Abstract: This invention is directed to a downhole method and apparatus for simultaneously determining the horizontal resistivity, vertical resistivity, and relative dip angle for anisotropic earth formations. The present invention accomplishes this objective by using an antenna configuration in which a transmitter antenna and a receiver antenna are oriented in non-parallel planes such that the vertical resistivity and the relative dip angle are decoupled. Preferably, either the transmitter or the receiver is mounted in a conventional orientation in a first plane that is normal to the tool axis, and the other antenna is mounted in a second plane that is not parallel to the first plane. Although this invention is primarily intended for MWD or LWD applications, this invention is also applicable to wireline and possibly other applications.

Abstract: Oil-based mud imaging systems and methods that measure formation permittivity. In some embodiments, disclosed logging systems include a logging tool in communication with surface computing facilities. The logging tool is provided with a sensor array having at least two voltage electrodes positioned between at least two current electrodes that create an electric field in a borehole wall, and is further provided with electronics coupled to the voltage electrodes to determine a differential voltage magnitude and phase. From the magnitude and phase, formation resistivity and permittivity measurements can be determined and used to construct a borehole wall image.

Abstract: In some embodiments, a system comprises a system memory module and an access card. The system memory module connects to a memory bus on a motherboard for a personal computer, while the access card connects to an expansion bus. The access card couples to the system memory module to provide power when the personal computer is unpowered. When the personal computer boots, the system memory module operates in a cloaked mode that hides the system memory module from a memory bus. The access card switches the system memory module from the cloaked mode to a normal mode in response to a command received via the expansion bus. For long-term power outages, the access card may copy data from the system memory module to a nonvolatile information storage device. Energy storage and nonvolatile information storage may be provided by a separate longevity unit that couples to the access card.

Abstract: A system for communicating information in a borehole between tool assemblies in a tool string includes receiving an information signal and separating a first signal that may be a power and low speed signal. A second signal is separated and demodulated from the information signal. The first signal and second signal are transmit to electronic devices that process data from an earth formation. After the first and second signals are transmit to one or more electronic devices, the signals are modulated and/or filtered and then combined into the information signal. The first signal is at one frequency and the second signal is at a different frequency. The apparatus includes a main signal line that couples to a second signal line and third signal line in the tool assembly.

Abstract: An apparatus and method for minimizing the effects of a common mode voltage signal in downhole logging tools utilized to determine the resistivity of an adjacent portion of a borehole wall. Two current electrodes are energized by an excitation source to create an oscillatory electric field in a borehole wall. A voltage drop across a segment of the borehole wall is measured by two voltage electrodes, and the differential voltage is used in combination with a measured current flow to determine a resistivity value for the borehole wall. A common mode voltage in front of the two voltage electrodes is measured and minimized by controlling the excitation source, thereby reducing the resistivity measurement error.

Abstract: A method and apparatus for generating an acoustic signal having a single mode of propagation along borehole walls. The method includes generating an n-pole (monopole, dipole, quadrupole, and so on) acoustic signal and calculating the tool position and borehole shape from the signals received at one or more receivers. If the tool contains matched sources and balanced receivers, is in the center of the borehole, and the borehole is circular, the pure, single mode acoustic signal will propagate along the borehole walls with a single mode of propagation. If the acoustic signal traveling along borehole walls does not have a single mode of propagation, the signal's amplitudes and time delays are adjusted to produce a second acoustic signal. The second acoustic signal's amplitudes and time delays are further adjusted until the signal traveling along the borehole walls has a single mode of propagation.

Abstract: Systems and methods for performing bed boundary detection and azimuthal resistivity logging with a single tool are disclosed. Some method embodiments include logging a borehole with an azimuthally-sensitive resistivity logging tool; deriving both a resistivity log and a boundary detection signal from measurements provided by said tool; and displaying at least one of the boundary detection signal and the resistivity log. The resistivity log measurements may be compensated logs, i.e., logs derived from measurements by one or more symmetric transmitter-receiver arrangements. Though symmetric arrangements can also serve as the basis for the boundary detection signal, a greater depth of investigation can be obtained with an asymmetric arrangement. Hence the boundary detection signal may be uncompensated.

Abstract: This invention is directed to a downhole method and apparatus for simultaneously determining the horizontal resistivity, vertical resistivity, and relative dip angle for anisotropic earth formations. The present invention accomplishes this objective by using an antenna configuration in which a transmitter antenna and a receiver antenna are oriented in non-parallel planes such that the vertical resistivity and the relative dip angle are decoupled. Preferably, either the transmitter or the receiver is mounted in a conventional orientation in a first plane that is normal to the tool axis, and the other antenna is mounted in a second plane that is not parallel to the first plane. Although this invention is primarily intended for MWD or LWD applications, this invention is also applicable to wireline and possibly other applications.

Abstract: This invention is directed to a downhole method and apparatus for simultaneously determining the horizontal resistivity, vertical resistivity, and relative dip angle for anisotropic earth formations. The present invention accomplishes this objective by using an antenna configuration in which a transmitter antenna and a receiver antenna are oriented in non-parallel planes such that the vertical resistivity and the relative dip angle are decoupled. Preferably, either the transmitter or the receiver is mounted in a conventional orientation in a first plane that is normal to the tool axis, and the other antenna is mounted in a second plane that is not parallel to the first plane. This invention also relates to a method and apparatus for steering a downhole tool during a drilling operation in order to maintain the borehole within a desired earth formation.

