Abstract:
A subterranean well tool which is manipulatable by a control mandrel between run-in and set positions within a wellbore having casing includes an assembly which provides a selectively operable lock to prevent premature activation of the assembly from the run-in position towards the set position until a predeterminable compressive load is carried through the well tool by the control mandrel to manipulate the assembly from a first initial position to an intermediate position and thereafter to a final extended position.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention pertains to an apparatus and method for anchoring a subterranean well tool within a wellbore having casing. 
     (2) Description of the Prior Art 
     Subterranean well tools, such as packers, bridge plugs, tubing and other hangers, safety valves, fishing tools, and the like, typically are run into a well subsequent to casing being set and cemented into place. It is desirable to set such tools in the well along the casing against movements in at least one direction, such as against movements toward the top or bottom of the well, rotational movements, or any combination of such movements. Therefore, most such tools are provided with an anchoring assembly. The anchoring assembly is moved from a run-in position when the tool is being run in the well through the casing to the desired depth or location at which it is predetermined to be set and anchored in position. The anchoring means typically expands radially outwardly from the tool such that the anchor can grasp the outer wall of the casing, such as by teeth or otherwise, to prevent any such movements thereafter. Of course, it is extremely important that any such anchoring assembly included with any such subterranean well tool not be manipulatable between the run-in position to the set position, or there between, at any time that the well tool is being run into the well, or actuated in the well, prior to the time that it is determined to be anchored within the well, either for permanent setting of the well tool or temporary setting and withdrawal after a particular operation within the well has been effected. Any such premature actuation of the anchoring assembly could result in a failure of the tool to thereafter properly set at the desired location at the desired time, and, in dramatic instances, could result in the well tool, or other tool, becoming stuck in the well, necessitating a time consuming and otherwise expensive fishing operation to retrieve the well tool. 
     The present invention addresses the deficiencies in prior art devices, as generally described above. 
     SUMMARY OF THE INVENTION 
     The present invention provides an assembly such as in an anchoring assembly, and method of use, in which the assembly is combined with a subterranean well tool manipulatable by a control mandrel between a run-in and set position within a wellbore having casing. The subterranean well tool may be a packer, bridge plug, safety valve, tubing or other hanger, cementing tool, or any other tool typically known and utilized by those skilled in the art of subterranean well tools. The control mandrel may be directly connected to tubing, such as a drill string, workover string, or the like, extending to the top of the well, which may be rotated, or activated by push/pull technique. Alternatively, the mandrel may be operated by a setting or other tool activated pneumactically, hydraulically, electrically, or mechanically. 
     The assembly may have at least one housing member, and, preferably, may have upper, central and lower housing members. These housing members may be vertically aligned with respect to one another. The control mandrel extends through at least one of the housing members and may extend through all of such members by means of a bore which is defined through the housing members. Support means, such as a series of outwardly pivotal supporting finger or supporting elements are shiftably movable between initial and intermediate positions wherein the support elements or finger elements are in a retracted condition relative to the housing member, or all housing members, if more than one housing member is provided. The support members or finger elements may be moved to a final, extended position when the well tool is in the set position. The support member or finger elements may be radially disposed around the exterior of a housing member, such as the central housing member, if a plurality of housing members are provided, as described below. 
     Each of the support members a finger elements have first and second ends, with the first end of the support member, or finger elements, preferably, being joined relative to a housing member to permit outward pivotal movements between the intermediate position and the final, extended position. Means, such as one or more platforms, are pivotally secured to the second end of the support member and moveable by the support member from a position of substantial vertical radial alignment with a central housing to a horizontal alignment position with a housing member or members. Anchoring elements are provided on the platform for anchoring the combination to the casing in the set position against movements in at least one direction, or, preferably, any direction. The anchoring elements may include a series of radially extending wicker teeth which are etched or otherwise machined or profiled an outboard area of one or more of the platforms. 
