Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and a whipstock having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and a whipstock having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: The invention provides an apparatus for actuating a downhole tool by utilizing a pressure differential created by fluid flowing through a conduit. The conduit is in communication with a pressure sensing line that is selectively exposable to areas of the conduit having different pressures. By exposing the pressure sensing line to a portion of the conduit having a predetermined pressure therein, the pressure sensing line causes actuation of a hydraulic tool therebelow.

Abstract: The side tracking system includes a window mill having a full diameter cutting surface and a reduced diameter tapered cutting surface and a whipstock having a ramp engaging the reduced diameter cutting surface. The materials of the whipstock have a first cutablity and the materials of the casing have a second cutability. The reduced diameter cutting surface contacts the whipstock ramp at a first contact area and the full diameter cutting surface contacts the wall of the casing at a second contact area. As weight is applied to the mill, there is a first contact stress at the first contact area and a second contact stress at the second contact area. A cutability ratio is the first cutability divided by the second cutability and a contact stress ratio is the first contact stress divided by the second contact stress. The mill cuts the casing rather than the whipstock by maintaining the product of the cutability ratio and the contact stress ratio less than one.

Abstract: Apparatus for boring a hole from an inside of a tube outwardly perpendicular to a longitudinal axis of the tube comprises a drill shoe having a longitudinal axis and being positionable in the tube, the shoe having an inlet, an outlet perpendicular to the shoe longitudinal axis and a passageway connecting the inlet and outlet, a torsional load transmitting element having no torsional flexibility in relation to its bending flexibility, having a longitudinal axis and being disposed in the passageway, the torsional load transmitting element being movable relative to itself with no resistance about first and second perpendicular axes both of which are perpendicular to the longitudinal axis of the torsional load transmitting element, a hole saw connected to one end of the torsional load transmitting element and a motor rotatably connected to the other end of the torsional load transmitting element.

Abstract: The present invention provides an improved coring motor for use in obtaining a core sample from the side wall of a drilled bore hole. The present invention provides controllable rotation, extension and retraction of the coring bit relative to the side wall without complicated positioning linkages and with conservation of space for use in slim tools for use downhole.

Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and a whipstock having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: Apparatus for boring a hole from an inside of a casing outwardly at an angle relative to a longitudinal axis of the casing comprises a drill shoe having a longitudinal axis and being positionable in the casing, the shoe having first and second passageways which converge into a third passageway exiting the shoe, a torsional load transmitting element and a cutting element connecting to one end of the torsional load transmitting element, the torsional load transmitting element and cutting element being positioned in the first passageway during non-use and in the third passageway during use, and a fluid conduit and a nozzle connected to one end of the fluid conduit, the fluid conduit and nozzle being positioned in the second passageway during non-use and in the third passageway during use.

Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and a whipstock having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: A borehole tool, such as a seismic shuttle-type logging tool, including a tool body having at least one sensor package and an anchoring mechanism, the anchoring mechanism having a drive mechanism including a motor, a drive shaft and a clutch; an anchoring arm moveable between first (extended)and second (retracted) positions relative to the tool body; a push rod connecting the anchoring arm to the drive mechanism; and a spring acting to bias the arm into a first position relative to the tool body. The push rod extends through the clutch mechanism and is engaged by the spring to bias the arm into the first position, and is also driven by the drive mechanism through the clutch to move the arm between the first and second positions. The spring is a coil spring surrounding the drive mechanism and acting on the push rod directly.

Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and a whipstock having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: An apparatus and method for utilizing a flexible tubing string (18) for forming and isolating a lateral entrance opening (23) to a lateral bore hole (25) from a main bore hole (10). A packer (38) mounted on the lower end of a tubular guide (40) has an elbow (56) between an upper central entrance opening (58) and a side exit opening (60). The packer (38) and tubular guide (40) are lowered within the main bore hole (10) to a predetermined depth and azimuth for side exit opening (60) which is positioned adjacent the proposed lateral bore hole (25). Packer (38) is then inflated. The flexible tubing string (18) having a hole forming member on its lower end is lowered within tubular guide (40) and elbow (56) for forming the lateral entrance opening (23, 24) for the lateral bore hole (25) with opening (23, 24) isolated.

