Abstract:
A releasable packer has a control line therethrough. A hydraulic release mechanism of the packer is controlled from the surface by application of flow and pressure. A modification of the packer and release mechanism using resettable collets and return springs allows multiple sets and releases of the packer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims the priority of provisional application No. 60/139,708, filed on Jun. 17, 1999 and entitled Well Packer and Method. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of downhole tools. More specifically, the invention relates to a device and method for directing bypass lines through a packer and for releasing a packer using flow through at least one of the bypass lines. 
     BACKGROUND OF THE INVENTION 
     Completion systems require or may require control lines and telemetering lines that may be either electric, hydraulic, or fiber optic. Using the control lines, various tools may be set or unset, gauges and other equipment may be powered, monitored, and controlled, and other actions may be performed using the control lines. 
     Well completions typically include a casing extending from a surface wellhead to the producing formation, a production tubing located within the casing, and one or more other completion devices. One such completion device is commonly called a packer and is used to block, pack off, and seal the annulus formed between the casing and the production tubing. Placement of one or more packers in this way directs the production fluid into the production tubing. Packers are also used for other purposes, such as during cementing, gravel packing, and during other procedures. 
     However, the packer presents an obstacle to the control and telemetering lines and the like (commonly referred to herein as “control lines”), because the control lines are typically run between the tubing and the casing. Accordingly, there is a need for a bypass through the packer to allow communication of the control lines through the packer. 
     Often, there is a need for a packer that may be set and, at some later time, released. In some cases, it may be necessary to place multiple, spaced packers in a well in which the packers are all set and subsequently released. Typically, the release of such packers is accomplished by pulling the tubing for release or using other mechanical release devices. However, such release devices may inadvertently release by inadvertent pulls on the tubing. Further, there is also a need for packers that may be set and released a plurality of times. 
     There remains a need for a packer that may be set and unset using, for example, hydraulic means and that provides communication and protection for control lines through the packer. 
     SUMMARY OF THE INVENTION 
     The present invention features a hydraulically releasable well packer that has a plurality of bypass passages to allow control lines to pass therethrough. The present invention also provides a release mechanism that is actuated by hydraulic fluid to effect the release of the packer slips and elements. According to another exemplary embodiment, the present invention features a release mechanism that can be reset to allow the repositioning and resetting of the packer in the well with the possibility of subsequent release of the packer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The manner in which these objectives and other desirable characteristics can be obtained is explained in the following description and attached drawings in which: 
     FIGS. 1A-D are cross sectional, side elevational views of the present invention; 
     FIG. 2 is a cross sectional view of the present invention taken along lines A—A in FIG. 1A; 
     FIG. 3 is a cross sectional view of the present invention taken along lines B—B in FIG. 1B; 
     FIG. 4 is a cross sectional view of the present invention taken along lines C—C in FIG. 1B; 
     FIG. 5 is a cross sectional, side elevational view of the release mechanism in the open position; 
     FIG. 6 is a cross sectional, side elevational view of the release mechanism in the closed, released position; 
     FIG. 7 is a cross sectional, side elevational view of an alternative embodiment for the release mechanism in the closed, released position; and 
     FIG. 8 is a cross sectional, side elevational view of an alternative embodiment for the release mechanism in the open position. 
    
    
     It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention generally provides a releasable well packer  10  having at least one bypass line  12  through the mandrel. The packer  10  preferably includes a release mechanism  14  (see FIGS. 5-8) actuated by applied fluid flow and pressure through a control line  18  extending from the surface and communicating with the packer  10 . In an alternative embodiment, the packer  10  is adapted for multiple setting and multiple releasing of the slips  40  and elements  34 . 
     FIGS. 1A-D illustrate a first embodiment of the well packer  10  illustrated in four sections extending from the section illustrated in FIG. 1A to the section illustrated in FIG.  1 D. The body  20  of the packer  10  is generally formed of an upper mandrel  22  that is releasably, slideably interconnected to a releasing sleeve  24  and a lower mandrel  26 . The body  20  defines a passageway  28  therethrough that is adapted for coaxial alignment with and fluid communication with a tubing string and includes standard connections for attachment to the tubing string to provide fluid communication therethrough. The upper mandrel  22  is formed of a first upper mandrel component  30  and a second upper mandrel component  32 . The first and second upper mandrel components  30 ,  32  are fixedly attached to one another and are hereinafter referred to collectively as the upper mandrel  22 . 
