Abstract: A rotary fluid drive has first and second bodies 20, 120. The second body 120 is rotatable relative to and inside of the first body 20 defining a working fluid space 40 there between. Gates 130 are supported by the first body 20 and lobes 124 are provide on the second body 120. Gate pockets 26 are formed in the first body 20 into which the gates swing when contacted by the lobes 124. The gates 130 and the gate pockets 26 are configured to form a debris chamber 27 there between capable of temporarily accommodating solid debris. Each gate 130 has a plurality of projections 136A with intervening gaps 136B. The gaps form a gate pocket flow path 141. Working fluid flows via each gate pocket flow path 141 into the working fluid space 40 when the associated gate 130 is maximally deflected into its associated gate pocket 26.

Abstract: A steerable drilling apparatus includes a control system inside a cylindrical housing connected to a drill bit having radially-extendable pistons. A fluid-metering assembly directs a piston actuating fluid into fluid channels in the drill bit leading to respective pistons. The control system controls the fluid-metering assembly to selectively allow fluid flow through the fluid channels to the pistons and to exit through orifices in the fluid channels. The selective fluid flow causes the actuated piston to temporarily extend in the opposite direction to a desired wellbore deviation, thereby deflecting the drill bit away from the borehole centerline. An upper member in the fluid-metering assembly can be moved to stabilize, steer, and change TFA within the drill bit. The control system and drill bit are connected so as to facilitate removal to change the drill bit's steering section and cutting structure configuration or gauge simultaneously.

Abstract: A downhole motor rotary drive system including a housing, a rotor rotatably and coaxially disposed within the housing, and an annular space between the rotor and housing. The rotor includes first and second ends, a bore extending between the first and second ends, an inlet port extending from the bore to the annular space, and an outlet port extending from the annular space to the bore. A plurality of gates are disposed within the annular space, each configured to engage the rotor and the housing, and a plurality of lobes extend within the annular space such that the lobes and the gates divide the annular space into a plurality of chambers. A flow path is defined by the annular space between the inlet and outlet ports, and the rotor is configured to rotate relative to the housing when a fluid is circulated along the flow path.

Abstract: A steerable drilling apparatus includes a control system inside a cylindrical housing connected to a drill bit having radially-extendable pistons. A fluid-metering assembly directs a piston-actuating fluid into fluid channels leading to respective pistons. The control system controls the fluid-metering assembly to allow fluid flow to selected pistons, causing the actuated pistons to temporarily extend in the opposite direction to a desired wellbore deviation, thereby deflecting the drill bit away from the borehole centerline. An upper member in the fluid-metering assembly can be moved to stabilize, steer, and change TFA within the drill bit. The control system and drill bit are connected so as to facilitate removal to change the drill bit's steering section and cutting structure configuration or gauge simultaneously. The apparatus may incorporate a fluid filter module mounted to the control system. The pistons may incorporate auxiliary cutting elements to provide near-bit reaming capability.

Abstract: A steerable drilling apparatus includes a control system inside a cylindrical housing connected to a drill bit having radially-extendable pistons. A fluid-metering assembly directs a piston-actuating fluid into fluid channels leading to respective pistons. The control system controls the fluid-metering assembly to allow fluid flow to selected pistons, causing the actuated pistons to temporarily extend in the opposite direction to a desired wellbore deviation, thereby deflecting the drill bit away from the borehole centerline. An upper member in the fluid-metering assembly can be moved to stabilize, steer, and change TFA within the drill bit. The control system and drill bit are connected so as to facilitate removal to change the drill bit's steering section and cutting structure configuration or gauge simultaneously. The apparatus may incorporate a fluid filter module mounted to the control system. The pistons may incorporate auxiliary cutting elements to provide near-bit reaming capability.

Abstract: A system and method for communicating with a downhole tool. A downhole tool includes a downlink receiver and a command actuator. The downlink receiver receives control information, encoded in rotation of the tool, that controls operation of the tool. The downlink receiver includes a rotation sensor and a decoder. The rotation sensor senses rotation of the tool about a longitudinal axis. The decoder demarcates fields of the control information based on rotation state transitions sensed by the rotation sensor. The rotation state transitions are transitions between a rotating state and a non-rotating state. The decoder also decodes a control value for controlling the tool based on a duration of a field of the control information. The control value is wholly encoded in the field, and the field is encoded as a non-rotating state of the tool. The command actuator applies the control value to control operation of the tool.

Abstract: Apparatus and methods for increasing the torque capacity of connections between tubular members. In some embodiments, the connection is threaded. The apparatus may include a first tubular end having a torque member moveable thereon. A second tubular end is made up with the first tubular end. The torque member is moveable back toward the second tubular end. The torque member can be moved into engagement with the second tubular end, and then torqued against the second tubular end. A first torquing interface is provided between the first tubular and the second tubular by making up their respective ends, and a second torquing interface is provided therebetween by torquing the torque member against the second tubular end. A torque capacity of the made up connection is increased thereby.

