Noise can be attenuated in marine seismic data from a marine seismic survey. A first near-continuous measurement of a wavefield and a second near-continuous measurement of the wavefield recorded from a marine seismic survey can be equalized, a coherent portion of the equalized second near-continuous measurement can be collapsed, and a noise model can be derived. The noise model can be subtracted from the second near-continuous measurement.

Processes and systems described herein are directed to imaging a subterranean formation from seismic data recorded in a marine survey with moving marine vibrators. The marine vibrators generate random sweeps with random sweep signatures. Processes and systems generate an up-going pressure wavefield from measured pressure and vertical velocity wavefield data recorded in the marine survey and obtain a downgoing vertical acceleration wavefield that records source wavefields, directivity, source ghosts, and random signatures of the random sweeps. The downgoing vertical acceleration wavefield data is deconvolved from the up-going pressure wavefield to obtain a subsurface reflectivity wavefield that is used to generate an image of the subterranean formation with reduced contamination from source wavefields, directivity, source ghosts, and random signatures of the random sweeps.

Techniques are disclosed relating to deblending of sources in multi-source geophysical survey data, including marine or land-based data. Recorded data may be aligned to a primary source. A deblending procedure may be iteratively applied to produce a residual term and deblended estimates for the primary source and one or more secondary sources. Following an iteration of the deblending procedure, the resultant data may be sorted according to a domain that renders the one or more secondary sources incoherent with respect to the primary source. The domain used for sorting may be different from a domain used to sort during an immediately prior iteration. In embodiments, the deblending procedure may use coherency filtering, and the coherency filtering may be weighted according to a signal-to-noise metric generated from the data being deblended.

Techniques for determining a wellbore drilling path includes identifying input seismic data associated with a subterranean zone that includes a wellbore drilling target. The input seismic data includes primary seismic events and multiple seismic events. The input seismic data is processed to remove the multiple seismic events and at least one of the primary seismic events from the input seismic data. An orthogonalization of the processed input seismic data is performed to recover the at least one primary seismic event into a seismic image of the subterranean zone that excludes at least a portion of the multiple seismic events. A wellbore path is determined from a terranean surface toward the wellbore drilling target for a drilling geo-steering system based on the seismic image of the subterranean zone.

A method includes acquiring seismic data of a region that utilizes multiple seismic energy sources and seismic energy receivers where the seismic data include blended seismic data for a number of emissions from a corresponding number of the multiple seismic energy sources; determining spatially distributed coherent noise properties for the region using the blended seismic data; via the spatially distributed coherent noise properties, modeling coherent noise as at least two coherent noise models for at least two of the emissions from a corresponding at least two of the multiple seismic energy sources; via the coherent noise models, attenuating coherent noise in a portion of the blended seismic data to generate coherent noise attenuated blended seismic data; deblending the coherent noise attenuated blended seismic data to generate deblended seismic data; and rendering an image of at least a portion of the region to a display using the deblended seismic data.

Systems and methods include a method for deblending signal and noise data. A shot domain for actual sources, a receiver domain for virtual sources, and a receiver domain for actual sources are generated from blended shot data. A dictionary of signal atoms is generated. Each signal atom includes a small patch of seismic signal data gathered during a small time window using multiple neighboring traces. A dictionary of noise atoms is generated. Each noise atom includes a small patch of seismic noise data gathered during a small time window using multiple neighboring traces. A combined signal-and-noise dictionary is generated that contains the signal atoms and the noise atoms. A sparse reconstruction of receiver domain data is created from the combined signal-and-noise dictionary. The sparse reconstruction is split into deblended data and blending noise data based on atom usage to create deblended shot domain gathers for actual sources.

Various aspects described herein relate to a machine learning based signal recovery. In one example, a computer-implemented method of noise contaminated signal recovery includes receiving, at a server, a first signal including a first portion and a second portion, the first portion indicative of data collected by a plurality of sensors, the second portion representing noise; performing a first denoising process on the first signal to filter out the noise to yield a first denoised signal; applying a machine learning model to determine a residual signal indicative of a difference between the first signal and the first denoised signal; and determining a second signal by adding the residual signal to the first denoised signal, the second signal comprising (i) signals of the first portion with higher magnitudes than the noise in the second portion, and (ii) signals of the first portion having lower magnitudes than the noise in the second portion.

Techniques are disclosed relating to deblending of sources in multi-source geophysical survey data, including marine or land-based data. Multiple sets of deblended receiver traces are generated by iteratively applying a coherency filter to estimated sets of deblended receiver traces and updating a residual until a termination condition is reached. In some embodiments, applying the coherency filter during a current iteration may include determining coefficients of the coherency filter based on estimated sets of deblended receiver traces from an immediately prior iteration. In further embodiments, applying the coherency filter may include applying a 3D projection filter, such as an fxy projection filter.

Systems and methods for filtering interface waves from single component seismic data are disclosed. In one embodiment, a method of filtering seismic data includes comparing amplitude coefficients of a matrix storing the seismic data in a time-frequency domain against an amplitude threshold, and comparing frequencies of the matrix against a maximum expected frequency of noise. The method further includes, for each amplitude coefficient having less than the amplitude threshold and an associated frequency less than the maximum expected frequency of noise, scaling the amplitude coefficient to reduce its value. The method also includes performing an inverse time-frequency transformation on the matrix to generate a noise model in a time domain, and subtracting the noise model from the seismic data in the time domain to generate filtered seismic data.

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.