along with the hang weight of other components such as a swivel shear sub, blank pipe, a sand control screen, a polished nipple, a tail screen, and a packer assembly. The shear pins and anti-preset lugs can safely support the combined weight of the downhole equipment. The shear pins are rated to yield to a preset shearing force to separate and release the service tool after the packer assembly has been set. It has been found, however, that in deviated or otherwise obstructed wellbores, shear pins designed to shear in response to vertical reciprocation may be damaged and the packer assembly may sometimes be inadvertently preset in response to frictional loading between the packer assembly and the wellbore in tight spots. 
     It has also been found that when operating in slanted or deviated wellbores, it is sometimes difficult to transmit sufficient force downhole from the surface to set mechanically actuated packer assemblies. The frictional engagement between the wellbore and the work string interferes with the transmission of the necessary mechanical force to set the packer assembly. 
     To overcome these difficulties, pressure may be applied to the fluid column within the work string to transmit the required packer assembly setting force. For example, the packer assembly may be set by dropping a ball through the work string into the service tool. Pressurized fluid is then pumped down the work string to shear the shear pins, thereby setting the packer assembly. During gravel packing or frac packing operations, it is desirable to remove the ball from the service tool. It has been found, however, that in slanted or deviated wellbores or in tapered work strings it is difficult to reverse the ball out of the work string. In addition, it has been found that the ball, in certain installation, may damage downhole equipment when it is run-in the service tools. 
     Therefore a need has arisen for an improved service tool for running and setting a packer assembly in a wellbore. A need has also arisen for an improved service tool for setting a packer assembly without the need for translational or rotational movement of the service tool with respect to the packer assembly and without the need for running a ball into the service tool. A need has further arisen for such a service tool that can set a packer assembly in a deviated or slanted wellbore. 
     SUMMARY OF THE INVENTION 
     The present invention disclosed herein comprises a service tool for hydraulically actuating a downhole device from a remote location. The service tool utilizes hydraulic pressure for actuating the downhole device without the need for translational or rotational movement of the service tool and without the need for running a ball into the service tool. The service tool of the present invention may be used in any wellbore including a deviated or slanted wellbore. 
     The service tool of the present invention comprises a downhole hydraulic fluid source, a hydraulic fluid passageway that provides a communication path between the downhole hydraulic fluid source and the hydraulically controllable device, a valve disposed within the hydraulic fluid passageway and a downhole electronics package. The downhole electronics package receives a signal from a surface installation to operate the valve from the closed position to the open position, thereby transmitting hydraulic pressure from the downhole hydraulic fluid source to the hydraulically controllable device and actuating the hydraulically controllable device. 
     The hydraulic fluid source includes a housing and a sleeve that define a hydraulic fluid chamber therebetween having hydraulic fluid contained therein. The sleeve is slidably disposed about the housing and has first and second positions relative to the housing. The sleeve is operated from the first position to the second position, responsive to hydrostatic pressure, once the valve is operated from the closed position to the open position. The sleeve and the housing also define an atmospheric air chamber therebetween having air contained therein. 
     The downhole electronics package includes a transducer that receives the signal from a surface installation. The transducer may be selected from a variety of transducers that are suitable for downhole reception of a signal including, but not limited to, an acoustic transducer, a pressure pulse transducer, an electromagnetic transducer and the like. The transducer receives the signal and relays the signal to the controller of the valve. The downhole electronics package also includes a battery pack to provide a source of electrical power. 
     The method for actuating a downhole device of the present invention involves sending a signal to a downhole electronics package, transmitting hydraulic pressure from a downhole hydraulic source to the downhole device in response to the signal and actuating the downhole device in response to the hydraulic pressure. The method may also include operating a valve to establish a communication path between the downhole hydraulic source and the downhole device and utilizing hydrostatic pressure to transmit the hydraulic fluid from the downhole hydraulic source to the downhole device. 
     In the method of the present invention, the signal may be sent to a downhole electronics package from a surface installation. The signal may be an acoustic signal, a pressure pulse signal, an electromagnetic signal or other suitable signal the may be received downhole. 