     Similarly, the lower mandrel  26  is formed of four generally interconnected and associated components that do not move relative to one another. For clarity and ease of description these components are collectively referred to herein as the lower mandrel  26 . Likewise, the upper mandrel  22 , lower mandrel  26 , and releasing sleeve  24  are collectively referred to herein as the body or mandrel  20 . In general, the upper mandrel  22 , lower mandrel  26 , and releasing sleeve  24  are releasably attached to one another and do not move relative to one another until the desired release of slips  40  and element  34  of the packer  10 . 
     At least one sealing element  34  is disposed about the upper mandrel  22 . The upper position of the sealing elements  34  are established by a shoulder member  36  fixed to the upper mandrel  22 . The lower end of the elements  34  abut an element actuator  38  slideably mounted to the upper mandrel  22 . A plurality of slips  40  are spaced circumferentially about the upper mandrel  22  at a position below the elements  34  and are secured thereto by a slip cage  42 , or other known devices. Slip actuators  44  are slideably mounted to the upper mandrel  22  on either or both longitudinal sides of the slips  40 . Actuators  44  have a ramp surface  46  facing cooperating ramp members  48  of the slips  40  to selectively move the slips  40  radially relative to the mandrel between an inwardly retracted running position and an outwardly extended set position. 
     Shear pins  50  connect the lower slip actuator  44  to the upper mandrel  22  and the slip cage  42  to the upper and lower slip actuators  44  to prevent the relative movement of the slip actuators  44  and the slip cage  42  to the upper mandrel  22 , and to prevent movement of the slips  40  to the outwardly extended position until the occurrence of a predetermined event shearing the shear pins  50 . The upper slip actuator  44  is fixedly attached to the element actuator  38 . Thus, the element actuator  38  is also held in position relative to the upper mandrel  22  and the elements  34  until the setting of the element  34  is desired. Note that the elements  34  and slips  40 , their positioning, and their general actuation as described are matters of preference and should not be limiting, as other variations are known, e.g., to position the slips  40  in a different orientation relative to the elements  34 . 
     A setting piston  52  is slideably positioned within the mandrel has an upper end abutting the lower end of the lower slip actuator  44 . A setting port  54  provides fluid communication from the passageway  28  through the mandrel to a lower end of the piston. Seals  56  between the setting piston  52  and the mandrel facilitate actuation of the setting piston  52  in response to pressure applied through the tubing, into the passageway  28 , through the setting port  54 , and to the bottom of the setting piston  52 . A locking member  60 , preferably comprising cooperating wicker threads  62 , restricts the motion of the piston to unidirectional movement in the setting direction (which is upward in the disclosed embodiment). In the disclosed embodiment, the locking member  60  includes a set of wicker threads  62  attached to the setting piston  52  and a cooperating set of wicker threads  62  attached to the lower mandrel  26 . 
     Accordingly, to set the packer  10 , sufficient pressure is applied through the tubing and the setting port  54  to the bottom of the setting piston  52  to shear the shear pins  50  holding the slip actuators  44  to the mandrel and the slip cage  42 . The setting piston  52  moves upwardly in response to the pressure abutting the lower slip actuator  44  forcing it into the slips  40 . The upward force and motion is transmitted to the upper slip actuator  44  which moves upward moving the element actuator  38  upward. The movement of the slip and element actuators  38 ,  44  forces the slips  40  into the extended set position and compresses the elements  34  creating a seal between the packer  10  and the well casing. The upward motion of the components is locked in by the locking member  60 . 
     A portion of the upper mandrel  22  extends into the lower mandrel  26 . A set of bolts  64 , or detents, attached to the upper mandrel  22  cooperate with mating slots  66  in the lower . mandrel  26  to maintain their relative rotational orientation. The upper mandrel  22  is releasably connected to the releasing sleeve  24  by a shear pin  68 . The upper mandrel  22  is generally releasably connected to the lower mandrel  26  by a set of locking dogs  70  with gripper teeth  72  that mate with gripper teeth  72  on an inner surface  74  of the lower mandrel  26 . The locking dogs  70  have an inner surface  76  abutting an outer surface  78  of the releasing sleeve  24 . Mating profiles  80 ,  82  on the inner surface  76  of the dogs  70  and the outer surface  78  of the releasing sleeve  24  allow selective disengagement of the gripper teeth  72  holding the lower mandrel  2640  the locking dog and, thereby the sleeve and upper mandrel  22 . In a first, set position of the releasing sleeve  24 , wherein the shear pin  68  is intact, the profiles  80 ,  82  of the locking dogs  70  and the lower mandrel  26  are misaligned to maintain the engagement of the gripper teeth  72  and the relative axial positions of the lower mandrel  26  to the releasing sleeve  24  and the upper mandrel  22 . 