Abstract: Apparatus for drilling lateral drainholes from a well casing comprises a flexible shaft having a bit at the lower end; the shaft extending through a shaft guide conduit anchored within the casing adjacent an oil-bearing formation. The “L” shaped guide conduit re-directs the shaft from an path parallel to the casing, through an elbow, to a path substantially perpendicular to the casing. The flexible shaft is formed of a helically wound outer coil spring and one or more helically wound and smaller inner coil springs residing concentrically therein. Each coil spring is closely fitted within the other. Each coil spring is wound opposite in direction to that of the next adjacent coil spring so as to interfere when under torsion. Bushings are located within the elbow for causing the shaft to flex and turn while permitting rotation and axial movement therethrough. A motor imparts torque into the top of the shaft, preferably through an intermediate driveshaft.

Abstract: A directional or horizontal hole may be drilled into a formation by first positioning or orienting a window turning shoe in an original well bore. Once the window turning shoe has been positioned, a window is milled through the casing with a window mill. The window mill is then removed and a guide tool is then latched to the window turning shoe. Once in position, the guide tool enables a mechanical motor driven curve drilling assembly to create a curved hole. Following the completion of the curved hole, the directional or horizontal hole is extended with a conventional drilling assembly.

Abstract: Multiple wellbores are interconnected utilizing a deflection device having a guide layer of lower hardness than the body of the deflection device, and a cutting tool having a guide portion and being operative to cut through the deflection device guide layer and a tubular structure lining a wellbore.

Abstract: Down hole assembly and method for forming a longitudinal window and a key-way in communication with the longitudinal window used in drilling multi-lateral well bores and for entry and reentry thereafter comprising, a first milling drill bit for milling the longitudinal window, a first whip stock having a guide surface, and orientation and positioning members located on the first whip stock for orienting and positioning tools to be used in forming the key-way in communication with the longitudinal window. A guide surface member is provided on the first whip stock member for guiding the first milling drill bit for milling a longitudinal window. A housing member for slidable mating with the first whip stock having a second drill bit member mounted in the housing member is provided for forming a down hole orientation key-way in communication with the longitudinally milled window.

Abstract: A deflection apparatus is provided. In one described embodiment, the apparatus includes a torque resistant retrievable whipstock sealingly attached to a packer. The whipstock may be separated from the packer by applying an axial force to a first housing and thereby releasing a sleeve sealingly disposed between the first housing and a second housing for displacement relative to the second housing. The first housing and sleeve may then be removed from within the second housing, leaving a relatively large diameter seal bore attached above the packer.

Abstract: Apparatus and methods are provided for achieving a lateral wellbore connection in a subterranean well. In one described embodiment, a deflection device is rotatably attached to one orienting member and conveyed into a cementing shoe positioned in a parent wellbore of the well, wherein the orienting member is engaged with another, complementarily shaped, orienting member. The deflection device is then rotated to face toward the lateral wellbore-to-be-drilled and a force is applied to the deflection device, thereby fixing its rotational orientation relative to the orienting members. Cutting tools are deflected off of the deflection device to cut outward through the cementing shoe to form the lateral wellbore.

Abstract: The present invention, in certain embodiments, includes a whipstock system with a body having an upper concave and a lower end, anchor apparatus on the lower end of the body, the anchor apparatus having a movable member releasably connected to the lower end of the body, and movable radially with respect to the lower body, the lower end of the body and movable member initially occupying a first space with a first diameter, and the movable member and lower end of the body movable apart from each other to anchor the whipstock system in a wellbore tubular. In one aspect there is one or more toothed slips on the movable member for engaging an interior surface of the wellbore tubular in which the whipstock system is to be anchored. In one aspect such a system can be used "through tubing".

Abstract: A method of interconnecting wellbores is provided which is convenient and economical in its performance. In a described embodiment, milling is not required for forming an opening through a sidewall of casing positioned in a parent wellbore. Instead, an appendage is formed from the casing sidewall and deformed outwardly into a void. A lateral wellbore may then be drilled through the casing sidewall. A liner may be positioned in the lateral wellbore and attached to the appendage.

Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and an upper section having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: A method of completing a subterranean well and associated apparatus therefor provide efficient operation and convenience in completions where production of fluids from a lateral wellbore and a parent wellbore is desired. In one disclosed embodiment, the invention provides an efficient method of protecting a junction of multiple wellbore portions by positioning a tubular drilling guide within the well extending through the junction. In one aspect of the present invention, the drilling guide is sealingly engaged with certain ones of the wellbore portions while drilling operations are being performed.

Abstract: Multiple drain drilling and production apparatus (16) comprising a generally cylindrical body (18) adapted to be located within a well, and an orienting assembly (24, 28) adapted to be received in the body (18) to deviate a drill string received within the body, at a predetermined depth, from a path coaxial with the body to a path at a predetermined angle to the axis of the body. The apparatus comprises at least one outlet (20) comprising a generally tubular element (42) received within the body and opening thereinto and displaceable from a first position generally coaxial with the body, into a second position at a predetermined angle thereto, by an actuator (200) received within the body, the orienting assembly being located adjacent the outlet (20).

Abstract: A thru-tubing retrievable whipstock is disclosed. A running tool creates relative movement to pivot out anchors at the lower end of the whipstock to accomplish its support. The setting force is trapped by spring-loaded wedges. The whipstock can be released and retrieved through tubing by undermining the wedges which allows retrieval of the whipstock by a pick-up force on the whipstock which collapses the anchoring mechanism for retrieval of the entire assembly to the surface.

Abstract: The side tracking system includes a window mill having a full diameter cutting surface and a reduced diameter tapered cutting surface and a whipstock having a ramp engaging the reduced diameter cutting surface. The materials of the whipstock have a first cutablity and the materials of the casing have a second cutability. The reduced diameter cutting surface contacts the whipstock ramp at a first contact area and the fill diameter cutting surface contacts the wall of the casing at a second contact area. As weight is applied to the mill, there is a first contact stress at the first contact area and a second contact stress at the second contact area. A cutability ratio is the first cutability divided by the second cutability and a contact stress ratio is the first contact stress divided by the second contact stress. The mill cuts the casing rather than the whipstock by maintaining the product of the cutability ratio and the contact stress ratio less than one.

Abstract: A tool for wellbore sidetracking operations has been invented, the tool, in one aspect, having a body, a milling section on the body for milling an opening in a tubular in a first wellbore in a formation, the milling section having milling material thereon, and a drilling section on the body for drilling a second wellbore beyond the window into the formation.

Abstract: The whipstock assembly comprises an assembly casing (9) with preformed windows connected to production casing (7); a landing tube (21) is located within assembly casing (9) for receiving whipstock shaft; a key is located within tube (21) for cooperation with J-slot on whipstock shaft. The whipstock consists of upper (49) and lower (55) portion which are fixed against relative rotation by splines. The assembly casing (9) with landing tube (21) is positioned in the borehole using a gyro survey tool for correct orientation of the windows. After a first side hole has been drilled, upper portion (49) is raised and rotated to place wedge surface (51) for drilling a second side hole. Tube (21) is initially closed by a cap containing a marking fluid; after the cap has been drilled out the marking fluid indicates the removal of the cap. In a second embodiment two vertically spaced side holes are drilled.

Abstract: A mechanical set anchor wherein a plunger extending from a base end of an anchor body activates a pin type trigger which releases a spring utilized to set multiple slips extending from the body of the anchor. Continued downward compressive forces fully sets the slips into the borehole pipe casing. The slips are maintained in their fully set position by a locking nut. The slips are further set into the pipe casing after slips are released from the anchor body. The anchor is mechanically released by an upward pull under tension of sufficient strength to shear release pins that release the compressed spring fully retracting the slips within the anchor body so that the anchor may be tripped from the borehole without interference from the previously engaged slips.

Abstract: A method for recompleting a wellbore containing a casing and a tubing string extending from a surface through the casing to a zone of interest by through-tubing rotary drilling by forming an opening through the casing at a selected point, passing a rotatable drill string including a drill bit through the tubing and drilling a second wellbore by drilling out of the cased wellbore through the opening.

