| Patent application number | Description | Published |
|---|
| 20090205822 | Downhole Local Mud Weight Measurement Near Bit - A method for detecting a change in a wellbore fluid includes estimating at least two pressure differences in the wellbore fluid and estimating a change in a density of the fluid using the at least two pressure differences. The density change may be estimated by the equation, Δρ=(ΔP | 08-20-2009 |
| 20090322336 | Coherent In-Phase Demodulation for Resistivity Image Tools with Spread Spectrum Continuous Phase Modulation Stimulus - A method and system for measuring formation resisitivity is achieved by introducing one or more continuous phase modulated electrical signals into the formation, each signal introduced at a different location. The current of each introduced electrical signal is then sensed, producing an analog voltage signal as a measurement of the formation. Each introduced electrical signal is compared with its respective measured signal of the formation. Each comparison is made in a quadrature demodulation device, producing an in-phase demodulated signal. A quasi-direct-current signal is extracted from each in-phase demodulated signal, producing an analog measurement related to the resistivity of the formation. Each analog measurement is converted into a digital value for further processing. Successive measurements are digitally summed and averaged to increase the signal to noise ratio. | 12-31-2009 |
| 20090322337 | Analog Front-End Coherent In-Phase Demodulation Data Acquisition System for Resistivity Image Tools - A method and system for measuring formation resisitivity is achieved by introducing an electrical signal into the formation. The current of the introduced electrical signal is then sensed, producing an analog voltage signal as a measurement of the formation. The introduced electrical signal is compared with the measured signal of the formation. The comparison is made in a quadrature demodulation device, producing an in-phase demodulated signal. A quasi-direct-current signal is extracted from the in-phase demodulated signal, producing an analog measurement related to the resistivity of the formation. | 12-31-2009 |
| 20100118648 | EMAT Acoustic Signal Measurement Using Modulated Gaussian Wavelet and Hilbert Demodulation - Casing signals generated by an EMAT in a borehole are processed using one or more band-limited Gaussian filters. By using the Hilbert transform, an envelope of the filtered signals is determined and amplitudes and arrival times of individual arrivals are estimated. These can be used to estimate casing and cement properties. | 05-13-2010 |
| 20100118649 | Method and Apparatus for Echo-Peak Detection for Circumferential Borehole Image Logging - Signals from an acoustic transducer used in a borehole include overlapping, ringing reflections from the casing walls, voids in the cement and the formation. By using the Hilbert transform, an envelope of the signals is determined and individual echoes are detected by using a Gauss-Laplace operator. | 05-13-2010 |
| 20100169052 | Apparatus And Method For High Resolution Measurements For Downhole Tools - An apparatus and a method for reducing phase noise in measurement signals from a sensor are provided. The apparatus and method, in one aspect, may use a multiphase counter to obtain a count for each sensor signals time cycle and a filter to reduce noise from the obtained counts. A suitable reference frequency, including the reference frequency of the sensor, may be utilized by the multiphase counter. | 07-01-2010 |
| 20100265796 | Televiewer Image Wood-Grain Reduction Techniques - Measurements made by a transducer assembly for downhole imaging are affected by reverberations between the transducer and the window on the outside of the assembly. The reverberations result in a stationary noise on the image. Hardware solutions to improve signal-to-noise ratio includes using a composite transducer, adjusting the distance between the transducer and the window. SNR can also be improved by processing techniques that include stacking, fitting a sinusoid to the reverberation, by envelope peak detection, and by applying a notch filter. | 10-21-2010 |
| 20100295702 | High Speed Telemetry Full-Duplex Pre-Equalized OFDM Over Wireline for Downhole Communication - A Full-Duplex Pre-equalized OFDM system for high speed telemetry down-hole wire-line communication. The system compensates for the narrow bandwidth, high attenuation of, and noise in a downhole wireline using Trellis Code Modulation and Reed Solomon encoding. | 11-25-2010 |
| 20110022318 | High Resolution Sensor with Scalable Sample Rate - Apparatus and methods of providing a selected sample rate for sensor measurements are provided, which in one aspect may include a circuit configured to receive sensor signals as a first series of count rates corresponding to sensor the sensor measurements, each count rate representing a value of a parameter of interest, at least two accumulators configured to alternately accumulate the count rates in the series of count rates over a time period that corresponds to a selected sample rate and a controller configured to control the time periods for the at least two accumulators. | 01-27-2011 |
