GB2032490A - Anchoring Whipstocks in Well Bores - Google Patents

Abstract

An anchor 10 is lowered in a well bore to a desired location and turned, if necessary, to point a first directional device thereon in a selected direction, after which the anchor is secured by slips 27, 39 and packing 35 against all movement. A whipstock 15, anchor means 105 and mandrel and secured together so that a second directional device on the mandrel is aligned with the whipstock. The whipstock, anchor means and mandrel combination is then lowered in the well bore, the directional devices engaging one another to turn said combination to point the whipstock 15 in the same direction as the first directional device on the anchor 10. The anchor means is coupled to the anchor by a ratchet- like threaded latch without disturbing the selected direction in which the whipstock is pointing. Finally, a cutting tool 150 is deflected by the whipstock to cut a window W in well casing 13 and/or to sidetrack the well bore. <IMAGE>

Description

SPECIFICATION Anchoring Whipstocks in Well Bores The present invention relates to well bore apparatus, and more particularly to whipstock apparatus to be anchored in the well bore to deflect one or more cutting tools, for the purpose of cutting a window in well bore casing, sidetracking the well bore, or cutting the window and also sidetracking the well bore.

In sidetracking a well bore, a cement plug or a bridge plug has heretofore been set in the well bore and a permanent whipstock set against the particular plug installed in the well bore. Reliance has been placed upon a slip to anchor the whipstock in position by applying drilling string weight to the latter. This arrangement is not dependable since the whipstock occasionally is lifted or turned by the drill string used in sidetracking the well bore. It becomes impossible to reenter the sidetracked hole with the drill string, since the whipstock has been inadvertently shifted to a position in which it is no longer oriented with the sidetracked hole.

An object of the present invention is to anchor a whipstock to a bridge plug or the like set in the well bore to prevent turn'y7g, or other shifting, of the whipstock in the bore.

A further object of the invention is to provide a whipstock anchored to a bridge plug or the like, the whipstock coacting therewith to point in a particular direction which is the direction in which a window is to be cut in the casing and the well bore sidetracked, or in which the well bore is to be -sidetracked only in the event the casing has been previously cut away by a casing mill.

According to one aspect of the present invention, apparatus for securing a whipstock in a well bore comprises an anchor, means for securing said anchor in the well bore, a whipstock, anchor means secured to said whipstock and having coupling means thereon, said coupling means being engageable with said anchor to secure said anchor means to said anchor and prevent movement of said whipstock in the well bore.

Preferably, said anchor includes a first directional device, there being means for determining the direction in which said first device is pointing, means for turning said anchor to point said first device in a predetermined direction, and said anchor securing means enabling said anchor to be secured with said first device pointing in said predetermined direction, said anchor means including a mandrel having a second directional device aligned with said whipstock, said second device being engageable with said first device to turn said mandrel, anchor means and whipstock to face said whipstock in said predetermined direction, engagement of said coupling means with said anchor allowing said whipstockto remain facing in said predetermined direction.

Protection is also sought for the manner in which the abovedefined apparatus is to be used, a method for securing a whipstock in a well bore, according to a second aspect of the present invention, thus comprising lowering an anchor into the well bore, securing said anchor in the well bore, then lowering into the well bore a whipstock secured to anchor means, and finally causing said anchor to be engaged by coupling means on said anchor means, to secure said anchor means to said said anchor and prevent movement of said whipstock in the well bore.

In a particularly preferred manner of operation, an anchor containing an orienting device is connected to a drill pipe, or other tubular string, that has an orienting sub located above the anchor and aligned rotationally with the orienting device of the anchor. After the apparatus has been lowered to the depth in the well bore at which it is to be set, a survey is taken, as by lowering a survey instrument through the drill pipe into the orienting sub, or in any other known manner, to determine the direction in which the orienting device is pointed. The driliing string is then turned a sufficient number of degrees to shift the orienting device arcuately so that it points in the direction in which a window is to be subsequently cut by a suitable casing mill, or the hole is to be sidetracked.The anchor is then set in position without shifting the direction in which the orienting device is pointing. The lower end of a whipstock is then secured to suitable anchor means, and the tapered face or deflecting surface of the whipstock is aligned with an orienting device of a mandrel which is to be moved within the anchor and into engagement with the orienting device of the anchor. This automatically turns the mandrel and whipstock to ensure that the whipstock is aligned with the orienting device of the anchor. The whipstock is then secured to the anchor to prevent its subsequent turning from the desired direction to which it has been oriented and to prevent its release from the anchor.

