Patent Publication Number: US-6910538-B2

Title: Whipstock collet latch

Description:
This application claims the benefit of Provisional Application No. 60/381,352, filed May 20, 2002. 

   BACKGROUND OF THE INVENTION 
   A. Field of the Invention 
   The present invention relates to a collet latch for attaching a drill to a whipstock during run in to reduce the number of trips necessary to slant drill a well bore. 
   B. Description of the Prior Art 
   The use of a whipstock to slant drill through the side of a well bore at an angle is well known. See for instance U.S. Pat. No. 6,315,044 to Tinker issued Nov. 13, 2001, which is incorporated herein by reference, showing a method of locating and orienting a whipstock. Part of the wall of the casing in which the whipstock is located has been pre-milled to facilitate lateral drilling outside of the main well bore. The whipstock is oriented to direct the drill through the pre-milled “window” in the casing to the area surrounding the well bore where it is desired to drill. As the drill is lowered into the well bore, the angled (“concave”) face of the whipstock redirects the drill bit away from the vertical position into contact with the casing surrounding the drill allowing lateral drilling to take place. 
   Previously, as shown in U.S. Pat. No. 6,315,044, the whipstock was run into place during a first run and after removing the entire drill string above the whipstock, the drill was run (“tripped”) into the hole to initiate drilling. This inefficiency of using two trips to install the whipstock and to then insert the drill leads to increased expenses and tooling. It is desirable to run both the drill and the whipstock into the well bore in one trip to save time, equipment and the costs associated therewith. 
   The present invention teaches a new apparatus and method for installing the whipstock and drill simultaneously by a unique arrangement for attaching the whipstock to the drill for concurrent installation. 
   None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. 
   SUMMARY OF THE INVENTION 
   The present invention is accomplished by providing an anchor on the drill body which is extendible to engage an eyelet formed or provided on the whipstock. The anchor is retractable into the body of the drill so that the drill can pass by the whipstock during lateral drilling and out the casing wall without interference. The anchor preferably is extended and retracted by hydraulic force controlled remotely by the operator. The anchor is preferably shaped to match and conform to the outer wall of the drill so that in the closed position, the anchor is contiguous with and does not extend beyond the outer diameter of the drill body. Part of the drill body is preferably removed to allow the anchor to nest within the space provided by the removal of the drill body. 
   Accordingly, it is a principal object of the invention to provide an arrangement for securing the whipstock to the drill for inserting the whipstock. 
   It is another object of the invention to provide a hydraulic activation tool for selectively extending and retracting an anchor on the body of the drill which cooperates with an eyelet on the whipstock to selective join the whipstock to the drill body. 
   Still another object of the invention is to provide a hydraulically retractable anchor on a drill body which withdraws the anchor to prevent any interference between the anchor and the casing or whipstock. 
   It is a further object of the invention to a mechanically set whipstock which is selectively attachable to a drill for running into a well bore. 
   It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
   These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an environmental perspective view of the invention shown mounted in a well casing. 
       FIG. 2A  is a top plan view of the anchor of the present invention shown in an extended position. 
       FIG. 2B  is a top plan view of the anchor locked into the eyelet of the whipstock for run in according to the present invention. 
       FIG. 3  is a top plan view of the anchor in the retracted position. 
       FIG. 4  is partial top plan view of whipstock having an eyelet for receiving an anchor according to the present invention. 
       FIG. 5  is a front elevational view of an eyelet according to the present invention for mounting onto a whipstock. 
   

