Abstract: A drilling system comprising a drive shaft having a fluid flow conduit extending therethrough; a drill bit mounted for rotation by the drive shaft and having a bit face which, in use, contacts a formation to be drilled, and including a fluid flow passage with an outlet near the center of the bit face; a first fluid flow line extending from the outside of the drive shaft to the flow passage in the drill bit; and a second fluid flow line extending from the outside of the drive shaft to the flow conduit. A method of drilling a well using such a system comprise positioning the system in a borehole; rotating the drive shaft to rotate the bit; urging the bit against the formation to be drilled; and pumping drilling fluid down the borehole so as to pass though the first flow line and to exit the fluid flow passage in the drill bit via the outlet, flow over the bit face and pass into the fluid low conduit via the second fluid flow line.

Abstract: A turbine drill motor capable of operation at ultra-high rotary speeds (i.e., in excess of 1000 rpm, which is very high for turbine drill motors), with a high-pressure jet-assist functionality for drilling and well service applications. The ultra-high rotary speed enables fast penetration with diamond bits, while the high-pressure jet-assist ensures adequate cooling and cuttings removal. In an exemplary embodiment, such a turbine drill motor includes a bypass channel to divert a portion of the driving fluid supply when the bit is off-bottom, to limit the no-load runaway speed of the turbine. Serial and parallel flow paths can be accommodated, and different drill bits for cutting and well-bore servicing are disclosed.

Abstract: The present invention concerns the down hole motors used in the oil prospecting industry to drive drill bits for drilling the ground at great depths. The down hole motor (1) comprises a drive shaft (5) held in the motor body (3) by an axial thrust bearing (6) and by a radial bearing (7). The radial bearing (7) is a tubular member whose interior surface is coated with an anti-abrasion layer (11) formed by laser-assisted facing directly inside an alloy steel radial bearing body (10). The thickness of the facing layer is then reduced by removing material by means of a cutting tool. This produces a radial bearing (7) that is relatively insensitive to drilling mud and confers great reliability on the down hole motor (1).

Abstract: A downhole drilling motor comprising a housing and a shaft extending within the housing, wherein the shaft is movable relative to the housing. Further, a conducting path extends within the housing between a first axial position and a second axial position. The conducting path comprises a housing conductor associated with the housing and a shaft conductor associated with the shaft, wherein the shaft conductor is capable of a movement relative to the housing conductor. An assimilating connector is interposed between the housing conductor and the shaft conductor for conductively connecting the housing conductor with the shaft conductor and for assimilating the movement of the shaft conductor relative to the housing conductor. The assimilating connector includes one or more of a rotary movement assimilating connector, a longitudinal movement assimilating connector and a transverse movement assimilating connector.

Abstract: A generator (10) is provided for positioning downhole in a drill string (12) to generate power powering one or more downhole tools (16). The generator includes a progressive cavity housing (28) and a progressive cavity rotor (30) which rotates in response to fluid passing through the progressive cavity housing. A restriction (36) in the annulus downstream from the ports controls the fluid flow in the annulus and past the restriction, and thereby the fluid flow through the progressive cavity housing. The generator may provide either hydraulic or electrical power, or both, powering the one or more tools.

Abstract: Methods and apparatuses to direct a drill bit of a directional drilling assembly are disclosed. The methods and apparatuses employ the use of bi-directional actuators that are capable of displacing a hybrid steering sleeve in positive and negative directions. The bi-directional actuators are capable of greater control and precision in their actuations than traditional “engaged-disengaged” unidirectional actuators, thereby allowing for more precise directional drilling operations. The bi-directional actuators are preferably driven by drilling fluids and may optionally be shielded to lessen the erosive effects thereof.

