Abstract:
The invention provides a running tool for a wellbore component. In one aspect, the tool includes a body having a longitudinal bore therethrough with an upper end for connection to a tubular run-in string and a selective attachment assembly for a wellbore component therebelow. A flow directing member is disposed in the bore and is movable between a first and second position. At a predetermined flow rate through the member, the member moves to the second position and directs fluid towards the selective attachment assembly, thereby causing the running tool to become disengaged from the wellbore component after the wellbore component has been actuated and fixed in the wellbore.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to running tools and wellbore components for use in a well. More particularly, the invention relates to a running tool for installing a wellbore component in a well. More particularly still, the invention relates to a flow-actuated release mechanism for a running tool. 
     2. Background of the Related Art 
     An oil or gas well includes a wellbore extending from the surface of the well to some depth therebelow. Typically, the wellbore is lined with a string of tubular like casing, to strengthen the sides of the borehole and isolate the interior of the casing from the earthen walls therearound. In the completion and operation of wells, downhole components are routinely inserted into the well and removed therefrom for a variety of purposes. For example, in some instances it is necessary to isolate an upper portion of the wellbore from a lower portion and a bridge plug can be inserted into the wellbore to seal the upper and lower areas from each other. In other instances, it is desirable to seal an annular area formed between two co-axial tubulars or between one tubular and an outer wall of the wellbore and a packer is typically inserted into the wellbore to accomplish this purpose. 
     In each instance, wellbore components are run into the wellbore on a tubular run-in string with a running tool disposed between the lower end of the tubular string and the wellbore component. Once the wellbore component is at a predetermined depth in the well, it is actuated by mechanical or hydraulic means in order to become anchored in place in the wellbore. Hydraulically actuated wellbore components require a source of pressurized fluid from the tubular string thereabove to either actuate slip members fixing the component in the wellbore or to inflate sealing elements to seal an area between the outside of the component and the inner wall of the wellbore therearound. Once actuated, the wellbore components are separated from the running tool, typically through the use of some temporary mechanical connection which is caused to fail by a certain mechanical or hydraulic force applied thereto. After the shearable connection has failed, the running tool and the tubular string can be removed from the wellbore leaving the actuated wellbore component therein. 
     Presently, more and more wellbore components are inserted into wells using a tubular string made up of coiled tubing. Coiled tubing, because it is light, flexible, compact and easily transported is popular for delivering wellbore components. For example, rather than assembling a tubular string with sequential joints of rigid pipe, coiled tubing can be delivered to the well site on a reel and simply unwound into the wellbore to the desired length. Additionally, when a wellbore component must be inserted into a live well, coiled tubing, with its constant outer diameter, is easier to use with pressure retaining components like stripers than sequential tubular sections having enlarged threaded connectors therebetween. 
     In spite of the advantages related to coiled tubing run-in strings for wellbore components, there are also disadvantages. For example, most wellbore components run into a well on coiled tubing are designed to be actuated with pressurized fluid delivered through the coiled tubing. Subsequently, these same components are designed to be disconnected from running tools by shearing a shearable connection between the running tool and the wellbore component. Coiled tubing, because it is relatively thin-walled, can expand in diameter when pressurized fluid is present in its interior. When setting a wellbore component, the pressurized fluid delivered through the coiled tubing adequate to set the component can also be adequate to expand the coiled tubing slightly resulting in a shortening of the coiled tubing string. This shortening can produce an upwards force which causes the shearable connection between the running tool and the component to fail, thereby disconnecting the running tool from the component before the component is completely set in the wellbore. There are other problems related to shearable connections between running tools and wellbore components that are present no matter what type of tubular run-in string is utilized. For example, a shearable connection which has been designed based upon faulty calculations can fail and dislodge the running tool from the wellbore component prematurely. Additionally, some shearable connections are designed whereby the shear pins are partially exposed to fluid pressure used to set the wellbore component. The result can be a shearable connection that fails prematurely. 