In the event that orientation of the whipstock is not necessary the anchor can still be run and set on a tubular string, or on a wireline, after which the whipstock can be run in the well bore and suitably secured against subsequent movement by the anchor.

Apparatus, and a method, according to the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figs. 1 a, 1 b and 1 C together constitute a combined side elevational view and longitudinal section through a well packer, bridge plug apparatus, or anchor, and a setting tool therefor located in a well bore casing, Figs. 1 b and Ic being lower continuations of Figs. 1 a and 1 h respectively; Fig. 2 is a longitudinal section illustrating the well packer anchored in packed-off condition in the well casing;; Figs. 3a, 3b, 3c and 3dtogether constitute a combined side elevational view and longitudinal section through a well packer and whipstock combination, with the parts shown in one relative position, Figs. 3b, 3c and 3d being lower continuations of Figs. 3a, 3b and 3c, respectively; Figs. 4a, 4b and 4c together constitute a combined longitudinal section and side elevational view disclosing the whipstock in its final oriented position with respect to the well packer, Figs. 4b and 4c being lower continuations of Figs. 4a and 4b respectively; and, Fig. 5 is a somewhat diagrammatic view of a milling tool deflected laterally by the whipstock to cut a window in well casing through which the bore is to be sidetracked.

As disclosed in Figs. 1 a, 1 b and 1 c, a well packer, bridge plug, or anchor 10 is secured to a suitable setting tool 11 and this combination run on a tubular string 12 to a desired depth in a well casing 13 disposed in a well bore. The tubular running string 12, setting tool 11, and packer 10 are then turned to the required extent to point an orienting device 14 (Fig. 1 c) in the well packer in a required direction. The setting tool is then suitably operated to anchor the packer in the well casing (Fig. 2). The setting tool 11 and running string 12 are then disconnected from the packer and removed from the hole.A whipstock 15, secured to an anchor means 16 and to an orienting and locking mandrel 17, are then lowered on a tubular string 1 8 in the casing 1 3 until the mandrel 1 7 is located within the passage 1 9 of the well packer, the parts then occupying the positions illustrated in Figs. 3a, 3b, 3c and 3d.

Continuing lowering of the whipstock, anchor means and mandrel shifts an orienting portion 20 of the mandrel into an appropriate relation to the packer orienting device 14, so that the concave face 21 of the whipstock faces in the required direction, which is the same direction in which the packer orienting device 14 is located or pointing, the parts then being in the position illustrated in Figs. 4a, 4b, and 4c.

As disclosed in Figs. 1 a, 1 b, and 1 c, the apparatus includes the well packer or bridge plug 10 which has a central body 22 provided with the longitudinal passage 1 9 extending therethrough.

A guide 24 is threadedly secured to the lower end of the body 22 and has one or more radial orienting pins 14 secured thereto projecting into guide passage 23a to a short extent. This guide, in turn, is threaded onto the upper end of a pup joint 25, the lower end of which is threaded into a bull plug 26 which effectively closes the lower end of the passage 19 through the packer.

A lower slip structure 27 surrounds the body, engaging the upper end of the body guide 24.

This slip structure has external teeth 28 which are to be engaged with the well casing and an internal expander surface 29 which tapers in an inward and downward direction, this tapered surface, in turn, engaging a companion externally tapered surface 30 on a lower expander 31 initially secured to the body 22 of the tool by one or more shear screws 32 threaded in the expander and received within a peripheral groove 33 in the body. The body is prevented from rotating relative to the expander 31 by a key 22b fixed in a body groove 22a and slidably fitting in an expander groove 31 a.The slip structure has circumferentially spaced weakened sections 34 therein so that relative downward shifting of the lower expander 31 within the slip structure causes the latter to break at the weakened sections into a plurality of slip elements, which are then expanded outwardly into anchoring engagement with the well casing. The upper end of the lower expander 31 bears against a packing 35 surrounding the body, the upper end of which bears against the lower end of an upper expander 36 having a tapered surface 37 inclined in an upward and inward direction.This tapered surface engages a companion internal tapered surface 38 in an upper slip ring 39 which also has weakened sections 40, so as to break into slip segments upon relative upward wedging of the upper expander 36 within the slip structure or ring, the segments then shifting outwardly into anchoring engagement with the wall of the well casing.