Abstract: 058457102 A method of completing a subterranean well and associated apparatus therefor provide efficient operation and convenience in completions where production of fluids from a lateral wellbore and a parent wellbore is desired. In one disclosed embodiment, the invention provides an efficient method of protecting a junction of multiple wellbore portions by positioning a tubular drilling guide within the well extending through the junction. In one aspect of the present invention, the drilling guide is sealingly engaged with certain ones of the wellbore portions while drilling operations are being performed.

Abstract: A mechanical set anchor wherein a plunger extending from a base end of an anchor body activates a pin type trigger which releases a spring utilized to set multiple slips extending from the body of the anchor. Continued downward compressive forces fully sets the slips into the borehole pipe casing. The slips are maintained in their fully set position by a locking nut. The anchor is mechanically released by an upward pull under tension of sufficient strength to shear release pins that release the compressed spring fully retracting the slips within the anchor body so that the anchor may be tripped from the borehole without interference from the previously engaged slips.

Abstract: A whipstock for guiding a cutting tool within a cased borehole. The whipstock having a guide surface for guiding engagement with the cutting tool. The guide surface having a first taper with the axis of the whipstock and a greater taper with the axis of the whipstock at the point that the center of the cutting tool reaches the inside diameter of the wall of the casing thereby more quickly moving the center point of the cutting tool across the wall of the casing.

Abstract: A one-trip assembly that includes the mill or mills for milling a window, the whipstock, the whipstock anchor or packer, and a valving assembly is disclosed which permits running in all the equipment needed for setting and orienting a whipstock and squeezing cement below the whipstock in one trip. Valving is provided which allows for the squeezing to go on after the whipstock packer is set. A feedback technique to determine that the milling assembly been pulled away from the cementing tube is incorporated into the assembly. In one embodiment, upon initiation of milling, pressure differential is used to shift a tube for valve actuation, effectively isolating the squeezed formation from pressures above the whipstock. In another embodiment, the whipstock is shifted to actuate an upper flapper. A second flapper valve is provided, preferably below the whipstock packer, which, responsive to pressure from below, is urged into a closed position.

Abstract: The invention relates to a slip design with substantially longitudinally oriented wickers, which can be used alone or in combination with transversely oriented wickers, to secure a downhole tool, such as a bridge plug or packer, against rotational forces, such as those imparted from a whipstock, as well as longitudinal forces, such as those ultimately delivered by pressure fluctuations from uphole or downhole. The longitudinally oriented wickers are further cammed against the casing since any imparted torque on the packer body contacts a corner or edge of the slip, imparting to it a camming action making it dig further into the casing surface.

Abstract: A whipstock has been invented that has a whipstock body, a concave connected to or formed integrally of the whipstock body, and connection apparatus for releasably connecting the whipstock body to another member. In one aspect the another member is anchor apparatus and the connection apparatus has a shearable member shearable to release the whipstock from the anchor apparatus that initially anchors the whipstock in a wellbore (or in a tubular member).

Abstract: The mill assembly and whipstock assembly include a mill having a tapered end which engages a ramp of the whipstock assembly. The ramp includes a plurality of surfaces having different angles whereby the rate of deflection of the mill by the whipstock varies as the mill is lowered into the borehole. In particular, the ramp of the whipstock includes two surfaces having steep angles, one steep angled surface causing the mill to punch through the wall of the casing and the second steep angle surface moving the center of the mill across the wall of the casing.

Abstract: A method for milling an opening in a tubular in a wellbore, the method comprising installing a mill guide in the tubular at a desired milling location, inserting milling apparatus through the tubular and through the mill guide so that the milling apparatus contacts the tubular at the desired milling location and contacts and is directed toward the tubular by the mill guide, and milling an opening in the tubular. In one aspect the method includes installing a whipstock in the tubular and disposing the mill guide adjacent the whipstock to protect a concave portion of the whipstock. In one aspect the method includes retrieving the mill guide from the wellbore and in another aspect includes retrieving the whipstock form the wellbore.