     Conventionally, to release the packer  10 , a tool is run into the passageway  28  and locked into a profile  88  formed in the releasing sleeve  24 . The releasing sleeve  24  is then mechanically lifted shearing the shear pin  68  connecting the releasing sleeve  24  to the upper mandrel  22 . Further upward movement of the releasing sleeve  24  aligns the profiles  80 ,  82  of the releasing sleeve  24  and the locking dogs  70  allowing the locking dogs  70  to move inwardly away from the lower mandrel  26 . Once released, the lower mandrel  26  along with the setting piston  52  connected thereto are free to move downward relative to the upper mandrel  22  releasing the pressure holding the slips  40  and the elements  34  in the set position. The elements  34  and slips  40  are then free to return to the released, retracted position. According to a preferred embodiment of the present invention, hydraulic release mechanism  14  is mounted to selectively force releasing sleeve  24  upward, thus avoiding inadvertent release due to lifting of releasing sleeve  24  (see FIGS.  5 - 8 ). 
     FIGS. 2 through 4 are cross sectional views of the packer  10  shown in FIG.  1 . In the embodiment shown, the passageway  28  through the mandrel is eccentrically positioned so that the mandrel wall is thicker to one side. One or more bypass lines  12  may then be easily provided through the packer  10  to facilitate the passage of control lines  18  therethrough (see FIG.  4 ). The eccentric design also facilitates alignment with other eccentric downhole tools in the completion string. As shown in FIG. 1, the bypass lines  12  may include a bypass line tubing  84  within the mandrel extending between the upper mandrel  22  and the lower mandrel  26  to provide a sealed passageway therethrough that allows fluid communication through the bypass line  12 , pressure transmission through the bypass line  12 , and that provides a protected passageway for control lines  18  extending therethrough. Fittings  86  at the top and bottom of the bypass lines  12  may be used to seal the bypass lines  12 . In an alternative embodiment, the passageway  28  is positioned concentrically through the mandrel. 
     FIG. 5 illustrates a preferred embodiment of a hydraulic release mechanism  14  mounted within the lower mandrel  26  that has a releasing piston  90  adapted to actuate the upward releasing motion of the releasing sleeve  24  in response to pressure and flow. For clarity, the figure shows a blown-up version of the release mechanism  14  with a schematic drawing of the interconnecting communication lines. In general, the release mechanism  14  provides a flow responsive valve  92  fixed in an open position by shear pins  94  and closeable by application of flow and pressure. A bleed-off line  96  communicating with the valve prevents the build-up of pressure in the release mechanism  14  when the flow responsive valve  92  is open. When the flow responsive valve  92  is closed, the pressure bleed-off line  96  is closed and pressure may build in the release mechanism  14 . The pressure actuates a releasing piston  90  by moving the piston  90  upward and forcing the releasing sleeve  24  up into the released position. The upward movement of the releasing sleeve  24  causes a release of the slips  40  and elements  34  as previously described. A detailed description of the release mechanism  14  follows. 
     The lower mandrel  26  defines a cylindrical release mechanism cavity  98  therein that is axially aligned with one of the bypass lines  12  through the packer  10 . A control line  18  communicates a control fluid to the release mechanism cavity  98  from a controllable source of fluid  102 , such as a pump, preferably located at the surface. Preferably, the release mechanism  14  incorporates an accumulator  104  in the control line  18  to enhance the response of the release mechanism  14  to flow conditions provided from the controllable source of fluid  102 . 
     The flow responsive valve  92  includes a valve cap  106  fixed within the release mechanism cavity  98 . An upper portion of a valve piston  108  is sealably positioned within the valve cap  106  and is releasably attached thereto by shear pins  94 . The control line  18  extends through the valve cap  106  and into a valve bore  110  defined through the valve piston  108 . The valve bore  110  has an enlarged upper portion  112  and a lower portion  114  having a relatively smaller diameter than the upper portion. The change in diameter between the upper portion  112  and the lower portion  114  defines a ball seat  116 . A valve ball  118  maintained within the enlarged upper portion  112  of the valve bore  110  has a lower specific gravity than the fluid in the control line  18 . Thus, the valve ball  118  floats above the ball seat  116 . Further, the diameter of the ball valve is smaller than the diameter of the upper portion  112 , but larger than the diameter of the lower portion  114 . Therefore, the position of the ball seat  116  is unaffected by pressure in the control line  18  and generally remains off seat. A flow of fluid through the control line  18 , however, will act to force the valve ball  118  downward onto the ball seat  116 . 