Abstract: Improved communication systems and methods are disclosed. In one embodiment, a downhole communications system comprises a downhole transceiver and a surface transceiver. The surface transceiver receives a discrete multi-tone (DMT) modulated uplink signal from the downhole transceiver, and transmits a downlink signal to the downhole transceiver using a modulation method determined by the transceivers as communications are initiated. The downlink modulation methods supported by the surface transceiver may include DMT modulation and quadrature amplitude modulation (QAM). The modulation mode selection may be based on measured channel characteristics, on proposed data rates, or on other predetermined parameters. The uplink and downlink signals may be communicated over a shared transmission mode on multiconductor cable or wired pipe, and alternatively the uplink and downlink signals may be communicated over separate transmission modes.

Abstract: High temperature imaging devices are disclosed. In one embodiment, the imaging device comprises an array of photosensitive elements fabricated on an insulator substrate, and an information storage component coupled to the array. The information storage component stores data representing one or more light patterns detected by the array. The light patterns may be images or spectral patterns. The insulator substrate may be a sapphire or spinel substrate. Alternatively, the substrate may be silicon carbide or an insulated silicon substrate. In at least some embodiments, a processor is integrated on the same substrate as the array.

Abstract: A method and apparatus is presented for performing a sequence-level CRC calculation on fiber channel communications within a switching platform domain. A CRC generator searches the data communication for frames that contain the type of data for which a sequence-level CRC is desired, such as for a sequence containing SCSI data. If found, and the type of data allows multiple frames per sequence, the present invention creates a CRC value for the sequence. An intermediate CRC value is stored in a queue to allow the simultaneous calculation of sequence level CRC values for multiple frames. With inbound data, the sequence-level CRC is appended to the end of the sequence data. With outbound data, the calculated value is compared with the appended, expected value, With single-frame fiber channel protocols, the frame-level CRC value is obtained directly from the frames entering the switching platform domain.

Abstract: Acoustic telemetry systems and methods with surface noise cancellation. One illustrative embodiment may include an acoustic telemetry system comprising a transmitter configured to generate an acoustic information signal that propagates along a drillstring, and a receiver configured to detect an acoustic receive signal from the drillstring and a noise signal from a surface environment. The receiver operates on the acoustic receive signal and the noise signal to produce a modified signal indicative of the acoustic information signal and having a reduced noise content relative to the acoustic receive signal.

Abstract: In at least some embodiments, electronic devices suitable for use at temperatures in excess of 200 C. may comprise an integrated circuit fabricated on a silicon carbide substrate, and a thick passivation layer. In other embodiments, electronic devices suitable for use at temperatures in excess of 200 C. may comprise an integrated circuit formed from silicon located on a sapphire substrate, and a thick passivation layer. The electronic devices may be implemented in the context of hydrocarbon drilling and production operations.

Abstract: A system and method for generating a neural network ensemble. Conventional algorithms are used to train a number of neural networks having error diversity, for example by having a different number of hidden nodes in each network. A genetic algorithm having a multi-objective fitness function is used to select one or more ensembles. The fitness function includes a negative error correlation objective to insure diversity among the ensemble members. A genetic algorithm may be used to select weighting factors for the multi-objective function. In one application, a trained model may be used to produce synthetic open hole logs in response to inputs of cased hole log data.

Abstract: A method and related system for correcting measurements obtained from an induction logging device. In one embodiment, the method comprises: receiving conductivity measurements from a multi-array induction tool; constructing a measurement pattern vector from the conductivity measurements; determining one or more geometry parameters associated with an approximation of the measurement pattern vector; finding borehole geometrical factors using current values of the one or more conductivity parameters and of the one or more geometry parameters; and calculating improved estimates of the one or more conductivity parameters using current values of the borehole geometric factors. The geometry parameters may be determined by finding a geometry pattern vector that best fits the measurement pattern vector. The determining, finding, and calculating operations may be repeated until a predetermined condition is satisfied.

Abstract: This invention is directed to a downhole method and apparatus for simultaneously determining the horizontal resistivity, vertical resistivity, and relative dip angle for anisotropic earth formations. The present invention accomplishes this objective by using an antenna configuration in which a transmitter antenna and a receiver antenna are oriented in non-parallel planes such that the vertical resistivity and the relative dip angle are decoupled. Preferably, either the transmitter or the receiver is mounted in a conventional orientation in a first plane that is normal to the tool axis, and the other antenna is mounted in a second plane that is not parallel to the first plane. This invention also relates to a method and apparatus for steering a downhole tool during a drilling operation in order to maintain the borehole within a desired earth formation.

Abstract: Methods and systems employing combined source-channel coding for multi-carrier modulation (MCM). In some embodiments, a described method comprises: estimating channel gain to noise ratio (CGNR) as a function of frequency bin; determining MCM parameters that minimize distortion of one or more telemetry signals; generating a communications signal using the MCM parameters, and transmitting the communications signal via a communications channel. The MCM parameters may be determined by minimizing a telemetry signal distortion measure subject to CGNR and a transmit power constraint. The MCM parameters may further account for differing fidelity requirements when multiple telemetry signals are being transmitted.

Abstract: Various embodiments of an electrical motor, a brushless DC motor controller, and applications thereof. In one embodiment, a fluid-moving device is provided with a brushless DC motor and a motor controller. The controller may include a set of comparators and a clocked digital circuit. The set of comparators are each configured to determine a voltage polarity on a respective winding of a stator. The clocked digital circuit is configured to receive polarity signals from the comparators and configured to detect in the polarity signals zero crossings having an expected crossing direction. The clocked digital circuit is also configured to determine a commutational sequence for energizing windings on the stator. Other embodiments may include a disk drive, an implantable medical device, a vehicle, and a downhole tool.