Reducing casing wave effects on sonic logging data by positioning two or more receivers in a borehole in a subsurface formation; receiving, at two or more receivers in a borehole in a subsurface formation, a first signal associated with a first acoustic signal originating from a first transmitter position; receiving, at the two or more receivers, a second signal associated with a second acoustic signal originating from a second transmitter position; creating a dataset based on the first signal and the second signal; identifying casing wave signals in the dataset based at least in part on the second signal; calculating inverse-phase casing wave signals based at least in part on the casing wave signals and the second signal; and reducing effects of the casing wave signals on the dataset using the inverse-phase casing wave signals.

A method of probabilistically estimating a velocity of a plunger of a beam pump may comprise continuously monitoring well acoustics using a plurality of passive acoustic sensors attached to external structures of the beam pump; digitizing outputs of the plurality of passive acoustic sensors and sending the digitized outputs to a computing device for storage and processing; and using the digitized outputs of the plurality of passive acoustic sensors, estimating a probability of the velocity of the plunger using a hidden Markov model (HMM) to represent a probability of a position and the probability of the velocity of the plunger, the HMM comprising a state space model and an observational model.

A method and system for identifying bonding between a material and tubing. The method may include disposing an acoustic logging tool in a wellbore, wherein the acoustic logging tool comprises a transmitter, a receiver, or a transceiver, broadcasting a shaped signal with the transmitter such that the shaped signal interacts with a boundary of a casing and a material and recording a result signal from the boundary with the receiver. The method may further comprise identifying a cut-off time to be applied to the result signal, transforming the result signal from a time domain to a frequency domain, selecting one or more modes sensitive to a bonding at the boundary between the casing and the material, computing a decay rate of the one or more modes that were selected based at least one or more decay curves, and converting the decay rate to a bonding log.

Methods, systems, devices, and products for well logging. Methods include conveying a logging tool in the borehole on a carrier; obtaining a borehole image over at least one interval of borehole depth from well logging measurements with a downhole imaging instrument; obtaining acoustic information representative of acoustic reflections from a far-field region of the formation; obtaining quantitative borehole fluid information indicative of properties of a formation fluid in a near-field region of the borehole; generating a borehole connectivity fracture model of the formation in dependence upon the borehole image, the quantitative borehole fluid information, and the acoustic information. Methods may include identifying near-field fractures from the borehole image, and/or identifying far-field fractures from the acoustic information. Methods may include generating a fracture interpretation correlating the near-field fractures with the far-field fractures, and generating the borehole connectivity fracture model of the formation in dependence upon the fracture interpretation.

A method and system for locating a reflector in a formation. The method may comprise broadcasting a sonic waveform as a shear formation body wave or a compressional formation body wave into the formation, recording a reflected wave from a reflector with the one or more receivers as dipole data by the dipole receiver and quadrupole data by the quadrupole receiver, and processing the dipole data and the quadrupole data with an information handling system to determine a location of the reflector from the borehole sonic logging tool. The system may comprise a borehole sonic logging tool and an information handling system. The borehole sonic logging tool may comprise one or more transmitters configured to transmit a sonic waveform into a formation and one or more receivers configured to record a reflected wave as a dipole receiver for dipole data and a quadrupole receiver for quadrupole data.

A method can include receiving channels of data from equipment responsive to operation of the equipment in an environment where the equipment and environment form a dynamic system; defining a particle filter that localizes a time window with respect to the channels of data; applying the particle filter at least in part by weighting particles of the particle filter using the channels of data, where each of the particles represents a corresponding time window; and selecting one of the particles according to its weight as being the time window of an operational state of the dynamic system.

A system and method for acoustically profiling a wellbore while drilling, and which identifies depths in the wellbore where the wellbore diameter is enlarged or has highly fractured sidewalls. These depths are identified based on monitoring either travel time or signal strength of acoustic signals that propagate axially in the wellbore. Correlating wellbore depth to travel time of a signal traveling downhole inside of a drill string and uphole outside of the drill string yields an average signal velocity in the wellbore. Depths having a lower average signal velocity indicate where the wellbore diameter is enlarged or has highly fractured sidewalls. These depths are also identified by generating separate acoustic signals inside and outside of the drill string, comparing signal strengths of signals reflected from the wellbore bottom, and identifying the depths based on where there is an offset in the strengths of the reflected signals.

A method is disclosed for radiaiiy profiling shear velocities of flexural wave modes in a formation. The method includes establishing sensitivity kernels with two non-dimensionalized parameters and using said sensitivity kernels to perform an inversion for radial shear wave velocity profiles. This method may be used for LWD, MWD, or wireline logging operations.

A method for assessing and/or removing one or more motion effects from logging while drilling (LWD) measurement data may include disposing a borehole logging tool into a borehole, wherein the borehole logging tool is disposed on a bottom hole assembly (BHA), taking one or more measurements at one or more depth in the borehole with the borehole logging tool to form a measurement data set, and identifying one or more pipe breaks and one or more stations in the measurement data set. The method extracts measurement data at one or more pipe breaks and one or more stations to form a non-motion measurement data set, providing answer products from the non-motion measurement data set. The method may further include removing the one or more pipe breaks and one or more stations from the measurement data set to form a corrected measurement data set and providing one or more answer products.

Example ultrasonic transducers for measuring formation velocities are disclosed herein. An example apparatus includes a housing and an acoustic transducer having a first surface and a second surface opposite the first surface. The acoustic transducer is at least partially disposed in the housing. The example apparatus includes a window supported by the housing. At least a portion of the first surface of the acoustic transducer is in contact with the window. The housing and the window are to form a fluid seal for the acoustic transducer.