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Using the drill string to transfer the telemetry data is a focus in the fields of logging while drilling (LWD) and measurement while drilling (MWD). The acoustic property of the drill string is the foundation for improvement the transmission rate. In this paper, we study the filtering property of the drill string using the transfer matrix (TM) method.(More)
—Formation anisotropy evaluation is very important for complex reservoir in petroleum exploration. Cross-dipole array acoustic well logging technology breaks the restriction that shear waves could not be measured in soft formations. The cross-dipole acoustic data can be used to study the formation anisotropy. This paper presents an example of cross-dipole(More)
—A method of frequency inversion (FIM) is developed to analyze phase slowness of multi-channel dispersive waves. To verify this method, we processed both the synthesized multipole array waveforms excited by dipole source in fluid-filled borehole and field data measured by a multipole array acoustic logging tool (MPAL). The results show that FIM method is of(More)
Phased arc array transducers are key technologies of azimuthally acoustic logging tool. By controlling the high voltage fire signal phase of each unit of transmitters, radiation energy of phased arc array transducer can transmit to a single direction. Operational principle of phased arc array is analyzed, and experimental equipment used for physical(More)
Asymmetrical sources were introduced into modern well logging tools for measuring shear slowness of soft formation. However, the mode waves exciting in borehole are all dispersive waves. It is impossible to right extract the shear slowness using traditional slowness time coherence (STC) method. A new shear slowness extracting method is proposed based on(More)
A new method based on the predicting of phase difference (PPM) is developed to extract phase slowness from multi-channel dispersive waves. This method is verified by synthesized multipole array waveforms and field data measured by a multipole array acoustic logging tool (MPAL). The results show that this method is fast and stable for dispersion analysis.
The logging-while-drilling (LWD) systems mainly use the mud-pulse telemetry to transmit the measured data from the bottom to the surface. Its transmission rate, however, is very low, which is a severe limitation for the real-time transmission. Recently, using the drill string as the transmission carrier draws people's attentions and becomes one of the(More)
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