Abstract:
A retrieval tool and method for retrieving a remote tool with a threaded connection from a remote location. The retrieval tool includes a rotational drive member which rotates an attachment sub having a complimentary threaded portion. An articulated shaft assembly permits the attachment sub to move laterally and angularly with respect to the axis of the rotational drive member. A fluid conduit supplies fluid pressure for releasing the remote tool.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to devices and methods for engaging and removing remote tools having threaded portions from a remote location. In particular aspects, the invention relates to devices and methods for removing certain threaded tools from a subterranean wellbore. 
     2. Description of the Related Art 
     A number of well tools are employed that are left in the wellbore disconnected from a running or retrieval string. In some cases, these tools are difficult to secure and remove since they present a neck portion that is offset or at an angle with respect to the axis of the wellbore. This generally includes any tool that is left in the wellbore at an angle to the main wellbore axis and is not connected to a running or retrieval string (e.g., directional drilling or driving tools). In addition, some tools require the application of fluid pressure to release them from the wellbore. 
     SUMMARY OF THE INVENTION 
     The invention provides devices and methods for removal of a tool from a remote location such as a subterranean wellbore. A retrieval tool is described that generally includes an outer housing, an rotational drive element and an articulated shaft assembly that carries an attachment sub. The attachment sub has a threaded portion that is complimentary to the threaded neck portion of the remote tool to be retrieved. In a described embodiment, the outer housing and rotational drive element are used to locate and guide the attachment sub onto the neck portion of the remote tool so that it can be threadedly attached to the neck portion. 
     The outer housing includes a locating plate with an opening that is shaped and sized to receive the neck portion of the remote tool. The opening is offset from the central axis of the wellbore and functions to capture the neck portion of the remote tool. In addition, the opening in the locating plate functions to position the attachment sub so that it can be further guided toward the neck portion. 
     In a described embodiment, a guide sleeve with an enlarged opening radially surrounds the threaded portion of the attachment sub to assist in capture of the neck portion. In the described embodiment, the guide sleeve includes a tapered edge guide portion that assists in guiding the attachment sub toward the neck portion of the remote tool. 
     Also in described embodiments, a positioning assembly is retained within the inner body and functions to govern angular and lateral orientation of the attachment sub so that it can be readily affixed by threading to the neck portion. In a described embodiment, the positioning assembly includes a number of plates and rings that are in a stacked configuration and retain the attachment sub in a captive arrangement. The plates and rings are able to move laterally with respect to one another, thereby governing orientation of the attachment sub. In described embodiments, the positioning assembly also includes an articulated shaft assembly made up of a set of yokes and shafts to alter orientation of the attachment sub. 
     In featured embodiments, a clutch assembly operably interconnects the rotational drive member with the outer housing. The clutch assembly functions to release the outer housing from fixed attachment with the rotational drive member and articulated shaft assembly so that the rotational drive assembly will apply torque to the attachment sub following seating of the attachments sub onto the threaded portion of the remote tool. The clutch assembly allows the attachment sub to be threaded onto the neck portion of the remote tool after the neck portion has been captured by the retrieval device. The clutch assembly includes frangible shear members that are broken in order to free the outer body from the inner body and articulated shaft portion. Also in a described embodiment, the clutch assembly includes a key and slot arrangement that allows the outer housing to be carried by the rotational drive member after the shear members are broken. 
     In described embodiments, the retrieval device includes a fluid conduit that extends through the interior of the rotational drive member, articulated shaft assembly and attachment sub. Preferably, the fluid conduit is operably interconnected with a fluid pump at surface so that fluid pressure may be supplied through the conduit to the remote tool to be retrieved. This features assists in tool removal in instances where application of fluid pressure is used to release the tool within a wellbore from either the wellbore or interconnected tools within the wellbore. 
     In an exemplary described method of operation, a retrieval device constructed in accordance with the invention is secured to a rotatable running string and disposed within a remote location such as a wellbore which contains the remote tool to be removed. The retrieval device is placed proximate the remote tool. Rotation of the running string will rotate the retrieval device, including the outer housing. As the retrieval device is rotated by the running string, the neck portion of the remote tool becomes aligned with the opening in the locating plate of the retrieval device. The neck portion passes through the locating plate opening and positions the attachment sub in the correct orientation relative to the neck portion. The guide sleeve guides the attachment sub into the thread of the neck portion. The positioning assembly permits the attachment sub to be angled and moved laterally as necessary to be threaded into engagement with the remote tool via rotation of the running string. 
     Once the attachment sub has been threadedly engaged with the remote tool, the running string, retrieval tool and remote tool are withdrawn from the remote location. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages and further aspects of the invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawing and wherein: 
         FIG. 1  is a side, cross-sectional view of a wellbore containing a remote tool to be removed and a retrieval tool constructed in accordance with the present invention. 
