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Dynamic Phase Difference Correction

IP.com Disclosure Number: IPCOM000240593D
Publication Date: 2015-Feb-10
Document File: 3 page(s) / 86K

Publishing Venue

The IP.com Prior Art Database

Abstract

One of the key measurements made during drilling and evaluation is resistivity. The Multiple Propagation Resistivity (MPR) node on the tracking tool provides real-time resistivity measurements during drilling. The MPR node consists of a single analog transmitter channel that fires four transmitter antennas and two receiver antennas with corresponding two receiver analog channels. Together, they provide compensated attenuation ratio and phase shift measurements which are used to compute attenuation resistivity and phase resistivity respectively. Analog filters on the transmitter and dual receiver channels are used to reject noise/interference signals that could potentially interfere with the resistivity measurement. The electronic components used in these filters have to be matched manually to within 0.5. If these components are not matched then the phase delays introduced by the filters in the transmitter and two receiver channels will cause significant error in the phase resistivity measurement. The process of matching these components, however, poses a challenge to the manufacturing process. In order to eliminate this requirement for matching the filter components, an algorithm along with an internally generated reference signal is used to dynamically calculate the phase error introduced by the mismatched components and an appropriate correction is applied to the measurement in real time. This procedure will be useful for correcting for electronic components drift with temperature.

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RES4-54389

Title:

Dynamic Phase Difference Correction

Abstract:

One of the key measurements made during drilling and evaluation is resistivity.  The Multiple Propagation Resistivity (MPR) node on the tracking tool provides real-time resistivity measurements during drilling.  The MPR node consists of a single analog transmitter channel that fires four transmitter antennas and two receiver antennas with corresponding two receiver analog channels.  Together, they provide compensated attenuation ratio and phase shift measurements which are used to compute attenuation resistivity and phase resistivity respectively.  Analog filters on the transmitter and dual receiver channels are used to reject noise/interference signals that could potentially interfere with the resistivity measurement.  The electronic components used in these filters have to be matched manually to within 0.5.  If these components are not matched then the phase delays introduced by the filters in the transmitter and two receiver channels will cause significant error in the phase resistivity measurement.  The process of matching these components, however, poses a challenge to the manufacturing process.  In order to eliminate this requirement for matching the filter components, an algorithm along with an internally generated reference signal is used to dynamically calculate the phase error introduced by the mismatched components and an appropriate correction is applied to the measurement in real time.  Thi...