Numerous techniques and apparatus are disclosed relating to the performance of 4D marine geophysical surveys over at least first and second areas covered, respectively, by first and second preexisting baseline surveys. Performing the monitor surveys may include deploying a monitor survey streamer layout that can be used to repeat streamer positions of both the first and the second preexisting baseline surveys, and using the monitor survey streamer layout to perform the monitor survey over the first and second areas in a manner that repeats all streamer positions of the first preexisting baseline survey when over the first area, and that repeats all streamer positions of the second preexisting baseline survey when over the second area. Streamer layouts corresponding to the first and second preexisting baseline surveys may differ in at least one of the following characteristics: streamer separation or total number of streamers.

A method for seismic processing includes receiving measured seismic data collected by recording seismic waves that propagate through a subterranean domain, simulating synthetic seismic data using a model of the subterranean domain, generating a first time-space panel including the measured seismic data and a second time-space panel including the synthetic seismic data, applying a first moving window to the first time-space panel and a second moving window to the second time-space panel, determining a misfit by comparing the measured seismic data in the first moving window with the synthetic seismic data in the second moving window, and adjusting the model based on the misfit.

Methods and apparatus are described for performing a 4D monitor marine seismic survey that repeats a previous survey. A number of sources may be used during the 4D monitor survey that differs from a number of sources that were used during the previous survey. Shot points from the previous survey are repeated by the 4D monitor survey, and additional shot points may be produced during the 4D monitor survey that were not produced during the previous survey. Embodiments enable efficiency and data quality improvements to be captured during 4D survey processes, while preserving repeatability.

This disclosure presents processes and systems for estimating a source wavelet from seismic data recorded in a seismic survey of a subterranean formation. In one aspect, a base wavelet is determined based on recorded seismic traces obtained in a seismic survey of a subterranean formation. Processes and systems include a phase-only wavelet based on the base wavelet and the recorded seismic data. An estimated source wavelet is obtained by convolving the base wavelet with the phase-only wavelet. Properties of the subterranean formation are determined based on the estimated source wavelet and the recorded seismic data.

A system and method can be used for to calibrating time-lapse seismic volumes by cross-migration rescaling and reorientation for use in determining optimal wellbore placement or production in a subsurface environment. Certain aspects include methods for cross-migration of data sets processed using different migration techniques. Pre-processing of the data sets, optimization of rescaling and reorientation, and identification of adjustment parameters associated with minimum global error can be used to achieve a time-dependent formation data set that addresses error in all input data sets.

A modified velocity model different from an initial velocity model is determined for migrating a vintage of 4D seismic data. The modified velocity model minimizes differences between a reference vintage migrated using the initial velocity model and the vintage migrated using the modified velocity model.

A data set comprises data obtained by seismic imaging of a region of interest during an observation period. An intrinsic geological variability of a region is determined from the comparison of reception signals for neighbor bins as a function of a difference in signal geometry for the neighbor bins.

A data acquisition program, which includes core, image log, microseismic, DAS, DTS, and pressure data, is described. This program can be used in conjunction with a variety of techniques to accurately monitor and conduct well stimulation.

A backpropagation enabled model is trained for estimating time-lapse property changes of a subsurface volume. Synthetic models of the subsurface volume are generated, with pre-determined property changes before and after a time lapse. These models are used to compute baseline-monitor pairs of synthetic seismic traces before and after the time lapse, wherein the baseline synthetic traces are computed from the synthetic model before the time lapse and the monitor synthetic traces are computed from the synthetic model after the time lapse. A ground truth 4D attribute characterizing the time-lapse property changes in the synthetic models is defined, and a backpropagation enabled model is trained by feeding the baseline-monitor pairs of synthetic seismic traces and the corresponding ground truth 4D attribute. The thus obtained trained backpropagation enabled model can be used to estimate time-lapse property changes of the actual subsurface Earth volume from actual baseline-monitor pairs of seismic traces.

A workflow using techniques for improving signal-to-noise ratio and decreasing interferences for Low-Frequency Distributed Acoustic Sensing is described.