Initially, the upper expander 36 is releasably secured to the body 22 by one or a plurality of shear screws 41 threaded in the expander and received within a peripheral body groove 42.

The lower end of a setting sleeve 43 engages the upper end of the slip device 39, the setting sleeve being initially held in an upward position along the body by suitable shear pins 44. A split body lock ring 45 is disposed between the lower portion of the setting sleeve and the body, this ring having upwardly facing inner ratchet teeth 46 adapted to cooperate with external ratchet teeth 47 on the body, for the purpose of permitting the setting sleeve 43 to shift relatively downwardly along the body 22, but preventing return upward movement of the setting sleeve with respect to the body. The lock ring 45 can expand outwardly sufficiently to permit it to move downwardly along the body ratchet teeth.However; any tendency for the setting sleeve to move upwardly will cause cam teeth 48 in the setting sleeve to engage companion cam teeth in the lock ring to urge the latter inwardly and retain its ratchet teeth fully meshed with the body ratchet teeth.

The details of the body lock ring and ratchet arrangement are unnecessary to an understanding of the present invention. Such details are fully described in the U.S. patent No.

2,647,584.

As disclosed in the drawings, a setting assembly 11 is connected to the upper end of the body 22 for the purpose of setting the upper and lower slips 39, 27 against the casing and expanding the packing 35 into sealing engagement with the casing wall and the packer body itself. This setting assembly, per se, forms no part of the present invention being based upon the disclosure in U.S patent No. 3,208,355, to which attention is invited. As shown in the present drawings, a setting mandrel 50 has its lower end provided with a left-hand thread 51 meshing with companion internal threads 52 in the box 53 of the packer body 22.A setting sleeve 54 is slidably mounted on the setting mandrel, which has a pair of diametrically opposed longitudinally extending slots 55 through which a cross-over piece or anvil 56 extends which is connected to the setting sleeve 54 and which passes through the lower end of a piston rod 57 extending upwardly through a lower cylinder head 58 of a lower cylinder 59. The setting sleeve 54 engages the upper end of the packer setting sleeve 43 when the setting mandrel 50 has been threadedly connected to the box 53.

The lower cylinder head 58 is threadedly secured to the upper end of the setting mandrel 50 and also to the lower end of a lower cylinder sleeve 60. A lower piston 61 is piloted over and attached to the upper end of the piston rod 57, as through use of a set screw 62, and is slidable in the lower cylinder sleeve 60. Its relative downward movement in the lower cylinder sleeve 60 moves the lower piston rod downwardly, exerting a downward force on the setting sleeve 54.Reactively, the cylinder 59 is tensioned in that direction tending to pull the setting mandrel 50 upwardly the mandrel 50 being releasably connected to the body 22 of the well packer or bridge plug by the left-hand threads 51, 52. With the setting sleeve 54 exe,rting a downward force on the packer setting sleeve 43 and the mandrel 50 an upward force on the packer body 22, the setting sleeve pin 44 is first disrupted, the sleeve shifting relatively downwardly along the body to wedge the upper slip sleeve 39 downwardly of the upper expander 36 and break it at its weakened sections 40 into segments. When sufficient downward force has been exerted on the upper expander, its shear screws 41 are disrupted and the upper expander moves toward the lower expander 31 to compress the packing sleeve 35 between the expanders and expand it outwardly against the well casing.The upward force on the packer body 22 also causes the body guide 24 to urge the slip sleeve 27 and expander 31 upwardly to disrupt the shear screws 32 securing the lower expander to the body, whereupon the lower slip sleeve is disrupted at its weakened sections 34 to form segments which are expanded outwardly by the lower expander into anchoring engagement with the casing. The setting tool shifts the packer setting sleeve 43 downwardly along the body 22 and the body relatively upwardly until the upper and lower slip segments and the packing are firmly engaged with the wall of the well casing 13, the body lock ring 45 ratcheting downwardly along the body.

