Abstract:
A tool and method for drilling a secondary hole (window) from a pre-determined position within a well bore into the adjacent rock or formation. The invention includes an internal (relative to the production tubing) primary deflection wedge transitioning into an externally attached (relative to the production tubing) conical device that aids in the exit from the production tubing through the production casing, where a significant standoff exists between the smaller production tubing (completion) and the larger ID production casing. The primary deflection wedge serves as a directional guide to exit the production tubing. The conical device provides a way to transition and support a milling device to exit the adjacent casing at a desired angle without having the milling device move off the preferred course. This two-part assembly is called a tandem wedge kick off assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to deflection wedges for oil and gas wells and particularly to deflection wedges having a conical body. 
     2. Description of the Prior Art 
     Deflection wedges have been used in drilling oil wells for many years. These wedges serve as a directional guide to exit the production tubing when drilling a secondary hole (window) from a predetermined position within a well bore into the adjacent rock or formation. Traditionally, these wedges have been limited devices that tend to guide the production tubing in a narrow range. Examples of such systems are found in the Following U.S. Pat. Nos. RE40067, RE39141, and 6,206,111, as well as numerous other patents. 
     The current slim hole rotary (SHR) and coil tubing drilling (CTD) industry is restricted to window exits based on current completion designs. For example, many wells in the industry have 7″ casing with 4½″ completion tubing. These wells can be serviced by SHR and CTD with mechanical means of setting a device that is run through the completion tubing and set in the larger ID production casing. 
     New and re-completed wells with smaller completion tubing (&lt;3½″) that maintain larger production casing (non “mono-bore” completions, &lt;7″, 7⅝″ and 9⅝″) present a unique challenge as they are typically not designed for a mechanical means of a casing exit. Currently these type wells incorporate the use of cement “plug back” to mill ramp up to the larger ID casing, after which they time drill an exit. In some cases a pilot hole through the cement is drilled and a whip stock is set in the pilot hole for a mechanical exit in the casing. 
     One problem that these types of operations have is that, when using narrow wedges, the tubing can veer away from the desired line. When this happens, the production tubing often actually runs downward, parallel to the existing well casing, instead of moving off at the desired angle. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention provides a means and method for drilling a secondary hole (window) from a pre-determined position within a well bore into the adjacent rock or formation. The invention includes an internal (relative to the production tubing) primary deflection wedge transitioning into an externally attached (relative to the production tubing) conical device that aids in the exit from the production tubing through the production casing, where a significant standoff exists between the smaller production tubing (completion) and the larger ID production casing. 
     The primary deflection wedge serves as a directional guide to exit the production tubing; the conical device provides a means to transition and support a milling device to exit the adjacent casing. 
     To aid in the transition and support (axial and helical) of the exit, cement is in introduced into the void between the production tubing and the housing of the conical device. This two-part assembly is called a “tandem wedge kick off assembly” (TWKOA). 
     The tandem wedge kick off assembly can be incorporated in any new or re-completed well. It is strategically placed in the completion tubing at a pre-determined depth and allowed to remain during normal production. 
     The TWKOA provides the foundation to mill a casing exit without having to abandon the original well bore, which necessitates, pumping cement for a plug. The TWKOA allows an operator to maintain production from the original well bore, if desired. This is because the internal mechanisms of the TWKOA allow production and intervention until such time the assembly is to be used to create a new well bore (window exit). 
     After the completion of a new lateral well bore, an internal kick off wedge device can be removed from the assembly and access to the original well bore retained. 
     The TWKOA comprises of several different components. First, is the completion tubing used in the TWKOA. This tubing maintains the same OD &amp; ID and physical properties (or greater) as the completion tubing. Next is a locator sub unit, for which are two designs—one accommodates an internal wedge that can be used to start the side track in the production tubing with a 9 degree increment orientation capability spline. The second design has a locating profile that can be used to pinpoint depth and set any style of wedge and anchor by aligning the bottom of the scoop above the secondary wedge/cone, which maintains the direction for the full side track. Next is a bottom sub, which can be a wire line entry guide (WLEG), or more completion tubing. Next is a top sub of the outer housing, which is used to fill the housing with cement. Next is a bottom sub of the housing; this sub has a tight fit over the inner tubing body and a taper (wedge/cone) that acts as a secondary ramp providing a continuous path to the casing for the side track assembly. There is a housing assembly, which is a thin wall pipe that covers the secondary wedge/cone and is filled with cement. The cement here is used to help stabilize the sidetrack assembly as it travels up the secondary ramp and when contacting the outer casing. In addition, there is an orienting snap-in anchor assembly, which holds the internal wedge in place and at the predetermined orientation. It has an external spline that mated to an internal spline (this allows the internal wedge to be oriented in 9 degree increments) and also prevents torque from moving the wedge. In another embodiment, gears can be used that can provide orientation in one-degree increments. Finally, there is an internal wedge, or deflection device, that is placed in the production tubing that diverts the side track assembly in the desired direction for drilling. (This is attached to the snap-in anchor). The internal wedge also can be fitted to a retrievable or permanent anchor and be used with the first design of the locator sub unit with a proper space to still use the outer wedge, if damage to spline assembly does not allow proper set position of the snap in anchor. 