     A bleed-off line  96  communicates with the release mechanism cavity  98  at a position below the valve piston  108 . The opposite end of the bleed-off line  96  communicates with the annulus formed between the tubing and the casing with the bleed-off line  96  preferably extending through a separate bypass line  12  through the packer  10  so that the pressure vents above the packer  10 . A check valve  120  in the bleed-off line  96  allows flow from the release mechanism cavity  98  through the bleed-off line  96  only. Therefore, pressure buildup within the release mechanism  14  flows through the flow responsive valve  92  and through the bleed-off line  96  into the annulus of the well. By releasing the pressure within the release mechanism  14 , the actuation of the release mechanism  14  based upon pressure alone is prevented. Requiring flow in addition to pressure prevents unsetting of the packer  10  due to inadvertent pressure increases in the control line  18 . For example, if a surface valve in the control line  18  were inadvertently closed and the control fluid in the control line  18  expanded due to thermal increases, the pressure in the control line  18  would tend to rise. However, the bleed-off line  96  prevents such a situation from releasing the packer  10 . 
     When a flow of fluid is directed through the control line  18 , the valve ball  118  engages the valve seat  124 . Pressure in the control line  18  builds shearing the shear pins  94  holding the valve piston  108  in place. The pressure forces the valve piston  108  downward so that a piston seat  122  of the valve piston  108  sealably engages and seats on the valve seat located at the bottom of the release mechanism cavity  98 . An optional valve spring  126  helps to hold the valve piston  108  in the seated position in the event of loss of flow. When in the seated position, the valve piston  108  sealably closes the bleed-off line  96  allowing pressure to build in the release mechanism  14 . Specifically, the fluid flows through communication ports  128  in the control line  18  into a pressure cavity  130  defined between the flow responsive valve  92  and the releasing piston  90  in the release mechanism cavity  98 . Once the pressure reaches a sufficient level, the shear pin  68  holding the releasing sleeve  24  to the upper mandrel  22  shears allowing the releasing piston  90  and releasing sleeve  24  to move upward releasing the locking dogs  70  and, ultimately, the packer  10  as previously described. A piston spring  132  biases the releasing piston  90  to an upward, released position. FIG. 6 shows the flow responsive valve  92  closed and the releasing piston  90  and releasing sleeve  24  forced upward to a release position. 
     Preferably, as shown in FIG. 6, the release mechanism  14  also has a pass through line  134  that provides fluid communication through the release mechanism  14  to additional packers  10  or tools located below the packer  10 . The pass through line  134  is preferably axially aligned with the valve bore  110 . To facilitate such communication, the valve piston  108  defines auxiliary passageways  136 . A first set of auxiliary passageways  136  extend from a position above the valve ball  118  when the valve ball  118  is seated on the ball seat  116  to an exterior of the valve piston  108 . Seals  138  between the valve piston  108  and the valve cap  106  positioned below the first set of auxiliary passageways  136  prevent flow through the first set of auxiliary passageways  136  when the flow responsive valve  92  is open (i.e. before the valve piston  108  has moved down on seat). However, after the valve piston  108  moves on seat, the first set of auxiliary passageways  136  communicate fluid from the communication line to a valve annulus  140  formed between the valve piston  108  and the release mechanism cavity  98  wall. A second set of auxiliary passageways  136  defined in the valve piston  108  and providing communication from an exterior of the valve piston  108  to the valve bore  110  are positioned below the seated valve ball  118 . Therefore, fluid may flow around the seated valve ball  118 , back into the valve bore  110 , and into the pass through line  134  without allowing flow into the bleed-off line  96 . 
     FIGS. 7 and 8 show an alternative embodiment for the release mechanism  14  that allows resetting of the release mechanism  14 . In this embodiment, the shear pins  94  are replaced by collets  142  which are nondestructive and may be reset into position. Return springs  144  in the release mechanism  14  bias the release mechanism  14  back to a set position upon removal of pressure. This release mechanism  14  may be combined with a packer  10  having modifications in which the shear pins  50 ,  68  are replaced by nondestructive type setting members, such as collets. In such an arrangement, the packer  10  may be made to be set, released, and reset a plurality of times. 
     While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims which follow. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the word “means” together with an associated function.