The setting sleeve 43 cannot move upwardly because of the coengagement between the ratchet teeth 46, 47, thereby securing the slips and packing in their outward expanded condition, which will not only prevent longitudinal movement of the well packer or bridge plug in both directions but which will prevent its rotation.

The lower piston 61 has a side seal ring or piston ring 70 on its periphery adapted to slidably seal along the wall of the lower cylinder sleeve 60. The upper end of the lower cylinder sleeve 60 is threadedly attached to an intermediate cylinder head 71 which is, in turn, threadedly secured to the lower end of an upper cylinder sleeve 72 forming part of an upper cylinder 73. This upper cylinder is threadedly secured to an upper control sub 74 threadedly connected to an upper sub 75 for securement to an orienting sub 76 attached to the tubular string 12 extending to the top of the well bore.

Disposed in the upper cylinder below its upper head, is an upper piston 77 threadedly, or otherwise suitably secured, to a tubular thrust rod or upper piston rod 78 that extends downwardly through the upper cylinder sleeve 72 and through the central bore in the intermediate head 71, the lower end of the tubular rod engaging the upper end of the lower piston 61. The upper end of the upper piston has an inlet portion 79 for allowing fluid under pressure to pass downwardly through the central passage 80 in the upper piston rod, such fluid then passing outwardly through an outlet port 81 in the lower portion of the tubular rod into the lower cylinder 59. Leakage of fluid around the upper piston is prevented by a suitable piston ring 82 mounted in its peripheral portion and slidably sealing against the wall of the upper cylinder sleeve 72.Similarly, rod packing 83 is mounted in the intermediate cylinder head 71 which is adapted to slidably seal against the upper piston or thrust rod 78.

The lower cylinder sleeve 60 has suitable bleeder ports 84 therethrough to permit the fluid in the well bore externally of the apparatus to enter the lower cylinder below the lower piston 61. Similarly, bleeder ports 85 are provided in the upper cylinder sleeve 72 to allow fluid to pass into the upper cylinder below the upper piston 77.

During lowering of the apparatus through the fluid in the well bore, such fluid can pass to the interior of the top sub 75 through a plurality of fill ports 86, fluid passing downwardly along a support sleeve 87 attached by shear screws 88 to the upper end of a control latch 89 having upper fingers 90 overlying a shoulder 91 in the control sub 74. The fluid can pass through the circumferentially spaced longitudinal slots 92 in the control latch into the interior of the control sub, then fiowing upwardly through the tubular string 12 toward the top of the well bore.

When the well packer is to be set, as described hereinabove, a suitable trip ball 93 is dropped into the tubular string and will come to rest on the upper end of the support sleeve 87, closing the passage 94 through the latter. Fluid under pressure is then exerted on the fluid in the tubular string to disrupt the shear screws 88 and shift the support sleeve downwardly to a position in which longitudinally spaced seal rings 89a on the support sleeve close off the fill ports 86, the support sleeve moving upwardly of the control latch 89 and releasing its fingers 90 from the shoulder 91.The fluid can then flow around the upper portion of the support sleeve 87 and in through ports 95 therein to the interior passage 94 of the support sleeve, and then act downwardly on the upper piston 77 and simultaneously on the lower piston 61 to shift the setting sleeve 54 downwardly, the cross-piece 56 moving downwardly in the mandrel slots 55 enabling the setting sleeve 54 to exert a downward force on the packer setting sleeve 43.

As stated above, an upward pull is exerted on the setting mandrel 50 and packer body 22 attached thereto, the well packer thus being set in the manner above described.

Further details of construction of the hydraulic setting assembly 11 with respect to its tandem cylinder and piston arrangement, and the crossover anvil, slotted mandrel, and setting sleeve will be found in U.S. patent No. 3,208,355.

The orienting sub 76 for a gyroscopic single shot survey instrument (not shown) is secured to the top sub 75 and aligned rotationally with the orienting pins 14 in the packer body guide 24.

This survey instrument is not illustrated since it is a known device, being disclosed on pages 1817 and 1818 of the 1974-75 Composite Catalog of Oil Field Equipment and Services. This orienting sub has an orienting pin 98 extending therein which is aligned with the packer body orienting pins. A survey instrument is lowered through the tubing string and a picture taken which will disclose the bearing of the pin 98, which the operator can read after removal from the tubing string to determine exactly how many degrees the orienting sub pin 98, and, therefore, the orienting packer pins 14, are removed from the desired direction.Prior to setting the well packer 10 in the well casing, the tubing string 12 is turned the appropriate number of degrees to point the orienting pins 14 in the direction in which the whipstock 1 5 is to face, whereupon the setting tool 11 is actuated to anchor the packer to the well casing against longitudinal movement and also against rotational movement.

