Abstract:
An embodiment of a cutting tool positionable in a tubular for creating a cut in a tubular includes a body securable within the tubular and a cutting head having a nozzle for discharging a pressurized cutting fluid, wherein the cutting head is rotationally and axially moveable relative to the body. The cutting tool may further include one or more of a positioning mechanism, a linear actuator in connection with the cutting head, a rotary actuator in connection with the cutting head, a cutting fluid pump, a mechanism for mixing a fluid and an abrasive to form the abrasive cutting fluid, and reservoirs for storing the abrasive cutting fluid or for storing a fluid and the abrasive separately.

Description:
[0001]     This application is a Continuation-in-Part of U.S. patent application Ser. No. 11/380,690, filed Apr. 28, 2006. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates in general to wellbore operations and more particularly to systems and methods for cutting tubulars in a wellbore.  
       BACKGROUND  
       [0003]     At various stages in a well&#39;s life it may be necessary to cut the tubulars used in its construction. This may be required during completion of the well, operation of the well or upon abandonment of the well. Reasons for cutting the pipe include without limitation, cutting a tubular that is stuck in the wellbore, cutting a window for side tracking the present wellbore and cutting fluid pathways.  
         [0004]     Prior art methods for making radial cuts include explosive jet cutters, chemical cutters and mechanically cutting with drill pipe or coiled tubing. Each of this mechanisms and methods have drawbacks. For example, with regard to explosive cutters, it is difficult to create clean cuts and to not damage material behind the cut. Additionally, health and safety concerns dictate strict operational procedures be employed when utilizing explosive cutters. With regard to chemical cutting tools, the cut depth is limited by the nature of the system and the completion. With regard to mechanical cutting, when performed using drill pipe or coiled tubing the use of a rig is required; thus increasing time loss and expenses.  
         [0005]     Therefore, it is a desire to provide a cutting tool and method for creating various types of cuts in a tubular that address drawbacks of the prior art systems and methods. It is a further desire to provide a cutting tool and method for making radial cuts as well as window cuts in a tubular. It is a still further desire to provide a cutting tool and method for creating various cuts in a tubular via a wireline.  
       SUMMARY OF THE INVENTION  
       [0006]     Accordingly, a cutting tool and method for creating a continuous cut in a tubular that is positioned in a wellbore is provided.  
         [0007]     An embodiment of a cutting tool, positionable in a tubular for creating a cut in a tubular, includes a body securable within the tubular and a cutting head having a nozzle for discharging a pressurized cutting fluid, wherein the cutting head is rotationally and axially moveable relative to the body. The cutting tool may further include one or more of a positioning mechanism, a linear actuator in connection with the cutting head, a rotary actuator in connection with the cutting head, a cutting fluid pump, a mechanism for mixing a fluid and an abrasive to form the abrasive cutting fluid, and reservoirs for storing the abrasive cutting fluid or for storing a fluid and the abrasive separately.  
         [0008]     An embodiment of a method of creating a continuous cut through a tubular that is disposed in a wellbore includes the step of positioning a tool in the tubular, the tool having a nozzle for discharging a pressurized cutting fluid that penetrates and cuts the tubular, discharging the cutting fluid creating an initiation point of a cut through the tubular, extending the cut from the initiation point along a first path, and completing the cut.  
         [0009]     A further embodiment of a method of creating a continuous cut through a tubular that is disposed in a wellbore includes the step of providing a cutting tool including a positioning mechanism, an anchoring mechanism, a linear actuator, a rotary actuator, a cutting fluid pump and a cutting head having a nozzle for discharging a pressurized cutting fluid that penetrates and cuts the tubular; positioning the tool in the tubular; securing the tool in the tubular; discharging the cutting fluid creating an initiation point of a cut through the tubular; extending the cut from the initiation point along a first path via at least one of the actuators; and completing the cut.  
         [0010]     An embodiment of completing the continues cut includes continuing the cut past the initiation point along the first path to a termination point and then traversing the cut across the first path.  