     The actuation of the downhole device may further include the setting a downhole device such as a packer assembly, or the manipulating a downhole device such as a sliding sleeve, a fluid control device or a well control device. Additionally, the actuation of the downhole device may be achieved by axially shifting a component of the downhole device or rotatably operating a component of the downhole device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the features and advantages of the present invention, references now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which: 
     FIG. 1 is a schematic illustration of an offshore oil and gas platform operating a service tool of the present invention; 
     FIGS. 2A-2F are quarter-section views of a service tool of the present invention in the run-in position that is attached to a packer assembly in the unset position; and 
     FIGS. 3A-3F are quarter-section views of a service tool of the present invention after operation of the service tool and actuation of a packer assembly to the set position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the making and using of various embodiments of the present invention is discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention. 
     Referring to FIG. 1, a service tool operably coupled to a packer assembly in use with an offshore oil and gas platform is schematically illustrated and generally designated  10 . A semi-submersible platform  12  is centered over a submerged oil and gas formation  14  located below sea floor  16 . A well  18  extends through the sea  20  penetrating sea floor  16  to form wellbore  22  which traverses various earth strata. 
     Platform  12  has hoisting apparatus  24  and a derrick  26  for raising and lowering pipe strings such as work string  28 . Attached to the lower end of work string  28  is service tool  30  that is landed within the bore of packer assembly  32 . As will be explained in greater detail below, packer assembly  32  has mechanically actuated slips which set expandable annular seal elements  34  against the inside bore of tubular well casing  36 . Packer assembly  32  is actuated by hydraulic fluid from service tool  30 . Service tool  30  is remotely operated by a signal generated at surface installation  38 . After setting packer assembly  32 , service tool  30  remains sealed against the inner bore of packer assembly  32  to, for example, allow a gravel laden slurry to be pumped through the work string  28  and the service tool  30  into annulus  40  between the casing  36  and a sand control screen  42 . A seal is provided above and below formation  14  by expanded annular seal elements  34  carried on packer assembly  32  and expanded annular seal elements  44  carried on packer assembly  46 . During the gravel pack operation, the annulus  40  is filled with slurry, and the slurry is pumped through perforations  48  formed in the sidewall of the well casing  36  into the surrounding formation  14 . 
     Even though FIG. 1 depicts a cased vertical well, it should be noted by one skilled in the art that the service tool of the present invention is equally well-suited for operation in uncased wells, deviated wells, inclined wells or horizontal wells. 
     Referring now to FIGS. 2A-2F, the service tool  100  of the present invention is rigidly locked onto packer assembly  102  during the initial run-in operation. According to this arrangement, the service tool  100 , packer assembly  102  and all the equipment which is hung off of packer assembly  102  are run-in through the bore of casing  36  as an assembled unit. As best seen in FIG. 2E, a group of separation shear pins  104  having appropriate shear strength for supporting the packer assembly hang weight connect the packer assembly mandrel  106  to the service tool mandrel  108 . The shear pins  104  are rated to safely support the combined weight of the downhole equipment, and are rated to yield to a preset shearing force to separate and release the service tool  100  from the packer assembly  102  after setting packer assembly  102 . 
     Referring specifically to FIG. 2A, service tool  100  includes a hydraulic power unit  110 . Hydraulic power unit  110  has an inner mandrel  112 . Disposed about inner mandrel  112  is an air chamber piston  114  and an air chamber sleeve  116 . Disposed between air chamber sleeve  116  and inner mandrel  112  is air chamber  118 . Also disposed about inner mandrel  112  is a retainer member  120 . Between retainer member  120  and air chamber piston  114  is an annular housing extension  122  having a port  124  therein. Air chamber sleeve  116  includes a port  125 . Disposed about inner mandrel  112  is a retainer member  126 . Atmospheric air may be contained within air chamber  118 . 
     Below air chamber  118  and disposed about inner mandrel  112  is a hydraulic piston  128 , a hydraulic sleeve  130  and a retainer member  132 . Disposed between hydraulic sleeve  130  and inner mandrel  112  is a hydraulic fluid chamber  134  that contains hydraulic fluid. Disposed between retainer member  132  and inner mandrel  112  is a hydraulic fluid passageway  136 . 