     There is a need therefore, for a wellbore component assembly which can be more easily inserted into a wellbore. There is a further need for a running tool for a wellbore component which does not rely upon physical force to become disconnected from the wellbore component. There is yet a further need for a running tool for a wellbore component having a detachment mechanism that is flow-actuated rather than actuated with physical force. There is yet a further need for a wellbore component assembly including a running tool which can be run into a well on a tubular string of coiled tubing. There is yet a further need for a running tool having a release mechanism that will not release prior to the setting of the wellbore component in the wellbore. 
     SUMMARY OF THE INVENTION 
     The invention provides a running tool for a wellbore component. In one aspect, the tool includes a body having a longitudinal bore therethrough with connection means at an upper end for connection to a tubular run-in string and a selective attachment assembly for a wellbore component therebelow. A flow directing member is disposed in the bore and is movable between a first and second position. At a predetermined flow rate through the member, the member moves to the second position and directs fluid towards the selective attachment assembly, thereby causing the running tool to become disengaged from the wellbore component after the wellbore component has been actuated and fixed in the wellbore. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. 
     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. 
     FIG. 1 is a section view of the running tool and wellbore component assembly of the present invention disposed in a cased wellbore. 
     FIG. 2 is a section view of the assembly of FIG. 1 with an inflatable element of the wellbore component actuated against the side of the wellbore. 
     FIG. 3 is a section view of the assembly illustrating the running tool dislodged from the wellbore component. 
     FIG. 4 is a section view of a portion of the wellbore component illustrating the actuation of the component in the wellbore. 
     FIG. 5 is an enlarged section view of the components shown in FIG.  4 . 
     FIG. 6 a section view of the running tool depicting a flow actuated sleeve in a longitudinal bore thereof. 
     FIG. 7 is a section view of the assembly running tool showing the flow-actuated sleeve in a second position and collet fingers dislodging from the wellbore component. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a section view of the running tool and wellbore component assembly  100  of the present invention disposed in a cased wellbore  105 . In the embodiment shown in FIG. 1, the assembly  100  includes a running tool  200  with a bridge plug  300  disposed at the end thereof. The bridge plug includes an inflatable element  305 . While the wellbore component shown in the Figures and discussed herein is a bridge plug, it will be understood that the assembly could include a packer or any other downhole component designed to be transported into a wellbore and anchored therein. At an upper end, the assembly is attached with a threaded connection  107  to a run-in string  110 . In one aspect of the invention, the assembly  100  is run into the well on run-in string of coiled tubing. Typically, other components (not shown) like a double flapper valve, tubing end locator and emergency disconnect would be disposed between the running tool  200  and the coiled tubing string  110 . The running tool  200  includes a longitudinal bore therethrough providing a path for pressurized fluid between the coiled tubing string  110  and the bridge plug  300  as will be described herein. 
     FIG. 2 is a section view of the assembly  100  of FIG. 1 with the inflatable element  305  inflated against the interior of the wellbore  105 . The inflatable element  305  is actuated with pressurized fluid from the coiled tubing string  110  and serves to seal an annular area  310  formed between the inside surface of the wellbore  105  and the exterior of the bridge plug  300 . The inflatable element  305  may have any number of configurations on the outside thereof to effectively seal the annulus  310 . For example, the inflatable element may include grooves, ridges, indentations or protrusions designed to allow the member  305  to conform to variations in the shape of the interior of wellbore casing (not shown). Alternatively, the inflatable member  305  can seal an annular area created by a non-lined borehole. The inflatable member  305  is typically fabricated from a thermoplastic, an elastomer, or a combination thereof. 
     FIG. 3 is a section view of the assembly illustrating the running tool  200  dislodged from the actuated bridge plug  300  therebelow. A collet assembly  205  disposed on the running tool  200  has been disconnected from the bridge plug  300 . In this manner, the bridge plug  300  with its inflatable element  305  is left in the wellbore while the running tool  200  and coiled tubing run-in string are removed. A fish neck  312  formed at the upper end of the bridge plug  300  provides a means for retrieving the bridge plug  300  at a later time. A shearable connection (not shown) fixes the fish neck  312  in the interior of the bridge plug and is caused to fail in order to deflate the inflatable element  305  and remove the bridge plug  300  from the wellbore  105 . 
