Title: Hydraulic Whipstock Anchor

Inventors: Gregory L. Hern; William A. Hered and Jason L. Cullum FIELD OF THE INVENTION

[0001] The field of the invention is hydraulic anchor assemblies for whipstocks in borehole use and more particularly anchors that release in a variety of ways, or cock the whipstock or that can be modularly built to optionally add setting capability with setting down weight or be reconfigured to add a hydraulically actuated sealing functionality to the anchor.

BACKGROUND OF THE INVENTION

[0002] Whipstocks are long tapered ramps that are secured in a tubular string to guide a mill assembly laterally to make an exit through the tubular wall for the start of a lateral bore. The taper angle is gradual, in the order of about 1-3 degrees. The ramp is typically oriented with a bottom hole assembly so that the ramp faces the direction of the desired lateral. In some instances there can be a need to have the lateral exit in a downward direction off a horizontal bore. In such cases it is advantageous to ensure that the top of the whipstock is pushed against the top of the horizontal run so that after the window in the casing has been milled a drilling assembly that will be deployed on a subsequent run will pass freely through the window in the casing without engaging the top of the whipstock.

[0003] Anchors that hydraulically extend from one side of a whipstock lower end to skew the whipstock are described in US 6843314. A design that uses a nonparallel slip face to the surrounding tubular for skewing the whipstock is described in US 8505651. Another way a whipstock is mounted off center in a surrounding tubular is to use an eccentrically mounted sealing element that is set with set down weight after an anchor is set mechanically or hydraulically is shown in US 2015/0345241. A non-releasing anchor that sets hydraulically and has the set position locked with a body lock ring is shown in US 5154231. A mechanically actuated whipstock anchor using relative movement of opposed inclined surfaces is shown in US 6360821.

[0004] What is needed and provided by the illustrated embodiments of the present invention is a hydraulic whipstock anchor that holds the set and can be released in a variety of ways. One way is to vent trapped hydraulic pressure that holds the slips out and one way that is done is to pull tension and fail a component that lets the hydraulic pressure relieve so that the slips can retract. Another way to slip release is to remotely close a circuit that allows electrical current to heat and break a wire to release a piston whose movement opens a vent port. Alternatively release of the piston can allow fluids to pass through a port that undermine a mechanical lock ring that holds the slips extended. The slips can be wedged out radially with axial movement of a cone or by radial piston movement with the slips on the piston ends. The anchor design can be modular so that removal of an end cap allows alternative slip setting by setting down weight or the ability to add a packer component to the housing end that is actuated hydraulically with the slips. Cocking of the whipstock top end to an upper part of a horizontal run for a downward casing exit can be accomplished with ramps sloped at different angles that induce a turning moment on the slips to rotate the whipstock body. Preferably the slips will be offset along the axis of the whipstock to further increase the turning moment to rotate the whipstock body. Alternatively, the slip assembly can be mounted on an axis that skews with respect to the whipstock body to impart a turning moment to the whipstock body for desired positioning of the top end of the whipstock. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiments and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.

SUMMARY OF THE INVENTION

[0005] A whipstock anchor is hydraulically set and locked in the set position. Release occurs with a pull induced component failure that relieves hydraulic pressure that allows the slips to retract. Release can occur with a remotely actuated circuit that burns a retainer for a piston whose movement opens a vent or initiates a chemical reaction to undermine a lock ring. Movement of a single cone or opposed cones extends the slips. The cone angles being different adds a skew to the slips and positions the top of the whipstock against the tubular top in a horizontal run. A bottom cap is removable to convert to setting by set down weight or to attach a hydraulically operated packer below the slips. Slips can be extended with radial movement of pistons. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a section view of a locking anchor design with a tensile release;

[0007] FIG. 1 a is the view along line 1 a- 1 a of FIG. 1

[0008] FIG. lb is an enlarged view of the slips in FIG. 1 showing the taper angle difference;

[0009] FIG. 2 is a section view of an alternative embodiment showing a skew in the anchor body with respect to the whipstock axis;

[0010] FIG. 2a is the view along line 2a-2a of FIG. 2

[0011] FIG. 3 is a section view of an embodiment showing opposed cone movement for slip extension;

[0012] FIG. 3 a is the view along line 3a-3a of FIG. 3;

[0013] FIG. 3b is an outside view of the slip retainer of FIG. 3;

[0014] FIG. 3c is a detailed section view of the slips in FIG. 3 showing differing opposed taper angles;

[0015] FIG. 4 is a section view of an embodiment that releases with a remote signal that allows a piston to move to release hydraulic pressure;

[0016] FIG. 4a is the view along line 4a-4a of FIG. 4;

[0017] FIG. 5 is a section view of an embodiment that moves a slip radially with a radially oriented piston and releases with a remote signal that vents hydraulic pressure;

[0018] FIG. 5a is an outside view of the slips showing a retainer for the moving slips;

[0019] FIG. 6 illustrates a modular hydraulically operated packer that can be mounted to the slip assembly;

[0020] FIG. 7 is a section view of an anchor that is releases with a remote signal that allows a piston to move to release an agent to undermine a body lock ring for anchor release;

