Abstract: A downhole tool includes a downlinking system deployed in a downhole tool body having an internal through bore. The downlinking system includes a differential pressure transducer configured to measured a pressure difference between drilling fluid in the internal through bore and drilling fluid external to the tool (in the borehole annulus). The differential transducer is electrically connected with an electronic controller (deployed substantially anywhere in the drill string) that is configured to receive and decode pressure waveforms.

Abstract: A method for removing cyclic noise from a borehole image includes transforming the image into the frequency domain using a two-dimensional (2-D) transform (e.g., using a discrete cosine transform). The cyclic noise components (peaks) are removed from the transformed image which is then inverse transformed back into the spatial domain using an inverse 2-D transform to obtain a corrected image. An automated method enables the cyclic peaks to be identified and removed from the borehole image via downhole processing.

Abstract: A downlinking signal is transmitted downhole from the surface using drilling fluid as the communications medium. The downlinking signal includes at least a synchronization phase and a command phase. Attributes of the synchronization phase are used upon reception of the signal to determine corresponding attributes of the command phase. Commands may be transmitted downhole while drilling and simultaneously while using mud-pulse telemetry uplinking techniques.

Abstract: A method for managing a drilling operation, including generating, by a first sensor and a second sensor of a bottom hole assembly (BHA), a first time based data log and a second time based data log, respectively, representing a borehole parameter along a drilling trajectory, determining, by a computer processor of the BHA and during the drilling operation, a time shift by comparing the first time based data log and the second time based data log, where offsetting the first and second time based data logs by the time shift maximizes a correlation factor of the first and second time based data logs, and determining, within a pre-determined time period from generating the first and second time based data logs, a drilling speed based on the time shift and a pre-determined distance between the first sensor and the second sensor.

Abstract: Closed loop methods for drilling twin wells are disclosed. The disclosed method make use of a bottom hole assembly including a rotary steerable tool. An electrical current is induced in the target well. The corresponding magnetic field about the target well is measured in the twin well and used to guide drilling of the twin well.

Abstract: A downlinking signal is transmitted downhole from the surface using drilling fluid as the communications medium. The downlinking signal includes at least a synchronization phase and a command phase. Attributes of the synchronization phase are used upon reception of the signal to determine corresponding attributes of the command phase. Commands may be transmitted downhole while drilling and simultaneously while using mud-pulse telemetry uplinking techniques.

Abstract: A method for making downhole whirl measurements in a drill string includes rotating a sensor set in a borehole. The sensor set is deployed in the drill string and includes at least one cross-axial accelerometer and at least one cross-axial magnetometer. Sensor measurements, including a plurality of accelerometer measurements and a plurality of magnetometer measurements made at predetermined measurement intervals, may be obtained while drilling and used to compute a whirl magnitude.

Abstract: Aspects of this invention include a downhole tool having an angular position sensor disposed to measure the relative angular position between first and second members disposed to rotate about a common axis. A plurality of magnetic field sensors are deployed about the second member and disposed to measure magnetic flux emanating from first and second magnets deployed on the first member. A controller is programmed to determine the relative angular position based on magnetic measurements made by the magnetic field sensors. In a one exemplary embodiment, a downhole steering tool includes first and second magnets circumferentially spaced on the shaft and a plurality of magnetic field sensors deployed about the housing.

Abstract: A method for making downhole dynamics measurements using rotating navigational sensors includes rotating navigational accelerometers in a subterranean borehole to obtain a string of accelerometer measurements while rotating. The measurements are differentiated to obtain a string of differentiated accelerometer measurements and may then be further processed to obtain a drill string vibration parameter. Substantially simultaneous magnetometer measurements may be obtained and utilized to compute a corrected vibration parameter in which at least one of a gravitational acceleration component, a tangential acceleration component, and a centripetal acceleration component is removed from the vibration parameter.

Abstract: A downhole tool includes a downlinking system deployed in a downhole tool body having an internal through bore. The downlinking system includes a differential pressure transducer configured to measured a pressure difference between drilling fluid in the internal through bore and drilling fluid external to the tool (in the borehole annulus). The differential transducer is electrically connected with an electronic controller (deployed substantially anywhere in the drill string) that is configured to receive and decode pressure waveforms.

Abstract: Aspects of this invention include a downhole assembly having a non-contact, capacitive coupling including first and second transceivers deployed in corresponding first and second downhole tool members. The capacitive coupling is disposed to transfer electrical signals between the first and second transceivers. In one exemplary embodiment, the capacitive coupling is configured to transfer data and power between a substantially non-rotating tool member and a rotating tool member, for example, the shaft and blade housing in a steering tool. Exemplary embodiments of this invention provide a non-contact, high-speed data communication channel between first and second members of a downhole assembly. Moreover, exemplary embodiments of the invention also provide for simultaneous non-contact transmission of electrical power between the first and second tool members.