Abstract: The invention relates to a drive system, in particular a downhole drilling assembly (10). In the preferred embodiment, a bearing mechanism (14,24) of the assembly (10) is isolated from a gear mechanism (20) of the assembly (10), to prevent failure of the bearing mechanism (14, 24) due to vibration and heat generated by the gear mechanism (20) in use. A lower bearing unit (24) of the bearing mechanism (24) is coupled to the gear mechanism (20) by a shock eliminating coupling assembly (22), which prevents the transmission of shock loads to the gear mechanism (20). Also, the gear mechanism (20) is coupled through a shock eliminating coupling assembly (18) to a turbine (16) and thus to an upper bearing unit (14). Sealing assemblies (60, 116) are provided for the gear mechanism (20) and the upper bearing unit (14) to prevent drilling fluid ingress and consequent damage. The assembly (10) may also carry a torsionally flexible drive shaft (46).

Abstract: In one aspect of the invention, a downhole tool string component has at least one end adapted to connect to an adjacent tool sting component and a bore adapted to accommodate a flow of drilling fluid. A turbine is disposed within the bore and an actuating assembly is arranged such that a clutch may mechanically connect and disconnect with the turbine.

Abstract: A thrust bearing assembly comprising a rotating bearing runner and a stationary bearing carrier, the carrier defining a plurality of thrust pad sites annularly around the carrier, with a thrust pad disposed at a site and with the carrier constraining movement of the thrust pad in a direction generally radial to the longitudinal axis of the runner while allowing the thrust pad to move in a direction generally parallel to the longitudinal axis. An embodiment comprises a rotating bearing runner having a wear resistant face and a stationary bearing carrier defining cavities disposed annularly around the carrier. A deflection element (e.g., Belleville washer) is disposed in a cavity and a pad is disposed over the deflection element. The pad is at least partially disposed within the cavity. The wear resistant face contacts the pad. Another embodiment rigidly connects pads disposed on opposite sides of a stationary bearing carrier.

Abstract: A downhole motor assembly for driving a drill bit. The assembly includes a hydraulic drive section with a stator and a rotor located inside the stator to form a flow path between the stator and the rotor. Fluid flowing through the flow path in response to a pressure differential across the hydraulic drive section creates an operative force to rotate the drill bit. The assembly also includes a regulation mechanism that includes a valve and a fluid flow diversion bore for diverting at least some fluid from the flow path when the pressure differential across the hydraulic drive section is greater than or equal to a transition pressure differential.

Abstract: A while-drilling tool comprising a motor, a transmission coupled to the motor, and a pump comprising a first piston disposed in a first chamber and a second piston disposed in a second chamber and coupled to the first piston. A planetary roller-screw is coupled between the pump and the transmission. A valve block is configured to fluidly communicate with the first and second pump chambers, a borehole in which the while-drilling tool is configured to be positioned, and a formation penetrated by the borehole.

Abstract: In one aspect of the present invention, a drill bit has a jack element that is substantially coaxial with an axis of rotation of the drill bit and the jack element has an asymmetrical distal end that extends beyond a working face of the drill bit. A turbine is located within a bore formed in the drill bit and a flow valve is actuated by the turbine. The flow valve is adapted to route a drilling fluid in the bore into a porting mechanism adapted to extend the jack element farther beyond the working surface of the drill bit. The turbine is also adapted to rotate the jack element at variable speeds.

Abstract: The present invention relates to systems and methods for controlling downhole motors. One aspect of the invention provides a valve-controlled downhole motor including: a downhole motor and a spool valve. The downhole motor includes a sealed chamber having a first port and a second port, a stator received within the sealed chamber, and a rotor received within the stator. The spool valve includes a barrel and a spool received within the barrel. The barrel includes an inlet port, an exhaust port, a first feed port, a second feed port, a first return port, and a second return port. The inlet port is located in proximity to the first feed port and second port. The exhaust port is located in proximity to the first return port and the second return port. The spool includes a first gland and a second gland.

Abstract: A drilling assembly in an elongated hole including a housing defining an interior with a plurality of motor stages in the interior. Each motor stage has at least one blade with supporting platform surfaces. A casing within the interior surrounds the plurality of motor stages and defines an annular flowpath with the housing. The casing also defines at least one offtake passage adjacent each motor stage. A shielding fluid passes through the annular flowpath and, in turn, the at least one offtake of each motor stage to coat and protect the at least one blade and supporting platform surfaces. A driving fluid passes through the casing for propelling the at least one blade of each motor stage. Preferably, the shielding fluid is at a relatively higher pressure than the driving fluid with a substantially constant ratio maintained between the between the shielding fluid and the driving fluid.

Abstract: A turbo-gear supplied with operating fluid for driving a drill bit is proposed. It preferably comprises a non-rotatable casing, an upper shaft rotatably mounted in the casing, coupled with blades configured to receive pressure of the operating fluid causing rotation of the upper shaft, a lower shaft mounted in the casing, having inside a cylindrical channel, an intermediate shaft rotatably mounted in the casing, disposed below the upper shaft and above the lower shaft. The shafts are associated with each other through conventional gears having predetermined transmission coefficients. The inner space of the turbo-gear is configured to pass the operating fluid therethrough. Preferably, the turbo-gear is combined with a bushing-connector shaped as a hollow cylinder, having means for assembling with the turbo-gear and the bit. The turbo-gear is assembled with a non-rotatable string of pipes, through which the operating fluid is supplied. The turbo-gear allows extending the lifespan of pipes.

Abstract: A thrust bearing assembly comprising a rotating bearing runner and a stationary bearing carrier, the carrier defining a plurality of thrust pad sites annularly around the carrier, with a thrust pad disposed at a site and with the carrier constraining movement of the thrust pad in a direction generally radial to the longitudinal axis of the runner while allowing the thrust pad to move in a direction generally parallel to the longitudinal axis. An embodiment comprises a rotating bearing runner having a wear resistant face and a stationary bearing carrier defining cavities disposed annularly around the carrier. A deflection element (e.g., Belleville washer) is disposed in a cavity and a pad is disposed over the deflection element. The pad is at least partially disposed within the cavity. The wear resistant face contacts the pad. Another embodiment rigidly connects pads disposed on opposite sides of a stationary bearing carrier.

Abstract: Disclosed herein is a downhole mud motor. The mud motor includes, a stator, a rotor in operable communication with the stator, a polymer in operable communication with the stator and the rotor, and a plurality of carbon nanotubes embedded in the polymer.

Abstract: The present invention relates to devices and methods for conveying power and/or data signal along a wellbore bottomhole assembly (BHA) having a steering unit, a bidirectional data communication and power (“BCPM”) unit, a sensor sub, a formation evaluation sub, stabilizers. A power and/or data transmission line enables power transfer and two-way data exchange among these BHA components. In one embodiment, a drilling motor includes a transmission unit that transmits power and/or data between modules adjacent the motor via conductive elements in the rotor and/or the stator. A power/data transfer device is adapted to transfer power and/or data between the rotating and non-rotating sections of the transmission unit. The tooling and equipment making up the BHA can be formed as interchangeable modules. Each module can include electrical and data communication connectors at each of their respective ends so that power and data can be transferred between adjacent modules via modular threaded connections.

Abstract: A fluid driven drilling motor and system includes a flex shaft between the rotor and a cylindrical flow collar. The end of the flow collar opposite from the flex shaft has a bore in fluid communication with a drill bit. Ramped apertures are formed in the side wall of the flow collar. The ramped apertures are in fluid communication with the bore. Drilling fluid flowing under pressure down past the flex shaft is directed and drawn into the ramped apertures along a fluid flow path which spirals downwardly and radially inwardly of the flow collar so as to then flow into the bore. The pressure loss associated with drawing the drilling fluid down to the drill bit is thereby minimized.

Abstract: In at least one example, an isolation system includes at least one air bladder assembly including at least one air bladder and at least one coupling member coupling the air bladder to a drill head, wherein the air bladder is configured to compress and expand to counter oscillating forces generated by the drill head.

Abstract: An exemplary embodiment of the jet motor includes a control sleeve, and power shaft having at least one opening thereon. The power shaft is rotatable in relation to the control sleeve. The power shaft has a central longitudinal shaft axis and upper and lower ends. The at least one opening in the power shaft generates rotational torque when acting in cooperation with the control sleeve. The jet motor connects to a member that is in fluid communication with the source of drilling or cleaning fluid. Drilling or cleaning fluid pressure is directed to the at least one opening in the power shaft. The power shaft having at least one opening having an opening axis and an interior opening. The at least one opening may be acutely oriented with respect to a plane extending along the power shaft's central longitudinal axis wherein the plane intersects the opening axis at the interior opening. The at least one opening may be oriented toward the upper end of the power shaft to provide downward force.

Abstract: The invention comprises a downhole jet motor, and a method of using same, that can be utilized to drill or to clean a well bore or tubing. The jet motor comprises a power shaft partially surrounded by a control sleeve defining a blind annular space, closed at the upper end and open at the lower end to allow fluid discharge. At least one opening is provided in the drive shaft wall extending radially within the annulus region. Drilling or cleaning fluid pressure is directed to the at least one opening in the power shaft. The control sleeve provides a reaction structure in relation to fluid discharged from the at least one opening producing rotation of the drive shaft in relation to the control sleeve.

Abstract: A technique that is usable with a well includes running a motor into the well and actuating the motor to turn a drill bit. The motor is used to pump well fluid from the well.

Abstract: In one aspect of the present invention a hammer assembly comprises a substantially coaxial jack element with a distal end extending beyond a working face of a drill bit. A porting mechanism within the bore comprises a first and second disc substantially contacting along a flat interface substantially normal to the axis of rotation. The first disc is attached to a turbine which is adapted to rotate the first disc with respect to the second disc. The first disc comprises a first set of ports adapted to align and misalign with a second and third set of ports in the second disc. As the first disc rotates, the sets of ports are adapted to route a drilling fluid into a piston chamber where the porting mechanism causes the jack element to repeatedly extend further beyond the working surface of the drill bit at a constant frequency.

Abstract: An anti-surge/reverse thrusting tool for reducing the forces on a drill bit used in subterranean well drilling operations along with methods for drilling wells using a drill string employing the tool. The tool utilizes the pressure differential between drilling fluid flowing through the tool and the fluid located in the well bore annulus proximate the tool to reduce the likelihood of drill bit stall. The tool generally comprises an outer housing and a piston assembly that is axially shiftable relative to the housing.

Abstract: An apparatus (50) for drilling a wellbore that transverses a subterranean hydrocarbon bearing formation. The apparatus (50) includes a drill string (52) having an inner fluid passageway (66). A drill bit (64) is disposed at a distal end of the drill string (52) and is operable to rotate relative to at least a portion of the drill string (52). A fluid motor (54) is disposed within the drill string (52) and is operable to rotate the drill bit (64) in response to a circulating fluid received via the inner fluid passageway (66) of the drill string (52). The fluid motor (54) has a stator (68) with (n) lobes and a rotor (70) with (n?1) lobes. The stator (68) includes an inner surface formed from a first material and the rotor (70) includes an outer surface formed from a second material that is dissimilar to the first material.

Abstract: A method is disclosed for running a completion string, such as casing, into a predrilled wellbore while allowing rotation of a downhole component with respect to the completion string. The downhole component may be a drill shoe or reamer shoe for example. There is also disclosed a drillable or millable drive assembly for driving the rotation of a portion of the casing assembly and other applications thereof.

Abstract: Systems and methods for preventing slippage and rotation of components installed in a tubular housing member and/or along a rotatable tubular shaft during drilling operations are disclosed herein. The housing and/or rotatable shaft include a shoulder disposed proximate to one end. An adjustable member is secured proximate to the opposite end. One or more components are installed, covering a first portion of the surface between the adjustable member and shoulder. One or more spacing members are installed to cover substantially all of the remaining surface. The adjustable member is tightened such that the adjustable member and the shoulder apply a compressive axial load to the components and spacing members, causing frictional forces between adjacent objects greater than the torque acting on the housing and/or tubular shaft, causing each component to remain stationary with respect to the surface to which it is secured.

Abstract: A method of making a drilling motor for use in a wellbore includes defining a profile for an inner surface of a stator; configuring at least one cutting element on a support to at least partially form the profile; translating the support through a bore of the stator such that the at least one cutting element engages the inner surface of the stator; and forming a helical passage using the at least one cutting element by causing relative rotation between the stator and the support.

Abstract: A method of adjusting backlash in a down hole bearing assembly involves providing in side by side relation on an outer surface of an inner mandrel a circumferential first threaded seat adapted to accommodate a first nut which engages the first threaded seat by rotation in a first rotational direction and becomes disengaged by rotation in a second rotational direction and a circumferential second threaded seat adapted to accommodate a second nut which engages the second threaded seat by rotation in the second rotational direction and becomes disengaged by rotation in the first rotational direction. The first nut is threaded onto the first threaded seat to place the inner mandrel in tension with a first stop and a second stop engaging a thrust bearing. The second nut is coupled to the first nut to resisting any rotational movement of the first nut in the second rotational direction.

Abstract: A universal joint assembly includes an assembly housing, an assembly cap coupled to the assembly housing, a rotatable mandrel, a plurality of substantially spherical drive balls, and a floating washer. The assembly housing has a plurality of pockets formed in an interior surface of the assembly housing. The rotatable mandrel is fitted within a cavity defined by the assembly housing and the assembly cap and has a plurality of pockets configured to partially receive the drive balls. The substantially spherical drive balls are rotatable within the cavity about a central axis of the mandrel. A substantially circular groove formed in the cavity is defined by a proximal end of the assembly cap and an interior wall and a shoulder of the assembly housing. The floating washer is disposed within the substantially circular groove and configured to radially displace within the groove.

Abstract: A drilling motor includes an upper end connection adapted to connect to a drill string, and a lower end connection adapted to connect to a drill bit, a thrust bearing assembly having a plurality of stages assembled in a stack, each stage including at least one rotating inner bearing subassembly configured to contact at least one corresponding stationary outer bearing subassembly, wherein axial loads among the plurality of stages are substantially equal under normal operating conditions.

Abstract: A device for boring a well with casing. The device is attached to a motor that has a power shaft for imparting rotational movement. The device comprises a driver operatively connected to the power shaft, with the driver containing a cylindrical body, a first bit having a first end connected to the driver so that rotational movement of the driver is imparted to the first bit, and a sleeve disposed about the power shaft, and wherein the sleeve has a radial shoulder. The device further includes casing attached to the sleeve, and wherein the casing is designed to be permanently placed within the well once the boring is completed. The device further comprises a housing disposed about the driver, a second bit attached to the housing, and a planetary gear anchored to the radial shoulder, and wherein the planetary gear is adapted for imparting rotation from the driver to the housing in a counter radial direction.

Abstract: In one aspect of the present invention, a downhole drill string assembly comprises a bore there through to receive drilling fluid. A turbine may be disposed within the bore and exposed to the drilling fluid. At least one flow guide may be disposed within the bore and exposed to the drilling fluid wherein the flow guide acts to redirect the flow of the drilling fluid across the turbine. The flow guide may be adjusted by an actuator. Adjustments to the flow guide may be controlled by a downhole telemetry system, a processing unit, a control loop, or any combination thereof. In various embodiments the turbine may comprise rotatable turbine blades.

Abstract: In one aspect of the present invention, a downhole drill string assembly comprises a bore there through to receive drilling fluid. A turbine may be disposed within the bore and exposed to the drilling fluid. At least one flow guide may be disposed within the bore and exposed to the drilling fluid wherein the flow guide acts to redirect the flow of the drilling fluid across the turbine. The flow guide may be adjusted by an actuator. Adjustments to the flow guide may be controlled by a downhole telemetry system, a processing unit, a control loop, or any combination thereof. In various embodiments the turbine may comprise rotatable turbine blades.

Abstract: A fluid actuated downhole tool for inducing movement of a downhole apparatus is described. The tool comprises a body for coupling to downhole apparatus, the body being adapted to accommodate now of fluid therethrough and including a flow-modifying arrangement for modifying the flow of fluid through the body. The flow-modifying arrangement is configurable in an inactive configuration and in an active configuration. The fluid activated tool is selectively operated from the surface by varying an operating condition which causes the flow through the tool to either bypass or flow through the flow-modifying arrangement to induce movement of the downhole apparatus.

Abstract: A drilling unit containing a combined pilot bit and reamer. The drilling unit includes a housing containing a mud motor and a pilot bit extending from its distal end. A reamer is mounted to the housing. The mud motor turns the pilot bit while the reamer is turned either by the mud motor or as the drill string is rotated from the surface. The well bore is drilled and reamed in one pass. By positioning the reamer between the pilot bit and the mud motor, the mud motor must only pass through the larger reamer bore rather than the smaller pilot hole. This will allow larger mud motors to be used than would otherwise be possible. In one embodiment, the pilot bit is offset relative to the center of the end of the drill housing, providing increased tangential speed at the point of impact between the pilot bit and formation.

Abstract: Thrust-bearing assemblies, and thrust-bearing apparatuses and downhole motors incorporating such thrust-bearing assemblies are disclosed. In one aspect of the present invention, a thrust-bearing assembly is disclosed. The thrust-bearing assembly comprises a seat including a generally spherical surface at least partially defining a recess. A bearing support is positioned within the recess. The bearing support includes a generally spherical surface configured so that the bearing support is capable of movement with the recess of the seat. At least one bearing element may be mounted to the bearing support. The thrust-bearing assembly further includes a motion-limiting structure configured to limit relative movement between the bearing support and the seat. The motion-limiting structure does not extend between the generally spherical surface of the seat and the generally spherical surface of the bearing support.

Abstract: A method of running a tubular string into a wellbore comprises running a bore-lining tubular string into a wellbore substantially without rotation, while rotating a cutting structure at a distal leading end of the tubular string. Other methods provide for rotation of the string and the provision of a non-rotating stabiliser towards the leading end of the string.

Abstract: A downhole drilling motor beating assembly includes a tubular mandrel adapted to connect to a rotational power output of downhole motor. The bearing assembly includes a mandrel having: an upper end proximal to the downhole motor, a lower end with a pin connection distal from the motor, and a longitudinal passage through the mandrel from the upper end to the lower end. The assembly further includes at least one circumferential ring projecting radially outward from an other surface of the tubular mandrel. The ring has and upper shoulder and a lower shoulder and a radial surface. A circumferential upper thrust bushing contacts the upper shoulder of the ring and a circumferential lower thrust bushing contacts the lower shoulder of the ring. An upper thrust beating contacts the upper thrust bushing and a lower thrust bearing contacts the lower thrust bushing. A tubular bearing housing includes a longitudinal passage from an upper end of the housing to a lower end of the housing.

Abstract: A nano particle reinforced polymer element of a stator and rotor assembly for a power section of a positive displacement fluid motor or a progressive cavity pump. Nano-sized particles are blended with an uncured polymer to improve the physical and chemical properties of the polymer. The use of nano-sized particles reduces the quantity of reinforcement material required to manufacture the polymer for the stator and rotor assembly and lowers the viscosity of the uncured polymer to improve manufacturing characteristics. The use of chemically functionalized nano particles improves the chemical and physical characteristics of the polymer.

Abstract: A method and apparatus for changing the speed of a drill bit down hole in a fluid-actuated motor, including a positive displacement motor and a hydraulic motor, is disclosed. The apparatus comprises a bypass valve installed in the motor for controlling flow through and around the power section of the motor. When closed, the bypass valve forces all fluid to flow through the power section of the motor, imparting maximum speed to the drill bit. When opened, a portion of the fluid flow is allowed to flow around the power section of the motor, thereby reducing the speed of the drill bit. The bypass valve may be opened or closed mechanically, electrically, hydraulically, pneumatically, or by any other means, including a removable plug.

Abstract: Hydrodynamic bearing assemblies and apparatuses are disclosed. Such hydrodynamic bearing assemblies may be employed in bearing apparatuses for use in downhole motors of a subterranean drilling system or other mechanical systems. In one embodiment of the present invention, a hydrodynamic bearing assembly includes a plurality of bearing segments distributed circumferentially about an axis. Each bearing segment includes a superhard bearing surface. The plurality of bearing segments define a plurality of seams. Each seam is formed between circumferentially-adjacent bearing segments of the plurality of bearing segments. Further embodiments of the present invention include hydrodynamic bearing apparatuses and downhole motors that may utilize any of the disclosed hydrodynamic bearing assemblies.

Abstract: A downhole motor assembly for driving a drill bit. The assembly includes a hydraulic drive section with a stator and a rotor located inside the stator to form a flow path between the stator and the rotor. Fluid flowing through the flow path in response to a pressure differential across the hydraulic drive section creates an operative force to rotate the drill bit. The assembly also includes a regulation mechanism that includes a valve and a fluid flow diversion bore for diverting at least some fluid from the flow path when the pressure differential across the hydraulic drive section is greater than or equal to a transition pressure differential.

Abstract: A bearing assembly for use with a mud motor includes a two-piece mandrel and a housing. Two radial bearings and a triple stack axial thrust on-bottom bearing are disposed between the mandrel and housing.

Abstract: In one aspect of the present invention, a drill bit has a jack element that is substantially coaxial with an axis of rotation of the drill bit and the jack element has an asymmetrical distal end that extends beyond a working face of the drill bit. A turbine is located within a bore formed in the drill bit and a flow valve is actuated by the turbine. The flow valve is adapted to route a drilling fluid in the bore into a porting mechanism adapted to extend the jack element farther beyond the working surface of the drill bit. The turbine is also adapted to rotate the jack element at variable speeds.

Abstract: In one aspect of the present invention a downhole tool string has a rotor secured within a bore and connected to a jack element that is substantially coaxial with the rotor. A portion of the jack element extends out of an opening formed in a working face of a drill bit located at the bottom of the drill string. The jack element is adapted to rotate independent of the drill bit when the rotor and drill bit are in operation.

Abstract: In one aspect of the present invention, a drill bit has a jack element that is substantially coaxial with an axis of rotation of the drill bit and the jack element has an asymmetrical distal end that extends beyond a working face of the drill bit. A turbine is located within a bore formed in the drill bit and a flow valve is actuated by the turbine. The flow valve is adapted to route a drilling fluid in the bore into a porting mechanism adapted to extend the jack element farther beyond the working surface of the drill bit. The turbine is also adapted to rotate the jack element at variable speeds.

Abstract: In one aspect, a downhole assembly has a downhole tool string component with a bore adapted to accommodate drilling mud. A fluid barrier is disposed within the bore and has a cylindrical portion substantially aligned with the bore. A drive shaft is sealed within and substantially coaxial with the cylindrical portion and has a first magnet disposed on its outer surface. A turbine assembly is disposed around the cylindrical portion of the fluid barrier and has an inner diameter and outer surface. The outer surface of the turbine assembly has a plurality of turbine blades. The inner diameter of the turbine assembly has a second magnet disposed within a region defined by the turbine blades and is in magnetic communication with the first magnet of the drive shaft, wherein when the drilling mud engages the turbine blades the first and second magnets rotate the drive shaft with the turbine assembly.

Abstract: A turbodrill has rotor vanes and stator vanes that are asymmetric with respect to each other. The rotor blade on which the rotor vanes are disposed has a reaction of less than about 0.5. A method of designing a turbodrill comprises optimizing a first design of stator vanes and optimizing a second design of rotor vanes using computational fluid analysis.