   Similar reference characters denote corresponding features consistently throughout the attached drawings. The present invention 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
   The present invention relates to a new method and arrangement for a single trip run in of the whipstock and drill using a hydraulically activated latch on the drill body. 
     FIG. 1  shows a well bore casing  10  installed in a well (not shown). The drill  12  is shown attached to a whipstock  14 . Though not necessary for the current invention, the whipstock is shown in a typical configuration with a packer body  16  and orientation sub  18  for locating and orienting the whipstock in the proper position as is known in the art and shown in U.S. Pat. No. 6,315,044, which is hereby incorporated by reference. 
   In operation, the whipstock is lowered in the wellbore to the desired location pointing the slanted surface of the whipstock such that it will direct the drill to a point in the casing where lateral drilling is to be performed. In prior devices, the whipstock is run in separately from the drill and is oriented into position. The drill is then run in during a second trip and as the drill contacts the whipstock face, the drill is redirected outwardly into or through the casing into the surrounding earth where lateral drill occurs outwardly from the bore. 
   The present invention teaches a method of running the drill and the whipstock in in one trip, thus saving time, manpower, equipment and thus money. By releasably connecting the whipstock to the drill, the drill can be used to run the whipstock into the bore whereupon the whipstock can be separated from the drill and operated in the normal fashion. 
     FIG. 1  shows the whipstock connected to the drill during run in. As seen in  FIG. 4 , the whipstock has a curved face  42 . The face slants from a top point to a wide base as shown in FIG.  1 . This allows the round drill to ride within the whipstock face to redirect the cutting or abrading element (“face”) of the drill from the vertical run in position to an outwardly facing position to cut through or outwardly away from the bore wall in a lateral direction once the drill is separated from the whipstock. 
   As shown in  FIGS. 2B ,  4  and  5 , in order to connect the drill and the whipstock during run in, a sleeve  44  is provided near the middle of the whipstock face, although the location on the face where the sleeve is connected can easily be closer or farther from the base. However, in the preferred embodiment, the sleeve is near the midpoint to connect to a hydraulic latch finger  30  located at on the body  22  of the drill (“window mill”)  12  intermediate the two drill cutting faces. In the extended position as shown in  FIGS. 2A and 2B , the finger  30  of the clamp can be inserted through the sleeve  44  to lock the drill and the whipstock together. 
   The hydraulic latch  32  has a reservoir  34  connected to or controllable by an actuator (not shown) which by means well known in the art, increases or decreases the pressure in the reservoir  34 . This actuator may be by a pump, a piston, or other device. One skilled in the art would also recognize that the actuator could be a simple mechanical device such as a spring, but is less preferable because of there is less control over when the operation of a spring as compared to a hydraulic actuator. The actuator may be contained within the drill  12 , along the string  24  connecting the drill to the surface, or may be at the surface. The actuator is selectively controlled by an operator (not shown) who activates the actuator to increase or decrease the pressure level in the reservoir  34 . According to the preferred embodiment of the invention, when the pressure of the fluid in the reservoir is increased, the fluid acts against the shoulder  36  to move the shoulder away from the center of the drill body, thus closing the hydraulic latch  32 . When the latch is fully closed, the outer periphery of the finger is preferably contiguous with the outer wall of the drill body to provide a smooth cylindrical drill body when in the closed position as shown in FIG.  3 . This will allow the drill body to smoothly ride within the whipstock face as the drill is deployed as will further herein be explained. 
   When the pressure in the reservoir is released, the finger is allowed to open. However, in the preferred embodiment, it is not necessary that the latch  32  “opens” when the pressure is released, as the latch need only be closed during operation. The latch can be manually “opened” while at the surface when the whipstock is connected to the drill body. However, the latch may be assisted in opening by a spring or strictly by a negative pressure on the shoulder  36  caused by the withdrawal of hydraulic pressure from reservoir  34 . 
   In operation, the pressure of the reservoir  34  is reduced to allow the latch  32  to open. With the finger  32  of the hydraulic latch  36  in the extended position, the finger is manually threaded through and engaged with the sleeve of the whipstock to secure the whipstock to the drill body for run in. It may be necessary to slightly close the latch  32  by raising the pressure of the reservoir  34  to ensure that the sleeve  44  of the whipstock is clamped within the latch  32 . 
   With the whipstock and the drill body thus engaged and connected, the drill and the whipstock are lowered from the surface into the casing  10  of the wellbore. When the whipstock is positioned in the desired location by use of an orientation sub  18  or other device, the drill body may be disengaged from the whipstock. 
   To disengage the drill body from the whipstock, the pressure in the reservoir may be released to ensure that the finger  30  of the latch can move freely, but in most circumstances this precaution is unnecessary. The drill body is then rotated relative to the drill body to rotate and unthread the finger from the sleeve  44 . When the drill body has been rotated sufficiently to disengage the finger  30  of the hydraulic latch  32  from the whipstock sleeve  44 , pressure is added to the reservoir  34  to close the latch  32 . 
   With the body  22  of the drill  12  restored to it smooth cylindrical exterior, the drill can be lowered relative to the whipstock  14 . As the drill (or mill) is lowered the drill rides in the curved channel formed by whipstock face, moving the bottom of the drill from a downward facing position to an outwardly facing position. The bottom cutting edge  26  will then engage and cut the casing, or if the casing has already been removed as a window, the mill will contact the earth surrounding the casing cutting a lateral path through the earth. The larger cutting face  28  will follow the bottom lower face  26  boring a wider hole through the earth. 
   One skilled in the art would recognize that the process could be reversed to reengage the whipstock sleeve to withdraw the whipstock from the well, but this would normally be impractical to realign the sleeve  44  and the latch finger  30 . However, it may be necessary immediately after removing the finger from the sleeve to reinsert the finger into the sleeve should some unforeseen event occur. In this case, the procedure described above would be reversed to reinsert the finger  30  into the sleeve  44 . 
   One skilled in the art would also appreciate that instead of unthreading the latch finger  30  from the sleeve  44 , that the sleeve could be provided with perforations  46  ( FIG. 5 ) or otherwise frangible such that just by closing the latch  32 , the finger  30  would tear through the wall of the sleeve  44  to release the drill body from the whipstock  14  without departing from the scope of the invention. However, this would require replacement of the sleeve during each run in and is thus less preferable. 
   It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.