Abstract: An information-carrying acoustic-pressure wave is generated in a wellbore using mud pulse telemetry. The information-carrying acoustic-pressure wave is converted, downhole, into an information-carrying electromagnetic wave and that wave is transmitted to the surface where it is received and the information extracted. A downhole repeater converts the acoustic-pressure wave and transmits the electromagnetic wave. The signal is received by an uphole/surface receiver. The repeater and/or the surface receiver may use an insulating gap. The electromagnetic signal is modeled as a leaky and noisy electronic circuit and the modeling results are used to select a spread spectrum transmission technique. The selected spread spectrum transmission technique is used to transmit the information-carrying electromagnetic signal at an increased rate of data transmission.

Abstract: A system and methods for drilling a well in a field having an previously drilled well are provided. In accordance with one example, a method includes drilling a new well in a geological formation having an previously drilled well using a bottom hole assembly (BHA) having a transmitter. The method also includes transmitting a signal while drilling using the transmitter of the BHA. Further, the method includes measuring from the previously drilled well the signal from the transmitter received by at least one optical fiber disposed within the previously drilled well.

Abstract: A method for drilling a well includes applying a current across a drill collar that surrounds an internal magnetometer. The current travels across the drill collar and along one or more other current paths to return to the drill collar. The method also includes using the magnetometer to measure magnetic fields due to the current being applied across the drill collar and the current across one or more other current paths while the drill collar is disposed at a first angle of rotation and rotating the drill collar to a second angle of rotation. The method further includes measuring the magnetic fields using the internal magnetometer while the drill collar is disposed at the second angle of rotation and determining a relationship between the current across the drill collar and a portion of the magnetic fields due to the current across the drill collar measurable by the internal magnetometer.

Abstract: A method and apparatus are provided for making directional measurements toward a formation of different resistivity that is proximate to the borehole, but which is not penetrated by the borehole. The methods and apparatus include the use of at least one insulated gap and at least one magnetometer positioned within a non-magnetic housing that is disposed within a non-magnetic tubular. An electric current is applied across the insulated gap, which results in current leaking into the surrounding formations. When a formation of contrasting resistivity is proximate to the logging apparatus, the magnetometer detects a secondary magnetic field due to the contrasting formation. The direction of the secondary magnetic field can be used to determine the direction to the contrasting formation. The magnitude of the secondary magnetic field can be used to determine the distance position to the contrasting formation.

Abstract: A downhole tool for subsurface disposal is provided. The tool comprises an elongated tool body, an enclosure attached to an exterior surface of the tool body. The enclosure comprises at least one transducer disposed at an angle with respect to a longitudinal axis of the enclosure, and an electronics board coupled to and disposed adjacent to the at least one transducer. The enclosure also defines an internal cavity, and the internal cavity contains a fluid for insulating the at least one transducer from a downhole environment. The fluid is in direct contact with the at least one transducer and the electronics board.

Abstract: A downhole tool for subsurface disposal is provided. The tool comprises an elongated tool body, an enclosure attached to an exterior surface of the tool body. The enclosure comprises at least one transducer disposed at an angle with respect to a longitudinal axis of the enclosure, and an electronics board coupled to and disposed adjacent to the at least one transducer. The enclosure also defines an internal cavity, and the internal cavity contains a fluid for insulating the at least one transducer from a downhole environment. The fluid is in direct contact with the at least one transducer and the electronics board.

Abstract: An enclosure for housing a transducer and electronics for disposal on a downhole tool. A transducer is disposed at an angle with respect to a longitudinal axis of the enclosure, wherein the enclosure contains a fluid surrounding the transducer. Enclosures also include transducers linked to motor means for selective rotation of the transducers within the enclosure. Enclosures with transducer arrays for phased or targeted signal transmission/detection.