         FIGS. 2A and 2B  are an enlarged side, cross-sectional view of the retrieval tool and remote tool of  FIG. 1  during running in of the retrieval tool. 
         FIGS. 3A and 3B  are an enlarged side, cross-sectional view of the retrieval tool and remote tool of  FIG. 1  during tool orientation. 
         FIGS. 4A and 4B  are an enlarged side, cross-sectional view of the retrieval tool and remote tool of  FIG. 1 , now with the locating plate having been landed. 
         FIGS. 5A and 5B  are an enlarged side, cross-sectional view of the retrieval tool and remote tool of  FIG. 1 , now with the attachment sub fully engaged with the remote tool. 
         FIG. 6  is an exploded view of portions of an exemplary positioning assembly used within the retrieval tool shown in  FIGS. 2A-2B . 
         FIG. 7  is an isometric detail depicting the locating plate of the retrieval tool in contact with the neck portion of the remote tool. 
         FIG. 8  is an isometric detail depicting the locating plate of the retrieval tool in contact with the neck portion of the remote tool and the opening of the locating plate aligned with the neck portion. 
         FIG. 9  is an exploded, isometric view of portions of an exemplary articulated shaft assembly used within the retrieval tool. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates an exemplary wellbore  10  that has been drilled through the earth  12  and has been lined with metallic casing  14 . The wellbore  10  has a central axis, which is illustrated by the dashed line  16 . A remote tool  18  to be removed is located within the wellbore  10 . In the described embodiment, the remote tool  18  is releasably secured either to the wellbore  10  itself or to another tool (not shown) within the wellbore  10  and requires the application of a particular amount of fluid pressure to the upper portion of the remote tool  18  in order to release the remote tool  18  and allow it to be removed from the wellbore  10 . The remote tool  18  has a shoulder  20  with a neck portion  22  that extends axially upwardly from the shoulder  20 . As can be seen in FIG.  2 B, the neck portion  22  has an interior threaded portion  24 , by which the remote tool  18  is secured for removal from the wellbore  10 . It is noted that, in this example, the remote tool  18  has a central axis  26  that is angularly offset from the axis  16  of the wellbore  10 . In addition, in this example, the neck portion  22  is radially or laterally offset from the central axis  16  of the wellbore  10 . 
     A retrieval tool  28 , which is constructed in accordance with the present invention, is shown disposed within the wellbore  10  by a rotary running string  30 . The running string  30  may be formed of a number of production tubing string sections that are secured together in an end-to-end fashion. Alternatively, the running string  30  may be coiled tubing. 
     An exemplary retrieval tool  28  in depicted in greater detail in  FIGS. 2A-2B  and includes a generally bell-shaped outer housing  32 . In the depicted example, the outer housing  32  includes an upper, reduced diameter portion  34  and a lower, enlarged diameter portion  36 . Openings  38  are disposed through the angled shoulder  40  that interconnects the upper portion  34  with the lower portion  36 . The openings  38  allow fluid bypass when running in and help to reduce the overall weight of the retrieval tool  28 . The lower end of the lower portion  36  presents an opening  42  that is closed off by a locating plate  44 . The locating plate  44  includes an elongated opening  46  that is shaped and sized to receive the neck portion  22  of the remote tool  18 . Additionally, in certain embodiments, there is a lateral opening  47  that is formed within the lower portion  36 . The lateral opening  47  provides clearance for interior shaft elements at high angles of deviation and allows access to inner components during assembly, maintenance and operation. 
     The outer housing  32  is releasably secured by frangible shear members  48  to an articulated shaft assembly, generally shown at  50 . Preferably, the shear members  48  are disposed through the upper, reduced diameter portion  34  of the outer housing  32 . When the shear members  48  are intact, the rotational drive element (described shortly) will transmit torque to the outer housing  32 . The articulated shaft assembly  50  functions to allow lateral and angular movement of an attachment sub  52  within the outer housing  32 . The attachment sub  52  includes a threaded portion  54  that is complimentary to the threaded portion  24  of the remote tool  18 . 