     FIG. 4 is a section view of a portion of the bridge plug  300  illustrating the actuation means to inflate the inflatable member  305 . Disposed in the bridge plug and co-axially disposed around a central bore of the plug is a valve  320  that selectively permits fluid communication between central bore  301  of the bridge plug  300  and inflatable member  305 . Initially, valve  320  is held in a closed position by a shearable connection  322  as well as a spring member  325  and is designed to open with a predetermined pressure that is sufficient to overcome the shearable connection  322  and the spring member  325 . The predetermined pressure is applied to a column of fluid in the coiled tubing run-in string  110  that extends through the running tool  200  and the bridge plug  300 . In FIG. 4, the valve  320  is shown in the open position with the shearable connection  322  having failed and the inflatable member  305  in fluid communication with fluid in the central bore  301  of the bridge plug  300 . The central bore  301  is initially blocked at a lower end by a plug  315  which is held in a first position within the interior of the bridge plug by a separate shearable connection  317 . In FIG. 4, the plug  315  is shown in a second position after the shearable connection  317  has failed and the plug  315  has moved downward to permit fluid to flow out the lower end of the bridge plug  300 . 
     FIG. 5 is an enlarged section view showing the valve  320  and including arrows  321  illustrating path of fluid from the central bore  301  of the bridge plug to the inflatable member therebelow. Initially, pressurized fluid acts upon an upper surface  323  of the annularly shaped valve  320  until the shearable connection  322  holding the valve  320  in a first position fails. Thereafter, the fluid pressure moves the valve against spring member  325  as illustrated in FIG.  5 . As depicted by the arrows  321 , the fluid passes from the central bore  301  of the bridge plug through apertures  303  and follows a path around the outside of the valve  320  and the spring member  325  to reach the inflatable element  305  therebelow. 
     The sequence of events required to anchor the bridge plug  300  are as follows: The assembly  100  is run into the well to a predetermined depth where the bridge plug  300  will be anchored in the wellbore  105 . A first pressure is thereafter applied to the fluid column in the assembly  100  until the shearable connection  322  fixing the valve  320  in the plug fails, permitting the valve to move to an open position and exposing the inflatable member  305  to pressurized fluid. As the inflated pressure of the inflatable member  305  is reached, the shearable connection  317  retaining the plug  315  at the lower end of the bridge plug  300  in the first position fails and the plug falls to a second position, thereby permitting fluid to pass through the bridge plug  300  and into the wellbore  105  therebelow. Typically, the pressure required to inflate the inflatable member  305  to the desired pressure and the pressure required to break the shearable connection  317  holding the plug  315  in its first position will be substantially the same, and both will be higher than the pressure necessary to cause shearable connection  322  to fail. This ensures that the inflatable member becomes fully inflated before the plug at the bottom of the bridge plug becomes dislodged. As the plug  315  is dislocated and fluid passes into the wellbore  105 , the spring loaded valve  320  returns to its first position, thereby closing the fluid path to the inflatable member and preventing fluid from escaping from the inflatable member  305 . At this point, the bridge plug  300  is anchored and set in the wellbore  105 . 
     FIG. 6 is a section view of the running tool  200 . Connection means  102  provides a means for connection to the coiled tubing running string  110  at an upper end of the tool  200 . An orifice  255  in the circle of the tool provides fluid communication between the outside of the tool and the bore  215  for pressure equalization during run-in. Disposed in the bore  215  of the tool  200  is a flow-actuated sleeve  210  shown in a first position. The sleeve  210  is held in the first position by a shearable connection  220  which axially fixes the sleeve  210  in the bore  215 . 
     The flow-actuated sleeve  210  is constructed and arranged to permit the flow of fluid through its central bore while in the first position, but to divert the flow of fluid after shifting to a second position. As illustrated in FIG. 6, a port  231  formed in a wall of the running tool  200  is initially blocked to the flow of fluid by the sleeve  210  which is equipped with seals  211 ,  212 . Additionally, apertures  225  formed in a well of the sleeve are initially misaligned with mating ports  227  formed in the well of the running tool  200 . 
