Abstract: The invention provides drill bits and methods of drilling curved boreholes. One aspect of the invention provides a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths. Another aspect of the invention provides a method for drilling a curved borehole. The method includes: providing a drill string including a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths; rotating the drill string; and selectively actuating the one or more blades to a plurality of cut depths; thereby drilling a curved borehole.

Abstract: Apparatus and methods are described for highly attenuating vibrations of a drillstring assembly while drilling. In one embodiment, vibrations are attenuated by introducing one or more vibration attenuation modules at appropriate assembly locations. For example, vibration attenuation modules may be inserted at locations where vibration energy is expected to be maximal. In one embodiment the vibration attenuation modules include cavities loosely packed with particles of solid material such as sand or metallic powder. In one embodiment, the cavity walls are rough and/or include geometric features that enhance vibration energy transfer to the loosely packed particles in the cavity(ies). The vibration energy is dissipated via friction and inelastic particle-particle and particle-wall collisions that occur as a result of drillstring motion.

Abstract: Hydrostatic bearings are used for drill string stabilization and bottom hole assembly steering. The hydrostatic bearings utilize an existing mud flow as the bearing fluid. For steering, the bearings may be used between movable kick pads and the formation to reduce friction. Alternatively, differential hydrostatic bearing pressure may be utilized to steer. Multi-modal (non-linear and linear) steering may be provided by selectively applying equal and unequal hydrostatic bearing pressures. The bearings can be made more tolerant of imperfections in the formation by utilizing multiple pressure pockets.

Abstract: Apparatus and methods are described for highly attenuating vibrations of a drillstring assembly while drilling. In one embodiment, vibrations are attenuated by introducing one or more vibration attenuation modules at appropriate assembly locations. For example, vibration attenuation modules may be inserted at locations where vibration energy is expected to be maximal. In one embodiment the vibration attenuation modules include cavities loosely packed with particles of solid material such as sand or metallic powder. In one embodiment, the cavity walls are rough and/or include geometric features that enhance vibration energy transfer to the loosely packed particles in the cavity(ies). The vibration energy is dissipated via friction and inelastic particle-particle and particle-wall collisions that occur as a result of drillstring motion.

Abstract: Apparatus and methods are described for highly attenuating vibrations of a drillstring assembly while drilling. In one embodiment, vibrations are attenuated by introducing one or more vibration attenuation modules at appropriate assembly locations. For example, vibration attenuation modules may be inserted at locations where vibration energy is expected to be maximal. In one embodiment the vibration attenuation modules include cavities loosely packed with particles of solid material such as sand or metallic powder. In one embodiment, the cavity walls are rough and/or include geometric features that enhance vibration energy transfer to the loosely packed particles in the cavity(ies). The vibration energy is dissipated via friction and inelastic particle-particle and particle-wall collisions that occur as a result of drillstring motion.

Abstract: This invention provides rotating electrical connections and methods of using the same. One aspect of the invention provides a rotating electrical connection. The rotating electrical connection includes: a rotary member and a pin. The rotary member includes a contact surface and is configured for rotation about a rotational axis. The rotational axis intersects with the contact surface. The pin is configured to contact the rotary member at the intersection of the rotational axis and the contact surface.

Abstract: Steerable drilling systems for facilitating drilling according to a prescribed, three-dimensional trajectory are described. Steering may be achieved using passive actuators which require little or no power. For example, damping elements which couple a drill bit to a drill collar can be used to tilt the drill bit with respect to the drill collar. Alternatively, rotary cutting elements disposed on the drill bit may be used to control the force between the drill bit and the formation at different axial locations. The passive elements used to control the tilt or rotation of the rotary cutting elements are actuated in a certain pattern, e.g., geostationary, in order to achieve a desired deviation of the well bore while drilling ahead. One way to achieve this is through the use of field-sensitive materials, e.g. magnetorheological (MR) fluids, that change viscosity in response to an applied magnetic field.

Abstract: Electrical energy is produced by harvesting mechanical energy in the form of vibrations which are generally present in tools during the process of drilling oil wells. Electrical energy production is based on the Faraday induction principle whereby changes, i.e., movement, in magnetic flux through a coil induce an electric current through the coil. The changes in magnetic flux are produced by relative motion between at least one set of magnets and at least one coil. In particular, as the flux lines change due to the movement of the magnets, they remain perpendicular to both the direction of motion of the magnets as well as a planar or cylindrical surface defined by the coils. As a result, output for a given size of device is enhanced. Further, flexibility in adapting device form factor to particular shapes is enhanced. For example, a relatively flat device may be implemented using flexural bearing support of the magnets and coils on a printed circuit.

Abstract: A downhole drilling tool includes a housing defining an axial passageway and a shaft mounted for rotation within the axial passageway such that the housing and shaft form an annular gap. An electrical connector provides a signal to the shaft. The electrical connector includes a first lead assembly coupled to the housing and the shaft, and a second lead assembly coupled to the housing and the shaft. Each lead assembly has an outer ring electrode fixed to the housing and an inner ring electrode fixed to the shaft for rotation therewith such that connector gaps are formed between the outer ring electrodes and the inner ring electrodes. Drilling fluid is pumped through the annular gap to flow through the connector gaps to complete electrical connections between the outer ring electrodes and inner ring electrodes.

Abstract: A method and system is provided for determining the value of an attribute of ambient energy at a drilling assembly at the bottom of a borehole. Ambient energy includes kinetic energy, hydraulic energy and thermal energy. Attributes include vibration frequency spectrum, pressure difference, and temperature difference. The method uses energy harvested by at least one energy-harvesting sensor to power the system. The system generates data signals from at least one energy-harvesting sensor at one or more locations along a downhole drilling assembly, and transmits data up the borehole.

Abstract: This invention provides rotating electrical connections and methods of using the same. One aspect of the invention provides a rotating electrical connection. The rotating electrical connection includes: a rotary member and a pin. The rotary member includes a contact surface and is configured for rotation about a rotational axis. The rotational axis intersects with the contact surface. The pin is configured to contact the rotary member at the intersection of the rotational axis and the contact surface.

Abstract: A compact surface self-compensated hydrostatic bearing includes a rotor assembly including a rotor plate having upper and lower fluid restricting faces, a rotor top and bottom, each having bearing surfaces angled with respect to an axis of rotation of the rotor assembly; a stator assembly including a stator top and a stator bottom housing the rotor assembly therebetween, the stator top and bottom having bearing surfaces facing and spaced apart from the rotor top and bottom bearing surfaces forming upper and lower bearing gaps, respectively, therebetween; the stator top and bottom including a lower and an upper fluid restricting surface, respectively, facing and spaced apart from the rotor upper and rotor lower fluid restricting faces, respectively, forming upper and lower restricting gaps, respectively, therebetween; and a fluid supply system configured to supply pressurized fluid to the bearing gaps and into the upper and lower fluid restricting gaps.

Abstract: Steerable drilling systems for facilitating drilling according to a prescribed, three-dimensional trajectory are described. Steering may be achieved using passive actuators which require little or no power. For example, damping elements which couple a drill bit to a drill collar can be used to tilt the drill bit with respect to the drill collar. Alternatively, rotary cutting elements disposed on the drill bit may be used to control the force between the drill bit and the formation at different axial locations. The passive elements used to control the tilt or rotation of the rotary cutting elements are actuated in a certain pattern, e.g., geostationary, in order to achieve a desired deviation of the well bore while drilling ahead. One way to achieve this is through the use of field-sensitive materials, e.g. magnetorheological (MR) fluids, that change viscosity in response to an applied magnetic field.