Abstract: An apparatus and method are disclosed for applying thrust (weight on bit) to a drill bit when drilling with a flexible drilling shaft while creating perforations in a cased well. The thrust is applied directly to the drill bit instead of applying it to the drill bit through the flexible drilling shaft. A support bracket is also in contact with a piston and is in slidable contact with the tool housing. A portion of the piston is positioned inside a chamber in the housing and is slidably attached to the chamber walls. As hydraulic fluid flows into the chamber opposite the piston, the piston is forced toward the drill bit. As the piston moves toward the drill bit, force is exerted on the support bracket which causes the bracket to move toward the drill bit. This force is transferred to the drill bit during the drilling process, thereby supplying the force (weight on bit) needed by the drill bit to effectively drill through a desired material.

Abstract: A mill kick out apparatus comprises a whipstock and a starter mill. The whipstock has a lower end pivotally connected to a supporting assembly, an upper end, an outer side for disposition adjacent one side of a well wall, and an inner side diametrically opposite the outer side. The outer side has a vertically elongate upper portion angularly disposed with respect to a lower portion thereof, whereby the upper portion may abut the one side of the well wall when the lower portion is inclined downwardly and inwardly with respect thereto. The inner side is configured to be disposed at a first downward and inward angle with respect to the one side of the well wall when the one side so abuts the upper portion of the outer side of the whipstock. A lug projects generally radially inwardly from the inner side of the whipstock adjacent the upper end and has a generally radially inwardly facing surface disposed at a second downward and inward angle with respect to the one side of the well wall.

Abstract: A wellbore sidetracking method has been invented which includes, in certain embodiments, milling out a casing section from a cased, cemented wellbore; placing a deflection device, e.g. a whipstock, so that, upon pivoting of the upper concave portion of the whipstock at least a top portion thereof extends up into and abuts casing above the milled out section and, in certain aspects, a portion of the whipstock also extends down into and abuts casing below the milled out section; introducing a mill into the wellbore to mill out a part of the casing above the milled out section which would interfere with the introduction of a drill bit; removing the mill; introducing a drilling system into the wellbore to be deflected into the milled out area; and drilling a new sidetracked bore with the drilling system from the milled out area. In one aspect a mill is provided which mills out the part of the casing above the milled out area without contacting the formation or with only minimal contact thereof.

Abstract: A mill kick out apparatus comprises a whipstock and a starter mill. The whipstock has a lower end pivotally connected to a supporting assembly, an upper end, an outer side for disposition adjacent one side of a well wall, and an inner side diametrically opposite the outer side. The outer side has a vertically elongate upper portion angularly disposed with respect to a lower portion thereof, whereby the upper portion may abut the one side of the well wall when the lower portion is inclined downwardly and inwardly with respect thereto. The inner side is configured to be disposed at a first downward and inward angle with respect to the one side of the well wall when the one side so abuts the upper portion of the outer side of the whipstock. A lug projects generally radially inwardly from the inner side of the whipstock adjacent the upper end and has a generally radially inwardly facing surface disposed at a second downward and inward angle with respect to the one side of the well wall.

Abstract: This invention relates to a permanent whipstock assembly which uses camming pivot arms to secure the whipstock at the desired location within a cased wellbore. Camming pivot arms are pivotally attached to the downhole end of a whipstock housing and are further attached to a slip pad. Intentionally induced relative movement of the slip pad and the whipstock housing causes the camming pivot arms to pivot in such a manner that slip pad housing 4 and slip pad 5 are forced away from each other and cammed into the cased borehole. The invention relates specifically to a device that is particularly adapted to be lowered through a small diameter and later to be activated and set in a much larger casing or hole diameter.

Abstract: A method and system for lateral drilling with respect to a main well which is cased by a casing string. At least a part of the casing string provides a lateral opening adapted to enable drilling of a lateral well. A guiding device is positioned at a part of the casing string in front of the lateral opening and the guiding device is controlled from the surface of the main well. A lateral casing string equips the lateral well and provided a sub for connecting the lateral casing string to the main string in the main well.

