Generating spectrally enhanced seismic data expresses seismic data as a convolution of reflectivity and a seismic source wavelet. This seismic source wavelet varies over a sampling interval and defining a total amount of energy over the sampling interval. An enhanced seismic source wavelet that is a single-valued energy spike that yields the total amount of energy over the sampling interval is generated. In addition, the reflectivity is modified to preserve amplitude variation with angle. The reflectivity is convoluted with the enhanced seismic source wavelet and residual energy is added to the convolution to generate the spectrally enhanced seismic data.

Embodiments of the invention provide a method for classifying seismic attributes, including generating data points by cross plotting seismic attributes from a first data volume and a second data volume, encompassing at least one of the generated data points within a polygon, generating a reference line, determining an interpolation direction relative to the reference line, and assigning an attribute value to the at least one generated data point encompassed within the polygon wherein the assigned attribute value is interpolated based on the combination of its position to the reference line along the interpolation direction and the shape of the polygon.

A method is described for a manner of geologic analysis using seismic data. The method includes steps to produce improved amplitude versus angle (AVA) information that may be used for analysis of geologic features of interest including estimation of pore fluid content. The method assesses the probability of hydrocarbons in a subterranean reservoir based on seismic amplitude variations along offsets or angles for portions of a seismic horizon. The method may be executed by a computer system.

Method and apparatus for separating seismic diffracted waves, in seismic exploration field. The method comprises acquiring seismic shot gather data carrying underground geological information in preset geological region; inputting preprocessed single-shot data obtained by preprocessing seismic shot gather data and a preset migration velocity model to three-dimensional single-shot angle domain imaging formula and performing wave field back-propagation processing on the seismic shot gather data to obtain information of azimuth, emergence angle and amplitude of propagation rays, according to which three-dimensional angle domain imaging matrix is generated, the obtained information corresponding one by one to underground imaging points in the preset geological region; separating low-rank matrix component from the three-dimensional angle domain imaging matrix and determining the low-rank matrix component as the seismic diffracted wave through a preset three-dimensional diffracted wave separating model, improving amplitude integrity and waveform consistency of separated diffracted waves and imaging resolution of geological structures.

A method including: obtaining intercept and gradient stacks and an effective stress volume that correspond to seismic data for a subsurface region; determining Chi angles as a function of effective stress; and generating a seismic volume with the Chi angles that vary as a function of effective stress.

A method for inversion of 4D seismic data, the method including: determining time shift between baseline and monitor geophysical datasets; determining time strain from the time shift; iteratively repeating until a stopping criteria is satisfied, performing an iterative elastic AVO inversion with a 4D difference providing an update, from an initial model including the time strain, to generate an updated time strain and an updated physical property model, wherein the stopping criteria is a misfit between synthetic data generated from the updated physical property model and the 4D difference being within a predetermined noise level, wherein for each successive iteration, the method includes generating an updated time shift from the updated time strain, generating an updated 4D difference from the updated time strain, generating a new time strain from the updated 4D difference, and repeating the AVO inversion with the updated 4D difference and the new time strain; generating final values for the physical property model; and converting, with a rock physics model or a reservoir simulation model, the final values to saturation and/or pressure changes for a subsurface region.

A method of geophysical exploration in a seismic survey includes acquiring a set of seismic traces based on seismic data obtained by a seismic receiver, responsive to seismic energy reflected from a subsurface geology. Additional steps include performing reverse time migration on the seismic traces using a velocity model that represents velocity of the seismic energy propagating through the seismic medium. The migrated gathers have an amplitude based at least in part on the migration, which can be corrected by computing synthetic seismograms to provide compensated gathers. Amplitude versus offset and/or amplitude versus angle analysis can be performed on the compensated gathers, in order to generate a seismic image of subsurface structures in the survey area.

A method can include receiving values of an inversion based at least in part on seismic amplitude variation with azimuth (AVAz) data for a region of a geologic environment; based at least in part on the received values, computing values that depend on components of a second-rank tensor ij, selecting a fracture height for fractures in the geologic environment; selecting an azimuth for a first fracture set of the fractures; based at least in part on the values for the second-rank tensor ij; the fracture height and the selected azimuth, determining an azimuth for a second fracture set of the fractures; and generating a discrete fracture network (DFN) for at least a portion of the region of the geologic environment where the discrete fracture network (DFN) includes fractures of the first fracture set and fractures of the second fracture set.

A method for angle-domain common image gather (ADCIG) of a subsurface formation includes the step of converting seismic incident waves and seismic scattered waves at each of a number of image locations from time domain to frequency domain using Fourier transform. At each image location, the seismic waves in the frequency domain are decomposed into a number of local plane waves. Applying a cross-correlating imaging condition amongst the local plane waves to obtain a partial image at each image location. The plurality of partial images are then sorted into the angle domain.

A computer-implemented method for determining rock and fluid parameters of a subsurface region from measured seismic reflection data, said method including: generating, with a computer, a geophysical data volume by combining a plurality of angle stacks obtained from the measured seismic reflection data and geophysical property data obtained from a full wavefield inversion of the measured seismic reflection data; for each point of the geophysical data volume, determining, with a computer, a petrophysical model that is a probability of a rock state based on initial values of the rock and fluid parameters and the geophysical data volume; iteratively determining, using a computer, updated values for the rock and fluid parameters, wherein the iteratively determining includes determining a petrophysical parameter estimate for the rock and fluid parameters from the petrophysical model as constrained by the geophysical data volume and the initial values of the rock and fluid parameters, minimizing a misfit between the geophysical data volume and synthetic data generated from a forward modeling of the initial values of the rock and fluid parameters using a cost function that includes the petrophysical parameter estimate of the rock and fluid parameters, and repeating the iteratively determining until a predetermined stopping criteria is satisfied and final values for the rock and fluid parameters are generated, and each subsequent iteration of the iteratively determining replaces the initial values for the rock and fluid parameters with the updated values for the rock and fluid parameters from a previous iteration; determining, with a computer, uncertainty in the final values for the rock and fluid parameters; and exploring for or producing hydrocarbons using the final values for the rock and fluid parameters and there uncertainty.