After the packer has been set in the well casing the tubular string 12 and hydraulic setting assembly 11 are rotated to the right to unthread the setting mandrel 50 from the packer body box 53, the setting assembly then being withdrawn from the well bore.

The whipstock 1 5 (Figs. 3a-3d) includes a lower anchor section 100 and an upper section 101 which has a partially cylindrical or convex exterior 102 (Fig. 4a) and a concave tapered inner face 21. The lower end of the upper section is connected to the lower anchor section by means of a hinge pin 103. The anchor section 100 is threadedly secured to a connector 104 which is, in turn, threadedly attached to a top collar 105 threadedly secured to an anchor sub 106 having a latch sleeve 107 mounted thereon. The upper portion 108 of the latch sleeve is circumferentially continuous, the sleeve having a plurality of circumferentially spaced slots 109 opening through its lower end to provide resilient, outwardly expandable dogs 110 which are threaded.The upper side 111 of each of the threads is substantially normal to the axis of the sub, the lower side 112 of said thread being tapered in a downward and inward direction. The dogs can move downwardly along the anchor sub 106 to a limited extent because of engagement of the lower tapered ends 11 3 of the dogs with a companion tapered flange 114 of the anchor sub.

The details of construction of the anchor sub and its threaded latch are unnecessary to an understanding of the present invention, being illustrated and described in U.S. patent No.

2,737,248.

The anchor sub 106 has an extension 11 5 threadedby secured to its lower end, the lower end of this extension, in turn, being threadedly secured to an orienting and locking mandrel 1 7 having a longitudinal groove 20 therein. This mandrel terminates in a tapered face or muleshoe portion 11 8, the upper tapered surface of which has the longitudinal groove 20 opening therethrough. This mule shoe is engageable with the orienting packer pins 14, when the mandrel 17 is lowered in the packer body passage 23a, to effect a turning of the orienting mandrel 1 7 to place its groove 20 in alignment with the pins 14.

When such alignment occurs, the mandrel 1 7 can continue its downward movement in the packer passage and along the orienting pins 14. As the mandrel 1 7 turns, the whipstock turns with it, so that the center line of the concave face 21 is caused to lie in the same plane and face in the same direction as the pins 14.

Prior to lowering the whipstock and the parts depending therefrom in the well bore, the whipstock is secured to a setting tool 120 by means of a setting stud 121, the setting tool being attached to a tubular string 1 8 for lowering the whipstock 101, latch and anchor portions 107, 106 and mandrel 1 7 into the casing, the lowering continuing until the lock mandrel 1 7 and anchor sub 106 enter the packer passage 1 9. The parts continue their downward movement, the mule shoe 11 8 engaging the orienting packer pins 14 and effecting turning of the entire whipstock assembly, latch, anchor sub, and orienting and locking mandrel until the longitudinal groove 20 is aligned with the orienting pins.When such alignment occurs, with downweight being maintained on the tools, the longitudinal groove portion 20 of the orienting mandrel slides along the pins, the parts continuing to move downwardly until the latch 107 enters the packer box 53, with the top coliar 105 engaging the upper end of such box (Fig. 4b).

At this time, the latch dogs 110 will have ratcheted past the box teeth 52, and will expand inherently outwardly to fully engage the dog threads with the box threads, as shown in Fig. 46.

As disclosed in Fig. 4c, the orienting pins 14 are located well within the groove 20, engaging the sides of the groove to prevent any significant turning of the mandrel and the whipstock with respect to the anchor, bridge plug, or well packer 10. Any tendency for the whipstock 1 5, and the parts connected thereto, to move upwardly will cause the tapered expander surface 114 on the anchor 106 to engage the companion tapered surfaces on the dogs to shift and retain the latter outwardly in full threaded engagement with box threads. Thus, the whipstock is secured to the bridge plug or packer in a desired position, with the concave surface 21 of the whipstock oriented in the same direction as the orienting pins 14 of the well packer.A suitable upward pull taken on the tubing string will disrupt the setting stud 121 and permit the tubing string 1 8 and setting tool 120 to be removed from the well bore.