Abstract: In a mud-lubricated bearing assembly for a downhole motor, a mechanical seal is provided between the mandrel and the lower end of the bearing housing to prevent discharge of drilling fluid (mud) from the bearing assembly into the wellbore annulus. The mechanical seal is effected by mating wear-resistant annular contact surfaces provided on the mandrel and the bearing housing, with biasing means preferably being provided to keep the contact surfaces in sealing engagement during both on-bottom and off-bottom operational modes. The diverted drilling fluid passing through the bearings is redirected into the bore of the mandrel via ports through the mandrel wall to rejoin the main flow to the drill bit, such that substantially all of the drilling fluid flows through the bit.

Abstract: In a mud-lubricated bearing assembly for a downhole motor, a mechanical seal is provided between the mandrel and the lower end of the bearing housing to prevent discharge of drilling fluid (mud) from the bearing assembly into the wellbore annulus. The mechanical seal is effected by mating wear-resistant annular contact surfaces provided on the mandrel and the bearing housing, with biasing means preferably being provided to keep the contact surfaces in sealing engagement during both on-bottom and off-bottom operational modes. The diverted drilling fluid passing through the bearings is redirected into the bore of the mandrel via ports through the mandrel wall to rejoin the main flow to the drill bit, such that substantially all of the drilling fluid flows through the bit.

Abstract: A mechanism for adjusting the relative angular orientation between two coaxial components includes a housing, a mandrel disposed in the housing, a lower ratchet member disposed around the mandrel, wherein a lower engagement interface between the lower ratchet member and the mandrel restricts relative rotation between the lower ratchet member and the mandrel, an upper ratchet member disposed around the mandrel, wherein an upper engagement interface between the upper ratchet member and the mandrel restricts relative rotation between the upper ratchet member and the mandrel, and a central sleeve disposed around the mandrel, wherein an outer engagement interface between the central sleeve and the housing restricts relative rotation between the central sleeve and the housing, wherein the central sleeve has an upper position configured to transmit torque between the upper ratchet member and the housing and a lower position configured to transfer torque between the lower ratchet member and housing.

Abstract: A mechanism for adjusting the relative angular orientation of two coaxial components includes a mandrel having a cylindrical central section between upper and lower splined sections, a sleeve rotatably and slidably disposed around the mandrel's central section, and generally cylindrical upper and lower ratchet members positioned, respectively, about the mandrel's upper and lower splined sections. The ratchet members have internal grooves which receive the mandrel splines for torsional load transfer while permitting limited rotation relative to the mandrel, but their axial positions relative to the mandrel are fixed. The upper and lower ends of the sleeve have circumferentially-arrayed ratchet teeth engageable, respectively, with corresponding teeth on the upper and lower ratchet members. The central sleeve has torque-transferring external splines slidable within matching grooves on the inner surface of a cylindrical tool housing enclosing the mechanism.

Abstract: A bearing assembly for a downhole motor comprises a housing having an upper end, a lower end, a radially inner surface, and a radially outer surface. In addition, the bearing assembly comprises a mandrel rotatably disposed within the housing. Further, the bearing assembly comprises an upper seal assembly, a lower seal assembly, and a thrust bearing assembly, each radially positioned between the housing and the mandrel. The bearing assembly also comprises a lubricating fluid radially disposed between the housing and the mandrel. The lower end of the housing comprises a first check valve radially positioned between the radially inner surface and the radially outer surface of the housing. The check valve is in fluid communication with the lubricating fluid and is adapted to allow at least a portion of the lubricant to exit the bearing assembly at a predetermined pressure differential.

Abstract: A steerable drilling apparatus includes a control system inside a cylindrical housing connected to a drill bit having radially-extendable pistons. A fluid-metering assembly directs a piston actuating fluid into fluid channels in the drill bit leading to respective pistons. The control system controls the fluid-metering assembly to selectively allow fluid flow through the fluid channels to the pistons and to exit through orifices in the fluid channels. The selective fluid flow causes the actuated piston to temporarily extend in the opposite direction to a desired wellbore deviation, thereby deflecting the drill bit away from the borehole centerline. An upper member in the fluid-metering assembly can be moved to stabilize, steer, and change TFA within the drill bit. The control system and drill bit are connected so as to facilitate removal to change the drill bit's steering section and cutting structure configuration or gauge simultaneously.