         [0011]     The foregoing has outlined the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The foregoing and other features and aspects of the present invention will be best understood with reference to the following detailed description of a specific embodiment of the invention, when read in conjunction with the accompanying drawings, wherein:  
         [0013]      FIG. 1  is a schematic of an embodiment of an abrasive jet cutting tool of the present invention;  
         [0014]      FIG. 2  is an illustration of a linear-radial cut created in a tubular utilizing an abrasive jet cutting tool of the present invention;  
         [0015]      FIG. 3A  is a an illustration of a non-linear cut utilizing an abrasive jet cutting tool of the present invention to create a window in a tubular; and  
         [0016]      FIG. 3B  is an illustration of the completion of the cut of  FIG. 3A .  
     
    
     DETAILED DESCRIPTION  
       [0017]     Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.  
         [0018]     As used herein, the terms “up” and “down”; “upper” and “lower”; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements of the embodiments of the invention. Commonly, these terms relate to a reference point with the surface from which drilling operations are initiated being the top point and the total depth of the well being the lowest point.  
         [0019]      FIG. 1  is a schematic drawing of an embodiment of an abrasive jet cutting tool of the present invention, generally denoted by the numeral  10 . The cutting tool  10  is positioned within a tubular  12  disposed in a wellbore  14  to create a cut  34  in the tubular  12 . As will be described in detail herein, the method and system of the present invention can provide linear and non-linear cuts in a tubular  12 .  
         [0020]     The cutting tool  10  of the present embodiment includes a positioning module  16 , a linear actuator  18 , a fluid pump  20 , and a cutting unit  22 . The fluid pump  20  further comprises a fluid chamber  21 . In some embodiments, the fluid chamber  21  further comprises a filter. In such embodiments, well fluids are drawn into the fluid chamber  21  and filtered for contaminants until suitable for use in the cutting unit  22 . In alternate embodiments of the fluid chamber  21 , where the existing well fluids are not suitable for use in the cutting unit  22 , the fluid chamber  21  comprises one or more fluid carriers to allow for the cutting fluid to be carried to the cutting depth from surface.  
         [0021]     The cutting unit  22  of the cutting tool  10  further comprises a high pressure pumping system  24 , an abrasive fluid feeder  26 , and a rotary cutting head  27 . The rotary cutting head  27  comprises a nozzle  42  for discharging the cutting fluid. Movement of the cutting head  27  is provided by a linear actuator  10  and a rotary actuator  46  functionally connected to the cutting head  27 .  
         [0022]     The cutting tool  10  is connected to a conveyance means  28  via a head  30 . In the embodiment illustrated, the conveyance means  28  is shown as a wireline; however, other conveyance means including, without limitation, coiled tubing may be utilized. The tool  10  may further include an anchor  32  for securing the tool  10  within a tubular  12 .  
         [0023]     During completion or operation of the well, it may be desired or necessary to cut a tubular  12  in a region  36 . For example, it may be desired to remove a portion of a tubular  12  when it has become stuck in the wellbore  12  during completion or for plugging and abandonment operations. When a portion of a tubular  12  is to be removed, the tool  10  may be used to create a continuous, linear cut  34   a  ( FIG. 2 ) radially through the tubular  12 . In another example, it may be desired to create an opening or window  38  ( FIG. 3A ) in a tubular  12  to kick-off from the wellbore  14  or to provide a port for fluid ingress or egress. The window  38 , of any geometric shape, may be formed by making a continuous non-linear cut ( 34   b ) with the tool  10 .  
         [0024]     To make a cut  34  in a tubular  12 , the tool  10  is run into the wellbore  14  and the tubular  12  via a conveyance means  28  and positioned proximate the region  36  of interest. The cutting tool  10 , and more specifically the cutting head  27 , may be positioned utilizing the positioning module  16 . The positioning module  16  may include various electronics, including without limitation, telemetry equipment and a casing collar locator. Upon positioning the tool  10  in the desired location, the anchor  32  may be actuated to secure the tool  10  within and to the tubular  12 . It is desirable to secure the cutting tool  10  so that the tool  10  resists movement in response to the cutting operations facilitating a more accurate and continuous cut.  