     Referring now to FIG. 2B, a control assembly  138  is disposed about inner mandrel  112 . Control assembly  138  includes a battery pack  140  that provides electrical power to a transducer  142 . Transducer  142  receives signals from surface installation  38  of FIG. 1 in the form of acoustic signals, electromagnetic signals, pressure pulse signals or other suitable signals that may transmit information from a remote location to transducer  142 , such methods being well-known to those skilled in the art. Disposed within hydraulic fluid passageway  136  is a valve  144  that may be operated responsive to signals received by transducer  142 . 
     Referring now to FIGS. 2C-2D, at the lower end of inner mandrel  112  is a connector member  146  that is threadably attached to a connector member  148 . Threadably and sealably connected to connector member  148  is outer housing  150 . Outer housing  150  includes the lower end of hydraulic fluid passageway  136 . The upper portion of service tool mandrel  108  extends into outer housing  150 . Outer housing  150  includes an outer housing extension  152 . Disposed between outer housing extension  152  and service tool mandrel  108  is operating piston  154  which includes an operating piston extension  156 . The relative movement of operating piston extension  156  and service tool mandrel  108  is prevented by shear pins  184  as best seen in FIG.  2 E. 
     Below operating piston extension  156  is a transfer support assembly  158  that includes a group of anti-preset lugs  160  carried by a collet  162 . Anti-preset lugs  160  are engaged against the lower shoulder of annular flange  164  which is formed on a tube guide extension  166 . Setting sleeve extension  166  is aligned to receive sleeve  168 . The hang weight of packer assembly  102  is transmitted through a setting sleeve  170  through the anti-preset lugs  160  and collet  162  to service tool mandrel  108 . As such, packer assembly  102  and the equipment attached thereto are supported by the work string  28  through service tool mandrel  108 , anti-preset lugs  160  and setting sleeve  170 . This configuration results in a decoupling of handling forces which arise during the run-in procedure with respect to shear pins  104 . 
     The service tool  100  is provided with a locking flange  172  which is engaged by a shoulder portion  174  of the collet  160 . Collet  160  is held in its position shown in FIG. 2E by its finger portions  176  having their head portions  178  received in a detent groove  180  formed in the service tool mandrel  108  above the upper shoulder of the locking flange  172 . The head portion  178  is engaged and prevented from deflecting by a piston shoulder  182  which forms a part of operating piston extension  156 . 
     As best seen in FIGS. 2E-2F, connected to the lower end of setting sleeve  170  is connector sub  186 . Disposed between connector sub  186  and packer assembly mandrel  106  is a slip ring assembly  188  that is used to retain the seal element  190  and casing slips  192  of packer assembly  102  in the set position. 
     It should be apparent to those skilled in the art that the use of directional terms such as above, below, upper, lower, upward, downward, etc. are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being towards the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure. It is to be understood that the downhole components described herein, for example, service tool  100 , may be operated in vertical, horizontal, inverted or inclined orientations without deviating from the principles of the present invention. 
     The operation of service tool  100  and packer assembly  102  will now be described with reference to FIGS. 3A-3F, wherein service tool  100  and packer assembly  102  are shown following their operation. Transducer  42  receives a signal from surface installation  38  to initiate the actuation of a hydraulically controllable device such as packer assembly  102 . Transducer  142  converts the signal to an electrical signal that is used to open valve  144 , as best seen in FIG.  3 B. Once valve  144  is open, the hydrostatic pressure within annulus  40  downwardly biases air chamber piston  114 , air chamber sleeve  116 , hydraulic piston  128  and hydraulic sleeve  130 , as best seen in FIG.  3 A. The air in air chamber  118  upwardly biases air chamber piston  114  to dampen the downward bias force of the hydraulic pressure, thereby reducing the downward velocity of the chamber piston  114 , air chamber  116 , hydraulic piston  128  and hydraulic sleeve  130 . The hydraulic fluid in hydraulic chamber  134  may now pass through hydraulic fluid passageway  136  and valve  144 . As best seen in FIG. 3D, the hydraulic fluid downwardly biases operating piston  154  including operating piston extension  156  and accumulates in hydraulic fluid reservoir  194 . 