     The used of this device provides a financial benefit because the user does not have to use cement, which is a costly component. The user also saves the rig time involved in the drilling of a pilot hole while still having to insert a mechanical means of making a casing exit. Finally, the user saves the production from the main bore of the well after the side track, which further adds to the economic value of this equipment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view a well bore prior to production tubing and completion being run. 
         FIG. 2  is a detail view the well bore where the production tubing has been run, and showing the cone housing, which is integral to the tubing. 
         FIG. 3  a detail view the well bore showing the primary internal exit wedge has been placed in respective location after engaging the wedge locator. 
         FIG. 4  is a detail view of the well bore showing the entire assembly including the directional path the milling device follows to exit the production tubing, the housing using the cone housing as the secondary deflection and support apparatus, and the adjacent production casing. 
         FIG. 5  is a diagrammatic view of the tandem wedge kick off assembly. 
         FIG. 6  is an exploded view of the top sub, cone housing and secondary exit wedge assembly. 
         FIG. 7  is a detail side view of a length of completion tubing. 
         FIG. 8  is a detail view of the locator sub unit. 
         FIG. 9  is a detail view of the bottom sub with locator profile. 
         FIG. 10  is a detail view of the wire line entry guide. 
         FIG. 11  is an enlarged side view of the secondary exit wedge 
         FIG. 12  is a side detail view of the snap-in anchor assembly with orientation spline. 
         FIG. 13  is a detail view of the primary internal exit wedge-retrieving tool. 
         FIG. 14  is a side detail view of the primary internal exit wedge, or deflection device. 
         FIG. 15  is a side detail view of the primary internal exit wedge-setting tool. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIG. 1 , a casing  100  that is cemented in well bore  101  prior to production tubing and completion being run is shown. The cement  102  surrounds the casing to hold it in place. 
       FIG. 2  shows the well bore and casing after the production tubing  103  has been run. In this view, key elements of the tandem wedge kick off assembly have been installed. These components are placed at the time of the initial well completion. They include a cone housing  40  that contains a conical secondary exit wedge  10  (see  FIG. 11 ), which is integrally attached to the tubing as part of the completion assembly. The cone housing  40  has an open channel  40   a  and the conical secondary exit wedge has an open channel  11  though its center to permit the free flow of oil or gas through it for normal well production. Note that the conical secondary exit wedge  10  is placed at the pre-determined “exit” point relative to the production tubing and production casing. Also installed at this time is a bottom sub  20  with a deflection wedge locator  23  (see  FIG. 9 ); a top sub  30  for the cone housing  40 . 
     Once this unit is installed, the well can be operated for as long as desired. When the operator wants to open a window, additional components are added as discussed below. 
       FIG. 3  shows a primary internal exit wedge  50  that has been placed in its respective location after engaging the primary internal exit wedge locator  23  in the bottom sub  20  (see  FIG. 9 ). The direction angle or “tray face”  53  of the primary internal exit wedge  50  can be set anywhere in 1 degree increments for 360 degrees, as discussed below. 
       FIG. 4  shows the full assembly including the directional path the milling device  105  follows to exit the production tubing  103 , the cone housing  40  using the secondary exit wedge  10  as the secondary deflection and support apparatus, and the adjacent production casing  100 . Also shown is an additional quantity of drilling mud  106  that is used to aid in the drilling. Note that the primary internal exit wedge  50  initially steers the milling device toward the side casing and the secondary exit wedge  10  ensures that the milling device stays on the desired path. 
       FIG. 5  is a diagrammatic view of the tandem wedge kick off assembly, showing the major components as discussed above. The production tubing  103  is shown extending upward of the top sub  30 . It attaches to the regular tubing used in the well completion. The top sub  30  is shown installed. A cement filling port  31  is shown on the side of the top sub (see also  FIG. 6 ). This port is used to fill the outer shell of the cone housing  40  with cement  41 . Note that there is a vent port  42  at the bottom of the cone housing. This allows air to escape the cone housing when the cement is being poured. At the bottom of the cone housing is the secondary exit wedge  10 . Note that, as discussed above, the secondary exit wedge  10  has an open center  11  of the same I.D. as the production tubing (see also  FIG. 11 ). This allows full flow to pass through the TWKOA during normal well operations. Below the secondary exit wedge  10  is the bottom sub  20 . Within the bottom sub  20  is a latch housing  21 . Within the latch housing is a latch assembly  23 . The latch assembly is used to secure the primary internal exit wedge  50  that has been placed in respective location after engaging latch assembly. 
       FIG. 6  is an exploded view of the top sub  30 , cone housing  40  and secondary exit wedge  10 . In this view, the cement fill port  31  in the top sub is shown from the front view. Note that the top sub  30  has threads  33  that engage threads in the cone housing  40 . Note also that the secondary exit wedge  10  is also threaded (see  FIG. 11 ). 
       FIG. 7  is a detail side view of a length of completion tubing  103 . This tubing is made in specific lengths and is assembled as the well is being completed. 
       FIG. 8  is a detail view of the locator sub collet assembly unit  44 . This unit is used to orient the primary internal exit wedge  50  properly and then, in conjunction with the snap-in anchor assembly  70  (see  FIG. 12 ) is used to lock the assembly in place. The locator sub collet assembly unit  44  has a set of ears  45  that snap into matching ears  72  on the snap-in anchor assembly  70 . In the preferred embodiment, both the snap-in anchor assembly  70  and the locator sub collet assembly unit  44  have 360-degree gears installed. In the case of the locator sub collet assembly unit  44 , the gear is  46 . This gear aligns with the matching gear  73  in the snap-in anchor assembly  70 . The locator sub collet assembly unit  44  is then turned until the proper position is reached and the gears are meshed and locked. Note that both of these types of units are readily used in the oil drilling industry and are well known in the art. 
       FIG. 9  is a detail view of the bottom sub  20  with locator profile  23 . The locator profile is used to set the position of the primary internal exit wedge  50 , by marking the lowest position the primary internal exit wedge  50  can be positioned. As shown in  FIG. 3 , for example, the bottom of the primary internal exit wedge  50  shown atop the locator profile  23 , which acts as a stop for the primary internal exit wedge  50 . 
       FIG. 10  is a detail view of the wire line entry guide  60 . This tool is used for well installation work involving a wire line. 
       FIG. 11  is an enlarged side view of the secondary exit wedge  10 . The secondary exit wedge has an open center  11  that conforms to the I.D. of the production pipe in use in the well. The secondary exit wedge has a flat top  12  and sloping sides  13 . The sloped sides end at the threaded portion  14 . Below the threads, the secondary exit wedge extends downward vertically for a small distance before angling back in to the center as shown. 
       FIG. 12  is a side detail view of the snap-in anchor assembly  70  with orientation spline  71 . As discussed above this assembly also has ears  72  and a gear  73  that mesh with the ears and gear on the locator sub collet assembly unit  44 . 
       FIG. 13  is a detail view of the primary internal exit wedge-retrieving tool  80 . This tool is used to remove the primary internal exit wedge  50  after the window has been completed. It does this as follows. At the bottom of the primary internal exit wedge-retrieving tool  80  is a shaft  81  that extends downward through the primary internal exit wedge and into the primary internal exit wedge-setting tool  90 , where it is screwed into the receiver  91 . With the three units connected, the retrieving tool removes the entire assembly when the drilling and milling operations is complete. 
       FIG. 14  is a side detail view of the primary internal exit wedge  50 . As noted above, this device is used to create the initial angle for the milling element to angle off to cut the window. The primary internal exit wedge  50 , as noted above, also has a cylindrical opening  55  through it that allows the shaft  81  of the primary internal exit wedge-retrieving tool  80  to pass through it so that it can connect to the primary internal exit wedge-setting tool  90 . In this way the primary internal exit wedge-retrieving tool, the primary internal exit wedge and the primary internal exit wedge-retrieving tool are connected together so that they are set in place as one unit and later removed as one unit. 
       FIG. 15  is a side detail view of the primary internal exit wedge-setting tool  90 . This tool is used to position the primary internal exit wedge  50  in the production tubing and to adjust its position to the desired angle to form the window, as discussed above. 
     The present disclosure should not be construed in any limited sense other than that limited by the scope of the claims having regard to the teachings herein and the prior art being apparent with the preferred form of the invention disclosed herein and which reveals details of structure of a preferred form necessary for a better understanding of the invention and may be subject to change by skilled persons within the scope of the invention without departing from the concept thereof.