         [0025]     The linear actuator  18  provides movement of the cutting head  27  and the nozzle  42  axially, as shown by the line “XX”, relative to the tool  10  and the tubular  12 . The axis “XX” represents both the longitudinal axis of the tool  10  and of the tubular  12  proximate the region  36  of interest. The rotary actuator  46  facilitates rotary motion of the cutting head  27 , as indicated by the arrow  48 , about the longitudinal axis “XX.” Plane “YY” extends substantially perpendicular to axis “XX.” 
         [0026]     As discussed above, in some embodiments of the present invention, a fluid may be stored and carried within the fluid chamber  21  and then mixed with an abrasive from the feeder  26  to form the abrasive cutting fluid  44 . The cutting fluid  44  is discharged through the nozzle  42  via the high pressure pumping system  24  for cutting the tubular  12 . In alternate embodiments, the abrasive cutting fluid  44  may be pre-mixed and carried by the tool  10 . The operation of the fluid pump  20 , cutting unit  22  and actuators  18 ,  46  may be controlled via signals communicated by telemetry or through the conveyance means  28  to the positioning module  16 . The positioning module,  16  including control electronics, is in functional connection with the cutting unit  22 .  
         [0027]      FIG. 2  is an illustration of a radial cut  34   a  created in a tubular  12  utilizing the cutting tool  10 . With reference to  FIG. 1 , a method of creating a linear, radial cut  34   a  is described. The cutting tool  10  is positioned within the tubular  12  with the cutting head  27  positioned within the region  36  of interest. The anchor  32  is actuated to extend its arms  50  to engage the tubular  12  and stabilize the tool  10 . The cutting unit  22  is energized, mixing the abrasive and fluid as cutting fluid  44  which is discharged via the pumping system  24  to initiate a cut  34   a . The linear actuator  18  is maintained in the static position and the rotary actuator  46  is actuated to rotate the cutting head  27  to create a linear radial cut  34   a . As is readily recognized, a linear, axial cut (along the axis “XX”) may also be made by maintaining the rotary actuator  18  in the static position and activating the linear actuator  32  to move the cutting head  27  axially. A method for completing cut  34   a  is illustrated in  FIG. 3B .  
         [0028]      FIG. 3A  is an illustration of a non-linear cut  34   b  created in a tubular  12  utilizing the cutting tool  10  of  FIG. 1  to form a window  38 . The window  38  may be formed in any geometric shape by forming a continuous, non-linear cut  34   b . A non-linear cut is made by utilizing the linear and the rotary actuators  18 ,  46  in combination to move the cutting head  27  along the desired path for the cut  34   b.    
         [0029]      FIG. 3B  is an exploded view of a cut finalization step  52  to create and complete a continuous cut  34 . For example, in  FIG. 3A  it is desired create a window  38  and then to cleanly remove it from the tubular  12 . This requires that the cut  34   b  be continuous. In  FIG. 2 , it is desired to remove the top portion of the tubular  12  from the wellbore  14 ; thus, it is necessary to complete a continuous cut  34   a.    
         [0030]     The continuous cut  34  is illustrated by the dashed line in  FIG. 3B . The cut  34  is started at an initiation point  54  and proceeds in the direction of arrow  1 . Desirably, the cut  34  is continued until it connects to the initiation point  54 . However, due to miscalculations or movement of the tool  10 , the cut  34  may not meet the initiation point  54  resulting in a non-continuous cut. To avoid an incomplete cut, the cut  34  is continued in the direction  2  to a termination point  56 . The termination point  56  is located along the cut  34  past the initiation point  54 . At the termination point  56 , the cutter head  27  is moved substantially perpendicular, shown by arrow  3 , to the previous direction of movement shown by arrows  1  and  2 . In this manner, it is ensured that a continuous cut  34  is completed.  
         [0031]     From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a system and method for creating linear and non-linear cuts through tubulars in a wellbore that is novel has been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow.