Abstract: A steering pad apparatus for a rotary steerable system is provided. The steering pad apparatus comprises a base comprising one or more base lugs, each of the base lugs defining a respective axial hole therein. The apparatus further comprises a steering pad hingedly coupled to the base, the steering pad comprising one or more pad lugs, each said pad lug defining a respective axial hole therein. The one or more pad lugs are coupled to the one or more base lugs such that each of the one or more pad lugs is adjacent to at least one of the one or more base lugs. The apparatus further comprises, for each adjacent base lug and pad lug, a respective one or more bushings received in at least one of: the hole of the pad lug; and the hole of the base lug.

Abstract: A system can be used for drilling a wellbore. The system can include a steering collar, an actuation cylinder, and a radial seal. The steering collar can be positioned on a drilling tool for forming a wellbore. The actuation cylinder can be positioned on the drilling tool for abutting a steering pad for actuating the steering pad. The radial seal can be positioned on the drilling tool between the steering collar and the actuation cylinder.

Abstract: Provided is a kit for treating tissue of a subject. The kit includes a tool for creating a wedge opening within a bone tissue, and an implant. In some examples, the kit also includes an introducer configured to deliver the implant into the wedge opening.

Abstract: A rotary steerable tool for steering a drill string may include a tool collar extending along a longitudinal axis of the tool, a pad pusher, a pad retention housing, and a piston liner. The pad pusher may be rotatable about a pivot axis thereof between retracted and extended positions relative to the tool collar, for steering the drill string. The piston liner may be coupled to the pad retention housing and have a piston channel that defines a curved profile. The piston liner may provide sealing contact against a perimeter of the piston upon pivoting of the pad pusher through the piston channel along the curved profile, relative to the piston liner.

Abstract: A cutting assembly and method for drilling an underground borehole. The cutting assembly includes front and rear cutting heads of different diameters mounted on a shaft. An air passage defined through the cutting assembly may be placed in fluid communication with a pressurized remote air source and with a bore of a casing extending rearwardly from the cutting assembly. Pressurized air flows through the air passage and entrains cuttings produced by the front and rear cutting heads. A housing extends rearwardly from the larger diameter rear cutting head and an auger provided within the housing aids in directing cuttings into the casing. The auger rotates independently of the rest of the cutting assembly and may be configured to further reduce the size of the cuttings. A collar on the housing seals the borehole cut by the rear cutting assembly and aids in preventing frac-out.

Abstract: Downhole drill pipe cutting is achieved by a free-falling sub carrying a shaped charge cutter and an ablative fluid cutter. Upon seating on a drill string flow bore orifice, fluid pressure is raised to detonate the shaped charge cutter. In the event the shaped charge cutter fails, pressure is further raised to effect a cut by fluid ablation.

Abstract: An apparatus and method for drilling an underground borehole where pressurized air may be used to discharge cuttings produced by a cutting assembly. The cutting assembly includes a shaft having a first and second ends and a bore extending between the ends. First and second cutting heads are provided on the shaft a distance apart. The second cutting head is rearward of the first cutting head and is of a greater diameter. Each cutting head defines an air passage therethrough that is in fluid communication with the shaft's bore. A housing extends rearwardly from the second cutting head and connects to a length of casing. An annular flange, concentric with the housing, seals the borehole as the cutting assembly rotates and moves forward through the ground. Cuttings generated by the assembly are moved therethrough and discharged from the casing by pressurized air provided to the assembly through the shaft's bore.

Abstract: A drilling assembly for simultaneous hole enlargement operations comprises a drill bit, an adjustable diameter reamer, and a hole opener. The reamer is coupled with, and positioned uphole from the drill bit. The reamer is adjustable between a first diameter and a second diameter that is larger than the first diameter. The hole opener is coupled with, and positioned uphole from the reamer.

Abstract: The present invention concerns an apparatus for modifying sidewalls of a borehole. The apparatus includes a longitudinal housing adapted to fit inside the borehole. The housing includes a first end portion, a second end portion, and a side portion between said end portions, adapted to face the sidewalls of the borehole. Means are provides on the side of the housing for removing material from said borehole sidewall. The housing is adapted to be rotated with a controlled rotational speed in relation to said borehole sidewalls and to be fed in a controlled rate of longitudinal motion in relation to said borehole. Furthermore, the invention relates to a method for making a borehole with internal, helical grooves.

Abstract: An expandable reamer apparatus and methods for reaming a borehole, wherein a laterally movable blade carried by a tubular body may be selectively positioned at an inward position and an expanded position. The laterally movable blade, held inwardly by blade-biasing elements, may be forced outwardly by drilling fluid selectively allowed to communicate therewith by way of an actuation sleeve disposed within the tubular body. Alternatively, a separation element may transmit force or pressure from the drilling fluid to the movable blade. Further, a chamber in communication with the movable blade may be pressurized by way of a downhole turbine or pump. A ridged seal wiper, compensator, movable bearing pad, fixed bearing pad preceding the movable blade, or adjustable spacer element to alter expanded blade position may be included within the expandable reamer. In addition, a drilling fluid pressure response indicating an operational characteristic of the expandable reamer may be generated.

Abstract: This disclosure relates in general to a method and system for controlling a drilling system for drilling a borehole in an earth formation. More specifically, but not by way of limitation, embodiments of the present invention provide systems and methods for controlling dynamic interactions between the drilling system for drilling the borehole and an inner surface of the borehole being drilled to steer the drilling system to directionally drill the borehole. In another embodiment of the present invention, data regarding the functioning of the drilling system as it drills the borehole may be sensed and interactions between the drilling system for drilling the borehole and an inner surface of the borehole may be controlled in response to the sensed data to control the drilling system as the borehole is being drilled.

Abstract: Earth-boring tools may have a body, a cutting element attached to the body at a first location, and a formation-engaging structure attached to the body at a second location. The formation-engaging structure may be movable during a drilling operation between a first position and a second position. In the first position, the formation-engaging structure may be located rotationally behind the cutting element at a first radial distance from a longitudinal axis of the body at which the cutting element will at least initially shield the formation-engaging structure from engaging a formation. In the second position, the formation-engaging structure may be located at a different second radial distance from the longitudinal axis of the body at which the formation-engaging structure will engage a formation.

Abstract: An undercutting tool for producing transverse grooves in a drilled hole. An upper support and a lower support axially delimit a receiving region of a shank. At least two spreading elements are disposed in the receiving region between the spreading elements and the receiving region. The shank and the supports are disposed so the axial distance between the supports can be reduced by exerting an axial force. The spreading elements each have an oblique upper and lower end face, which each have such an outer geometric shape, extending in a direction not perpendicular to the longitudinal axis and are displaced in substantially opposite radial directions, and the axial force is in each case converted to a radial force in the radial directions.

Abstract: In one aspect of the present invention, a steering assembly for downhole directional drilling comprises an outer bit comprising a bore and an outer cutting area and in inner bit comprising an inner cutting area and connected to a shaft that is disposed within the bore. At least one biasing mechanism is disposed around the shaft. At least one fluid channel is disposed within the outer bit and redirects fluid to the at least one biasing mechanism causing the at least one biasing mechanism to push the shaft and alter an axis of the inner bit with respect to an axis of the outer bit.

Abstract: The present specification describes a drill bit for drilling a cavity. The drill bit may include a chassis, a plurality of gauge pad sets, and at least one gauge pad structure. The chassis may be configured to rotate about an axis. The plurality of gauge pad sets may each include at least one gauge pad. The at least one gauge pad structure may moveably couple at least one of the gauge pads of at least one of the plurality of gauge pad sets with the chassis.

Abstract: This disclosure relates in general to a method and system for controlling a drilling system for drilling a borehole in an earth formation. More specifically, but not by way of limitation, embodiments of the present invention provide systems and methods for controlling dynamic interactions between the drilling system for drilling the borehole and an inner surface of the borehole being drilled to steer the drilling system to directionally drill the borehole. In another embodiment of the present invention, data regarding the functioning of the drilling system as it drills the borehole may be sensed and interactions between the drilling system for drilling the borehole and an inner surface of the borehole may be controlled in response to the sensed data to control the drilling system as the borehole is being drilled.

Abstract: A drill bit direction system and method is disclosed that modifies or biases the stochastic movement of the drill bit to change a drilling direction of a drilling system. The direction of the drill bit is monitored to determine if the direction happens to align in some way with a preferred direction. If the direction isn't close enough to a preferred or desired direction, stochastic motion of the drill bit in the borehole may be controlled and/or motion of the drill bit under a side force acting on the drill bit to direct the drilling may be focused or biased to modify the direction of drilling closer to the preferred direction. Any of a number of stochastic motion control mechanisms or biasing mechanisms can be used. Some embodiments can resort to conventional steering mechanisms to supplement the stochastic motion control or side force biasing mechanisms.

Abstract: A reamer is designed to enhance operation of a bottom hole assembly in which it is included. One or more capabilities and/or characteristics of the cutters carried by the reamer blocks of the reamer may be varied even in the same profile portion to enhance the functionality and/or durability of the reamer.

Abstract: An electronically activated tool (50) comprising a tool body, cutter blocks and sensors with means for attachment to a drilling support and rotation so as to permit the simultaneous underreaming and measurement of the diameter of a wellbore (especially in oil and gas drilling) characterized by a means of activation using an electronic signal sent by mud-pulse, fiber-optics, wireless transmission or other means which may also communicate commands and receive data from the underreamer during drilling, at least one radially extendable cutter block (62) incorporating positional sensors adapted to measure the relative position of the cutter block to the tool, at least one calliper means (76) to measure wellbore diameter, all of which are inter-linked by a means of communication using receivers, sensors and microprocessors and a system that optimizes underreaming or expansion (22) by simultaneously comparing and correlating wellbore diameter data (22) and underreaming parameters in real-time or in memory.

Abstract: A well bore reamer has an elongated body for coupling between members of a well string, a first set of cutting elements on the body at a fixed position, a second set of cutting elements on a sleeve closing around a sleeve carrying portion of the elongated body. The sleeve is slidable along a longitudinal axis of the body and rotatable thereabout. A lower clutch mechanism operates between the sleeve and the elongated body at a bottom end of the body's sleeve carrying portion to block rotation of the sleeve relative to the elongated body in a predetermined direction about the longitudinal axis under sliding of the sleeve into a lowered position adjacent said bottom end of the sleeve carrying portion.

Abstract: A well bore reamer has an elongated body for coupling between members of a well string, a first set of cutting elements on the body at a fixed position, a second set of cutting elements on a sleeve closing around a sleeve carrying portion of the elongated body. The sleeve is slidable along a longitudinal axis of the body and rotatable thereabout. A lower clutch mechanism operates between the sleeve and the elongated body at a bottom end of the body's sleeve carrying portion to block rotation of the sleeve relative to the elongated body in a predetermined direction about the longitudinal axis under sliding of the sleeve into a lowered position adjacent said bottom end of the sleeve carrying portion.

Abstract: In one aspect of the invention, an expandable tool for an earth boring system comprises a through bore configured to accommodate drilling fluid. A blade is configured to extend and retract out of an outer surface of the tool. A secondary fluid pathway connects the bore with an interface between the outer surface of the tool and a surface of the blade. The secondary pathway directs drilling fluid through the interface.

Abstract: An expandable downhole tool apparatus is disclosed. The apparatus comprises a body adapted to be incorporated into a drill string and at least one working member moveable relative to the body between an inward deactivated position and an outwardly deployed activated position in order to engage the wall of a borehole. Activation means adapted to move at least one said working member between the inward deactivated position and outwardly deployed activated position is provided. At least one passage is formed through the body and extends from a location on the body adjacent at least one working member to a location remote from the respective working member to enable debris accumulating underneath the respective working member to move along the passage and exit the body.

Abstract: A method for forming and sealing a hole in a sidewall of a borehole may include conveying a bit and a sealer into the borehole using a carrier, forming a hole in the sidewall using the bit, and introducing a sealant from the sealer to the hole along a surface portion of the bit. An apparatus for forming and sealing a hole in a sidewall of a borehole includes a carrier conveyable into the borehole, a bit disposed on the carrier that forms the hole in a sidewall, and a sealer operable to introduce a sealant to the hole along a surface portion of the bit.

Abstract: A drill bit direction system and method is disclosed that modifies or biases the stochastic movement of the drill bit and/or stochastic interactions between the drill bit and an inner-wall of a borehole being drilled by a drilling system to change the direction of drilling of the drilling system. The direction of the drill bit is monitored to determine if the direction happens to align in some way with a preferred direction. If the direction isn't close enough to a preferred direction, a biasing mechanism modifies the stochastic movement in an attempt to modify the direction closer to the preferred direction. Any of a number of biasing mechanisms can be used. Some embodiments can resort to conventional steering mechanisms to supplement the biasing mechanism.

Abstract: A drilling system includes a steerable bottomhole assembly (BHA) having a steering unit and a control unit that provide dynamic control of drill bit orientation or tilt. Exemplary steering units can adjust bit orientation at a rate that approaches or exceeds the rotational speed of the drill string or drill bit, can include a dynamically adjustable articulated joint having a plurality of elements that deform in response to an excitation signal, can include adjustable independently rotatable rings for selectively tilting the bit, and/or can include a plurality of selectively extensible force pads. The force pads are actuated by a shape change material that deforms in response to an excitation signal. A method of directional drilling includes continuously cycling the position of the steering unit based upon the rotational speed of the drill string and/or drill bit and with reference to an external reference point.

Abstract: Casing cutter for severing multiple tubulars in a well bore has a pair of cutter blades pivotally mounted on a support body. The blades are pivotally mounted for gradual movement outside of the support body when downward force is applied to proximate ends of the cutter blades. The support body is rotated inside the innermost of the multiple tubulars, while the cutter blades sever the tubulars of progressively increasing diameter. Should the cutter blades or pivotal connections become unusable, the tool body can be rotated about the vertical axis and secured to a downhole string by the opposite end. A substitute pair of cutter blades are then engaged on the tool body and operated to cut the casings similar to the first set of the cutter blades.

Abstract: A bottom hole assembly for drilling a cavity including a chassis configured to rotate is provided. The chassis may include a conduit, a circuit, a pressure transfer device, a plurality of pistons, a plurality of valves, and a plurality of cutters. The conduit may accept a first flow of a primary fluid. The circuit may have a second flow of a secondary fluid. The pressure transfer device may be configured to transfer pressure between the flows. The pistons may be operably coupled with the circuit, and each piston may be configured to move based at least in part on a pressure of the circuit at that piston, with the valves possibly configured to control a pressure of the circuit at each piston. Each cutter may be coupled with one of the pistons.

Abstract: A drilling system includes a steerable bottomhole assembly (BHA) having a steering unit and a control unit that provide dynamic control of drill bit orientation or tilt. Exemplary steering units can adjust bit orientation at a rate that approaches or exceeds the rotational speed of the drill string or drill bit, can include a dynamically adjustable articulated joint having a plurality of elements that deform in response to an excitation signal, can include adjustable independently rotatable rings for selectively tilting the bit, and/or can include a plurality of selectively extensible force pads. The force pads are actuated by a shape change material that deforms in response to an excitation signal. A method of directional drilling includes continuously cycling the position of the steering unit based upon the rotational speed of the drill string and/or drill bit and with reference to an external reference point.

Abstract: An expandable drilling apparatus includes a main body comprising a central bore and at least one axial recess configured to receive an arm assembly operable between a retracted position and an extended position, a biasing member to urge the arm assembly into the retracted position, a drive position configured to thrust the arm assembly into the extended position when in communication with drilling fluids in the central bore, a selector piston translatable between an open position and a closed position, wherein the selector piston is thrust into the open position when a pressure of the drilling fluids exceeds an activation value, wherein the drilling fluids are in communication with the drive piston when the selector piston is in the open position, and a selector spring configured to thrust the selector piston into the closed position when the pressure of the drilling fluids falls below a reset value.

Abstract: A drilling apparatus includes a tubular body including an upper connection and a lower connection with a drill bit disposed thereon, and an axial borehole therethrough, wherein the upper connection is configured to attach to a drillstring, primary cutter blocks coupled to the tubular body and configured to selectively expand radially therefrom. The drilling apparatus further includes backup cutter blocks coupled to the tubular body and configured to selectively expand radially therefrom, and an activation system configured to selectively expand and collapse the primary and backup cutter blocks in response to changes in weight applied to the primary and backup cutter blocks.

Abstract: An expandable downhole tool comprises a tubular body, at least one moveable arm disposed within the tubular body and being radially translatable between a retracted position and a wellbore engaging position, and at least one piston operable to mechanically support the at least one moveable arm in the wellbore engaging position when an opposing force is exerted. A method of reaming a formation to form an enlarged borehole in a wellbore comprising disposing an expandable reamer in a retracted position in the wellbore, expanding at least one movable arm of the expandable reamer radially outwardly into engagement with the formation, reaming the formation with the at least one moveable arm to form the enlarged borehole; and mechanically supporting the at least one moveable arm in the radially outward direction during reaming.

Abstract: A drill bit for drilling a borehole in an object, the drill bit having a central longitudinal axis and comprising a bit body provided with a central shank for connecting the drill bit to a drilling system. The drill bit further comprises at least one cutting arm, each cutting arm being provided with a set of cutters for cutting the object and being coupled to the bit body allowing the cutting arm to pivot between a radially retracted position and a radially expanded position.

Abstract: An under reamer for expanding a borehole through an earthen formation is taught. The under reamer includes: a mandrel including an end for connection into a drill string and an opposite end and a housing including an inner bore, telescopically disposed over the mandrel and axially moveable relative to the mandrel but rotationally moveable with the mandrel. A plurality of under reamer arms are carried on the housing, the under reamer arms are formed as blocks including cutter-supporting portions in which poly-crystalline diamond compact cutters are mounted. The under reamer arms are moveable by driving the housing axially over the mandrel between a retracted position extending into the bore of the housing and an expanded position wherein the under reamers arms are pivoted out of the housing inner bore and supported therebehind by the mandrel such that the cutter-supporting portions are exposed for use to enlarge a borehole.

Abstract: An expandable downhole tool comprises a tubular body having an axial flowbore extending therethrough, at least one moveable arm, and a selectively actuatable sleeve that prevents or allows the at least one moveable arm to translate between a collapsed position and an expanded position. A method of expanding the downhole tool comprises disposing the downhole tool within the wellbore, biasing the at least one moveable arm to a collapsed position corresponding to an initial diameter of the downhole tool, flowing a fluid through an axial flowbore extending through the downhole tool while preventing the fluid from communicating with a different flowpath of the downhole tool, allowing the fluid to communicate with the different flowpath by introducing an actuator into the wellbore, and causing the at least one moveable arm to translate to an expanded position corresponding to an expanded diameter of the downhole tool.

Abstract: A bottomhole assembly (BHA) for single trip sidetracking operations has a mill for forming an open hole section in a cased wellbore and a steering unit for controlling drill bit orientation. During use, the drilling system is assembled at the surface and tripped into the wellbore. The mill is positioned adjacent a kick-off point and operated to form an open hole section. Thereafter, the drill bit is positioned adjacent the open hole section. An exemplary steering unit includes one or more force application members that, when energized, displace the drill bit such that the bit is pointed in a specified direction into the open hole section. The steering unit also includes one or more force application members that facilitate directional drilling through the open hole section. Other suitable steering units can employ devices that alter the BHA centerline geometry.

Abstract: A system is provided (1) for increasing the diameter of at least a portion of a well bore, the system being intended to be attached to a drill pipe (3), the system having a support element (10) bearing cutting arms (13, 14) which is movably mounted with respect to a body (4) and wherein the arms and the chamber (6) of the body (4) are designed so as to cooperated. A method is also provided for increasing the diameter of at least a portion of a well bore by drilling.

Abstract: A roller cone bi-center bit for economically drilling an enlarged borehole below casing in earth formation is provided. The bi-center bit includes a rolling cone cutter or other appropriate cutter to enlarge a pilot bore also made by rolling cone or other type of cutters. The bit comprises a single-diameter body with a recess to accommodate the trailing cutter which enlarges the pilot bore. The bi-center bit may also provide the ability to change out the cutters efficiently in the field. The cutters are oriented to enhance drilling out the cement plug at the bottom of the casing. The cone cutter may be also be mounted on segments which are designed to be easily removed for replacement or adjustment in position in the field.

Abstract: A coalbed methane borehole pipe liner perforation system comprises a plastic pipe punch that slips down inside a coalbed methane production borehole lined with a non-perforated plastic pipe. A ground-penetrating radar is used inside the plastic-pipe lined borehole to determine which sections of the pipe are in contact with groundwater. The punch is then operated along the length of the plastic-pipe lined borehole to perforate it for methane-gas collection wherever such groundwater is not present. A radar survey to determine groundwater contact can be made simultaneously in combination with the punching of liner pipe perforations, or earlier in a separate operation.

Abstract: System (1) for increasing the diameter of at least a portion of a well bore, the system being intended to be attached to a drill pipe (3), the system having the improvement that the support element (10) bearing the curring arms (13, 14) is movably mounted with respect to the body (4) and that the arms and the chamber (6) of the body (4) are designed so as to cooperate.

Abstract: An underreamer (5) is formed from a tubular body (10) having a longitudinal bore therethrough, and providing an integral piston actuator (20) responsive to hydraulic pressure to move cutters (40) into engagement with the well bore and springs (60) to resist premature engagement of the cutter arms (40) and to return the cutters (40) to the body upon conclusion of the underreaming job. Skewed longitudinal grooves (45) are formed in the tubular body thereby permitting the flowpath through the underreamer to provide substantially the same inner diameter throughout the tool (5).

Abstract: A drilling apparatus for underreaming includes a top sub, a pressure sleeve mated to the top sub, and a blade body mated to the pressure sleeve. A pilot bit is mated to the lower end of the blade body. A plurality of movable cutting blades are pivotably attached to the blade body by pivot pins. Each of the pins is inserted through the blade body and the cutting blade. Slidable covers, held in place by the pressure sleeve, are used to retain the pins. A mandrel is centrally positioned with respect to the pressure sleeve and the blade body and is axially movable therein. Each of the cutting blades includes an end which is operatively associated with channels transversely formed on one end of the mandrel. Movement of the mandrel in a first axial direction effects retraction of the cutting blades. Movement of the mandrel in a second axial direction effects extension of the cutting blades. The mandrel is held in its blade-retracting position by the biasing force of a spring.

Abstract: A downhole unit for use in subsurface boreholes, for example a bias unit for imparting a lateral bias to the drill bit to control the direction of drilling, includes a main body and a number of pads pivotally mounted on the main body for engagement with the walls of the borehole. A thrust member is disposed inwardly of each pivotal pad and is movable along a guide passage in the main body to transmit movement to the pad. Each thrust member is movable by hydraulic pressure and a fluid-tight sliding seal is provided between the thrust member and its guide passage. The outer surface of each thrust member or the inner surface of the guide passage, or both, is in the form of a portion of a toroid centred on the pivot axis of the respective pad so as to minimise lateral movement of the seal as the thrust member moves along the passage. This also allows relative displacement between the thrust member and pad to be avoided, so that the thrust member can be integral with the pad or rigidly connected to it.

Abstract: A method to drill a hole in the soil by a bit assembly and a bit assembly comprising a ring-shaped bit (2) to drill the outer circle of the hole and to which a protection tube system (4), mounted in the hole while drilling, is coupled, and a cylindric inner bit (1) to drill the center portion of the hole, from which bit at least the rotative motion is transmitted to the outer bit (2). Drilling by the outer bit (2) and pulling out the protection tube (4) are disconnected upon need by reverse rotation of the inner bit, whereafter drilling is continued with the inner bit (1) only.

Abstract: A section mill for cutting through well casing, the mill including multiple sets of cutting blades which are selectively engaged to continue cutting operations as blades dull. The cutting blade sets are selectively indexable such that as a first set dulls or fails a succeeding set can be utilized following retraction of the first set. The section mill includes a central mandrel having offset cammed surfaces which engage the cutting blades and cause them to expand outwardly. The mandrel is axially displaceably by a piston affected by hydraulic pressure. As the mandrel is axially displaced the indexed cutting blades are expanded by the cammed surface. Indexing is accomplished by a cam drum which allows the mandrel to be rotated relative to the cutting blades in order to align the next cammed surfaces with their respective cutting blades.

Abstract: An underreamer tool has a body with upper and lower portions having an upper cutter blade slot extending transversely through the upper portion and a lower cutter blade slot extending transversely through the lower portion at a right angle thereto. The upper and lower portions have central bores separated by a wall and connected by upper and lower fluid flow passageways bypassing the cutter blade slots. An upper pair of cutter blades mounted in the upper cutter blade slot and a lower pair of cutter blades mounted in the lower cutter blade slot move between a retracted position within the slots and an extended position outward therefrom. An upper piston in the central bore above the upper cutter blade slot has its bottom end engaged on the upper cutter blades and a lower piston in the central bore above the lower cutter blade slot has its bottom end engaged on the lower cutter blades.

Abstract: A downhole cutting tool, specifically adapted to function as an enhanced diameter clean-out tool, includes longitudinal bores which are opened to fluid flow when cutting members are moved to their extended positions. Upper and lower subassemblies are connected through an adapter which establishes an angular offset between an upper pair of extendible members and a lower pair of extendible members, which upper pair functions as a stabilizing structure to stabilize rotation of the tool and which lower pair functions as an enhanced diameter cutter.

Abstract: The invention herein relates to an undercutting device which is provided with a substantially tubular body adapted to be placed within a parallel-sided hole. A rotary percussion head is provided at one end of the body and has one or more cutting tools which extend radially therefrom at an obtuse angle and which cutting tools are adapted to cut outwardly from the radius of the body, means are provided for rotating the head about the axis of the body and for operating the percussion head at one predetermined depth in the hole so that the cutting tools may act on the wall of the parallel-sided hole.