Halliburton Energy Services, Inc.

Gowell International, LLC

Jiajun Zhao

Ruijia Wang

Chung Lung Chang

Jing Jin

Richard Timothy Coates

Jinsong Zhao

Wei-Bin Ewe

Qinshan Yang

Qingtao Sun

Jonathan Brenda Sue

An acoustic transducer includes a substrate element having a first side, and a second side opposite the first side. The acoustic transducer also includes first and second piezoelectric elements coupled to the first side, and third and fourth piezoelectric elements coupled to the second side. The first piezoelectric element has a first polarity, and the second piezoelectric element has a second polarity different than the first polarity. The third piezoelectric element has a third polarity, and the fourth piezoelectric element has a fourth polarity different than the third polarity.

Acoustic transducer with piezoelectric elements having different polarities

Methods to estimate formation slowness from multi-borehole modes and multi-mode dispersion estimation systems are presented. The method includes obtaining waveform data of a plurality of waves traversing through a downhole formation, wherein each wave of the plurality of waves has a different threshold cutoff frequency, and performing a multimode dispersion analysis of the waveform data to generate a semblance map of the wave comprising the plurality of waves. The method also includes obtaining a slowness dispersion of a wave of the plurality of waves, and determining a formation type of the wave based on one or more properties of the plurality of waves. The method further includes determining an initial body wave slowness estimate of the wave, generating a modeling of the wave, and reducing a mismatch between the modeling of the wave and the slowness dispersion of the wave to improve the modeling of the wave.

Methods to estimate formation slowness from multi-borehole modes and of a multi-mode dispersion wave and multi-mode dispersion estimation systems

Aspects of the subject technology relate to systems and methods for identifying the quality of cement bonding of an exterior surface of a wellbore casing to an Earth formation. Methods of the present disclosure may allow for bond indexes to be identified in real-time as a cementing operation is performed even when tools that perform the cementing operation generate acoustic noise that interfere with measurements used to evaluate cement bonding quality. These methods may include transmitting acoustic signals, receiving acoustic signals, filtering the received acoustic signals, identifying magnitude and attenuation values to associate with the received acoustic signals, and comparing trends in the magnitudes with the identified attenuation values. These methods may also include correcting attenuation values associated with measured data based on a set of correction rules such that bond indexes can be identified. Such correction rules may be associated with data generated by a computer model.

Real-time cement bond logging based on correlation

Methods to estimate formation shear wave slowness from multi-firings of different types of acoustic sources and multi-mode dispersion estimation systems are presented. The method includes obtaining waveform data of waves traversing through a downhole formation, where the waves are generated from multi-firings of different types of acoustic sources. The method also includes performing a multimode dispersion analysis of the waveform data for each firing of the multi-firings, and removing one or more tool waves generated from the multi-firings. The method further includes determining a formation type of the formation the waves traverse based properties of the waves and determining an initial shear wave slowness estimate of the waves. The method further includes generating a modeling of the waves, and reducing a mismatch between the modeling of the waves and a slowness dispersion of the waves to improve the modeling of the waves.

Methods to estimate formation shear wave slowness from multi-firings of different types of acoustic sources and multi-mode dispersion estimation systems

To generate dispersion curves for acoustic waves in a radially layered system, a matrix M containing solutions to the wave equation subject to the boundary conditions of the system is constructed. The reciprocal condition number (RCN) of the matrix M is determined as a function of acoustic wave frequency and slowness. The local minima of the RCN in the frequency-slowness plane produces the dispersion curves corresponding to allowable acoustic modes in the system. A sensitivity analysis which identifies the dispersion curves dependent on a selected parameter. The dispersion curves independent of the perturbed parameters are eliminated by perturbing the modeling parameters and generating the RCN of the perturbed matrix M and then subtracting the RCN values of the unperturbed matrix M, leaving the dispersion curves that exhibit dependence on the selected parameter.

Acoustic dispersion curve identification based on reciprocal condition number

Techniques for calculating and visually presenting multiple acoustic modes that have different formation slowness are disclosed herein. The techniques include methods for receiving time-domain waveforms from adjacent formations in a borehole, processing each of the time-domain waveforms to generate frequency-domain spectrums, selecting frequency and slowness values, and predicting travel time of a mode associated with the slowness value. In some aspects, the method further includes steps for calculating a semblance difference of the frequency-domain spectrums based on the frequency value, the slowness value and the predicted travel time. Systems and computer-readable media are also provided.

Mapping wave slowness using multi-mode semblance processing techniques

A method and system for inspecting cement downhole. The method may comprise inserting an inspection device inside a tubing. The inspection device may comprise a centralizing module as well as a transducer, an azimuthal receiver, and a telemetry module. The method may further comprise activating the transducer, wherein the transducer generates a low-frequency cylindrical acoustic wave with normal incidence, detecting the locations and strengths of resonances generated, and creating a graph with an information handling system for analysis.

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Houston, TX, United States of America

Jiajun Zhao