Abstract: A steering tool has a controller configured to provide closed-loop control of blade pressure and position. In one embodiment, the controller is configured to execute a directional control methodology in which the drilling direction is controlled via control of the blade position. The pressure in each blade is further controlled within a predetermined range of pressures. This embodiment tends to prevent excessive borehole friction while at the same time reducing undesirable rotation of the blade housing. In another embodiment, the controller is configured to correlate blade pressure measurements and blade position measurements during drilling. The correlation is utilized as part of a secondary directional control scheme in the event of a downhole failure of a blade position and/or pressure sensor.

Abstract: Aspects of this invention include a downhole assembly having a non-contact, capacitive coupling including first and second transceivers deployed in corresponding first and second downhole tool members. The capacitive coupling is disposed to transfer electrical signals between the first and second transceivers. In one exemplary embodiment, the capacitive coupling is configured to transfer data and power between a substantially non-rotating tool member and a rotating tool member, for example, the shaft and blade housing in a steering tool. Exemplary embodiments of this invention provide a non-contact, high-speed data communication channel between first and second members of a downhole assembly. Moreover, exemplary embodiments of the invention also provide for simultaneous non-contact transmission of electrical power between the first and second tool members.

Abstract: A downlinking signal is transmitted downhole from the surface using drilling fluid as the communications medium. The downlinking signal includes at least a synchronization phase and a command phase. The downlinking signal is differentiated upon reception such that attributes of the synchronization phase may be used to determine corresponding attributes of the command phase. Commands may be transmitted downhole while drilling and simultaneously while using mud-pulse telemetry uplinking techniques.

Abstract: A downlinking signal is transmitted downhole from the surface using drilling fluid as the communications medium. The downlinking signal includes at least a synchronization phase and a command phase. Attributes of the synchronization phase are used upon reception of the signal to determine corresponding attributes of the command phase. Commands may be transmitted downhole while drilling and simultaneously while using mud-pulse telemetry uplinking techniques.

Abstract: Aspects of this invention include a downhole tool and method for making a physical caliper measurement of a subterranean borehole. The tool is configured to make the physical borehole caliper measurement only when the measured pressure in each of three or more outwardly extendable blades is greater than a predetermined threshold pressure. Blade positions are measured and the borehole caliper calculated only when the pressure in each of the blades exceeds the threshold. Exemplary embodiments of the invention enable physical caliper measurements to be made with increased accuracy with each of the blades making firm contact with the borehole wall. Methods in accordance with the invention are especially well suited for use in directional drilling applications in that they tend to enable accurate caliper measurements to be made without repositioning the steering tool in the borehole.

Abstract: A steering tool configured for making azimuthal and non-azimuthal formation evaluation measurements is disclosed. In one embodiment a rotary steerable tool includes at least one formation evaluation sensor deployed in the steering tool housing. The steering tool may include, for example, first and second circumferentially opposed formation evaluation sensors or first, second, and third formation evaluation sensors, each of which is radially offset and circumferentially aligned with a corresponding one of the steering tool blades. The invention further includes methods for geosteering in which a rotation rate of the steering tool housing in the borehole (and therefore the rotation rate of the formation evaluation sensors) is controlled. Steering decisions may be made utilizing the formation evaluation measurements and/or derived borehole images.

Abstract: A method for removing cyclic noise from a borehole image includes transforming the image into the frequency domain using a two-dimensional (2-D) transform (e.g., using a discrete cosine transform). The cyclic noise components (peaks) are removed from the transformed image which is then inverse transformed back into the spatial domain using an inverse 2-D transform to obtain a corrected image. An automated method enables the cyclic peaks to be identified and removed from the borehole image via downhole processing.

Abstract: A steering tool configured for making azimuthal and non-azimuthal formation evaluation measurements is disclosed. In one embodiment a rotary steerable tool includes at least one formation evaluation sensor deployed in the steering tool housing. The steering tool may include, for example, first and second circumferentially opposed formation evaluation sensors or first, second, and third formation evaluation sensors, each of which is radially offset and circumferentially aligned with a corresponding one of the steering tool blades. The invention further includes methods for geosteering in which a rotation rate of the steering tool housing in the borehole (and therefore the rotation rate of the formation evaluation sensors) is controlled. Steering decisions may be made utilizing the formation evaluation measurements and/or derived borehole images.

Abstract: Aspects of this invention include methods for surveying a subterranean borehole. In one exemplary aspect, a change in borehole azimuth between first and second longitudinally spaced gravity measurement sensors may be determined directly from gravity measurements made by the sensors and a measured angular position between the sensors. The gravity measurement sensors are typically disposed to rotate freely with respect to one another about a longitudinal axis of the borehole. Gravity MWD measurements in accordance with the present invention may be advantageously made without imposing any relative rotational constraints on first and second gravity sensor sets. The present invention also advantageously provides for downhole processing of the change in azimuth between the first and second gravity sensor sets. As such, Gravity MWD measurements in accordance with this invention may be advantageously utilized in closed-loop steering control methods.