     The flow-actuated sleeve  210  remains in the first position until fluid flow across a piston surface  224  formed at the upper end of the sleeve is adequate to overcome the shearable connection  220  retaining the sleeve in the first position. The design of the bridge plug  300  prevents an adequate amount of fluid flow prior to the inflation of the inflatable member  305 . 
     FIG. 7 is a section view of the running tool  200  showing the flow actuated sleeve  210  in the second position within the bore  215  of the tool  200 . In order for the sleeve to assume this position, the bridge plug  300  must be anchored with the inflatable member  305  inflated and the plug  315  at the lower end of the bridge plug  300  dislodged, thereby permitting fluid to be circulated through the apparatus  100 . 
     With the sleeve  210  in the second position, fluid communication is permitted between the bore  215  of the tool and the collet assembly  205  as will be further described below. Also in FIG. 7, apertures  225  formed in the wall of the sleeve  210  are aligned with mating ports  227  formed in the wall of the running tool  200 . The apertures  225  and ports  227 , when aligned, create a path for fluid to the outside of the tool  200  in case there should be some obstruction below the bridge plug  300  in the wellbore. This alternative fluid path permits circulation of fluid, and disengagement of the running tool  200  from the bridge plug  300 , even if the wellbore below the bridge plug is blocked. 
     In addition to operating the flow actuated sleeve  210  in the forgoing manner, the sleeve can also be moved from the first to the second position by simple application of pressure if it becomes necessary to quickly and safely disconnect the running tool  200  from the bridge plug  300  without the use of flow actuated means. For example, by dropping a ball or other substantially spherical-shaped object into the wellbore to fall within the coiled tubing string  110 , the object can be made to land on the surface of the sleeve  210 , blocking fluid flow therethrough. Thereafter, pressure applied to a column of fluid in the coiled tubing string  110  will be transmitted directly to the sleeve  210 , overcoming the shearable connection  220  holding the sleeve  210  in the first position. After the sleeve and ball move to the second position, fluid communication is established between the bore  215  of the tool  200  and the collet assembly  205  therearound. 
     Visible in FIG. 7 is collet assembly  205  disposed about the body  230  of the running tool  200 . The collet assembly  205  is slidingly disposed about the body and preferably biased towards the coiled tubing string thereabove by a spring  235  also disposed about the body of the tool  200 . The spring  235  acts at a first end against a shoulder  206  formed on body  205  and at a second end against an upper end  246  of the collet assembly  205 . The collet assembly  205  includes a plurality of equally spaced fingers  240  attached at a lower end thereof and flexible about the bridge plug  300 . Each of the fingers  240  include an inwardly directed formation  245  which is constructed and arranged to be retained in a groove  350  formed around the body  355  of the bridge plug  300 . Additionally, a retaining member  400  disposed about the body  355  of the bridge plug  300  retains the fingers  240  in a closed position within groove  350 . 
     The collet assembly  205  is disposed about the body  230  of the running tool whereby the assembly  205  moves axially with respect to the body  230 . The collet assembly  205  is designed with a chamber  250  formed between an interior surface  207  of the collet assembly  205  and an outer surface  209  of the body  230  of the running tool  200 . The chamber  250  is in fluid communication with port  231  when the flow actuated sleeve  210  is in the second position. Fluid passing into the chamber  250  causes the collet assembly  205  to move axially in relation to the running tool  200 , against spring member  235 . In FIG. 7, the collet assembly is depicted having moved against the spring member  235  and the fingers  240  of the collet assembly  205  are partially released from the groove  350  and the retaining member  400 . With the fingers  240  disengaged from the bridge plug  300 , the run-in string  110  and running tool  200 , may be removed from the wellbore  105  leaving the anchored bridge plug  300  in place. An additional spring-loaded flow control valve which is normally in the opened position is disposed about the fish neck  312  and is utilized to seal the bore through the body and complete the setting of the bridge plug in a wellbore as the running tool is removed therefrom. 
     As the forgoing demonstrates, the invention includes an effective way to release a wellbore component from a running tool. The release mechanism, because it is flow actuated is less susceptible to premature release than conventional designs and the release does not take place until the wellbore component is set in the wellbore. 
     While 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 that follow.