     The assembly of the present combination has particular utility when the well tool includes components which are activatable by and require a compressive force therethrough for effective setting against the smooth inner wall of the well casing. For example, the mechanism has particular utility when combined with a subterranean well tool including an expandible, compressible elastomeric packer element and means for preventing extrusion of the packer element. For example, the present invention has particular utility when incorporated into the well tool of co-pending U.S. patent applicable entitled “High Expansion Elastomeric Plug”, filed on May 11, 1999, and assigned U.S. Ser. No. 09/309,699, and, especially, in an embodiment generally illustrated FIGS. 13 and 14 of said application. 
     In the method of the present invention, the combination well tool and assembly is secured to a control mandrel, which may, in turn, be operatively associated with an actuating tool such as that disclosed in co-pending U.S. Patent Application entitled “Electrically Actuated Setting Tool”, U.S. Ser. No. 09/309,698, filed May 11, 1999. Thereafter, the combination is lowered into the well to a position in which it is desired that the combination be anchored against the well casing. A first compressive load is transmitted through the combination by means of the mandrel to initiate activation of the well tool, such as by applying a compressive force to a well packer component, thence to an anti-extrusion component. As continued compressive force is applied through the mandrel, such as by applying a pulling force through the mandrel, the well packer component is set without the support member, or preferred finger elements, of the anchor assembly, being moved from the initial position. Thereafter, an increased compressive load is applied through the mandrel whereby the supporting member, or finger elements, are moved to an intermediate position, but the support element still is in a retracted condition relative to the housing member and the casing. In the intermediate position, the support element, or finger elements if utilized, are “unlocked” and are activated for subsequent movement from the intermediate position to the final extended position. The final extended position of the supporting element is effected by continued upward pull of the mandrel, again applying even more compressive force through the combination, causing the supporting member to pivot or flex outwardly to, in turn, permit anchoring elements to grasp the inner wall of the casing such that the combination is anchored against movement in at least one direction. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A and 1B together constitute a longitudinal partial cross-sectional view of the anchor assembly in combination with a subterranean well tool, such as a packer and an extrusion resistor, all illustrated in the “run-in” position. 
     FIGS. 2A and 2B are views similar to that of FIGS. 1A and 1B, illustrating the combination with the anchor assembly in the intermediate position. 
     FIG. 3 is an enlarged cross-sectional view of the combination in the final, or set position. 
     FIG. 4 is a perspective view of the preferred sleeve mechanism and central housing of the anchor assembly of the present invention in the “run-in” position. 
     FIG. 5 is a perspective view similar to that of FIG. 4, illustrating the anchor assembly components in the intermediate position. 
     FIGS. 6A-6F together constitute a series of enlarged cross-sectional illustrations of a portion of the platform assembly illustrated in FIG.  3  and particularizing the configuration of the angled, or semi-circular, teeth elements providing a universal anchoring mechanism for anchoring the apparatus in any one of a number of varying internal diameter casings or other conduits. 
     FIG. 7 is an enlarged cross-sectional view of the teeth arrangement of a universal anchoring mechanism showing the angled teeth in an alternate preferred form in multiple plains. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Now with respect to the drawings, the present invention provides an anchor assembly  100  which includes an upper housing  10 , a central housing  11  there below and a lower housing member  12 . Each of the housing members  10 ,  11  and  12  have a central bore  10 -A,  11 -A and  12 -A for receipt there through of a control mandrel M. A series of elongated finger elements  13 ,  14 ,  15  and  16  are secured to the central housing  11  at first ends  13 -A,  14 -A,  15 -A and  16 -A. A groove  13 -C,  14 -C,  15 -C and  16 -C is provided through each of the ends  13 -A,  13 -B,  13 -C and  13 -D for receipt of a circumferentially extending ring element  27  through the upper finger members  13  and  14 , and a similarly constructed ring element  27 ′ in the lower set of fingers  15  and  16 . 
     Each of the fingers  13 ,  14 ,  15  and  16  have a second end  13 -B,  14 -B,  15 -B and  16 -B which are respectively secured to platform member  17 ,  18 ,  19  and  20  by means of pivot pins  17 -B,  18 -B,  19 -B and  20 -B. In turn, the platform  17  is secured to the upper housing  10  by means of a retaining metal pin  22  disposed through a groove  21 . Likewise, the platform  18  also is operatively secured relative to the upper housing  10  by means of a similar retaining pin  22  received in the platform  18  through a groove or bore  21 . Similarly, the lower platforms  19  and  20  each are secured to the lower housing  12  by means of a retaining pin  24  retained within a groove  23  through each of the platforms  19  and  20 . 