     The exemplary articulated shaft assembly  50  includes an inner body top sub  56  which is affixed at its lower end to an inner body  58 . A rotational drive element  60  is disposed radially within the inner body top sub  56 . The rotational drive element  60  is rotated by the running string  30  and will transmit torque to other components of the retrieval tool  28  as described herein. It is noted that the shear members  48  interconnect the outer housing  32  to the inner body top sub  56 . Elongated slots  62  are formed within the inner body top sub  56 . A retainer key  64  is disposed within each slot  62 . The retainer keys  64  are secured in place against the rotational drive element  60  by securing plates  66 . When the shear members  48  are used to interconnect the outer housing  32  to the rotational drive element  60 , the retainer keys  64  are located proximate the lower ends of the elongated slots  62 . It should be understood that the retrieval tool  28  features a clutch assembly that includes the shear members  48 , retainer keys  64  and slots  62 . The clutch assembly of the retrieval tool  28  allows the rotational drive element  60  to be selectively released from fixed engagement with the outer housing  32  so that the rotational drive element  60  will thereafter primarily apply torque to the attachment sub  52  to drive it into threaded engagement with the neck portion  22  of the remote tool  18 . The outer housing  32  will still rotate with the inner body  58  and flex joint top sub  60  due to the presence of the retainer keys  64  within slots  62 . However, torque is now applied from the rotational drive element  60  to the attachment sub  52  via the telescopic shaft assembly  72  (described shortly) after the shear members  48  are broken. 
     The lower end of the rotational drive element  60  is affixed by pins  68  to an upper flex joint yoke  70 . The yoke  70  is affixed to a telescopic shaft assembly  72  also using pins  68 .  FIG. 9  is an exploded view that helps illustrate an exemplary connection of the yoke  70  with neighboring components. The shaft assembly  72  is made up of an upper keyed shaft  74  and a lower keyed shaft  76 . The upper keyed shaft  74  receives the lower keyed shaft  76  in a nested configuration, and the two are capable of telescopic movement with respect to each other between extended and retracted positions. The lower shaft  76  is affixed to a lower flex joint yoke  78 , and the lower flex joint yoke  78  is, in turn, interconnected by pins  80  to the attachment sub  52 . Interconnection of the lower flex joint yoke  78  with neighboring components is done in a manner similar to that of the upper yoke  70 . A cylindrical guide sleeve  82  radially surrounds the attachment sub  52  and is attached to it. Preferably, the guide sleeve  82  presents an enlarged lower opening  84  with a tapered edge  86  to serve as a guide portion. It is noted that the lower opening  84  should be substantially aligned with the opening  46  of the locating plate  44  (see  FIG. 3B ). 
     The outer housing  32  defines an interior chamber  88 , and the inner body  58  resides within the chamber  88 . Openings  90  are disposed through the inner body  58 . The openings  90  allow fluid bypass when running in and also help to reduce the weight of the retrieval tool  28 . 
     In the described embodiment, the inner body  58  also contains a positioning assembly, which is generally indicated at  92 . The positioning assembly  92  is used to angularly and laterally orient the attachment sub  52  to permit it to be aligned with and threadedly affixed to the remote tool  18 . Some portions of the positioning assembly  92  are best understood with further reference to  FIG. 6  which shows certain components of the positioning assembly  92  in an exploded view. Generally, the positioning assembly  92  includes a plurality of components that captively retain the attachment sub  52  and which are slidably moveable with respect to one another within the inner body  58  to govern the angular and lateral orientation of the attachment sub  52 . The attachment sub  52  is retained captively within a number of openings that are disposed through these components. The exemplary positioning assembly  92  includes a set down plate  94  that is secured within the inner body  58 . An opening  96  is disposed through the set down plate  94 , and the attachment sub  52  extends through the opening  96 . The opening  96  is elongated and large enough to permit the attachment sub  52  to be moved around within the opening  96 . As can be seen in  FIG. 6 , two flanges  98  extend downwardly from the lower side of the set down plate  94  defining a channel  100  between them. 
     The exemplary positioning assembly  92  also includes a set down ring  102 . The set down ring  102  has an opening  104 , and the attachment sub  52  extends through the opening  104 . The set down ring  102  is shaped and sized to fit within the channel  100  of the set down plate  94  and slide from edge to edge of the set down plate  94  within the channel  100 . 
     The exemplary positioning assembly  92  also includes a load ring  106  that radially surrounds the attachment sub  52  and is located below the set down ring  102 . In addition, a lower set down ring  108 . The lower set down ring  108  has a central opening  110  through which the attachment sub  52  extends. In addition, the lower set down ring  108  has ridges  112  that project upwardly from the upper surface of the lower set down ring  108  and contact the flat edges of the set down ring  102 . 
     Finally, the exemplary positioning assembly  92  includes a lifting ring  114  that is secured within the inner body  58  by a securing nut  116 . The attachment sub  52  extends through an opening  118  in the lifting ring  114 . 
