An inversion method for a multilayer seabed geoacoustic parameter in a shallow sea, includes: establishing a plurality of seabed models, different seabed models corresponding to different layer numbers, randomly generating a value of each geoacoustic parameter based on a preset change range corresponding to each geoacoustic parameter, then calculating to obtain a theoretical sound pressure value, and comparing the theoretical sound pressure value with an actual sound pressure value, adjusting and updating the value of each geoacoustic parameter according to the comparison result until the obtained theoretical sound pressure value is matched with the actual sound pressure value, and obtaining a target geoacoustic parameter value; calculating to obtain a BIC value corresponding to each seabed model; and taking the seabed model with the minimum BIC value as a target seabed model, and taking a target geoacoustic parameter value corresponding to the target seabed model as a target inversion parameter value.

Reducing migration distortions in migrated images of the Earth's subsurface. Recorded seismic data may be migrated, using a migration velocity model, to generate a migration image comprising ADCIGs with distortions. Synthetic seismic data may be generated, using the migration velocity model, for a grid of point scatterers. The synthetic seismic data may be migrated, using the migration velocity model, to generate impulse responses for the point scatterers. The impulse responses are used as point spread functions (PSFs) which approximate the blurring operator, e.g., the Hessian. An optimal reflectivity model may be selected using image-domain least-squares migration (LSM), based on the PSFs, with regularization of the difference between the migration image and a reflectivity model and a total variation (TV) regularization of the reflectivity model in the spatial and angular domains. An image of the optimal reflectivity model may be generated with reduced migration distortions compared to the original migration image.

A method of seismic exploration above a region of the subsurface of the earth containing structural or stratigraphic features conducive to the presence, migration, or accumulation of hydrocarbons comprises setting a tow depth of a resonant seismic source, producing a resonant frequency at a first amplitude with the resonant seismic source at the tow depth, detecting a depth excursion from the tow depth, reducing an amplitude of the mass from the first amplitude to a second amplitude, preventing the mass from contacting at least one of the first end stop or the second end stop based on reducing the amplitude to the second amplitude, correcting the depth excursion to return the resonant seismic source to the tow depth, and increasing the amplitude from the second amplitude to produce the resonant frequency with the resonant seismic source at the tow depth.

A method of seismic exploration above a region of the subsurface of the earth containing structural or stratigraphic features conducive to the presence, migration, or accumulation of hydrocarbons comprises setting a tow depth of a resonant seismic source, producing a resonant frequency at a first amplitude with the resonant seismic source at the tow depth, detecting a depth excursion from the tow depth, reducing an amplitude of the mass from the first amplitude to a second amplitude, preventing the mass from contacting at least one of the first end stop or the second end stop based on reducing the amplitude to the second amplitude, correcting the depth excursion to return the resonant seismic source to the tow depth, and increasing the amplitude from the second amplitude to produce the resonant frequency with the resonant seismic source at the tow depth.

A method includes receiving over a network from one or more seismic sensors a data set characterizing a seismic event generating a seismic wave. Based on the data set, a time of arrival and intensity of the seismic wave at a predetermined location is calculated. The predetermined location has one or more mitigation devices. Whether the intensity of the seismic wave exceeds a predetermined seismic intensity threshold is determined. If the intensity of the seismic wave exceeds the predetermined seismic intensity threshold, the one or more mitigation devices are activated.

A method is described for generating a subsurface model using stochastic full waveform inversion by receiving a seismic dataset representative of a subsurface volume of interest; performing stochastic full waveform inversion of the seismic dataset to generate a long wavelength subsurface model; and performing full waveform inversion of the seismic dataset using the long wavelength subsurface model as a starting model to generate an improved subsurface model. The method may further include performing seismic imaging of the seismic dataset using the improved subsurface model to generate a seismic image and identifying geologic features based on the seismic image. The method may be executed by a computer system.

A method is described for generating a subsurface model using stochastic full waveform inversion by receiving a seismic dataset representative of a subsurface volume of interest; performing stochastic full waveform inversion of the seismic dataset to generate a long wavelength subsurface model; and performing full waveform inversion of the seismic dataset using the long wavelength subsurface model as a starting model to generate an improved subsurface model. The method may further include performing seismic imaging of the seismic dataset using the improved subsurface model to generate a seismic image and identifying geologic features based on the seismic image. The method may be executed by a computer system.

One or more first sensors may be configured to sense seismic signals and one or more second sensors may be configured to sense electromagnetic crosstalk signals. The second sensors are not responsive to the seismic signals. The data from the first and second sensors may be recorded as first data and second data, respectively. The first data may be modified based on the second data to remove the electromagnetic crosstalk noise form the seismic data.

A distributed acoustic sensing (DAS) system for determining an acoustic event may include an interferometer and an acoustic event detection processing device. The interferometer may measure DAS data from sensed signals from a sensing fiber deployed in a wellbore. The acoustic event detection processing device may determine an acoustic event in the wellbore from an out-of-band signal using the DAS data by performing operations. The operations can include determining a first acoustic event and a second acoustic event from the DAS data. The operations can include determining a first set of aliased frequencies from the first acoustic event and a second set of aliased frequencies form the second acoustic event. The operations can include determining, using an intersection of the first set of aliased frequencies and the second set of aliased frequencies, a frequency or amplitude of out-of-band signals that are usable to determine the at least one acoustic event.

The present disclosure belongs to the technical field of seismic exploration imaging, and relates to an interpretive-guided velocity modeling seismic imaging method and system, a medium and a device. The method comprises the following steps: S1. performing first imaging on a given initial velocity model to obtain a first imaging result; S2. performing relative wave impedance inversion on the first imaging result to obtain a relative wave impedance profile; S3. performing Curvelet filtering on the relative wave impedance profile to obtain a first interpretation scheme; S4. superposing the first interpretation scheme and the initial velocity model to obtain a new migration velocity field; S5. performing second imaging on a new migration velocity field to obtain a second imaging result; and S6. repeating steps S2-S4 for the obtained second imaging result until a final seismic imaging result is obtained.