     Each of the platforms  17 ,  18 ,  19  and  20  have a series of teeth  17 -A,  18 -A,  19 -A and  20 -A profiled, such as machining, or the like, around and on the outboard-most end of the respective platform  17 ,  18 ,  19  and  20 , for grasping engagements with the smooth inner wall C- 1  of the casing C within the well W, when the anchor assembly  100  is shifted to the set, or final, position. 
     The well tool WT of the present invention comprises the anchor assembly  100 , an elastomeric packer EP of known construction, and an anti-extrusion mechanism AE. The elastomeric packer EP and/or the anti-extrusion mechanism AE may be one of a number of designs well know to those skilled in the art and, preferably, may be of the design illustrated in co-pending U.S. application Ser. No. 09/309,699, filed May 11, 1999 and entitled “High Expansion Elastomeric Plug.” 
     Now, as particularly shown in FIGS. 4 and 5, the anchoring mechanism  100  further includes a sleeve  25  consisting of upper and lower cylindrical sleeve members  25 -A and  25 -B, around the exterior of the mandrel M. The upper sleeve member  25 -A includes first and second H-leg elements  28 -A and  28 -B bridging each of the fingers. The H-leg elements  28 -A and  28 -B have defined there between a slotted grooveway  26  with and open lower end  26 -A. A metallic ring  27  passes through a groove, such as groove  13 -C in finger  13 , and in all of the fingers, to secure the fingers together and within the cylindrical sleeve member  25 -A. A similar metallic ring  27 ′ passes through grooves, such as  15 -c and  16 -c in each of the fingers  15  and  16 . 
     The central housing  11  has a series of circumferentially extending receiving profiles  28  for receipt of the fingers, such as  13  and  14  when the anchor assembly  100  is shifted to intermediate and set positions. 
     Each of the upper finger elements, such as  13  and  14 , have defined around their exterior a groove way  29 -A- 1  for housing of a backup wire retainer  29 -A therein. Likewise, the lower fingers, such as  15 , and  16  also have a groove way  29 -B- 1  for receipt of another backup wire retainer  29 -B. Each of the wire retainers  29 -A and  29 -B serve to further assure inadvertent premature shifting of the fingers,  13 ,  14 ,  15  and  16  from the run-in, or initial, position, toward the set position prior to the time that it is desired to actually anchor the well tool WT. The backup wire retainers  29 -A and  29 -B will shear, or otherwise break, or part, to permit expansion of the fingers  13 ,  14 ,  15  and  16  as the fingers are urged pivotally outwardly from the intermediate position to the set position. 
     Each of the sleeve members  25 -A and  25 -B are secured to the respective fingers by means of a shear pin  30 ,  31 ,  32  or  33  received in a opening  33 -A,  32 -A,  31 -A and  30 -A, respectively. As the mandrel M is shifted, for example, upwardly, relative to the well tool WT, a compressive load is defined through the well tool WT and the shear pins  31 ,  31 ,  32  and  33  shear, separating the upper and lower sleeve members  25 -A and  25 -B from initial engagement with the respective finger elements to permit the fingers to move from the initial position to the intermediate position. As the anchor  100  is moved to the intermediate position, the upper fingers  13  and  14  will move downwardly such that their lower most end will be snugly engaged within the receiving profiles  28  of the central housing  11 . Likewise, the lower fingers  15  and  16  will have their upper most ends shifted into companion receiving profiles in the lower sleeve member  25 -B on the opposite face of the central housing  11 . 
     Now with specific reference to FIGS. 6A-6F there is illustrated the platform  18  with a series of semicircularly configured teeth elements thereon for grasping into the inner wall C- 1  of a casing C. The configuration, as shown, for the teeth elements provides for universal ability for a device of only one size to be set within one of a number of internal diameter sized casing or other tubular strings within the well W. The platform  18  is shown with a grasping teeth configuration  18 -A having a series of peaks  18 -A″ and valleys  18 A″ spaced there between. Such teeth  18 -A may be machined onto the platform  18  in any one of a number of ways known to those skilled in the art. The outermost edge of the peaks  18 -A′ forming the teeth  18 -A define a radial line  50  which has a first external point of curvature  51  at one end, i.e., the uppermost end, and a second external point of curvature  52  at the other end, which will be somewhat outwardly extending from the first external point of curvature  51 . The second external point of curvature is larger than the first external point of curvature and the radial line  50  has an external point of curvature continuous from the first end  51  to the second end  52 . 