Abstract: A method and apparatus are provided for making directional measurements toward a formation of different resistivity that is proximate to the borehole, but which is not penetrated by the borehole. The disclosed methods and apparatus include the use of at least one insulated gap and at least one magnetometer positioned within a non-magnetic housing that is disposed within a non-magnetic tubular. An electric current is applied across the insulated gap, which results in current leaking into the surrounding formations. When a formation of contrasting resistivity is proximate to the logging apparatus, the magnetometer detects a secondary magnetic due to the contrasting formation. The direction of the secondary magnetic field can be used to determine the direction to the contrasting formation. The magnitude of the secondary magnetic field can be used to determine the distance position to the contrasting formation.

Abstract: Systems and methods for improved acquisition of magnetic field data for magnetic ranging while drilling are provided. In one embodiment, such a system may include a borehole assembly and data processing circuitry. The borehole assembly may include an electric current driving tool configured to cause a current to flow across a drill collar of the borehole assembly and an internal magnetometer disposed within the drill collar and between the insulated gap and an end of the borehole assembly, which may be configured to measure magnetic field signals that penetrate the drill collar.

Abstract: A measurement package for disposal on an apparatus such as a downhole tool or a tool like device. The measurement package including an enclosure, a first acoustic transducer housed within the enclosure, a second acoustic transducer housed within the enclosure and electronics housed within the enclosure that is in communication with the first and second transducers. Further, an acoustic transmitter and receivers can be disposed at an angle with respect to a longitudinal axis of the enclosure. The enclosure can contain attenuative material surrounding the transmitter and receivers, and electronics for controlling the transmitter and receivers and communicating with the downhole tool.

Abstract: A measurement package for disposal on an apparatus such as a downhole tool or a tool like device. The measurement package including an enclosure, a first acoustic transducer housed within the enclosure, a second acoustic transducer housed within the enclosure and electronics housed within the enclosure that is in communication with the first and second transducers. Further, an acoustic transmitter and receivers can be disposed at an angle with respect to a longitudinal axis of the enclosure. The enclosure can contain attenuative material surrounding the transmitter and receivers, and electronics for controlling the transmitter and receivers and communicating with the downhole tool.

Abstract: A borehole caliper tool includes a tool body, a bow spring flexibly coupled to the tool body, a target coupled to the bow spring, and an ultrasonic transducer coupled to the tool body, wherein in operation the ultrasonic transducer transmits an acoustic pulse to the target and receives an echo of the acoustic pulse from the target.

Abstract: Methods for processing ultrasonic signal data to evaluate subsurface properties and tool orientation. Acoustic signals are transmitted into a plurality of azimuthal borehole positions. Formation echo signal transit time distributions are then determined in a plurality of azimuthal sectors for the acoustic signals. Front face echo signal transit times are also measured and farther-mode and closer-mode transit times are determined for the distribution of formation echo signals. Farther and closer tool standoffs are determined for the azimuthal sectors and a borehole diameter is determined from a summation including standoffs in opposing sectors. The standoffs are also used to determine a preferential tool position.

Abstract: Methods for processing ultrasonic signal data to evaluate subsurface properties and tool orientation. Acoustic signals are transmitted into a plurality of azimuthal borehole positions. Formation echo signal transit time distributions are then determined in a plurality of azimuthal sectors for the acoustic signals. Front face echo signal transit times are also measured and farther-mode and closer-mode transit times are determined for the distribution of formation echo signals. Farther and closer tool standoffs are determined for the azimuthal sectors and a borehole diameter is determined from a summation including standoffs in opposing sectors. The standoffs are also used to determine a preferential tool position.

Abstract: An ultrasonic sensor assembly for measuring the diameter of a well while it is being drilled is provided. The sensor assembly includes a stack including an inner sound absorbing backing element, a piezoelectric ceramic disk transducer stacked outwardly adjacent the backing element, and a matching layer, preferable made of PEEK and disposed outwardly adjacent the transducer. The layers of the stack are provided within a cavity of a metal cup and are maintained in position by a flexible diaphragm preferably made of PEEK. The diaphragm is sealed with an O-ring. A window, also preferably made of PEEK, is provided against the diaphragm and is held against the diaphragm by a spring. This arrangement acoustically couples the diaphragm to the stack and improves signal recovery. The diaphragm and O-ring form a hydraulic seal between fluid/mud in the well and the stack, and operate to retain the layers of the stack.