Systems and methods develop a three-dimensional model of a subterranean formation based on vertical seismic profiles at a plurality of well locations. This approach can include receiving seismic data for the subterranean formation including the vertical seismic profiles; for each vertical seismic profile, injecting a ground force into the vertical seismic profile to provide a reference trace at depth zero to estimate energy loss in each receiver providing data in the vertical seismic profile and estimating time and depth variant quality factors for the well location associated with the vertical seismic profile based on the seismic profile; estimating quality factors for points within a three-dimensional volume representing the subterranean formation by interpolating between the time and depth variant quality factors for the location associated with each vertical seismic profile; and combining estimated quality factors to generate a three-dimensional quality factor model of the three-dimensional volume representing the subterranean formation.

Methods for correcting eccentering effects on echoes detected from ultrasonic pulses emitted by a transducer of a downhole tool. Echo envelope amplitude, azimuth, and location for each echo is utilized to assess echo amplitude sensitivity to geometric and spatial characteristics of the downhole tool within the wellbore. Echo envelope amplitudes are corrected for eccentering effects based on the assessed sensitivity. A visual representation of the corrected echo envelope amplitudes is the generated. Also disclosed herein are tangible, non-transient, computer-readable media comprising instructions executable by a processor to carry out the methods, as well as systems including downhole tools and processing devices operable to carry out the methods.

Disclosed are methods, systems, and computer-readable medium to perform operations including: receiving seismic data acquired by at least one receiver of a geologic survey system configured to perform a geologic survey of a subterranean formation, wherein the seismic data is associated with reflected acoustic signals generated by at least one source of the geologic survey system; calculating a ground force signal by stacking the acoustic signals generated by the least one source; calculating, using the ground force signal, a time and depth variant quality factor (Q) of the subterranean formation; and compensating, based on the time and depth variant Q, attenuation in the seismic data.

Embodiments relate to noncontact determination of nonlinearities. Initially, a first and second primary signal are preconditioned to produce a first and second tone capable of reaching a target granular media. Using a sound source, the first and second primary signals are emitted such that the first and second primary signals combine in a nonlinear fashion in the target granular media to produce low frequency acoustic tone that is a difference between the first and primary signals. An acoustic pulse is received by an acoustic receiver, and a quadratic nonlinearity coefficient and an acoustic pressure field are determined based on the acoustic pulse. At this stage, a sediment shear strength of the granular media is correlated to the quadratic nonlinearity coefficient to generate a shear strength lookup table.

Disclosed and described herein are systems and methods used to analyze ultrasonic waves and nondestructively infer acoustic wave velocities and dynamic elastic properties of materials. Disclosed methods employ the selective rotation of ultrasonic transducers immersed in a liquid (water) adjacent to the sample under study.

Methods for correcting eccentering effects on echoes detected from ultrasonic pulses emitted by a transducer of a downhole tool. Echo envelope amplitude, azimuth, and location for each echo is utilized to assess echo amplitude sensitivity to geometric and spatial characteristics of the downhole tool within the wellbore. Echo envelope amplitudes are corrected for eccentering effects based on the assessed sensitivity. A visual representation of the corrected echo envelope amplitudes is the generated. Also disclosed herein are tangible, non-transient, computer-readable media comprising instructions executable by a processor to carry out the methods, as well as systems including downhole tools and processing devices operable to carry out the methods.

The harmonic wave, which is oscillation of a physical value along one direction of propagation in a homogeneous medium, is recorded by means of sensors along the direction of propagation of the oscillation at least at five points equally spaced from each other. The output signals of the sensors are converted into the corresponding complex spectral amplitudes corresponding to the frequency decomposition of the output signals. A model of harmonic wave propagation in a homogeneous medium is created, in which for any oscillation frequency the wave is represented as descending and ascending exponentially decaying harmonic waves propagating in opposite directions. The absolute values of the complex spectral amplitudes of the output signals of the sensors at each frequency are used as input data for equations comparing the absolute values of the complex amplitudes with the created model of wave propagation. By solving the obtained equations, the total complex amplitudes of the descending and ascending waves and the complex propagation constant of oscillations at each frequency are determined and the characteristics of the boundaries of the homogeneous medium are determined basing on the ratio of the complex amplitudes of the descending and ascending waves, and the characteristics of the homogeneous medium are determined basing on the phase velocity and attenuation coefficient of the wave.

Noise signals can be attenuated on a trace-by-trace basis from traces of marine seismic survey data to yield a signal component and a noise component. A signal-to-noise ratio (SNR) variance of a plurality of traces comprising the signal component can be less than an SNR variance of the plurality of traces comprising the marine seismic survey data. Signal leakage can be attenuated from the noise component to yield a signal leakage component. A seismic image of a subsurface location can be generated based on the signal component and the signal leakage component.

A method, including: obtaining a velocity model generated by an acoustic full wavefield inversion process; generating, with a computer, a variable Q model by applying pseudo-Q migration on processed seismic data of a subsurface region, wherein the velocity model is used as a guided constraint in the pseudo-Q migration; and generating, with a computer, a final subsurface velocity model that recovers amplitude attenuation caused by gas anomalies in the subsurface region by performing a visco-acoustic full wavefield inversion process, wherein the variable Q model is fixed in the visco-acoustic full wavefield inversion process.

Embodiments relate to noncontact determination of nonlinearities. Initially, a first and second primary signal are preconditioned to produce a first and second tone capable of reaching a target granular media. Using a sound source, the first and second primary signals are emitted such that the first and second primary signals combine in a nonlinear fashion in the target granular media to produce low frequency acoustic tone that is a difference between the first and primary signals. An acoustic pulse is received by an acoustic receiver, and a quadratic nonlinearity coefficient and an acoustic pressure field are determined based on the acoustic pulse. At this stage, a sediment shear strength of the granular media is correlated to the quadratic nonlinearity coefficient to generate a shear strength lookup table.