Abstract: The present invention, in one embodiment, discloses a whipstock system having an orientation device; a flexion member releasably secured to the orientation device; co-acting lower and upper body members, the lower body member interconnected with the flexion member; a connecting bar which connects the upper and lower body members permitting the upper body member to move downwardly with respect to the lower body member while preventing separation of the two body members; and a concave member secured to and above the upper body member. In one preferred embodiment, one or more movable pawls on the connecting bar move to engage surfaces on one or both body members to prevent upward movement of the upper body member with respect to the lower body member, or conversely movement of the lower body member downwardly away from the upper body member; and movement of the one or more pawls in contact with both body members also forces the two body members apart further stabilizing the system in a tubular.

Abstract: A method and system for translating the orientation of a length of coil tubing from a generally vertical orientation to a generally horizontal orientation, inside a well borehole and downhole of a wellhead. A first conduit is installed and suspended in a well borehole. The conduit is provided with a coil tubing bender at the downhole end of the conduit. Coil tubing is injected into the conduit through an upper packer attached to the top section of the conduit. After a section of coil tubing is injected into the conduit, an outer coil tubing seal is securely affixed to the coil tubing. The coil tubing is run to the top of the bender; the packer is closed; and high pressure fluid is introduced between the upper packer and the outer seal inside the conduit. The fluid forces the coil tubing through the bender and translates the coil tubing from a vertical to horizontal orientation.

Abstract: A millout whipstock has a cylindrical body with a stabbing nose at the bottom and a deflection shoe at the top. A drill string extending through the deflection shoe is connected to a pressure housing keyed in a torque key housing in the body. A piston, mounted in a piston housing secured in the body beneath the pressure housing, has an upper portion extending through the pressure housing and is pinned in a raised position by shear pins. A slip expander at the bottom of the piston engages slips supported adjacent openings in the side wall of the body. A fluid path extending through the drill string, pressure housing, piston housing, and piston, is closed off by a rupture disk. The body is lowered by the drill string onto a cement plug in the casing. The slips are set by applying fluid pressure in the drill string to shear the shear pins and force the piston and expander downward wedging the slips outward to grip the casing.

Abstract: A starter mill adapted for use with a whipstock to mill a window through the casing of a well for deviating the direction of drilling. The starter mill includes a bearing nose which is utilized to indicate completion of the milling process. As the mill nears completion of the milling process, the bearing nose will become wedged between the whipstock face and the casing preventing further downhole movement. The bearing nose will engage whipstock and casing, allowing the work string to continue to rotate although the decreased torque resulting from the absence of milling provides a clear signal that the milling operation is complete. The cutters of the mill are spaced a predetermined distance from the bearing nose to ensure completion of the casing window.

Abstract: A retrievable whipstock which can be hydraulically set within a wellbore and following the drilling procedure mechanically released and retrieved for future use. The whipstock includes a whip which directs a milling tool from the main well and a hydraulically actuated packer or anchor for setting the whipstock in the wellbore. The retrieval tool includes a nose piece to ensure proper orientation relative to the whipstock and a die collar to threadably engage the whip. An adapter on the retrieval tool wedges the whip away from the casing wall to ensure mating engagement between the retrieval tool and the whip. The whipstock is released through the application of tension through the retrieval tool allowing removal from the wellbore.

Abstract: A retrievable whipstock/anchor assembly is used to allow drilling of additional wellbores from an original or primary wellbore (which may be a highly deviated or horizontal open wellbore). The retrievable whipstock assembly is comprised primarily of two sections, an anchor section and a whip stock section. The anchor section provides resistance to compression and rotation forces, and provides rigidity for the whipstock. The whipstock provides a support face for drilling the additional wellbores. The whipstock can be oriented radially to allow drilling at any radial angle, and can be set at any depth. Anchoring of the retrievable whipstock assembly is provided by means of an inflatable element which expands to grip the inside wall of the wellbore. Radial orientation can be provided by rotating the retrievable whipstock assembly from surface or other means until the whipstock is at the desired orientation.

Abstract: A method for setting a whipstock in a wellbore on a packer-anchor which employs a wireline that carries a setting assembly which severs a shear member carried by the setting assembly after the whipstock is set onto the packer-anchor.