[0021] FIG. 7a is a view along line 7a-7a of FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] Referring to FIG. 1, a whipstock 10 has a ramp 12 and an associated hydraulic line 14 that typically is run behind the ramp 12 to protect the line 14 from the advancing window mill that is not shown. A check valve 16 in line 14 allows flow one way into passage 18 to chamber 20 defined by cap 22 secured at thread 24 to housing 26. Cone 32 is sealed with seals 28 and 30 so that built up pressure in chamber 20 moves cone 32 in the direction of arrow 34 toward the housing 26. Two slips 36 are shown at 180 degree spacing although different spacing and number of slips is contemplated. The slips 36 have external carbide or hardened inserts 38 to dig into the surrounding tubular that is not shown to support the whipstock 10. A biasing spring 40 pushes between a respective slip 36 and a retainer 42 that limits the outward travel of each slip 36. A lock ring 44 is moved along ratchet profile 46 as cone 32 moves in the direction of arrow 34 to prevent reverse movement of the cone 32. The lock ring 44 in effect maintains the set of the slips 36 against the surrounding tubular that is not shown. Preferably ramp surfaces 48, 50, 140 and 142 have the same slope. Slip surface 144 has a slightly smaller slope than ramp surfaces 48, 50, 140 and 142, and slip surface 146 has a slightly greater slope than ramp surfaces 48, 50, 140 and 142 to put whipstock axis 152 into a cocked position with respect to horizontal axis 52 as schematically illustrates in FIG. lb. In a preferred embodiment the angle difference on opposed slip surfaces 144 and 146 is a degree but larger or even smaller differences are contemplated to skew the slip orientation in opposed directions as between slips with 180 degree spacing. The desired result is a skew is imparted to the whipstock 10 to keep its upper end (not shown) against the inside diameter (ID) of a horizontal pipe for making a downwardly oriented window exit. In essence the slips hardened inserts 38 are parallel to each other but both are skewed with the whipstock axis 152 to impart a rotational moment to whipstock 10 as indicated by arrows 54 and 56. Preferably ramps surfaces 48 and 50 will be closer to the top of the whipstock than ramps surfaces 140 and 142 to provide a fulcrum effect to create a greater force to keep the top of the whipstock pushed tighter against the ID of the horizontal pipe. Preferably the sloping surfaces 144 and 146 on the slips 36 are parallel to their respective opposing ramp surfaces 48, 140, 50, and 142 on cone 32 and housing 26 however, some angular difference is also contemplated as an option. Hardened inserts 38 are imbedded into slips 36 on either side of retainer 42. Width 148 on one side of slip 36 is greater than width 150 on the other side of slip 36. Having different widths on either side of slip 36 makes it possible to use identical slips at 180 degree spacing in housing 26 and have them installed in the proper orientation. Retainers 42 cannot be installed if slips 36 are installed in housing 26 incorrectly. Whipstock axis 152 will also be rotated if the slope of slip surfaces 144 and 146 are identical and housing ramp angle 48 is larger than ramp angle 140 and cone ramp angle 50 is smaller than ramp angle 142. Mandrel 58 has a necked down portion 60 so that when a tensile force is exerted on the whipstock 10 with slips 36 extended to the surrounding tubular the cone 32 and lock ring 44 retain the lower end of the mandrel 58 because the slips 36 bite into the surrounding tubular. The tensile force on mandrel 58 increases until a tensile failure occurs at necked down portion 60. As the mandrel 58 breaks at 60 the pressure in chamber 20 dissipates and the housing 26 has the ability to move up and away from the set slips 36 so they are no longer wedged against the surrounding tubular. The cone 32 is retained by cap 22 after the tensile failure at 60. It should be noted if the hydraulic system is filled with incompressible fluid the check valve 16 can hold the pressure against the set slips 36 using cone 32, however, the body lock ring 44 insures that the slips 36 cannot back away from the surrounding tubular after the set.

[0023] FIG. 2 is somewhat different than FIG. 1 in that a single radially moving slip 36 is used and is opposed by segment 62 with hardened or carbide inserts 64. Cone 32 is modified to have a taper only under the single slip 36 whose extension brings the inserts 64 to the surrounding tubular wall. In this version the hardened inserts 38 in slip 36 are parallel to hardened inserts 64 in segment 62, but are at a small angle with respect to whipstock axis 152of the whipstock 10 such that extension of slip 36 until inserts 64 reach the surrounding tubular 180 degrees away will wind up pushing the top end of the whipstock against the surrounding pipe to keep it out of the way of the advancing window mill. Housing 26 is conically shaped below arrows 66 to provide clearance when the bottom of the whipstock 10 is rotated toward the tubing wall. The skew in FIG. 2 can be further enhanced with the orienting of the one slip 36 akin to the manner previously described in the discussion of FIG. lb.

[0024] FIG. 3 is the same as FIG. 1 with the exception that there are opposed pistons that move on opposite sides of the slips 36. Mandrel 58 that was threaded to housing 26 in FIG. 1 is now slidably mounted after breaking shear pin 68. A lock ring 70 only allows mandrel 58 to move in the direction of arrow 72 with its final position locked in with lock ring 70. As before cone 32 moves in an opposite direction toward slips 36 and its set position is locked with lock ring 44. Pin 74 extends from housing 26 into slot 76 in mandrel 58 to prevent relative rotation between the two. As before release occurs with a tensile failure at decked down portion 60 in response to a tensile force on whipstock 10.