     As shown in FIG. 6A, when some of the peaks  18 -A′ of the teeth configuration  18 -A adjacent the second external area  52  contact the inner wall C- 1  of the casing C, continued movement of the platform  18  is resisted and the actuation energy defined through the mandrel M to the apparatus  100  is transferred through the teeth  18 -A into the inner wall C- 1  as the teeth  18 A begin to grasp and engage such inner wall. Peaks  18 A′ defined on the platform  18  along the radial line  50  which are not of a companion external diameter do not contact or grasp the inner wall C- 1 , but satisfactory anchoring engagements are provided by means of the peaks  18 -A 1  that do come into contact with and are driven into the inner wall C 1  of the casing C. 
     Likewise, FIG. 6B illustrates additional movement of the platform  18  from the position shown in FIG. 6A when the inner wall C 1  of the casing C has a smaller internal diameter than the casing C shown in FIG.  6 A. As shown in FIG. 6B, more of the peaks  18 -A′ are driven into the inner wall C 1  of the casing C due to the size differentiation from that of the casing C shown in FIG.  6 A. Likewise, as shown in FIG. 6C, a more central portion of the peaks  18 -A′ are driven into the inner wall C 1  in instances in which the apparatus  100  is desired to be set within sized casing smaller than that shown in FIG.  6 B. In this instance, it will be noted that some of the peaks  18 -A′ adjacent the enlarged end  52  along the radial line  50  of the platform  18  may not come into partial or complete grasping contact with the inner wall C 1  of that sized casing C because of the semi-circular radial configuration of the teeth  18 A along the line  50 . 
     FIG. 6D shows the anchoring engagement of the apparatus  100  along the more central portions of the peaks  18 -A 1  of the teeth  18 A in casing smaller than as shown in FIG.  6 C. Again, because of the configuration of the radial line  50  between the ends  51  and  52 , forming a semi-circular configuration, the peaks  18 -A′ at the upper most end of the teeth configuration and those at the lowermost end of the teeth configuration will not come into anchoring engagement with the inner wall C 1  of the casing C. 
     FIG. 6E shows the positioning of the apparatus  100  and the teeth  18 -A in even smaller sized internal diameter casing C. Here, many of the peaks  18 -A′ below the approximate middle point between the first and second ends  51  and  52  may not come into contacting engagement with the inner wall C 1  of the casing C, yet there is sufficient grasping engagement between the teeth  18 A and the innerwall C 1  for satisfactory anchoring purposes. 
     Finally, FIG. 6F shows the positioning of the platform  18  relative to the teeth  18 A in the smallest sized casing such that the peaks  18 -A′ along the uppermost internal curving end  51  of the platform  18  provide the grasping engagement of the inner wall C 1  of the casing C, with most of the teeth there below not being in grasping engagement. 
     Now with reference to FIG. 7 an alternate preferred embodiment of the construction and design of the teeth configuration as shown in FIGS. 6A-6F is illustrated. The teeth are in a plurality of plains, such as plain  1 , plain  2  and plain  3 . A line, plain  1 , may be defined for the first plain from the first peak point  18 -A′ through the last peak point  18 -A′. Plain  2  is defined by a line  2 -X which is angularly offset a predetermined amount from the line  1 -X of plain  1  between the first, or upper, and last, or lowermost, peaks  18 A′ on the line  1 -X. Plain  2  is defined as the line  2 -X between the first peak  18 -A″ and the last peak  18 -A″ along the line  2 -X. Yet a third plain, plain  3 , is defined along the line  3 -X which is angularly offset an amount from the line  2 -X defining plain  2 . Plain  3  contains a series of teeth peaks marked  18 -A′″. Thus, setting in the largest internal diameter casing will be effected by the teeth configuration and grasping effect of the teeth along plain  3 , while the next largest internal diameter casing will engage the teeth along plain  2 , and so on. When utilizing this configuration for the teeth, a number of plains may be provided for the contemplated universal sizes of internal diameter casing for the particular application at hand. 