     Fluid is able to pass downwardly through the running string  30  and the retrieval tool  28 . The running string  30  defines a flowbore  120  along its length. The flowbore  120  interconnects with flow opening  122  within rotational drive element  60  and is directed into a flexible fluid conduit  124 . The flexible conduit  124  passes through the upper flex joint yoke  70 , the shaft assembly  72  and the lower flex joint yoke  78 . The conduit then extends to a flow passage  126  that passes through the attachment sub  52 . Thus, fluid may be pumped downwardly from the surface into the flowbore  120  of the running string  30  and it will exit the attachment sub  52 . As a result, fluid pressure may be applied to the remote tool  18  as may be needed to, for example, release the tool  18  from locking interengagement with other tools within the wellbore  10 . Once engaged, fluid pressure can be applied when the remote tool  18  relies on a hydraulic system to release it from the wellbore  10  or from other tools within the wellbore  10 . 
     In an exemplary method of operation, the retrieval tool  28  is affixed to the running string  30  and disposed into the wellbore  10 , as depicted in  FIG. 1 . The retrieval tool  28  is brought into contact with the remote tool  18 . The locating plate  44  of the retrieval tool  28  will contact the neck portion  22  of the remote tool  18 . Typically, the neck portion  22  will not be initially aligned with the opening  46  of the locating plate  44 , as illustrated by  FIG. 7 . Because the shear members  48  are intact, rotation of the running string  30  will transmit torque at this point from the rotational drive element  60  to the outer housing  32 , thereby causing the outer housing  32  to rotate with the running string  30 . The running string  30  and affixed retrieval tool  28  are rotated until the opening  46  is aligned with the neck portion  22  (see  FIG. 8 ). Once so aligned, the neck portion  22  will enter the opening  46 , as shown in  FIG. 3B , preventing further rotation of the outer housing  32  and providing an indication of correct orientation exhibited by an increase in torque. Continuing to lower the running string  30  into the wellbore  10  will bring the neck portion  22  into contact with the tapered edge  86  of the guide sleeve  82 . 
     As the running string  30  and retrieval tool  28  are further lowered, the guide sleeve  82  and the attachment sub  52  move radially outwardly along the tapered edge  86 , as depicted by  FIG. 4B , the guide sleeve  82  functioning to guide the attachment sub  52  into alignment with the neck portion  22  of the remote tool  18 . Once so aligned, further lowering of the running string  30  will bring the locating plate  44  into contact with the shoulder  20  of the remote tool  18  stopping further downward movement of the outer housing  32  and breaking the frangible shear members  48  of the clutch assembly. Once the clutch assembly is disengaged, the rotational drive element  60  is free to move and rotate within the outer housing  32  and further lowering and rotation of the running string  30  will thread the threaded portion  54  of the attachment sub  52  into the threaded portion  24  of the neck portion  22  of the remote tool  18 . Because the frangible shear members  48  have been broken, torque is now transmitted from the rotational drive element  60  to the attachment sub  52  via the articulated shaft assembly  50  rather than to the outer housing  32 . 
     To aid in the threading operation, angular and lateral orientation of the attachment sub  52  is altered by the articulated shaft assembly  50  as well as governed by the positioning assembly  92 . As the attachment sub  52  is urged into an off-center position by the guiding of guide sleeve  82 , the shaft assembly  72  will pivot upon the upper and lower flex joint yokes  70 ,  78  as needed to allow the attachment sub  52  to achieve that position. Also, the shaft members  74 ,  76  of the shaft assembly  72  will move telescopically with respect to each other by extending or retracting as needed to accommodate angular or lateral movement of the upper (non-threaded) end of the attachment sub  52 . In addition, the plates  94 ,  102  and rings  106 ,  108  and  114  of the positioning assembly  92  help orient the attachment sub laterally and angularly to assist with attachment to the remote tool  18 . The attachment sub  52  is held captively within the openings  96 ,  104 ,  110  and  118  within the plates  94 ,  102  and rings  106 ,  108  and  114 . Therefore, as these stacked members slide relative to each other, they govern lateral movement of the attachment sub (relative to the central axis  16 ) and, therefore, help it be threaded together with the angled neck portion  22  of the remote tool  18 . This lateral and angular orientation can be seen by comparison of  FIG. 3B , which depicts an orientation of the attachment sub  52  that is generally aligned with the central axis  16 , with  FIG. 5B , which shows an orientation that departs laterally from the central axis  16 . 
     Once the remote tool  18  has been affixed to the retrieval tool  28 , fluid pressure may be applied through the running string  30  as required to release the remote tool  18 . The running string  30 , retrieval tool  28  and remote tool  18  can then be removed from the wellbore  10  by pulling upwardly on the running string  30 . 
     The foregoing description is directed to particular embodiments of the present invention for the purpose of illustration and explanation. It will be apparent, however, to those skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope and the spirit of the invention.