     Operating piston  154  is guided for movement along the external surface of the service tool mandrel  108  by outer housing extension  152 . Once the hydraulic pressure is increased to a level great enough to cause shear pins  184  to shear, operating piston  154  is permitted to drive sleeve  168  downwardly against annular flange  164  of setting sleeve extension  166  as best seen in FIG.  3 E. Collet  162  remains in place as operating piston  154  is driven downwardly until shoulder  182  clears head portions  178 , thereby permitting it to deflect and also permitting transfer support assembly  158  to move downwardly along the locking flange  172 . Thereafter, the spring loaded anti-preset lugs  160  retract radially inwardly. When this occurs, the hang weight of packer assembly  102  is transferred from anti-preset lugs  160  to shear pins  104 . 
     Setting sleeve  170  is movable relative to packer assembly mandrel  106 . Setting sleeve  170  is moved downwardly relative to packer assembly mandrel  106  in response to continued extension of operating piston  154 . As operating piston  154  nears the limit of its extension along service tool mandrel  108 , slips  192  are engaged and set against the inside bore of the well casing  36  as best seen in FIG.  3 F. 
     Because the packer assembly mandrel  106  is anchored onto the service tool mandrel  108  by separation shear pins  104 , setting sleeve  170  continues its downward movement relative to packer assembly mandrel  106 . Once the desired slip setting pressure has been achieved and packer assembly  102  is securely anchored in place, service tool  100  can then be released from the packer assembly  102  by pulling the work string  28  upward. Additionally, prior to pulling work string  28  and service tool  100  out of wellbore  22  a formation conditioning or sand control operation may be preformed such as a high rate water pack, a frac pack, a gravel pack or the like. 
     According to the foregoing arrangement, service tool  100  attaches to packer assembly  102  in such a way that packer assembly  102  can be run, set and service tool  100  released from packer assembly  102  without any kind of rotation of service tool  100 . The hang load is transferred from the separation shear pins  104  by the anti-preset lugs  160 . Accordingly, any weight hanging below packer assembly  102  is not applied to separation shear pins  104  during the run-in procedure. Anti-preset lugs  106  are locked in the supporting position during transit by the set of shear pins  184  which lock operating piston extension  156  to service tool mandrel  108 . Movement of operating piston  154  in response to the transfer of hydraulic fluid from hydraulic fluid chamber  134  through hydraulic fluid passageway  136  into hydraulic fluid reservoir  194  causes pins  184  to shear, such that collet  162 , which holds anti-preset lugs  160  in place, becomes unsupported, thereby permitting collet  162  to carry anti-preset lugs  160  to a new position which permits anti-preset lugs  160  to retract, thereby transferring the hang weight to separation shear pins  104 . 
     Continued movement of operating piston  154  downwardly brings sleeve  168  of service tool  100  to bear against setting sleeve extension  166  of packer assembly  102 , thereby moving the outer parts of packer assembly  102  relative to packer assembly mandrel  106 , and in doing so, expanding seal elements  190  and setting slips  192 . After slips  192  have been securely set and annular seal elements  190  have been expanded, separation pins  104  are sheared. Movement of service tool  100  is then possible by straight up or down movement of work string  28  at the surface. 
     As a result, the unique service tool  100  of the present invention provides for remote actuation of a hydraulically controllable device such as packer assembly  102 . Remote actuation is achieved utilizing surface installation  38  to generate a signal that is received by transducer  136  of hydraulic power unit  110 . This allows for the highly reliable use of hydraulic fluid transfer to operate the hydraulically controllable device without axial or rotational reciprocation of service tool  100  and without the need to drop a ball down through work string  22  or run a hydraulic line from the surface. 
     Even though the service tool of the present invention has been described with reference to operating packer assembly  102  using hydraulic power unit  110  to axially shift operating piston  154 , among other components, it should be noted by one skilled in the art that the service tool of the present invention is equally well-suited for actuating other hydraulically controllable downhole devices. For example, the service tool of the present invention may be used to rotatably operate components in a downhole device in order to achieve a desired result. Similarly, the service tool of the present invention may be used to hydraulically initiate the actuation of a valve from either the closed position to the open position or the open position to the closed position, to hydraulically initiate the shifting of a sliding sleeve or to hydraulically initiate the actuation of similarly operated downhole devices. 
     While this invention has been described with a reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.