     OPERATION 
     The combination is made up at the top of the well and will include the well tool WT and the anchor assembly  100 . The mandrel M is inserted through each of the bores  10 -A,  11 -A and  12 -A of the respective upper, central and lower housing members  10 ,  11  and  12 , and through the anti-extrusion mechanism AE, as well as the elastomeric packer EP. The well tool WT now is run in the well to a predeterminable location within the casing C. 
     When it is desired to set the well tool WT, a first compressive force is transferred through the mandrel by means of a setting tool (not shown) to first cause anchoring of the well tool WT through activation, then sealing of the packer EP. Upward pull on the mandrel M through the setting tool causes each of the shear pins  30 ,  31 ,  32  and  33  to shear, separating the fingers  13 ,  14 ,  15  and  16  from the sleeve, or bridge,  25 . Continued, and yet additional, compressive force which is transferred through the mandrel M such as by continued upward pull, now causes the upper fingers  13  and  14  to be received within the receiving profiles  28  of the central housing  11 . The receiving profiles may be either individually contoured for each of the sets of finger, or may be of unitized, circular construction, providing a continuous profile or receiving area  28  for the sets of fingers. Likewise, and concurrently, the upper most ends of the fingers  15  and  16  are received within a similarly profiled receiving profile  28  within the lower sleeve member  25 -B. In this manner, the sleeve members  25 -A and  25 -B contract, vertically, relative to the central housing  11 , such that the “gap” defined by the receiving profiles  28 , is eliminated. The anchor assembly  100  now is moved from the initial, or run-in position, as shown in FIG. 4, to the intermediate position, as shown in FIG.  5 . 
     Thereafter, continued, additional, compressive load may be carried through the well tool W by additional pulling through the mandrel M and the setting tool to cause the backup wire retainers  29 -A and  29 -B to break due to additional expansive urging forces thereon by outward radial movements of the fingers  13 ,  14 ,  15  and  16  being transferred into the fingers by means of the joinder of the ends of the fingers within the receiving profile  27  of the central housing  11 . Subsequent to the breaking of the wire retainers  29 -A and  29 -B, the fingers  13 ,  14 ,  15  and  16  continue outward of movements toward the inner wall C- 1  of the casing C until the platforms  17 ,  18 ,  19  and  20  are shifted radially outwardly towards the casing C and become vertically disposed relative to the mandrel M. In this position, the platforms  17 ,  18 ,  19  and  20  should be at substantially a 45° angle relative to the sleeve  25  and the mandrel M. When the platforms are in the relative vertical position, as described, the teeth  17 -A,  18 -A,  19 -A and  20 -A will be caused to be imbedded within the inner wall C- 1  of the casing C to resist movements of the well tool W in at least one direction, and, as illustrated, in a plurality of directions, i.e., upwardly and downwardly. 
     As the compressive load is transferred through the well assembly  100 , by the mandrel M, the anti-extrusion component AE of the packer EP will be urged outwardly to prevent the elastomeric packer EP from extruding when the well tool WT is set along the smooth inner wall C- 1  of the casing C. Final compressive movements of the mandrel M cause the packer EP to become set within the well. 
     As described, the anchor assembly  100  of the present invention is designed to eliminate premature or inadvertent activation until the well tool WT is desired to be anchored at such time and at such location within the well W. In this manner, shock, and other forces which may be encountered during the running of the tool WT into and through the well W are not operatively transferred to the anchor assembly  100 , and/or bypassed by provision of the sleeve  25  and the “gap” or link, defined as the distance between the lower or first ends of the respective finger elements and the depth of the receiving profiles  27  within the central housing  11 . 
     The assembly  100  preferably may be used in a tool anchor device, as particularly described but may also be used in many other devices in which premature activation must be avoided, the invention providing an assembly which bridges activation forces as well as shock across a component, until needed. 
     Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this is by illustration only that the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention.