Class / Patent application number | Description | Number of patent applications / Date published |
340855300 | Multiplexed signals | 6 |
20090207041 | DOWNHOLE MEASUREMENT WHILE DRILLING SYSTEM AND METHOD - A method of measuring while drilling includes positioning at least one sensor downhole; and transmitting sensed data while drilling from the at least one sensor to surface without storing the sensed data downhole and system. | 08-20-2009 |
20090267790 | Changing Communication Priorities for Downhole LWD/MWD Applications - In one aspect of the present invention, a method for tool string communication comprising the steps of: providing a downhole tool string with at least two downhole LWD/MWD instruments in electrical communication with a downhole telemetry system, the instruments being capable of generating at least one data packet assigned a priority; then deploying the tool string in a well bore; and then changing the priority of the data packet. | 10-29-2009 |
20100039286 | Symbol Synchronization for Downhole OFDM Telemetry - Enhanced symbol synchronization methods suitable for use in narrowband orthogonal frequency division multiplexed (OFDM) telemetry systems. In at least some embodiments, a logging while drilling (LWD) tool assembly communicates with the surface using low frequency electromagnetic (EM) signals. The telemetry transmitter employs OFDM modulation to fully exploit the narrow range of available bandwidth, resulting in signals that have relatively long frames. At the surface a receiver digitizes the receive signal and applies an enhanced symbol synchronization technique to identify frame boundaries before demodulation is attempted. The enhanced symbol synchronization technique employs a pulse train filter to clean up a cyclic prefix correlation signal that otherwise behaves badly in the narrowband regime. The improved timing information from the enhanced symbol synchronization significantly reduces the error rate in the demodulated signal. | 02-18-2010 |
20100156662 | Subsea Electronic Module - An electronic module for use as a subsea electronic module for an underwater fluid extraction well, wherein a local area network enables communication within the module, the local area network including a plurality of interfaces with components of the network, and wherein the interfaces comprise capacitive coupling interfaces. | 06-24-2010 |
20140340235 | TIME DIVISION MULTIPLEXING (TDM) AND WAVELENGTH DIVISION MULTIPLEXING (WDM) FAST-SWEEP INTERROGATOR - Methods and apparatus for fast sweeping a spectral bandwidth in order to distinguish among signals received from effectively wavelength division multiplexed (WDMed) and time division multiplexed (TDMed) optical components on a single fiber. For some embodiments, a method for interrogating optical elements having characteristic wavelengths spanning a sweep range is provided. The method generally includes introducing a pulse of light, by an optical source, into an optical waveguide to interrogate at least a first set of optical elements having different characteristic wavelengths by performing a sweep of wavelengths over a period of the pulse, wherein the period is less than a round-trip time for light reflected from an optical element closest to the optical source to reach a receiver and processing the reflected light to determine a parameter based on the times at which signals are received. | 11-20-2014 |
20150029036 | SYSTEMS AND METHODS FOR GROUND FAULT IMMUNE DATA MEASUREMENT SYSTEMS FOR ELECTRONIC SUBMERSIBLE PUMPS - Provided are systems and methods for ground fault immune data measurement system for electric submersible pumps. A data measurement system coupled to the ESP includes a surface unit coupled to a 3-phase power cable for providing power to a 3-phase motor of the ESP and a downhole unit coupled to the motor of the ESP and located downhole in a well. The downhole unit includes sensor and is configured to generate frequency modulated carrier signals for carrying the sensor data to the surface unit. Each of the frequency modulated carrier signals carries identical sensor data and is modulated to a different frequency. The carrier signals are shunted across the motor windings of the ESP motor and onto the 3-phase power cable via a capacitive coupling. Additionally, another carrier signal carrying control data may be transmitted from the surface unit to the downhole unit. | 01-29-2015 |