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.

A solid-state hydrophone may include a piezoelectric rod positioned between at least two electrodes. The piezoelectric rod may be disposed within a metallic housing to shield the piezoelectric rod and its connections from acoustic and electromagnetic waves. The piezoelectric rod and the electrodes may be potted in the mechanical housing using a potting material that may be positioned adjacent to the piezoelectric rod. At least a layer of the potting material may be positioned between the piezoelectric rod and the metallic housing to physically separate the piezoelectric rod from the metallic housing.

Waves from cement bond logging with a sonic logging-while-drilling tool (LWD-CBL) are often contaminated with tool waves and may yield biased CBL amplitudes. The disclosed LWD-CBL wave processing corrects the first echo amplitudes of LWD-CBL before calculating the BI. The LWD-CBL wave processing calculates a tool wave amplitude and a phase angle difference as the difference of the phases between the tool waves and casing waves. The tool waves are then used to correct the LWD-CBL casing wave amplitude and remove errors introduced from tool waves. In conjunction with the sets of operations described, the LWD-CBL wave processing also include array preprocessing operations. Array preprocessing may employ variation of bandpass filtering and frequency-wavenumber (F-K) filtering operations to suppress tool wave.

An acoustic logging tool may comprise a center load carrying pipe, a receiver module connected to the center load carrying pipe, one or more transmitter modules connected to the center load carrying pipe, and one or more mass modules connected to the center load carrying pipe.

Systems and methods include a computer-implemented method for predicting fluid holdups along the borehole or the pipe on surface and to perform fluid typing and fluid properties characterization. Acoustic waves are transmitted by an array of acoustic wave transducers. Each transducer is configured to transmit acoustic waves at a different frequency. The acoustic waves are received by an array of acoustic wave receivers fixed on the bow centralizer on the tool used in the borehole. Each receiver is configured to receive only the given frequency of a given transducer, forming a receiver-transducer pair for the given frequency. Acoustic speeds measured at each given frequency and analyzed. A model is generated based on the analyzing. The model is configured to predict fluid holdups across the borehole and to perform fluid typing and fluid properties characterization in one phase, two phase, and three phase applications of gas, oil, and water.

Methods, systems, and program products are disclosed for implementing acoustic logging and determining wellbore material characteristics. In some embodiments, a method may include determining a polar differential signal for each of one or more pairs of azimuthally offset acoustic measurements within a wellbore. A reference azimuth is identified based, at least in part, on comparing the polar differential signals to a modeled bonding differential signal within a target response window. The method further includes determining differences between an acoustic measurement at the reference azimuth and acoustic measurements at one or more other azimuths and determining a wellbore material condition based, at least in part, on the determined differences.

The present disclosure discloses a method of obtaining a seismic while drilling signal. The method comprises the following steps: arranging geophones by using a first observation method to obtain a first seismic reference signal and a second seismic reference signal; arranging geophones by using a second observation method to obtain first seismic data; arranging geophones by using a third observation method to obtain second seismic data; comparing the first seismic reference signal with the second seismic reference signal to obtain a first output reference signal, and optimizing the first output signal to obtain a second output reference signal. The present disclosure obtains square matrix and near-wellhead seismic while drilling data through the combination of geophone square matrix combined observation, near-wellhead observation, and survey line observation, the data acquisition efficiency is relatively high, the signal-to-noise ratio is high, and thus, the problem of near-surface noise interference is effectively solved.

Downhole measurement systems and methods include deploying a bottomhole assembly having a multipole transmitter into a formation and transmitting acoustic signals into the formation. The multipole transmitter is of order n ≥ 2. Acoustic signals are received at respective receivers that are circumferentially aligned with the multipole transmitter, and are axially offset from the multipole transmitter, and axially offset from each other. The order of the first and second multipole receivers are equal to the order of the multipole transmitter. A controller is used to obtain first and second acoustic multipole data from the first and second multipole receivers at one or more azimuthal angles of a rotation of the bottomhole assembly in a formation during a drilling operation. Acoustic azimuthal anisotropy of the formation is determined from the first acoustic multipole data and the second acoustic multipole data.

A method of determining a shear-wave attenuated vertical component vertical seismic profile (VSP) dataset is disclosed. The method includes, obtaining a multi-component VSP dataset, including a vertical and a horizontal component, transforming the vertical component into a vertical spectrum and the horizontal component into a horizontal spectrum, and designing a band-pass filter based, at least in part, on an energetic signal of the horizontal spectrum. The method further includes determining a muted vertical amplitude spectrum by applying the pass-band filter to an amplitude spectrum of the vertical spectrum, determining an estimated noise model based on the muted vertical amplitude spectrum and the vertical spectrum; and determining the shear-wave attenuated vertical component VSP dataset by adaptively subtracting the estimated noise model from the vertical component of the multi-component VSP dataset. A system including a seismic source, a plurality of seismic receivers, and a seismic processor for executing the method is disclosed.

A method for performing a formation-related operation based on corrected vertical seismic profile (VSP) data of an earth formation includes performing a VSP survey and applying a normal moveout (NMO) correction equation to the survey data that is a function of source offset to wellhead. The method also includes solving the NMO correction equation using a simulated annealing algorithm having an object function that is a coherence coefficient of semblance analysis of an NMO corrected reflection event within a time window to provide NMO corrected data. The method further includes performing the formation-related operation at at least one of a location, a depth and a depth interval based on the VSP NMO corrected data.