Abstract: A drive shaft assembly for a downhole motor includes a drive shaft formed with convexly spherical bearing surfaces on each end, and end housings with concavely spherical bearing surfaces for mating contact with the spherical bearing surfaces of the drive shaft, thereby facilitating omni-directional articulation between the drive shaft and the end housings while transferring axial thrust loads between the drive shaft and end housings across the interface of the mating spherical bearing surfaces. Torque is transferred between the drive shaft and end housings through two or alternatively four swivelling drive keys mounted to each end of the drive shaft and engageable with complementary drive key slots in the end housings. Full and constant torque-transferring contact is thus provided between the swivelling drive keys and the end housings irrespective of any angular offset between the drive shaft and the end housings, resulting from omni-directional articulation of the drive shaft relative to the end housing.

Abstract: A mechanism for adjusting the relative angular orientation of two coaxial components includes a mandrel having a cylindrical central section between upper and lower splined sections, a sleeve rotatably and slidably disposed around the mandrel's central section, and generally cylindrical upper and lower ratchet members positioned, respectively, about the mandrel's upper and lower splined sections. The ratchet members have internal grooves which receive the mandrel splines for torsional load transfer while permitting limited rotation relative to the mandrel, but their axial positions relative to the mandrel are fixed. The upper and lower ends of the sleeve have circumferentially-arrayed ratchet teeth engageable, respectively, with corresponding teeth on the upper and lower ratchet members. The central sleeve has torque-transferring external splines slidable within matching grooves on the inner surface of a cylindrical tool housing enclosing the mechanism.

Abstract: Apparatus and methods for increasing the torque capacity of connections between tubular members. In some embodiments, the connection is threaded. The apparatus may include a first tubular end having a torque member moveable thereon. A second tubular end is made up with the first tubular end. The torque member is moveable back toward the second tubular end. The torque member can be moved into engagement with the second tubular end, and then torqued against the second tubular end. A first torquing interface is provided between the first tubular and the second tubular by making up their respective ends, and a second torquing interface is provided therebetween by torquing the torque member against the second tubular end. A torque capacity of the made up connection is increased thereby.

Abstract: A downhole rotational rate control apparatus, adapted for coupling to the lower end of a drill string, includes a progressive cavity (PC) motor, a driveshaft, a mud flow control valve, and an electronics section. Drilling mud flowing downward through the drill string is partially diverted to flow upward through the PC motor and out into the wellbore annulus, with the mud flow rate and, in turn, the PC motor speed being controlled by the mud flow control valve. The control valve is actuated by a control motor in response to inputs from a sensor assembly in the electronics section. The PC motor drives the driveshaft and a controlled downhole device at a specific zero or non-zero rotational rate. By varying the rotational rate of the PC motor relative to the rotational rate of the drill string, the tool face orientation or non-zero rotational speed of the controlled device in either direction can be varied in a controlled manner.

Abstract: A bearing assembly for a downhole motor comprises a housing having an upper end, a lower end, a radially inner surface, and a radially outer surface. In addition, the bearing assembly comprises a mandrel rotatably disposed within the housing. Further, the bearing assembly comprises an upper seal assembly, a lower seal assembly, and a thrust bearing assembly, each radially positioned between the housing and the mandrel. The bearing assembly also comprises a lubricating fluid radially disposed between the housing and the mandrel. The lower end of the housing comprises a first check valve radially positioned between the radially inner surface and the radially outer surface of the housing. The check valve is in fluid communication with the lubricating fluid and is adapted to allow at least a portion of the lubricant to exit the bearing assembly at a predetermined pressure differential.

Abstract: A hydraulic jar for a drilling assembly is disclosed. In some embodiments, the hydraulic jar includes a tubular housing, a mandrel disposed in the housing, an annulus between the mandrel and the housing, and a pressure relief mechanism disposed in the annulus. The pressure relief mechanism generally divides the annulus into first and second portions. The pressure relief mechanism includes first and second annular members in engagement with one another when the pressure in the second annulus portion is less than a predetermined value and a fluid flow path between the first and second annulus portions. The fluid flow path has a first size when the pressure in the second annulus portion is less than the predetermined value, and a second size that is larger than the first size when the pressure in the second annulus portion becomes equal to or greater than the predetermined value.

Abstract: A drive shaft assembly for a downhole motor includes a drive shaft formed with convexly spherical bearing surfaces on each end, and end housings with concavely spherical bearing surfaces for mating contact with the spherical bearing surfaces of the drive shaft, thereby facilitating omni-directional articulation between the drive shaft and the end housings while transferring axial thrust loads between the drive shaft and end housings across the interface of the mating spherical bearing surfaces. Torque is transferred between the drive shaft and end housings through two or alternatively four swivelling drive keys mounted to each end of the drive shaft and engageable with complementary drive key slots in the end housings. Full and constant torque-transferring contact is thus provided between the swivelling drive keys and the end housings irrespective of any angular offset between the drive shaft and the end housings, resulting from omni-directional articulation of the drive shaft relative to the end housing.