Once the whipstock is set and anchored in place, a milling operation can be initiated, in a known manner, through use of a suitable mill 1 50 attached to a drill string 151, the mill being deflected laterally by the concave surface 21 of the whipstock and in the predetermined direction, to cut a window W through the casing as a result of rotation of the drill string (Fig. 5).

The apparatus and method described above is also useful in connection with setting a whipstock after a casing mill has been used to cut away a desired length of casing in a known manner. The bridge plug or anchor is set in the casing below the removed casing section, and the hole sidetracked through use of a suitable tool which is deflected in the desired direction by the whipstock.

Claims (14)

Claims

1. Apparatus for securing a whipstock in a well bore comprising an anchor, means for securing said anchor in the well bore, a whipstock, anchor means secured to said whipstock and having coupling means thereon, said coupling means being engageable with said anchor to secure said anchor means to said anchor and prevent movement of said whipstock in the well bore.

2. Apparatus according to claim 1, in which said anchor securing means includes normally retracted slips on said anchor and a setting tool removably secured to said anchor for expanding said slips into anchoring engagement with the well bore.

3. Apparatus according to claim 1 or claim 2, in which said anchor includes an upper threaded member with said coupling means including a threaded latch movable downwardly along said upper thread member and into latching engagement with said upper threaded member.

4. Apparatus according to any preceding claim, in which said anchor includes a first directional device, there being means for determining the direction in which said first device is pointing, means for turning said anchor to point said first device in a predetermined direction, and said anchor securing means enabling said anchor to be secured with said first device pointing in said predetermined direction, said anchor means including a mandrel having a second directional device aligned with including a mandrel having a second directional device aligned with said whipstock, said second device being engageable with said first device to turn said mandrel, anchor means and whipstock to face said whipstock in said predetermined direction, engagement of said coupling means with said anchor allowing said whipstock to remain facing in said predetermined direction.

5. Apparatus according to claim 4, in which said anchor has a passage in which said first device is located and said mandrel is movable downwardly in said passage to align said second device with said first device.

6. Apparatus according to claim 4, in which one of said first and second devices includes a pin with the other of said first and second devices including a longitudinal groove for receiving said pin.

7. Apparatus according to claim 5 and claim 6, in which said first device includes said pin with said second device including said longitudinal groove for receiving said pin to retain said whipstock facing in said predetermined direction.

8. Apparatus according to claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.

9. A method for securing a whipstock in a well bore comprising lowering an anchor into the well bore, securing said anchor in the well bore, then lowering into the well bore a whipstock secured to anchor means, and finally causing said anchor to be engaged by coupling means on said anchor means, to secure said anchor means to said anchor and prevent movement of said whipstock in the well bore.

10. A method according to claim 9, including lowering the anchor and a first directional device thereon into the well bore to a desired setting depth the turning the anchor until the first device points in a desired direction, setting the anchor in the well bore with the first device still pointed in said desired direction, then lowering into the well bore the whipstock secured to the anchor means which is itself secured to a mandrel having a second directional device aligned with the whipstock, engaging said second device with said first device to turn the mandrel, anchor means and whipstock to face the whipstock in said desired direction, and finally coupling the anchor means to the anchor to secure the whipstock to the anchor and retain the whipstock facing in said desired direction.

11. A method according to claim 10, in which before turning the anchor a survey is taken of the direction in which the first device is oriented, to determine the extent to which the anchor is to be turned to point the first device in the desired direction, after which the anchor is turned to the required extent and then set in the well bore.

12. A method according to claim 10 or claim 11, in which the anchor is set by a setting assembly releasably secured to the anchor and withdrawable from the well bore before the whipstock, anchor means and mandrel are lowered into the well bore.

13. A method according to claim 12, in which an orienting sub is disposed above the setting assembly and is aligned rotationally with the first device, a survey being taken with a survey instrument disposed in said orienting sub to determine the direction in which the first device is oriented to determine the extent to which the anchor is to be turned to point the first device in the desired direction, after which the anchor is turned to the required extent and then set in the well bore.

14. A method according to claim 9 and substantially as hereinbefore described with reference to the accompanying drawings.