[0025] In FIG. 4 the arrangement of the gripping is the same as FIG. 2 in that there is a slip 36 located 180 degrees opposite a segment 62 with hardened or carbide inserts 64. As before pressure in line 14 goes through check valve 16 and against piston 80 that has a peripheral seal 82. Spring 84 pushes piston 80 away from slip 36 until the spring force is overcome with pressure in line 14. Piston 80 has a through bore 78 blocked by plug 86 that has a seal 88. A battery and signal receiver 90 gets a remote signal to close a circuit which then heats a wire 92 operatively connected to retainer 94 to defeat it which constitutes the trigger so that plug 86 can move and take seal 88 past vent passage 96 to relieve the pressure above piston 80 which in essence allows spring 84 to push piston 80 away from slip 36 to allow removal of the whipstock 10 without well intervention which means avoiding sticking tools in the borehole to accomplish the task. Again in this version the hardened inserts 38 in slip 36 are parallel to hardened inserts 64 in segment 62, but are at a small angle with respect to whipstock axis 152 of the whipstock 10 such that extension of slip 36 until inserts 64 reach the surrounding tubular 180 degrees away will wind up pushing the top end of the whipstock against the surrounding pipe to keep it out of the way of the advancing window mill. Surface 98 is stationary as the slip 36 is guided at end 100 by a rail or dovetail. In this design the line 14 pressure held by check valve 16 holds the set position of the slip 36.

[0026] The signal can be sent without well intervention in a variety of known ways such as acoustic, electromagnetic, mud pulse or vibration. A fixed lug retrieval tool that engages the whipstock for whipstock retrieval could mechanically close a circuit that would initiate opening of the trigger. The fixed lug retrieval tool could include a magnet that activates a sensor in the whipstock. Using the fixed lug retrieval tool to initiate pressure release could include running a wire from the whipstock to the battery. That is, a sensor is optional in the anchor. Closing the circuit to active the pressure release could be controlled from the whipstock instead of at the anchor.

[0027] FIG. 5 uses line 14 and check valve 16 to feed pressure to radially extend pistons 110 that each have hardened or carbide inserts 112. Located 180 degrees opposite are fixed inserts 114, that are parallel to hardened inserts 1 12, but at an angle with respect to whipstock axis 152. There are return springs 116 on each piston 110. The release system in FIG. 5 works the same way as in FIG. 4 in response to a remote signal to vent pressure and allow return springs 116 to retract the pistons 110. As with FIG. 4 the applied line 14 pressure trapped by the check valve 16 holds the set position. Any different amount of pistons 110 can be used and some can be articulated in a 180 degree opposed orientation. As before a retainer 42 limits the extension of the pistons when there is no surrounding tubular present.

[0028] FIG. 6 is intended to show that cap 22 of FIG. 1 can be removed at thread 24. When that happens cone 32 can be converted to set down weight operation against hole bottom. Alternatively, a packer module 120 can be attached at thread 24 to in essence recreate chamber 20 for operation of cone 32 as in FIG. 1 but to also extend a passage for hydraulic pressure to port 122 to drive piston 124 against seal assembly 126 and against fixed surface 128 so that slips 36 can be extended as well as a seal assembly 126. A lock ring 130 holds the set of the seal assembly 126. As before a tensile force on the whipstock 10 creates a tensile failure at necked down portion 60 to allow release of at least the slips 36.

[0029] FIG. 7 has a slightly different release system that acts to undermine the lock ring 44. The layout is similar to FIG. 4 with the difference being that actuation of plug 86 by system 90 based on a remote signal moves seal 88 past passage 96 to allow fluid in chamber 130 to reach lock ring 44 and undermine it with chemical attack or an equivalent way.

[0030] Those skilled in the art will appreciate that the various design alternatives presented show a whipstock anchor that can be hydraulically set and can hold the set position with a check valve on the hydraulic line. Alternatively a lock ring can hold the set position and release occurs when a tensile force results in tensile failure of a mandrel to release the hydraulic pressure. Alternatively a release of hydraulic pressure can be remotely actuated with release of a retained plug whose movement vents hydraulic pressure or disables or undermines a lock ring chemically. A single piston can extend a slip with movement against a fixed surface or two pistons can be pushed in opposed directions. Movable slips can be oriented in opposition to each other or a movable slip can be opposite a fixed slip with inserts. Cocking of the whipstock can be accomplished by skewing the housing for the slips with respect to a whipstock axis or skewing the slip axis relative to an aligned whipstock and anchor housing axis. The designs feature simplicity in a hydraulically set anchor for a packer with a resultant economy in manufacturing. A removable cap can be used for hydraulic operation of a piston and with the cap removed for operating the piston with set down weight. A seal module can be secured in place of the end cap to allow setting a packer with the anchor and to release the anchor and the seal assembly when necked down portion 60 is broken.

[0031] The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: