A method, including: generating updated velocity models, each corresponding to one of a plurality of initial velocity models of intersecting 2D seismic survey lines, wherein updates to the plurality of initial velocity models are computed by imposing a seismic-tie regularization constraint on an inversion process that inverts for the updates to the plurality of initial velocity models, and the seismic-tie regularization constraint causes the updated velocity models to have consistent values for depth of seismic reflectivity at intersecting spatial locations.

Simultaneous inversion of multi-vintage seismic data obtains seismic data for vintages and generates an initial earth model for each vintage. A cost function includes a data norm term having for at least one pair of vintages of seismic data a difference norm between a difference in obtained seismic data for the at least one pair of vintages and a difference in modeled seismic data for the at least one pair of vintages. The cost function also includes a model norm term for each pair of vintages selected from at least three vintages of seismic data. Each model norm term includes a difference norm between earth models for a given pair of vintages. A closure relationship is imposed on all earth models. The earth models are adjusted for the vintages to drive the cost function to a minimum and to produce updated earth models.

Computing systems, computer-readable media, and methods for seismic processing. The method includes receiving seismic data including acquired seismic waveforms that were acquired from a seismic receiver and represent a subterranean area, generating synthetic waveforms based on an initial model of the subterranean area, determining a model error by minimizing a local travel time shift error between one or more of the acquired seismic waveforms and one or more of the synthetic waveforms, and adjusting the initial model based on the model error to generate an adjusted model.

The current disclosure is directed to methods and systems to determine properties of a subterranean formation located below a body of water. The methods and systems compute synthetic pressure and velocity vector wavefields that represent acoustic energy interactions within a model environment that comprises a model body of water located above a model subterranean formation. The model environment is separated into a stationary region and a time-varying region. The methods and systems include determining properties of the subterranean formation by iteratively adjusting the model environment to approximate the actual subterranean formation. The model environment is iteratively adjusted until a minimum difference between the synthetic pressure and velocity vector wavefields computed for each change to the model environment and actual pressure and velocity wave fields obtained from a marine seismic survey of the subterranean formation is achieved.

A method and system for prospecting for gas hydrates and gas hydrates over free gas is disclosed. The method includes using well log data to form a rock physics model to generate synthetic seismic representing hydrate and hydrate-over-gas models. Spectral decomposition is applied to the synthetic seismic and to field seismic from the prospecting area, forming low frequency narrow band data sets. From mapped potential sands in the field data, compare positive amplitude dominated event in the narrow band field data to the narrow band synthetics for gas hydrates. Compare negative amplitude dominated event in the narrow band field data to the narrow band synthetics for gas or gas hydrate-over gas. From these comparisons, perform modeling to determine saturation and thickness for hydrates and hydrates-over-gas.

Limitations in accuracy and computing power requirements impeding conventional Kirchhoff migration and reverse time migration are overcome by using the wave-equation Kirchhoff, WEK, technique with Kirchhoff migration. WEK technique includes forward-propagating a low-frequency wavefield from a shot location among pre-defined source locations, calculating an arrival traveltime of a maximum amplitude of the low-frequency wavefield, and applying Kirchhoff migration using the arrival traveltime and the maximum amplitude.

A method for variogram modeling is disclosed. The method includes obtaining a synthetic well data and a well data for facies or petrophysical properties of interest in a targeted reservoir zone, training machine learning models using the synthetic well data as inputs and outputting a plurality of final variogram parameters predicted by using a plurality of machine learning models for the facies or petrophysical properties of interest in the targeted reservoir zone, wherein the well data for the facies or petrophysical properties of interest in the targeted reservoir zone is used as input.

A method for generating seismic attribute gathers, the method including: computing, with a computer, seismic images with a field dataset; generating, with a computer, synthetic data corresponding to the seismic images; computing, with a computer, an attribute volume by applying an expectation method to the synthetic data; mapping, with a computer, the attribute volume to the seismic images; and generating, with a computer, seismic attribute gathers by stacking the seismic images mapped to the attribute volume.

Computing device, computer instructions and method for correcting an image, of a surveyed surface, due to a free-surface reflection. The method includes calculating a free surface reflection operator for a seismic source displaced in water based on a position of the source, and an air-water interface datum; receiving recorded seismic data d recorded with seismic sensors (r), wherein the recorded seismic data is associated with a pressure and/or a particle motion produced by a seismic wave in earth; correcting the recorded seismic data d based on the free surface reflection operator to obtain transformed seismic data; and generating an image of the surveyed subsurface, based on the transformed seismic data, wherein the image is indicative of various layers of the earth. The free surface reflection operator varies while a source signal is being emitted by the source.

Computing device, computer instructions and method for estimating a broadband wavelet associated with a given seismic data set. The method includes receiving broadband seismic data; constructing and populating a misfit function; calculating the broadband wavelet based on the misfit function and the broadband seismic data; and estimating physical reservoir properties of a surveyed subsurface based on the broadband wavelet. The broadband wavelet is constrained, through the misfit function, by (1) an amplitude only long wavelet, and (2) an amplitude and phase short wavelet. The amplitude and phase short wavelet is shorter in time than the amplitude only long wavelet.