Abstract:
An anchor system including a housing having a radial opening therein. A piston disposed within the housing and translatable therein. A slip in operable communication with the piston such that translation of the piston axially of the housing causes movement of the slip radially of the housing. The slip having a contact face that is nonparallel to an axis of the housing and nonparallel to a surface against which the slip is configured to be set. A method for anchoring a tool is included.

Description:
BACKGROUND 
     In the downhole drilling and completion industry it is often necessary to place tools in a selected position within a borehole, cased or open, for various purposes. To locate and anchor such tools in the selected position the art has known many different forms of securement each of which has inherent benefits and weaknesses. Selection of one of the many forms of securement is within the purview of the designer for the ultimate system and takes into account one or more parameters of the environment, operating conditions, etc. in the intended location. 
     One common form of anchoring system uses a plurality of “slips” that are urged radially outwardly by a conical ramp on a mandrel to engage an inside surface of a borehole in which the anchor is to be set. Tools are reliably centered in the borehole using this anchoring configuration. 
     In view of the nearly endless possible situations in which tools may need to be anchored, the art is always receptive to new anchoring arrangements. 
     SUMMARY 
     An anchor system including a housing having a radial opening therein; a piston disposed within the housing and translatable therein; and a slip in operable communication with the piston such that translation of the piston axially of the housing causes movement of the slip radially of the housing, the slip having a contact face that is nonparallel to an axis of the housing and nonparallel to a surface against which the slip is configured to be set. 
     A method for anchoring a tool with a positional bias including attaching a tool to an anchoring system having a slip with a contact face that is nonparallel to a surface against which it is to be set; deploying the slip at a target location in a borehole; and causing an uphole end of the tool to be biased against a selected portion of the borehole, the portion being related to the orientation of the slip and the contact face of the slip. 
     A method for anchoring a tool with a positional bias including attaching a tool to an anchoring system having a slip with a contact face that is angled relative to an axis of the tool and anchoring system; deploying the slip at a target location in a borehole; causing an uphole end of the tool to be biased against a selected portion of the borehole, the portion being related to the orientation of the slip and the contact face of the slip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
         FIGS. 1 and 2  are together an extended view of an anchor system and tool; 
         FIG. 3  is an end view of the anchoring system of  FIG. 2  taken along line  3 - 3 ; 
         FIG. 4  is an end view of the anchoring system of  FIG. 2  taken along line  3 - 3  in an alternate orientation; 
         FIG. 5  is an end view of the anchoring system of  FIG. 2  taken along line  3 - 3  in another alternate orientation; and 
         FIG. 6  is a cross-sectional view of a unidirectional configuration between a piston and housing of the anchoring system. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2  simultaneously an anchor system  10  is illustrated. A tool  12  (illustrated as a Whipstock but not limited thereto) is attached to the system  10 . The anchor system  10  and tool  12  are illustrated in a set position. The anchoring system  10  includes a housing  14  of a tubular nature, the housing including a radial opening  16  positioned to allow radial translocation of objects or fluid through a wall of the housing. The housing  14  further includes a contact surface  15  having a gripping configuration  17 , which may comprise wickers, bumps, roughness, etc. 
     Within the housing  14  is disposed a piston  18  having an angled wedge face  20 . A slip  40  is also at least partially disposed within the housing, the slip  40  having an angled wedge follower face  42  complementary to and in communication with face  20 . The piston  18  includes at an outside dimension surface  22  thereof a unidirectional configuration  24  such as a wicker thread or wicker follower with the other of the wicker thread or wicker follower being disposed upon an inside dimension surface  26  of the housing, for example, as shown in  FIG. 6 . The wicker thread and wicker follower or other similar configuration work together to permit movement of the piston  18  in one direction  23  relative to the housing  14  thereby preventing movement in the opposite direction  25 . The wicker thread and wicker follower in that embodiment ratchet past each other in one direction  23  and cannot move relative to one another in the other direction  25 . Further the piston includes a seal configuration  28  that interacts with the housing surface  26  to prevent fluid moving between the piston  18  and housing  14 . An end of the piston  18  is closed forming a piston crown  30  that along with the housing  14  defines a chamber  32  that may be changed in volume through the application of fluid pressure and the consequent movement of the piston  18  toward the slip. An inlet  34  is provided into the chamber  32  for the introduction of fluid at a selected time related to deployment of the anchor  10 . 
     During run in, the slip  40  is disposed at the angled wedge face  20  of the piston  18 . Although the slip is illustrated in the set position, it is evident what the position of the slip is in the run in position from the relative positions of the portions of the release member  43 / 44  that are seen in this view as parted. Release member  43 / 44  is a single configuration in the run in position affixing the slip  40  to the piston  18 . The release member may be a shear member and dictates the position of the slip during run in. 
     The slip  40  itself includes a contact face  46  intended to extend into contact with a casing  47  or open hole. The face  46  is specifically configured to be angled relative to a surface against which it is to set and/or nonparallel to an axis of the housing  14 . It is to be understood that these two conditions can occur in the same embodiment. This is illustrated in  FIG. 2  since the downhole end of the slip at point  49  is in contact with the casing  47  and the uphole end of the slip at point  51  is not in contact with the casing  47 . This is particularly distinct from prior art slips in that prior art slips would have contact faces that are intended to be parallel with the casing or open hole and are parallel to an axis of the anchor of which they form a part. The angle of the contact face to an expected interfacing surface is to be within a range of about 1 degree to about 10 degrees. In alternate embodiments the angle of the contact face to an axis of the housing is to be within a range of about 1 degree to about 10 degrees. 