Abstract: A drilling apparatus controls or eliminates reaction torque from drill bits thereby preventing loss of penetration due to undesired rotation of the drilling apparatus or controls drilling direction by intentionally manipulating reaction torque thereby inducing desired drill bit walk. The drilling apparatus has a concentrically divided drill bit in which an inner drill bit rotates simultaneously in the opposite direction from an outer drill bit. The inner drill bit can be moved axially forward from or back toward the outer drill bit. Forces produced by the inner and outer drill bits are controlled to eliminate or adjust reaction torque.

Abstract: A drilling apparatus controls or eliminates reaction torque from drill bits thereby preventing loss of penetration due to undesired rotation of the drilling apparatus or controls drilling direction by intentionally manipulating reaction torque thereby inducing desired drill bit walk. The drilling apparatus has a concentrically divided drill bit in which an inner drill bit rotates simultaneously in the opposite direction from an outer drill bit. The inner drill bit can be moved axially forward from or back toward the outer drill bit. Forces produced by the inner and outer drill bits are controlled to eliminate or adjust reaction torque.

Abstract: Hydrostatic bearings are used for drill string stabilization and bottom hole assembly steering. The hydrostatic bearings utilize an existing mud flow as the bearing fluid. For steering, the bearings may be used between movable kick pads and the formation to reduce friction. Alternatively, differential hydrostatic bearing pressure may be utilized to steer. Multi-modal (non-linear and linear) steering may be provided by selectively applying equal and unequal hydrostatic bearing pressures. The bearings can be made more tolerant of imperfections in the formation by utilizing multiple pressure pockets.

Abstract: Apparatus and methods are described for highly attenuating vibrations of a drillstring assembly while drilling. In one embodiment, vibrations are attenuated by introducing one or more vibration attenuation modules at appropriate assembly locations. For example, vibration attenuation modules may be inserted at locations where vibration energy is expected to be maximal. In one embodiment the vibration attenuation modules include cavities loosely packed with particles of solid material such as sand or metallic powder. In one embodiment, the cavity walls are rough and/or include geometric features that enhance vibration energy transfer to the loosely packed particles in the cavity(ies). The vibration energy is dissipated via friction and inelastic particle-particle and particle-wall collisions that occur as a result of drillstring motion.

Abstract: A method and system is provided for determining the value of an attribute of ambient energy at a drilling assembly at the bottom of a borehole. Ambient energy includes kinetic energy, hydraulic energy and thermal energy. Attributes include vibration frequency spectrum, pressure difference, and temperature difference. The method uses energy harvested by at least one energy-harvesting sensor to power the system. The system generates data signals from at least one energy-harvesting sensor at one or more locations along a downhole drilling assembly, and transmits data up the borehole.

Abstract: A compact surface self-compensated hydrostatic bearing includes a rotor assembly including a rotor plate having upper and lower fluid restricting faces, a rotor top and bottom, each having bearing surfaces angled with respect to an axis of rotation of the rotor assembly; a stator assembly including a stator top and a stator bottom housing the rotor assembly therebetween, the stator top and bottom having bearing surfaces facing and spaced apart from the rotor top and bottom bearing surfaces forming upper and lower bearing gaps, respectively, therebetween; the stator top and bottom including a lower and an upper fluid restricting surface, respectively, facing and spaced apart from the rotor upper and rotor lower fluid restricting faces, respectively, forming upper and lower restricting gaps, respectively, therebetween; and a fluid supply system configured to supply pressurized fluid to the bearing gaps and into the upper and lower fluid restricting gaps.

Abstract: An instrument for enabling a precise determination of the force-displacement characteristics of a compliant structure, including both in-plane and out-of-plane structure deflection, is provided by the invention. The instrument includes a fixture that is oriented for constraining an end of the compliant structure with respect to mechanical ground as the force-displacement characteristic is determined. A mechanical probe of the instrument is disposed relative to the fixture to enable pushing of the probe against a free end of the compliant structure. A mechanical stage is provided, including a support for the probe, and being free with respect to mechanical ground to advance the probe relative to the fixture. This enables pushing of the probe against the free end of the compliant structure.