     The slip  40  further includes an angled downhole end  48  that is interactive with a downhole end  50  of the opening  16 . The end  50  includes a chamfer  52  as shown. This configuration assists in the reduction of friction between the slip  40  and the opening  16 . As will be appreciated by one of skill in the art from the foregoing and a view of  FIG. 2 , a significant amount of force will exist between the slip and the downhole end of the opening  16  due to the downhole direction urging of the piston  18 . Creating the chamfer  52  and the angled downhole end  48 , will change the vector at which the urging from the piston  18  impacts the subject interface (between the opening and the slip) and hence reduces the effective frictional bind that would otherwise occur thereby reducing the amount of fluid pressure required to be delivered to chamber  32  in order to set the anchor system. 
     Operation of the device, system and tool, comprises attaching the tool  12  to the anchor system  10  at a thread  60 . Orientation of the tool  12  to the anchor system  10  is adjusted using a spacer  62  interposed at the thread  60  such as a washer. One of skill in the art will understand that a washer interposed in a threaded connection will cause the threaded connection to be engaged to a different degree than it would be without the washer or spacer and hence an orientation of one end of the threaded connection to the other end of the threaded connection is adjustable by the thickness of the spacer. The degree to which orientation changes with various thicknesses of spacers is related to the pitch of the thread used. In one embodiment, the thread is an acme type thread and spacers used will be of a range of thicknesses depending upon the number of degrees of rotational orientation from fully threaded that is desired. In an exemplary embodiment, the degree of orientation change is related to the thickness of the spacer as 180 degrees of rotation per .188 inch of thickness. 
     Once the desired orientation of the tool  12  to the anchor system  10  is achieved through selection and installation of the appropriate spacer  62 , the entire assembly is run in the hole to target depth. Upon reaching target depth fluid is pressurized to expand chamber  32  by urging piston  18  downhole toward the slip  40 . As piston  18  moves, the release member  43 / 44  is loaded substantially in shear and will shear at a preselected value. After the member  43 / 44  shears, the slip will move radially outwardly of the housing  14  through the opening  16  based upon the angled surface  20  interacting with the angled wedge follower face  42 . This continues until the slip contact face  46  seats against casing  47  or the open hole and fluid pressure builds at surface to indicate that the set is complete. 
     Due to the angle of the contact face  46  as disclosed, the tool  12  attached to the anchor system  10  will be biased to one surface of the casing  47  or open hole. More specifically, the slip  40  contact face  46  will “want” to flatten out against the casing  47  or open hole and assume a parallel position thereagainst. Since it cannot easily do this due to the angle of the contact face  46 , the impetus to do so must be transmitted to another part of the assembly. This part will be the uphole end of the tool  12  connected to the system  10 . 
     Because the anchor system can be oriented relative to the tool  12 , the direction of bias can be controlled and put to advantage. As illustrated in  FIGS. 1 and 2 , it can be seen that where the slip is oriented to extend on the same side of the whole assembly that the back of the Whipstock is on, the back of the Whipstock is urged against the casing  47 . More specifically and referring to  FIGS. 1 and 2 , and further assuming for purposes of explanation and clarity only (no limitation is to be inferred) that the casing  47  happens to be in a horizontal borehole so that the reader is able to easily place the figures side by side and view them as numbered, the slip  40  extends from the housing  14  downwardly and the Whipstock is oriented with its face upwardly. The angle of the contact face  46  of the slip  40  will cause the uphole end  64  of the tool  12  (Whipstock here) to be tightly urged against the casing  47  on the same side as the slip  40  is on. In the example set up for the readers benefit, the end  64  is at the bottom of the drawing since the slip is at the bottom of the drawing but of course the system and tool could be oriented to be biased toward the top of the casing as viewed in the drawings. This is important particularly in the case of an actual highly deviated or horizontal borehole as it is sometimes of interest to a well operator to create a “low exit” which in the vernacular means that the operator wants to mill a window in the side of the casing that is lower using gravity as a reference. Problems with the prior art will allow the end  64  of the Whipstock for example to tend to sag with gravity and get in the way of the mill that is to be used after setting of the anchor and tool. This can create problems for the operator. In the anchor system  10  as disclosed herein however, the end  64  can be biased securely to the side of the casing or open hole that is opposed to gravity because of the action of the contact face  46  of the slip. In a situation as described the anchor  10  and tool would be rotated substantially 180 degrees from the position shown in  FIGS. 1 and 2  so that the slip  40  would extend upwardly in the drawing and the Whipstock end  64  would be at the top of the drawing against casing  47 . 
     Because the slip  40  can be oriented as desired relative to the tool  12  as discussed above, an uphole end  64  of whatever tool  12  is used can be biased in any direction that is desired. The orientation configuration is illustrated with three other views of the slip from a downhole end of the system  10  in  FIGS. 3-5 . 
     It is noted that although a fluid pressure configuration is illustrated, the anchor system  10  can be actuated with other means such as a lead screw, set down weight, explosive devices, etc. 
     While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.